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%% Papers Published
@article{fds365216,
Author = {Wiley, L and Follansbee, J and Leslie, P and Furxhi, O and Pimpinella,
R and Brady, D and Driggers, R},
Title = {Target discrimination in the extended SWIR (eSWIR) band
(2-2.5μm) compared to Vis, NIR, and SWIR in degraded visual
environments},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {12106},
Year = {2022},
Month = {January},
ISBN = {9781510650886},
url = {http://dx.doi.org/10.1117/12.2618566},
Abstract = {Long-range target identification is well studied in the
Visible (Vis) and near-infrared (NIR) bands, and more
recently in the shortwave infrared (SWIR). The longer
wavelength of SWIR (1-1.7μm) improves target detection for
both long ranges and under challenging atmospheric
conditions because it is less limited by scattering and
absorption in the atmosphere. For these reasons, SWIR
sensors are proliferating on military platforms. The
extended shortwave infrared (eSWIR) band spanning from 2 to
2.5μm is not typically limited by diffraction, and, as a
result, the band benefits target acquisition both at long
ranges and for degraded visual environments. Theoretical and
experimental data compare eSWIR to Vis, NIR, and SWIR for
atmospheric transmission, reflectivity, illumination, and
sensor resolution and sensitivity. The experimental setup
includes two testbeds, each with four cameras. The first is
a wide field of view (FOV) testbed matching FOV at 20
degrees for each camera. The second is a narrow FOV
telescope testbed to match instantaneous FOV (IFOV) for
consistent resolution across all four bands at long ranges.
Both the theory and experiment demonstrate advantages of
using eSWIR for long-range target identification under
degraded visual environments.},
Doi = {10.1117/12.2618566},
Key = {fds365216}
}
@article{fds366169,
Author = {Revello, C and Driggers, R and Brady, D and Renshaw,
K},
Title = {Large area coverage using drone mounted multi-camera
systems},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {12106},
Year = {2022},
Month = {January},
ISBN = {9781510650886},
url = {http://dx.doi.org/10.1117/12.2618708},
Abstract = {The recent advancements in commercial drone performance and
capability have seen their use in private industries
proliferate. In terms of large area coverage, low-flying
drones can accomplish the same tasks as larger unmanned
aerial vehicles (UAVs) and small manned aircraft.
Traditional methods of capturing this imagery, including
single wide field of view (WFOV) cameras and gimbal-mounted
systems, can be replaced by small camera arrays. Single WFOV
lenses deliver poor resolution at the ground level.
Similarly, the use of a narrow field of view (NFOV) lens
would necessitate the use of a gimbal, a pivoted support
used in camera stabilization-yielding a heavier, more
expensive system that relies on additional moving parts. By
utilizing multiple lightweight sensors, large area coverage
while maintaining good ground sample resolution can be
achieved as well as promise a more robust system. This paper
will explore the creation and testing of one such system,
describe a means by which more advanced systems can be
developed, and introduce a metric so as to compare its
performance against various modeled systems.},
Doi = {10.1117/12.2618708},
Key = {fds366169}
}
@article{fds367700,
Author = {Hu, M and Brady, DJ},
Title = {Array Camera Sampling Optimization},
Journal = {Optics Infobase Conference Papers},
Year = {2022},
Month = {January},
ISBN = {9781557528209},
Abstract = {We consider sampling system optimization in the context of
deep-learning-based data fusion for dynamic high depth of
field events, such as baseball. We show that multiscale
spatio-spectral-focal-temporal sampling is
ideal.},
Key = {fds367700}
}
@article{fds360669,
Author = {Brady, DJ},
Title = {Optical Processing for Artificial Neural
Vision},
Journal = {2021 Conference on Lasers and Electro Optics, Cleo 2021
Proceedings},
Year = {2021},
Month = {May},
ISBN = {9781943580910},
Abstract = {Convolutional neural networks have become established as the
primary mechanisms for image processing over the past
decade. While general purpose optical neural networks remain
a long term project, in the near term optical prefilters act
as the first layers of electronic deep convolutional
networks and enable 10-100x reduction in system power per
reconstructed voxel.},
Key = {fds360669}
}
@article{fds360094,
Author = {Brady, DJ},
Title = {Optical processing for artificial neural
vision},
Journal = {Optics Infobase Conference Papers},
Year = {2021},
Month = {January},
ISBN = {9781557528209},
Abstract = {Convolutional neural networks have become established as the
primary mechanisms for image processing over the past
decade. While general purpose optical neural networks remain
a long term project, in the near term optical prefilters act
as the first layers of electronic deep convolutional
networks and enable 10-100x reduction in system power per
reconstructed voxel.},
Key = {fds360094}
}
@article{fds362466,
Author = {Yamaguchi, K and Brady, DJ},
Title = {Image quality improvement in Fresnel zone aperture-based
lensless camera with ptychography-inspired
reconstruction},
Journal = {Optics Infobase Conference Papers},
Year = {2021},
Month = {January},
ISBN = {9781557528209},
Abstract = {To overcome the resolution and noise limits in Fresnel zone
aperture-based lensless cameras, two types of multi-shot
imaging are proposed. Simulated results show these methods
successfully suppress the effect of sensor noise and
diffraction.},
Key = {fds362466}
}
@article{fds353033,
Author = {Wang, X and Zhang, X and Zhu, Y and Guo, Y and Yuan, X and Xiang, L and Wang,
Z and Ding, G and Brady, D and Dai, Q and Fang, L},
Title = {Panda: A gigapixel-level human-centric video
dataset},
Journal = {Proceedings of the Ieee Computer Society Conference on
Computer Vision and Pattern Recognition},
Pages = {3265-3275},
Year = {2020},
Month = {January},
url = {http://dx.doi.org/10.1109/CVPR42600.2020.00333},
Abstract = {We present PANDA, the first gigaPixel-level humAN-centric
viDeo dAtaset, for large-scale, long-term, and multi-object
visual analysis. The videos in PANDA were captured by a
gigapixel camera and cover real-world scenes with both wide
field-of-view (∼1 km2 area) and high-resolution details
(∼gigapixel-level/frame). The scenes may contain 4k head
counts with over 100× scale variation. PANDA provides
enriched and hierarchical ground-truth annotations,
including 15, 974.6k bounding boxes, 111.8k fine-grained
attribute labels, 12.7k trajectories, 2.2k groups and 2.9k
interactions. We benchmark the human detection and tracking
tasks. Due to the vast variance of pedestrian pose, scale,
occlusion and trajectory, existing approaches are challenged
by both accuracy and efficiency. Given the uniqueness of
PANDA with both wide FoV and high resolution, a new task of
interaction-aware group detection is introduced. We design a
‘global-to-local zoom-in’ framework, where global
trajectories and local interactions are simultaneously
encoded, yielding promising results. We believe PANDA will
contribute to the community of artificial intelligence and
praxeology by understanding human behaviors and interactions
in large-scale real-world scenes. PANDA Website:
http://www.panda-dataset.com.},
Doi = {10.1109/CVPR42600.2020.00333},
Key = {fds353033}
}
@article{fds357859,
Author = {Zhang, W and Cao, L and Zhang, H and Jin, G and Brady,
DJ},
Title = {Signal decoupling in digital holography via compressive
sensing},
Journal = {Ieee International Symposium on Industrial
Electronics},
Volume = {2019-June},
Pages = {2414-2418},
Year = {2019},
Month = {June},
ISBN = {9781728136660},
url = {http://dx.doi.org/10.1109/ISIE.2019.8781303},
Abstract = {Digital holography (DH) could realize three dimensional
(3-D) imaging since it records the wavefront induced by an
object volume. However, DH suffers from two inherent
drawbacks for 3-D imaging: the twin images and cross talks
between different depths. Both these two terms severely
trouble DH because they couple with the reconstructed
signal, particularly under microscopic configuration. In
this work, we briefly review the signal decoupling
techniques in DH and introduce the achieved micron-level
depth-resolved uncoupled signal reconstruction via
compressive sensing (CS). As an optimization strategy for
signal reconstruction, CS is capable of filtering out the
coupled signals by sparsity constraint. The CS based signal
decoupling in DH is analyzed and verified by numerical
simulations and optical experiments.},
Doi = {10.1109/ISIE.2019.8781303},
Key = {fds357859}
}
@article{fds349960,
Author = {Zhang, W and Zhang, H and Brady, DJ and Jin, G and Cao,
L},
Title = {Compressive depth-resolved holographic microscope},
Journal = {Proceedings Digital Holography and Three Dimensional Imaging
2019},
Year = {2019},
Month = {May},
ISBN = {9781943580590},
url = {http://dx.doi.org/10.1364/DH.2019.Th3A.8},
Abstract = {Holographic imaging suffers from twin images and cross-talks
between different layers of three-dimensional objects even
at millimeter scale. Compressive sensing associated with
holographic microscope achieves micron level depth-resolved
imaging free from the mentioned noises above.},
Doi = {10.1364/DH.2019.Th3A.8},
Key = {fds349960}
}
@article{fds350188,
Author = {Zhang, W and Zhang, H and Brady, DJ and Jin, G and Cao,
L},
Title = {Compressive depth-resolved holographic microscope},
Journal = {Optics Infobase Conference Papers},
Year = {2019},
Month = {May},
ISBN = {9781943580590},
Abstract = {Holographic imaging suffers from twin images and cross-talks
between different layers of three-dimensional objects even
at millimeter scale. Compressive sensing associated with
holographic microscope achieves micron level depth-resolved
imaging free from the mentioned noises above.},
Key = {fds350188}
}
@article{fds337116,
Author = {Linnehan, R and Schindler, J and Perlovsky, L and Rangaswamy, M and Brady, D},
Title = {Phenomenology-based waveform design using Cramer-Rao
theory},
Journal = {2004 International Waveform Diversity and Design Conference,
Wdd 2004 Proceedings},
Volume = {2018-January},
Pages = {1-5},
Publisher = {IEEE},
Year = {2018},
Month = {March},
ISBN = {9781509031771},
url = {http://dx.doi.org/10.1109/IWDDC.2004.8317555},
Abstract = {The Cramer Rao Bound (CRB) establishes a lower bound on the
error variance of an unbiased parameter estimate [5]. We
have derived CRBs for target parameter estimates using
synthetic aperture radar (SAR), and allow for spatial
waveform diversity. The first application is to target
reflectivity with the assumption that all scatterer
positions are known. Using a standard scattering model we
are able to verify theoretical results with numerical
experiments. The development is then applied to target
height, assuming the height and ground range are jointly
estimated for all scatterers simultaneously. Here we show
that height can in fact be estimated with vertical excursion
in the aperture.},
Doi = {10.1109/IWDDC.2004.8317555},
Key = {fds337116}
}
@article{fds336966,
Author = {Zhang, W and Cao, L and Zhang, H and Jin, G and Brady,
D},
Title = {Noise reduction in digital holography based on a filtering
algorithm},
Journal = {Progress in Biomedical Optics and Imaging Proceedings of
Spie},
Volume = {10503},
Publisher = {SPIE},
Year = {2018},
Month = {January},
ISBN = {9781510614918},
url = {http://dx.doi.org/10.1117/12.2288729},
Abstract = {Holography is a tool to record the object wavefront by
interference. Complex amplitude of the object wave is coded
into a two dimensional hologram. Unfortunately, the
conjugate wave and background wave would also appear at the
object plane during reconstruction, as noise, which blurs
the reconstructed object. From the perspective of wave, we
propose a filtering algorithm to get a noise-reduced
reconstruction. Due to the fact that the hologram is a kind
of amplitude grating, three waves would appear when
reconstruction, which are object wave, conjugate wave and
background wave. The background is easy to eliminate by
frequency domain filtering. The object wave and conjugate
wave are signals to be dealt with. These two waves, as a
whole, propagate in the space. However, when detected at the
original object plane, the object wave would diffract into a
sparse pattern while the conjugate wave would diffract into
a diffused pattern forming the noise. Hence, the noise can
be reduced based on these difference with a filtering
algorithm. Both amplitude and phase distributions are
truthfully retrieved in our simulation and experimental
demonstration.},
Doi = {10.1117/12.2288729},
Key = {fds336966}
}
@article{fds340529,
Author = {Pang, W and Brady, DJ},
Title = {Configurable cameras with MMS architecture},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {10845},
Publisher = {SPIE},
Year = {2018},
Month = {January},
ISBN = {9781510623323},
url = {http://dx.doi.org/10.1117/12.2504750},
Abstract = {Monocentric multiscale (MMS) lens architecture provides a
versatile, compact, high information efficiency and low-cost
way of building panoramic imagers which can be easily
tailored to various application scenarios. MMS lens consists
of two parts, one concentric spherical objective lens with
large aperture in front and an array of small aperture
microcameras in rear. This front objective collects incoming
light and forms a curved focal surface which is then being
segmented and relayed by the secondary array optics. Since
the front objective is a spherically symmetric element, the
configuration of the secondary array optics determines the
overall imaging space. Each microcamera can be used as a
building block and offers the flexibility of compositing
myriad of FoV coverage and easy re-configuration. Another
merit of this modular design is that the design of the
secondary optics can be varied from channel to channel. In
this way, we can construct an imaging system with
multi-focal lengths, multi-aperture sizes and other
multi-specifications. This varied channel property allows
for sub-region adaptive imaging ability. Finally, if
multiple MMS lenses are co-designed and used jointly, some
combinational functions can be accomplished. To verify these
virtues of MMS architecture, we present several design
examples in this paper. A rectangular and a 360-degree ring
configuration are demonstrated and show different packing
choices. Then we illustrate a multi-focal design which shows
secondary optics of different channels are modified for a
relatively uniform sampling rate of targeted
area.},
Doi = {10.1117/12.2504750},
Key = {fds340529}
}
@article{fds331444,
Author = {Yuan, X and Fang, L and Dai, Q and Brady, DJ and Liu,
Y},
Title = {Multiscale gigapixel video: A cross resolution image
matching and warping approach},
Journal = {2017 Ieee International Conference on Computational
Photography, Iccp 2017 Proceedings},
Publisher = {IEEE},
Year = {2017},
Month = {June},
ISBN = {9781509057450},
url = {http://dx.doi.org/10.1109/ICCPHOT.2017.7951481},
Abstract = {We present a multi-scale camera array to capture and
synthesize gigapixel videos in an efficient way. Our
acquisition setup contains a reference camera with a
short-focus lens to get a large field-of-view video and a
number of unstructured long-focus cameras to capture
local-view details. Based on this new design, we propose an
iterative feature matching and image warping method to
independently warp each local-view video to the reference
video. The key feature of the proposed algorithm is its
robustness to and high accuracy for the huge resolution gap
(more than 8x resolution gap between the reference and the
local-view videos), camera parallaxes, complex scene
appearances and color inconsistency among cameras.
Experimental results show that the proposed multi-scale
camera array and cross resolution video warping scheme is
capable of generating seamless gigapixel video without the
need of camera calibration and large overlapping area
constraints between the local-view cameras.},
Doi = {10.1109/ICCPHOT.2017.7951481},
Key = {fds331444}
}
@article{fds330737,
Author = {Pang, W and Brady, DJ},
Title = {Parallel MMS gigapixel imagers},
Journal = {Optics Infobase Conference Papers},
Volume = {Part F46-COSI 2017},
Publisher = {OSA},
Year = {2017},
Month = {January},
ISBN = {9781943580293},
url = {http://dx.doi.org/10.1364/COSI.2017.CM2B.3},
Abstract = {We present a new architecture for monocentric multiscale
(MMS) gigapixel imagers. This new architecture parallels
multiple MMS imagers together to interleave a continuous
wide field-of-view (FOV) coverage, resulting in a more
compact system layout.},
Doi = {10.1364/COSI.2017.CM2B.3},
Key = {fds330737}
}
@article{fds330738,
Author = {Zhang, W and Cao, L and Cang, J and Jin, G and Brady,
D},
Title = {Resolution enhancement with a grating in lens-less digital
holographic imaging},
Journal = {Optics Infobase Conference Papers},
Volume = {Part F47-DH 2017},
Publisher = {OSA},
Year = {2017},
Month = {January},
ISBN = {9781557528209},
url = {http://dx.doi.org/10.1364/DH.2017.M2A.4},
Abstract = {The imaging resolution is enhanced with multiple diffraction
orders from a grating in front of the sensor in lens-less
digital holography. A 1024 × 1024 image is reconstructed
from a 640 × 480 hologram with the proposed
algorithm.},
Doi = {10.1364/DH.2017.M2A.4},
Key = {fds330738}
}
@article{fds330739,
Author = {Brady, D},
Title = {Recent advances in gigapixel cameras},
Journal = {Optics Infobase Conference Papers},
Volume = {Part F46-COSI 2017},
Publisher = {OSA},
Year = {2017},
Month = {January},
ISBN = {9781943580293},
url = {http://dx.doi.org/10.1364/COSI.2017.CTu4B.2},
Abstract = {Continuing advances in computational architecture, optical
design and software have reduced gigapixel camera system
volume by more than two orders of magnitude and have also
greatly advanced system utility.},
Doi = {10.1364/COSI.2017.CTu4B.2},
Key = {fds330739}
}
@article{fds322143,
Author = {Odinaka, I and Kaganovsky, Y and Greenberg, JA and Hassan, M and Politte, DG and O'Sullivan, JA and Carin, L and Brady,
DJ},
Title = {Spectrally grouped total variation reconstruction for
scatter imaging using ADMM},
Journal = {2015 Ieee Nuclear Science Symposium and Medical Imaging
Conference, Nss/Mic 2015},
Publisher = {IEEE},
Year = {2016},
Month = {October},
ISBN = {9781467398626},
url = {http://dx.doi.org/10.1109/NSSMIC.2015.7582220},
Abstract = {We consider X-ray coherent scatter imaging, where the goal
is to reconstruct momentum transfer profiles (spectral
distributions) at each spatial location from multiplexed
measurements of scatter. Each material is characterized by a
unique momentum transfer profile (MTP) which can be used to
discriminate between different materials. We propose an
iterative image reconstruction algorithm based on a Poisson
noise model that can account for photon-limited measurements
as well as various second order statistics of the data. To
improve image quality, previous approaches use
edge-preserving regularizers to promote piecewise constancy
of the image in the spatial domain while treating each
spectral bin separately. Instead, we propose spectrally
grouped regularization that promotes piecewise constant
images along the spatial directions but also ensures that
the MTPs of neighboring spatial bins are similar, if they
contain the same material. We demonstrate that this group
regularization results in improvement of both spectral and
spatial image quality. We pursue an optimization transfer
approach where convex decompositions are used to lift the
problem such that all hyper-voxels can be updated in
parallel and in closed-form. The group penalty introduces a
challenge since it is not directly amendable to these
decompositions. We use the alternating directions method of
multipliers (ADMM) to replace the original problem with an
equivalent sequence of sub-problems that are amendable to
convex decompositions, leading to a highly parallel
algorithm. We demonstrate the performance on real
data.},
Doi = {10.1109/NSSMIC.2015.7582220},
Key = {fds322143}
}
@article{fds325880,
Author = {McCain, S and Feller, S and Brady, D},
Title = {Gigapixel television},
Journal = {Optics Infobase Conference Papers},
Volume = {Part F7-COSI 2016},
Publisher = {OSA},
Year = {2016},
Month = {July},
ISBN = {9781943580156},
url = {http://dx.doi.org/10.1364/COSI.2016.CTh3B.5},
Abstract = {We consider image capture and real-time rendering for
virtual reality television. Array cameras enable multiuser
digital pan, tilt, zoom and view point translation but
require novel optical and electronic architectures. © OSA
2016.},
Doi = {10.1364/COSI.2016.CTh3B.5},
Key = {fds325880}
}
@article{fds325879,
Author = {Llull, P and Reeves, G and Carin, L and Brady, DJ},
Title = {Performance assessment of image translation-engineered point
spread functions},
Journal = {Optics Infobase Conference Papers},
Volume = {Part F7-COSI 2016},
Publisher = {OSA},
Year = {2016},
Month = {July},
ISBN = {9781943580156},
url = {http://dx.doi.org/10.1364/COSI.2016.CW2D.4},
Abstract = {We demonstrate image translation, a general method for
task-dependent point spread function engineering. Here, we
compare the optical performance of variations of image
translation with several well known imaging methods. © OSA
2016.},
Doi = {10.1364/COSI.2016.CW2D.4},
Key = {fds325879}
}
@article{fds323370,
Author = {Greenberg, J and Iniewski, K and Brady, D},
Title = {CZT detector modeling for coded aperture X-ray diffraction
imaging applications},
Journal = {2014 Ieee Nuclear Science Symposium and Medical Imaging
Conference, Nss/Mic 2014},
Publisher = {IEEE},
Year = {2016},
Month = {March},
ISBN = {9781479960972},
url = {http://dx.doi.org/10.1109/NSSMIC.2014.7431271},
Abstract = {CZT detectors are primary candidates for many
next-generation X-ray diffraction imaging systems. We have
conducted a study to evaluate performance tradeoffs and
limitations of CZT energy-sensitive detectors in coded
aperture X-ray imaging (CAXI) architectures. We have found,
as expected, that performance of the coded aperture
architecture depends critically on energy resolution (ER) of
the detector. We have also found that spectrum tail, as
measured for mono-energetic sources, is less important
although the incomplete charge collection leads to distorted
system level information. We have built a mathematical model
for the energy spectrum that can be used to optimize the
detector geometry (pixel size, detector thickness), detector
fabrication (injecting vs. non-injecting contacts) and
operating conditions (HV bias, count rate) for the optimum
performance of the coded aperture X-ray imaging
systems.},
Doi = {10.1109/NSSMIC.2014.7431271},
Key = {fds323370}
}
@article{fds323371,
Author = {Holmgren, AD and Odinaka, I and Greenberg, JA and Brady,
DJ},
Title = {Multi-view coded aperture coherent scatter
tomography},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {9847},
Publisher = {SPIE},
Year = {2016},
Month = {January},
ISBN = {9781510600881},
url = {http://dx.doi.org/10.1117/12.2223871},
Abstract = {We use coded apertures and multiple views to create a
compressive coherent scatter computed tomography (CSCT)
system. Compared with other CSCT systems, we reduce object
dose and scan time. Previous work on coded aperture
tomography resulted in a resolution anisotropy that caused
poor or unusable momentum transfer resolution in certain
cases. Complimentary and multiple views resolve the
resolution issues, while still providing the ability to
perform snapshot tomography by adding sources and
detectors.},
Doi = {10.1117/12.2223871},
Key = {fds323371}
}
@article{fds323372,
Author = {Greenberg, JA and Brady, DJ},
Title = {Snapshot full-volume coded aperture x-ray diffraction
tomography},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {9847},
Publisher = {SPIE},
Year = {2016},
Month = {January},
ISBN = {9781510600881},
url = {http://dx.doi.org/10.1117/12.2223838},
Abstract = {X-ray diffraction tomography (XRDT) is a well-established
technique that makes it possible to identify the material
composition of an object throughout its volume. We show that
using coded apertures to structure the measured scatter
signal gives rise to a family of imaging architectures than
enables snapshot XRDT in up to 4-dimensions. We consider
pencil, fan, and cone beam snapshot XRDT and show results
from both experimental and simulation-based studies. We find
that, while lower-dimensional systems typically result in
higher imaging fidelity, higher-dimensional systems can
perform adequately for a specific task at orders of
magnitude faster scan times.},
Doi = {10.1117/12.2223838},
Key = {fds323372}
}
@article{fds323373,
Author = {Greenberg, JA and Hassan, M and Brady, DJ and Iniewski,
K},
Title = {High precision, medium flux rate CZT spectroscopy for
coherent scatter imaging},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {9847},
Publisher = {SPIE},
Year = {2016},
Month = {January},
ISBN = {9781510600881},
url = {http://dx.doi.org/10.1117/12.2221913},
Abstract = {CZT detectors are primary candidates for many
next-generation X-ray imaging systems. These detectors are
typically operated in either a high precision, low flux
spectroscopy mode or a low precision, high flux photon
counting mode. We demonstrate a new detector configuration
that enables operation in a high precision, medium flux
spectroscopy mode, which opens the potential for a variety
of new applications in medical imaging, non-destructive
testing and baggage scanning. In particular, we describe the
requirements of a coded aperture coherent scattering X-ray
system that can perform fast imaging with accurate material
discrimination.},
Doi = {10.1117/12.2221913},
Key = {fds323373}
}
@article{fds323374,
Author = {Hassan, M and Holmgren, A and Greenberg, JA and Odinaka, I and Brady,
D},
Title = {Impact of detector geometry for compressive fan beam
snapshot coherent scatter imaging},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {9847},
Publisher = {SPIE},
Year = {2016},
Month = {January},
ISBN = {9781510600881},
url = {http://dx.doi.org/10.1117/12.2224797},
Abstract = {Previous realizations of coded-aperture X-ray diffraction
tomography (XRDT) techniques based on pencil beams image one
line through an object via a single measurement but require
raster scanning the object in multiple dimensions. Fan beam
approaches are able to image the spatial extent of the
object while retaining the ability to do material
identification. Building on these approaches we present our
system concept and geometry of combining a fan beam with
energy sensitive/photon counting detectors and a coded
aperture to capture both spatial and spectral information
about an object at each voxel. Using our system we image
slices via snapshot measurements for four different detector
configurations and compare their results.},
Doi = {10.1117/12.2224797},
Key = {fds323374}
}
@article{fds322146,
Author = {Odinaka, I and Greenberg, JA and Kaganovsky, Y and Holmgren, A and Hassan, M and Politte, DG and O'Sullivan, JA and Carin, L and Brady,
DJ},
Title = {Coded aperture x-ray diffraction imaging with transmission
computed tomography side-information},
Journal = {Progress in Biomedical Optics and Imaging Proceedings of
Spie},
Volume = {9783},
Publisher = {SPIE},
Year = {2016},
Month = {January},
ISBN = {9781510600188},
url = {http://dx.doi.org/10.1117/12.2216915},
Abstract = {Coded aperture X-ray diffraction (coherent scatter spectral)
imaging provides fast and dose-efficient measurements of the
molecular structure of an object. The information provided
is spatially-dependent and material-specific, and can be
utilized in medical applications requiring material
discrimination, such as tumor imaging. However, current
coded aperture coherent scatter spectral imaging system
assume a uniformly or weakly attenuating object, and are
plagued by image degradation due to non-uniform
self-attenuation. We propose accounting for such
non-uniformities in the self-attenuation by utilizing an
X-ray computed tomography (CT) image (reconstructed
attenuation map). In particular, we present an iterative
algorithm for coherent scatter spectral image
reconstruction, which incorporates the attenuation map, at
different stages, resulting in more accurate coherent
scatter spectral images in comparison to their uncorrected
counterpart. The algorithm is based on a spectrally grouped
edge-preserving regularizer, where the neighborhood edge
weights are determined by spatial distances and attenuation
values.},
Doi = {10.1117/12.2216915},
Key = {fds322146}
}
@article{fds322147,
Author = {Odinaka, I and Kaganovsky, Y and O'Sullivan, JA and Politte, DG and Holmgren, AD and Greenberg, JA and Carin, L and Brady,
DJ},
Title = {Domain and range decomposition methods for coded aperture
x-ray coherent scatter imaging},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {9847},
Publisher = {SPIE},
Year = {2016},
Month = {January},
ISBN = {9781510600881},
url = {http://dx.doi.org/10.1117/12.2224265},
Abstract = {Coded aperture X-ray coherent scatter imaging is a novel
modality for ascertaining the molecular structure of an
object. Measurements from different spatial locations and
spectral channels in the object are multiplexed through a
radiopaque material (coded aperture) onto the detectors.
Iterative algorithms such as penalized expectation
maximization (EM) and fully separable spectrally-grouped
edge-preserving reconstruction have been proposed to recover
the spatially-dependent coherent scatter spectral image from
the multiplexed measurements. Such image recovery methods
fall into the category of domain decomposition methods since
they recover independent pieces of the image at a time.
Ordered subsets has also been utilized in conjunction with
penalized EM to accelerate its convergence. Ordered subsets
is a range decomposition method because it uses parts of the
measurements at a time to recover the image. In this paper,
we analyze domain and range decomposition methods as they
apply to coded aperture X-ray coherent scatter imaging using
a spectrally-grouped edge-preserving regularizer and discuss
the implications of the increased availability of parallel
computational architecture on the choice of decomposition
methods. We present results of applying the decomposition
methods on experimental coded aperture X-ray coherent
scatter measurements. Based on the results, an underlying
observation is that updating different parts of the image or
using different parts of the measurements in parallel,
decreases the rate of convergence, whereas using the parts
sequentially can accelerate the rate of convergence.},
Doi = {10.1117/12.2224265},
Key = {fds322147}
}
@article{fds280131,
Author = {Greenberg, JA and Lakshamanan, MN and Brady, DJ and Kapadia,
A},
Title = {Optimization of a coded aperture coherent scatter spectral
imaging system for medical imaging},
Journal = {Proc. Spie 9412, Medical Imaging 2015: Physics of Medical
Imaging,},
Volume = {94125E},
Publisher = {SPIE},
Year = {2015},
Month = {January},
ISBN = {9781628415025},
ISSN = {1605-7422},
url = {http://dx.doi.org/10.1117/12.2082110},
Abstract = {Coherent scatter X-ray imaging is a technique that provides
spatially-resolved information about the molecular structure
of the material under investigation, yielding
material-specific contrast that can aid medical diagnosis
and inform treatment. In this study, we demonstrate a
coherent-scatter imaging approach based on the use of coded
apertures (known as coded aperture coherent scatter spectral
imaging1, 2) that enables fast, dose-efficient,
high-resolution scatter imaging of biologically-relevant
materials. Specifically, we discuss how to optimize a coded
aperture coherent scatter imaging system for a particular
set of objects and materials, describe and characterize our
experimental system, and use the system to demonstrate
automated material detection in biological
tissue.},
Doi = {10.1117/12.2082110},
Key = {fds280131}
}
@article{fds291361,
Author = {Kaganovsky, Y and Degirmenci, S and Han, S and Odinaka, I and Politte,
DG and Brady, DJ and O'Sullivan, JA and Carin, L},
Title = {Alternating minimization algorithm with iteratively
reweighted quadratic penalties for compressive transmission
tomography},
Journal = {Progress in Biomedical Optics and Imaging Proceedings of
Spie},
Volume = {9413},
Publisher = {SPIE},
Year = {2015},
Month = {January},
ISBN = {9781628415032},
ISSN = {1605-7422},
url = {http://dx.doi.org/10.1117/12.2081986},
Abstract = {We propose an alternating minimization (AM) algorithm for
estimating attenuation functions in X-ray transmission
tomography using priors that promote sparsity in the
pixel/voxel differences domain. As opposed to standard
maximum-a-posteriori (MAP) estimation, we use the automatic
relevance determination (ARD) framework. In the ARD
approach, sparsity (or compressibility) is promoted by
introducing latent variables which serve as the weights of
quadratic penalties, with one weight for each pixel/voxel;
these weights are then automatically learned from the data.
This leads to an algorithm where the quadratic penalty is
reweighted in order to effectively promote sparsity. In
addition to the usual object estimate, ARD also provides
measures of uncertainty (posterior variances) which are used
at each iteration to automatically determine the trade-off
between data fidelity and the prior, thus potentially
circumventing the need for any tuning parameters. We apply
the convex decomposition lemma in a novel way and derive a
separable surrogate function that leads to a parallel
algorithm. We propose an extension of branchless
distance-driven forward/back-projections which allows us to
considerably speed up the computations associated with the
posterior variances. We also study the acceleration of the
algorithm using ordered subsets.},
Doi = {10.1117/12.2081986},
Key = {fds291361}
}
@article{fds323552,
Author = {Llull, P and Yuan, X and Liao, X and Yang, J and Kittle, D and Carin, L and Sapiro, G and Brady, DJ},
Title = {Temporal compressive sensing for video},
Number = {9783319160412},
Pages = {41-74},
Publisher = {Springer International Publishing},
Year = {2015},
Month = {January},
ISBN = {9783319160412},
url = {http://dx.doi.org/10.1007/978-3-319-16042-9_2},
Abstract = {Video camera architects must design cameras capable of
high-quality, dynamic event capture, while adhering to power
and communications constraints. Though modern imagers are
capable of both simultaneous spatial and temporal
resolutions at micrometer and microsecond scales, the power
required to sample at these rates is undesirable. The field
of compressive sensing (CS) has recently suggested a
solution to this design challenge. By exploiting
physical-layer compression strategies, one may overlay the
original scene with a coding sequence to sample at
sub-Nyquist rates with virtually no additional power
requirement. The underlying scene may be later estimated
without significant loss of fidelity. In this chapter, we
cover a variety of such strategies taken to improve an
imager’s temporal resolution. Highlighting a new low-power
acquisition paradigm, we show how a video sequence of high
temporal resolution may be reconstructed from a single video
frame taken with a low-framerate camera.},
Doi = {10.1007/978-3-319-16042-9_2},
Key = {fds323552}
}
@article{fds365929,
Author = {Chen, EX and Lian, W and Carin, L and Brady, DJ},
Title = {Task-driven Adaptive Sensing on Quadrupole Mass Filter
Systems for Classification},
Journal = {Optics Infobase Conference Papers},
Year = {2015},
Month = {January},
ISBN = {9781557528209},
Abstract = {An information-theoretical adaptive sensing and
classification framework is proposed for Quadrupole mass
filter systems. Simulation results demonstrate significant
reduction in number of measurement and improvement of
classification accuracy using the adaptive approach compared
with baselines.},
Key = {fds365929}
}
@article{fds365930,
Author = {Tsai, TH and Llull, P and Yuan, X and Carin, L and Brady,
DJ},
Title = {Coded Aperture Compressive Spectral-Temporal
Imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2015},
Month = {January},
ISBN = {9781557528209},
Abstract = {We present a compressive camera that combines mechanical
translation and spectral dispersion to compress a
multi-spectral, high-speed scene onto a monochrome,
video-rate detector. Single-frame reconstructions of 15
spectral channels and 10 temporal frames are
reported.},
Key = {fds365930}
}
@article{fds280138,
Author = {Marks, DL and Furxhi, O and Brady, DJ},
Title = {W-band imager without mechanical scanning based on an
echelle spectrometer},
Journal = {International Conference on Infrared, Millimeter, and
Terahertz Waves, Irmmw Thz},
Publisher = {IEEE},
Year = {2014},
Month = {November},
ISBN = {9781479938773},
ISSN = {2162-2027},
url = {http://dx.doi.org/10.1109/IRMMW-THz.2014.6956042},
Abstract = {We describe a two-dimensional imager in W-band using a
single heterodyne transceiver and no mechanical scanning. By
using an echelle grating spectrometer, frequencies are
mapped onto a 2-D surface in space, so that spectral
analysis of the signals provides a two-dimensional
image.},
Doi = {10.1109/IRMMW-THz.2014.6956042},
Key = {fds280138}
}
@article{fds280134,
Author = {Marks, DL and Anderson, JG and Phillips, ZF and McCain, ST and Brady,
DJ},
Title = {Gigapixel whole-body microphotography},
Journal = {Frontiers in Optics, Fio 2014},
Year = {2014},
Month = {October},
ISBN = {1557522863},
Abstract = {Time-series whole-body microphotography may potentially be
used for diagnosing skin disease, telemedicine, surgical
field registration, and epidemiological studies. We
demonstrate the technology by imaging a volunteer at 0.25
gigapixel resolution in a snapshot.},
Key = {fds280134}
}
@article{fds350592,
Author = {Marks, DL and Anderson, JG and Phillips, ZF and McCain, ST and Brady,
DJ},
Title = {Gigapixel whole-body microphotography},
Journal = {Frontiers in Optics, Fio 2014},
Year = {2014},
Month = {October},
ISBN = {1557522863},
url = {http://dx.doi.org/10.1364/fio.2014.ftu2f.5},
Abstract = {Time-series whole-body microphotography may potentially be
used for diagnosing skin disease, telemedicine, surgical
field registration, and epidemiological studies. We
demonstrate the technology by imaging a volunteer at 0.25
gigapixel resolution in a snapshot.},
Doi = {10.1364/fio.2014.ftu2f.5},
Key = {fds350592}
}
@article{fds280142,
Author = {Yuan, X and Llull, P and Liao, X and Yang, J and Brady, DJ and Sapiro, G and Carin, L},
Title = {Low-cost compressive sensing for color video and
depth},
Journal = {Proceedings of the Ieee Computer Society Conference on
Computer Vision and Pattern Recognition},
Pages = {3318-3325},
Publisher = {IEEE},
Year = {2014},
Month = {September},
ISBN = {9781479951178},
ISSN = {1063-6919},
url = {http://dx.doi.org/10.1109/CVPR.2014.424},
Abstract = {A simple and inexpensive (low-power and low-bandwidth)
modification is made to a conventional off-the-shelf color
video camera, from which we recover multiple color frames
for each of the original measured frames, and each of the
recovered frames can be focused at a different depth. The
recovery of multiple frames for each measured frame is made
possible via high-speed coding, manifested via translation
of a single coded aperture, the inexpensive translation is
constituted by mounting the binary code on a piezoelectric
device. To simultaneously recover depth information, a
liquid lens is modulated at high speed, via a variable
voltage. Consequently, during the aforementioned coding
process, the liquid lens allows the camera to sweep the
focus through multiple depths. In addition to designing and
implementing the camera, fast recovery is achieved by an
anytime algorithm exploiting the group-sparsity of
wavelet/DCT coefficients.},
Doi = {10.1109/CVPR.2014.424},
Key = {fds280142}
}
@article{fds350829,
Author = {Brady, DJ},
Title = {Compressive millimeter wave and X-ray tomography},
Journal = {Optics Infobase Conference Papers},
Year = {2014},
Month = {January},
ISBN = {9781557523082},
url = {http://dx.doi.org/10.1364/srs.2014.sw1f.1},
Abstract = {Compressive tomography consists of estimation of high
dimensional objects from measurements distributed over lower
dimensions. Examples include reconstruction of 3D spectral
data cubes from 2D focal planes and reconstruction of 3D
volumes from 2D x-ray projections or holograms. Compressive
tomographic estimation is improved if projections are
structured to randomize the sampling phase space. To
illustrate this principle, we show that structured x-ray
illumination enables improvements in reconstructed image
quality for compressed measurements relative to full Radon
sampling and that structured millimeter wave illumination
improves estimation of 3D surfaces. © 2014
OSA.},
Doi = {10.1364/srs.2014.sw1f.1},
Key = {fds350829}
}
@article{fds351292,
Author = {Brady, DJ},
Title = {Roadmap for commercial gigapixel cameras},
Journal = {Optics Infobase Conference Papers},
Year = {2014},
Month = {January},
ISBN = {9781557523082},
url = {http://dx.doi.org/10.1364/aio.2014.aw4a.2},
Abstract = {Multiscale array cameras allow 10-100x improvements in
commercial camera resolution. This talk discussed the
optical manufacturing, electronic processing and
communications and cloud software ecosystem that enables
economical multiscale cameras. © 2014 OSA.},
Doi = {10.1364/aio.2014.aw4a.2},
Key = {fds351292}
}
@article{fds280236,
Author = {Lipworth, G and Hunt, J and Mrozack, A and Brady, D and Smith,
DR},
Title = {Simulations of 2D metamaterial apertures for coherent
computational imaging},
Journal = {2013 Ieee International Conference on Microwaves,
Communications, Antennas and Electronic Systems, Comcas
2013},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISBN = {9781467357562},
url = {http://dx.doi.org/10.1109/COMCAS.2013.6685286},
Abstract = {A metamaterial aperture operating as a leaky waveguide with
resonating metamaterial irises can sweep its operation
frequency to modify its complex field pattern with no moving
parts. By randomly distributing the metamaterials' resonance
frequencies, we show the aperture can generate random
illumination patterns well suited for compressive sensing.
In this way the aperture utilizes the physical layer to
avoid redundant measurements in the image reconstruction
process. © 2013 IEEE.},
Doi = {10.1109/COMCAS.2013.6685286},
Key = {fds280236}
}
@article{fds350830,
Author = {Brady, DJ},
Title = {Compressive tomography},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
ISBN = {9781557529879},
url = {http://dx.doi.org/10.1364/fio.2013.fw4a.5},
Abstract = {Dimension-reducing transformations in geometric, diffractive
and coherence tomography may be coded to improve image
acquisition rate, resolution and feature specificity. We
consider example coding strategies for snapshot (scan-free)
tomography in x-ray, diffraction and video imaging. © 2013
Optical Society of America.},
Doi = {10.1364/fio.2013.fw4a.5},
Key = {fds350830}
}
@article{fds349721,
Author = {Zhu, R and Tsai, TH and Brady, DJ},
Title = {Coded aperture snapshot spectral imager based on liquid
crystal spatial light modulator},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
ISBN = {9781557529879},
url = {http://dx.doi.org/10.1364/fio.2013.fw1d.4},
Abstract = {We describe the use of a liquid crystal on silicon modulator
to jointly code spatial and spectral features for snapshot
spectral imaging. We demonstrate compressive measurement of
megapixel multispectral image with 5 nm resolution. © OSA
2013.},
Doi = {10.1364/fio.2013.fw1d.4},
Key = {fds349721}
}
@article{fds349961,
Author = {Mrozack, A and Heimbeck, M and Marks, DL and Richard, J and Everitt, HO and Brady, DJ},
Title = {Adaptive scanning for synthetic aperture
imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
ISBN = {9781557529879},
url = {http://dx.doi.org/10.1364/fio.2013.fm4i.4},
Abstract = {Synthetic aperture imagers measure the space-bandwidth
product of full-apertures by moving a single detector. We
show results from an adaptive sensing experiment that
demonstrate a three times speedup over full-scans. © 2013
Optical Society of America.},
Doi = {10.1364/fio.2013.fm4i.4},
Key = {fds349961}
}
@article{fds349962,
Author = {Krishnamurthy, K and Mrozack, A and Maggioni, M and Brady,
D},
Title = {Multiscale, dictionary-based speckle denoising},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
ISBN = {9781557529756},
url = {http://dx.doi.org/10.1364/cosi.2013.cm2c.2},
Abstract = {We propose a multiscale, dictionary-based, data-adaptive
estimation method to recover intensities from
multiplicative, speckle data. The proposed method preserves
the edges and textures in the underlying image while
smoothing intensities in homogenous regions. © OSA
2013.},
Doi = {10.1364/cosi.2013.cm2c.2},
Key = {fds349962}
}
@article{fds350189,
Author = {Marks, DL and Brady, DJ},
Title = {A wide-field catadioptric monocentric multiscale telescope
with all-spherical glass optics},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
ISBN = {9781557529756},
url = {http://dx.doi.org/10.1364/isa.2013.itu1e.3},
Abstract = {Monocentric multiscale design combines a common objective
optic with an array of secondary apertures to enable wide
field of view high resolution imaging. Here we describe a
15o field of view with 1.1 arcsecond ifov. © OSA
2013.},
Doi = {10.1364/isa.2013.itu1e.3},
Key = {fds350189}
}
@article{fds350190,
Author = {Vera, E and Golish, D and Gong, Q and Kittle, D and Feller, S and Brady, D and Gehm, M},
Title = {Efficient model-based tonemapping of high dynamic range
gigapixel images},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
ISBN = {9781557529756},
url = {http://dx.doi.org/10.1364/cosi.2013.cm2c.3},
Abstract = {We present a technique to address the tonemapping of high
dynamic range (HDR) gigapixel images. The proposed method
relies on extracting low-dimensional models from
lowresolution proxy images, and can be efficiently
implemented in a parallel manner. © OSA
2013.},
Doi = {10.1364/cosi.2013.cm2c.3},
Key = {fds350190}
}
@article{fds350593,
Author = {Vera, E and Golish, D and Gong, Q and Kelly, K and Kittle, D and Feller, S and Brady, D and Gehm, M},
Title = {Color image formation for multiscale gigapixel
imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
ISBN = {9781557529756},
url = {http://dx.doi.org/10.1364/isa.2013.itu3e.3},
Abstract = {We present the current development of the image formation
pipeline for color gigapixel images obtained by the AWARE-10
multiscale camera.We introduce a camera simulator, the
modifications to the scalable pipeline, and the challenges
for creating seamless color gigapixel panoramas. © 2013
Optical Society of America.},
Doi = {10.1364/isa.2013.itu3e.3},
Key = {fds350593}
}
@article{fds350594,
Author = {Llull, P and Liao, X and Yuan, X and Yang, J and Kittle, D and Carin, L and Sapiro, G and Brady, DJ},
Title = {Compressive sensing for video using a passive coding
element},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
ISBN = {9781557529756},
url = {http://dx.doi.org/10.1364/cosi.2013.cm1c.3},
Abstract = {We present a prototype system that utilizes mechanical
translation of a passive coding element to compress
high-speed temporal information into low-framerate video
sequences. Reconstructions of 148 frames per experimental
coded snapshot are reported. © OSA 2013.},
Doi = {10.1364/cosi.2013.cm1c.3},
Key = {fds350594}
}
@article{fds350595,
Author = {MacCabe, KP and Holmgren, AD and Greenberg, JA and Brady,
DJ},
Title = {Coding for X-ray scatter imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
ISBN = {9781557529756},
url = {http://dx.doi.org/10.1364/cosi.2013.cm4c.2},
Abstract = {We present coding strategies for x-ray scatter imaging, with
focus on pencil and fan beam geometries. Coded apertures
spatially modulate the scatter signal prior to measurement,
and appropriate reconstruction algorithms recover the
tomographic images. © OSA 2013.},
Doi = {10.1364/cosi.2013.cm4c.2},
Key = {fds350595}
}
@article{fds280267,
Author = {Son, HS and Marks, DL and Youn, SH and Brady, DJ and Kim,
J},
Title = {Alignment and assembly strategies for AWARE-10
gigapixel-scale cameras},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8836},
Publisher = {SPIE},
Year = {2013},
ISBN = {9780819496867},
ISSN = {0277-786X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000325488100010&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Gigapixel cameras using lens arrays can contain hundreds to
thousands of precisely positioned optical components and
thus require fast, reliable methods for optical assembly and
alignment verification. Our first one-gigapixel prototype
camera (AWARE-2) and our four-gigapixel camera currently
under development (AWARE-10) need active alignment and
performance measurement procedures during assembly to ensure
high quality images. Here we describe the methods that we
have developed to ensure proper positioning of all optical
components in the AWARE-10 system and the resulting
optomechanical design decisions. AWARE cameras employ a
single monocentric objective lens that is shared by an array
of smaller "micro-cameras", each composed of a set of
smaller scale lenses. In AWARE-10, approximately two
thousand pieces of individual optics must be aligned to a
high level of accuracy in order to attain the desired
optical resolution over four gigapixels. To guarantee proper
alignment before final assembly, the objective lens and the
micro-optics are checked separately. Using tools including
auto-stigmatic microscopy, slanted edge MTF measurements,
and flat field measurements, we can confirm the correct
alignment of individual components before assembly.
Optomechanical designs that incorporate the application of
these alignment tools are described. © 2013 Copyright
SPIE.},
Doi = {10.1117/12.2023370},
Key = {fds280267}
}
@article{fds280139,
Author = {Marks, DL and Brady, DJ and Tremblay, EJ and Ford,
JE},
Title = {Optimizing microcamera aperture in gigapixel monocentric
multiscale cameras},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {January},
ISBN = {9781557529145},
Abstract = {Multiscale designs divide the imaging task between a simple
objective and many complex microcameras. We study imaging
quality as the microcamera aperture size varies from 0.375
to 36 mm with 2 and 50 gigapixel objectives. © 2011 Optical
Society of America.},
Key = {fds280139}
}
@article{fds280140,
Author = {Son, HS and Marks, DL and Tremblay, E and Ford, JE and Hahn, J and Stack,
RA and Johnson, A and McLaughlin, P and Shaw, JM and Kim, J and Brady,
DJ},
Title = {A multiscale, wide field, gigapixel camera},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {January},
ISBN = {9781557529145},
Abstract = {Recent investigations into high pixel count imaging using
multiscale optics have led to a novel optical design for a
wide field, gigapixel camera. We review the mechanical
design and optical performance of this imager. © 2011
OSA.},
Key = {fds280140}
}
@article{fds280141,
Author = {Golish, D and Vera, E and Kelly, K and Gong, Q and Brady, DJ and Gehm,
ME},
Title = {Image formation in multiscale optical systems},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {January},
ISBN = {9781557529145},
Abstract = {We present image formation (IF) strategies developed for
multiscale imaging systems. In this context, IF takes
advantage of significant prior knowledge of array geometry
and relies on parallelizable algorithms to handle the high
data bandwidth. © 2011 OSA.},
Key = {fds280141}
}
@article{fds350831,
Author = {Kittle, D and Zhang, Q and Plemmons, R and Brady, D and Prasad,
S},
Title = {Joint segmentation and reconstruction of coded aperture
hyperspectral data},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {January},
ISBN = {9781557529145},
url = {http://dx.doi.org/10.1364/cosi.2011.cmd1},
Abstract = {This work presents experimental verification of a joint
segmentation reconstruc- tion algorithm on real data from a
snapshot hyperspectral imager. Accurate spectra can be
computed for any pixel location in the data cube. © 2011
Optical Society of America.},
Doi = {10.1364/cosi.2011.cmd1},
Key = {fds350831}
}
@article{fds349963,
Author = {Son, HS and Marks, DL and Tremblay, E and Ford, JE and Hahn, J and Stack,
RA and Johnson, A and McLaughlin, P and Shaw, JM and Kim, J and Brady,
DJ},
Title = {A multiscale, wide field, gigapixel camera},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {January},
ISBN = {9781557529145},
url = {http://dx.doi.org/10.1364/cosi.2011.jtue2},
Abstract = {Recent investigations into high pixel count imaging using
multiscale optics have led to a novel optical design for a
wide field, gigapixel camera. We review the mechanical
design and optical performance of this imager. © 2011
OSA.},
Doi = {10.1364/cosi.2011.jtue2},
Key = {fds349963}
}
@article{fds351293,
Author = {Marks, DL and Brady, DJ and Tremblay, EJ and Ford,
JE},
Title = {Optimizing microcamera aperture in gigapixel monocentric
multiscale cameras},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {January},
ISBN = {9781557529145},
url = {http://dx.doi.org/10.1364/cosi.2011.jtue3},
Abstract = {Multiscale designs divide the imaging task between a simple
objective and many complex microcameras. We study imaging
quality as the microcamera aperture size varies from 0.375
to 36 mm with 2 and 50 gigapixel objectives. © 2011 Optical
Society of America.},
Doi = {10.1364/cosi.2011.jtue3},
Key = {fds351293}
}
@article{fds345484,
Author = {Marks, DL and Brady, DJ},
Title = {Gigagon: A monocentric lens design imaging 40
gigapixels},
Journal = {Optics Infobase Conference Papers},
Year = {2010},
Month = {January},
ISBN = {9781557528926},
Abstract = {The Gigagon is a f/2.5 five element monocentric lens
resolving under 2 arcsec over a 120 degree field of view
intended to image onto megapixel sensors tiled over the
focal surface. © 2010 Optical Society of
America.},
Key = {fds345484}
}
@article{fds350191,
Author = {Guo, J and Leong, HS and Lindquist, RG and Brady,
DJ},
Title = {Integrated nano-hole array surface plasmon resonance
biochemical sensor},
Journal = {Optics Infobase Conference Papers},
Year = {2010},
Month = {January},
url = {http://dx.doi.org/10.1364/fio.2010.fwb7},
Abstract = {We have demonstrated a super-periodic metallic nano-hole
array surface plasmon device for integrated biochemical
sensing. The super-periodic nano-hole array device combines
functions of sensing and surface plasmon resonance spectral
analysis on a single device. © 2010 OSA/FiO/LS
2010.},
Doi = {10.1364/fio.2010.fwb7},
Key = {fds350191}
}
@article{fds351294,
Author = {Fernandez-Cull, C and Brady, D and Wikner, DA and Mait,
JN},
Title = {Sparse fourier sampling in millimeter-wave compressive
holography},
Journal = {Optics Infobase Conference Papers},
Year = {2010},
Month = {January},
ISBN = {9781557528872},
url = {http://dx.doi.org/10.1364/biomed.2010.jma14},
Abstract = {We analyze the impact of sparse sampling on millimeter-wave
(MMW) two-dimensional (2D) holographic measurements for
three-dimensional (3D) object reconstruction. Simulations
address 3D object estimation efficacy. We present 3D object
reconstructions from experimental data. © 2009 Optical
Society of America.},
Doi = {10.1364/biomed.2010.jma14},
Key = {fds351294}
}
@article{fds350832,
Author = {Fernandez-Cull, C and Brady, D and Wikner, DA and Mait,
JN},
Title = {Millimeter-wave imaging using k-space compression},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {January},
ISBN = {9781557528780},
url = {http://dx.doi.org/10.1364/cosi.2009.ctua3},
Abstract = {We apply compression in the spatial frequency domain to
generate millimeter wave images. Simulations indicate the
efficacy of the approach. We are in the process of testing
the system experimentally. © 2009 Optical Society of
America.},
Doi = {10.1364/cosi.2009.ctua3},
Key = {fds350832}
}
@article{fds350192,
Author = {Brady, DJ},
Title = {Multiscale optical systems},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {January},
ISBN = {9781557528780},
url = {http://dx.doi.org/10.1364/cosi.2009.cwb2},
Abstract = {Cameras capturing gigapixel or even terapixel images are
enabled by lens systems combining single aperture objectives
with arrays of smaller scale processing optics. © 2009
Optical Society of America.},
Doi = {10.1364/cosi.2009.cwb2},
Key = {fds350192}
}
@article{fds350596,
Author = {Choi, K and Horisaki, R and Marks, DL and Brady, DJ},
Title = {Coding and signal inference in compressive
holography},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {January},
ISBN = {9781557528780},
url = {http://dx.doi.org/10.1364/cosi.2009.ctha5},
Abstract = {Compressive sensing enables highly accurate signal
reconstruction from fewer measurements than the number of
samples in a signal to be estimated. This paper describes a
theoretical framework for 3D tomographic reconstruction from
2D holographic measurements. © 2009 Optical Society of
America.},
Doi = {10.1364/cosi.2009.ctha5},
Key = {fds350596}
}
@article{fds351295,
Author = {Hagen, N and Brady, DJ},
Title = {Aberration correction in multiscale lenses},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {January},
ISBN = {9781557528780},
url = {http://dx.doi.org/10.1364/cosi.2009.cwb4},
Abstract = {Multiscale lens design splits the field into subregions and
attempts to correct the local wavefront error in each
subfield rather than the global error. We review the
aberration theory underlying the approach. © 2009 Optical
Society of America.},
Doi = {10.1364/cosi.2009.cwb4},
Key = {fds351295}
}
@article{fds351296,
Author = {Lim, S and Horisaki, R and Choi, K and Marks, DL and Brady,
DJ},
Title = {Experimental demonstrations of compressive
holography},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {January},
ISBN = {9781557528780},
url = {http://dx.doi.org/10.1364/cosi.2009.ctha6},
Abstract = {We demonstrate 3D object reconstruction from a single 2D
data plane using compressive holography in Gabor and
Leith-Upatneiks geometries. © 2009 Optical Society of
America.},
Doi = {10.1364/cosi.2009.ctha6},
Key = {fds351296}
}
@article{fds351297,
Author = {Portnoy, AD and Brady, DJ},
Title = {Quantitative performance metrics with long wave infrared
multiple aperture cameras},
Journal = {Optics Infobase Conference Papers},
Year = {2008},
Month = {January},
ISBN = {9781557528612},
url = {http://dx.doi.org/10.1364/fio.2008.fthf7},
Abstract = {We characterize a long wave infrared multiple aperture
imaging system by experimentally measuring its Noise
Equivalent Temperature Difference and modulation transfer
function. These results are compared with a conventional
system. © 2008 Optical Society of America.},
Doi = {10.1364/fio.2008.fthf7},
Key = {fds351297}
}
@article{fds330744,
Author = {Linnehan, R and Schindler, J and Brady, D and Kozma, R and Deming, R and Perlovsky, L},
Title = {Resolving wall ambiguities using angular diverse synthetic
arrays},
Journal = {Ieee International Conference on Neural Networks Conference
Proceedings},
Pages = {2758-2763},
Publisher = {IEEE},
Year = {2007},
Month = {December},
ISBN = {142441380X},
url = {http://dx.doi.org/10.1109/IJCNN.2007.4371395},
Abstract = {Model-based algorithms that attempt to localize targets and
estimate the structure within a building using data from
external sensors have received much attention in recent
years. The potential benefits to homeland security and urban
warfare are exceedingly apparent. Accurately estimating the
thickness and dielectric constant of the exterior wall could
prove to be a critical first step in determining the layout
within, i.e., the location of interior walls, doorways,
stairwells, etc. However, data collection using a linear
sensor arrangement yields an ambiguous two dimensional
objective function for the wall parameters, rendering
maximum likelihood methods ineffective. We show that a
spatially diverse aperture obviates the wall parameter
ambiguity and allows accurate estimation of thickness and
permittivity using dynamic logic, an iterative model-based
approach to maximum likelihood. ©2007 IEEE.},
Doi = {10.1109/IJCNN.2007.4371395},
Key = {fds330744}
}
@article{fds330745,
Author = {Linnehan, R and Schindler, J and Brady, D and Kozma, R and Deming, R and Perlovsky, L},
Title = {Dynamic logic applied to SAR data for parameter estimation
behind walls},
Journal = {Ieee National Radar Conference Proceedings},
Pages = {850-855},
Publisher = {IEEE},
Year = {2007},
Month = {September},
ISBN = {1424402840},
url = {http://dx.doi.org/10.1109/RADAR.2007.374331},
Abstract = {Identifying and localizing targets within buildings using
exterior sensors will offer superior advantages to the
military and law enforcement communities. Research on
wall-penetrating radar has produced significant advances in
recent years regarding this topic. However, wall parameter
ambiguities, multiple reflections, clutter, and measurement
noise pose significant challenges to developing robust
detection and estimation methods. In the present work we
demonstrate can be mitigated using dynamic logic (DL), an
adaptive method for iterative maximum likelihood. © 2007
IEEE.},
Doi = {10.1109/RADAR.2007.374331},
Key = {fds330745}
}
@article{fds280136,
Author = {Willett, RM and Gehm, ME and Brady, DJ and John, R},
Title = {Compressive spectral imaging and multiscale reconstruction
methods},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISBN = {1557528381},
Abstract = {In this work we develop a single-shot, dual-disperser
spectral imaging system and associated multiscale
photon-limited multispectral reconstruction methods that
have been designed to exploit the emerging theory of
compressive sensing. © 2007 Optical Society of
America.},
Key = {fds280136}
}
@article{fds350833,
Author = {Pitsianis, NP and Brady, DJ and Sun, X},
Title = {The MONTAGE least gradient image reconstruction},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISBN = {1557528381},
url = {http://dx.doi.org/10.1364/cosi.2007.ctub3},
Abstract = {We introduce an image reconstruction algorithm for the
Compressive Optical MONTAGE Photography Initiative, for
recovering the resolution of an image from a set of aliased
subimages acquired by a lenslet array optical system. ©
2007 Optical Society of America.},
Doi = {10.1364/cosi.2007.ctub3},
Key = {fds350833}
}
@article{fds350834,
Author = {Portnoy, A and Shankar, M and Pitsianis, N and Brady, D and Gibbons, R and Silver, A and Keller, D and Chen, C and Prather, D},
Title = {Depth of field with multi-aperture LWIR imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISBN = {1557528462},
url = {http://dx.doi.org/10.1364/fio.2007.fthq1},
Abstract = {We use a multiaperture approach to design a thin LWIR
camera. Having a shorter focal length, the microlens array
provides an extended depth of field over the conventional
system. © 2007 Optical Society of America.},
Doi = {10.1364/fio.2007.fthq1},
Key = {fds350834}
}
@article{fds349723,
Author = {Brady, DJ},
Title = {Multidimensional spatial and coherence imaging using single
shot spectral imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISBN = {1557528381},
url = {http://dx.doi.org/10.1364/srs.2007.smb3},
Abstract = {A spectral imaging system may efficiently sense 10-100
spectral channels but the full data cube is often redundant.
We propose to exploit this redundancy to computationally
expand depth of field or obtain multidimensional spatial
images. © 2007 Optical Society of America.},
Doi = {10.1364/srs.2007.smb3},
Key = {fds349723}
}
@article{fds349722,
Author = {Badieirostami, M and Momtahan, O and Hsieh, CR and Adibi, A and Brady,
DJ},
Title = {An ultra-high resolution volume holographic
spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISBN = {1557528462},
url = {http://dx.doi.org/10.1364/fio.2007.fwh2},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a cylindrical beam volume
hologram. The combination of these two elements results in a
twodimensional spatial-spectral mapping in the output plane.
Using this spectrometer, ultra-high resolution (better than
0.2 nm) over a large bandwidth has been experimentally
demonstrated for diffuse light sources. © 2007 Optical
Society of America.},
Doi = {10.1364/fio.2007.fwh2},
Key = {fds349722}
}
@article{fds350597,
Author = {Shankar, M and Pitsianis, N and Sun, X and Brady,
D},
Title = {Compressive measurements for video},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISBN = {1557528462},
url = {http://dx.doi.org/10.1364/fio.2007.fmj4},
Abstract = {Redundancies present in video streams could be used to
implement compressive sampling to achieve low power video
sensors. We explore the possibilities of using this in the
design of compressive video sensors and corresponding
algorithms. © 2007 Optical Society of America.},
Doi = {10.1364/fio.2007.fmj4},
Key = {fds350597}
}
@article{fds350598,
Author = {Willett, RM and Gehm, ME and Brady, DJ and John, R},
Title = {Compressive spectral imaging and multiscale reconstruction
methods},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISBN = {1557528381},
url = {http://dx.doi.org/10.1364/srs.2007.smb4},
Abstract = {In this work we develop a single-shot, dual-disperser
spectral imaging system and associated multiscale
photon-limited multispectral reconstruction methods that
have been designed to exploit the emerging theory of
compressive sensing. © 2007 Optical Society of
America.},
Doi = {10.1364/srs.2007.smb4},
Key = {fds350598}
}
@article{fds351298,
Author = {Badieirostami, M and Momtahan, O and Hsieh, CR and Eftekhar, AA and Adibi, A and Brady, DJ},
Title = {An ultra-high resolution tandem fabry-perot etalon
cylindrical beam volume hologram spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISBN = {1557528381},
url = {http://dx.doi.org/10.1364/cosi.2007.cmc3},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a cylindrical beam volume
hologram. The combination of these two elements results in a
twodimensional spatial-spectral mapping in the output plane.
Using this spectrometer, ultra-high resolution (better than
0.2 nm) over a large bandwidth has been experimentally
demonstrated for diffuse light sources. © 2007 Optical
Society of America.},
Doi = {10.1364/cosi.2007.cmc3},
Key = {fds351298}
}
@article{fds351299,
Author = {McCain, ST and Willett, RM and Brady, DJ},
Title = {Coded-excitation Raman spectroscopy for Raman signal
estimation in highly fluorescent media},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISBN = {1557528381},
url = {http://dx.doi.org/10.1364/cosi.2007.cmc4},
Abstract = {Raman signal estimation in highly fluorescent media is
investigated using multiple excitation lasers and an
iterative EM spectral reconstruction algorithm. Results from
an 8-laser system show estimation performance increases with
the number of excitation lasers. © 2007 Optical Society of
America.},
Doi = {10.1364/cosi.2007.cmc4},
Key = {fds351299}
}
@article{fds351300,
Author = {Mahalanobis, A and Neifeld, M and Kumar, BVKV and Brady, D and Haberfelde, T and Muise, R},
Title = {Multiplexed point spread functions for image formation with
application to large area sensing and surveillance},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISBN = {1557528381},
url = {http://dx.doi.org/10.1364/cosi.2007.ptua4},
Doi = {10.1364/cosi.2007.ptua4},
Key = {fds351300}
}
@article{fds323402,
Author = {Brady, DJ and Gehm, M and McCain, S and Guenther, B and Pitsianis, N and Adibi, A},
Title = {Integrated sensing and processing of Raman spectra for in
vivo BAC measurement},
Journal = {Alcoholism, Clinical and Experimental Research},
Volume = {30},
Number = {6},
Pages = {274A-274A},
Publisher = {BLACKWELL PUBLISHING},
Year = {2006},
Month = {June},
Key = {fds323402}
}
@article{fds350835,
Author = {Shankar, M and Willett, R and Pitsianis, N and Brady, D and Schulz, T and Gibbons, B and Te Kolste and B and Carriere, J and Chen,
C},
Title = {Ultra-thin multi-aperture LWIR imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
ISBN = {1557528187},
url = {http://dx.doi.org/10.1364/fio.2006.fwn6},
Abstract = {We design and implement an ultra-thin LWIR camera by
replacing the conventional lens system with a micro-lens
array. The resulting low resolution images can be used to
reconstruct a high resolution image by post processing. ©
2006 Optical Society of America.},
Doi = {10.1364/fio.2006.fwn6},
Key = {fds350835}
}
@article{fds350836,
Author = {Badieirostami, M and Momtahan, O and Adibi, A and Brady,
DJ},
Title = {A compact Fabry-Perot grating cascaded spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
ISBN = {1557528187},
url = {http://dx.doi.org/10.1364/fio.2006.jwd16},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a grating. The grating expands
the limited spectral range of the Fabry-Perot and the
combination of both elements results in a powerful
spectrometer with good two-dimensional spatial-spectral
diversity in the output plane. © 2006 Optical Society of
America.},
Doi = {10.1364/fio.2006.jwd16},
Key = {fds350836}
}
@article{fds350837,
Author = {Brady, DJ},
Title = {Compressive sampling in spectral imaging
systems},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
ISBN = {1557528187},
url = {http://dx.doi.org/10.1364/fio.2006.fmb1},
Abstract = {Optical prefilters shape the analog-digital interface in
imaging systems to implement generalized spatio-spectral
sampling. The Duke Imaging and Spectroscopy Program explores
generalized sampling systems, this talk focuses specifically
on spectral encoding for compressive spatial imaging. ©
2005 Optical Society of America.},
Doi = {10.1364/fio.2006.fmb1},
Key = {fds350837}
}
@article{fds350193,
Author = {Guo, J and Wang, G and Brady, DJ},
Title = {Super-resolution mapping of flow velocity distribution in
nanofluidic channels},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
ISBN = {1557528187},
url = {http://dx.doi.org/10.1364/fio.2006.jwh4},
Abstract = {We will show a super-resolution mapping technique for
measuring the flow velocity distribution in nanofluidic
channels. The mapping resolution can be much smaller than
the diffraction limit of the optical imaging system. © 2006
Optical Society of America.},
Doi = {10.1364/fio.2006.jwh4},
Key = {fds350193}
}
@article{fds350599,
Author = {McCain, ST and Willett, R and Brady, DJ},
Title = {Coded-excitation Raman spectroscopy for ethanol chemometrics
of tissue},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
ISBN = {1557528187},
url = {http://dx.doi.org/10.1364/fio.2006.ftuk5},
Abstract = {Raman spectroscopy of bulk tissue is challenging due to
sample auto-fluorescence and weak Raman cross-sections of
most molecules. We investigate the use of coded-excitation
Raman spectroscopy coupled with an iterative algorithm for
Raman signal estimation. © 2006 Optical Society of
America.},
Doi = {10.1364/fio.2006.ftuk5},
Key = {fds350599}
}
@article{fds365931,
Author = {Guo, J and Wang, G and Brady, DJ},
Title = {Super-resolution Mapping of Flow Velocity Distribution in
Nanofluidic Channels},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
ISBN = {9781557528209},
Abstract = {We will show a super-resolution mapping technique for
measuring the flow velocity distribution in nanofluidic
channels. The mapping resolution can be much smaller than
the diffraction limit of the optical imaging
system.},
Key = {fds365931}
}
@article{fds365932,
Author = {Badieirostami, M and Momtahan, O and Adibi, A and Brady,
DJ},
Title = {A Compact Fabry-Perot Grating Cascaded Spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
ISBN = {9781557528209},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a grating. The grating expands
the limited spectral range of the Fabry-Perot and the
combination of both elements results in a powerful
spectrometer with good two-dimensional spatial-spectral
diversity in the output plane.},
Key = {fds365932}
}
@article{fds365933,
Author = {Fernandez, C and Guenther, BD and Gehm, ME and Brady, DJ and Sullivan,
ME},
Title = {Longwave Infrared (LWIR) Coded Aperture Dispersive
Spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
ISBN = {9781557528209},
Abstract = {We describe a static aperture-coded, dispersive longwave
infrared (LWIR) spectrometer that uses a microbolometer
array as the detector plane. We present experimental results
of absorption spectroscopy for a variety of
sources.},
Key = {fds365933}
}
@article{06239919406,
Author = {Linnehan, R and Brady, D and Schindler, J and Perlovsky, L and Rangaswamy, M},
Title = {Using Cramér-Rao theory for multiple agents},
Journal = {2005 International Conference on Integration of Knowledge
Intensive Multi Agent Systems, Kimas'05: Modeling,
Exploration, and Engineering},
Volume = {2005},
Pages = {444-448},
Publisher = {IEEE},
Address = {Milan, Italy},
Year = {2005},
Month = {December},
ISBN = {078039013X},
url = {http://dx.doi.org/10.1109/KIMAS.2005.1427122},
Keywords = {Synthetic aperture radar;Algorithms;Signal
processing;Parameter estimation;Signal receivers;Computational
complexity;},
Abstract = {This paper develops Cramér-Rao theory for multi-agent
system design. We apply Cramér-Rao theory to synthetic
aperture radar (SAR) in order to establish optimal
performance bounds that are independent from signal
processing algorithms. Bounds on the estimation of various
target parameters are developed, and the extension to
multiple receivers is considered. © 2005
IEEE.},
Doi = {10.1109/KIMAS.2005.1427122},
Key = {06239919406}
}
@article{fds350838,
Author = {Gehm, ME and McCain, ST and Wang, Y and Pitsianis, NP and Brady,
DJ},
Title = {Multimodal, multiplex Raman spectrometer for weak,
incoherent sources},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {155752789X},
url = {http://dx.doi.org/10.1364/cosi.2005.ctuc2},
Abstract = {Raman spectroscopy in bio-materials is complicated by
fluorescence and scattering. We have developed a multimodal,
multiplex spectrometer that overcomes these difficulties. We
are currently constructing a second generation prototype for
in-vivo Raman spectroscopy of tissue. © 2005 Optical
Society of America.},
Doi = {10.1364/cosi.2005.ctuc2},
Key = {fds350838}
}
@article{fds350839,
Author = {Fiddy, MA and Suleski, TJ and Brady, DJ and Pitsianis,
NP},
Title = {Compressive sampling for feature specific compact
imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {1557527970},
url = {http://dx.doi.org/10.1364/fio.2005.fwu4},
Abstract = {We investigate the use of estimation methods with
multi-aperture imaging hardware that are noise robust and
able to provide high resolution images from limited
measurements. © 2005 Optical Society of
America.},
Doi = {10.1364/fio.2005.fwu4},
Key = {fds350839}
}
@article{fds350840,
Author = {Portnoy, AD and Guo, J and Pitsianis, NP and Guenther, B and Brady, DJ and Te Kolste and RD and Feldman, MR and Fiddy, MA and Suleski,
TJ},
Title = {Multi-aperture visible high resolution thin
imager},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {1557527970},
url = {http://dx.doi.org/10.1364/fio.2005.fwu2},
Abstract = {We have designed and built a multi-aperture thin imager
using a lenslet array and a CCD imager. The thickness of the
imager is significantly reduced. We will present
experimental results that demonstrate high resolution
imaging. © 2005 Optical Society of America.},
Doi = {10.1364/fio.2005.fwu2},
Key = {fds350840}
}
@article{fds350841,
Author = {Pitsianis, NP and Brady, DJ and Sun, X},
Title = {The quantized cosine transform for sensor-layer image
compression},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {155752789X},
url = {http://dx.doi.org/10.1364/cosi.2005.jma4},
Abstract = {We introduce a compressive encoding at the sensor layer
based on the quantized cosine transform. Compression at the
physical layer of integrated imaging systems reduces the
measurements-to-pixels ratio, the data volume and
accelerates image estimation. © 2005 Optical Society of
America.},
Doi = {10.1364/cosi.2005.jma4},
Key = {fds350841}
}
@article{fds350842,
Author = {Hsieh, C and Momtahan, O and Karbaschi, A and Adibi, A and Brady,
DJ},
Title = {Compact spectral diversity filters for diffuse source
spectroscopy using spherical beam volume
holograms},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {155752789X},
url = {http://dx.doi.org/10.1364/cosi.2005.ctuc5},
Abstract = {We describe a new class of compact spectral diversity
filters implemented using spherical beam volume holograms.
Spectral diversity is improved by rotation multiplexing
technique. Diffuse source spectroscopy enabled by using
Fourier transform architecture is demonstrated. © 2005
Optical Society of America.},
Doi = {10.1364/cosi.2005.ctuc5},
Key = {fds350842}
}
@article{fds350843,
Author = {Brady, DJ and Fiddy, MA and Shahid, U and Suleski,
TJ},
Title = {Compressive optical MONTAGE photography initiative: Noise
and error analysis},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {155752789X},
url = {http://dx.doi.org/10.1364/cosi.2005.cmb3},
Abstract = {Image resolution is usually considered to be proportional to
the focal plane sampling rate. However, as a result of
Papoulis's generalized sampling theory [1], it is possible
to reconstruct bandlimited images from sub-Nyquist sampled
data provided multiple channels of such data are measured,
with each set suitably transformed to permit the computation
of the original image. The COMP-I program uses focal plane
coding to set sub-band sampling characteristics. Analysis
and simulation of this approach to errors and noise is
presented. © 2005 Optical Society of America.},
Doi = {10.1364/cosi.2005.cmb3},
Key = {fds350843}
}
@article{fds323553,
Author = {Portnoy, AD and Guo, JP and Brady, DJ},
Title = {Super-resolved point source tracking using birefringent
impulse response coding},
Journal = {Proceedings of the 8th Joint Conference on Information
Sciences, Vols 1 3},
Pages = {1327-1329},
Publisher = {JOINT CONFERENCE INFORMATION SCIENCES},
Editor = {Blair, S and Chakraborty, U and Chen, SH and Cheng, HD and Chiu, DKY and Das, S and Denker, G and Duro, R and Romay, MG and Hung, D and Kerre, EE and VaLeong, H and Lu, CT and Lu, J and Maguire, L and Ngo, CW and Sarfraz, M and Tseng, C and Tsumoto, S and Ventura, D and Wang, PP and Yao, X and Zhang,
CN and Zhang, K},
Year = {2005},
Month = {January},
Key = {fds323553}
}
@article{fds323554,
Author = {McCain, ST and Gehm, ME and Wang, Y and Pitsianis, NP and Brady,
DJ},
Title = {Coded-aperture, multi-wavelength Raman spectroscopy for
ethanol detection in biological samples},
Journal = {Proceedings of the 8th Joint Conference on Information
Sciences, Vols 1 3},
Pages = {1385-1388},
Publisher = {JOINT CONFERENCE INFORMATION SCIENCES},
Editor = {Blair, S and Chakraborty, U and Chen, SH and Cheng, HD and Chiu, DKY and Das, S and Denker, G and Duro, R and Romay, MG and Hung, D and Kerre, EE and VaLeong, H and Lu, CT and Lu, J and Maguire, L and Ngo, CW and Sarfraz, M and Tseng, C and Tsumoto, S and Ventura, D and Wang, PP and Yao, X and Zhang,
CN and Zhang, K},
Year = {2005},
Month = {January},
Key = {fds323554}
}
@article{fds330749,
Author = {Linnehan, R and Brady, D and Schindler, J and Perlovsky, L and Rangaswamy, M},
Title = {Using Cramér-Rao theory for SAR waveform
design},
Journal = {Ieee National Radar Conference Proceedings},
Volume = {2005-January},
Number = {January},
Pages = {217-221},
Publisher = {IEEE},
Year = {2005},
Month = {January},
ISBN = {078038881X},
url = {http://dx.doi.org/10.1109/RADAR.2005.1435822},
Abstract = {This paper applies Cramér-Rao theory to synthetic aperture
radar (SAR) in order to establish optimal performance bounds
on target parameter estimation. The Cramér-Rao bound (CRB)
establishes a lower bound on the error variance of unbiased
or asymptotically efficient parameter estimates (L.L.
Scharf, 1991). Bounds on the estimation of various target
parameters are developed, and the extension to multistatic
SAR (MSAR) is considered.},
Doi = {10.1109/RADAR.2005.1435822},
Key = {fds330749}
}
@article{fds349724,
Author = {Mait, JN and Prather, DW and Brady, DJ},
Title = {Diffractive generation of non-redundant images for a
multi-aperture, thin, high-resolution camera},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {155752789X},
url = {http://dx.doi.org/10.1364/cosi.2005.cmc2},
Abstract = {We have designed a diffractive element capable of generating
shift-encoded images for a thin, multiplexed optical imaging
system. We present simulations that validate the use of the
element for high resolution imaging and preliminary
experimental results of diffractive image replication. ©
2005 Optical Society of America.},
Doi = {10.1364/cosi.2005.cmc2},
Key = {fds349724}
}
@article{fds350194,
Author = {Guo, J and Portnoy, A and Brady, DJ},
Title = {Diffraction-limited impulse response image reconstruction
with a single imaging pixel},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {155752789X},
url = {http://dx.doi.org/10.1364/cosi.2005.jtua5},
Abstract = {In this paper, we will discuss two techniques to reconstruct
diffraction-limited impulse response images by sub-pixel
shifting the photodetector array and measuring the signal
from a specific large area photodetector pixel. © 2005
Optical Society of America.},
Doi = {10.1364/cosi.2005.jtua5},
Key = {fds350194}
}
@article{fds350195,
Author = {Shankar, M and Jones, DB and Swagart, RG and Burchett, JB and Guenther,
BD and Feller, SD and Brady, DJ},
Title = {Large area pyroelectric motion tracking system},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {155752789X},
url = {http://dx.doi.org/10.1364/cosi.2005.ctuc6},
Abstract = {Simple pyroelectric detectors and structured apertures are
used to monitor motion in an area and report location and
velocity of objects moving through the monitored area. ©
2005 OSA/COSI 2005.},
Doi = {10.1364/cosi.2005.ctuc6},
Key = {fds350195}
}
@article{fds350957,
Author = {Peters, AE and Gehm, ME and Guenther, BD and Brady,
DJ},
Title = {Multiplex design for high-performance microspectrometers},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {155752789X},
url = {http://dx.doi.org/10.1364/cosi.2005.ctuc4},
Abstract = {The volume of spectrometers can be drastically reduced
through the use of multiplex measurement. Reductions of 3-5
orders of magnitude are possible. This has the potential to
drastically effect manufacturing and deployment costs.
©2005 Optical Society of America.},
Doi = {10.1364/cosi.2005.ctuc4},
Key = {fds350957}
}
@article{fds351301,
Author = {Shankar, M and Burchett, JB and Feller, SD and Guenther, BD and Brady,
DJ},
Title = {Human motion tracking system using coded Fresnel lens
arrays},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {1557527970},
url = {http://dx.doi.org/10.1364/fio.2005.ftum6},
Abstract = {We have designed and developed a low-cost human motion
tracking system using pyroelectric detectors and coded
Fresnel lens arrays. We have deployed sensor clusters
implementing an 8x8 Hadamard code variant and will
demonstrate motion tracking. © 2005 Optical Society of
America.},
Doi = {10.1364/fio.2005.ftum6},
Key = {fds351301}
}
@article{fds351302,
Author = {Gibbons, RC and Gilstrap, JA and Mait, JN and Prather, DW and Guo, J and Brady, DJ},
Title = {Design of a thin multi-aperture infrared
imager},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISBN = {1557527970},
url = {http://dx.doi.org/10.1364/fio.2005.fthu6},
Abstract = {We have designed a thin, multiplexed infrared imaging system
that uses a diffractive element for generating shift-encoded
images in each aperture. We present preliminary experimental
results that demonstrate imager performance. © 2005 Optical
Society of America.},
Doi = {10.1364/fio.2005.fthu6},
Key = {fds351302}
}
@article{fds330750,
Author = {Bouchereau, F and Brady, D},
Title = {Bounds on range-resolution degradation using RSSI
measurements},
Journal = {Ieee International Conference on Communications},
Volume = {6},
Pages = {3246-3250},
Year = {2004},
Month = {January},
url = {http://dx.doi.org/10.1109/icc.2004.1313145},
Abstract = {In this paper, we investigate the fundamental loss of
ranging resolution using received signal strength indicator
(RSSI) observations relative to unprocessed received signal
(URS) measurements. Unlike previous work, this is done for a
single propagation model that accounts for large-scale
(log-normal) fading and small-scale (multipath) fading
effects. Further, this contribution fully accounts for the
temporal correlation of the log-normal attenuation and the
multipath channel, which previous work has ignored. Cramer
Rao bounds on the estimates of range will give us a complete
description of the effects of data reduction (through RSSI
observations), multipath, and random attenuation on the
estimates of range.},
Doi = {10.1109/icc.2004.1313145},
Key = {fds330750}
}
@article{fds364318,
Author = {Momtahan, O and Hsieh, CR and Momeni, B and Adibi, A and Brady,
DJ},
Title = {Modeling and Experimental Characterizing the Filter Function
of Holographic Spectral Diversity Filters for Multimodal
Multiplex Spectroscopy},
Journal = {Optics Infobase Conference Papers},
Year = {2004},
Month = {January},
ISBN = {9781557528209},
Abstract = {We propose an analytical solution based on
Born-approximation for diffraction analysis of relatively
strong multiplexed holograms. The direct application of this
method is designing holograms for multimodal multiplex
spectroscopy (MMS) applications. The filter function of
holographic MMS is modeled using this method and compared
with the experimental results.},
Key = {fds364318}
}
@article{fds364317,
Author = {Gehm, ME and McCain, ST and Sullivan, ME and Brady,
DJ},
Title = {Static, multimodal, multiplex spectrometer design for weak,
incoherent sources},
Journal = {Optics Infobase Conference Papers},
Year = {2004},
Month = {January},
ISBN = {9781557528209},
Abstract = {We present a flexible design for a static, multimodal,
multiplex spectrometer which is optimized for the weak
incoherent sources that are common in biomedical
applications. Simultaneous high throughput and resolution
are achieved in a single-shot measurement via 2-D aperture
encoding. The resulting computational problem is
well-conditioned and easily invertible.},
Key = {fds364317}
}
@article{fds364319,
Author = {Hsieh, C and Momtahan, O and Karbaschi, A and Adibi, A and Sullivan, ME and Brady, DJ},
Title = {Implementation of Efficient Fourier-transform Holographic
Spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2004},
Month = {January},
ISBN = {9781557528209},
Abstract = {We present the first implementation of a Fourier-transform
spherical beam holographic spectrometer with considerably
better sensitivity compared to conventional grating
spectrometers. We use this idea to demonstrate a compact
spectrometer that is usually encountered in optical sensing
with great potential for measuring weak spatially incoherent
signal.},
Key = {fds364319}
}
@article{fds364320,
Author = {McCain, ST and Gehm, ME and Wang, L and Xu, Z and Sullivan, ME and Brady,
DJ},
Title = {Multimodal, multiplex Raman spectrometry for detection of
ethanol in blood and tissue},
Journal = {Optics Infobase Conference Papers},
Year = {2004},
Month = {January},
ISBN = {9781557528209},
Abstract = {We investigate the application of static, multimodal,
multiplex spectrometers to the detection of the Raman
spectrum of ethanol in blood and tissue. These spectrometers
are optimized for use with weak, incoherent sources, and
enable relatively high sensitivity in a completely
integrated system.},
Key = {fds364320}
}
@article{fds364321,
Author = {Zheng, Y and Brady, DJ and Guenther, BD and Pitsianis,
NP},
Title = {Fiber optical web for object localization by geometric space
coding},
Journal = {Optics Infobase Conference Papers},
Year = {2004},
Month = {January},
ISBN = {9781557528209},
Abstract = {A fiber web was used for object(s) localization. The fiber
web used binary codes to segment and encode the object
space. We employed 2D gray code to localize an extended
object and superimposed code to localize multiple objects
simultaneously. Experimental human localization systems with
both coding scheme were demonstrated.},
Key = {fds364321}
}
@article{fds364322,
Author = {Shankar, M and Hao, Q and Burchett, J and Brady, DJ},
Title = {Visibility modulation using Reference Structures for human
motion tracking},
Journal = {Optics Infobase Conference Papers},
Year = {2004},
Month = {January},
ISBN = {9781557528209},
Key = {fds364322}
}
@article{fds330751,
Author = {Bouchereau, F and Brady, D},
Title = {Bounds on wireless location estimation of mobile
transmitters in a time varying acoustic underwater
channel},
Journal = {Oceans Conference Record (Ieee)},
Volume = {1},
Pages = {6},
Year = {2003},
Month = {December},
Abstract = {Wireless localization of multiple mobile underwater
transmitters becmae a very important area of research.
Several solutions to the underwater localization problem
consider the measurement of the first time of arrival of a
signal coming from a node with unknown location and arriving
at a receiver with known location. This allows the
estimation of distance between them and eventually, the
estimation of the node location by triangulation.},
Key = {fds330751}
}
@article{8254881,
Author = {Reid, CM and Badieirostami, M and Jafarpour, A and Alibi, A and Sullivan, ME and Brady, DJ},
Title = {Design and analysis of photonic crystal spectral diversity
filters for biosensing},
Journal = {Optics Infobase Conference Papers},
Volume = {vol.2},
Pages = {2 pp. vol.2 -},
Address = {San Francisco, CA, USA},
Year = {2003},
Month = {January},
ISBN = {9781557528209},
Keywords = {biological techniques;optical design techniques;optical
filters;optical sensors;photonic crystals;Raman
spectra;},
Abstract = {We present a systematic method for designing spectral
diversity filters using 2D and 3D photonic crystals. These
filters convert an incoherent input beam with uniform
spectral content over the input dimension into a desired
nonuniform spatial-spectral pattern. Such spectral diversity
filters can be used for designing compact spectrometers that
can be used for the detection of Raman signatures in
biosensors},
Key = {8254881}
}
@article{fds364324,
Author = {Gopinathan, U and Shankar, M and Pitsianis, N and Brady,
DJ},
Title = {Efficient motion sensing system using pyroelectric
sensors},
Journal = {Optics Infobase Conference Papers},
Year = {2003},
Month = {January},
ISBN = {9781557528209},
Abstract = {We describe a motion sensor system that can discriminate 'N'
source states using logarithm of 'N' sensor measurements.
Based on this design approach, we implement a motion sensing
system using pyroelectric sensors as the sensing element and
a reference structure based optical element.},
Key = {fds364324}
}
@article{fds364325,
Author = {Potuluri, P and Xu, M and Brady, DJ},
Title = {Three dimensional imaging using reference
structures},
Journal = {Optics Infobase Conference Papers},
Year = {2003},
Month = {January},
ISBN = {9781557528209},
Abstract = {We describe an imaging system based on a novel volume
optical element, a tomographic reference structure, which
implements a mapping from a three dimensional source volume
on to a two dimensional sensor plane. We show how reference
structures spatially segment a three dimensional source
volume and present some results.},
Key = {fds364325}
}
@article{fds364326,
Author = {Hsieh, C and Karbaschi, A and Momtahan, O and Adibi, A and Brady,
DJ},
Title = {Accurate design and analysis of spherical beam volume
holograms for sensing applications},
Journal = {Optics Infobase Conference Papers},
Year = {2003},
Month = {January},
ISBN = {9781557528209},
Abstract = {We present an accurate model for design and analysis of
volume holograms recorded by spherical reference beams. We
explain how it can be used for analysis of incoherent Raman
signals in bio and environmental sensing. For such
applications, conventional models based on paraxial
approximations must be replaced by accurate
model.},
Key = {fds364326}
}
@article{fds364327,
Author = {Zheng, Y and Sullivan, M and Brady, D},
Title = {Differential tracking system by geometrical segmentation of
source space with coded laser beams},
Journal = {Optics Infobase Conference Papers},
Year = {2003},
Month = {January},
ISBN = {9781557528209},
Abstract = {We describe a differential tracking system (DTS) based on
differential pulse code modulation channel. A laser beam web
is employed to segment and differentiate the source space
and measure the quantized source velocity vector. DTS can
track a source in N position with only O(1) sensors in each
dimension.},
Key = {fds364327}
}
@article{fds365611,
Author = {Cull, E and Sullivan, M and Brady, D},
Title = {Target estimation from interferometric tracking
telescopes},
Journal = {Optics Infobase Conference Papers},
Year = {2003},
Month = {January},
ISBN = {1557527504},
Abstract = {Joint target triangulation and estimation from
spatio-spectral tracking using a rotational shear
interferometer on a telescope is described. The system is
based on an array of three eight inch off-axis parabolic
reflector telescopes with CCD cameras used for
imaging.},
Key = {fds365611}
}
@article{8126136,
Author = {Potuluri, P and Brady, DJ},
Title = {3D spatial segmentation using reference structures},
Journal = {Optics Infobase Conference Papers},
Pages = {161 - 3},
Address = {USA},
Year = {2003},
Month = {January},
ISBN = {1557527504},
Keywords = {image segmentation;optical sensors;optical
tomography;},
Abstract = {We describe a sensor system based on 3D 'reference
structures' which implements a mapping from a 3D source
volume on to a 2D sensor plane. We consider examples of a
few reference structures and how they spatially segment a 3D
source volume and present some results.},
Key = {8126136}
}
@article{fds331445,
Author = {Brady, DJ and Feller, SD and Kammeyer, D and Cull, E and Fernandes, L and Stack, RA and Brady, R},
Title = {Information flow in streaming 3D video},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {10298},
Publisher = {SPIE},
Year = {2001},
Month = {February},
url = {http://dx.doi.org/10.1117/12.419785},
Abstract = {We describe streaming 3D video on the Argus sensor space.
Argus is a Beowulf-style distributed computer with 64
processors and 64 video camera/capture pairs. Argus is a
test-bed for comparing sensor space modeling and
reconstruction algorithms. We describe the implementation of
tomographic and stereo triangulation algorithms on this
space and consider mappings from the sensor space to
associated display spaces.},
Doi = {10.1117/12.419785},
Key = {fds331445}
}
@article{fds323555,
Author = {Gallicchio, J and Cull, E and Kraut, S and Brady,
DJ},
Title = {Spatio-spectral triangulation using a rotational shear
interferometer},
Journal = {Optics Infobase Conference Papers},
Volume = {66},
Pages = {207-209},
Publisher = {OPTICAL SOC AMERICA},
Editor = {Mait, JN and VanderGracht, J},
Year = {2001},
Month = {January},
ISBN = {9781557528209},
Abstract = {We use a rotational shearing interferometer to determine the
angular location and wavelength of sparse point sources by
capturing 2 interference patterns on a CCD array. We
demonstrate this using a portable RSI with embedded
processing.},
Key = {fds323555}
}
@article{fds323556,
Author = {Brady, DJ and Potuluri, P},
Title = {Spatial tomography and coherence microscopy},
Journal = {Optics Infobase Conference Papers},
Volume = {66},
Pages = {147-149},
Publisher = {OPTICAL SOC AMERICA},
Editor = {Mait, JN and VanderGracht, J},
Year = {2001},
Month = {January},
ISBN = {9781557528209},
Abstract = {We describe a methodology for integrated computational
imaging system design based on source specification,
cross-spectral transformations and tomography. We consider
design examples based on local and nonlocal measures of
incoherent primary sources.},
Key = {fds323556}
}
@article{fds365934,
Author = {Marks, DL and Stack, RA and Brady, DJ},
Title = {Three-dimensional coherence imaging in the Fresnel
domain},
Journal = {Optics Infobase Conference Papers},
Pages = {61-71},
Year = {2001},
Month = {January},
ISBN = {9781557528209},
Abstract = {We show that three-dimensional incoherent primary sources
can be reconstructed from finite-aperture Fresnel-zone
mutual intensity measurements by means of coordinate and
Fourier transformation. The spatial bandpass and impulse
response for three-dimensional imaging that result from use
of this approach are derived. The transverse and
longitudinal resolutions are evaluated as functions of
aperture size and source distance. The longitudinal
resolution of three-dimensional coherence imaging falls
inversely with the square of the source distance in both the
Fresnel and Fraunhofer zones. We experimentally measure the
three-dimensional point-spread function by using a
rotational shear interferometer.},
Key = {fds365934}
}
@article{fds365935,
Author = {Morrison, RL and Stack, RA and Brady, DJ},
Title = {Insights from the development of two generations of
networked sensor and processor systems},
Journal = {Optics Infobase Conference Papers},
Pages = {190-192},
Year = {2001},
Month = {January},
ISBN = {9781557528209},
Abstract = {A wirelessly networked array of integrated sensor and
processing modules has demonstrated video-rate tomographic
reconstruction previously shown on a video enabled
supercomputer cluster. We discuss issues regarding design
and development of these first- and second-generation
distributed sensing and processing platforms.},
Key = {fds365935}
}
@article{6615723,
Author = {Tumbar, R and Brady, DJ},
Title = {Sensor plane processing for multiplex imaging},
Journal = {2000 Southwest Symposium on Mixed Signal Design, Ssmsd
2000},
Pages = {1-6},
Publisher = {IEEE},
Address = {San Diego, CA, USA},
Year = {2000},
Month = {January},
ISBN = {0780359755},
url = {http://dx.doi.org/10.1109/SSMSD.2000.836433},
Keywords = {image processing;image processing equipment;image
sensors;},
Abstract = {Digital imaging systems are fundamentally different from
analog ones because they differentiate the measurement space
and the reconstruction space. Multiplex systems use this
separation to optimize source reconstruction. We consider
the requirements imposed on sensor plane processors by
multiplex imaging systems. We consider system flexibility,
analog/digital split, A/D dynamic range, bandwidth, and
sensitivity.},
Doi = {10.1109/SSMSD.2000.836433},
Key = {6615723}
}
@article{6806097,
Author = {Balberg, M and Hristova, R and Brady, DJ and Beebe, DJ and Raskin,
L},
Title = {Optical detection of molecular beacons in microfluidic
devices},
Journal = {1st Annual International Ieee Embs Special Topic Conference
on Microtechnologies in Medicine and Biology
Proceedings},
Pages = {425-428},
Publisher = {IEEE},
Address = {Lyon, France},
Year = {2000},
Month = {January},
ISBN = {0780366034},
url = {http://dx.doi.org/10.1109/MMB.2000.893820},
Keywords = {biological techniques;fibre optic sensors;fluidic
devices;fluorescence;microfluidics;microorganisms;molecular
biophysics;spectrophotometry;},
Abstract = {Hybridization and detection of E. coli ribosomal RNA with
molecular beacons labeled with a fluorescent dye Is achieved
in a microfluidic device. The device consists of a four
ports mixing chamber, where the probes and the target
molecules mix by diffusion. The weak fluorescent signal is
detected by two large core optical fibers that are placed on
both sides of the channel and collect the light emitted in
both directions. The fibers are coupled to a
spectrophotometer. The detection limit for the system is 0.2
ftnol.},
Doi = {10.1109/MMB.2000.893820},
Key = {6806097}
}
@article{fds330755,
Author = {Sirlceci, B and Brady, D and Burman, J},
Title = {Restricted total least squares solutions for hyperspectral
imagery},
Journal = {2015 Ieee International Conference on Acoustics, Speech, and
Signal Processing (Icassp)},
Volume = {1},
Pages = {624-627},
Publisher = {IEEE},
Year = {2000},
Month = {January},
ISBN = {0780362934},
url = {http://dx.doi.org/10.1109/ICASSP.2000.862059},
Abstract = {Hyperspectral image processing is a pixel-by-pixel approach
to the detection and localization of features by spectral
analysis techniques. Usually, partial knowledge about the
feature, noise, and clutter spectra are provided, and the
problem is to 'unmix' each pixel, or to estimate the
relative concentrations of the reference spectra on a per
pixel basis. A popular method of linear spectral unmixing
for hyperspectral imagery is linear least squares. Linear
least square approaches are appropriate when observational
errors predominate and are inappropriate when significant
modeling errors are present. The least square approach has
some disadvantages, especially in cases with few, poorly
known references or significant reference variation
throughout an image. approach is presented and evaluated on
experimental data. Although proposed RTLS require more
calculations than linear least squares, its relative error
performance is much better. In this article, Restricted
Total Least Squares(RTLS).},
Doi = {10.1109/ICASSP.2000.862059},
Key = {fds330755}
}
@article{fds330754,
Author = {Sung, S and Brady, D},
Title = {Spectral spatial equalization for OFDM in time-varying
frequency-selective multipath channels},
Journal = {Proceedings of the Ieee Sensor Array and Multichannel Signal
Processing Workshop},
Volume = {2000-January},
Pages = {434-438},
Publisher = {IEEE},
Year = {2000},
Month = {January},
ISBN = {0780363396},
url = {http://dx.doi.org/10.1109/SAM.2000.878046},
Abstract = {Orthogonal frequency division multiplex (OFDM) transmission
over a time-variant frequency-selective multipath fading
channel suffers from significant attenuation on faded
frequency regions as well as inter-channel interference
(ICI) due to the loss of subchannel orthogonality. To
mitigate signal fading and ICI, we introduce a
frequency-space domain equalization (FSDE) using an antenna
array. Unlike conventional combining diversity or selection
diversity, this scheme differs in that it attempts to
prevent the occurrence of the frequency-selective fading and
ICI rather than compensates for them. A FSDE on the received
OFDM signal is performed by space-time Fourier transform
(STFT) and frequency-domain equalization (FDE). While a
time-domain Fourier transform in STFT demodulates OFDM
signals, a space-domain Fourier transform attenuates the
OFDM signals arriving at the antenna array through unwanted
paths. This approach includes the blind estimation of the
direction-of-arrival (DOA) for the multiple paths by
employing the cyclostationarity of the OFDM signal. A FDE is
applied to the output of the STFT to compensate for the
effect of the remaining ICI. The effectiveness of FSDE is
examined in terms of the resulting frequency-selective
fading, ICI and SINR gain.},
Doi = {10.1109/SAM.2000.878046},
Key = {fds330754}
}
@article{7055381,
Author = {Morrison, RL and Brady, DJ},
Title = {Diffractive and Micro-Optics for Multiplex
Imaging},
Journal = {Optics Infobase Conference Papers},
Pages = {284-285},
Address = {Quebec City, Que., Canada},
Year = {2000},
Month = {January},
ISBN = {9781557528209},
Keywords = {diffractive optical elements;light scattering;micro-optics;optical
design techniques;optical dispersion;optical
images;},
Abstract = {Multiplex systems require complex field encoding but are not
particularly sensitive to discontinuity or chromatic
dispersion. Diffractive and micro-optics provide a complex
design space but have scattering and dispersion problems.
This is a match made in heaven.},
Key = {7055381}
}
@article{fds365936,
Author = {Barbastathis, G and Balberg, M and Brady, DJ},
Title = {Confocal microscopy without pinhole},
Journal = {Optics Infobase Conference Papers},
Year = {1999},
Month = {January},
ISBN = {9781557528209},
Abstract = {Confocal microscopes achieve depth resolution by use of a
pinhole. On-axis, in-focus point-source objects are imaged
exactly inside the pinhole, and give maximal intensity.
Out-of-focus objects, even on-axis, produce extended
(blurred) images, and are filtered out by the limited
aperture of the pinhole. Theoretically, the depth resolution
is optimal when an infinitessimally small pinhole is used
[1]. However, such an ad hoc filter does not match perfectly
the impulse response of any realistic optical system. In
practice, the minimum pinhole size, and, hence, the depth
resolution limit, are determined by light efficiency (i.e.,
the required dynamic range of the measurement) and the
broadening of the focal spot by lens aberrations [2]. Using
a complex filter, implemented as a thin diftactive element,
instead of a pinhole infront of the detector, has been
proposed as a means for achieving super-resolution [3,
4].},
Key = {fds365936}
}
@article{fds365937,
Author = {Marks, DL and Stack, R and Brady, DJ},
Title = {Coherence-based Hybrid Optical/Computational Approaches to
Three-dimensional Incoherent Imaging},
Journal = {Optics Infobase Conference Papers},
Pages = {167-169},
Year = {1999},
Month = {January},
ISBN = {9781557528209},
Key = {fds365937}
}
@article{fds365938,
Author = {Barbastathis, G and Balberg, M and Brady, DJ},
Title = {Superresolved imaging architectures with volume
holograms},
Journal = {Optics Infobase Conference Papers},
Pages = {175-177},
Year = {1999},
Month = {January},
ISBN = {9781557528209},
Key = {fds365938}
}
@article{fds330757,
Author = {Preisig, J and Brady, D},
Title = {Adaptive equalization for underwater wireless
communications},
Journal = {Icassp, Ieee International Conference on Acoustics, Speech
and Signal Processing Proceedings},
Volume = {2},
Pages = {1077-1080},
Year = {1996},
Month = {January},
Abstract = {Wireless acoustic communications through the underwater
channel presents many challenges. On one hand, the channel
is often characterized by an extended time-varying multipath
structure spanning a hundred or more symbols, limited
channel coherence times, and high signal loss due to
absorption resulting in limited available bandwidth. On the
other hand, many applications for which wireless
communications through this channel would be useful impose
severe limits on the available power and the cost of the
required hardware. These constraints limit not only the
available transmit power but also the available
computational power. Thus, modulation and demodulation
approaches must be developed which can cope with the often
difficult channel conditions but which also require only
limited resources. This paper reviews the salient features
of the underwater acoustic propagation environment, presents
several techniques which have been developed to provide
reliable communications in this environment, and highlights
some of the remaining challenges.},
Key = {fds330757}
}
@article{fds330759,
Author = {Johnson, M and Brady, D and Grund, M},
Title = {Reducing the computational requirements of adaptive
equalization in underwater acoustic communications},
Journal = {Oceans Conference Record (Ieee)},
Volume = {3},
Pages = {1405-1410},
Year = {1995},
Month = {December},
Abstract = {A key component in coherent underwater acoustic
communication systems is an adaptive equalizer capable of
tracking changes in the acoustic environment. The
computation requirements of this equalizer can be very high,
requiring substantial computation hardware and high power
consumption. Several techniques have been devised for
reducing the computational load of the equalizer by
exploiting structure in the acoustic environment. In
essence, these methods trade equalizer decoding performance
for computational efficiency by reducing the number of
equalizer parameters, the complexity of the update
algorithm, or the rate of parameter updating. In this paper,
a generalized equalizer model is developed combining several
such complexity reduction techniques. From this viewpoint,
the potential and limitations of each technique are
discussed. Results are presented showing that computation
savings in excess of an order of magnitude are
possible.},
Key = {fds330759}
}
@article{fds330758,
Author = {Kocic, M and Brady, D and Stojanovic, M},
Title = {Sparse equalization for real-time digital underwater
acoustic communications},
Journal = {Oceans Conference Record (Ieee)},
Volume = {3},
Pages = {1417-1422},
Year = {1995},
Month = {December},
Abstract = {Due to the very long reverberation time of many ocean
channels, the size of the adaptive filters required for
conventional equalization becomes large, rendering the
computational complexity of the adaptive receiver
unacceptable for many cases of practical interest. To
overcome this problem we exploit the natural sparseness of
the reverberation pattern. By focusing only on those
intervals which contain a significant portion of the signal
energy, the sparse equalization method provides data
detection using a minimum complexity adaptive receiver
subject to an upper bound on the signal estimation error.
Experimental results demonstrate an order of magnitude
reduction in computational complexity with a negligible loss
in performance.},
Key = {fds330758}
}
@article{fds330762,
Author = {Zhang, X and Brady, D},
Title = {Asymptotic coding gains in multiuser systems},
Journal = {Ieee Vehicular Technology Conference},
Volume = {2},
Pages = {619-623},
Year = {1995},
Month = {January},
Abstract = {In this work the asymptotic multiuser coding gain (AMCG) as
well as asymptotic multiuser efficiency (AME) are found for
K coded asynchronous users and a variety of multiuser
detectors, including optimum (MLS), multistage, decorrelated
and conventional detectors. Since the direct sequence can be
viewed as a special kind of block repetition codes, it gives
zero (dB) coding gain in power-limited application. It is
shown that some block encoding schemes with (n, k), k > 1
can provide direct-sequence spread-spectrum modulation and
give positive coding gain. These systems combined with the
narrow-band signature waveforms are shown to outperform
their conventional approachs with the same bandwidth
expansion constraint.},
Key = {fds330762}
}
@article{fds330769,
Author = {Zhang, X and Brady, D},
Title = {Narrowband waveform design for near-far resistant
asynchronous CDMA communications},
Journal = {Ieee Milcom},
Volume = {2},
Pages = {583-587},
Year = {1994},
Month = {December},
Abstract = {A technique to design narrowband signature waveforms for
asynchronous code-division multiple-access (CDMA) systems is
proposed. These waveforms are specially tailored for a class
of near-far resistant multiuser detectors. They are strictly
time-limited, satisfy a root mean square (RMS) bandwidth
constraint, and provide a prescribed worst-case near-far
resistance. The optimization criterion is either the maximum
worst-case pairwise near-far resistance (NFR), or the
maximum worst-case pairwise asymptotic multiuser efficiency
(AME) of L-shot decorrelating detector over all relative
delays of users. These signal set are shown to be immune to
synchronization errors as well by using slope constraints of
partial cross-correlations over relative delays. Complex
signature waveforms are also considered. It is shown that
'chipless' waveforms provide a substantial increase in
performance in near-far situations over their chip-based
counterparts using the same transmission
bandwidth.},
Key = {fds330769}
}
@article{fds330770,
Author = {Brady, D and Merakos, LF},
Title = {Throughput performance of multiuser detection in unslotted
contention channels},
Journal = {Proceedings Ieee Infocom},
Volume = {2},
Pages = {610-617},
Year = {1994},
Month = {December},
Abstract = {The throughput of a centralized packet receiver capable of
demodulating all overlapping unit-length packets provided
that T-length packet headers do not overlap but K packets
overlap at any one time, is analyzed. Violating one of the
stated conditions suggests that the remainder of the busy
period is unresolvable. Assuming that the aggregate packet
arrival process is Poisson, the throughput is analyzed as a
function of the total offered load, the maximum number of
resolvable overlapping packets, and the fractional header
duration. The throughput of the analyzed functions are
given. Numerical results illustrate the improvement in
throughput due to multiuser detection which suggest a
technique for finding the minimum complexity multiuser
receiver as a function of other system parameters.},
Key = {fds330770}
}
@article{fds330768,
Author = {Zvonar, Z and Brady, D},
Title = {Adaptive multiuser receivers with diversity reception for
nonselective Rayleigh fading asynchronous CDMA
channels},
Journal = {Ieee Milcom},
Volume = {3},
Pages = {982-986},
Year = {1994},
Month = {December},
Abstract = {We investigate the performance of low-complexity
decor-relating multiuser receivers with diversity reception
in frequency-nonselective Rayleigh fading asynchronous CDMA
channels. The impact of fading dynamics on the
differentially coherent receivers with equal-gain combining
is quantified. We also analyze an adaptive coherent
multiuser receiver utilizing decision-directed carrier
recovery and maximal ratio combining, and bound its error
probability showing the impact of imperfect channel
estimates and multiple-access interference. Both multiuser
receivers have superior performance compared to their
conventional counterparts. The comparison of two receiver
structures indicates that the coherent decorrelating
detector with diversity reception is preferable in
nonselective fading CDMA channels with memory.},
Key = {fds330768}
}
@article{fds330766,
Author = {Kocic, M and Brady, D},
Title = {Complexity-constrained LS estimation for sparse
systems},
Journal = {Ieee International Symposium on Information Theory
Proceedings},
Year = {1994},
Month = {December},
Abstract = {The Sparse RLS (SRLS) algorithm, suitable for large-order
sparse channels, chooses to update a subset of taps which
will minimize the computational complexity of the algorithm
given the constraint of maximum allowable increases in Mean
Squared Error (MSE). The ability to predict the increase in
MSE due to decision to neglect some of the taps is essential
for its implementation. To illustrate the principles behind
the algorithm, an example is presented by way of an
experimental transmission of known data through an unknown
shallow-water acoustic channel.},
Key = {fds330766}
}
@article{fds330767,
Author = {Kocic, M and Brady, D and Merriam, S},
Title = {Reduced-complexity RLS estimation for shallow-water
channels},
Journal = {Ieee Sympsium on Autonomous Underwater Vehicle
Technology},
Pages = {165-170},
Year = {1994},
Month = {December},
Abstract = {An adjustable complexity, recursive least squares (RLS)
estimation algorithm is presented, which is suitable for
adaptive equalization and source localization in
shallow-water acoustic channels. The algorithm adjusts its
computational complexity, measured in FLOPS per update, in a
decreasing fashion with the relative signal strength, by
ignoring 'insignificant' dimensions of the channel. The
algorithm reverts to the well-known fast RLS algorithms when
the signal quality is weak, and may be combined with reduced
period updating techniques. Examples illustrate
computational savings in excess of one order of magnitude,
permitting a tripling of the maximum data rate through these
complexity - limited communication channels.},
Key = {fds330767}
}
@article{fds330764,
Author = {Kocic, M and Brady, D},
Title = {Complexity-constrained LS estimation for sparse
systems},
Journal = {Ieee International Symposium on Information Theory
Proceedings},
Pages = {116},
Publisher = {IEEE},
Year = {1994},
Month = {December},
ISBN = {0780320158},
url = {http://dx.doi.org/10.1109/ISIT.1994.394872},
Abstract = {In an increasing number of applications the complexity of
so-called fast RLS algorithms is prohibitive for real-time
RLS estimation. One notable example is the adaptive
equalization problem for intersymbol interference channels,
where the number of equalizer taps grows linearly with the
data rate. Due to the substantial memory in some ISI
channels (for example the shallow-water acoustic telemetry
channel) the uncoded data rate of real-time telemetry is
limited not by the channel distortion or background noise,
but by the complexity of the tap update algorithms. © 1994
IEEE.},
Doi = {10.1109/ISIT.1994.394872},
Key = {fds330764}
}
@article{fds330765,
Author = {Brady, D and Merakos, LF},
Title = {Throughput performance of multiuser detection in unslotted
contention channels},
Journal = {Ieee International Symposium on Information Theory
Proceedings},
Year = {1994},
Month = {December},
Abstract = {In this work we analyze the throughput of a centralized
packet receiver which utilizes multiuser detection in an
unslotted contention channel. The receiver is capable of
demodulating all overlapping, unit-length packets, provided
that the T-length packet headers do not overlap, and at most
K packets overlap at any one time. If one of these
conditions is violated, the remainder of the busy period is
assumed to be unresolvable. Assuming that the aggregate
packet arrival process is Poisson, we analyze the throughput
as a function of the total offered load (λ), the maximum
number of resolvable overlapping packets (K), and the
fractional header duration (T). We derive an iterative
expression for the throughput for K = 2 or 3, generalizable
to larger K, which permits solution of the throughput to
arbitrary accuracy. A closed form solution is given for the
case K = 2 and T = 0.5. We provide bounds on the throughput
for arbitrary K, λ, and T, which are more convenient than
the exact approach for T > 0 or large K. Numerical results
illustrate the improvement in throughput due to multiuser
detection, and suggest a technique for finding the minimum
complexity multiuser receiver (minimum K) as a function of
other system parameters.},
Key = {fds330765}
}
@article{fds342408,
Author = {Gray, SD and Preisig, JC and Brady, D},
Title = {Adaptive multiuser detection in dispersive channels with
array observations},
Journal = {Conference Record Asilomar Conference on Signals, Systems
and Computers},
Volume = {2},
Pages = {801-805},
Year = {1994},
Month = {January},
ISBN = {0818664053},
url = {http://dx.doi.org/10.1109/ACSSC.1994.471572},
Abstract = {We present a multiuser receiver which is capable of
operating in time-variant channels with severe multipath.
For each active user, the receiver consists of a
multi-input, single-output filter followed by a single-user
adaptive equalizer. The array processing filter is chosen to
maximize an averaged performance metric which measures
reduction in the interference from multiple asynchronous
cochannel users and the reduction in intersym-bol
interference caused by lime spreading of the transmitted
signal. The single-user adaptive equalizer that follows the
array processing filter eliminates the remaining intersymbol
interference prior to hard symbol decisions. Receiver
performance is demonstrated using data obtained from two
acoustic channels where two cochannel users are transmitting
in shallow-water at 18 and 30 nautical miles from the
receiver array.},
Doi = {10.1109/ACSSC.1994.471572},
Key = {fds342408}
}
@article{fds330773,
Author = {Gray, SD and Brady, D},
Title = {Asymptotic multiuser efficiency of two-stage detection in
mismatched AWGN channels},
Journal = {Proceedings Ieee Military Communications
Conference},
Volume = {3},
Pages = {758-762},
Year = {1993},
Month = {December},
ISBN = {0780309537},
Abstract = {In this paper we investigate the loss of near-far resistance
for two multiuser detectors due to imperfect channel
estimation in the additive white Gaussian noise multiple
access channel. The symbol error rates and the Asymptotic
Multiuser Efficiencies (AMEs) of the two-stage hard-limiting
detector are determined for imperfect channel knowledge in
the two-user asynchronous channel. The degradation of the
AME due to channel mismatch is described for a variety of
mismatch conditions, including errors in estimation of
timing and complex amplitude. It is shown that when perfect
knowledge of the channel does not exist, the two-stage
detector become near-far limited. Also presented is a
comparison of the exponentially complex maximum likelihood
sequence detector and the hard-decision two-stage detector
with imperfect knowledge of the channel.},
Key = {fds330773}
}
@article{fds330774,
Author = {Zvonar, Z and Brady, D and Catipovic, J},
Title = {Adaptive equalization techniques for interference
suppression in shallow water acoustic telemetry
channels},
Journal = {Conference Record Asilomar Conference on Signals, Systems
and Computers},
Volume = {2},
Pages = {1554-1558},
Year = {1993},
Month = {December},
ISBN = {0818641207},
Abstract = {Despite the severe propagation conditions in shallow water
acoustic telemetry channels, coherent high-speed data
transmission may be established using adaptive receivers
based on a decision feedback equalizer (DFE) structure. The
performance of a DFE in shallow water acoustic networks is
affected by substantial cochannel interference from acoustic
modems, in addition to extended, time-varying ISI and large
Doppler fluctuations. In this paper we address the
interference suppression ability of a DFE by evaluating a
channel-specific structure for reliable interference
suppression and dynamic channel tracking. The DFE
performance is compared to adaptive multiuser receiver which
jointly performs adaptive equalization and multiple-access
interference cancellation.},
Key = {fds330774}
}
@article{fds342515,
Author = {Brady, D},
Title = {Volume holographic data storage in photo-organic
media},
Journal = {Conference Digest Joint International Symposium on Optical
Memory and Optical Data Storage, Omods 1993},
Pages = {112-113},
Year = {1993},
Month = {January},
ISBN = {0780312864},
url = {http://dx.doi.org/10.1109/OMODS.1993.696746},
Doi = {10.1109/OMODS.1993.696746},
Key = {fds342515}
}
@article{fds330775,
Author = {Brady, D},
Title = {Asymptotic multiuser efficiency for 2-stage detectors in
AWGN channels},
Journal = {Proceedings of the 1993 Ieee International Symposium on
Information Theory},
Pages = {50},
Year = {1993},
Month = {January},
ISBN = {0780308786},
Abstract = {In the AWGN multiple-access channel with binary phase-shift
keying modulation, the kth user error probability for a
given demodulator vanishes exponentially with the noise
level as -ηk SNRk/2, where ηk is the asymptotic multiuser
efficiency (AME), and SNRk is the received
signal-to-background-noise ratio. Thus, the asymptotic
multiuser efficiency is an attenuation of the error rate
exponent for isolated transmission and maximum a posteriori
demodulation, and provides a simple yet precise means of
comparing multiuser receivers for sufficiently low noise
levels. To date, this parameter is only known for the
following receivers in the 2-user, asynchronous AWGN
channel: the maximum likelihood sequence detector, the
decorrelating detector, the linear MMSE detector, and the
conventional detector. In this talk the asymptotic multiuser
efficiencies for a class of detectors for the 2-user,
asynchronous AWGN channel: will be presented. This class may
be loosely described as receivers which estimate and
subtract multiple-access interference (MAI) by using
tentative data decisions, and includes the two-stage
detectors with both conventional or decorrelated tentative
decisions. The asymptotic multiuser efficiencies for this
class of detectors clearly indicate regions for which a
given user should avoid updating tentative decisions and
suggest combinations of the above receivers to improve
single-user performance. This technique applies to the AME
of soft tentative decision strategies as well, and we
demonstrate that the near-far resistance of two-stage
detectors may be markedly improved using soft decision
nonlinearities. Below we present an outline of the approach
for conventional tentative decisions.},
Key = {fds330775}
}
@article{fds330776,
Author = {Zvonar, Z and Brady, D},
Title = {Comparison of differentially coherent and coherent multiuser
detection with imperfect phase estimates in a Rayleigh
fading channel},
Journal = {Proceedings of the 1993 Ieee International Symposium on
Information Theory},
Pages = {48},
Year = {1993},
Month = {January},
ISBN = {0780308786},
Abstract = {Multiuser detectors have superior performance over their
single-user counterparts in a multiple-access channel,
assuming perfect knowledge of system parameters. In this
paper we extend the analysis of multiuser detectors in
fading channels by incorporating the effects of imperfect
parameter estimates on symbol error probability. This type
of analysis should be useful in designing multiuser
receivers, showing the error rate sensitivity to channel
parameter mismatch.},
Key = {fds330776}
}
@article{fds366170,
Author = {Hill, KB and Brady, DJ},
Title = {Integrated Optical Pulse Shaping},
Journal = {Optics Infobase Conference Papers},
Pages = {246-249},
Year = {1993},
Month = {January},
ISBN = {9781557528209},
Key = {fds366170}
}
@article{fds366171,
Author = {Papen, GC and Murphy, GM and Brady, DJ and Howe, AT and Dallesasse, JM and Dejule, RY and Holmgren, DJ},
Title = {Multiple Wavelength Operation of a Diode Array Coupled to an
External Cavity},
Journal = {Optics Infobase Conference Papers},
Year = {1993},
Month = {January},
ISBN = {1557521891},
Key = {fds366171}
}
@article{fds343779,
Author = {Zvonar, Z and Brady, D},
Title = {On multiuser detection in asynchronous CDMA flat Rayleigh
fading channels},
Journal = {Ieee International Symposium on Personal, Indoor and Mobile
Radio Communications, Pimrc},
Pages = {123-127},
Year = {1992},
Month = {January},
ISBN = {0780308417},
url = {http://dx.doi.org/10.1109/PIMRC.1992.279951},
Abstract = {In this paper the performance analysis of lowcomplexity
decorrelating detectors will be presented for both coherent
and differentially coherent transmission over the
multiple-access, frequencynonselective Rayleigh fading
channel. While it is known that correlation-type receivers
are near-far limited in the case when a single fading path
dominates, it is shown that the aforementioned multiuser
detectors eliminate the bit error rate floor, alleviate the
near-far problem, and rival optimum demodulation for
isolated transmission. The results herein apply to wideband
and narrowband CDMA systems.},
Doi = {10.1109/PIMRC.1992.279951},
Key = {fds343779}
}
@article{fds342841,
Author = {Brady, D and Catipovic, J},
Title = {An adaptive, soft-decision multiuser receiver for underwater
acoustical channels},
Journal = {Conference Record Asilomar Conference on Signals, Systems
and Computers},
Pages = {1137-1141},
Year = {1992},
Month = {January},
ISBN = {0818631600},
url = {http://dx.doi.org/10.1109/ACSSC.1992.269121},
Abstract = {An underwater acoustic local area network (ALAN) is being
deployed which permits two-way data telemetry between many
high-rate, ocean-bottom sensors and a central,
surface-deployed receiver in the 10- 40kHz vertical
acoustical channel [1]. The oceanbottom nodes initiate the
transmission process by requesting data channel time slots
through a common narrowband request channel. Request packets
overlap in time and frequency in this scenario, and the
throughput and average transmission delay rely heavily on
the successful resolution of the request channel collisions.
This paper describes the design and performance of a request
channel receiver capable of resolving collisions between
several asynchronous and cochannel packets. The receiver
algorithm differs from: standard capture schemes (by
demodulating the data from both strong and weak
transmitters), conventional spread-spectrum receivers (by
overcoming the near-far problem), and existing
multiple-access demodulation techniques (by adapting to the
number of interfering signals, and the unknown phase,
Doppler, amplitude and timing of each signal in the
collision). The receiver demodulates the collided packets by
decision-directed techniques, it differs from known
decision-directed multiple-access receivers [2] [3] [4]
through a novel method of estimating the interference for
each user which minimizes error propagation due to
inaccurate tentative decisions [5] [6]. An in-water
experiment illustrates that this technique is extremely
desirable for collision resolution in underwater acoustic
local area networks, and also for underwater autonomous
vehicles with both sidescan sonar as well as acoustic
telemetry links.},
Doi = {10.1109/ACSSC.1992.269121},
Key = {fds342841}
}
@article{fds343778,
Author = {Zvonar, Z and Brady, D},
Title = {Coherent and differentially coherent multiuser detectors for
asynchronous CDMA frequency-selective channels},
Journal = {Proceedings Ieee Military Communications Conference
Milcom},
Volume = {1992-October},
Pages = {442-446},
Year = {1992},
Month = {January},
ISBN = {078030585X},
url = {http://dx.doi.org/10.1109/MILCOM.1992.244040},
Abstract = {The authors consider an asynchronous CDMA (code-division
multiple-access) frequency-selective Rayleigh fading channel
in which a central receiver has knowledge of the signature
waveforms of all users. Low-complexity coherent and
differentially coherent multiuser detectors are analyzed for
this scenario. The receivers consist of a bank of matched
filters followed by a multipath decorrelating detector,
appropriate multipath diversity combining, and demodulation.
The performance of the derived detectors is expressed by the
single-user error rate. The conventional single-user RAKE
receiver suffers from near-far effects in the multiuser
scenario, due to the fading nature of the channel. This
results in an error probability floor for high
signal-to-noise ratios and limits the multiple-access
capability of the system. In contrast, both multiuser
detectors alleviate the near-far problem, providing
significant performance improvement in the CDMA
frequency-selective fading channel.},
Doi = {10.1109/MILCOM.1992.244040},
Key = {fds343778}
}
@article{fds365218,
Author = {Brady, DJ and Papen, GC and Hill, KB},
Title = {Holographic Photonic Band Gaps},
Journal = {Optics Infobase Conference Papers},
Year = {1991},
Month = {January},
ISBN = {1557521913},
Key = {fds365218}
}
@article{91080258299,
Author = {Brady, D and Verdu, S},
Title = {A semi-classical analysis of optical code division multiple
access},
Journal = {Conference Digest. Leos Summer Topical on Optical Multiple
Access Networks},
Pages = {43-44},
Address = {Monterey, CA, USA},
Year = {1990},
Month = {December},
url = {http://dx.doi.org/10.1109/OMAN.1990.205430},
Keywords = {Multiplexing;Codes, Symbolic;},
Abstract = {The exact error rate has been derived for the noncoherent,
optical matched-filter CDMA receiver, which decides for the
data of a single user by comparing a photoelectron count to
a threshold. The results differ from those of previous work
in that they adhere fully to the semiclassical model of
light and do not depend on limit theorems for large user
groups or strong received optical fields. The analysis is
valid for arbitrary quantum efficiencies, binary signature
sequences, random gain distributions, and dark currents, and
it is broad in application. Single-user demodulation based
on a conditionally compound-Poisson observation has been
considered, focusing on the special case of prime codes,
equal energies, and utility-gain photodetectors in order to
compare the optimal threshold and minimum error rate to
those obtained using the approximations discussed. It has
been found that the approximation of perfect
optical-to-electrical conversion yields poor estimates of
the error rate and optimal threshold at moderate incident
optical intensities and dark currents. Further, the combined
approximation of perfect optical-to-electrical conversion
and Gaussian-distributed MAI yields an underestimate of the
optimal threshold and an error rate that is neither an upper
nor a lower bound. It has also been shown that when prime
sequences are employed, the chip-synchronous approximation
leads to an overestimate of the error rate.},
Key = {91080258299}
}
@article{fds330781,
Author = {Brady, D and Verdu, S},
Title = {Probability of error of an optical DPSK detector under
Brownian laser phase noise},
Volume = {25 n 13},
Pages = {198},
Year = {1988},
Month = {December},
Abstract = {Summary form only given, as follows. The authors analyze an
optical, direct-detection DPSK receiver whose error
probability is quantum-limited as the transmitting laser
linewidth vanishes. The receiver design is based on a binary
equiprobable hypothesis test with doubly stochastic point
process observations, the conditional random rates of which
depend on the transmitting laser phase noise, which is
modeled as a Brownian motion. The receiver structure
consists of a simple, delay-and-sum optical preprocessor
followed by a photodetector. Upper and lower bounds on the
receiver bit error rate are derived by developing bounds on
the conditional rates of the point process, and it is shown
that the error probability bounds converge to the true value
as the transmitting laser linewidth decreases. Bounds on the
power penalty are derived for parameters corresponding to
existing semiconductor injection lasers, and are seen to be
less than the limiting power penalty for the balanced DPSK
receiver.},
Key = {fds330781}
}
%% Papers Published
@article{fds366689,
Author = {Zhang, Z and Zhang, B and Yuan, X and Zheng, S and Su, X and Suo, J and Brady,
DJ and Dai, Q},
Title = {From compressive sampling to compressive tasking: retrieving
semantics in compressed domain with low bandwidth},
Journal = {Photonix},
Volume = {3},
Number = {1},
Year = {2022},
Month = {December},
url = {http://dx.doi.org/10.1186/s43074-022-00065-1},
Abstract = {High-throughput imaging is highly desirable in intelligent
analysis of computer vision tasks. In conventional design,
throughput is limited by the separation between physical
image capture and digital post processing. Computational
imaging increases throughput by mixing analog and digital
processing through the image capture pipeline. Yet, recent
advances of computational imaging focus on the
“compressive sampling”, this precludes the wide
applications in practical tasks. This paper presents a
systematic analysis of the next step for computational
imaging built on snapshot compressive imaging (SCI) and
semantic computer vision (SCV) tasks, which have
independently emerged over the past decade as basic
computational imaging platforms. SCI is a physical layer
process that maximizes information capacity per sample while
minimizing system size, power and cost. SCV is an
abstraction layer process that analyzes image data as
objects and features, rather than simple pixel maps. In
current practice, SCI and SCV are independent and
sequential. This concatenated pipeline results in the
following problems: i) a large amount of resources are spent
on task-irrelevant computation and transmission, ii) the
sampling and design efficiency of SCI is attenuated, and
iii) the final performance of SCV is limited by the
reconstruction errors of SCI. Bearing these concerns in
mind, this paper takes one step further aiming to bridge the
gap between SCI and SCV to take full advantage of both
approaches. After reviewing the current status of SCI, we
propose a novel joint framework by conducting SCV on raw
measurements captured by SCI to select the region of
interest, and then perform reconstruction on these regions
to speed up processing time. We use our recently built SCI
prototype to verify the framework. Preliminary results are
presented and the prospects for a joint SCI and SCV regime
are discussed. By conducting computer vision tasks in the
compressed domain, we envision that a new era of snapshot
compressive imaging with limited end-to-end bandwidth is
coming.},
Doi = {10.1186/s43074-022-00065-1},
Key = {fds366689}
}
@article{fds369384,
Author = {Huang, Q and Hu, M and Brady, DJ},
Title = {Array Camera Image Fusion using Physics-Aware
Transformers},
Journal = {Journal of Imaging Science and Technology},
Volume = {66},
Number = {6},
Year = {2022},
Month = {November},
url = {http://dx.doi.org/10.2352/J.ImagingSci.Technol.2022.66.6.060401},
Abstract = {We demonstrate a physics-aware transformer for feature-based
data fusion from cameras with diverse resolution, color
spaces, focal planes, focal lengths, and exposure. We also
demonstrate a scalable solution for synthetic training data
generation for the transformer using open-source computer
graphics software. We demonstrate image synthesis on arrays
with diverse spectral responses, instantaneous field of view
and frame rate.},
Doi = {10.2352/J.ImagingSci.Technol.2022.66.6.060401},
Key = {fds369384}
}
@article{fds365215,
Author = {Yuan, X and Brady, DJ and Suo, J and Arguello, H and Rodrigues, M and Katsaggelos, AK},
Title = {Editorial: Introduction to the Special Issue on Deep
Learning for High-Dimensional Sensing},
Journal = {Ieee Journal of Selected Topics in Signal
Processing},
Volume = {16},
Number = {4},
Pages = {603-607},
Year = {2022},
Month = {June},
url = {http://dx.doi.org/10.1109/JSTSP.2022.3185190},
Doi = {10.1109/JSTSP.2022.3185190},
Key = {fds365215}
}
@article{fds361841,
Author = {Wang, C and Hu, M and Takashima, Y and Schulz, TJ and Brady,
DJ},
Title = {Snapshot ptychography on array cameras.},
Journal = {Optics Express},
Volume = {30},
Number = {2},
Pages = {2585-2598},
Year = {2022},
Month = {January},
url = {http://dx.doi.org/10.1364/oe.447499},
Abstract = {We use convolutional neural networks to recover images
optically down-sampled by 6.7 × using coherent aperture
synthesis over a 16 camera array. Where conventional
ptychography relies on scanning and oversampling, here we
apply decompressive neural estimation to recover full
resolution image from a single snapshot, although as shown
in simulation multiple snapshots can be used to improve
signal-to-noise ratio (SNR). In place training on
experimental measurements eliminates the need to directly
calibrate the measurement system. We also present
simulations of diverse array camera sampling strategies to
explore how snapshot compressive systems might be
optimized.},
Doi = {10.1364/oe.447499},
Key = {fds361841}
}
@article{fds359833,
Author = {Tan, Y and Zheng, H and Zhu, Y and Yuan, X and Lin, X and Brady, D and Fang,
L},
Title = {CrossNet++: Cross-Scale Large-Parallax Warping for
Reference-Based Super-Resolution.},
Journal = {Ieee Transactions on Pattern Analysis and Machine
Intelligence},
Volume = {43},
Number = {12},
Pages = {4291-4305},
Year = {2021},
Month = {December},
url = {http://dx.doi.org/10.1109/tpami.2020.2997007},
Abstract = {The ability of camera arrays to efficiently capture higher
space-bandwidth product than single cameras has led to
various multiscale and hybrid systems. These systems play
vital roles in computational photography, including light
field imaging, 360 VR camera, gigapixel videography, etc.
One of the critical tasks in multiscale hybrid imaging is
matching and fusing cross-resolution images from different
cameras under perspective parallax. In this paper, we
investigate the reference-based super-resolution (RefSR)
problem associated with dual-camera or multi-camera systems.
RefSR consists of super-resolving a low-resolution (LR)
image given an external high-resolution (HR) reference
image, where they suffer both a significant resolution gap (
8×) and large parallax ( ∼ 10% pixel displacement). We
present CrossNet++, an end-to-end network containing novel
two-stage cross-scale warping modules, image encoder and
fusion decoder. The stage I learns to narrow down the
parallax distinctively with the strong guidance of landmarks
and intensity distribution consensus. Then the stage II
operates more fine-grained alignment and aggregation in
feature domain to synthesize the final super-resolved image.
To further address the large parallax, new hybrid loss
functions comprising warping loss, landmark loss and
super-resolution loss are proposed to regularize training
and enable better convergence. CrossNet++ significantly
outperforms the state-of-art on light field datasets as well
as real dual-camera data. We further demonstrate the
generalization of our framework by transferring it to video
super-resolution and video denoising.},
Doi = {10.1109/tpami.2020.2997007},
Key = {fds359833}
}
@article{fds355465,
Author = {Yuan, X and Ji, M and Wu, J and Brady, DJ and Dai, Q and Fang,
L},
Title = {A modular hierarchical array camera},
Journal = {Light: Science and Applications},
Volume = {10},
Number = {1},
Year = {2021},
Month = {December},
url = {http://dx.doi.org/10.1038/s41377-021-00485-x},
Abstract = {Array cameras removed the optical limitations of a single
camera and paved the way for high-performance imaging via
the combination of micro-cameras and computation to fuse
multiple aperture images. However, existing solutions use
dense arrays of cameras that require laborious calibration
and lack flexibility and practicality. Inspired by the
cognition function principle of the human brain, we develop
an unstructured array camera system that adopts a
hierarchical modular design with multiscale hybrid cameras
composing different modules. Intelligent computations are
designed to collaboratively operate along both intra- and
intermodule pathways. This system can adaptively allocate
imagery resources to dramatically reduce the hardware cost
and possesses unprecedented flexibility, robustness, and
versatility. Large scenes of real-world data were acquired
to perform human-centric studies for the assessment of human
behaviours at the individual level and crowd behaviours at
the population level requiring high-resolution long-term
monitoring of dynamic wide-area scenes.},
Doi = {10.1038/s41377-021-00485-x},
Key = {fds355465}
}
@article{fds359530,
Author = {Park, J and Brady, DJ and Zheng, G and Tian, L and Gao,
L},
Title = {Review of bio-optical imaging systems with a high
space-bandwidth product},
Journal = {Advanced Photonics},
Volume = {3},
Number = {4},
Year = {2021},
Month = {July},
url = {http://dx.doi.org/10.1117/1.AP.3.4.044001},
Abstract = {Optical imaging has served as a primary method to collect
information about biosystems across scales-from
functionalities of tissues to morphological structures of
cells and even at biomolecular levels. However, to
adequately characterize a complex biosystem, an imaging
system with a number of resolvable points, referred to as a
space-bandwidth product (SBP), in excess of one billion is
typically needed. Since a gigapixel-scale far exceeds the
capacity of current optical imagers, compromises must be
made to obtain either a low spatial resolution or a narrow
field-of-view (FOV). The problem originates from constituent
refractive optics-the larger the aperture, the more
challenging the correction of lens aberrations. Therefore,
it is impractical for a conventional optical imaging system
to achieve an SBP over hundreds of millions. To address this
unmet need, a variety of high-SBP imagers have emerged over
the past decade, enabling an unprecedented resolution and
FOV beyond the limit of conventional optics. We provide a
comprehensive survey of high-SBP imaging techniques,
exploring their underlying principles and applications in
bioimaging.},
Doi = {10.1117/1.AP.3.4.044001},
Key = {fds359530}
}
@article{fds357030,
Author = {Schulz, TJ and Brady, DJ and Wang, C},
Title = {Photon-limited bounds for phase retrieval.},
Journal = {Optics Express},
Volume = {29},
Number = {11},
Pages = {16736-16748},
Year = {2021},
Month = {May},
url = {http://dx.doi.org/10.1364/oe.425796},
Abstract = {We show that the optimal Cramér-Rao lower bound on the
mean-square error for the estimation of a coherent signal
from photon-limited intensity measurements is equal to the
number of signal elements, or the number of signal elements
minus one when we account for the unobservable reference
phase. Whereas this bound is attained by phase-quadrature
holography, we also show that it can be attained through a
phase-retrieval system that does not require a coherent
reference. We also present the bounds for classic
phase-retrieval and ptychography, and show that practical
coding strategies can approach optimal performance.},
Doi = {10.1364/oe.425796},
Key = {fds357030}
}
@article{fds355585,
Author = {Yuan, X and Brady, DJ and Katsaggelos, AK},
Title = {Snapshot Compressive Imaging: Theory, Algorithms, and
Applications},
Journal = {Ieee Signal Processing Magazine},
Volume = {38},
Number = {2},
Pages = {65-88},
Year = {2021},
Month = {March},
url = {http://dx.doi.org/10.1109/MSP.2020.3023869},
Abstract = {Capturing high-dimensional (HD) data is a long-term
challenge in signal processing and related fields. Snapshot
compressive imaging (SCI) uses a 2D detector to capture HD
(≥3D) data in a snapshot measurement. Via novel optical
designs, the 2D detector samples the HD data in a
compressive manner; following this, algorithms are employed
to reconstruct the desired HD data cube. SCI has been used
in hyperspectral imaging, video, holography, tomography,
focal depth imaging, polarization imaging, microscopy, and
so on. Although the hardware has been investigated for more
than a decade, the theoretical guarantees have only recently
been derived. Inspired by deep learning, various deep neural
networks have also been developed to reconstruct the HD data
cube in spectral SCI and video SCI. This article reviews
recent advances in SCI hardware, theory, and algorithms,
including both optimizationbased and deep learning-based
algorithms. Diverse applications and the outlook for SCI are
also discussed.},
Doi = {10.1109/MSP.2020.3023869},
Key = {fds355585}
}
@article{fds355466,
Author = {Wang, C and Huang, Q and Cheng, M and Ma, Z and Brady,
DJ},
Title = {Deep Learning for Camera Autofocus},
Journal = {Ieee Transactions on Computational Imaging},
Volume = {7},
Pages = {258-271},
Year = {2021},
Month = {January},
url = {http://dx.doi.org/10.1109/TCI.2021.3059497},
Abstract = {Most digital cameras use specialized autofocus sensors, such
as phase detection, lidar or ultrasound, to directly measure
focus state. However, such sensors increase cost and
complexity without directly optimizing final image quality.
This paper proposes a new pipeline for image-based autofocus
and shows that neural image analysis finds focus 5-10x
faster than traditional contrast enhancement. We achieve
this by learning the direct mapping between an image and its
focus position. In further contrast with conventional
methods, AI methods can generate scene-based focus
trajectories that optimize synthesized image quality for
dynamic and three dimensional scenes. We propose a focus
control strategy that varies focal position dynamically to
maximize image quality as estimated from the focal stack. We
propose a rule-based agent and a learned agent for different
scenarios and show their advantages over other focus
stacking methods.},
Doi = {10.1109/TCI.2021.3059497},
Key = {fds355466}
}
@article{fds366468,
Author = {Siddons, DP and Kuczewski, AJ and Rumaiz, AK and Tappero, R and Idir, M and Nakhoda, K and Khanfri, J and Singh, V and Farquhar, ER and Sullivan, M and Abel, D and Brady, DJ and Yuan, X},
Title = {A coded aperture microscope for X-ray fluorescence
full-field imaging.},
Journal = {Journal of Synchrotron Radiation},
Volume = {27},
Number = {Pt 6},
Pages = {1703-1706},
Year = {2020},
Month = {November},
url = {http://dx.doi.org/10.1107/s1600577520012308},
Abstract = {The design and construction of an instrument for full-field
imaging of the X-ray fluorescence emitted by a fully
illuminated sample are presented. The aim is to produce an
X-ray microscope with a few micrometers spatial resolution,
which does not need to scan the sample. Since the
fluorescence from a spatially inhomogeneous sample may
contain many fluorescence lines, the optic which will
provide the magnification of the emissions must be
achromatic, i.e. its optical properties must be
energy-independent. The only optics which fulfill this
requirement in the X-ray regime are mirrors and pinholes.
The throughput of a simple pinhole is very low, so the
concept of coded apertures is an attractive extension which
improves the throughput by having many pinholes, and retains
the achromatic property. Modified uniformly redundant arrays
(MURAs) with 10 µm openings and 50% open area have been
fabricated using gold in a lithographic technique,
fabricated on a 1 µm-thick silicon nitride membrane. The
gold is 25 µm thick, offering good contrast up to
20 keV. The silicon nitride is transparent down into the
soft X-ray region. MURAs with various orders, from 19 up to
73, as well as their respective negative (a mask where open
and closed positions are inversed compared with the original
mask), have been made. Having both signs of mask will reduce
near-field artifacts and make it possible to correct for any
lack of contrast.},
Doi = {10.1107/s1600577520012308},
Key = {fds366468}
}
@article{fds353858,
Author = {Zhang, W and Zhang, H and Cao, L and Gehm, M and Jiang, Q and Brady, DJ and Jin, G},
Title = {Resolution and sampling analysis in digital in-line
holography with spherical wave illumination},
Journal = {Optical Engineering},
Volume = {59},
Number = {10},
Year = {2020},
Month = {October},
url = {http://dx.doi.org/10.1117/1.OE.59.10.102402},
Abstract = {The resolution optimization and sampling strategies in
practical digital in-line holography (DIH) with spherical
wave illumination are analytically studied by optimizing
system parameters. Optimal parameters of holographic
recording, including illumination wavelength, numerical
aperture of the spherical illumination wave, source-sensor
distance, object–sensor distance, and sampling parameters
of the sensor, for achievable resolution are worked out. A
formula is derived to guide the DIH system design in general
cases. Different sampling strategies associated with
corresponding reconstruction waves (plane wave and spherical
waves with various curvatures) are analyzed. The reason why
recording with spherical wave and reconstructing with plane
wave works well in practice is explained in detail. We also
present how to determine the reconstruction distance and
magnification to reconcile the curvature difference. The
analysis is carried out mathematically and verified by
simulated holograms. Optical experiments with U.S. Air Force
resolution target are carried out based on the analysis for
further verification.},
Doi = {10.1117/1.OE.59.10.102402},
Key = {fds353858}
}
@article{fds352846,
Author = {Pang, W and Brady, DJ},
Title = {Distributed focus and digital zoom},
Journal = {Engineering Research Express},
Volume = {2},
Number = {3},
Year = {2020},
Month = {September},
url = {http://dx.doi.org/10.1088/2631-8695/abad0a},
Abstract = {We explore integrated microcamera focus systems for array
cameras. Array cameras enable wide field of view 90° to
360° high resolution (10-100 μrad) imaging with small exit
apertures (≈10mm). Small exit apertures enable compact
focus mechanisms with fast actuators. We show that a common
mechanism supports ≈f/2.5 camera modules with focal
lengths ranging from 25 to 60 mm. Designs for each focal
length include a fixed objective lens group and an
adjustable back focus group. Increasing the focal power of
the front focal group enables the travel range to
accommodate long focal length systems.Wepresent design
examples for both discrete and multiscale array camera
systems.},
Doi = {10.1088/2631-8695/abad0a},
Key = {fds352846}
}
@article{fds349152,
Author = {Zhang, H and Liu, S and Cao, L and Brady, DJ},
Title = {Noise suppression for ballistic-photons based on compressive
in-line holographic imaging through an inhomogeneous
medium.},
Journal = {Optics Express},
Volume = {28},
Number = {7},
Pages = {10337-10349},
Year = {2020},
Month = {March},
url = {http://dx.doi.org/10.1364/oe.385992},
Abstract = {Noise suppression is one of the most important tasks in
imaging through inhomogeneous mediums. Here, we proposed a
denoising approach based on compressive in-line holography
for imaging through an inhomogeneous medium. A
reference-beam-free system with a low-cost continuous-wave
laser is presented. The suppression against the noise, which
is brought by the scattering photons, is presented in
simulations using the proposed algorithm. The noise immunity
is demonstrated in lensless imaging behind a random phase
mask with an optical depth of 1.42 by single exposure, as
well as behind a ground glass with an optical depth of 6.38
by multiple exposures.},
Doi = {10.1364/oe.385992},
Key = {fds349152}
}
@article{fds356507,
Author = {Brady, DJ and Fang, L and Ma, Z},
Title = {Deep learning for camera data acquisition, control, and
image estimation},
Journal = {Advances in Optics and Photonics},
Volume = {12},
Number = {4},
Pages = {787-846},
Year = {2020},
Month = {January},
url = {http://dx.doi.org/10.1364/AOP.398263},
Abstract = {We review the impact of deep-learning technologies on camera
architecture. The function of a camera is first to capture
visual information and second to form an image.
Conventionally, both functions are implemented in physical
optics. Throughout the digital age, however, joint design of
physical sampling and electronic processing, e.g.,
computational imaging, has been increasingly applied to
improve these functions. Over the past five years, deep
learning has radically improved the capacity of
computational imaging. Here we briefly review the
development of artificial neural networks and their recent
intersection with computational imaging. We then consider in
more detail how deep learning impacts the primary strategies
of computational photography: focal plane modulation, lens
design, and robotic control. With focal plane modulation, we
show that deep learning improves signal inference to enable
faster hyperspectral, polarization, and video capture while
reducing the power per pixel by 10-100×. With lens design,
deep learning improves multiple aperture image fusion to
enable task-specific array cameras. With control, deep
learning enables dynamic scene-specific control that may
ultimately enable cameras that capture the entire optical
data cube (the “light field”), rather than just a focal
slice. Finally, we discuss how these three strategies impact
the physical camera design as we seek to balance physical
compactness and simplicity, information capacity,
computational complexity, and visual fidelity.},
Doi = {10.1364/AOP.398263},
Key = {fds356507}
}
@article{fds339270,
Author = {Liu, Y and Yuan, X and Suo, J and Brady, DJ and Dai,
Q},
Title = {Rank Minimization for Snapshot Compressive
Imaging.},
Journal = {Ieee Transactions on Pattern Analysis and Machine
Intelligence},
Volume = {41},
Number = {12},
Pages = {2990-3006},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2019},
Month = {December},
url = {http://dx.doi.org/10.1109/tpami.2018.2873587},
Abstract = {Snapshot compressive imaging (SCI) refers to compressive
imaging systems where multiple frames are mapped into a
single measurement, with video compressive imaging and
hyperspectral compressive imaging as two representative
applications. Though exciting results of high-speed videos
and hyperspectral images have been demonstrated, the poor
reconstruction quality precludes SCI from wide applications.
This paper aims to boost the reconstruction quality of SCI
via exploiting the high-dimensional structure in the desired
signal. We build a joint model to integrate the nonlocal
self-similarity of video/hyperspectral frames and the rank
minimization approach with the SCI sensing process.
Following this, an alternating minimization algorithm is
developed to solve this non-convex problem. We further
investigate the special structure of the sampling process in
SCI to tackle the computational workload and memory issues
in SCI reconstruction. Both simulation and real data
(captured by four different SCI cameras) results demonstrate
that our proposed algorithm leads to significant
improvements compared with current state-of-the-art
algorithms. We hope our results will encourage the
researchers and engineers to pursue further in compressive
imaging for real applications.},
Doi = {10.1109/tpami.2018.2873587},
Key = {fds339270}
}
@article{fds338074,
Author = {Zhang, W and Cao, L and Brady, DJ and Zhang, H and Cang, J and Zhang, H and Jin, G},
Title = {Twin-Image-Free Holography: A Compressive Sensing
Approach.},
Journal = {Physical Review Letters},
Volume = {121},
Number = {9},
Pages = {093902},
Year = {2018},
Month = {August},
url = {http://dx.doi.org/10.1103/physrevlett.121.093902},
Abstract = {Holographic reconstruction is troubled by the
phase-conjugate wave front arising from Hermitian symmetry
of the complex field. The so-called twin image obfuscates
the reconstruction in solving the inverse problem. Here we
quantitatively reveal how and how much the twin image
affects the reconstruction and propose a compressive sensing
(CS) approach to reconstruct a hologram completely free from
the twin image. Using the canonical basis, the incoherence
condition of CS is naturally satisfied by the Fourier
transformation associated with wave propagation. With the
propagation kernel function related to the distance, the
object wave diffracts into a sharp pattern while the
phase-conjugate wave diffracts into a diffuse pattern. An
iterative algorithm using a total variation sparsity
constraint could filter out the diffuse conjugated signal
and overcome the inherent physical symmetry of holographic
reconstruction. The feasibility is verified by simulation
and experimental results, as well as a comparative study to
an existing phase retrieval method.},
Doi = {10.1103/physrevlett.121.093902},
Key = {fds338074}
}
@article{fds337707,
Author = {Pang, W and Brady, DJ},
Title = {Field of view in monocentric multiscale cameras.},
Journal = {Applied Optics},
Volume = {57},
Number = {24},
Pages = {6999-7005},
Year = {2018},
Month = {August},
url = {http://dx.doi.org/10.1364/ao.57.006999},
Abstract = {Conventionally, the field of view of a camera is understood
as the angular extent of a convex circular or rectangular
region. Parallel camera architectures with computational
image stitching, however, allow implementation of a field of
view with an arbitrary shape. Monocentric multiscale lenses
further allow the implementation of an arbitrary field of
view in camera volumes comparable to conventional
single-lens systems. In contrast with conventional
wide-field-of-view systems, multiscale design can also
achieve nearly uniform resolution across the entire field of
view. This paper presents several design studies obtaining
unconventional fields of view using this
approach.},
Doi = {10.1364/ao.57.006999},
Key = {fds337707}
}
@article{fds333254,
Author = {Brady, DJ and Pang, W and Li, H and Ma, Z and Tao, Y and Cao,
X},
Title = {Parallel cameras},
Journal = {Optica},
Volume = {5},
Number = {2},
Pages = {127-137},
Publisher = {The Optical Society},
Year = {2018},
Month = {February},
url = {http://dx.doi.org/10.1364/OPTICA.5.000127},
Abstract = {Parallel lens systems and parallel image signal processing
enable cost efficient and compact cameras to capture
gigapixel scale images. This paper reviews the context of
such cameras in the developing field of computational
imaging and discusses how parallel architectures impact
optical and electronic processing design. Using an array
camera operating system initially developed under the
Defense Advanced Research Projects Agency Advanced Wide FOV
Architectures for Image Reconstruction and Exploitation
program, we illustrate the state of parallel camera
development with example 100 megapixel videos.},
Doi = {10.1364/OPTICA.5.000127},
Key = {fds333254}
}
@article{fds333255,
Author = {Zhang, W and Cao, L and Jin, G and Brady, D},
Title = {Full field-of-view digital lens-free holography for
weak-scattering objects based on grating
modulation.},
Journal = {Applied Optics},
Volume = {57},
Number = {1},
Pages = {A164-A171},
Publisher = {The Optical Society},
Year = {2018},
Month = {January},
url = {http://dx.doi.org/10.1364/ao.57.00a164},
Abstract = {Grating-based single-shot digital lens-free holography with
spatial spectral multiplexing is proposed to realize full
field-of-view (FOV) imaging for weak-scattering objects.
Multiple object waves are generated by a one-dimensional
grating that is placed in near contact with the object to
avoid the cross talk among different diffraction orders
during reconstruction. A multiplexed off-axis hologram is
created by interference between the object waves and
reference wave and captured by an image sensor in one shot.
Multiple imaging areas corresponding to the captured object
waves can be simultaneously retrieved during reconstruction.
A formula which guarantees full FOV imaging without cross
talk or information loss is presented. The imaging
experiments of a USAF resolution target are presented to
demonstrate the feasibility of this method.},
Doi = {10.1364/ao.57.00a164},
Key = {fds333255}
}
@article{fds331443,
Author = {Zhang, H and Cao, L and Zhang, H and Zhang, W and Jin, G and Brady,
DJ},
Title = {Efficient block-wise algorithm for compressive
holography.},
Journal = {Optics Express},
Volume = {25},
Number = {21},
Pages = {24991-25003},
Year = {2017},
Month = {October},
url = {http://dx.doi.org/10.1364/oe.25.024991},
Abstract = {Compressive holography is a relatively time-consuming image
estimation in convex optimized problem. We propose an
efficient block-wise algorithm to limit the searching space
and reduce the calculation time while keeping the
reconstruction quality. The effective anti-aliasing boundary
of the sub-hologram is located to determine the block size
for compressive reconstruction in the total-variation
two-step iterative shrinkage/thresholding algorithm. Padded
sub-holograms could be reconstructed in parallel by using
multi-core processors. Compared with the traditional
compressive holography, the block-wise algorithm could take
approximately 1/50 of the reconstruction time and achieve an
improved reconstruction quality.},
Doi = {10.1364/oe.25.024991},
Key = {fds331443}
}
@article{fds330734,
Author = {Chen, LS and Yue, T and Cao, X and Ma, Z and Brady, DJ},
Title = {High-resolution spectral video acquisition},
Journal = {Frontiers of Information Technology & Electronic
Engineering},
Volume = {18},
Number = {9},
Pages = {1250-1260},
Publisher = {Zhejiang University Press},
Year = {2017},
Month = {September},
url = {http://dx.doi.org/10.1631/FITEE.1700098},
Abstract = {Compared with conventional cameras, spectral imagers provide
many more features in the spectral domain. They have been
used in various fields such as material identification,
remote sensing, precision agriculture, and surveillance.
Traditional imaging spectrometers use generally scanning
systems. They cannot meet the demands of dynamic scenarios.
This limits the practical applications for spectral imaging.
Recently, with the rapid development in computational
photography theory and semiconductor techniques, spectral
video acquisition has become feasible. This paper aims to
offer a review of the state-of-the-art spectral imaging
technologies, especially those capable of capturing spectral
videos. Finally, we evaluate the performances of the
existing spectral acquisition systems and discuss the trends
for future work.},
Doi = {10.1631/FITEE.1700098},
Key = {fds330734}
}
@article{fds330735,
Author = {Pang, W and Brady, DJ},
Title = {Galilean monocentric multiscale optical systems.},
Journal = {Optics Express},
Volume = {25},
Number = {17},
Pages = {20332-20339},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1364/oe.25.020332},
Abstract = {The first generation of monocentric multiscale gigapixel
cameras used Keplerian designs to enable full field
coverage. This paper considers alternative designs that
remove the requirement that adjacent subimages overlap.
Removing this constraint enables Galilean designs that
reduce system volume and improve relative illumination and
image quality. The entrance aperture can also be moved to
more closely approximate telecentricity and gaps in the
field of view can be filled using multiple co-boresighted
MMS cameras. Even with multiple cameras, Galilean systems
can still reduce the total volume by 10 times relative to
previous Keplerian designs.},
Doi = {10.1364/oe.25.020332},
Key = {fds330735}
}
@article{fds330736,
Author = {Zhao, Y and Yue, T and Chen, L and Wang, H and Ma, Z and Brady, DJ and Cao,
X},
Title = {Heterogeneous camera array for multispectral light field
imaging.},
Journal = {Optics Express},
Volume = {25},
Number = {13},
Pages = {14008-14022},
Year = {2017},
Month = {June},
url = {http://dx.doi.org/10.1364/oe.25.014008},
Abstract = {Multispectral light field acquisition is challenging due to
the increased dimensionality of the problem. In this paper,
inspired by anaglyph theory (i.e. the ability of human eyes
to synthesize colored stereo perception from
color-complementary (such as red and cyan) views), we
propose to capture the multispectral light field using
multiple cameras with different wide band filters. A
convolutional neural network is used to extract the joint
information of different spectral channels and to pair the
cross-channel images. In our experiment, results on both
synthetic data and real data captured by our prototype
system validate the effectiveness and accuracy of proposed
method.},
Doi = {10.1364/oe.25.014008},
Key = {fds330736}
}
@article{fds330166,
Author = {Amsden, JJ and Gehm, ME and Russell, ZE and Chen, EX and Di Dona and ST and Wolter, SD and Danell, RM and Kibelka, G and Parker, CB and Stoner, BR and Brady, DJ and Glass, JT},
Title = {Coded Apertures in Mass Spectrometry.},
Journal = {Annual Review of Analytical Chemistry (Palo Alto,
Calif.)},
Volume = {10},
Number = {1},
Pages = {141-156},
Year = {2017},
Month = {June},
url = {http://dx.doi.org/10.1146/annurev-anchem-061516-045256},
Abstract = {The use of coded apertures in mass spectrometry can break
the trade-off between throughput and resolution that has
historically plagued conventional instruments. Despite their
very early stage of development, coded apertures have been
shown to increase throughput by more than one order of
magnitude, with no loss in resolution in a simple 90-degree
magnetic sector. This enhanced throughput can increase the
signal level with respect to the underlying noise, thereby
significantly improving sensitivity to low concentrations of
analyte. Simultaneous resolution can be maintained,
preventing any decrease in selectivity. Both one- and
two-dimensional (2D) codes have been demonstrated. A 2D code
can provide increased measurement diversity and therefore
improved numerical conditioning of the mass spectrum that is
reconstructed from the coded signal. This review discusses
the state of development, the applications where coding is
expected to provide added value, and the various instrument
modifications necessary to implement coded apertures in mass
spectrometers.},
Doi = {10.1146/annurev-anchem-061516-045256},
Key = {fds330166}
}
@article{fds331204,
Author = {Gollub, JN and Yurduseven, O and Trofatter, KP and Arnitz, D and F
Imani, M and Sleasman, T and Boyarsky, M and Rose, A and Pedross-Engel,
A and Odabasi, H and Zvolensky, T and Lipworth, G and Brady, D and Marks,
DL and Reynolds, MS and Smith, DR},
Title = {Large Metasurface Aperture for Millimeter Wave Computational
Imaging at the Human-Scale.},
Journal = {Scientific Reports},
Volume = {7},
Pages = {42650},
Year = {2017},
Month = {February},
url = {http://dx.doi.org/10.1038/srep42650},
Abstract = {We demonstrate a low-profile holographic imaging system at
millimeter wavelengths based on an aperture composed of
frequency-diverse metasurfaces. Utilizing measurements of
spatially-diverse field patterns, diffraction-limited images
of human-sized subjects are reconstructed. The system is
driven by a single microwave source swept over a band of
frequencies (17.5-26.5 GHz) and switched between a
collection of transmit and receive metasurface panels. High
fidelity image reconstruction requires a precise model for
each field pattern generated by the aperture, as well as the
manner in which the field scatters from objects in the
scene. This constraint makes scaling of computational
imaging systems inherently challenging for electrically
large, coherent apertures. To meet the demanding
requirements, we introduce computational methods and
calibration approaches that enable rapid and accurate
imaging performance.},
Doi = {10.1038/srep42650},
Key = {fds331204}
}
@article{fds330187,
Author = {Zhu, R and Richard, JT and Brady, DJ and Marks, DL and Everitt,
HO},
Title = {Compressive sensing and adaptive sampling applied to
millimeter wave inverse synthetic aperture
imaging.},
Journal = {Optics Express},
Volume = {25},
Number = {3},
Pages = {2270-2284},
Publisher = {The Optical Society},
Year = {2017},
Month = {February},
url = {http://dx.doi.org/10.1364/oe.25.002270},
Abstract = {In order to improve speed and efficiency over traditional
scanning methods, a Bayesian compressive sensing algorithm
using adaptive spatial sampling is developed for single
detector millimeter wave synthetic aperture imaging. The
application of this algorithm is compared to random sampling
to demonstrate that the adaptive algorithm converges faster
for simple targets and generates more reliable
reconstructions for complex targets.},
Doi = {10.1364/oe.25.002270},
Key = {fds330187}
}
@article{fds322144,
Author = {Cao, X and Yue, T and Lin, X and Lin, S and Yuan, X and Dai, Q and Carin, L and Brady, DJ},
Title = {Computational Snapshot Multispectral Cameras: Toward dynamic
capture of the spectral world},
Journal = {Ieee Signal Processing Magazine},
Volume = {33},
Number = {5},
Pages = {95-108},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1109/MSP.2016.2582378},
Abstract = {Multispectral cameras collect image data with a greater
number of spectral channels than traditional trichromatic
sensors, thus providing spectral information at a higher
level of detail. Such data are useful in various fields,
such as remote sensing, materials science, biophotonics, and
environmental monitoring. The massive scale of multispectral
data-at high resolutions in the spectral, spatial, and
temporal dimensions-has long presented a major challenge in
spectrometer design. With recent developments in sampling
theory, this problem has become more manageable through use
of undersampling and constrained reconstruction techniques.
This article presents an overview of these state-of-the-art
multispectral acquisition systems, with a particular focus
on snapshot multispectral capture, from a signal processing
perspective. We propose that undersampling-based
multispectral cameras can be understood and compared by
examining the efficiency of their sampling schemes, which we
formulate as the spectral sensing coherence information
between their sensing matrices and spectrum-specific bases
learned from a large-scale multispectral image database. We
analyze existing snapshot multispectral cameras in this
manner, and additionally discuss their optical performance
in terms of light throughput and system complexity.},
Doi = {10.1109/MSP.2016.2582378},
Key = {fds322144}
}
@article{fds322145,
Author = {Yuan, X and Liao, X and Llull, P and Brady, D and Carin,
L},
Title = {Efficient patch-based approach for compressive depth
imaging.},
Journal = {Applied Optics},
Volume = {55},
Number = {27},
Pages = {7556-7564},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1364/ao.55.007556},
Abstract = {We present efficient camera hardware and algorithms to
capture images with extended depth of field. The camera
moves its focal plane via a liquid lens and modulates the
scene at different focal planes by shifting a fixed binary
mask, with synchronization achieved by using the same
triangular wave to control the focal plane and the
pizeoelectronic translator that shifts the mask. Efficient
algorithms are developed to reconstruct the all-in-focus
image and the depth map from a single coded exposure, and
various sparsity priors are investigated to enhance the
reconstruction, including group sparsity, tree structure,
and dictionary learning. The algorithms naturally admit a
parallel computational structure due to the independent
patch-level operations. Experimental results on both
simulation and real datasets demonstrate the efficacy of the
new hardware and the inversion algorithms.},
Doi = {10.1364/ao.55.007556},
Key = {fds322145}
}
@article{fds323368,
Author = {Hassan, M and Greenberg, JA and Odinaka, I and Brady,
DJ},
Title = {Snapshot fan beam coded aperture coherent scatter
tomography.},
Journal = {Optics Express},
Volume = {24},
Number = {16},
Pages = {18277-18289},
Year = {2016},
Month = {August},
url = {http://dx.doi.org/10.1364/oe.24.018277},
Abstract = {We use coherently scattered X-rays to measure the molecular
composition of an object throughout its volume. We image a
planar slice of the object in a single snapshot by
illuminating it with a fan beam and placing a coded aperture
between the object and the detectors. We characterize the
system and demonstrate a resolution of 13 mm in range and 2
mm in cross-range and a fractional momentum transfer
resolution of 15%. In addition, we show that this technique
allows a 100x speedup compared to previously-studied pencil
beam systems using the same components. Finally, by scanning
an object through the beam, we image the full 4-dimensional
data cube (3 spatial and 1 material dimension) for complete
volumetric molecular imaging.},
Doi = {10.1364/oe.24.018277},
Key = {fds323368}
}
@article{fds323369,
Author = {Nichols, JM and Judd, KP and Olson, CC and Novak, K and Waterman, JR and Feller, S and McCain, S and Anderson, J and Brady,
D},
Title = {Range performance of the DARPA AWARE wide field-of-view
visible imager.},
Journal = {Applied Optics},
Volume = {55},
Number = {16},
Pages = {4478-4484},
Publisher = {The Optical Society},
Year = {2016},
Month = {June},
url = {http://dx.doi.org/10.1364/ao.55.004478},
Abstract = {In a prior paper, we described a new imaging architecture
that addresses the need for wide field-of-view imaging
combined with the resolution required to identify targets at
long range. Over the last two years substantive improvements
have been made to the system, both in terms of the size,
weight, and power of the camera as well as to the optics and
data management software. The result is an overall
improvement in system performance, which we demonstrate via
a maritime target identification experiment.},
Doi = {10.1364/ao.55.004478},
Key = {fds323369}
}
@article{fds323375,
Author = {Llull, P and Bange, L and Phillips, Z and Davis, K and Marks, DL and Brady,
DJ},
Title = {Characterization of the AWARE 40 wide-field-of-view visible
imager},
Journal = {Optica},
Volume = {2},
Number = {12},
Pages = {1086-1089},
Publisher = {The Optical Society},
Year = {2015},
Month = {December},
url = {http://dx.doi.org/10.1364/OPTICA.2.001086},
Abstract = {High-resolution, wide-field-of-view photography has
undergone substantial improvements since the advent of
multiscale lens design. Here, we present and evaluate a
multiscale camera capable of a 10 μrad instantaneous field
of view over a 36° field of view. We experimentally verify
this camera’s optical performance at the individual
microcamera level and report a 2.4 gigapixel panorama
stitched from five snapshots. The results are consistent
with the use of parallel camera arrays to produce scalable
imagery at a substantial resolution range.},
Doi = {10.1364/OPTICA.2.001086},
Key = {fds323375}
}
@article{fds280203,
Author = {Brady, DJ and Mrozack, A and MacCabe, K and Llull,
P},
Title = {Compressive tomography},
Journal = {Advances in Optics and Photonics},
Volume = {7},
Number = {4},
Pages = {756-813},
Publisher = {The Optical Society},
Year = {2015},
Month = {November},
url = {http://dx.doi.org/10.1364/AOP.7.000756},
Abstract = {Compressive tomography consists of estimation of
high-dimensional objects from lower dimensional
measurements. We review compressive tomography using
radiation fields, including geometric, wave, and statistical
field models. We find coded apertures most appropriate for
compressive coding with geometric models, spatial and
frequency subsampling most appropriate for wave models, and
temporal modulation most appropriate for statistical models.
In each case, we show that compressive measurement enables
snapshot 3D imaging, eliminating or reducing the need to
sacrifice temporal resolution in multidimensional
imaging.},
Doi = {10.1364/AOP.7.000756},
Key = {fds280203}
}
@article{fds323551,
Author = {Marks, DL and Bange, LM and Brady, DJ},
Title = {Feedback stitching for gigapixel video},
Journal = {Journal of Electronic Imaging},
Volume = {24},
Number = {6},
Pages = {063006-063006},
Publisher = {SPIE-Intl Soc Optical Eng},
Year = {2015},
Month = {November},
url = {http://dx.doi.org/10.1117/1.JEI.24.6.063006},
Abstract = {Methods of stitching static panoramas are unsuitable for
video-rate stitching from camera arrays, because these
methods are too computationally intensive for real-time
operation and do not take advantage of prior knowledge of
camera positions or the coherence between successive frames
of a video sequence. We propose feedback stitching, which
embeds the stitching process in a feedback loop, so that as
new frames are captured, any new stitching errors occurring
in the video sequence are analyzed and corrected as the
sequence progresses. These algorithms are suitable for
multiscale cameras, a camera array technology proven to be
capable of gigapixel snapshot and video imaging, to allow
for real-time compensation of any registration or parallax
errors.},
Doi = {10.1117/1.JEI.24.6.063006},
Key = {fds323551}
}
@article{fds291360,
Author = {Kaganovsky, Y and Han, S and Degirmenci, S and Politte, DG and Brady,
DJ and O’Sullivan, JA and Carin, L},
Title = {Alternating minimization algorithm with automatic relevance
determination for transmission tomography under poisson
noise},
Journal = {Siam Journal on Imaging Sciences},
Volume = {8},
Number = {3},
Pages = {2087-2132},
Publisher = {Society for Industrial & Applied Mathematics
(SIAM)},
Year = {2015},
Month = {September},
url = {http://dx.doi.org/10.1137/141000038},
Abstract = {We propose a globally convergent alternating minimization
(AM) algorithm for image reconstruction in transmission
tomography, which extends automatic relevance determination
(ARD) to Poisson noise models with Beer’s law. The
algorithm promotes solutions that are sparse in the
pixel/voxel– difference domain by introducing additional
latent variables, one for each pixel/voxel, and then
learning these variables from the data using a hierarchical
Bayesian model. Importantly, the proposed AM algorithm is
free of any tuning parameters with image quality comparable
to standard penalized likelihood methods. Our algorithm
exploits optimization transfer principles which reduce the
problem into parallel one-dimensional optimization tasks
(one for each pixel/voxel), making the algorithm feasible
for large-scale problems. This approach considerably reduces
the computational bottleneck of ARD associated with the
posterior variances. Positivity constraints inherent in
transmission tomography problems are also enforced. We
demonstrate the performance of the proposed algorithm for
x-ray computed tomography using synthetic and real-world
datasets. The algorithm is shown to have much better
performance than prior ARD algorithms based on approximate
Gaussian noise models, even for high photon flux. Sample
code is available from http://www.yankaganovsky.
com/#!code/c24bp.},
Doi = {10.1137/141000038},
Key = {fds291360}
}
@article{fds322148,
Author = {Llull, P and Yuan, X and Carin, L and Brady, DJ},
Title = {Image translation for single-shot focal tomography},
Journal = {Optica},
Volume = {2},
Number = {9},
Pages = {822-825},
Publisher = {The Optical Society},
Year = {2015},
Month = {September},
url = {http://dx.doi.org/10.1364/OPTICA.2.000822},
Abstract = {Focus and depth of field are conventionally addressed by
adjusting longitudinal lens position. More recently,
combinations of deliberate blur and computational processing
have been used to extend depth of field. Here we show that
dynamic control of transverse and longitudinal lens position
can be used to decode focus and extend depth of field
without degrading static resolution. Our results suggest
that optical image stabilization systems may be used for
autofocus, extended depth of field, and 3D
imaging.},
Doi = {10.1364/OPTICA.2.000822},
Key = {fds322148}
}
@article{fds291359,
Author = {Wang, L and Huang, J and Yuan, X and Krishnamurthy, K and Greenberg, J and Cevher, V and Rodrigues, MRD and Brady, D and Calderbank, R and Carin,
L},
Title = {Signal recovery and system calibration from multiple
compressive poisson measurements},
Journal = {Siam Journal on Imaging Sciences},
Volume = {8},
Number = {3},
Pages = {1923-1954},
Publisher = {Society for Industrial & Applied Mathematics
(SIAM)},
Year = {2015},
Month = {September},
url = {http://dx.doi.org/10.1137/140998779},
Abstract = {The measurement matrix employed in compressive sensing
typically cannot be known precisely a priori and must be
estimated via calibration. One may take multiple compressive
measurements, from which the measurement matrix and
underlying signals may be estimated jointly. This is of
interest as well when the measurement matrix may change as a
function of the details of what is measured. This problem
has been considered recently for Gaussian measurement noise,
and here we develop this idea with application to Poisson
systems. A collaborative maximum likelihood algorithm and
alternating proximal gradient algorithm are proposed, and
associated theoretical performance guarantees are
established based on newly derived concentration-of-measure
results. A Bayesian model is then introduced, to improve
flexibility and generality. Connections between the maximum
likelihood methods and the Bayesian model are developed, and
example results are presented for a real compressive X-ray
imaging system.},
Doi = {10.1137/140998779},
Key = {fds291359}
}
@article{fds280128,
Author = {Yuan, X and Tsai, TH and Zhu, R and Llull, P and Brady, D and Carin,
L},
Title = {Compressive hyperspectral imaging with side
information},
Journal = {Ieee Journal of Selected Topics in Signal
Processing},
Volume = {9},
Number = {6},
Pages = {964-976},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {September},
ISSN = {1932-4553},
url = {http://dx.doi.org/10.1109/JSTSP.2015.2411575},
Abstract = {A blind compressive sensing algorithm is proposed to
reconstruct hyperspectral images from spectrally-compressed
measurements. The wavelength-dependent data are coded and
then superposed, mapping the three-dimensional hyperspectral
datacube to a two-dimensional image. The inversion algorithm
learns a dictionary in situ from the measurements via
global-local shrinkage priors. By using RGB images as side
information of the compressive sensing system, the proposed
approach is extended to learn a coupled dictionary from the
joint dataset of the compressed measurements and the
corresponding RGB images, to improve reconstruction quality.
A prototype camera is built using a liquid-crystal-on-silicon
modulator. Experimental reconstructions of hyperspectral
datacubes from both simulated and real compressed
measurements demonstrate the efficacy of the proposed
inversion algorithm, the feasibility of the camera and the
benefit of side information.},
Doi = {10.1109/JSTSP.2015.2411575},
Key = {fds280128}
}
@article{fds280129,
Author = {Tsai, T-H and Llull, P and Yuan, X and Carin, L and Brady,
DJ},
Title = {Spectral-temporal compressive imaging.},
Journal = {Optics Letters},
Volume = {40},
Number = {17},
Pages = {4054-4057},
Year = {2015},
Month = {September},
ISSN = {0146-9592},
url = {http://dx.doi.org/10.1364/ol.40.004054},
Abstract = {This Letter presents a compressive camera that integrates
mechanical translation and spectral dispersion to compress a
multi-spectral, high-speed scene onto a monochrome,
video-rate detector. Experimental reconstructions of 17
spectral channels and 11 temporal channels from a single
measurement are reported for a megapixel-scale monochrome
camera.},
Doi = {10.1364/ol.40.004054},
Key = {fds280129}
}
@article{fds280132,
Author = {Chen, EX and Russell, ZE and Amsden, JJ and Wolter, SD and Danell, RM and Parker, CB and Stoner, BR and Gehm, ME and Glass, JT and Brady,
DJ},
Title = {Order of Magnitude Signal Gain in Magnetic Sector Mass
Spectrometry Via Aperture Coding.},
Journal = {Journal of the American Society for Mass
Spectrometry},
Volume = {26},
Number = {9},
Pages = {1633-1640},
Year = {2015},
Month = {September},
ISSN = {1044-0305},
url = {http://dx.doi.org/10.1007/s13361-015-1178-y},
Abstract = {Miniaturizing instruments for spectroscopic applications
requires the designer to confront a tradeoff between
instrument resolution and instrument throughput [and
associated signal-to-background-ratio (SBR)]. This work
demonstrates a solution to this tradeoff in sector mass
spectrometry by the first application of one-dimensional
(1D) spatially coded apertures, similar to those previously
demonstrated in optics. This was accomplished by replacing
the input slit of a simple 90° magnetic sector mass
spectrometer with a specifically designed coded aperture,
deriving the corresponding forward mathematical model and
spectral reconstruction algorithm, and then utilizing the
resulting system to measure and reconstruct the mass spectra
of argon, acetone, and ethanol. We expect the application of
coded apertures to sector instrument designs will lead to
miniature mass spectrometers that maintain the high
performance of larger instruments, enabling field detection
of trace chemicals and point-of-use mass
spectrometry.},
Doi = {10.1007/s13361-015-1178-y},
Key = {fds280132}
}
@article{fds280130,
Author = {Xie, Y and Tsai, T-H and Konneker, A and Popa, B-I and Brady, DJ and Cummer, SA},
Title = {Single-sensor multispeaker listening with acoustic
metamaterials.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {112},
Number = {34},
Pages = {10595-10598},
Year = {2015},
Month = {August},
ISSN = {0027-8424},
url = {http://dx.doi.org/10.1073/pnas.1502276112},
Abstract = {Designing a "cocktail party listener" that functionally
mimics the selective perception of a human auditory system
has been pursued over the past decades. By exploiting
acoustic metamaterials and compressive sensing, we present
here a single-sensor listening device that separates
simultaneous overlapping sounds from different sources. The
device with a compact array of resonant metamaterials is
demonstrated to distinguish three overlapping and
independent sources with 96.67% correct audio recognition.
Segregation of the audio signals is achieved using physical
layer encoding without relying on source characteristics.
This hardware approach to multichannel source separation can
be applied to robust speech recognition and hearing aids and
may be extended to other acoustic imaging and sensing
applications.},
Doi = {10.1073/pnas.1502276112},
Key = {fds280130}
}
@article{fds291362,
Author = {Tsai, T-H and Yuan, X and Brady, DJ},
Title = {Spatial light modulator based color polarization
imaging.},
Journal = {Optics Express},
Volume = {23},
Number = {9},
Pages = {11912-11926},
Year = {2015},
Month = {May},
url = {http://dx.doi.org/10.1364/oe.23.011912},
Abstract = {We describe a compressive snapshot color polarization imager
that encodes spatial, spectral, and polarization information
using a liquid crystal modulator. We experimentally show
that polarization imaging is compressible by multiplexing
polarization states and present the reconstruction results.
This compressive camera captures the spatial distribution of
four polarizations and three color channels. It achieves
<0.027° spatial resolution, 10(3) average extinction ratio,
and >30 PSNR.},
Doi = {10.1364/oe.23.011912},
Key = {fds291362}
}
@article{fds280133,
Author = {Gehm, ME and Brady, DJ},
Title = {Compressive sensing in the EO/IR.},
Journal = {Applied Optics},
Volume = {54},
Number = {8},
Pages = {C14-C22},
Year = {2015},
Month = {March},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/ao.54.000c14},
Abstract = {We investigate the utility of compressive sensing (CS) to
electro-optic and infrared (EO/IR) applications. We
introduce the field through a discussion of historical
antecedents and the development of the modern CS framework.
Basic economic arguments (in the broadest sense) are
presented regarding the applicability of CS to the EO/IR and
used to draw conclusions regarding application areas where
CS would be most viable. A number of experimental success
stories are presented to demonstrate the overall feasibility
of the approaches, and we conclude with a discussion of open
challenges to practical adoption of CS methods.},
Doi = {10.1364/ao.54.000c14},
Key = {fds280133}
}
@article{fds280137,
Author = {Russell, ZE and Chen, EX and Amsden, JJ and Wolter, SD and Danell, RM and Parker, CB and Stoner, BR and Gehm, ME and Brady, DJ and Glass,
JT},
Title = {Two-dimensional aperture coding for magnetic sector mass
spectrometry.},
Journal = {Journal of the American Society for Mass
Spectrometry},
Volume = {26},
Number = {2},
Pages = {248-256},
Year = {2015},
Month = {February},
ISSN = {1044-0305},
url = {http://dx.doi.org/10.1007/s13361-014-1051-4},
Abstract = {In mass spectrometer design, there has been a historic
belief that there exists a fundamental trade-off between
instrument size, throughput, and resolution. When
miniaturizing a traditional system, performance loss in
either resolution or throughput would be expected. However,
in optical spectroscopy, both one-dimensional (1D) and
two-dimensional (2D) aperture coding have been used for many
years to break a similar trade-off. To provide a viable path
to miniaturization for harsh environment field applications,
we are investigating similar concepts in sector mass
spectrometry. Recently, we demonstrated the viability of 1D
aperture coding and here we provide a first investigation of
2D coding. In coded optical spectroscopy, 2D coding is
preferred because of increased measurement diversity for
improved conditioning and robustness of the result. To
investigate its viability in mass spectrometry, analytes of
argon, acetone, and ethanol were detected using a custom
90-degree magnetic sector mass spectrometer incorporating 2D
coded apertures. We developed a mathematical forward model
and reconstruction algorithm to successfully reconstruct the
mass spectra from the 2D spatially coded ion positions. This
2D coding enabled a 3.5× throughput increase with minimal
decrease in resolution. Several challenges were overcome in
the mass spectrometer design to enable this coding,
including the need for large uniform ion flux, a wide gap
magnetic sector that maintains field uniformity, and a high
resolution 2D detection system for ion imaging. Furthermore,
micro-fabricated 2D coded apertures incorporating support
structures were developed to provide a viable design that
allowed ion transmission through the open elements of the
code.},
Doi = {10.1007/s13361-014-1051-4},
Key = {fds280137}
}
@article{fds280135,
Author = {Yang, J and Liao, X and Yuan, X and Llull, P and Brady, DJ and Sapiro, G and Carin, L},
Title = {Compressive sensing by learning a Gaussian mixture model
from measurements.},
Journal = {Ieee Transactions on Image Processing : a Publication of the
Ieee Signal Processing Society},
Volume = {24},
Number = {1},
Pages = {106-119},
Year = {2015},
Month = {January},
ISSN = {1057-7149},
url = {http://dx.doi.org/10.1109/tip.2014.2365720},
Abstract = {Compressive sensing of signals drawn from a Gaussian mixture
model (GMM) admits closed-form minimum mean squared error
reconstruction from incomplete linear measurements. An
accurate GMM signal model is usually not available a priori,
because it is difficult to obtain training signals that
match the statistics of the signals being sensed. We propose
to solve that problem by learning the signal model in situ,
based directly on the compressive measurements of the
signals, without resorting to other signals to train a
model. A key feature of our method is that the signals being
sensed are treated as random variables and are integrated
out in the likelihood. We derive a maximum marginal
likelihood estimator (MMLE) that maximizes the likelihood of
the GMM of the underlying signals given only their linear
compressive measurements. We extend the MMLE to a GMM with
dominantly low-rank covariance matrices, to gain
computational speedup. We report extensive experimental
results on image inpainting, compressive sensing of
high-speed video, and compressive hyperspectral imaging (the
latter two based on real compressive cameras). The results
demonstrate that the proposed methods outperform
state-of-the-art methods by significant margins.},
Doi = {10.1109/tip.2014.2365720},
Key = {fds280135}
}
@article{fds280125,
Author = {Zhu, R and Furxhi, O and Marks, D and Brady, D},
Title = {Millimeter wave surface and reflectivity estimation based on
sparse time of flight measurements},
Journal = {International Conference on Infrared, Millimeter, and
Terahertz Waves, Irmmw Thz},
Publisher = {IEEE},
Year = {2014},
Month = {November},
ISSN = {2162-2027},
url = {http://dx.doi.org/10.1109/IRMMW-THz.2014.6956301},
Abstract = {We present a novel active millimeter wave imaging technique
that can be used to estimate target surface and
reflectivity. This technique requires no mechanical scanning
but requires only a sparse array of detectors. The
illumination beam requires no focusing or collimation. The
reconstruction is based on the time of flight information
from the reflected signal.},
Doi = {10.1109/IRMMW-THz.2014.6956301},
Key = {fds280125}
}
@article{fds280144,
Author = {Yang, J and Yuan, X and Liao, X and Llull, P and Brady, DJ and Sapiro, G and Carin, L},
Title = {Video compressive sensing using Gaussian mixture
models.},
Journal = {Ieee Transactions on Image Processing : a Publication of the
Ieee Signal Processing Society},
Volume = {23},
Number = {11},
Pages = {4863-4878},
Year = {2014},
Month = {November},
ISSN = {1057-7149},
url = {http://dx.doi.org/10.1109/tip.2014.2344294},
Abstract = {A Gaussian mixture model (GMM)-based algorithm is proposed
for video reconstruction from temporally compressed video
measurements. The GMM is used to model spatio-temporal video
patches, and the reconstruction can be efficiently computed
based on analytic expressions. The GMM-based inversion
method benefits from online adaptive learning and parallel
computation. We demonstrate the efficacy of the proposed
inversion method with videos reconstructed from simulated
compressive video measurements, and from a real compressive
video camera. We also use the GMM as a tool to investigate
adaptive video compressive sensing, i.e., adaptive rate of
temporal compression.},
Doi = {10.1109/tip.2014.2344294},
Key = {fds280144}
}
@article{fds280145,
Author = {Hunt, J and Gollub, J and Driscoll, T and Lipworth, G and Mrozack, A and Reynolds, MS and Brady, DJ and Smith, DR},
Title = {Metamaterial microwave holographic imaging
system.},
Journal = {Journal of the Optical Society of America
A},
Volume = {31},
Number = {10},
Pages = {2109-2119},
Year = {2014},
Month = {October},
ISSN = {1084-7529},
url = {http://dx.doi.org/10.1364/josaa.31.002109},
Abstract = {We demonstrate a microwave imaging system that combines
advances in metamaterial aperture design with emerging
computational imaging techniques. The flexibility inherent
to guided-wave, complementary metamaterials enables the
design of a planar antenna that illuminates a scene with
dramatically varying radiation patterns as a function of
frequency. As frequency is swept over the K-band
(17.5-26.5 GHz), a sequence of pseudorandom radiation
patterns interrogates a scene. Measurements of the return
signal versus frequency are then acquired and the scene is
reconstructed using computational imaging methods. The
low-cost, frequency-diverse static aperture allows
three-dimensional images to be formed without mechanical
scanning or dynamic beam-forming elements. The metamaterial
aperture is complementary to a variety of computational
imaging schemes, and can be used in conjunction with other
sensors to form a multifunctional imaging platform. We
illustrate the potential of multisensor fusion by
integrating an infrared structured-light and optical image
sensor to accelerate the microwave scene reconstruction and
to provide a simultaneous visualization of the
scene.},
Doi = {10.1364/josaa.31.002109},
Key = {fds280145}
}
@article{fds280150,
Author = {Lakshmanan, MN and Kapadia, AJ and Sahbaee, P and Wolter, SD and Harrawood, BP and Brady, D and Samei, E},
Title = {An X-ray scatter system for material identification in
cluttered objects: A Monte Carlo simulation
study},
Journal = {Nuclear Instruments and Methods in Physics Research Section
B: Beam Interactions With Materials and Atoms},
Volume = {335},
Pages = {31-38},
Publisher = {Elsevier BV},
Year = {2014},
Month = {September},
ISSN = {0168-583X},
url = {http://dx.doi.org/10.1016/j.nimb.2014.05.021},
Abstract = {The analysis of X-ray scatter patterns has been demonstrated
as an effective method of identifying specific materials in
mixed object environments, for both biological and
non-biological applications. Here we describe an X-ray
scatter imaging system for material identification in
cluttered objects and investigate its performance using a
large-scale Monte Carlo simulation study of one-thousand
objects containing a broad array of materials. The Geant4
Monte Carlo source code for Rayleigh scatter physics was
modified to model coherent scatter diffraction in bulk
materials based on experimentally measured form factors for
33 materials. The simulation was then used to model coherent
scatter signals from a variety of targets and clutter
(background) materials in one thousand randomized objects.
The resulting scatter images were used to characterize four
parameters of the imaging system that affected its ability
to identify target materials: (a) the arrangement of
materials in the object, (b) clutter attenuation, (c) type
of target material, and (d) the X-ray tube current. We found
that the positioning of target materials within the object
did not significantly affect their detectability; however, a
strong negative correlation was observed between the target
detectability and the clutter attenuation of the object. The
imaging signal was also found to be relatively invariant to
increases in X-ray tube current above 1 mAs for most
materials considered in the study. This work is the first
Monte Carlo study to our knowledge of a large population of
cluttered object of an X-ray scatter imaging system for
material identification and lays the foundation for
large-scale studies of the effectiveness of X-ray scatter
imaging systems for material identification in complex
samples. © 2014 Elsevier B.V. All rights
reserved.},
Doi = {10.1016/j.nimb.2014.05.021},
Key = {fds280150}
}
@article{fds280143,
Author = {Pang, S and Hassan, M and Greenberg, J and Holmgren, A and Krishnamurthy, K and Brady, D},
Title = {Complementary coded apertures for 4-dimensional x-ray
coherent scatter imaging.},
Journal = {Optics Express},
Volume = {22},
Number = {19},
Pages = {22925-22936},
Year = {2014},
Month = {September},
url = {http://dx.doi.org/10.1364/oe.22.022925},
Abstract = {X-ray scattering has played a key role in non-destructive
materials characterization due to the material-specific
coherent scattering signatures. In the current energy
dispersive coherent scatter imaging systems, including
selected volume tomography and coherent scatter computed
tomography, each object voxel is measured at a single
scatter angle, which suffers from slow acquisition time. The
employment of coded apertures in x-ray scatter imaging
systems improves the photon collection efficiency, making it
promising for real time volumetric imaging and material
identification. In this paper, we propose a volumetric x-ray
scatter imaging system using a pair of complementary coded
apertures: a coded aperture on the detector side introduces
multiplexed measurement on an energy-sensitive detector
array; a complementary source-side coded aperture
selectively illuminates the object to decouple the ambiguity
due to the increased parallelization for 4D imaging. The
system yields the 1D coherent scattering form factor at each
voxel in 3D. We demonstrate tomographic imaging and material
identification with the system and achieve a spatial
resolution ~1 cm and a normalized momentum transfer
resolution, Δq/q, of 0.2.},
Doi = {10.1364/oe.22.022925},
Key = {fds280143}
}
@article{fds280148,
Author = {Chen, EX and Gehm, M and Danell, R and Wells, M and Glass, JT and Brady,
D},
Title = {Compressive mass analysis on quadrupole ion trap
systems.},
Journal = {Journal of the American Society for Mass
Spectrometry},
Volume = {25},
Number = {7},
Pages = {1295-1304},
Year = {2014},
Month = {July},
ISSN = {1044-0305},
url = {http://dx.doi.org/10.1007/s13361-014-0894-z},
Abstract = {Conventionally, quadrupole ion trap mass spectrometers eject
ions of different mass-to-charge ratio (m/z) in a sequential
fashion by performing a scan of the rf trapping voltage
amplitude. Due to the inherent sparsity of most mass
spectra, the detector measures no signal for much of the
scan time. By exploiting this sparsity property, we propose
a new compressive and multiplexed mass analysis
approach--multi Resonant Frequency Excitation (mRFE)
ejection. This new approach divides the mass spectrum into
several mass subranges and detects all the subrange spectra
in parallel for increased mass analysis speed. Mathematical
estimation of standard mass spectrum is demonstrated while
statistical classification on the parallel measurements
remains viable because of the sparse nature of the mass
spectra. This method can reduce mass analysis time by a
factor of 3-6 and increase system duty cycle by 2×. The
combination of reduced analysis time and accurate compound
classification is demonstrated in a commercial quadrupole
ion trap (QIT) system.},
Doi = {10.1007/s13361-014-0894-z},
Key = {fds280148}
}
@article{fds280153,
Author = {Kaganovsky, Y and Li, D and Holmgren, A and Jeon, H and MacCabe, KP and Politte, DG and O'Sullivan, JA and Carin, L and Brady,
DJ},
Title = {Compressed sampling strategies for tomography.},
Journal = {Journal of the Optical Society of America
A},
Volume = {31},
Number = {7},
Pages = {1369-1394},
Year = {2014},
Month = {July},
ISSN = {1084-7529},
url = {http://dx.doi.org/10.1364/josaa.31.001369},
Abstract = {We investigate new sampling strategies for projection
tomography, enabling one to employ fewer measurements than
expected from classical sampling theory without significant
loss of information. Inspired by compressed sensing, our
approach is based on the understanding that many real
objects are compressible in some known representation,
implying that the number of degrees of freedom defining an
object is often much smaller than the number of
pixels/voxels. We propose a new approach based on
quasi-random detector subsampling, whereas previous
approaches only addressed subsampling with respect to source
location (view angle). The performance of different sampling
strategies is considered using object-independent figures of
merit, and also based on reconstructions for specific
objects, with synthetic and real data. The proposed approach
can be implemented using a structured illumination of the
interrogated object or the detector array by placing a coded
aperture/mask at the source or detector side, respectively.
Advantages of the proposed approach include (i) for
structured illumination of the detector array, it leads to
fewer detector pixels and allows one to integrate detectors
for scattered radiation in the unused space; (ii) for
structured illumination of the object, it leads to a reduced
radiation dose for patients in medical scans; (iii) in the
latter case, the blocking of rays reduces scattered
radiation while keeping the same energy in the transmitted
rays, resulting in a higher signal-to-noise ratio than that
achieved by lowering exposure times or the energy of the
source; (iv) compared to view-angle subsampling, it allows
one to use fewer measurements for the same image quality, or
leads to better image quality for the same number of
measurements. The proposed approach can also be combined
with view-angle subsampling.},
Doi = {10.1364/josaa.31.001369},
Key = {fds280153}
}
@article{fds280152,
Author = {Furxhi, O and Marks, DL and Brady, DJ},
Title = {Echelle crossed grating millimeter wave beam
scanner.},
Journal = {Optics Express},
Volume = {22},
Number = {13},
Pages = {16393-16407},
Year = {2014},
Month = {June},
url = {http://dx.doi.org/10.1364/oe.22.016393},
Abstract = {We present a two-dimensional, active, millimeter-wave,
electronic beam scanner, with Doppler capabilities for
stand-off imaging. The two-dimensional scan is achieved by
mapping the millimeter wave spectrum to space using a pair
of crossed gratings. The active transceiver and heterodyne
quadrature detection allow the measurement of the relative
phase between two consecutive measurements and the synthesis
of the scene's Doppler signature. The frame rate of the
imager is currently limited by the sweep rate of the vector
network analyzer which is used to drive the millimeter wave
extenders. All of the beam steering components are passive
and can be designed to operate at any wavelength. The system
design, characterization and measurements are presented and
further uses and improvements are suggested.},
Doi = {10.1364/oe.22.016393},
Key = {fds280152}
}
@article{fds280154,
Author = {Mrozack, A and Heimbeck, M and Marks, DL and Richard, J and Everitt, HO and Brady, DJ},
Title = {Adaptive millimeter-wave synthetic aperture imaging for
compressive sampling of sparse scenes.},
Journal = {Optics Express},
Volume = {22},
Number = {11},
Pages = {13515-13530},
Year = {2014},
Month = {June},
url = {http://dx.doi.org/10.1364/oe.22.013515},
Abstract = {We apply adaptive sensing techniques to the problem of
locating sparse metallic scatterers using high-resolution,
frequency modulated continuous wave W-band RADAR. Using a
single detector, a frequency stepped source, and a lateral
translation stage, inverse synthetic aperture RADAR
reconstruction techniques are used to search for one or two
wire scatterers within a specified range, while an adaptive
algorithm determined successive sampling locations. The
two-dimensional location of each scatterer is thereby
identified with sub-wavelength accuracy in as few as 1/4 the
number of lateral steps required for a simple raster scan.
The implications of applying this approach to more complex
scattering geometries are explored in light of the various
assumptions made.},
Doi = {10.1364/oe.22.013515},
Key = {fds280154}
}
@article{fds280175,
Author = {Marks, DL and Llull, PR and Phillips, Z and Anderson, JG and Feller, SD and Vera, EM and Son, HS and Youn, S-H and Kim, J and Gehm, ME and Brady, DJ and Nichols, JM and Judd, KP and Duncan, MD and Waterman, JR and Stack, RA and Johnson, A and Tennill, R and Olson, CC},
Title = {Characterization of the AWARE 10 two-gigapixel
wide-field-of-view visible imager.},
Journal = {Applied Optics},
Volume = {53},
Number = {13},
Pages = {C54-C63},
Year = {2014},
Month = {May},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/ao.53.000c54},
Abstract = {System requirements for many military electro-optic and IR
camera systems reflect the need for both wide-field-of-view
situational awareness as well as high-resolution imaging for
target identification. In this work we present a new imaging
system architecture designed to perform both functions
simultaneously and the AWARE 10 camera as an example at
visible wavelengths. We first describe the basic system
architecture and user interface followed by a laboratory
characterization of the system optical performance. We then
describe a field experiment in which the camera was used to
identify several maritime targets at varying range. The
experimental results indicate that users of the system are
able to correctly identify ~10 m targets at between 4 and 6
km with 70% accuracy.},
Doi = {10.1364/ao.53.000c54},
Key = {fds280175}
}
@article{fds323401,
Author = {Xie, Y and Tsai, TH and Brady, DJ and Cummer, SA},
Title = {Compressive acoustic imaging with metamaterials.},
Journal = {The Journal of the Acoustical Society of
America},
Volume = {135},
Number = {4},
Pages = {2394},
Year = {2014},
Month = {April},
url = {http://dx.doi.org/10.1121/1.4877922},
Abstract = {Compressive imaging has brought revolutionary design
methodologies to imaging systems. By shuffling and
multiplexing the object information space, the imaging
system compresses data on the physical layer and enables
employing fewer sensors and acquiring less data than
traditional isomorphic mapping imaging systems. Recently
metamaterials have been investigated for designing
compressive imager. Metamaterials are engineered materials
with properties that are usually unattainable in nature.
Acoustic metamaterials can possess highly anisotropy,
strongly dispersion, negative dynamic density, or bulk
modulus, and they open up new possibilities of wave-matter
interaction and signal modulation. In this work, we
designed, fabricated, and tested a metamaterial-based single
detector, 360 degree field of view compressive acoustic
imager. Local resonator arrays are design to resonate
randomly in both spatial and spectrum dimensions to favor
compressive imaging task. The presented experimental results
show that with only about 60 measured values, the imager is
able to reconstruct a scene of more than 1000 sampling
points in space, achieving a compression ratio of about
20:1. Multiple static and moving target imaging task were
performed with this low cost, single detector,
non-mechanical scanning compressive imager. Our work paves
the way for designing metamaterials based compressive
acoustic imaging system.},
Doi = {10.1121/1.4877922},
Key = {fds323401}
}
@article{fds280239,
Author = {Greenberg, JA and Hassan, M and Krishnamurthy, K and Brady,
D},
Title = {Structured illumination for tomographic X-ray diffraction
imaging.},
Journal = {The Analyst},
Volume = {139},
Number = {4},
Pages = {709-713},
Year = {2014},
Month = {February},
ISSN = {0003-2654},
url = {http://dx.doi.org/10.1039/c3an01641b},
Abstract = {Tomographic imaging of the molecular structure of an object
is important for a variety of applications, ranging from
medical and industrial radiography to security screening.
X-ray diffraction imaging is the preeminent technique for
performing molecular analysis of large volumes. Here we
propose and demonstrate a new measurement architecture to
improve the source and detector efficiency for diffraction
imaging. In comparison with previous techniques, our
approach reduces the required overall scan time by 1-2
orders of magnitude, which makes possible real-time scanning
of a broad range of materials over a large volume using a
table-top setup. This method, which relies on structuring
spatially the illumination incident on an object moving
relative to the X-ray source, is compatible with existing
systems and has the potential to significantly enhance
performance in an array of areas, such as medical diagnostic
imaging and explosives detection.},
Doi = {10.1039/c3an01641b},
Key = {fds280239}
}
@article{fds280251,
Author = {Youn, SH and Son, HS and Marks, DL and Shaw, JM and McLaughlin, PO and Feller, SD and Brady, DJ and Kim, J},
Title = {Optical performance test and validation of microcameras in
multiscale, gigapixel imagers.},
Journal = {Optics Express},
Volume = {22},
Number = {3},
Pages = {3712-3723},
Year = {2014},
Month = {February},
url = {http://dx.doi.org/10.1364/oe.22.003712},
Abstract = {Wide field-of-view gigapixel imaging systems capable of
diffraction-limited resolution and video-rate acquisition
have a broad range of applications, including sports event
broadcasting, security surveillance, astronomical
observation, and bioimaging. The complexity of the system
integration of such devices demands precision optical
components that are fully characterized and qualified before
being integrated into the final system. In this work, we
present component and assembly level characterizations of
microcameras in our first gigapixel camera, the AWARE-2.
Based on the results of these measurements, we revised the
optical design and assembly procedures to construct the
second generation system, the AWARE-2 Retrofit, which shows
significant improvement in image quality.},
Doi = {10.1364/oe.22.003712},
Key = {fds280251}
}
@article{fds280146,
Author = {Brady, DJ},
Title = {Roadmap for commercial gigapixel cameras},
Journal = {Optics Infobase Conference Papers},
Year = {2014},
Month = {January},
Abstract = {Multiscale array cameras allow 10-100x improvements in
commercial camera resolution. This talk discussed the
optical manufacturing, electronic processing and
communications and cloud software ecosystem that enables
economical multiscale cameras. © 2014 OSA.},
Key = {fds280146}
}
@article{fds280147,
Author = {Brady, DJ},
Title = {Compressive millimeter wave and X-ray tomography},
Journal = {Optics Infobase Conference Papers},
Year = {2014},
Month = {January},
Abstract = {Compressive tomography consists of estimation of high
dimensional objects from measurements distributed over lower
dimensions. Examples include reconstruction of 3D spectral
data cubes from 2D focal planes and reconstruction of 3D
volumes from 2D x-ray projections or holograms. Compressive
tomographic estimation is improved if projections are
structured to randomize the sampling phase space. To
illustrate this principle, we show that structured x-ray
illumination enables improvements in reconstructed image
quality for compressed measurements relative to full Radon
sampling and that structured millimeter wave illumination
improves estimation of 3D surfaces. © 2014
OSA.},
Key = {fds280147}
}
@article{fds280151,
Author = {Lakshmanan, MN and Kapadia, AJ and Harrawood, BP and Brady, D and Samei,
E},
Title = {X-ray coherent scatter imaging for surgical margin
detection: A Monte Carlo study},
Journal = {Progress in Biomedical Optics and Imaging Proceedings of
Spie},
Volume = {9033},
Publisher = {SPIE},
Year = {2014},
Month = {January},
ISSN = {1605-7422},
url = {http://dx.doi.org/10.1117/12.2043856},
Abstract = {Instead of having the entire breast removed (a mastectomy),
breast cancer patients often receive a breast con-serving
surgery (BCS) for removal of only the breast tumor. If
post-surgery analysis reveals ta missed margin around the
tumor tissue excised through the BCS procedure, the
physician must often call the patient back for another
surgery, which is both difficult and risky for the patient.
If this “margin detectionâ€could be performed
during the BCS procedure itself, the surgical team could use
the analysis to ensure that all tumor tissue was removed in
a single surgery, thereby potentially reducing the number of
call backs from breast cancer surgery. We describe here a
potential technique to detect surgical tumor margins in
breast cancer using x-ray coherent scatter imaging. In this
study, we demonstrate the imaging ability of this technique
using Monte Carlo simulations. © 2014 SPIE.},
Doi = {10.1117/12.2043856},
Key = {fds280151}
}
@article{fds280225,
Author = {Greenberg, JA and Brady, DJ},
Title = {Structured illumination for compressive x-ray diffraction
tomography},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {9020},
Publisher = {SPIE},
Year = {2014},
Month = {January},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.2048264},
Abstract = {Coherent x-ray scatter (also know as x-ray diffraction) has
long been used to non-destructively investigate the
molecular structure of materials for industrial, medical,
security, and fundamental purposes. Unfortunately, molecular
tomography based on coherent scatter typically requires long
scan times and/or large incident fluxes, which has limited
the practical applicability of such schemes. One can
overcome the conventional challenges by employing
compressive sensing theory to optimize the information
obtained per incident photon. We accomplish this in two
primary ways: we use a coded aperture to structure the
incident illumination and realize massive measurement
parallelization and use photon-counting, energy-sensitive
detection to recover maximal information from each detected
photon. We motivate and discuss here the general imaging
principles, investigate different coding and sampling
strategies, and provide results from theoretical studies for
our structured illumination scheme. We find that this
approach promises real-time molecular tomography of bulk
objects without a loss in imaging performance. © 2014
SPIE-IS&T.},
Doi = {10.1117/12.2048264},
Key = {fds280225}
}
@article{fds280228,
Author = {Holmgren, AD and Maccabe, KP and Tornai, MP and Brady,
DJ},
Title = {Coded aperture x-ray scatter tomography},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {9020},
Publisher = {SPIE},
Year = {2014},
Month = {January},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.2048267},
Abstract = {We present a system for X-ray tomography using a coded
aperture. A fan beam illuminates a 2D cross-section of an
object and our coded aperture system produces a tomographic
image from each static snapshot; as such, we can reconstruct
either a static object scanned in 3D or an x-ray video of a
non-static object. © 2014 SPIE-IS&T.},
Doi = {10.1117/12.2048267},
Key = {fds280228}
}
@article{fds280256,
Author = {Greenberg, J and Krishnamurthy, K and Brady, D},
Title = {Compressive single-pixel snapshot x-ray diffraction
imaging.},
Journal = {Optics Letters},
Volume = {39},
Number = {1},
Pages = {111-114},
Publisher = {The Optical Society},
Year = {2014},
Month = {January},
ISSN = {0146-9592},
url = {http://dx.doi.org/10.1364/ol.39.000111},
Abstract = {We present a method for realizing snapshot, depth-resolved
material identification using only a single,
energy-sensitive pixel. To achieve this result, we employ a
coded aperture with subpixel features to modulate the energy
spectrum of coherently scattered photons and recover the
object properties using an iterative inversion algorithm
based on compressed sensing theory. We demonstrate
high-fidelity object estimation at x-ray wavelengths for a
variety of compression ratios exceeding unity.},
Doi = {10.1364/ol.39.000111},
Key = {fds280256}
}
@article{fds280262,
Author = {Arce, GR and Brady, DJ and Carin, L and Arguello, H and Kittle,
DS},
Title = {Compressive coded aperture spectral imaging: An
introduction},
Journal = {Ieee Signal Processing Magazine},
Volume = {31},
Number = {1},
Pages = {105-115},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {1053-5888},
url = {http://dx.doi.org/10.1109/MSP.2013.2278763},
Abstract = {Maging spectroscopy involves the sensing of a large amount
of spatial information across a multitude of wavelengths.
Conventional approaches to hyperspectral sensing scan
adjacent zones of the underlying spectral scene and merge
the results to construct a spectral data cube. Push broom
spectral imaging sensors, for instance, capture a spectral
cube with one focal plane array (FPA) measurement per
spatial line of the scene [1], [2]. Spectrometers based on
optical bandpass filters sequentially scan the scene by
tuning the bandpass filters in steps. The disadvantage of
these techniques is that they require scanning a number of
zones linearly in proportion to the desired spatial and
spectral resolution. This article surveys compressive coded
aperture spectral imagers, also known as coded aperture
snapshot spectral imagers (CASSI) [1], [3], [4], which
naturally embody the principles of compressive sensing (CS)
[5], [6]. The remarkable advantage of CASSI is that the
entire data cube is sensed with just a few FPA measurements
and, in some cases, with as little as a single FPA shot. ©
1991-2012 IEEE.},
Doi = {10.1109/MSP.2013.2278763},
Key = {fds280262}
}
@article{fds280258,
Author = {Greenberg, JA and Krishnamurthy, K and Lakshmanan, M and MacCabe, K and Wolter, S and Kapadia, A and Brady, D},
Title = {Coding and sampling for compressive x-ray diffraction
tomography},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8858},
Publisher = {SPIE},
Year = {2013},
Month = {December},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.2027128},
Abstract = {Coded apertures and energy resolving detectors may be used
to improve the sampling efficiency of x-ray tomography and
increase the physical diversity of x-ray phenomena measured.
Coding and decompressive inference enable increased
molecular specificity, reduced exposure and scan times. We
outline a specific coded aperture x-ray coherent scatter
imaging architecture that demonstrates the potential of such
schemes. Based on this geometry, we develop a physical model
using both a semi-analytic and Monte Carlo-based framework,
devise an experimental realization of the system, describe a
reconstruction algorithm for estimating the object from raw
data, and propose a classification scheme for identifying
the material composition of the object at each location. ©
2013 SPIE.},
Doi = {10.1117/12.2027128},
Key = {fds280258}
}
@article{fds280250,
Author = {Mrozack, A and Krishnamurthy, K and Lipworth, G and Smith, DR and Brady,
DJ},
Title = {Imaging of diffuse objects with dispersive
imagers},
Journal = {International Conference on Infrared, Millimeter, and
Terahertz Waves, Irmmw Thz},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {2162-2027},
url = {http://dx.doi.org/10.1109/IRMMW-THz.2013.6665888},
Abstract = {Dispersive imagers measure multiple speckle realizations of
the object to be estimated. This poses a challenge for
coherent imaging as classically objects are backpropagated
and then despeckled. We present initial findings on an
intensity based method for estimating the scattering
density. © 2013 IEEE.},
Doi = {10.1109/IRMMW-THz.2013.6665888},
Key = {fds280250}
}
@article{fds280264,
Author = {Nakamura, T and Kittle, DS and Youn, SH and Feller, SD and Tanida, J and Brady, DJ},
Title = {Autofocus for a multiscale gigapixel camera.},
Journal = {Applied Optics},
Volume = {52},
Number = {33},
Pages = {8146-8153},
Year = {2013},
Month = {November},
ISSN = {1559-128X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000327467200039&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {In recent studies, the advanced wide field of view
architectures for image reconstruction and exploitation
(AWARE) multiscale camera, which is composed of a
monocentric objective lens and an array of microcameras, was
developed for the realization of snapshot wide field of view
and high resolution imaging. This paper describes
accelerated autofocus (AF) methods for the AWARE system
based on a hierarchical spatial algorithm and an iterative
temporal algorithm. In the algorithms, sensor positions of
each microcamera are hierarchically scanned with contrast
detection to effectively search for a focusing distance. The
positions are then updated iteratively for dynamic scenes
using temporal information. The algorithms are theoretically
analyzed and experimentally demonstrated. The developed AF
methods can be used for the realization of the temporal
gigapixel imaging by the AWARE system.},
Doi = {10.1364/ao.52.008146},
Key = {fds280264}
}
@article{fds280265,
Author = {Son, HS and Marks, DL and Hahn, J and Kim, J and Brady,
DJ},
Title = {Design of a spherical focal surface using close-packed relay
optics: erratum.},
Journal = {Optics Express},
Volume = {21},
Number = {22},
Pages = {27284-27285},
Year = {2013},
Month = {November},
url = {http://dx.doi.org/10.1364/oe.21.027284},
Abstract = {A coding error was found in calculating the optimal packing
distribution of our geodesic array. The error was corrected
and the new optimization results in slightly improved
packing density. The overall approach and algorithm remain
unchanged.},
Doi = {10.1364/oe.21.027284},
Key = {fds280265}
}
@article{fds280266,
Author = {Brady, DJ and Marks, DL and MacCabe, KP and O'Sullivan,
JA},
Title = {Coded apertures for x-ray scatter imaging.},
Journal = {Applied Optics},
Volume = {52},
Number = {32},
Pages = {7745-7754},
Year = {2013},
Month = {November},
ISSN = {1559-128X},
url = {http://dx.doi.org/10.1364/ao.52.007745},
Abstract = {We examine coding strategies for coded aperture scatter
imagers. Scatter imaging enables tomography of compact
regions from snapshot measurements. We present coded
aperture designs for pencil and fan beam geometries, and
compare their singular value spectra with that of the Radon
transform and selected volume tomography. We show that under
dose constraints scatter imaging improves conditioning over
alternative techniques, and that specially designed coded
apertures enable snapshot 1D and 2D tomography.},
Doi = {10.1364/ao.52.007745},
Key = {fds280266}
}
@article{fds280259,
Author = {Greenberg, JA and Krishnamurthy, K and Brady, D},
Title = {Snapshot molecular imaging using coded energy-sensitive
detection.},
Journal = {Optics Express},
Volume = {21},
Number = {21},
Pages = {25480-25491},
Year = {2013},
Month = {October},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.21.025480},
Abstract = {We demonstrate a technique for measuring the range-resolved
coherent scatter form factors of different objects from a
single snapshot. By illuminating the object with an x-ray
pencil beam and placing a coded aperture in front of a
linear array of energy-sensitive detector elements, we
record the coherently scattered x-rays. This approach yields
lateral, range, and momentum transfer resolutions of 1 mm, 5
mm, and 0.2 nm⁻¹, respectively, which is sufficient for
the distinguishing a variety of solids and liquids. These
results indicate a path toward real-time volumetric
molecular imaging for non-destructive examination in a
variety of applications, including medical diagnostics,
quality inspection, and security detection.},
Doi = {10.1364/oe.21.025480},
Key = {fds280259}
}
@article{fds280273,
Author = {Lipworth, G and Mrozack, A and Hunt, J and Marks, DL and Driscoll, T and Brady, D and Smith, DR},
Title = {Metamaterial apertures for coherent computational imaging on
the physical layer.},
Journal = {Journal of the Optical Society of America
A},
Volume = {30},
Number = {8},
Pages = {1603-1612},
Year = {2013},
Month = {August},
ISSN = {1084-7529},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000322591800017&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {We introduce the concept of a metamaterial aperture, in
which an underlying reference mode interacts with a designed
metamaterial surface to produce a series of complex field
patterns. The resonant frequencies of the metamaterial
elements are randomly distributed over a large bandwidth
(18-26 GHz), such that the aperture produces a rapidly
varying sequence of field patterns as a function of the
input frequency. As the frequency of operation is scanned,
different subsets of metamaterial elements become active, in
turn varying the field patterns at the scene. Scene
information can thus be indexed by frequency, with the
overall effectiveness of the imaging scheme tied to the
diversity of the generated field patterns. As the quality
(Q-) factor of the metamaterial resonators increases, the
number of distinct field patterns that can be generated
increases-improving scene estimation. In this work we
provide the foundation for computational imaging with
metamaterial apertures based on frequency diversity, and
establish that for resonators with physically relevant
Q-factors, there are potentially enough distinct
measurements of a typical scene within a reasonable
bandwidth to achieve diffraction-limited reconstructions of
physical scenes.},
Doi = {10.1364/josaa.30.001603},
Key = {fds280273}
}
@article{fds280275,
Author = {Rajwade, A and Kittle, D and Tsai, TH and Brady, D and Carin,
L},
Title = {Coded hyperspectral imaging and blind compressive
sensing},
Journal = {Siam Journal on Imaging Sciences},
Volume = {6},
Number = {2},
Pages = {782-812},
Publisher = {Society for Industrial & Applied Mathematics
(SIAM)},
Year = {2013},
Month = {July},
ISSN = {1936-4954},
url = {http://dx.doi.org/10.1137/120875302},
Abstract = {Blind compressive sensing (CS) is considered for
reconstruction of hyperspectral data imaged by a coded
aperture camera. The measurements are manifested as a
superposition of the coded wavelength-dependent data, with
the ambient three-dimensional hyperspectral datacube mapped
to a two-dimensional measurement. The hyperspectral datacube
is recovered using a Bayesian implementation of blind CS.
Several demonstration experiments are presented, including
measurements performed using a coded aperture snapshot
spectral imager (CASSI) camera. The proposed approach is
capable of efficiently reconstructing large hyperspectral
datacubes. Comparisons are made between the proposed
algorithm and other techniques employed in compressive
sensing, dictionary learning, and matrix factorization. ©
2013 Society for Industrial and Applied Mathematics.},
Doi = {10.1137/120875302},
Key = {fds280275}
}
@article{fds280277,
Author = {MacCabe, KP and Holmgren, AD and Tornai, MP and Brady,
DJ},
Title = {Snapshot 2D tomography via coded aperture x-ray scatter
imaging.},
Journal = {Appl Opt},
Volume = {52},
Number = {19},
Pages = {4582-4589},
Year = {2013},
Month = {July},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23842254},
Abstract = {This paper describes a fan beam coded aperture x-ray scatter
imaging system that acquires a tomographic image from each
snapshot. This technique exploits the cylindrical symmetry
of the scattering cross section to avoid the scanning motion
typically required by projection tomography. We use a coded
aperture with a harmonic dependence to determine range and a
shift code to determine cross range. Here we use a
forward-scatter configuration to image 2D objects and use
serial exposures to acquire tomographic video of motion
within a plane. Our reconstruction algorithm also estimates
the angular dependence of the scattered radiance, a step
toward materials imaging and identification.},
Doi = {10.1364/AO.52.004582},
Key = {fds280277}
}
@article{fds280278,
Author = {Kapadia, AJ and Lakshmanan, MN and Krishnamurthy, K and Sahbaee, P and Chawla, A and Wolter, S and Maccabe, K and Brady, D and Samei,
E},
Title = {Monte-Carlo simulations of a coded-aperture X-ray scatter
imaging system for molecular imaging},
Journal = {Progress in Biomedical Optics and Imaging Proceedings of
Spie},
Volume = {8668},
Publisher = {SPIE},
Year = {2013},
Month = {June},
ISSN = {1605-7422},
url = {http://dx.doi.org/10.1117/12.2008484},
Abstract = {In this work, we demonstrate the ability to determine the
material composition of a sample by measuring coherent
scatter diffraction patterns generated using a
coded-aperture x-ray scatter imaging (CAXSI) system. Most
materials are known to exhibit unique diffraction patterns
through coherent scattering of low-energy x-rays. However,
clinical x-ray imagers typically discard scatter radiation
as noise that degrades image quality. Through the addition
of a coded aperture, the system can be sensitized to
coherent scattered photons that carry information about the
identity and location of the scattering material. In this
work, we demonstrate this process using a Monte-Carlo
simulation of a CAXSI system. A simulation of a CAXSI system
was developed in GEANT4 with modified physics libraries to
model coherent scatter diffraction patterns in materials.
Simulated images were generated from 10 materials including
plastics, hydrocarbons, and biological tissue. The materials
were irradiated using collimated pencil- and fan-beams with
energies of 160 kVp. The diffraction patterns were imaged
using a simulated 2D detector and mathematically
deconstructed using an analytical projection model that
accounted for the known x-ray source spectrum. The
deconstructed diffraction patterns were then matched with a
library of known coherent scatter form-factors of different
materials to determine the identity of the scatterer at
different locations in the object. The results showed good
agreement between the measured and known scatter patterns
from the materials, demonstrating the ability to image and
identify materials at different 3D locations within an
object using a projection-based CAXSI system. © 2013
SPIE.},
Doi = {10.1117/12.2008484},
Key = {fds280278}
}
@article{fds280276,
Author = {Marks, DL and Hagen, N and Durham, M and Brady, DJ},
Title = {Wide-field compact catadioptric telescope spanning 0.7-14
μm wavelengths.},
Journal = {Applied Optics},
Volume = {52},
Number = {18},
Pages = {4334-4342},
Year = {2013},
Month = {June},
ISSN = {1559-128X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000320708500031&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {We present a wide-field compact f-1.2, f-1.6 effective
illumination catadioptric telescope that spans the
wavelengths 0.7-14.0 μm. Such a telescope replaces several
telescopes designed for different infrared bands, while
having a track length shorter than most single-band
telescopes. Incorporated with a suitable multiband focal
plane array, many wavelength bands may be imaged
simultaneously in the same instrument. We have constructed
and tested prototypes of the telescopes and found the
performance is near the predicted values.},
Doi = {10.1364/ao.52.004334},
Key = {fds280276}
}
@article{fds280280,
Author = {Kittle, DS and Marks, DL and Son, HS and Kim, J and Brady,
DJ},
Title = {A testbed for wide-field, high-resolution, gigapixel-class
cameras.},
Journal = {Rev Sci Instrum},
Volume = {84},
Number = {5},
Pages = {053107},
Year = {2013},
Month = {May},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23742532},
Abstract = {The high resolution and wide field of view (FOV) of the
AWARE (Advanced Wide FOV Architectures for Image
Reconstruction and Exploitation) gigapixel class cameras
present new challenges in calibration, mechanical testing,
and optical performance evaluation. The AWARE system
integrates an array of micro-cameras in a multiscale design
to achieve gigapixel sampling at video rates. Alignment and
optical testing of the micro-cameras is vital in compositing
engines, which require pixel-level accurate mappings over
the entire array of cameras. A testbed has been developed to
automatically calibrate and measure the optical performance
of the entire camera array. This testbed utilizes
translation and rotation stages to project a ray into any
micro-camera of the AWARE system. A spatial light modulator
is projected through a telescope to form an arbitrary object
space pattern at infinity. This collimated source is then
reflected by an elevation stage mirror for pointing through
the aperture of the objective into the micro-optics and
eventually the detector of the micro-camera. Different
targets can be projected with the spatial light modulator
for measuring the modulation transfer function (MTF) of the
system, fiducials in the overlap regions for registration
and compositing, distortion mapping, illumination profiles,
thermal stability, and focus calibration. The mathematics of
the testbed mechanics are derived for finding the positions
of the stages to achieve a particular incident angle into
the camera, along with calibration steps for alignment of
the camera and testbed coordinate axes. Measurement results
for the AWARE-2 gigapixel camera are presented for MTF,
focus calibration, illumination profile, fiducial mapping
across the micro-camera for registration and distortion
correction, thermal stability, and alignment of the camera
on the testbed.},
Doi = {10.1063/1.4804199},
Key = {fds280280}
}
@article{fds280283,
Author = {Marks, DL and Brady, DJ},
Title = {Wide-field astronomical multiscale cameras},
Journal = {The Astronomical Journal},
Volume = {145},
Number = {5},
Pages = {128-128},
Publisher = {IOP Publishing},
Year = {2013},
Month = {May},
ISSN = {0004-6256},
url = {http://dx.doi.org/10.1088/0004-6256/145/5/128},
Abstract = {In order to produce sufficiently low aberrations with a
large aperture, telescopes have a limited field of view.
Because of this narrow field, large areas of the sky at a
given time are unobserved. We propose several telescopes
based on monocentric reflective, catadioptric, and
refractive objectives that may be scaled to wide fields of
view and achieve 1.″1 resolution, which in most locations
is the practical seeing limit of the atmosphere. The
reflective and Schmidt catadioptric objectives have
relatively simple configurations and enable large fields to
be captured at the expense of the obscuration of the mirror
by secondary optics, a defect that may be managed by image
plane design. The refractive telescope design does not have
an obscuration but the objective has substantial bulk. The
refractive design is a 38 gigapixel camera which consists of
a single monocentric objective and 4272 microcameras.
Monocentric multiscale telescopes, with their wide fields of
view, may observe phenomena that might otherwise be
unnoticed, such as supernovae, glint from orbital space
debris, and near-earth objects. © 2013. The American
Astronomical Society. All rights reserved.},
Doi = {10.1088/0004-6256/145/5/128},
Key = {fds280283}
}
@article{fds304126,
Author = {Llull, P and Liao, X and Yuan, X and Yang, J and Kittle, D and Carin, L and Sapiro, G and Brady, DJ},
Title = {Coded aperture compressive temporal imaging.},
Journal = {Optics Express},
Volume = {21},
Number = {9},
Pages = {10526-10545},
Year = {2013},
Month = {May},
url = {http://arxiv.org/abs/1302.2575v1},
Abstract = {We use mechanical translation of a coded aperture for code
division multiple access compression of video. We discuss
the compressed video's temporal resolution and present
experimental results for reconstructions of > 10 frames of
temporal data per coded snapshot.},
Doi = {10.1364/oe.21.010526},
Key = {fds304126}
}
@article{fds280282,
Author = {Kittle, DS and Marks, DL and Brady, DJ},
Title = {Automated calibration and optical testing of the AWARE-2
gigapixel multiscale camera},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8660},
Publisher = {SPIE},
Year = {2013},
Month = {April},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.2008836},
Abstract = {Gigapixel-class cameras present new challenges in
calibration, mechanical testing, and optical performance
evaluation. The AWARE-2 gigapixel camera has nearly
one-hundred micro-cameras covering a 120 degree wide by 40
degree tall field of view, with one pixel spanning an 8
arcsec field angle. Viewing the imagery requires stitching
the sub-images together by applying an accurate mapping of
registration parameters over the entire field of view. For
this purpose, a testbed has been developed to automatically
calibrate and test each micro-camera in the array. Using
translation stages, rotation stages, and a spatial light
modulator for object space, this testbed can project any
test scene into a specified micro-camera, building up image
quality metrics and a registration look-up table over the
entire array. © 2013 SPIE-IS&T.},
Doi = {10.1117/12.2008836},
Key = {fds280282}
}
@article{fds280281,
Author = {Brady, DJ and Marks, DL and Feller, S and Gehm, M and Golish, D and Vera,
E and Kittle, D},
Title = {Petapixel photography and the limits of camera information
capacity},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8657},
Publisher = {SPIE},
Year = {2013},
Month = {April},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.2014274},
Abstract = {The monochromatic single frame pixel count of a camera is
limited by diffraction to the space-bandwidth product,
roughly the aperture area divided by the square of the
wavelength. We have recently shown that it is possible to
approach this limit using multiscale lenses for cameras with
space bandwidth product between 1 and 100 gigapixels. When
color, polarization, coherence and time are included in the
image data cube, camera information capacity may exceed 1
petapixel/second. This talk reviews progress in the
construction of DARPA AWARE gigapixel cameras and describes
compressive measurement strategies that may be used in
combination with multiscale systems to push camera capacity
to near physical limits. © 2013 SPIE-IS&T.},
Doi = {10.1117/12.2014274},
Key = {fds280281}
}
@article{fds280284,
Author = {Tsai, T-H and Brady, DJ},
Title = {Coded aperture snapshot spectral polarization
imaging.},
Journal = {Applied Optics},
Volume = {52},
Number = {10},
Pages = {2153-2161},
Year = {2013},
Month = {April},
ISSN = {1559-128X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000316988100032&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {We describe a single-shot polarization spectral imager that
combines two birefringent crystals with a binary coded
aperture to encode the spatial, spectral and polarization
data cube for compressive sampling on a two-dimensional (2D)
detector array. We use a total variation prior to
reconstruct the four-dimensional (4D) data cube from the
single 2D measurement. The 4D data cube includes 1500×1240
pixels in the spatial domain, 19 wavelength channels between
400 and 680 nm and two Stokes parameters.},
Doi = {10.1364/ao.52.002153},
Key = {fds280284}
}
@article{fds280287,
Author = {Son, HS and Johnson, A and Stack, RA and Shaw, JM and McLaughlin, P and Marks, DL and Brady, DJ and Kim, J},
Title = {Optomechanical design of multiscale gigapixel digital
camera.},
Journal = {Applied Optics},
Volume = {52},
Number = {8},
Pages = {1541-1549},
Year = {2013},
Month = {March},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23478755},
Abstract = {Recent developments in multiscale imaging systems have
opened up the possibility for commercially viable wide-field
gigapixel cameras. While multiscale design principles allow
tremendous simplification of the optical design, they place
increased emphasis on optomechanics and system level
integration of the camera as a whole. In this paper we
present the optomechanical design of a prototype
two-gigapixel system (AWARE-2) that has been constructed and
tested.},
Doi = {10.1364/ao.52.001541},
Key = {fds280287}
}
@article{fds280161,
Author = {Krishnamurthy, K and Mrozack, A and Maggioni, M and Brady,
D},
Title = {Multiscale, dictionary-based speckle denoising},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
Abstract = {We propose a multiscale, dictionary-based, data-adaptive
estimation method to recover intensities from
multiplicative, speckle data. The proposed method preserves
the edges and textures in the underlying image while
smoothing intensities in homogenous regions. © OSA
2013.},
Key = {fds280161}
}
@article{fds280163,
Author = {Vera, E and Golish, D and Gong, Q and Kittle, D and Feller, S and Brady, D and Gehm, M},
Title = {Efficient model-based tonemapping of high dynamic range
gigapixel images},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
Abstract = {We present a technique to address the tonemapping of high
dynamic range (HDR) gigapixel images. The proposed method
relies on extracting low-dimensional models from
lowresolution proxy images, and can be efficiently
implemented in a parallel manner. © OSA
2013.},
Key = {fds280163}
}
@article{fds280164,
Author = {Vera, E and Golish, D and Gong, Q and Kelly, K and Kittle, D and Feller, S and Brady, D and Gehm, M},
Title = {Color image formation for multiscale gigapixel
imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
Abstract = {We present the current development of the image formation
pipeline for color gigapixel images obtained by the AWARE-10
multiscale camera.We introduce a camera simulator, the
modifications to the scalable pipeline, and the challenges
for creating seamless color gigapixel panoramas. © 2013
Optical Society of America.},
Key = {fds280164}
}
@article{fds280202,
Author = {Zhu, R and Tsai, TH and Brady, DJ},
Title = {Coded aperture snapshot spectral imager based on liquid
crystal spatial light modulator},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
Abstract = {We describe the use of a liquid crystal on silicon modulator
to jointly code spatial and spectral features for snapshot
spectral imaging. We demonstrate compressive measurement of
megapixel multispectral image with 5 nm resolution. © OSA
2013.},
Key = {fds280202}
}
@article{fds280204,
Author = {MacCabe, KP and Holmgren, AD and Greenberg, JA and Brady,
DJ},
Title = {Coding for X-ray scatter imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
Abstract = {We present coding strategies for x-ray scatter imaging, with
focus on pencil and fan beam geometries. Coded apertures
spatially modulate the scatter signal prior to measurement,
and appropriate reconstruction algorithms recover the
tomographic images. © OSA 2013.},
Key = {fds280204}
}
@article{fds280219,
Author = {Marks, DL and Brady, DJ},
Title = {A wide-field catadioptric monocentric multiscale telescope
with all-spherical glass optics},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
Abstract = {Monocentric multiscale design combines a common objective
optic with an array of secondary apertures to enable wide
field of view high resolution imaging. Here we describe a
15o field of view with 1.1 arcsecond ifov. © OSA
2013.},
Key = {fds280219}
}
@article{fds280220,
Author = {Marks, DL and Brady, DJ},
Title = {Optical design for computational imaging instruments
(invited paper)},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
Abstract = {Using electronic sensors and computation, optical
instruments that acquire images solely for algorithmic
interpretation are increasingly frequent. High depth of
focus, high resolution, and wide fields are simultaneously
achieved with joint optical and computational designs. ©
OSA 2013.},
Key = {fds280220}
}
@article{fds280221,
Author = {Llull, P and Liao, X and Yuan, X and Yang, J and Kittle, D and Carin, L and Sapiro, G and Brady, DJ},
Title = {Compressive sensing for video using a passive coding
element},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
Abstract = {We present a prototype system that utilizes mechanical
translation of a passive coding element to compress
high-speed temporal information into low-framerate video
sequences. Reconstructions of 148 frames per experimental
coded snapshot are reported. © OSA 2013.},
Key = {fds280221}
}
@article{fds280222,
Author = {Mrozack, A and Heimbeck, M and Marks, DL and Richard, J and Everitt, HO and Brady, DJ},
Title = {Adaptive scanning for synthetic aperture
imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2013},
Month = {January},
Abstract = {Synthetic aperture imagers measure the space-bandwidth
product of full-apertures by moving a single detector. We
show results from an adaptive sensing experiment that
demonstrate a three times speedup over full-scans. © 2013
Optical Society of America.},
Key = {fds280222}
}
@article{fds280226,
Author = {Yuan, X and Yang, J and Llull, P and Liao, X and Sapiro, G and Brady, DJ and Carin, L},
Title = {Adaptive temporal compressive sensing for
video},
Journal = {2013 Ieee International Conference on Image Processing, Icip
2013 Proceedings},
Pages = {14-18},
Year = {2013},
Month = {January},
url = {http://hdl.handle.net/10161/8941 Duke open
access},
Abstract = {This paper introduces the concept of adaptive temporal
compressive sensing (CS) for video. We propose a CS
algorithm to adapt the compression ratio based on the
scene's temporal complexity, computed from the compressed
data, without compromising the quality of the reconstructed
video. The temporal adaptivity is manifested by manipulating
the integration time of the camera, opening the possibility
to realtime implementation. The proposed algorithm is a
generalized temporal CS approach that can be incorporated
with a diverse set of existing hardware systems. © 2013
IEEE.},
Doi = {10.1109/ICIP.2013.6738004},
Key = {fds280226}
}
@article{fds280227,
Author = {Yang, J and Yuan, X and Liao, X and Llull, P and Sapiro, G and Brady, DJ and Carin, L},
Title = {Gaussian mixture model for video compressive
sensing},
Journal = {2013 Ieee International Conference on Image Processing, Icip
2013 Proceedings},
Pages = {19-23},
Publisher = {IEEE},
Year = {2013},
Month = {January},
url = {http://dx.doi.org/10.1109/ICIP.2013.6738005},
Abstract = {A Gaussian Mixture Model (GMM)-based algorithm is proposed
for video reconstruction from temporal compressed
measurements. The GMM is used to model spatio-temporal video
patches, and the reconstruction can be efficiently computed
based on analytic expressions. The developed GMM
reconstruction method benefits from online adaptive learning
and parallel computation. We demonstrate the efficacy of the
proposed GMM with videos reconstructed from simulated
compressive video measurements and from a real compressive
video camera. © 2013 IEEE.},
Doi = {10.1109/ICIP.2013.6738005},
Key = {fds280227}
}
@article{fds280237,
Author = {Iliopoulos, AS and Hu, J and Pitsianis, N and Sun, X and Gehm, M and Brady,
D},
Title = {Big snapshot stitching with scarce overlap},
Journal = {2013 Ieee High Performance Extreme Computing Conference,
Hpec 2013},
Publisher = {IEEE},
Year = {2013},
Month = {January},
url = {http://dx.doi.org/10.1109/HPEC.2013.6670349},
Abstract = {We address certain properties that arise in gigapixel-scale
image stitching for snapshot images captured with a novel
micro-camera array system, AWARE-2. This system features a
greatly extended field of view and high optical resolution,
offering unique sensing capabilities for a host of important
applications. However, three simultaneously arising
conditions pose a challenge to existing approaches to image
stitching, with regard to the quality of the output image as
well as the automation and efficiency of the image
composition process. Put simply, they may be described as
the sparse, geometrically irregular, and noisy (S.I.N.)
overlap amongst the fields of view of the constituent
micro-cameras. We introduce a computational pipeline for
image stitching under these conditions, which is scalable in
terms of complexity and efficiency. With it, we also
substantially reduce or eliminate ghosting effects due to
misalignment factors, without entailing manual intervention.
Our present implementation of the pipeline leverages the
combined use of multicore and GPU architectures. We present
experimental results with the pipeline on real image data
acquired with AWARE-2. © 2013 IEEE.},
Doi = {10.1109/HPEC.2013.6670349},
Key = {fds280237}
}
@article{fds280286,
Author = {Hunt, J and Driscoll, T and Mrozack, A and Lipworth, G and Reynolds, M and Brady, D and Smith, DR},
Title = {Metamaterial apertures for computational
imaging.},
Journal = {Science (New York, N.Y.)},
Volume = {339},
Number = {6117},
Pages = {310-313},
Year = {2013},
Month = {January},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23329043},
Abstract = {By leveraging metamaterials and compressive imaging, a
low-profile aperture capable of microwave imaging without
lenses, moving parts, or phase shifters is demonstrated.
This designer aperture allows image compression to be
performed on the physical hardware layer rather than in the
postprocessing stage, thus averting the detector, storage,
and transmission costs associated with full
diffraction-limited sampling of a scene. A guided-wave
metamaterial aperture is used to perform compressive image
reconstruction at 10 frames per second of two-dimensional
(range and angle) sparse still and video scenes at K-band
(18 to 26 gigahertz) frequencies, using frequency diversity
to avoid mechanical scanning. Image acquisition is
accomplished with a 40:1 compression ratio.},
Doi = {10.1126/science.1230054},
Key = {fds280286}
}
@article{fds280388,
Author = {Chen, S and Li, P and Brady, D and Lehman, B},
Title = {Determining the optimum grid-connected photovoltaic inverter
size},
Journal = {Solar Energy},
Volume = {87},
Number = {1},
Pages = {96-116},
Publisher = {Elsevier BV},
Year = {2013},
Month = {January},
ISSN = {0038-092X},
url = {http://dx.doi.org/10.1016/j.solener.2012.09.012},
Abstract = {This paper discusses the practical factors that may
influence the inverter sizing strategy. Effects of various
factors are studied separately by isolating parameters in
the simulations. These factors include irradiance and
temperature conditions of the photovoltaic (PV) installation
location, PV incentives, electricity rates, and inverter
intrinsic parameters such as overload protection schemes and
efficiency curves. Specifically, examples of nine different
geographic locations in the US are simulated and discussed
with realistic parameters to show that the optimum inverter
size varies notably by location and context. © 2012
Elsevier Ltd.},
Doi = {10.1016/j.solener.2012.09.012},
Key = {fds280388}
}
@article{fds280271,
Author = {Son, HS and Marks, DL and Brady, DJ and Kim, J},
Title = {Oversampled triangulation of AWARE-10 monocentric ball lens
using an auto-stigmatic microscope},
Journal = {Optics Express},
Volume = {21},
Number = {19},
Pages = {22206-22214},
Year = {2013},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/OE.21.022206},
Abstract = {In our development of multiscale, gigapixel camera
architectures, there is a need for an accurate
three-dimensional position alignment of large monocentric
lenses relative to hemispherical dome structures. In this
work we describe a method for estimating the position of the
objective lens in our AWARE-10 four-gigapixel camera using
the retro-reflected signal of a custom-designed
auto-stigmatic microscope. We show that although the
physical constraints of the system limit the numerical
aperture of the microscope probe beam to around 0.016, which
results in poor sensitivity in the axial direction, the
lateral sensitivity is more than sufficient to verify that
the position of the objective is within optical tolerances.
© 2013 Optical Society of America.},
Doi = {10.1364/OE.21.022206},
Key = {fds280271}
}
@article{fds280274,
Author = {Youn, SH and Marks, DL and McLaughlin, PO and Brady, DJ and Kim,
J},
Title = {Efficient testing methodologies for microcameras in a
gigapixel imaging system},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8788},
Publisher = {SPIE},
Year = {2013},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.2020739},
Abstract = {Multiscale parallel imaging - based on a monocentric optical
design - promises revolutionary advances in diverse imaging
applications by enabling high resolution, real-time image
capture over a wide field-of-view (FOV), including sport
broadcast, wide-field microscopy, astronomy, and security
surveillance. Recently demonstrated AWARE-2 is a gigapixel
camera consisting of an objective lens and 98 microcameras
spherically arranged to capture an image over FOV of 120 by
50, using computational image processing to form a composite
image of 0.96 gigapixels. Since microcameras are capable of
individually adjusting exposure, gain, and focus, true
parallel imaging is achieved with a high dynamic range. From
the integration perspective, manufacturing and verifying
consistent quality of microcameras is a key to successful
realization of AWARE cameras. We have developed an efficient
testing methodology that utilizes a precisely fabricated dot
grid chart as a calibration target to extract critical
optical properties such as optical distortion, veiling glare
index, and modulation transfer function to validate imaging
performance of microcameras. This approach utilizes an AWARE
objective lens simulator which mimics the actual objective
lens but operates with a short object distance, suitable for
a laboratory environment. Here we describe the principles of
the methodologies developed for AWARE microcameras and
discuss the experimental results with our prototype
microcameras. Reference Brady, D. J., Gehm, M. E., Stack, R.
A., Marks, D. L., Kittle, D. S., Golish, D. R., Vera, E. M.,
and Feller, S. D., "Multiscale gigapixel photography,"
Nature 486, 386 - 389 (2012). © 2013 SPIE.},
Doi = {10.1117/12.2020739},
Key = {fds280274}
}
@article{fds280279,
Author = {Marks, DL and Youn, SH and Son, HS and Kim, J and Brady,
DJ},
Title = {Wide-field microscopy using microcamera arrays},
Journal = {Progress in Biomedical Optics and Imaging Proceedings of
Spie},
Volume = {8589},
Publisher = {SPIE},
Year = {2013},
ISSN = {1605-7422},
url = {http://dx.doi.org/10.1117/12.2002860},
Abstract = {A microcamera is a relay lens paired with image sensors.
Microcameras are grouped into arrays to relay overlapping
views of a single large surface to the sensors to form a
continuous synthetic image. The imaged surface may be curved
or irregular as each camera may independently be dynamically
focused to a different depth. Microcamera arrays are akin to
microprocessors in supercomputers in that both join
individual processors by an optoelectronic routing fabric to
increase capacity and performance. A microcamera may image
ten or more megapixels and grouped into an array of several
hundred, as has already been demonstrated by the DARPA AWARE
Wide-Field program with multiscale gigapixel photography. We
adapt gigapixel microcamera array architectures to
wide-field microscopy of irregularly shaped surfaces to
greatly increase area imaging over 1000 square millimeters
at resolutions of 3 microns or better in a single snapshot.
The system includes a novel relay design, a sensor
electronics package, and a FPGA-based networking fabric.
Biomedical applications of this include screening for skin
lesions, wide-field and resolution-agile microsurgical
imaging, and microscopic cytometry of millions of cells
performed in situ. © 2013 Copyright SPIE.},
Doi = {10.1117/12.2002860},
Key = {fds280279}
}
@article{fds280249,
Author = {Marks, DL and Son, HS and McLaughlin, PO and Feller, SD and Kim, J and Brady, DJ},
Title = {A common scalable microcamera design for 2, 10, and 40
gigapixel class multiscale cameras},
Journal = {Frontiers in Optics, Fio 2012},
Year = {2012},
Month = {December},
Abstract = {Gigapixel camera economics favors reutilization of design
components including optics, optomechanics, and electronics.
We show microcamera designs for multiscale architectures
that only change optical surface profiles that span orders
of magnitude of gigapixels. © OSA 2012.},
Key = {fds280249}
}
@article{fds280400,
Author = {Yue, T and Hao, Q and Brady, DJ},
Title = {Distributed binary geometric sensor arrays for
low-data-throughput human gait biometrics},
Journal = {Proceedings of the Ieee Sensor Array and Multichannel Signal
Processing Workshop},
Pages = {457-460},
Publisher = {IEEE},
Year = {2012},
Month = {October},
ISSN = {2151-870X},
url = {http://dx.doi.org/10.1109/SAM.2012.6250537},
Abstract = {We present a novel sensing paradigm of measuring human gait.
The goal of the research is to achieve low-cost gait
biometrics systems with minimum data throughput for various
sensing modalities. The binary measurements of the system
are achieved by using both (1) periodic and (2)
pseudo-random sampling structures. As a result, either
static or dynamic gait features can be estimated from a
one-bit data stream. The simulation results demonstrate the
gait information acquisition capability of the proposed
binary sensing technology. © 2012 IEEE.},
Doi = {10.1109/SAM.2012.6250537},
Key = {fds280400}
}
@article{fds280385,
Author = {Golish, DR and Vera, EM and Kelly, KJ and Gong, Q and Jansen, PA and Hughes, JM and Kittle, DS and Brady, DJ and Gehm,
ME},
Title = {Development of a scalable image formation pipeline for
multiscale gigapixel photography.},
Journal = {Optics Express},
Volume = {20},
Number = {20},
Pages = {22048-22062},
Year = {2012},
Month = {September},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.20.022048},
Abstract = {We report on the image formation pipeline developed to
efficiently form gigapixel-scale imagery generated by the
AWARE-2 multiscale camera. The AWARE-2 camera consists of 98
"microcameras" imaging through a shared spherical objective,
covering a 120° x 50° field of view with approximately 40
microradian instantaneous field of view (the angular extent
of a pixel). The pipeline is scalable, capable of producing
imagery ranging in scope from "live" one megapixel views to
full resolution gigapixel images. Architectural choices that
enable trivially parallelizable algorithms for rapid image
formation and on-the-fly microcamera alignment compensation
are discussed.},
Doi = {10.1364/oe.20.022048},
Key = {fds280385}
}
@article{fds280386,
Author = {MacCabe, K and Krishnamurthy, K and Chawla, A and Marks, D and Samei, E and Brady, D},
Title = {Pencil beam coded aperture x-ray scatter
imaging},
Journal = {Optics Express},
Volume = {20},
Number = {15},
Pages = {16310-16320},
Year = {2012},
Month = {July},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/OE.20.016310},
Abstract = {We use coded aperture x-ray scatter imaging to interrogate
scattering targets with a pencil beam. Observations from a
single x-ray exposure of a flat-panel scintillation detector
are used to simultaneously determine the along-beam
positions and momentum transfer profiles of two crystalline
powders (NaCl and Al). The system operates with a 3 cm range
resolution and a momentum transfer resolution of 0.1 nm 1.
These results demonstrate that a single snapshot can be used
to estimate scattering properties along an x-ray beam, and
serve as a foundation for volumetric imaging of scattering
objects. © 2012 Optical Society of America.},
Doi = {10.1364/OE.20.016310},
Key = {fds280386}
}
@article{fds280288,
Author = {Brady, DJ and Gibbons, R},
Title = {Computational imaging},
Journal = {Optical Engineering},
Volume = {51},
Number = {7},
Pages = {071401-071401},
Publisher = {SPIE-Intl Soc Optical Eng},
Year = {2012},
Month = {July},
ISSN = {0091-3286},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000308361200004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Doi = {10.1117/1.OE.51.7.071401},
Key = {fds280288}
}
@article{fds280291,
Author = {Kim, MH and Rushmeier, H and Dorsey, J and Harvey, TA and Prum, RO and Kittle, DS and Brady, DJ},
Title = {3D imaging spectroscopy for measuring hyperspectral patterns
on solid objects},
Journal = {Acm Transactions on Graphics},
Volume = {31},
Number = {4},
Pages = {1-11},
Publisher = {Association for Computing Machinery (ACM)},
Year = {2012},
Month = {July},
ISSN = {0730-0301},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000308250300014&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Sophisticated methods for true spectral rendering have been
developed in computer graphics to produce highly accurate
images. In addition to traditional applications in
visualizing appearance, such methods have potential
applications in many areas of scientific study. In
particular, we are motivated by the application of studying
avian vision and appearance. An obstacle to using graphics
in this application is the lack of reliable input data. We
introduce an end-toend measurement system for capturing
spectral data on 3D objects. We present the modification of
a recently developed hyperspectral imager to make it
suitable for acquiring such data in a wide spectral range at
high spectral and spatial resolution. We capture four
megapixel images, with data at each pixel from the
near-ultraviolet (359 nm) to near-infrared (1,003 nm) at 12
nm spectral resolution. We fully characterize the imaging
system, and document its accuracy. This imager is integrated
into a 3D scanning system to enable the measurement of the
diffuse spectral reflectance and fluorescence of specimens.
We demonstrate the use of this measurement system in the
study of the interplay between the visual capabilities and
appearance of birds. We show further the use of the system
in gaining insight into artifacts from geology and cultural
heritage. © 2012 ACM 0730-0301/2012/08-ART38.},
Doi = {10.1145/2185520.2185534},
Key = {fds280291}
}
@article{fds280383,
Author = {Zheng, N and Schmidler, SC and Marks, D and Brady,
D},
Title = {Computer experiment and global optimization of layered
monocentric lens systems},
Journal = {Optik},
Volume = {123},
Number = {14},
Pages = {1249-1259},
Publisher = {Elsevier BV},
Year = {2012},
Month = {July},
ISSN = {0030-4026},
url = {http://dx.doi.org/10.1016/j.ijleo.2011.07.058},
Abstract = {In this paper we derive a general analytical solution for a
monocentric lens system and present a global optimization
method combining sequential design for global optimization
and an expected improvement algorithm for global
optimization for the design and analysis of a layered
monocentric lens system, which provides an "intelligent" way
to search the optimization space based on accumulated
experience. We then apply these methods to an example of
monocentric lens design, and explore the improvement in
system performance obtained through increasing the system
volume. © 2011 Elsevier GmbH. All rights
reserved.},
Doi = {10.1016/j.ijleo.2011.07.058},
Key = {fds280383}
}
@article{fds280384,
Author = {Kittle, DS and Marks, DL and Brady, DJ},
Title = {Design and fabrication of an ultraviolet-visible coded
aperture snapshot spectral imager},
Journal = {Optical Engineering},
Volume = {51},
Number = {7},
Pages = {071403-071403},
Publisher = {SPIE-Intl Soc Optical Eng},
Year = {2012},
Month = {July},
ISSN = {0091-3286},
url = {http://dx.doi.org/10.1117/1.OE.51.7.071403},
Abstract = {We describe the design and performance of a coded aperture
spectral imager with a wide spectral range of 320 to 700nm
over 87 channels and 1988-by-1988 pixels of spatial
resolution. A custom-designed relay lens was designed and
built for the system, including a dispersive prism element
in the collimated space of the relay lens. The optical
design process, prescription, and performance are reported
for the entire system, including calibration and alignment.
Simulations of high-resolution spectral images are conducted
to verify the reconstruction algorithm and relative
resolution of the instrument compared to ground truth data.
Measured data were taken with the instrument using both a
random coded aperture and standard slit for spatial
resolution comparisons. Finally, reconstructed spectral
images from the instrument are presented of a
sunlight-illuminated flower from 360 to 700nm. © 2012
Society of Photo-Optical Instrumentation
Engineers.},
Doi = {10.1117/1.OE.51.7.071403},
Key = {fds280384}
}
@article{fds280387,
Author = {Tremblay, EJ and Marks, DL and Brady, DJ and Ford,
JE},
Title = {Design and scaling of monocentric multiscale
imagers.},
Journal = {Applied Optics},
Volume = {51},
Number = {20},
Pages = {4691-4702},
Year = {2012},
Month = {July},
ISSN = {1559-128X},
url = {http://dx.doi.org/10.1364/ao.51.004691},
Abstract = {Monocentric multi-scale (MMS) lenses are a new approach to
high-resolution wide-angle imaging, where a monocentric
objective lens is shared by an array of identical
rotationally symmetric secondary imagers that each acquire
one overlapping segment of a mosaic. This allows gigapixel
images to be computationally integrated from conventional
image sensors and relatively simple optics. Here we describe
the MMS design space, introducing constraints on image
continuity and uniformity, and show how paraxial system
analysis can provide both volume scaling and a systematic
design methodology for MMS imagers. We provide the detailed
design of a 120° field of viewimager (currently under
construction) resolving 2 gigapixels at 41.5 μrad
instantaneous field of view, and demonstrate reasonable
agreement with the first-order scaling calculation.},
Doi = {10.1364/ao.51.004691},
Key = {fds280387}
}
@article{fds280382,
Author = {Brady, DJ and Gehm, ME and Stack, RA and Marks, DL and Kittle, DS and Golish, DR and Vera, EM and Feller, SD},
Title = {Multiscale gigapixel photography.},
Journal = {Nature},
Volume = {486},
Number = {7403},
Pages = {386-389},
Year = {2012},
Month = {June},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22722199},
Abstract = {Pixel count is the ratio of the solid angle within a
camera's field of view to the solid angle covered by a
single detector element. Because the size of the smallest
resolvable pixel is proportional to aperture diameter and
the maximum field of view is scale independent, the
diffraction-limited pixel count is proportional to aperture
area. At present, digital cameras operate near the
fundamental limit of 1-10 megapixels for millimetre-scale
apertures, but few approach the corresponding limits of
1-100 gigapixels for centimetre-scale apertures. Barriers to
high-pixel-count imaging include scale-dependent geometric
aberrations, the cost and complexity of gigapixel sensor
arrays, and the computational and communications challenge
of gigapixel image management. Here we describe the AWARE-2
camera, which uses a 16-mm entrance aperture to capture
snapshot, one-gigapixel images at three frames per minute.
AWARE-2 uses a parallel array of microcameras to reduce the
problems of gigapixel imaging to those of megapixel imaging,
which are more tractable. In cameras of conventional design,
lens speed and field of view decrease as lens scale
increases, but with the experimental system described here
we confirm previous theoretical results suggesting that lens
speed and field of view can be scale independent in
microcamera-based imagers resolving up to 50 gigapixels.
Ubiquitous gigapixel cameras may transform the central
challenge of photography from the question of where to point
the camera to that of how to mine the data.},
Doi = {10.1038/nature11150},
Key = {fds280382}
}
@article{fds330167,
Author = {Kapadia, A and Samei, E and Harrawood, B and Sahbaee, P and Chawla, A and Tan, Z and Brady, D},
Title = {SU-E-I-77: X-Ray Coherent Scatter Diffraction Pattern
Modeling in GEANT4.},
Journal = {Med Phys},
Volume = {39},
Number = {6Part5},
Pages = {3642-3643},
Year = {2012},
Month = {June},
url = {http://dx.doi.org/10.1118/1.4734794},
Abstract = {PURPOSE: To model X-ray coherent scatter diffraction
patterns in GEANT4 for simulating experiments involving
material detection through diffraction pattern measurement.
Although coherent scatter cross-sections are modeled
accurately in GEANT4, diffraction patterns for crystalline
materials are not yet included. Here we describe our
modeling of crystalline diffraction patterns in GEANT4 for
specific materials and the validation of the results against
experimentally measured data. METHODS: Coherent scatter in
GEANT4 is currently based on Hubbell's non-relativistic form
factor tabulations from EPDL97. We modified the form-factors
by introducing an interference function that accounts for
the angular dependence between the Rayleigh-scattered
photons and the photon wavelength. The modified form factors
were used to replace the inherent form-factors in GEANT4.
The simulation was tested using monochromatic and
polychromatic x-ray beams (separately) incident on objects
containing one or more elements with modified form-factors.
The simulation results were compared against the
experimentally measured diffraction images of corresponding
objects using an in-house x-ray diffraction imager for
validation. The comparison was made using the following
metrics: number of diffraction rings, radial distance,
absolute intensity, and relative intensity. RESULTS: Sharp
diffraction pattern rings were observed in the monochromatic
simulations at locations consistent with the angular
dependence of the photon wavelength. In the polychromatic
simulations, the diffraction patterns exhibited a radial
blur consistent with the energy spread of the polychromatic
spectrum. The simulated and experimentally measured patterns
showed identical numbers of rings with close agreement in
radial distance, absolute and relative intensities (barring
statistical fluctuations). No significant change was
observed in the execution time of the simulations.
CONCLUSIONS: This work demonstrates the ability to model
coherent scatter diffraction in GEANT4 in an accurate and
efficient manner without compromising the accuracy or
runtime of the simulation. This work was supported by the
Department of Homeland Security under grant DHS (BAA 10-01
F075), and by the Department of Defense under award
W81XWH-09-1-0066.},
Doi = {10.1118/1.4734794},
Key = {fds330167}
}
@article{fds280381,
Author = {Heimbeck, MS and Marks, DL and Brady, D and Everitt,
HO},
Title = {Terahertz interferometric synthetic aperture tomography for
confocal imaging systems.},
Journal = {Optics Letters},
Volume = {37},
Number = {8},
Pages = {1316-1318},
Year = {2012},
Month = {April},
ISSN = {0146-9592},
url = {http://dx.doi.org/10.1364/ol.37.001316},
Abstract = {Terahertz (THz) interferometric synthetic aperture
tomography (TISAT) for confocal imaging within extended
objects is demonstrated by combining attributes of synthetic
aperture radar and optical coherence tomography. Algorithms
recently devised for interferometric synthetic aperture
microscopy are adapted to account for the diffraction-and
defocusing-induced spatially varying THz beam width
characteristic of narrow depth of focus, high-resolution
confocal imaging. A frequency-swept two-dimensional TISAT
confocal imaging instrument rapidly achieves in-focus,
diffraction-limited resolution over a depth 12 times larger
than the instrument's depth of focus in a manner that may be
easily extended to three dimensions and greater
depths.},
Doi = {10.1364/ol.37.001316},
Key = {fds280381}
}
@article{fds280233,
Author = {Golish, D and Vera, E and Kelly, K and Gong, Q and Jansen, P and Hughes, J and Kittle, DS and Brady, DJ and Gehm, ME},
Title = {Challenges in gigapixel multiscale image
formation},
Journal = {Imaging Systems and Applications, Isa 2012},
Year = {2012},
Month = {January},
Abstract = {We present new results from the image formation team on the
AWARE Wide-Field project. We will report on new strategies
prompted by new challenges encountered in experiments with
two prototype AWARE Wide-Field systems. © 2012
OSA.},
Key = {fds280233}
}
@article{fds280257,
Author = {Prasad, S and Zhang, Q and Plemmons, R and Brady,
D},
Title = {Statistical performance bounds for coded-aperture
compressive spectral-polarimetric imaging},
Journal = {Computational Optical Sensing and Imaging, Cosi
2012},
Pages = {CTu3B.1},
Year = {2012},
Month = {January},
url = {http://dx.doi.org/10.1364/cosi.2012.ctu3b.1},
Abstract = {We apply statistical information and Bayesian estimation
theories to calculate certain fundamental bounds on the
reconstruction of segment boundaries, material type, and
surface texture of sparse objects from their coded-aperture
compressive spectral-polarimetric image data. © 2012
OSA.},
Doi = {10.1364/cosi.2012.ctu3b.1},
Key = {fds280257}
}
@article{fds280261,
Author = {Brady, DJ},
Title = {Focus in multiscale imaging systems},
Journal = {Computational Optical Sensing and Imaging, Cosi
2012},
Pages = {CM2B.1},
Year = {2012},
Month = {January},
url = {http://dx.doi.org/10.1364/cosi.2012.cm2b.1},
Abstract = {We consider first order lens design for microcamera-based
focus in multiscale cameras, we compare focal and spectral
tomography and we compare dynamic focal scanning with
alternative EDoF and focal stacking strategies. © 2012
OSA.},
Doi = {10.1364/cosi.2012.cm2b.1},
Key = {fds280261}
}
@article{fds280263,
Author = {Golish, D and Vera, E and Kelly, K and Gong, Q and Jansen, P and Hughes, J and Kittle, DS and Brady, DJ and Gehm, ME},
Title = {Challenges in gigapixel multiscale image
formation},
Journal = {Imaging Systems and Applications, Isa 2012},
Pages = {JW3A.4},
Year = {2012},
Month = {January},
url = {http://dx.doi.org/10.1364/cosi.2012.jw3a.4},
Abstract = {We present new results from the image formation team on the
AWARE Wide-Field project. We will report on new strategies
prompted by new challenges encountered in experiments with
two prototype AWARE Wide-Field systems. © 2012
OSA.},
Doi = {10.1364/cosi.2012.jw3a.4},
Key = {fds280263}
}
@article{fds280379,
Author = {Mrozack, A and Marks, DL and Brady, DJ},
Title = {Coded aperture spectroscopy with denoising through
sparsity.},
Journal = {Optics Express},
Volume = {20},
Number = {3},
Pages = {2297-2309},
Year = {2012},
Month = {January},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22330469},
Abstract = {We compare noise and classification metrics for three
aperture codes in dispersive spectroscopy. In contrast with
previous theory, we show that multiplex codes may be
advantageous even in systems dominated by Poisson noise.
Furthermore, ill-conditioned codes with a regularized
estimation strategy are shown to perform competitively with
well-conditioned codes.},
Doi = {10.1364/oe.20.002297},
Key = {fds280379}
}
@article{fds280380,
Author = {McCain, ST and Guenther, BD and Brady, DJ and Krishnamurthy, K and Willett, R},
Title = {Coded-aperture Raman imaging for standoff explosive
detection},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8358},
Publisher = {SPIE},
Year = {2012},
Month = {January},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.919292},
Abstract = {This paper describes the design of a deep-UV Raman imaging
spectrometer operating with an excitation wavelength of 228
nm. The designed system will provide the ability to detect
explosives (both traditional military explosives and
home-made explosives) from standoff distances of 1-10 meters
with an interrogation area of 1 mm x 1 mm to 200 mm x 200
mm. This excitation wavelength provides resonant enhancement
of many common explosives, no background fluorescence, and
an enhanced cross-section due to the inverse wavelength
scaling of Raman scattering. A coded-aperture spectrograph
combined with compressive imaging algorithms will allow for
wide-area interrogation with fast acquisition rates.
Coded-aperture spectral imaging exploits the compressibility
of hyperspectral data-cubes to greatly reduce the amount of
acquired data needed to interrogate an area. The resultant
systems are able to cover wider areas much faster than
traditional push-broom and tunable filter systems. The full
system design will be presented along with initial data from
the instrument. Estimates for area scanning rates and
chemical sensitivity will be presented. The system
components include a solid-state deep-UV laser operating at
228 nm, a spectrograph consisting of well-corrected
refractive imaging optics and a reflective grating, an
intensified solar-blind CCD camera, and a high-efficiency
collection optic. © 2012 SPIE.},
Doi = {10.1117/12.919292},
Key = {fds280380}
}
@article{fds280255,
Author = {Golish, D and Vera, E and Kelly, K and Gong, Q and Jansen, P and Hughes, J and Kittle, DS and Brady, DJ and Gehm, ME},
Title = {Challenges in gigapixel multiscale image
formation},
Journal = {Imaging Systems and Applications, Isa 2012},
Year = {2012},
Key = {fds280255}
}
@article{fds280285,
Author = {Reynolds, and Megan, and Brady, D},
Title = {Bringing You More Than the Weekend: Union Membership and
Self-Rated Health in the U.S.},
Journal = {Social Forces},
Volume = {90},
Number = {3},
Pages = {1023-1049},
Publisher = {Oxford University Press (OUP)},
Year = {2012},
url = {http://www.soc.duke.edu/~brady/web/sf12.pdf},
Abstract = {Previous research suggests that higher incomes, safe
workplaces, job security and healthcare access all
contribute to favorable health. Reflecting the interest of
economic and political sociologists in power relations and
institutions, union membership has been linked with many
such influences on health. Nevertheless, the potential
relationship between union membership and health has
received little attention. Using logistic regression and
propensity score matching, this study examines the
association between union membership and self-rated health
generally and among select subgroups of the workforce with
the General Social Survey from 1973 to 2006. Initial
bivariate analyses suggest that union membership is actually
associated with worse health. This association disappears
when controlling for demographics, then reverses and becomes
significant when controlling for labor market
characteristics. In well-specified models, union membership
has a significant positive effect on favorable self-rated
health. The effect roughly offsets the effects of five years
of aging or being divorced (as opposed to married). In
addition, propensity score matching analyses demonstrate
that union membership has a beneficial, significant average
treatment effect for the treated. We show that much of union
membership's effect in the overall sample is due to the
mechanism of higher incomes, but that among men, the less
educated, and those with lower incomes, the union-health
advantage is not explained fully by income. The effect of
union membership also appears to be stable over time. We
conclude by encouraging further research on how power
relations and institutions shape health. © The Author.
Published by Oxford University Press on behalf of the
University of North Carolina at Chapel Hill. All rights
reserved.},
Doi = {10.1093/sf/sor023},
Key = {fds280285}
}
@article{fds280290,
Author = {Marks, DL and Son, HS and Kim, J and Brady, DJ},
Title = {Engineering a gigapixel monocentric multiscale
camera},
Journal = {Optical Engineering},
Volume = {51},
Number = {8},
Pages = {083202-1},
Publisher = {SPIE-Intl Soc Optical Eng},
Year = {2012},
ISSN = {0091-3286},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000309913000023&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Doi = {10.1117/1.OE.51.8.083202},
Key = {fds280290}
}
@article{fds280365,
Author = {Zhang, Q and Plemmons, R and Kittle, D and Brady, D and Prasad,
S},
Title = {Reconstructing and segmenting hyperspectral images from
compressed measurements},
Journal = {Workshop on Hyperspectral Image and Signal Processing,
Evolution in Remote Sensing},
Publisher = {IEEE},
Year = {2011},
Month = {December},
ISSN = {2158-6276},
url = {http://dx.doi.org/10.1109/WHISPERS.2011.6080939},
Abstract = {A joint reconstruction and segmentation model for
hyperspectral data obtained from a compressive measurement
system is proposed, and some preliminary tests are
described. Although hyperspectral imaging (HSI) technology
has incredible potential, its utility is currently limited
because of the quantity and complexity of the data it
gathers. Yet, often the scene to be reconstructed from the
HSI data contains far less information, typically consisting
of spectrally and spatially homogeneous segments that can be
represented sparsely in an appropriate basis. Such vast
informational redundancy thus implicitly contained in the
HSI data warrants a compressed sensing (CS) strategy that
acquires appropriately coded spectral-spatial data from
which one can reconstruct the original image more
efficiently, while still enabling target identification
procedures. A coded-aperture snapshot spectral imager
(CASSI) is considered here, and a joint reconstruction and
segmentation model for data obtained from CASSI compressive
measurements is proposed and preliminary numerical
experiments are presented. © 2011 IEEE.},
Doi = {10.1109/WHISPERS.2011.6080939},
Key = {fds280365}
}
@article{fds280234,
Author = {Kittle, D and Zhang, Q and Plemmons, R and Brady, D and Prasad,
S},
Title = {Joint segmentation and reconstruction of coded aperture
hyperspectral data},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {This work presents experimental verification of a joint
segmentation reconstruc- tion algorithm on real data from a
snapshot hyperspectral imager. Accurate spectra can be
computed for any pixel location in the data cube. © 2011
Optical Society of America.},
Key = {fds280234}
}
@article{fds280235,
Author = {Xu, Q and Shi, K and Li, H and Choi, K and Horisaki, R and Brady, D and Psaltis, D and Liu, Z},
Title = {In-line holographic CARS microscopy},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {We investigated inline holographic CARS microscopy, in which
the reference generated from a nonlinear medium
co-propagates with the CARS signal produced from a specimen.
We show that this technique has 3D chemical selective
imaging capability. © 2010 Optical Society of
America.},
Key = {fds280235}
}
@article{fds280238,
Author = {Mrozack, A and Marks, DL and Brady, DJ},
Title = {Coded aperture spectroscopy with regularization via convex
optimization},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {Three coded aperture spectrometers are compared for
performance. The classic understanding of performance under
Poisson noise is shown to be incomplete through simulation.
The slit spectrometer code is not the optimal code for
compressible signals. © 2011 OSA.},
Key = {fds280238}
}
@article{fds280242,
Author = {Marks, DL and Brady, DJ and Tremblay, EJ and Ford,
JE},
Title = {Optimizing microcamera aperture in gigapixel monocentric
multiscale cameras},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {Multiscale designs divide the imaging task between a simple
objective and many complex microcameras. We study imaging
quality as the microcamera aperture size varies from 0.375
to 36 mm with 2 and 50 gigapixel objectives. © 2011 Optical
Society of America.},
Key = {fds280242}
}
@article{fds280243,
Author = {Kittle, D and Marks, DL and Kim, MH and Rushmeier, H and Brady,
DJ},
Title = {Design and fabrication of a UV-visible coded aperture
spectral imager (CASI)},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {CASI is a snapshot capable UV-visible spectral imager for
measuring bird plumage. Near apochromatic UV-visible optics
were designed and built with an MTF for a 4Mpx detector.
Wide-spectral bandwidth data from CASI is then presented. ©
2011 Optical Society of America.},
Key = {fds280243}
}
@article{fds280244,
Author = {Lim, S and Marks, DL and Brady, DJ},
Title = {High pixel count holography},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {Relatively low cost focal arrays and the availability of
high performance digital processing enable computational
holographic imaging on unprecedented scale. This talk
describes recent progress in registration and optimization
algorithm. © 2011 Optical Society of America.},
Key = {fds280244}
}
@article{fds280245,
Author = {Brady, DJ},
Title = {Dennis healy, ISP, MONTAGE and MOSAIC},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {Through a series of DARPA programs, Dennis Healy's unique
grasp of the mathematical and physical structure of data and
his equally unique tolerance for implausible ideas
revolutionized the theory of image acquisition. © 2011
OSA.},
Key = {fds280245}
}
@article{fds280246,
Author = {MacCabe, KP and Kittle, DS and Marks, DL and Brady,
DJ},
Title = {Image coding for compressive focal tomography},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {We consider image coding to alias high spatial frequencies
in a focused image into low-frequency components which
survive low-pass defocusing. Coding before defocusing is
shown to structure measurements appropriately for
decompressive inference. © 2011 OSA.},
Key = {fds280246}
}
@article{fds280247,
Author = {Lim, S and Marks, DL and Brady, DJ},
Title = {Sparse aperture holographic synthesis with multiple speckle
realizations},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {Sparse aperture holographic synthesis enables large scale
high resolution imaging with sources in variable states of
coherence. Using incoherent sources increases bandpass
coverage and reduces speckle effects. © 2011 Optical
Society of America.},
Key = {fds280247}
}
@article{fds280248,
Author = {Son, HS and Marks, DL and Tremblay, E and Ford, JE and Hahn, J and Stack,
RA and Johnson, A and McLaughlin, P and Shaw, JM and Kim, J and Brady,
DJ},
Title = {A multiscale, wide field, gigapixel camera},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {Recent investigations into high pixel count imaging using
multiscale optics have led to a novel optical design for a
wide field, gigapixel camera. We review the mechanical
design and optical performance of this imager. © 2011
OSA.},
Key = {fds280248}
}
@article{fds280252,
Author = {Golish, D and Vera, E and Kelly, K and Gong, Q and Brady, DJ and Gehm,
ME},
Title = {Image formation in multiscale optical systems},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {We present image formation (IF) strategies developed for
multiscale imaging systems. In this context, IF takes
advantage of significant prior knowledge of array geometry
and relies on parallelizable algorithms to handle the high
data bandwidth. © 2011 OSA.},
Key = {fds280252}
}
@article{fds280253,
Author = {Marks, DL and Son, HS and Tremblay, EJ and Ford, JE and McLaughlin, PO and Gehm, ME and Stack, RA and Feller, SD and Kim, J and Brady,
DJ},
Title = {Optical testing of the AWARE wide field 2-gigapixel
multiscale camera},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {December},
Abstract = {Testing a 2-Gigapixel 8 arcsec IFOV, 120° FOV camera
requires integration of precision mechanical automation,
optical instrumentation, image diagnostics, electronics and
networking hardware. We detail the ongoing AWARE Wide Field
Camera efforts. © 2011 OSA.},
Key = {fds280253}
}
@article{fds280366,
Author = {Brady, DJ},
Title = {Sampling geometries and resolution limits for compressive
MMW and terahertz imaging},
Journal = {Irmmw Thz 2011 36th International Conference on Infrared,
Millimeter, and Terahertz Waves},
Publisher = {IEEE},
Year = {2011},
Month = {December},
url = {http://dx.doi.org/10.1109/irmmw-THz.2011.6105204},
Abstract = {Compressive measurement enables image formation from sparse
and irregular arrays. In MMW and terahertz imaging,
compressive measurement may lead to a preference for fewer
but more complex transceivers over dense arrays of simple
transceivers (e.g. conventional focal planes). © 2011
IEEE.},
Doi = {10.1109/irmmw-THz.2011.6105204},
Key = {fds280366}
}
@article{fds280377,
Author = {Lim, S and Marks, DL and Brady, DJ},
Title = {Sampling and processing for compressive holography
[Invited].},
Journal = {Applied Optics},
Volume = {50},
Number = {34},
Pages = {H75-H86},
Year = {2011},
Month = {December},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22193030},
Abstract = {Compressive holography applies sparsity priors to data
acquired by digital holography to infer a small number of
object features or basis vectors from a slightly larger
number of discrete measurements. Compressive holography may
be applied to reconstruct three-dimensional (3D) images from
two-dimensional (2D) measurements or to reconstruct 2D
images from sparse apertures. This paper is a tutorial
covering practical compressive holography procedures,
including field propagation, reference filtering, and
inverse problems in compressive holography. We present as
examples 3D tomography from a 2D hologram, 2D image
reconstruction from a sparse aperture, and diffuse object
estimation from diverse speckle realizations.},
Doi = {10.1364/ao.50.000h75},
Key = {fds280377}
}
@article{fds280378,
Author = {Li, S and Moskal, J and Kokar, MM and Brady, D},
Title = {An implementation of collaborative adaptation of cognitive
radio parameters using an ontology and policy based
approach},
Journal = {Analog Integrated Circuits and Signal Processing},
Volume = {69},
Number = {2-3},
Pages = {283-296},
Publisher = {Springer Nature},
Year = {2011},
Month = {December},
ISSN = {0925-1030},
url = {http://dx.doi.org/10.1007/s10470-011-9681-y},
Abstract = {The main objective of this paper is to demonstrate the
feasibility of the ontology and policy based approach to
realize collaborative, automatic adaptation of cognitive
radio parameters in the transmitter and receiver. The
ontology and policy based approach features the following
three aspects. First, all the internal and external
information of the radio is represented in the Web Ontology
Language (OWL). The transmitter and receiver share the same
core ontology and thus can communicate with each other using
this common language. Second, the policy rules are written
in a declarative form and interpreted by a reasoner. Third,
in order to exchange the OWL represented information between
the radios, we adopt a more flexible signaling plan, which
is different than the conventional protocol-predefined
signaling plan, i.e. the control messages are added to an
extendable payload, rather than embedded in the predefined
protocol-dependent header or trailer. The paper discusses
the implementation and shows some examples of radio
behaviors resulting from the execution of the policies. ©
2011 Springer Science+Business Media, LLC.},
Doi = {10.1007/s10470-011-9681-y},
Key = {fds280378}
}
@article{fds280375,
Author = {Marks, DL and Tremblay, EJ and Ford, JE and Brady,
DJ},
Title = {Microcamera aperture scale in monocentric gigapixel
cameras.},
Journal = {Applied Optics},
Volume = {50},
Number = {30},
Pages = {5824-5833},
Year = {2011},
Month = {October},
url = {http://www.ncbi.nlm.nih.gov/pubmed/22015411},
Abstract = {Multiscale cameras achieve wide-angle, high-resolution
imaging by combining coarse image formation by a simplified
wide-field objective with localized aberration correction in
an array of narrow field microcameras. Microcamera aperture
size is a critical parameter in multiscale design; a larger
aperture has greater capacity to correct aberration but
requires a more complex microcamera optic. A smaller
aperture requires integration of more microcameras to cover
the field. This paper analyzes multiscale system performance
as a function of microcamera aperture for 2 and 40 gigapixel
monocentric objective lenses. We find that microcamera
aperture diameters of 3 to 12 mm paired with complementary
metal oxide semiconductor sensors in the 1 to 15 megapixel
range are most attractive for gigapixel-scale
cameras.},
Doi = {10.1364/ao.50.005824},
Key = {fds280375}
}
@article{fds280362,
Author = {Zhang, Q and Plemmons, RJ and Kittle, D and Brady, D and Prasad,
S},
Title = {Joint segmentation and reconstruction of hyperspectral
images from a single snapshot},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8048},
Year = {2011},
Month = {September},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.881777},
Abstract = {This work describes numerical methods for the joint
reconstruction and segmentation of spectral images taken by
compressive sensing coded aperture snapshot spectral imagers
(CASSI). In a snapshot, a CASSI captures a two-dimensional
(2D) array of measurements that is an encoded representation
of both spectral information and 2D spatial information of a
scene, resulting in significant savings in acquisition time
and data storage. The double disperser coded aperture
snapshot imager (DD-CASSI) is able to capture a
hyperspectral image from which a highly underdetermined
inverse problem is solved for the original hyperspectral
cube with regularization terms such as total variation
minimization. The reconstruction process decodes the 2D
measurements to render a three-dimensional spatio-spectral
estimate of the scene, and is therefore an indispensable
component of the spectral imager. In this study, we seek a
particular form of the compressed sensing solution that
assumes spectrally homogeneous segments in the two spatial
dimensions, and greatly reduces the number of unknowns. The
proposed method generalizes popular active contour
segmentation algorithms such as the Chan-Vese model and also
enables one to jointly estimate both the segmentation
membership functions and the spectral signatures of each
segment. The results are illustrated on a simulated Hubble
Space Satellite hyperspectral dataset, a real urban
hyperspectral dataset, and a real DD-CASSI image in
microscopy. © 2011 Copyright Society of Photo-Optical
Instrumentation Engineers (SPIE).},
Doi = {10.1117/12.881777},
Key = {fds280362}
}
@article{fds280363,
Author = {Xu, Q and Shi, K and Li, H and Choi, K and Horisaki, R and Brady, D and Psaltis, D and Liu, Z},
Title = {In-line holographic CARS microscopy},
Journal = {2011 Conference on Lasers and Electro Optics: Laser Science
to Photonic Applications, Cleo 2011},
Year = {2011},
Month = {September},
Abstract = {We investigated inline holographic CARS microscopy, in which
the reference generated from a nonlinear medium
co-propagates with the CARS signal produced from a specimen.
We show that this technique has 3D chemical selective
imaging capability. © 2011 OSA.},
Key = {fds280363}
}
@article{fds280364,
Author = {Brady, DJ and Lim, S},
Title = {Gigapixel holography},
Journal = {2011 Ico International Conference on Information Photonics,
Ip 2011},
Publisher = {IEEE},
Year = {2011},
Month = {August},
url = {http://dx.doi.org/10.1109/ICO-IP.2011.5953763},
Abstract = {Relatively low cost focal plane arrays and the availability
of high performance digital memory and processing enable
computational holographic imaging on unprecedented scale.
Recent progress in registration and optimization enables
coherent imaging over relatively large sensor arrays based
on scanning. This talk describes work on large pixel count
holographic imaging in our group and discusses multi-sensor
array image fusion in computational holographic imagers. ©
2011 IEEE.},
Doi = {10.1109/ICO-IP.2011.5953763},
Key = {fds280364}
}
@article{fds280374,
Author = {Son, HS and Marks, DL and Hahn, J and Kim, J and Brady,
DJ},
Title = {Design of a spherical focal surface using close-packed relay
optics.},
Journal = {Optics Express},
Volume = {19},
Number = {17},
Pages = {16132-16138},
Year = {2011},
Month = {August},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21934976},
Abstract = {This paper presents a design strategy for close-packing
circular finite-conjugate optics to create a spherical focal
surface. Efficient packing of circles on a sphere is
commonly referred to as the Tammes problem and various
methods for packing optimization have been investigated,
such as iterative point-repulsion simulations. The method
for generating the circle distributions proposed here is
based on a distorted icosahedral geodesic. This has the
advantages of high degrees of symmetry, minimized variations
in circle separations, and computationally inexpensive
generation of configurations with N circles, where N is the
number of vertices on the geodesic. These properties are
especially beneficial for making a continuous focal surface
and results show that circle packing densities near
steady-state maximum values found with other methods can be
achieved.},
Doi = {10.1364/OE.19.016132},
Key = {fds280374}
}
@article{fds280372,
Author = {Zhang, Q and Plemmons, R and Kittle, D and Brady, D and Prasad,
S},
Title = {Joint segmentation and reconstruction of hyperspectral data
with compressed measurements.},
Journal = {Applied Optics},
Volume = {50},
Number = {22},
Pages = {4417-4435},
Year = {2011},
Month = {August},
ISSN = {1559-128X},
url = {http://dx.doi.org/10.1364/ao.50.004417},
Abstract = {This work describes numerical methods for the joint
reconstruction and segmentation of spectral images taken by
compressive sensing coded aperture snapshot spectral imagers
(CASSI). In a snapshot, a CASSI captures a two-dimensional
(2D) array of measurements that is an encoded representation
of both spectral information and 2D spatial information of a
scene, resulting in significant savings in acquisition time
and data storage. The reconstruction process decodes the 2D
measurements to render a three-dimensional spatio-spectral
estimate of the scene and is therefore an indispensable
component of the spectral imager. In this study, we seek a
particular form of the compressed sensing solution that
assumes spectrally homogeneous segments in the two spatial
dimensions, and greatly reduces the number of unknowns,
often turning the underdetermined reconstruction problem
into one that is overdetermined. Numerical tests are
reported on both simulated and real data representing
compressed measurements.},
Doi = {10.1364/ao.50.004417},
Key = {fds280372}
}
@article{fds280373,
Author = {Brady, DJ and Marks, DL},
Title = {Coding for compressive focal tomography.},
Journal = {Applied Optics},
Volume = {50},
Number = {22},
Pages = {4436-4449},
Year = {2011},
Month = {August},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21833119},
Abstract = {We consider the capabilities and limits of strategies for
single-aperture three-dimensional and extended depth of
field optical imaging. We show that reduced spatial
resolution is implicit in forward models for light field
sampling and that reduced modulation transfer efficiency is
intrinsic to pupil coding. We propose a novel strategy based
on image space modulation and show that this strategy can be
sensitive to high-resolution spatial features across an
extended focal volume.},
Doi = {10.1364/ao.50.004436},
Key = {fds280373}
}
@article{fds280376,
Author = {Hahn, J and Marks, DL and Choi, K and Lim, S and Brady,
DJ},
Title = {Thin holographic camera with integrated reference
distribution.},
Journal = {Applied Optics},
Volume = {50},
Number = {24},
Pages = {4848-4854},
Year = {2011},
Month = {August},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21857709},
Abstract = {Off-axis digital holography typically uses a beam splitter
to combine reference and object waves at an angle matched to
the sampling period of the sensor array. The beam splitter
determines the thickness of the recording system. This paper
describes and demonstrates a total internal reflection
hologram that replaces the beam splitter and enables
hologram recording over a large aperture with a thin
camera.},
Doi = {10.1364/ao.50.004848},
Key = {fds280376}
}
@article{fds280360,
Author = {Gehm, ME and Golish, DR and Vera, EM and Hahn, J and Marks, DL and Brady,
DJ},
Title = {Image formation challenges in the MOSAIC
platform},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8056},
Publisher = {SPIE},
Year = {2011},
Month = {July},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.883695},
Abstract = {The DARPA MOSAIC program applies multiscale optical design
(shared objective lens and parallel array of microcameras)
to the acquisition of high pixel count images.
Interestingly, these images present as many challenges as
opportunities. The imagery is acquired over many slightly
overlapping fields with diverse focal, exposure and temporal
parameters. Estimation of a consensus image, display of
imagery at human-comprehensible resolutions, automated
anomaly detection to guide viewer attention, and power
management in a distributed electronic environment are just
a few of the novel challenges that arise. This talk
describes some of these challenges and presents progress to
date. © 2011 SPIE.},
Doi = {10.1117/12.883695},
Key = {fds280360}
}
@article{fds280371,
Author = {Lim, S and Choi, K and Hahn, J and Marks, DL and Brady,
DJ},
Title = {Image-based registration for synthetic aperture
holography.},
Journal = {Optics Express},
Volume = {19},
Number = {12},
Pages = {11716-11731},
Year = {2011},
Month = {June},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21716403},
Abstract = {High pixel count apertures for digital holography may be
synthesized by scanning smaller aperture detector arrays.
Characterization and compensation for registration errors in
the detector array position and pitch and for phase
instability between the reference and object field is a
major challenge in scanned systems. We use a secondary
sensor to monitor phase and image-based registration
parameter estimators to demonstrate near diffraction-limited
resolution from a 63.4 mm aperture synthesized by scanning a
5.28 mm subaperture over 144 transverse positions. We
demonstrate 60 μm resolution at 2 m range.},
Doi = {10.1364/oe.19.011716},
Key = {fds280371}
}
@article{fds280361,
Author = {Kianirad, E and Gamache, RW and Brady, D and Alshawabkeh,
AN},
Title = {Equivalent quasi-static estimation of dynamic penetration
force for near surface soil characterization},
Journal = {Geotechnical Special Publication},
Number = {211 GSP},
Pages = {2325-2334},
Publisher = {American Society of Civil Engineers},
Year = {2011},
Month = {May},
ISSN = {0895-0563},
url = {http://dx.doi.org/10.1061/41165(397)238},
Abstract = {This paper describes the application of maximum
log-likelihood estimation to estimate the average force
during a dynamic penetration. It is used to obtain a quasi-
static equivalent of the dynamic force in Rapid Soil
Characterization System (RapSochs). The force is measured at
the tip and friction sleeve by strain gauges during hammer
blows. The results are necessary for any analyses similar to
Cone Penetration Test (CPT) data analysis. This method is
proven to result in an acceptable estimation of the force
(the soil resistance) in different soil types. It is shown
that the cone resistance, friction resistance and friction
ratio similar to CPT can be obtained and these are plotted
versus depth. It is also shown that the estimated soil
resistance does not depend on the applied energy and
variable hammer drop height. © 2011 ASCE.},
Doi = {10.1061/41165(397)238},
Key = {fds280361}
}
@article{fds280359,
Author = {Chen, S and Li, P and Brady, D and Lehman, B},
Title = {Optimum inverter sizing in consideration of irradiance
pattern and PV incentives},
Journal = {Conference Proceedings Ieee Applied Power Electronics
Conference and Exposition Apec},
Pages = {982-988},
Publisher = {IEEE},
Year = {2011},
Month = {May},
url = {http://dx.doi.org/10.1109/APEC.2011.5744714},
Abstract = {This paper proposes a general method of sizing the inverter
for a PV system. The method evaluates effects of PV
incentive policies, inverter efficiency curves, and inverter
protection schemes on optimum inverter sizing through
system-level cost analysis. Specifically, different
scenarios of PV incentives are discussed and compared to
show that the optimal inverter size varies notably by
location and context. © 2011 IEEE.},
Doi = {10.1109/APEC.2011.5744714},
Key = {fds280359}
}
@article{fds280368,
Author = {Tang, Y and Vlahovic, B and Brady, DJ},
Title = {Metallic nano-structures for polarization-independent
multi-spectral filters.},
Journal = {Nanoscale Research Letters},
Volume = {6},
Number = {1},
Pages = {394},
Year = {2011},
Month = {May},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21711927},
Abstract = {Cross-shaped-hole arrays (CSHAs) are selected for
diminishing the polarization-dependent transmission
differences of incident plane waves. We investigate the
light transmission spectrum of the CSHAs in a thin gold film
over a wide range of features. It is observed that two
well-separated and high transmission efficiency peaks could
be obtained by designing the parameters in the CSHAs for
both p-polarized and s-polarized waves; and a nice
transmission band-pass is also observed by specific
parameters of a CSHA too. It implicates the possibility to
obtain a desired polarization-independent transmission
spectrum from the CSHAs by designing their parameters. These
findings provide potential applications of the metallic
nano-structures in optical filters, optical band-pass,
optical imaging, optical sensing, and biosensors.},
Doi = {10.1186/1556-276x-6-394},
Key = {fds280368}
}
@article{fds280369,
Author = {Brady, DJ},
Title = {Reply to "Comments on multiple aperture cameras},
Journal = {Applied Optics},
Volume = {50},
Number = {11},
Pages = {1587-1592},
Publisher = {The Optical Society},
Year = {2011},
Month = {April},
ISSN = {1559-128X},
url = {http://dx.doi.org/10.1364/AO.50.001587},
Abstract = {In response to "Comments on 'Design and characterization of
thin multiple aperture infrared cameras,'" Appl. Opt. 50,
1584 (2011), I explain how aliasing and regularization
impact noise scaling in multiple aperture imagers. © 2011
Optical Society of America.},
Doi = {10.1364/AO.50.001587},
Key = {fds280369}
}
@article{fds280370,
Author = {Hahn, J and Lim, S and Choi, K and Horisaki, R and Brady,
DJ},
Title = {Video-rate compressive holographic microscopic
tomography.},
Journal = {Optics Express},
Volume = {19},
Number = {8},
Pages = {7289-7298},
Year = {2011},
Month = {April},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21503040},
Abstract = {Compressive holography enables 3D reconstruction from a
single 2D holographic snapshot for objects that can be
sparsely represented in some basis. The snapshot mode
enables tomographic imaging of microscopic moving objects.
We demonstrate video-rate tomographic image acquisition of
two live water cyclopses with 5.2 μm spatial resolution and
60 μm axial resolution.},
Doi = {10.1364/oe.19.007289},
Key = {fds280370}
}
@article{fds280367,
Author = {Marks, DL and Brady, DJ},
Title = {Close-up imaging using microcamera arrays for focal plane
synthesis},
Journal = {Optical Engineering},
Volume = {50},
Number = {3},
Pages = {033205-033205},
Publisher = {SPIE-Intl Soc Optical Eng},
Year = {2011},
Month = {March},
ISSN = {0091-3286},
url = {http://dx.doi.org/10.1117/1.3554389},
Abstract = {Conventional close-up imaging uses lens arrays to form a
continuous image of an extended object on a single focal
plane sensor or photographic film. By imaging using
microcamera arrays onto many separate sensors rather than a
single large sensor, the subfields captured by individual
sensors may be combined using image processing into a large
synthetic image plane. This greatly increases the
flexibility of the close-up imaging design because it is no
longer required that the close up image be continuous. Using
microcamera arrays, hundreds or thousands of megapixel
sensors may be combined to form a synthetic gigapixel-scale
sensor. This paper is an investigation into the design
issues of microcamera arrays, and presents a simple design
of a lens suitable for a megapixel class microcamera. ©
2011 Society of Photo-Optical Instrumentation Engineers
(SPIE).},
Doi = {10.1117/1.3554389},
Key = {fds280367}
}
@article{fds280254,
Author = {Golish, D and Vera, E and Kelly, K and Gong, Q and Brady, DJ and Gehm,
ME},
Title = {Image formation in multiscale optical systems},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
Month = {January},
ISSN = {2162-2701},
url = {http://dx.doi.org/10.1364/cosi.2011.jtue4},
Abstract = {We present image formation (IF) strategies developed for
multiscale imaging systems. In this context, IF takes
advantage of significant prior knowledge of array geometry
and relies on parallelizable algorithms to handle the high
data bandwidth. © 2011 OSA.},
Doi = {10.1364/cosi.2011.jtue4},
Key = {fds280254}
}
@article{fds280230,
Author = {Marks, DL and Brady, DJ and Tremblay, EJ and Ford,
JE},
Title = {Optimizing microcamera aperture in gigapixel monocentric
multiscale cameras},
Journal = {Optics Infobase Conference Papers},
Publisher = {Optical Society of America},
Year = {2011},
Abstract = {Multiscale designs divide the imaging task between a simple
objective and many complex microcameras. We study imaging
quality as the microcamera aperture size varies from 0.375
to 36 mm with 2 and 50 gigapixel objectives. © 2011 Optical
Society of America.},
Key = {fds280230}
}
@article{fds280231,
Author = {Golish, D and Vera, E and Kelly, K and Gong, Q and Brady, DJ and Gehm,
ME},
Title = {Image formation in multiscale optical systems},
Journal = {Optics Infobase Conference Papers},
Publisher = {Optical Society of America},
Year = {2011},
Abstract = {We present image formation (IF) strategies developed for
multiscale imaging systems. In this context, IF takes
advantage of significant prior knowledge of array geometry
and relies on parallelizable algorithms to handle the high
data bandwidth. © 2011 OSA.},
Key = {fds280231}
}
@article{fds280232,
Author = {Son, HS and Marks, DL and Tremblay, E and Ford, JE and Hahn, J and Stack,
RA and Johnson, A and McLaughlin, P and Shaw, JM and Kim, J and Brady,
DJ},
Title = {A multiscale, wide field, gigapixel camera},
Journal = {Optics Infobase Conference Papers},
Publisher = {Optical Society of America},
Year = {2011},
Abstract = {Recent investigations into high pixel count imaging using
multiscale optics have led to a novel optical design for a
wide field, gigapixel camera. We review the mechanical
design and optical performance of this imager. © 2011
OSA.},
Key = {fds280232}
}
@article{fds280240,
Author = {Marks, DL and Brady, DJ and Tremblay, EJ and Ford,
JE},
Title = {Optimizing microcamera aperture in gigapixel monocentric
multiscale cameras},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
ISSN = {2162-2701},
Key = {fds280240}
}
@article{fds280241,
Author = {Son, HS and Marks, DL and Tremblay, E and Ford, JE and Hahn, J and Stack,
RA and Johnson, A and McLaughlin, P and Shaw, JM and Kim, J and Brady,
DJ},
Title = {A multiscale, wide field, gigapixel camera},
Journal = {Optics Infobase Conference Papers},
Year = {2011},
ISSN = {2162-2701},
Key = {fds280241}
}
@article{fds280398,
Author = {Westphal, A and Rulkov, NF and Ayers, J and Brady, D and Hunt,
M},
Title = {Controlling a lamprey-based robot with an electronic nervous
system},
Journal = {Smart Structures and Systems},
Volume = {7},
Number = {6},
Pages = {471-484},
Year = {2011},
ISSN = {1738-1584},
Abstract = {We are developing a biomimetic robot based on the Sea
Lamprey. The robot consists of a cylindrical electronics bay
propelled by an undulatory body axis. Shape memory alloy
(SMA) actuators generate propagating flexion waves in five
undulatory segments of a polyurethane strip. The behavior of
the robot is controlled by an electronic nervous system
(ENS) composed of networks of discrete-time map-based
neurons and synapses that execute on a digital signal
processing chip. Motor neuron action potentials gate power
transistors that apply current to the SMA actuators. The ENS
consists of a set of segmental central pattern generators
(CPGs), modulated by layered command and coordinating neuron
networks, that integrate input from exteroceptive sensors
including a compass, accelerometers, inclinometers and a
short baseline sonar array (SBA). The CPGs instantiate the
3-element hemi-segmental network model established from
physiological studies. Anterior and posterior propagating
pathways between CPGs mediate intersegmental coordination to
generate flexion waves for forward and backward swimming.
The command network mediates layered exteroceptive reflexes
for homing, primary orientation, and impediment
compensation. The SBA allows homing on a sonar beacon by
indicating deviations in azimuth and inclination.
Inclinometers actuate a bending segment between the hull and
undulator to allow climb and dive. Accelerometers can
distinguish collisions from impediment to allow compensatory
reflexes. Modulatory commands mediate speed control and
turning. A SBA communications interface is being developed
to allow supervised reactive autonomy.},
Key = {fds280398}
}
@article{fds280399,
Author = {Westphal, A and Rulkov, NF and Ayers, J and Brady, D and Hunt,
M},
Title = {Controlling a lamprey-based robot with an electronic nervous
system},
Journal = {Smart Structures and Systems},
Volume = {8},
Number = {1},
Pages = {39-52},
Year = {2011},
ISSN = {1738-1584},
Abstract = {We are developing a biomimetic robot based on the Sea
Lamprey. The robot consists of a cylindrical electronics bay
propelled by an undulatory body axis. Shape memory alloy
(SMA) actuators generate propagating flexion waves in five
undulatory segments of a polyurethane strip. The behavior of
the robot is controlled by an electronic nervous system
(ENS) composed of networks of discrete-time map-based
neurons and synapses that execute on a digital signal
processing chip. Motor neuron action potentials gate power
transistors that apply current to the SMA actuators. The ENS
consists of a set of segmental central pattern generators
(CPGs), modulated by layered command and coordinating neuron
networks, that integrate input from exteroceptive sensors
including a compass, accelerometers, inclinometers and a
short baseline sonar array (SBA). The CPGs instantiate the
3-element hemi-segmental network model established from
physiological studies. Anterior and posterior propagating
pathways between CPGs mediate intersegmental coordination to
generate flexion waves for forward and backward swimming.
The command network mediates layered exteroceptive reflexes
for homing, primary orientation, and impediment
compensation. The SBA allows homing on a sonar beacon by
indicating deviations in azimuth and inclination.
Inclinometers actuate a bending segment between the hull and
undulator to allow climb and dive. Accelerometers can
distinguish collisions from impediment to allow compensatory
reflexes. Modulatory commands mediate speed control and
turning. A SBA communications interface is being developed
to allow supervised reactive autonomy.},
Key = {fds280399}
}
@article{fds280346,
Author = {Brady, DJ and Mrozack, A and Choi, K},
Title = {Sparse aperture coding for compressive sampling},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7818},
Publisher = {SPIE},
Year = {2010},
Month = {December},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.862159},
Abstract = {For many years, the basic goal of sparse aperture design has
been to maximize the support of the modulation transfer
function (MTF). Golay apertures and related nonredundant
arrays are typically used to achieve this objective.
Unfortunately, maximizing the support of the MTF has the
necessary effect of decreasing the magnitude of the MTF at
mid-band spatial frequencies. Fienup has shown that the
decreased magnitude of the MTF for nonredundant arrays
contributes as much as reduced throughput to the loss of SNR
in sparse apertures relative to full aperture systems. This
paper considers the use of periodic sparse arrays to improve
the mid-band MTF at the cost of reduced spatial frequency
coverage. We further consider methods to recover lost
spatial frequencies using multispectral and multiframe
sampling and decompressive inference. © 2010
SPIE.},
Doi = {10.1117/12.862159},
Key = {fds280346}
}
@article{fds280176,
Author = {Fernandez-Cull, C and Brady, D and Wikner, DA and Mait,
JN},
Title = {Sparse fourier sampling in millimeter-wave compressive
holography},
Journal = {Optics Infobase Conference Papers},
Year = {2010},
Month = {December},
ISSN = {2162-2701},
Abstract = {We analyze the impact of sparse sampling on millimeter-wave
(MMW) two-dimensional (2D) holographic measurements for
three-dimensional (3D) object reconstruction. Simulations
address 3D object estimation efficacy. We present 3D object
reconstructions from experimental data. © 2009 Optical
Society of America.},
Key = {fds280176}
}
@article{fds280178,
Author = {Brady, D and Choi, K and Horisaki, R and Hahn, J and Lim,
S},
Title = {Compressive holography of di®use scatterers},
Journal = {Optics Infobase Conference Papers},
Year = {2010},
Month = {December},
ISSN = {2162-2701},
Abstract = {We image the incoherent 3D scattering density of objects
from the covariance of 2D scattered speckle -eld
measurements using forward model regularization and
constrained optimization. 3D resolution consistent with
spatial bandlimits is demonstrated. © 2009 Optical Society
of America.},
Key = {fds280178}
}
@article{fds280223,
Author = {Guo, J and Leong, HS and Lindquist, RG and Brady,
DJ},
Title = {Integrated nano-hole array surface plasmon resonance
biochemical sensor},
Journal = {Optics Infobase Conference Papers},
Year = {2010},
Month = {December},
Abstract = {We have demonstrated a super-periodic metallic nano-hole
array surface plasmon device for integrated biochemical
sensing. The super-periodic nano-hole array device combines
functions of sensing and surface plasmon resonance spectral
analysis on a single device. © 2010 OSA/FiO/LS
2010.},
Key = {fds280223}
}
@article{fds280224,
Author = {Hahn, J and Lim, S and Choi, K and Horisaki, R and Marks, DL and Brady,
DJ},
Title = {Compressive holographic microscopy},
Journal = {Optics Infobase Conference Papers},
Year = {2010},
Month = {December},
Abstract = {We demonstrate a snapshot 3D holographic microscopy using
decompressive inference to infer a tomographic image from a
Gabor hologram and to remove autocorrelation and twin-image
terms. © 2009 Optical Society of America.},
Key = {fds280224}
}
@article{fds280229,
Author = {Marks, DL and Brady, DJ},
Title = {Gigagon: A monocentric lens design imaging 40
gigapixels},
Journal = {Optics Infobase Conference Papers},
Year = {2010},
Month = {December},
Abstract = {The Gigagon is a f/2.5 five element monocentric lens
resolving under 2 arcsec over a 120 degree field of view
intended to image onto megapixel sensors tiled over the
focal surface. © 2010 Optical Society of
America.},
Key = {fds280229}
}
@article{fds280348,
Author = {Zambrano-Nuñez, M and Marengo, EA and Brady, D},
Title = {Cramer-rao study of scattering systems in one-dimensional
space},
Journal = {Proceedings of the Iasted International Conference on
Antennas, Radar and Wave Propagation, Arp
2010},
Pages = {58-64},
Publisher = {ACTA Press},
Year = {2010},
Month = {December},
url = {http://dx.doi.org/10.2316/P.2010.705-001},
Abstract = {A Cramer-Rao bound (CRB) study is developed to characterize
the information content about scattering parameters that is
contained in reflective (R), transmissive (T), and combined
R plus T wave scattering data. The analysis is developed for
scalar wave scattering systems in onedimensional space,
paying particular attention to elastic scatterers, which
simplifies the signal model (relative to more general
scattering systems), thereby allowing closedform expressions
for the CRB for special cases. The derived CRB results
quantify the effect of multiple scattering, be it in
enhancing or in diminishing imaging capabilities, relative
to the Born approximation model which is customarily used as
the standard reference for resolution limits. The paper also
discusses the role of the measurement configuration for
scatterer information extraction (e.g., reflective data
applicable to monostatic radar, versus transmissive data
applicable to bistatic radar).},
Doi = {10.2316/P.2010.705-001},
Key = {fds280348}
}
@article{fds280357,
Author = {Kittle, D and Choi, K and Wagadarikar, A and Brady,
DJ},
Title = {Multiframe image estimation for coded aperture snapshot
spectral imagers.},
Journal = {Applied Optics},
Volume = {49},
Number = {36},
Pages = {6824-6833},
Year = {2010},
Month = {December},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21173812},
Abstract = {A coded aperture snapshot spectral imager (CASSI) estimates
the three-dimensional spatiospectral data cube from a
snapshot two-dimensional coded projection, assuming that the
scene is spatially and spectrally sparse. For less
spectrally sparse scenes, we show that the use of multiple
nondegenerate snapshots can make data cube recovery less
ill-posed, yielding improved spatial and spectral
reconstruction fidelity. Additionally, data acquisition can
be easily scaled to meet the time/resolution requirements of
the scene with little modification or extension of the
original CASSI hardware. A multiframe reconstruction of a
640 × 480 × 53 voxel datacube with 450-650 nm white-light
illumination of a scene reveals substantial improvement in
the reconstruction fidelity, with limited increase in
acquisition and reconstruction time.},
Doi = {10.1364/ao.49.006824},
Key = {fds280357}
}
@article{fds280358,
Author = {Choi, K and Horisaki, R and Hahn, J and Lim, S and Marks, DL and Schulz,
TJ and Brady, DJ},
Title = {Compressive holography of diffuse objects.},
Journal = {Applied Optics},
Volume = {49},
Number = {34},
Pages = {H1-10},
Year = {2010},
Month = {December},
url = {http://www.ncbi.nlm.nih.gov/pubmed/21124522},
Abstract = {We propose an estimation-theoretic approach to the inference
of an incoherent 3D scattering density from 2D scattered
speckle field measurements. The object density is derived
from the covariance of the speckle field. The inference is
performed by a constrained optimization technique inspired
by compressive sensing theory. Experimental results
demonstrate and verify the performance of our
estimates.},
Doi = {10.1364/ao.49.0000h1},
Key = {fds280358}
}
@article{fds280347,
Author = {Marks, DL and Hahn, J and Horisaki, R and Brady, DJ},
Title = {Computational photography and compressive
holography},
Journal = {2010 Ieee International Conference on Computational
Photography, Iccp 2010},
Publisher = {IEEE},
Year = {2010},
Month = {November},
url = {http://dx.doi.org/10.1109/ICCPHOT.2010.5585090},
Abstract = {As lasers, photosensors, and computational imaging
techniques improve, holography becomes an increasingly
attractive approach for imaging applications largely re-
served for photography. For the same illumination energy, we
show that holography and photography have nearly identical
noise performance. Because the coherent field is two
dimensional outside of a source, there is ambiguity in
inferring the three-dimensional structure of a source from
the coherent field. Compressive holography overcomes this
limitation by imposing sparsity constraints on the three-
dimensional scatterer, which greatly reduces the number of
possibilities allowing reliable inference of structure. We
demonstrate the use of compressive holography to infer the
three-dimensional structure of a scene comprising two toys
© 2010 IEEE.},
Doi = {10.1109/ICCPHOT.2010.5585090},
Key = {fds280347}
}
@article{fds280344,
Author = {Chen, S and Li, P and Brady, D and Lehman, B},
Title = {The impact of irradiance time behaviors on inverter sizing
and design},
Journal = {2010 Ieee 12th Workshop on Control and Modeling for Power
Electronics, Compel 2010},
Publisher = {IEEE},
Year = {2010},
Month = {October},
url = {http://dx.doi.org/10.1109/COMPEL.2010.5562387},
Abstract = {This paper investigates the time behavior of over-irradiance
events in which the photovoltaic (PV) array outputs more
power than the rated power of the inverter. A new dynamic
interpretation of such events is proposed and is compared to
the conventional static viewpoint. Facts revealed under such
dynamic view may lead to new guidelines for system
integrators and inverter designers in both sizing and
designing inverters. A way to extend overload operation time
of inverters is also proposed.},
Doi = {10.1109/COMPEL.2010.5562387},
Key = {fds280344}
}
@article{fds280356,
Author = {Tang, Y and Vlahovic, B and Brady, DJ},
Title = {Light propagating in metal sub-wavelength-hole
arrays},
Journal = {Nano},
Volume = {5},
Number = {5},
Pages = {295-300},
Publisher = {World Scientific Pub Co Pte Lt},
Year = {2010},
Month = {October},
ISSN = {1793-2920},
url = {http://dx.doi.org/10.1142/S1793292010002207},
Abstract = {We investigate the light propagating through a
sub-wavelength-hole array in a thin gold film. The
extraordinary light transmission (ELT) of the metallic array
is observed. This ELT is due to the localized plasmon
polaritons, whose production are dependent on the
polarization of the light, the periodicity of the array, the
features of the hole, and the thickness of the gold film.
These parameters of the metallic structures are investigated
through the finite difference time domain method. It is
possible to obtain a desired transmission spectrum from the
sub-wavelength-hole array by designing these parameters. ©
2010 World Scientific Publishing Company.},
Doi = {10.1142/S1793292010002207},
Key = {fds280356}
}
@article{fds280353,
Author = {Zheng, N and Hagen, N and Brady, DJ},
Title = {Analytic-domain lens design with proximate ray
tracing.},
Journal = {Journal of the Optical Society of America
A},
Volume = {27},
Number = {8},
Pages = {1791-1802},
Year = {2010},
Month = {August},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20686583},
Abstract = {We have developed an alternative approach to optical design
which operates in the analytical domain so that an optical
designer works directly with rays as analytical functions of
system parameters rather than as discretely sampled
polylines. This is made possible by a generalization of the
proximate ray tracing technique which obtains the analytical
dependence of the rays at the image surface (and ray path
lengths at the exit pupil) on each system parameter. The
resulting method provides an alternative direction from
which to approach system optimization and supplies
information which is not typically available to the system
designer. In addition, we have further expanded the
procedure to allow asymmetric systems and arbitrary order of
approximation, and have illustrated the performance of the
method through three lens design examples.},
Doi = {10.1364/josaa.27.001791},
Key = {fds280353}
}
@article{fds280355,
Author = {Horisaki, R and Choi, K and Hahn, J and Tanida, J and Brady,
DJ},
Title = {Generalized sampling using a compound-eye imaging system for
multi-dimensional object acquisition.},
Journal = {Optics Express},
Volume = {18},
Number = {18},
Pages = {19367-19378},
Year = {2010},
Month = {August},
ISSN = {1094-4087},
url = {http://hdl.handle.net/10161/4241 Duke open
access},
Abstract = {In this paper, we propose generalized sampling approaches
for measuring a multi-dimensional object using a compact
compound-eye imaging system called thin observation module
by bound optics (TOMBO). This paper shows the proposed
system model, physical examples, and simulations to verify
TOMBO imaging using generalized sampling. In the system, an
object is modulated and multiplied by a weight distribution
with physical coding, and the coded optical signal is
integrated on to a detector array. A numerical estimation
algorithm employing a sparsity constraint is used for object
reconstruction.},
Doi = {10.1364/oe.18.019367},
Key = {fds280355}
}
@article{fds280354,
Author = {Cull, CF and Wikner, DA and Mait, JN and Mattheiss, M and Brady,
DJ},
Title = {Millimeter-wave compressive holography.},
Journal = {Applied Optics},
Volume = {49},
Number = {19},
Pages = {E67-E82},
Year = {2010},
Month = {July},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20648123},
Abstract = {We describe an active millimeter-wave holographic imaging
system that uses compressive measurements for
three-dimensional (3D) tomographic object estimation. Our
system records a two-dimensional (2D) digitized Gabor
hologram by translating a single pixel incoherent receiver.
Two approaches for compressive measurement are undertaken:
nonlinear inversion of a 2D Gabor hologram for 3D object
estimation and nonlinear inversion of a randomly subsampled
Gabor hologram for 3D object estimation. The object
estimation algorithm minimizes a convex quadratic problem
using total variation (TV) regularization for 3D object
estimation. We compare object reconstructions using linear
backpropagation and TV minimization, and we present
simulated and experimental reconstructions from both
compressive measurement strategies. In contrast with
backpropagation, which estimates the 3D electromagnetic
field, TV minimization estimates the 3D object that produces
the field. Despite undersampling, range resolution is
consistent with the extent of the 3D object band
volume.},
Doi = {10.1364/ao.49.000e67},
Key = {fds280354}
}
@article{fds280345,
Author = {Fernandez-Cull, C and Wikner, DA and Mattheiss, M and Mait, JN and Brady, D},
Title = {Sparse sampling and enhanced axial resolution in
millimeter-wave holographic imaging},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7670},
Publisher = {SPIE},
Year = {2010},
Month = {June},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.850404},
Abstract = {This paper describes an active millimeter-wave (MMW)
holographic imaging system used for the study of compressive
measurement for concealed weapons detection. We record a
digitized on-axis, Gabor hologram using a single pixel
incoherent receiver that is translated at the detector plane
to form an image composite. Capturing measurements in the
MMW regime can be costly since receiver circuits are
expensive and scanning systems can be plagued by their long
data acquisition times. Thus, we leverage recent advances in
compressive sensing with a traditional holographic method in
order to estimate a 3D (x,y,z) object distribution from a 2D
recorded image composite. To do this, we minimize a convex
quadratic function using total variation (TV)
regularization. Gabor holograms are recorded of
semi-transparent objects, in the MMW, mimicking weapons and
other objects. We present preliminary results of 3D
reconstructions of objects at various depths estimated from
a 2D recorded hologram. We compare backpropagation results
with our decompressive inference algorithm. A possible
application includes remote concealed weapons detection at
security checkpoints. © 2010 Copyright SPIE - The
International Society for Optical Engineering.},
Doi = {10.1117/12.850404},
Key = {fds280345}
}
@article{fds280350,
Author = {Xu, Q and Shi, K and Li, H and Choi, K and Horisaki, R and Brady, D and Psaltis, D and Liu, Z},
Title = {Inline holographic coherent anti-Stokes Raman
microscopy.},
Journal = {Optics Express},
Volume = {18},
Number = {8},
Pages = {8213-8219},
Year = {2010},
Month = {April},
ISSN = {1094-4087},
url = {http://hdl.handle.net/10161/4248 Duke open
access},
Abstract = {We demonstrate a simple approach for inline holographic
coherent anti-Stokes Raman scattering (CARS) microscopy, in
which a layer of uniform nonlinear medium is placed in front
of a specimen to be imaged. The reference wave created by
four-wave mixing in the nonlinear medium can interfere with
the CARS signal generated in the specimen to result in an
inline hologram. We experimentally and theoretically
investigate the inline CARS holography and show that it has
chemical selectivity and can allow for three-dimensional
imaging.},
Doi = {10.1364/oe.18.008213},
Key = {fds280350}
}
@article{fds280351,
Author = {Shankar, M and Pitsianis, NP and Brady, DJ},
Title = {Compressive video sensors using multichannel
imagers.},
Journal = {Applied Optics},
Volume = {49},
Number = {10},
Pages = {B9-17},
Year = {2010},
Month = {April},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20357845},
Abstract = {We explore the possibilities of obtaining compression in
video through modified sampling strategies using
multichannel imaging systems. The redundancies in video
streams are exploited through compressive sampling schemes
to achieve low power and low complexity video sensors. The
sampling strategies as well as the associated reconstruction
algorithms are discussed. These compressive sampling schemes
could be implemented in the focal plane readout hardware
resulting in drastic reduction in data bandwidth and
computational complexity.},
Doi = {10.1364/ao.49.0000b9},
Key = {fds280351}
}
@article{fds280352,
Author = {Cull, CF and Choi, K and Brady, DJ and Oliver, T},
Title = {Identification of fluorescent beads using a coded aperture
snapshot spectral imager.},
Journal = {Applied Optics},
Volume = {49},
Number = {10},
Pages = {B59-B70},
Year = {2010},
Month = {April},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20357842},
Abstract = {We apply a coded aperture snapshot spectral imager (CASSI)
to fluorescence microscopy. CASSI records a two-dimensional
(2D) spectrally filtered projection of a three-dimensional
(3D) spectral data cube. We minimize a convex quadratic
function with total variation (TV) constraints for data cube
estimation from the 2D snapshot. We adapt the TV
minimization algorithm for direct fluorescent bead
identification from CASSI measurements by combining a priori
knowledge of the spectra associated with each bead type. Our
proposed method creates a 2D bead identity image. Simulated
fluorescence CASSI measurements are used to evaluate the
behavior of the algorithm. We also record real CASSI
measurements of a ten bead type fluorescence scene and
create a 2D bead identity map. A baseline image from
filtered-array imaging system verifies CASSI's 2D bead
identity map.},
Doi = {10.1364/ao.49.000b59},
Key = {fds280352}
}
@article{fds280349,
Author = {Wagadarikar, AA and Marks, DL and Choi, K and Horisaki, R and Brady,
DJ},
Title = {Imaging through turbulence using compressive coherence
sensing.},
Journal = {Optics Letters},
Volume = {35},
Number = {6},
Pages = {838-840},
Year = {2010},
Month = {March},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20237616},
Abstract = {Previous studies have shown that the isoplanatic distortion
due to turbulence and the image of a remote object may be
jointly estimated from the 4D mutual intensity across an
aperture. This Letter shows that decompressive inference on
a 2D slice of the 4D mutual intensity, as measured by a
rotational shear interferometer, is sufficient for
estimation of sparse objects imaged through turbulence. The
2D slice is processed using an iterative algorithm that
alternates between estimating the sparse objects and
estimating the turbulence-induced phase screen. This
approach may enable new systems that infer object properties
through turbulence without exhaustive sampling of coherence
functions.},
Doi = {10.1364/ol.35.000838},
Key = {fds280349}
}
@article{fds280124,
Author = {Potuluri, P and Brady, DJ and Guenther, B and Cull, E and Qi, Y and Chapman, K},
Title = {Point of dispense drug verification using coded aperture
raman spectroscopy and image analysis},
Journal = {Optics Infobase Conference Papers},
Year = {2010},
Month = {January},
ISSN = {2162-2701},
url = {http://dx.doi.org/10.1364/aio.2010.atua2},
Abstract = {Coded aperture Raman spectroscopy enables standoff through
container classification of wide classes of dispensed
pharmaceuticals. Sensitivity relative to conventional Raman
systems is increased by nearly an order of magnitude,
enabling efficient integration in pharmacy workflow. © 2010
Optical Society of America.},
Doi = {10.1364/aio.2010.atua2},
Key = {fds280124}
}
@article{fds280177,
Author = {Potuluri, P and Brady, DJ and Guenther, B and Cull, E and Qi, Y and Chapman, K},
Title = {Point of dispense drug verification using coded aperture
raman spectroscopy and image analysis},
Journal = {Optics Infobase Conference Papers},
Year = {2010},
Month = {January},
ISSN = {2162-2701},
Abstract = {Coded aperture Raman spectroscopy enables standoff through
container classification of wide classes of dispensed
pharmaceuticals. Sensitivity relative to conventional Raman
systems is increased by nearly an order of magnitude,
enabling efficient integration in pharmacy workflow. © 2010
Optical Society of America.},
Key = {fds280177}
}
@article{fds280159,
Author = {Fernandez-Cull, C and Brady, D and Wikner, DA and Mait,
JN},
Title = {Millimeter-wave imaging using k-space compression},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {December},
ISSN = {2162-2701},
Abstract = {We apply compression in the spatial frequency domain to
generate millimeter wave images. Simulations indicate the
efficacy of the approach. We are in the process of testing
the system experimentally. © 2009 Optical Society of
America.},
Key = {fds280159}
}
@article{fds280160,
Author = {Wagadarikar, A and Marks, D and Choi, K and Brady,
D},
Title = {Compressive coherence sensing},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {December},
ISSN = {2162-2701},
Abstract = {The 4D cross spectral density function is recovered using 2D
rotational shear interferometer measurements and a matrix
completion algorithm for low rank matrices. Imaging of point
sources through turbulence is demonstrated. © 2009 Optical
Society of America.},
Key = {fds280160}
}
@article{fds280200,
Author = {Hagen, N and Brady, DJ},
Title = {Aberration correction in multiscale lenses},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {December},
Abstract = {Multiscale lens design splits the field into subregions and
attempts to correct the local wavefront error in each
subfield rather than the global error. We review the
aberration theory underlying the approach. © 2009 Optical
Society of America.},
Key = {fds280200}
}
@article{fds280201,
Author = {Brady, DJ},
Title = {Multiscale optical systems},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {December},
Abstract = {Cameras capturing gigapixel or even terapixel images are
enabled by lens systems combining single aperture objectives
with arrays of smaller scale processing optics. © 2009
Optical Society of America.},
Key = {fds280201}
}
@article{fds280217,
Author = {Lim, S and Horisaki, R and Choi, K and Marks, DL and Brady,
DJ},
Title = {Experimental demonstrations of compressive
holography},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {December},
Abstract = {We demonstrate 3D object reconstruction from a single 2D
data plane using compressive holography in Gabor and
Leith-Upatneiks geometries. © 2009 Optical Society of
America.},
Key = {fds280217}
}
@article{fds280218,
Author = {Choi, K and Horisaki, R and Marks, DL and Brady, DJ},
Title = {Coding and signal inference in compressive
holography},
Journal = {Optics Infobase Conference Papers},
Year = {2009},
Month = {December},
Abstract = {Compressive sensing enables highly accurate signal
reconstruction from fewer measurements than the number of
samples in a signal to be estimated. This paper describes a
theoretical framework for 3D tomographic reconstruction from
2D holographic measurements. © 2009 Optical Society of
America.},
Key = {fds280218}
}
@article{fds280338,
Author = {Marengo, EA and Zambrano-Nuñez, M and Brady, D},
Title = {Cramer-Rao study of one-dimensional scattering systems: Part
I: Formulation},
Journal = {Proceedings of the 6th Iasted International Conference on
Antennas, Radar, and Wave Propagation, Arp
2009},
Pages = {1-8},
Year = {2009},
Month = {December},
Abstract = {A Cramer-Rao bound (CRB) study is developed in
one-dimensional (1D) space which sheds fundamental insight
onto the information about multiply scattering point-like
scatterers that is contained in scattering field data
corresponding to transmissive, reflective, and combined
trans-missive plus reflective sensing geometries, and
single-and multi-frequency measurements.},
Key = {fds280338}
}
@article{fds280339,
Author = {Marengo, EA and Zambrano-Nuñez, M and Brady, D},
Title = {Cramer-Rao study of one-dimensional scattering systems: Part
II: Computer simulations},
Journal = {Proceedings of the 6th Iasted International Conference on
Antennas, Radar, and Wave Propagation, Arp
2009},
Pages = {9-13},
Year = {2009},
Month = {December},
Abstract = {This paper is the second of a two-part paper aimed at
studying fundamental limits in estimation in 1D scattering
systems via the Cramer-Rao bound. In this paper we provide
and discuss computer simulation results illustrating the
theory in the first paper.},
Key = {fds280339}
}
@article{fds280340,
Author = {Choi, K and Brady, DJ},
Title = {Coded aperture computed tomography},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7468},
Publisher = {SPIE},
Year = {2009},
Month = {December},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.825277},
Abstract = {Diverse physical measurements can be modeled by X-ray
transforms. While X-ray tomography is the canonical example,
reference structure tomography (RST) and coded aperture
snapshot spectral imaging (CASSI) are examples of physically
unrelated but mathematically equivalent sensor systems.
Historically, most x-ray transform based systems sample
continuous distributions and apply analytical inversion
processes. On the other hand, RST and CASSI generate
discrete multiplexed measurements implemented with coded
apertures. This multiplexing of coded measurements allows
for compression of measurements from a compressed sensing
perspective. Compressed sensing (CS) is a revelation that if
the object has a sparse representation in some basis, then a
certain number, but typically much less than what is
prescribed by Shannon's sampling rate, of random projections
captures enough information for a highly accurate
reconstruction of the object. This paper investigates the
role of coded apertures in x-ray transform measurement
systems (XTMs) in terms of data efficiency and
reconstruction fidelity from a CS perspective. To conduct
this, we construct a unified analysis using RST and CASSI
measurement models. Also, we propose a novel compressive
x-ray tomography measurement scheme which also exploits
coding and multiplexing, and hence shares the analysis of
the other two XTMs. Using this analysis, we perform a
qualitative study on how coded apertures can be exploited to
implement physical random projections by "regularizing" the
measurement systems. Numerical studies and simulation
results demonstrate several examples of the impact of
coding. © 2009 SPIE.},
Doi = {10.1117/12.825277},
Key = {fds280340}
}
@article{fds330742,
Author = {Feigin, J and Brady, D},
Title = {Joint transmitter/receiver I/Q imbalance compensation for
direct conversion OFDM in packet-switched multipath
environments},
Journal = {Ieee Transactions on Signal Processing},
Volume = {57},
Number = {11},
Pages = {4588-4593},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {November},
url = {http://dx.doi.org/10.1109/TSP.2009.2024999},
Abstract = {This correspondence presents an algorithm for compensation
of I/Q imbalance for a direct-conversion packet-switched
orthogonal frequency-division-multiplexing (OFDM)
communications system, which accounts for transmitter I/Q
imbalance, receiver I/Q imbalance, phase/ frequency error,
and dispersive multipath fading. The proposed estimation
algorithm is then presented, which operates within the
framework of existing multiuser OFDM radio standards
(802.11a). It is shown that this algorithm accurately
estimates and corrects transceiver I/Q imbalance on a
packet-by-packet basis, all within the receiver's digital
baseband. © 2009 IEEE.},
Doi = {10.1109/TSP.2009.2024999},
Key = {fds330742}
}
@article{fds330741,
Author = {Valchev, DG and Brady, D},
Title = {Three-dimensional multipath shape factors for spatial
modeling of wireless channels},
Journal = {Ieee Transactions on Wireless Communications},
Volume = {8},
Number = {11},
Pages = {5542-5551},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {November},
url = {http://dx.doi.org/10.1109/TWC.2009.080988},
Abstract = {This paper develops a generalized theory of multipath shape
factors used to study the small-scale fading statistics in
three-dimensional non-omnidirectional multipath channels.
Previous results for horizontal propagation channels are
special cases of the present framework when the multipath
angular power density (APD) and the travel direction of the
mobile unit are confined to a plane. The three-dimensional
multipath shape factors are derived in terms of the first
three degrees of unnormalized spherical harmonics of the
APD. Based on the so derived shape factors, analytical
expressions for the level crossing rate, average fade
duration and approximate envelope correlation are derived
for a Rayleigh fading three-dimensional channel. © 2009
IEEE.},
Doi = {10.1109/TWC.2009.080988},
Key = {fds330741}
}
@booklet{Mahalanobis09,
Author = {Mahalanobis, A and Neifeld, M and Bhagavatula, VK and Haberfelde, T and Brady, D},
Title = {Off-axis sparse aperture imaging using phase optimization
techniques for application in wide-area imaging
systems.},
Journal = {Applied Optics},
Volume = {48},
Number = {28},
Pages = {5212-5224},
Year = {2009},
Month = {October},
ISSN = {1559-128X},
url = {http://dx.doi.org/10.1364/ao.48.005212},
Abstract = {Sparse apertures find imaging applications in diverse fields
such as astronomy and medicine. We are motivated by the
design of a wide-area imaging system where sparse apertures
can be used to construct novel and efficient optical
designs. Specifically, we investigate the use of sparse
apertures for off-axis imaging at infrared wavelengths while
combating the effects of chromaticity to preserve
resolution. In principle, several such sparse apertures can
be interleaved within a common aperture to simultaneously
image in multiple directions. This can ultimately lead to
the design of wide-area imaging systems that require
considerably less optical and electronic hardware. The
resolution achievable using a sparse aperture is the same as
that of a fully open aperture. In the case of off-axis
imaging, however, the point spread function (PSF) introduces
a blur due to chromaticity that degrades the resolution of
the system. Of course, the blur can be eliminated by imaging
at a single wavelength. However the signal-to-noise ratio
(SNR) is poor, which ultimately degrades image quality. To
improve SNR, it is necessary to widen the band of
wavelengths, which of course degrades resolution due to
chromaticity. Hence there is a fundamental trade between the
SNR and the resolution as a function of bandwidth. We show
that by using a combination of microprisms and phase
optimized micropistons it is possible to reduce the
chromatic blur over a band of wavelengths and improve the
PSF considerably to restore the resolution of the image. The
concepts are validated by means of simulations and verified
with experimental data to demonstrate the advantages of
phase optimized micropistons in off-axis sparse aperture
imaging systems.},
Doi = {10.1364/ao.48.005212},
Key = {Mahalanobis09}
}
@article{fds280337,
Author = {Hagen, N and Brady, DJ},
Title = {Coded aperture DUV spectrometer for standoff Raman
spectroscopy},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7319},
Publisher = {SPIE},
Year = {2009},
Month = {September},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.818830},
Abstract = {We have designed and constructed a coded aperture
spectrometer for use in the deep UV range. The Czerny-
Turner design provides sufficient spectral resolution to
observe Raman scattering features, while the use of a coded
aperture provides a greatly improved light collection
efficiency for scattering sources. The resulting instrument
is capable of analyzing Raman spectra from samples at a 1
meter viewing distance. We provide an overview of the
system, its optical design, and some preliminary
measurements. © 2009 SPIE.},
Doi = {10.1117/12.818830},
Key = {fds280337}
}
@article{fds280123,
Author = {Brady, D},
Title = {Rich Democracies, Poor People: How Politics Explain
Poverty},
Journal = {Rich Democracies, Poor People: How Politics Explain
Poverty},
Pages = {1-264},
Publisher = {Oxford University Press},
Year = {2009},
Month = {September},
url = {http://dx.doi.org/10.1093/acprof:oso/9780195385878.001.0001},
Abstract = {This book advances a political argument for poverty. This
argument is developed from explaining cross-national and
historical variation in poverty across affluent democracies
since the late 1960s. Specifically, institutionalized power
relations theory is proposed as an explanation to counter
the individualism that prevails in contemporary poverty
scholarship. The book also develops arguments for how
poverty should be conceptualized and measured, and offers a
comprehensive study of poverty in affluent democracies. A
variety of analyses are conduced to explain variation in
poverty and to represent institutionalized power relations,
liberal economic, and structural theories of poverty.
Ultimately, the welfare state and Leftist politics emerge as
the most influential forces on poverty. The book contends
that poverty scholarship should focus less on the individual
characteristics of the poor and more on the politics of
poverty and equality. Rather than viewing poverty as the
unfortunate by-product of labor markets or demography,
poverty should be understood as a result of the power
relations of collective political actors and the extent to
which egalitarianism is institutionalized in the welfare
state.},
Doi = {10.1093/acprof:oso/9780195385878.001.0001},
Key = {fds280123}
}
@article{fds330743,
Author = {Valchev, DG and Brady, D},
Title = {Multipath directivity and spatial selectivity in
three-dimensional wireless channels},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {57},
Number = {7},
Pages = {2147-2154},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {August},
url = {http://dx.doi.org/10.1109/TAP.2009.2021873},
Abstract = {A generalized definition is presented of multipath angular
spread, used to study the spatial correlation of the signal
envelope in a three-dimensional wireless channel, both in
the cases of a three-dimensional and a horizontal travel
direction. Previous results from two-dimensional modeling
are shown to be a special case of this general analysis when
the multipath power and the travel direction are confined to
a single plane in space. The results show that the main lobe
of the spatial correlation of the signal envelope at a given
distance has an approximately Gaussian dependence on the
three-dimensional multipath directivity metric proposed in
this paper, for both cases for the travel direction. © 2009
IEEE.},
Doi = {10.1109/TAP.2009.2021873},
Key = {fds330743}
}
@article{fds280343,
Author = {Brady, DJ and Choi, K and Marks, DL and Horisaki, R and Lim,
S},
Title = {Compressive holography.},
Journal = {Optics Express},
Volume = {17},
Number = {15},
Pages = {13040-13049},
Year = {2009},
Month = {July},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19654708},
Abstract = {Compressive sampling enables signal reconstruction using
less than one measurement per reconstructed signal value.
Compressive measurement is particularly useful in generating
multidimensional images from lower dimensional data. We
demonstrate single frame 3D tomography from 2D holographic
data.},
Doi = {10.1364/oe.17.013040},
Key = {fds280343}
}
@article{fds280336,
Author = {Fernandez, CA and Wagadarikar, A and Brady, DJ and McCain, SC and Oliver, T},
Title = {Fluorescence microscopy with a coded aperture snapshot
spectral imager},
Journal = {Progress in Biomedical Optics and Imaging Proceedings of
Spie},
Volume = {7184},
Publisher = {SPIE},
Year = {2009},
Month = {June},
ISSN = {1605-7422},
url = {http://dx.doi.org/10.1117/12.807863},
Abstract = {This paper describes the application of a dual-dispersive
(DD) coded aperture snapshot spectral imager (CASSI) to
fluorescence microscopy. CASSI records an interleaved
spatially varying, spectrally filtered map of an object onto
a two-dimensional (2D) focal plane. Using a compressive
sensing framework, the spectrally encoded 2D scene is
reconstructed into a three-dimensional (3D) data cube. CASSI
also records a 3D dataset at video rate - making it suitable
for dynamic cellular imaging. A convex optimization
technique combining least squares QR factorization with a
total variance constraint is used to reconstruct the image.
The system records 32 spectral channels that span the
spectral range between 450nm and 750nm with 10nm spectral
resolution for any pixel in a 2D image. This paper
illustrates the application of CASSI imaging to fluorescence
microscopy applications. We report on the reconstruction of
fluorescent microspheres used in fluorescence microscopy as
calibration standards. Images are compared with a
multi-spectral confocal system. ©2009 SPIE.},
Doi = {10.1117/12.807863},
Key = {fds280336}
}
@article{fds280342,
Author = {Brady, DJ and Hagen, N},
Title = {Multiscale lens design.},
Journal = {Optics Express},
Volume = {17},
Number = {13},
Pages = {10659-10674},
Year = {2009},
Month = {June},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19550462},
Abstract = {While lenses of aperture less than 1000lambda frequently
form images with pixel counts approaching the
space-bandwidth limit, only heroic designs approach the
theoretical information capacity at larger scales. We
propose to use the field processing capabilities of
small-scale secondary lens arrays to correct aberrations due
to larger scale objective lenses, with an ultimate goal of
achieving diffraction-limited imaging for apertures greater
than 10,000lambda .We present an example optical design
using an 8 mm entrance pupil capable of resolving 20
megapixels.},
Doi = {10.1364/oe.17.010659},
Key = {fds280342}
}
@article{fds280334,
Author = {Portnoy, AD and Brady, DJ},
Title = {Resolution and interpolation of multichannel long wave
infrared camera data},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7246},
Publisher = {SPIE},
Year = {2009},
Month = {May},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.807969},
Abstract = {We evaluate the performance of a multiple aperture camera
with a target projector testbed and compare it to a single
lens LWIR camera with a similar field of view and pixel
count. We measure a noise equivalent temperature difierence
of 131 mK for the multiple aperture camera and 121 mK for
the conventional camera which uses similar uncooled 25 μm
pixel technology. Spatial frequency response is analyzed
using a collection of 4-bar targets with different periods.
After characterization, we remove aliasing from the multiple
aperture data to resolve targets as high as 0.192 cy/mrad.
© 2009 SPIE.},
Doi = {10.1117/12.807969},
Key = {fds280334}
}
@article{fds280341,
Author = {Wagadarikar, AA and Pitsianis, NP and Sun, X and Brady,
DJ},
Title = {Video rate spectral imaging using a coded aperture snapshot
spectral imager.},
Journal = {Optics Express},
Volume = {17},
Number = {8},
Pages = {6368-6388},
Year = {2009},
Month = {April},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19365462},
Abstract = {We have previously reported on coded aperture snapshot
spectral imagers (CASSI) that can capture a full frame
spectral image in a snapshot. Here we describe the use of
CASSI for spectral imaging of a dynamic scene at video rate.
We describe significant advances in the design of the
optical system, system calibration procedures and
reconstruction method. The new optical system uses a double
Amici prism to achieve an in-line, direct view
configuration, resulting in a substantial improvement in
image quality. We describe NeAREst, an algorithm for
estimating the instantaneous three-dimensional
spatio-spectral data cube from CASSI's two-dimensional array
of encoded and compressed measurements. We utilize CASSI's
snapshot ability to demonstrate a spectral image video of
multi-colored candles with live flames captured at 30 frames
per second.},
Doi = {10.1364/oe.17.006368},
Key = {fds280341}
}
@booklet{Portnoy09,
Author = {Portnoy, A and Pitsianis, N and Sun, X and Brady, D and Gibbons, R and Silver, A and Te Kolste and R and Chen, C and Dillon, T and Prather,
D},
Title = {Design and characterization of thin multiple aperture
infrared cameras.},
Journal = {Applied Optics},
Volume = {48},
Number = {11},
Pages = {2115-2126},
Year = {2009},
Month = {April},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19363550},
Abstract = {We describe a multiple-aperture long-wave infrared camera
built on an uncooled microbolometer array with the objective
of decreasing camera thickness. The 5 mm thick optical
system is an f/1.2 design with a 6.15 mm effective focal
length. An integrated image is formed from the subapertures
using correlation-based registration and a least gradient
reconstruction algorithm. We measure a 131 mK NETD. The
system's spatial frequency is analyzed with 4 bar targets.
With proper calibration, our multichannel interpolation
results recover contrast for targets at frequencies beyond
the aliasing limit of the individual subimages.},
Doi = {10.1364/ao.48.002115},
Key = {Portnoy09}
}
@article{fds280335,
Author = {Zheng, N and Hagen, N and John, R and Brady, DJ},
Title = {A static multiplex Fabry-Perot spectrometer},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7249},
Publisher = {SPIE},
Year = {2009},
Month = {March},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.805663},
Abstract = {We demonstrate a static multiplex spectrometer based on a
Fabry-Perot interferometric filter for measuring the mean
spectral content of diffuse sources. By replacing the slit
of a low-dispersion grating spectrometer with a Fabry-Perot
interferometric filter, we improve the resolving power of
the instrument while simultaneously overcoming the free
spectral range limitation of the Fabry Perot. The resulting
instrument is smaller than conventional spectrometers having
the same resolving power. We present experimental results
from the spectrometer using neon lamp, He-Ne laser, and
diode laser sources over a wavelength range from 620 nm to
660 nm. © 2009 SPIE-IS&T.},
Doi = {10.1117/12.805663},
Key = {fds280335}
}
@booklet{Uttam09,
Author = {Uttam, S and Goodman, NA and Neifeld, MA and Kim, C and John, R and Kim, J and Brady, D},
Title = {Optically multiplexed imaging with superposition space
tracking},
Journal = {Optics Express},
Volume = {17},
Number = {3},
Pages = {1691-1713},
Year = {2009},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/OE.17.001691},
Abstract = {We describe a novel method to track targets in a large field
of view. This method simultaneously images multiple, encoded
sub-fields of view onto a common focal plane. Sub-field
encoding enables target tracking by creating a unique
connection between target characteristics in superposition
space and the target's true position in real space. This is
accomplished without reconstructing a conventional image of
the large field of view. Potential encoding schemes include
spatial shift, rotation, and magnification. We discuss each
of these encoding schemes, but the main emphasis of the
paper and all examples are based on one-dimensional spatial
shift encoding. System performance is evaluated in terms of
two criteria: average decoding time and probability of
decoding error. We study these performance criteria as a
function of resolution in the encoding scheme and
signal-to-noise ratio. Finally, we include simulation and
experimental results demonstrating our novel tracking
method. © 2009 Optical Society of America.},
Doi = {10.1364/OE.17.001691},
Key = {Uttam09}
}
@article{fds280323,
Author = {Wagadarikar, AA and Pitsianis, NP and Sun, X and Brady,
DJ},
Title = {Spectral image estimation for coded aperture snapshot
spectral imagers},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7076},
Publisher = {SPIE},
Year = {2008},
Month = {December},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.795545},
Abstract = {This paper describes numerical estimation techniques for
coded aperture snapshot spectral imagers (CASSI). In a
snapshot, a CASSI captures a two-dimensional (2D) array of
measurements that is an encoded representation of both
spectral information and 2D spatial information of a scene.
The spatial information is modulated by a coded aperture and
the spectral information is modulated by a dispersive
element. The estimation process decodes the 2D measurements
to render a three-dimensional spatio-spectral estimate of
the scene, and is therefore an indispensable component of
the spectral imager. Numerical estimation results are
presented.},
Doi = {10.1117/12.795545},
Key = {fds280323}
}
@article{fds280324,
Author = {Shankar, M and Pitsianis, NP and Brady, D},
Title = {Spatio-temporal sampling for video},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7076},
Publisher = {SPIE},
Year = {2008},
Month = {December},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.795753},
Abstract = {With this work we propose spatio-temporal sampling
strategies for video using a lenslet array computational
imaging system and explore the opportunities and challenges
in the design of compressive video sensors and corresponding
processing algorithms. The redundancies in video streams are
exploited by (a) sampling the sub-apertures of a
multichannel (TOMBO) camera, and (b) by the computational
reconstruction to achieve low power and low complexity video
sensors. A spatial and a spatio-temporal sampling strategy
are considered, taking into account the feasibility for
implementation in the focal-plane readout hardware. The
algorithms used to reconstruct the video frames from
measurements are also presented.},
Doi = {10.1117/12.795753},
Key = {fds280324}
}
@article{fds280333,
Author = {Marcia, RF and Kim, C and Eldeniz, C and Kim, J and Brady, DJ and Willett,
RM},
Title = {Superimposed video disambiguation for increased field of
view.},
Journal = {Optics Express},
Volume = {16},
Number = {21},
Pages = {16352-16363},
Year = {2008},
Month = {October},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18852741},
Abstract = {Many infrared optical systems in wide-ranging applications
such as surveillance and security frequently require large
fields of view (FOVs). Often this necessitates a focal plane
array (FPA) with a large number of pixels, which, in
general, is very expensive. In a previous paper, we proposed
a method for increasing the FOV without increasing the pixel
resolution of the FPA by superimposing multiple sub-images
within a static scene and disambiguating the observed data
to reconstruct the original scene. This technique, in
effect, allows each sub-image of the scene to share a single
FPA, thereby increasing the FOV without compromising
resolution. In this paper, we demonstrate the increase of
FOVs in a realistic setting by physically generating a
superimposed video from a single scene using an optical
system employing a beamsplitter and a movable mirror.
Without prior knowledge of the contents of the scene, we are
able to disambiguate the two sub-images, successfully
capturing both large-scale features and fine details in each
sub-image. We improve upon our previous reconstruction
approach by allowing each sub-image to have slowly changing
components, carefully exploiting correlations between
sequential video frames to achieve small mean errors and to
reduce run times. We show the effectiveness of this improved
approach by reconstructing the constituent images of a
surveillance camera video.},
Doi = {10.1364/oe.16.016352},
Key = {fds280333}
}
@article{fds280260,
Author = {Brady, DJ},
Title = {Optical Imaging and Spectroscopy},
Journal = {Optical Imaging and Spectroscopy},
Pages = {1-510},
Publisher = {JOHN WILEY & SONS INC},
Year = {2008},
Month = {August},
url = {http://dx.doi.org/10.1002/9780470443736},
Abstract = {An essential reference for optical sensor system design This
is the first text to present an integrated view of the
optical and mathematical analysis tools necessary to
understand computational optical system design. It presents
the foundations of computational optical sensor design with
a focus entirely on digital imaging and spectroscopy. It
systematically covers: Coded aperture and tomographic
imaging Sampling and transformations in optical systems,
including wavelets and generalized sampling techniques
essential to digital system analysis Geometric, wave, and
statistical models of optical fields The basic function of
modern optical detectors and focal plane arrays Practical
strategies for coherence measurement in imaging system
design The sampling theory of digital imaging and
spectroscopy for both conventional and emerging compressive
and generalized measurement strategies Measurement code
design Linear and nonlinear signal estimation The book
concludes with a review of numerous design strategies in
spectroscopy and imaging and clearly outlines the benefits
and limits of each approach, including coded aperture and
imaging spectroscopy, resonant and filter-based systems, and
integrated design strategies to improve image resolution,
depth of field, and field of view. Optical Imaging and
Spectroscopy is an indispensable textbook for advanced
undergraduate and graduate courses in optical sensor design.
In addition to its direct applicability to optical system
design, unique perspectives on computational sensor design
presented in the text will be of interest for sensor
designers in radio and millimeter wave, X-ray, and acoustic
systems. © 2009 John Wiley & Sons, Inc.},
Doi = {10.1002/9780470443736},
Key = {fds280260}
}
@article{fds280331,
Author = {McCain, ST and Willett, RM and Brady, DJ},
Title = {Multi-excitation Raman spectroscopy technique for
fluorescence rejection.},
Journal = {Optics Express},
Volume = {16},
Number = {15},
Pages = {10975-10991},
Year = {2008},
Month = {July},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18648412},
Abstract = {Multi-excitation Raman spectroscopy filters out Raman
signals from a fluorescent background by sequentially using
multiple excitation frequencies. The filtering method
exploits the shift of the Raman spectra with excitation
frequency and the static response of the fluorescent
background. This technique builds upon previous work which
used two slightly shifted excitations, Shifted Excitation
Raman Difference Spectroscopy (SERDS), in order to filter
the Raman signal. An Expectation-Maximization algorithm is
used to estimate the Raman and fluorescence signals from
multiple spectra acquired with slightly shifted excitation
frequencies. In both simulation and experiment, the efficacy
of the algorithm increases with the number of excitation
frequencies even when holding the total excitation energy
constant, such that the signal to noise ratio is inversely
proportional to the number of excitation frequencies. In
situations where the intense fluorescence causes significant
shot noise compared to the weak Raman signals, the
multi-excitation approach is more effective than
non-iterative techniques such as polynomial background
subtraction.},
Doi = {10.1364/oe.16.010975},
Key = {fds280331}
}
@article{fds280332,
Author = {Gehm, ME and Kim, MS and Fernandez, C and Brady, DJ},
Title = {High-throughput, multiplexed pushbroom hyperspectral
microscopy.},
Journal = {Optics Express},
Volume = {16},
Number = {15},
Pages = {11032-11043},
Year = {2008},
Month = {July},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.16.011032},
Abstract = {We describe a high-throughput hyperspectral microscope. The
system replaces the slit of conventional pushbroom spectral
imagers with a static coded aperture mask. We present the
theoretical underpinnings of the aperture coded spectral
engine and describe two proof-of-concept experimental
implementations. Compared to a conventional pushbroom
system, the aperture coded systems have 32 times greater
throughput. Both systems have about a 1 nm spectral
resolution over the spectral range of 550-665 nm. For the
first design, the spatial resolution for the system is 5.4
microm while the spatial resolution for the second system
ranges from 7.7 microm to 1.54 microm. We describe
experimental results from proof-of-concept applications of
the imager to hyperspectral microscopy.},
Doi = {10.1364/oe.16.011032},
Key = {fds280332}
}
@article{fds280328,
Author = {Portnoy, AD and Pitsianis, NP and Sun, X and Brady,
DJ},
Title = {Multichannel sampling schemes for optical imaging
systems.},
Journal = {Applied Optics},
Volume = {47},
Number = {10},
Pages = {B76-B85},
Year = {2008},
Month = {April},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18382553},
Abstract = {We introduce a framework of focal-plane coding schemes for
multichannel sampling in optical systems. A particular
objective is to develop an ultrathin imager without
compromising image resolution. We present a complete f/2.1
optical system with a thickness of 2.2 mm. The resolution is
maintained in the thin optical system by an integrated
design of the encoding scheme, the process of making the
coding elements, and the decoding algorithms.},
Doi = {10.1364/ao.47.000b76},
Key = {fds280328}
}
@article{fds280329,
Author = {Tumbar, R and Marks, DL and Brady, DJ},
Title = {Robust, common path, phase shifting interferometer and
optical profilometer.},
Journal = {Applied Optics},
Volume = {47},
Number = {10},
Pages = {B32-B43},
Year = {2008},
Month = {April},
ISSN = {1559-128X},
url = {http://dx.doi.org/10.1364/ao.47.000b32},
Abstract = {We describe an improved implementation of our previously
reported common-path, phase shifting, and shearing
interferometer. Using a time-multiplexed phase shifting
scheme, we demonstrate higher sampling resolution, better
light sensitivity, and use of arbitrary phase shifting
algorithms. We describe microscopic imaging of the surface
profile of a copper-plated silicon wafer and demonstrate
that the system is vibration insensitive with approximately
lambda/100 repeatability. In a more general discussion of
our method, we describe the different functional elements
and suggest alternative designs and improvements. Possible
uses include full-field coherent imaging and high dynamic
range wavefront sensing, which we briefly
discuss.},
Doi = {10.1364/ao.47.000b32},
Key = {fds280329}
}
@article{fds280330,
Author = {Brady, DJ and Dogariu, A and Fiddy, MA and Mahalanobis,
A},
Title = {Computational optical sensing and imaging: introduction to
the feature issue.},
Journal = {Applied Optics},
Volume = {47},
Number = {10},
Pages = {COSI1-COSI2},
Year = {2008},
Month = {April},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18382555},
Doi = {10.1364/ao.47.0cosi1},
Key = {fds280330}
}
@booklet{Shankar08,
Author = {Shankar, M and Willett, R and Pitsianis, N and Schulz, T and Gibbons, R and Te Kolste and R and Carriere, J and Chen, C and Prather, D and Brady,
D},
Title = {Thin infrared imaging systems through multichannel
sampling.},
Journal = {Applied Optics},
Volume = {47},
Number = {10},
Pages = {B1-10},
Year = {2008},
Month = {April},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18382544},
Abstract = {The size of infrared camera systems can be reduced by
collecting low-resolution images in parallel with multiple
narrow-aperture lenses rather than collecting a single
high-resolution image with one wide-aperture lens. We
describe an infrared imaging system that uses a
three-by-three lenslet array with an optical system length
of 2.3 mm and achieves Rayleigh criteria resolution
comparable with a conventional single-lens system with an
optical system length of 26 mm. The high-resolution final
image generated by this system is reconstructed from the
low-resolution images gathered by each lenslet. This is
accomplished using superresolution reconstruction algorithms
based on linear and nonlinear interpolation algorithms. Two
implementations of the ultrathin camera are demonstrated and
their performances are compared with that of a conventional
infrared camera.},
Doi = {10.1364/ao.47.0000b1},
Key = {Shankar08}
}
@booklet{Wagadarikar08,
Author = {Wagadarikar, A and John, R and Willett, R and Brady,
D},
Title = {Single disperser design for coded aperture snapshot spectral
imaging.},
Journal = {Applied Optics},
Volume = {47},
Number = {10},
Pages = {B44-B51},
Year = {2008},
Month = {April},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18382550},
Abstract = {We present a single disperser spectral imager that exploits
recent theoretical work in the area of compressed sensing to
achieve snapshot spectral imaging. An experimental prototype
is used to capture the spatiospectral information of a scene
that consists of two balls illuminated by different light
sources. An iterative algorithm is used to reconstruct the
data cube. The average spectral resolution is 3.6 nm per
spectral channel. The accuracy of the instrument is
demonstrated by comparison of the spectra acquired with the
proposed system with the spectra acquired by a nonimaging
reference spectrometer.},
Doi = {10.1364/ao.47.000b44},
Key = {Wagadarikar08}
}
@article{fds280199,
Author = {Portnoy, AD and Brady, DJ},
Title = {Quantitative performance metrics with long wave infrared
multiple aperture cameras},
Journal = {Optics Infobase Conference Papers},
Year = {2008},
Month = {January},
Abstract = {We characterize a long wave infrared multiple aperture
imaging system by experimentally measuring its Noise
Equivalent Temperature Difference and modulation transfer
function. These results are compared with a conventional
system. © 2008 Optical Society of America.},
Key = {fds280199}
}
@article{fds280270,
Author = {Fernandez, C and Lim, S and Guenther, BD and Brady, DJ and McCain,
ST},
Title = {High-throughput, multiplex aperture-coded raman spectrometer
for biomedical diagnostics},
Journal = {Biomedical Optics, Biomed 2008},
Pages = {BTuF15},
Year = {2008},
Month = {January},
url = {http://dx.doi.org/10.1364/biomed.2008.btuf15},
Abstract = {Over the past couple of years, we have developed an aperture
coded Raman spectrometer whose performance is optimized for
extended, incoherent sources. We describe results conveying
the potential for in vivo biomedical diagnostics. ©2007
Optical Society of America.},
Doi = {10.1364/biomed.2008.btuf15},
Key = {fds280270}
}
@article{fds280321,
Author = {Badieirostami, M and Momtahan, O and Hsieh, C and Adibi, A and Brady,
DJ},
Title = {Very-high-resolution tandem Fabry-Perot etalon cylindrical
beam volume hologram spectrometer for diffuse source
spectroscopy.},
Journal = {Optics Letters},
Volume = {33},
Number = {1},
Pages = {31-33},
Year = {2008},
Month = {January},
ISSN = {0146-9592},
url = {http://dx.doi.org/10.1364/ol.33.000031},
Abstract = {We demonstrate a compact and slitless spectrometer with high
resolution formed by cascading a Fabry-Perot etalon (FPE)
and a cylindrical beam volume hologram (CBVH). The most
significant advantage of this combined spectrometer is that
we can independently encode spectral information of a
diffuse beam in a 2D plane. Also, we show that in this
slitless configuration we can simultaneously benefit from
the advantages of both elements: the high resolution of the
FPE and the large spectral range of the CBVH. Here, we
report on the experimental demonstration of a spectrometer
with better than 0.2 nm resolution.},
Doi = {10.1364/ol.33.000031},
Key = {fds280321}
}
@article{fds280326,
Author = {Healy, D and Brady, DJ},
Title = {Compression at the physical interface: The A-to-I and
MONTAGE programs},
Journal = {Ieee Signal Processing Magazine},
Volume = {25},
Number = {2},
Pages = {67-71},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2008},
Month = {January},
ISSN = {1053-5888},
url = {http://dx.doi.org/10.1109/MSP.2007.914996},
Abstract = {Progresses in physical compressive sampling under the
Defense Advanced Research Agency's Analog-to-Information
(A-to-I) and Multiple Optical Non-Redundant Aperture
Generalized Sensors (MONTAGE) programs are more about
finding aggressive forms of generalized sampling under which
measurements consist of transformation, projections or
encodings of the signal onto discrete digital data. The two
projects differ in that the former seeks to revolutionize
very high temporal bandwidth analog to digital signal
conversion whereas the latter aims to revolutionize very
high spatial bandwidth analog to digital signal conversion.
Nevertheless, MONTAGE focuses on data conversion approaches
while both have realized new opportunities and established
various important bounds on the sampling required as a
function of prior and ancillary information.},
Doi = {10.1109/MSP.2007.914996},
Key = {fds280326}
}
@article{fds280327,
Author = {Athale, R and Healy, DM and Brady, DJ and Neifeld,
MA},
Title = {Reinventing the camera},
Journal = {Optics and Photonics News},
Volume = {19},
Number = {3},
Pages = {32-37},
Publisher = {The Optical Society},
Year = {2008},
Month = {January},
ISSN = {1047-6938},
url = {http://dx.doi.org/10.1364/OPN.19.3.000032},
Abstract = {The workshop for the Microsystems Technology Office at the
Defense Advanced Research Projects Agency (DARPA), 'Camera
Ab Initio', in April, 2003 challenged the attendees to
rethink the architecture of a camera, or an imaging sensor.
The workshop resulted in the MONTAGE (Multiple Nonredundant
Optical Aperture generalized Imager) project, through which
DARPA has successfully demonstrated that thin imaging
systems based on multichannel and folded path optics could
produce high-quality images. The project was based on two
principles, imaging systems are inherently low-pass filters
with spatial bandwidth proportional to the extent of the
aperture, and optical power collection efficiency is
proportional to aperture area. Ideal design strategies will
integrate MONTAGE optics with co-designed focal planes and
read-out circuits. MONTAGE has focused nearly exclusively on
joint optimization of optical systems and computational
post-processing.},
Doi = {10.1364/OPN.19.3.000032},
Key = {fds280327}
}
@article{fds280325,
Author = {Marcia, RF and Kim, C and Kim, J and Brady, DJ and Willett,
RM},
Title = {Fast disambiguation of superimposed images for increased
field of view},
Journal = {Proceedings International Conference on Image Processing,
Icip},
Pages = {2620-2623},
Publisher = {IEEE},
Year = {2008},
ISSN = {1522-4880},
url = {http://dx.doi.org/10.1109/ICIP.2008.4712331},
Abstract = {Many infrared optical systems in wide-ranging applications
such as surveillance and security frequently require large
fields of view. Often this necessitates a focal plane array
(FPA) with a large number of pixels, which, in general, is
very expensive. In this paper, we propose a method for
increasing the field of view without increasing the pixel
resolution of the FPA by superimposing the multiple
subimages within a scene and disambiguating the observed
data to reconstruct the original scene. This technique, in
effect, allows each subimage of the scene to share a single
FPA, thereby increasing the field of view without
compromising resolution. To disambiguate the subimages, we
develop wavelet regularized reconstruction methods which
encourage sparsity in the solution. We present results from
numerical experiments that demonstrate the effectiveness of
this approach. © 2008 IEEE.},
Doi = {10.1109/ICIP.2008.4712331},
Key = {fds280325}
}
@article{fds319897,
Author = {Uttam, S and Goodman, NA and Neifeld, MA and Changsoon, K and Jungsang,
K and Brady, DJ},
Title = {Optically multiplexed imaging with superposition space
tracking},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {7096},
Year = {2008},
url = {http://dx.doi.org/10.1117/12.795150},
Abstract = {We describe a novel method to track targets in a large field
of view. This method simultaneously images multiple, encoded
sub-fields of view onto a common focal plane. Sub-field
encoding enables target tracking by creating a unique
connection between target characteristics in superposition
space and the target's true position in real space. This is
accomplished without reconstructing a conventional image of
the large field of view. Potential encoding schemes include
spatial shift, rotation, and magnification. We briefly
discuss each of these encoding schemes, but the main
emphasis of the paper and all examples are based on
one-dimensional spatial shift encoding. Simulation results
are included to show the efficacy of the proposed sub-field
encoding scheme.},
Doi = {10.1117/12.795150},
Key = {fds319897}
}
@article{fds280315,
Author = {Mahalanobis, A and Reyner, C and Patel, H and Haberfelde, T and Brady,
D and Neifeld, M and Kumar, BVKV and Rogers, S},
Title = {IR performance study of an adaptive coded aperture
"diffractive imaging" system employing MEMS "eyelid shutter"
technologies},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6714},
Publisher = {SPIE},
Year = {2007},
Month = {December},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.745956},
Abstract = {Adaptive coded aperture sensing is an emerging technology
enabling real time, wide-area IR/visible sensing and
imaging. Exploiting unique imaging architectures, adaptive
coded aperture sensors achieve wide field of view,
near-instantaneous optical path repositioning, and high
resolution while reducing weight, power consumption and cost
of air- and space born sensors. Such sensors may be used for
military, civilian, or commercial applications in all
optical bands but there is special interest in diffraction
imaging sensors for IR applications. Extension of coded
apertures from Visible to the MWIR introduces the effects of
diffraction and other distortions not observed in shorter
wavelength systems. A new approach is being developed under
the DARPA/SPO funded LACOSTE (Large Area Coverage Optical
search-while Track and Engage) program, that addresses the
effects of diffraction while gaining the benefits of coded
apertures, thus providing flexibility to vary resolution,
possess sufficient light gathering power, and achieve a wide
field of view (WFOV). The photonic MEMS-Eyelid
"sub-aperture" array technology is currently being
instantiated in this DARPA program to be the heart of
conducting the flow (heartbeat) of the incoming signal.
However, packaging and scalability are critical factors for
the MEMS "sub-aperture"" technology which will determine
system efficacy as well as military and commercial
usefulness. As larger arrays with 1,000,000+ sub-apertures
are produced for this LACOSTE effort, the available Degrees
of Freedom (DOF) will enable better spatial resolution,
control and refinement on the coding for the system. Studies
(SNR simulations) will be performed (based on the Adaptive
Coded Aperture algorithm implementation) to determine the
efficacy of this diffractive MEMS approach and to determine
the available system budget based on simulated bi-static
shutter-element DOF degradation (1 %, 5%, 10%, 20%, etc.)
trials until the degradation level where it is perceived to
necessitate component replacement. System performance
impacts, from DOF degradation, will manifest in a spatially
random method.},
Doi = {10.1117/12.745956},
Key = {fds280315}
}
@article{fds280316,
Author = {Badieirostami, M and Momtahan, O and Hsieh, CR and Adibi, A and Brady,
DJ},
Title = {An ultra-high resolution spectrometer with successive
combination of a Fabry-Perot etalon and a cylindrical beam
volume hologram},
Journal = {Conference on Lasers and Electro Optics, 2007, Cleo
2007},
Publisher = {IEEE},
Year = {2007},
Month = {December},
url = {http://dx.doi.org/10.1109/CLEO.2007.4453083},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a cylindrical beam volume
hologram. The combination of these two elements results in a
twodimensional spatial-spectral mapping in the output plane.
Using this spectrometer, ultra-high resolution (better than
0.2 nm) over a large bandwidth (larger than 300 nm) has been
experimentally demonstrated for diffuse light sources. ©
2007 Optical Society of America.},
Doi = {10.1109/CLEO.2007.4453083},
Key = {fds280316}
}
@article{fds280320,
Author = {Gehm, ME and John, R and Brady, DJ and Willett, RM and Schulz,
TJ},
Title = {Single-shot compressive spectral imaging with a
dual-disperser architecture.},
Journal = {Optics Express},
Volume = {15},
Number = {21},
Pages = {14013-14027},
Year = {2007},
Month = {October},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.15.014013},
Abstract = {This paper describes a single-shot spectral imaging approach
based on the concept of compressive sensing. The primary
features of the system design are two dispersive elements,
arranged in opposition and surrounding a binary-valued
aperture code. In contrast to thin-film approaches to
spectral filtering, this structure results in
easily-controllable, spatially-varying, spectral filter
functions with narrow features. Measurement of the input
scene through these filters is equivalent to projective
measurement in the spectral domain, and hence can be treated
with the compressive sensing frameworks recently developed
by a number of groups. We present a reconstruction framework
and demonstrate its application to experimental
data.},
Doi = {10.1364/oe.15.014013},
Key = {fds280320}
}
@article{fds280389,
Author = {Zheng, Y and Brady, DJ and Agarwal, PK},
Title = {Localization using boundary sensors: An analysis based on
graph theory},
Journal = {Acm Transactions on Sensor Networks},
Volume = {3},
Number = {4},
Pages = {21-es},
Publisher = {Association for Computing Machinery (ACM)},
Year = {2007},
Month = {October},
ISSN = {1550-4859},
url = {http://dx.doi.org/10.1145/1281492.1281496},
Abstract = {We consider sensors, such as fibers, lasers, and
pyroelectric motion detectors, that fire when objects cross
a boundary. A moving object can be localized by analyzing
sequences of boundary crossings. We consider the number of
distinct sequences and object positions that can be achieved
using boundary sensors in one- and two-dimensional spaces.
For 1D systems we use representations of sensor sequences on
graphs to derive limits on the number of object locations
that can be monitored by a given sensor population and
sequence length. For 2D systems we show that in certain
circumstances the ratio of the number of unique sensor
sequences to the number of unique object paths is
exponential in the sequence length and we argue that the
probability of unique identification is high for
sufficiently large sequences. We also prove the triangle
grid can track an object with error limited to a small
neighborhood. © 2007 ACM.},
Doi = {10.1145/1281492.1281496},
Key = {fds280389}
}
@article{fds280310,
Author = {Willett, RM and Gehm, ME and Brady, DJ},
Title = {Multiscale reconstruction for computational spectral
imaging},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6498},
Publisher = {SPIE},
Year = {2007},
Month = {August},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.715711},
Abstract = {In this work we develop a spectral imaging system and
associated reconstruction methods that have been designed to
exploit the theory of compressive sensing. Recent work in
this emerging field indicates that when the signal of
interest is very sparse (i.e. zero-valued at most locations)
or highly compressible in some basis, relatively few
incoherent observations are necessary to reconstruct the
most significant non-zero signal components. Conventionally,
spectral imaging systems measure complete data cubes and are
subject to performance limiting tradeoffs between spectral
and spatial resolution. We achieve single-shot full 3D data
cube estimates by using compressed sensing reconstruction
methods to process observations collected using an
innovative, real-time, dual-disperser spectral imager. The
physical system contains a transmissive coding element
located between a pair of matched dispersers, so that each
pixel measurement is the coded projection of the spectrum in
the corresponding spatial location in the spectral data
cube. Using a novel multiscale representation of the
spectral image data cube, we are able to accurately
reconstruct 256 × 256 × 15 spectral image cubes using just
256 × 256 measurements. © 2007 SPIE-IS&T.},
Doi = {10.1117/12.715711},
Key = {fds280310}
}
@article{fds280319,
Author = {Wagadarikar, AA and Gehm, ME and Brady, DJ},
Title = {Performance comparison of aperture codes for multimodal,
multiplex spectroscopy.},
Journal = {Applied Optics},
Volume = {46},
Number = {22},
Pages = {4932-4942},
Year = {2007},
Month = {August},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17676097},
Abstract = {We experimentally evaluate diverse static independent column
codes in a coded aperture spectrometer. The performance of
each code is evaluated based on the signal-to-noise ratio
(SNR), defined as the peak value in the spectrum to the
standard deviation of the background noise, as a function of
subpixel vertical misalignments. Among the code families
tested, an S-matrix-based code produces spectral
reconstructions with the highest SNR. The SNR is least
sensitive to vertical subpixel misalignments on the detector
with a Hadamard-matrix-based code. Finally, the increased
sensitivity of a spectrometer using a coded aperture instead
of a slit is demonstrated.},
Doi = {10.1364/ao.46.004932},
Key = {fds280319}
}
@article{fds280317,
Author = {Feller, SD and Chen, H and Brady, DJ and Gehm, ME and Hsieh, C and Momtahan, O and Adibi, A},
Title = {Multiple order coded aperture spectrometer.},
Journal = {Optics Express},
Volume = {15},
Number = {9},
Pages = {5625-5630},
Year = {2007},
Month = {April},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.15.005625},
Abstract = {We introduce a multiple order coded aperture (MOCA)
spectrometer. The MOCA is a system that uses a multiplex
hologram and a coded aperture to increase the spectral range
and throughput of the system over conventional spectrometers
while maintaining spectral resolution. This results in an
order of magnitude reduction in system volume with no loss
in resolution.},
Doi = {10.1364/oe.15.005625},
Key = {fds280317}
}
@article{fds280318,
Author = {Fernandez, C and Guenther, BD and Gehm, ME and Brady, DJ and Sullivan,
ME},
Title = {Longwave infrared (LWIR) coded aperture dispersive
spectrometer.},
Journal = {Optics Express},
Volume = {15},
Number = {9},
Pages = {5742-5753},
Year = {2007},
Month = {April},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.15.005742},
Abstract = {We describe a static aperture-coded, dispersive longwave
infrared (LWIR) spectrometer that uses a microbolometer
array at the detector plane. The two-dimensional aperture
code is based on a row-doubled Hadamard mask with
transmissive and opaque openings. The independent column
code nature of the matrix makes for a mathematically
well-defined pattern that spatially and spectrally maps the
source information to the detector plane. Post-processing
techniques on the data provide spectral estimates of the
source. Comparative experimental results between a slit and
coded aperture for emission spectroscopy from a CO(2) laser
are demonstrated.},
Doi = {10.1364/oe.15.005742},
Key = {fds280318}
}
@article{071310512221,
Author = {Fang, J-S and Hao, Q and Brady, DJ and Guenther, BD and Hsu,
KY},
Title = {A pyroelectric infrared biometric system for real-time
walker recognition by use of a maximum likelihood principal
components estimation (MLPCE) method.},
Journal = {Optics Express},
Volume = {15},
Number = {6},
Pages = {3271-3284},
Year = {2007},
Month = {March},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/OE.15.003271},
Keywords = {Biometrics;Maximum likelihood estimation;Object
recognition;Principal component analysis;Real time
control;},
Abstract = {This paper presents a novel biometric system for real-time
walker recognition using a pyroelectric infrared sensor, a
Fresnel lens array and signal processing based on the linear
regression of sensor signal spectra. In the model training
stage, the maximum likelihood principal components
estimation (MLPCE) method is utilized to obtain the
regression vector for each registered human subject.
Receiver operating characteristic (ROC) curves are also
investigated to select a suitable threshold for maximizing
subject recognition rate. The experimental results
demonstrate the effectiveness of the proposed pyroelectric
sensor system in recognizing registered subjects and
rejecting unknown subjects.},
Doi = {10.1364/oe.15.003271},
Key = {071310512221}
}
@article{fds280156,
Author = {Mahalanobis, A and Neifeld, M and Kumar, BVKV and Brady, D and Haberfelde, T and Muise, R},
Title = {Multiplexed point spread functions for image formation with
application to large area sensing and surveillance},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
ISSN = {2162-2701},
Key = {fds280156}
}
@article{fds280157,
Author = {Portnoy, A and Shankar, M and Pitsianis, N and Brady, D and Gibbons, R and Silver, A and Keller, D and Chen, C and Prather, D},
Title = {Depth of field with multi-aperture LWIR imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
Abstract = {We use a multiaperture approach to design a thin LWIR
camera. Having a shorter focal length, the microlens array
provides an extended depth of field over the conventional
system. © 2007 Optical Society of America.},
Key = {fds280157}
}
@article{fds280158,
Author = {Shankar, M and Pitsianis, N and Sun, X and Brady,
D},
Title = {Compressive measurements for video},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
Abstract = {Redundancies present in video streams could be used to
implement compressive sampling to achieve low power video
sensors. We explore the possibilities of using this in the
design of compressive video sensors and corresponding
algorithms. © 2007 Optical Society of America.},
Key = {fds280158}
}
@article{fds280162,
Author = {Kim, MS and Gehm, M and Brady, D},
Title = {Hyperspectral imager based on coded-aperture
spectroscopy},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
url = {http://dx.doi.org/10.1364/cosi.2007.cmc2},
Abstract = {A hyperspectral imager based on coded-aperture spectroscopy
has excellently generated 3-D data cube that provides 2-D
images of a sample with high selectivity of wavelength as
well as spectrum with meaningful spectral features. © 2007
Optical Society of America.},
Doi = {10.1364/cosi.2007.cmc2},
Key = {fds280162}
}
@article{fds280193,
Author = {Badieirostami, M and Momtahan, O and Hsieh, CR and Eftekhar, AA and Adibi, A and Brady, DJ},
Title = {An ultra-high resolution tandem fabry-perot etalon
cylindrical beam volume hologram spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a cylindrical beam volume
hologram. The combination of these two elements results in a
twodimensional spatial-spectral mapping in the output plane.
Using this spectrometer, ultra-high resolution (better than
0.2 nm) over a large bandwidth has been experimentally
demonstrated for diffuse light sources. © 2007 Optical
Society of America.},
Key = {fds280193}
}
@article{fds280194,
Author = {Badieirostami, M and Momtahan, O and Hsieh, CR and Adibi, A and Brady,
DJ},
Title = {An ultra-high resolution volume holographic
spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a cylindrical beam volume
hologram. The combination of these two elements results in a
twodimensional spatial-spectral mapping in the output plane.
Using this spectrometer, ultra-high resolution (better than
0.2 nm) over a large bandwidth has been experimentally
demonstrated for diffuse light sources. © 2007 Optical
Society of America.},
Key = {fds280194}
}
@article{fds280195,
Author = {Brady, DJ},
Title = {Multidimensional spatial and coherence imaging using single
shot spectral imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
Abstract = {A spectral imaging system may efficiently sense 10-100
spectral channels but the full data cube is often redundant.
We propose to exploit this redundancy to computationally
expand depth of field or obtain multidimensional spatial
images. © 2007 Optical Society of America.},
Key = {fds280195}
}
@article{fds280196,
Author = {Pitsianis, NP and Brady, DJ and Sun, X},
Title = {The MONTAGE least gradient image reconstruction},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
Abstract = {We introduce an image reconstruction algorithm for the
Compressive Optical MONTAGE Photography Initiative, for
recovering the resolution of an image from a set of aliased
subimages acquired by a lenslet array optical system. ©
2007 Optical Society of America.},
Key = {fds280196}
}
@article{fds280197,
Author = {McCain, ST and Willett, RM and Brady, DJ},
Title = {Coded-excitation Raman spectroscopy for Raman signal
estimation in highly fluorescent media},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
Abstract = {Raman signal estimation in highly fluorescent media is
investigated using multiple excitation lasers and an
iterative EM spectral reconstruction algorithm. Results from
an 8-laser system show estimation performance increases with
the number of excitation lasers. © 2007 Optical Society of
America.},
Key = {fds280197}
}
@article{fds280198,
Author = {Badieirostami, M and Momtahan, O and Hsieh, CR and Adibi, A and Brady,
DJ},
Title = {An ultra-high resolution spectrometer with successive
combination of a Fabry-Perot etalon and a cylindrical beam
volume hologram},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a cylindrical beam volume
hologram. The combination of these two elements results in a
twodimensional spatial-spectral mapping in the output plane.
Using this spectrometer, ultra-high resolution (better than
0.2 nm) over a large bandwidth (larger than 300 nm) has been
experimentally demonstrated for diffuse light sources. ©
2007 Optical Society of America.},
Key = {fds280198}
}
@article{fds280215,
Author = {Brady, DJ and John, R and Gehm, M and Schulz, T and Willett,
R},
Title = {Optical designs for compressive single shot spectral
imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
url = {http://dx.doi.org/10.1364/cosi.2007.cmc1},
Abstract = {Static mask coded aperture spectral imaging enables compact,
programmable coding for single shot measurements. We review
recent demonstrations of spectral imaging systems in the
DISP lab and describes trade-offs in dispersion and coding
system design. © 2007 Optical Society of
America.},
Doi = {10.1364/cosi.2007.cmc1},
Key = {fds280215}
}
@article{fds280216,
Author = {John, R and Brady, DJ and Willett, R and Gehm, M and Schulz,
T},
Title = {A snap-shot dual-disperser imager for compressive
hyperspectral imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2007},
Month = {January},
url = {http://dx.doi.org/10.1364/fio.2007.fthg3},
Abstract = {We demonstrate a single-shot, dual-disperser spectral
imaging system using coded apertures to perform compressive
imaging. We also describe associated multiscale
reconstruction algorithms to retrieve hyperspectral data
from single-shot image. We show simulated and experimental
results. © 2007 Optical Society of America.},
Doi = {10.1364/fio.2007.fthg3},
Key = {fds280216}
}
@article{071010465726,
Author = {Cull, EC and Gehm, ME and Brady, DJ and Hsieh, CR and Momtahan, O and Adibi, A},
Title = {Dispersion multiplexing with broadband filtering for
miniature spectrometers.},
Journal = {Applied Optics},
Volume = {46},
Number = {3},
Pages = {365-374},
Year = {2007},
Month = {January},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17228382},
Keywords = {Broadband networks;Diffraction gratings;Dispersion
(waves);Holography;Multiplexing;Optical filters;},
Abstract = {We replace the traditional grating used in a dispersive
spectrometer with a multiplex holographic grating to
increase the spectral range sensed by the instrument. The
multiplexed grating allows us to measure three different,
overlapping spectral bands on a color digital focal plane.
The detector's broadband color filters, along with a
computational inversion algorithm, let us disambiguate
measurements made from the three bands. The overlapping
spectral bands allow us to measure a greater spectral
bandwidth than a traditional spectrometer with the same
sized detector. Additionally, our spectrometer uses a static
coded aperture mask in the place of a slit. The aperture
mask allows increased light throughput, offsetting the
photon loss at the broadband filters. We present our
proof-of-concept dispersion multiplexing spectrometer design
with experimental measurements to verify its
operation.},
Doi = {10.1364/ao.46.000365},
Key = {071010465726}
}
@article{fds330746,
Author = {Linnehan, R and Brady, D and Schindler, J and Perlovsky, L and Rangaswamy, M},
Title = {On the design of SAR apertures using the Cramér-Rao
bound},
Journal = {Ieee Transactions on Aerospace and Electronic
Systems},
Volume = {43},
Number = {1},
Pages = {344-355},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2007},
Month = {January},
url = {http://dx.doi.org/10.1109/TAES.2007.357138},
Abstract = {The Cramér-Rao inequality is applied to the likelihood
function of the synthetic aperture radar (SAR) scatterer
parameter vector to relate the choice of flight path to
estimation performance. Estimation error bounds for the
scatterer parameter vector (including height) are developed
for multi-dimensional synthetic apertures, and quantify the
performance enhancement over a limited sector of the image
plane relative to standard-aperture single-pass SAR
missions. An efficient means for the design and analysis of
SAR waveforms and flight paths is proposed using simulated
scattering models that are limited in size. Comparison of
the error bounds to those for standard-aperture SAR show
that estimates of scatterer range and cross-range positions
are accurate for multi-dimensional aperture SAR, even with
the additional estimator for height. Furthermore,
multi-dimensional SAR is shown to address the layover
problem. © 2007 IEEE.},
Doi = {10.1109/TAES.2007.357138},
Key = {fds330746}
}
@article{fds280314,
Author = {Goodwin, S and Carlson, J and Rogers, S and Kim, J and Kim, C and Brady, D and Stoner, BR},
Title = {Dynamic aperture optical arrays based on polymeric MEMS
actuators for large scale coding elements with application
in visible to MWIR},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6714},
Publisher = {SPIE},
Year = {2007},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.736074},
Abstract = {Extension of coded apertures to the MWIR introduces the
effects of diffraction and other distortions not observed in
shorter wavelength systems. A new approach is being
developed under the DARPA/SPO funded LACOSTE (Large Area
Coverage Optical search-while Track and Engage) program,
that addresses the effects of diffraction while gaining the
benefits of coded apertures, thus providing flexibility to
vary resolution, possess sufficient light gathering power,
and achieve a wide field of view (WFOV). The photonic MEMS
"eyelid" array technology is currently being instantiated in
this DARPA Surveillance program study as the "heart",
mediating the flow of the incoming signal. However, speed,
lifetime, packaging and scalability are critical factors for
the MEMS "eyelid" technology which will determine system
efficacy as well as military and commercial usefulness. The
electronic eyelid array is the fundamental addressable unit
for adaptive code generation and will allow the system to
multiplex in time for increased resolution. The binary code
which determines whether a 500μm eyelid is open or closed
is referred to as the "eyelid code." Groups of eyelids can
work together as a "super aperture" by virtue of a
"macro-code." A macro code becomes relevant to describe how
dispersed eyelids across the 0.19m × 0.19m aperture will
function together. Dynamic aperture arrays were fabricated
on both quartz and sapphire substrates for operation in the
visible to MWIR. Both 8×8 and 40×40 element arrays were
designed, fabricated, and tested with macro-codes consisting
of 4, 8, and 16 unique combinations. The die were packaged
and tested in ambient for robust eyelid operations. The
point spread function was also measured in an optical setup
with the eyelid arrays located in the aperture
plane.},
Doi = {10.1117/12.736074},
Key = {fds280314}
}
@article{fds280268,
Author = {Schultz, J and Mrksich, M and Bhatia, SN and Brady, DJ and Ricco, AJ and Walt, DR and Wilkins, CL},
Title = {Biosensing: International research and development},
Journal = {Biosensing},
Pages = {1-387},
Publisher = {Springer Netherlands},
Year = {2006},
Month = {December},
url = {http://dx.doi.org/10.1007/1-4020-4058-X},
Abstract = {The goal of this book is to disseminate information on the
worldwide status and trends in biosensing R&D to government
decisionmakers and the research community. The contributors
critically analyze and compare biosensing research in the
United States with that being pursued in Japan, Europe and
other major industrialized countries. Biosensing includes
systems that incorporate a variety of means, including
electrical, electronic, and photonic devices; biological
materials (e.g., tissue, enzymes, nucleic acids, etc.); and
chemical analysis to produce detectable signals for the
monitoring or identification of biological phenomena. In a
broader sense, the study of biosensing includes any approach
to detection of biological elements and the associated
software or computer identification technologies (e.g.,
imaging) that identify biological characteristics.
Biosensing is finding a growing number of applications in a
wide variety of areas, including biomedicine, food
production and processing, and detection of bacteria,
viruses, and biological toxins for biowarfare defense.
Subtopics likely to be covered in this study include the
following: Nucleic acid sensors and DNA chips and arrays,
organism-and cell-based biosensors, bioelectronics and
biometrics, biointerfaces and biomaterials; biocompatibility
and biofouling, integrated, multi-modality sensors and
sensor networks, system issues, including signal
transduction, data interpretation, and validation, novel
sensing algorithms, e.g., non-enzyme-based sensors for
glucose, mechanical sensors for prosthetics, related issues
in bio-MEMS and NEMS (microelectromechanical and
nanoelectromechanical systems), possibly including
actuators, applications in biomedicine, the environment,
food industry, security and defense. Particular emphasis
will be on technologies that may lead to portable or
fieldable devices/instruments. Important consideration will
be given to an integrated approach to detection, storage,
analysis, validation, interpretation and presentation of
results from the biosensing system. Focus will be on
research from the following disciplines: BioMems & nano,
optical spectroscopy, mass spectroscopy, chemometrics,
pattern recognition, telemetry, signal processing, and
toxicology. Finally, beyond the above technical issues, the
study will also address the following non-technical issues:
Mechanisms for enhancing international and interdisciplinary
cooperation in the field, opportunities for shortening the
lead time for deployment of new biosensing technologies
emerging from the laboratory, long range research,
educational, and infrastructure issues that need addressed
to promote better progress in the field, current government
R&D funding levels overseas compared to the United States,
to the extent data are available. © 2006 Springer. All
Rights Reserved.},
Doi = {10.1007/1-4020-4058-X},
Key = {fds280268}
}
@article{fds280269,
Author = {Brady, DJ},
Title = {Information systems for biosensing},
Pages = {107-119},
Publisher = {Springer Netherlands},
Year = {2006},
Month = {December},
url = {http://dx.doi.org/10.1007/1-4020-4058-X_7},
Doi = {10.1007/1-4020-4058-X_7},
Key = {fds280269}
}
@article{fds280309,
Author = {Linnehan, R and Schindler, J and Brady, D},
Title = {Evaluation and tuning of a SAR detector using sparse-array
spotlight mode simulations},
Journal = {2006 Ieee Sensor Array and Multichannel Signal Processing
Workshop Proceedings, Sam 2006},
Pages = {315-319},
Publisher = {IEEE},
Year = {2006},
Month = {December},
url = {http://dx.doi.org/10.1109/SAM.2006.1677211},
Abstract = {We describe a method of tuning a simple detection process of
stationary targets in SAR images. The tuning metric accounts
for the squared-error performance of prescient estimators of
target location and reflectivity. The efficiencies of these
prescient estimators are compared to their Cramér Rao
bounds (CRBs). The off-line tuning is performed by
collecting statistics of scatterer estimation in SAR images
created using sparse-array spotlight mode simulations. ©
2006 IEEE.},
Doi = {10.1109/SAM.2006.1677211},
Key = {fds280309}
}
@article{070210353287,
Author = {Guo, J and Adato, R and Brady, DJ},
Title = {Single-shot subpixel response measurement with an aperture
array pixel mask.},
Journal = {Optics Letters},
Volume = {31},
Number = {23},
Pages = {3441-3443},
Year = {2006},
Month = {December},
ISSN = {0146-9592},
url = {http://dx.doi.org/10.1364/OL.31.003441},
Keywords = {Image processing;CMOS integrated circuits;Image
sensors;Optical resolving power;},
Abstract = {We first point out that the subpixel response function is
another kernel function in digital imaging. Then we show
that the subpixel response function of CMOS imaging sensor
pixels can be measured with an aperture array pixel mask in
a single-shot image capture. Our technique permits
high-resolution subpixel response function measurement of
imaging pixels for superresolution imaging
applications.},
Doi = {10.1364/ol.31.003441},
Key = {070210353287}
}
@article{065210331906,
Author = {Hao, Q and Brady, DJ and Guenther, BD and Burchett, JB and Shankar, M and Feller, S},
Title = {Human tracking with wireless distributed pyroelectric
sensors},
Journal = {Ieee Sensors Journal},
Volume = {6},
Number = {6},
Pages = {1683-1695},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
Month = {December},
ISSN = {1530-437X},
url = {http://dx.doi.org/10.1109/JSEN.2006.884562},
Keywords = {Pyroelectricity;Signal processing;Algorithms;Software
prototyping;Arrays;Computation theory;Numerical
methods;},
Abstract = {This paper presents a wireless pyroelectric sensor system,
composed of sensing modules (slaves), a synchronization and
error rejection module (master), and a data fusion module
(host), to perform human tracking. The computation workload
distribution among slave, master, and host is investigated.
The performances and costs of different signal-processing
and target-tracking algorithms are discussed. A prototype
system is described containing pyroelectric sensor modules
that are able to detect the angular displacement of a moving
thermal target. Fresnel lens arrays are used to modulate the
sensor field of view. The sensor system has been used to
track a single human target. © 2006 IEEE.},
Doi = {10.1109/JSEN.2006.884562},
Key = {065210331906}
}
@article{064710259832,
Author = {Dillon, T and Marchena, E and Chen, C and Brady, D and Prather,
D},
Title = {Microlens fabrication using HEBS glass for compact
high-resolution IR imaging system},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6327},
Pages = {632770 -},
Publisher = {SPIE},
Address = {San Diego, CA, United States},
Year = {2006},
Month = {November},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.681222},
Keywords = {Fabrication;Glass;Infrared imaging;Optical resolving
power;Optimization;Image reconstruction;Imaging
systems;},
Abstract = {Under the DARPA COMP-I (Compressive Optical MONTAGE
Photography Initiative) program, the goal of this project is
to significantly reduce the volume and form factor of
infrared imaging systems without loss of resolution. The
approach taken is to use an array of small lenses with
extremely short focal lengths rather than the conventional
approach of a single aperture lens system with large
diameter and focal length. The array of lenses creates
multiple copies of the scene on a single focal plane
detector array, which are then used to reconstruct an image
with resolution comparable to or higher than that of the
conventional imaging system. This is achieved by a
computational method known as super-resolution
reconstruction. Work at the University of Delaware towards
this end includes participation in the design and
optimization of the optical system along with fabrication of
some of the optical elements. Grayscale lithography using a
high-energy beam sensitive (HEBS) glass photomask and
proportional dry etch pattern transfer are the key
techniques enabling the fabrication process. In this paper
we will discuss the design of the imaging system while
focusing on the fabrication aspects of the
project.},
Doi = {10.1117/12.681222},
Key = {064710259832}
}
@article{064610232537,
Author = {Brady, DJ},
Title = {Leith-Upatnieks holography in computational
sensors},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6311},
Pages = {63111 -},
Publisher = {SPIE},
Address = {San Diego, CA, United States},
Year = {2006},
Month = {November},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.686729},
Keywords = {Optical sensors;Signal filtering and prediction;Spectrometers;Holography;},
Abstract = {Holographic optical elements are a critically enabling
component of modern spectroscopy and spectral imaging
systems. While the most common holographic elements are
essentially those discovered in 1962 by Leith and Upatnieks,
several decades passed prior to the effective integration of
holography and sensing. Over 5 decades Emmett Leith was a
prime mover in both the birth and the maturation of
computational holographic sensors. Recent demonstrations of
the unique utility of holographic filtering suggest that
continued improvements in materials and recording processes
for Leith's original concept will yield tremendous results.
This paper describes the multiple order coded aperture
(MOCA) spectrometer as an example of the potential for
advanced holography in computational sensors.},
Doi = {10.1117/12.686729},
Key = {064610232537}
}
@article{064510219629,
Author = {Shankar, M and Willett, R and Pitsianis, NP and Te Kolste and R and Chen,
C and Gibbons, R and Brady, DJ},
Title = {Ultra-thin Multiple-channel LWIR Imaging
Systems},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6294},
Pages = {629411 -},
Publisher = {SPIE},
Address = {San Diego, CA, United States},
Year = {2006},
Month = {November},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.681386},
Keywords = {Cameras;Optical resolving power;Image reconstruction;Lenses;Diffraction;Image
quality;Wavelet transforms;},
Abstract = {Infrared camera systems may be made dramatically smaller by
simultaneously collecting several low-resolution images with
multiple narrow aperture lenses rather than collecting a
single high-resolution image with one wide aperture lens.
Conventional imaging systems consist of one or more optical
elements that image a scene on the focal plane. The
resolution depends on the wavelength of operation and the
f-number of the lens system, assuming a diffraction limited
operation. An image of comparable resolution may be obtained
by using a multi-channel camera that collects multiple
low-resolution measurements of the scene and then
reconstructing a high-resolution image. The proposed
infrared sensing system uses a three-by-three lenslet array
with an effective focal length of 1.9mm and overall system
length of 2.3mm, and we achieve image resolution comparable
to a conventional single lens system having a focal length
of 5.7mm and overall system length of 26mm. The
high-resolution final image generated by this system is
reconstructed from the noisy low-resolution images
corresponding to each lenslet; this is accomplished using a
computational process known as superresolution
reconstruction. The novelty of our approach to the
superresolution problem is the use of wavelets and related
multiresolution method within a Expectation-Maximization
framework to improve the accuracy and visual quality of the
reconstructed image. The wavelet-based regularization
reduces the appearance of artifacts while preserving key
features such as edges and singularities. The processing
method is very fast, making the integrated sensing and
processing viable for both time-sensitive applications and
massive collections of sensor outputs.},
Doi = {10.1117/12.681386},
Key = {064510219629}
}
@article{070910440931,
Author = {Agarwal, PK and Brady, D and Matoušek, J},
Title = {Segmenting object space by geometric reference
structures},
Journal = {Acm Transactions on Sensor Networks},
Volume = {2},
Number = {4},
Pages = {455-465},
Publisher = {Association for Computing Machinery (ACM)},
Year = {2006},
Month = {November},
ISSN = {1550-4859},
url = {http://dx.doi.org/10.1145/1218556.1218557},
Keywords = {Computational geometry;Mathematical models;Pattern
recognition;Sensors;Telecommunication networks;},
Abstract = {A model for segmentation of an object space by an array of
binary, radiation-field sensors and geometric reference
structures is described. Given a family of binary,
radiation-field sensors and a geometric reference structure,
we refer to the set of sensor states induced by a source at
point p as the signature of p. We study the segmentation of
an object space into signature cells and prove near optimal
bounds on the number of distinct signatures induced by a
point source, as a function of sensor and reference
structure complexity. We also show that almost any family of
signatures can be implemented under this model. © 2006
ACM.},
Doi = {10.1145/1218556.1218557},
Key = {070910440931}
}
@article{070310366393,
Author = {Shankar, M and Burchett, JB and Hao, Q and Guenther, BD and Brady,
DJ},
Title = {Human-tracking systems using pyroelectric infrared
detectors},
Journal = {Optical Engineering},
Volume = {45},
Number = {10},
Pages = {106401-106401},
Publisher = {SPIE-Intl Soc Optical Eng},
Year = {2006},
Month = {October},
ISSN = {0091-3286},
url = {http://dx.doi.org/10.1117/1.2360948},
Keywords = {Infrared detectors;Pyroelectricity;Tracking (position);Light
modulation;Visibility;Optical design;},
Abstract = {We design and develop a low-cost pyroelectric detector-based
IR motion-tracking system. We study the characteristics of
the detector and the Fresnel lenses that are used to
modulate the visibility of the detectors. We build sensor
clusters in different configurations and demonstrate their
use for human motion tracking. © 2006 Society of
Photo-Optical Instrumentation Engineers.},
Doi = {10.1117/1.2360948},
Key = {070310366393}
}
@article{063810119325,
Author = {Pitsianis, NP and Brady, DJ and Portnoy, A and Sun, X and Suleski, T and Fiddy, MA and Feldman, MR and Tekolste, RD},
Title = {Compressive imaging sensors},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6232},
Pages = {62320 -},
Publisher = {SPIE},
Address = {Kissimmee, FL, United States},
Year = {2006},
Month = {September},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.666451},
Keywords = {Photography;Multiplexing;Sampling;Benchmarking;Image
coding;Decoding;},
Abstract = {This paper describes a compressive sensing strategy
developed under the Compressive Optical MONTAGE Photography
Initiative. Multiplex and multi-channel measurements are
generally necessary for compressive sensing. In a
compressive imaging system described here, static focal
plane coding is used with multiple image apertures for
non-degenerate multiplexing and multiple channel sampling.
According to classical analysis, one might expect the number
of pixels in a reconstructed image to equal the total number
of pixels across the sampling channels, but we demonstrate
that the system can achieve up to 50% compression with
conventional benchmarking images. In general, the
compression rate depends on the compression potential of an
image with respect to the coding and decoding schemes
employed in the system.},
Doi = {10.1117/12.666451},
Key = {063810119325}
}
@article{071210493897,
Author = {Hamza, AB and Brady, DJ},
Title = {Reconstruction of reflectance spectra using robust
nonnegative matrix factorization},
Journal = {Ieee Transactions on Signal Processing},
Volume = {54},
Number = {9},
Pages = {3637-3642},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
Month = {September},
ISSN = {1053-587X},
url = {http://dx.doi.org/10.1109/TSP.2006.879282},
Keywords = {Algorithms;Cost functions;Optimization;Principal component
analysis;Spectroscopic analysis;Statistics;},
Abstract = {In this correspondence, we present a robust statistics-based
nonnegative matrix factorization (RNMF) approach to recover
the measurements in reflectance spectroscopy. The proposed
algorithm is based on the minimization of a robust cost
function and yields two equations updated alternatively.
Unlike other linear representations, such as principal
component analysis, the RNMF technique is resistant to
outliers and generates nonnegative-basis functions, which
balance the logical attractiveness of measurement functions
against their physical feasibility. Experimental results on
a spectral library of reflectance spectra are presented to
illustrate the much improved performance of the RNMF
approach. © 2006 IEEE.},
Doi = {10.1109/TSP.2006.879282},
Key = {071210493897}
}
@article{063410079174,
Author = {Brady, DJ and Gehm, ME},
Title = {Compressive imaging spectrometers using coded
apertures},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6246},
Pages = {62460 -},
Publisher = {SPIE},
Address = {Kissimmee, FL, United States},
Year = {2006},
Month = {August},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.667605},
Keywords = {Imaging systems;Spectrum analysis;Computation theory;Image
sensors;Spectroscopic analysis;},
Abstract = {A spectral imager provides a 3-D data cube in which the
spatial information (2-D) of the image is comple-mented by
spectral information (1-D) about each spatial location.
Typically, these systems are operated in a fully-determined
(or overdetermined) manner so that the measurements can be
computationally inverted into a reliable estimate of the
source. We propose a notional system design that is highly
underdetermined, yet still computationally invertable. This
approach relies on recently-developed concepts in
compressive sensing. Because the number of required
measurements is greatly reduced from traditional designs,
the result is a faster and more economical sensor
system.},
Doi = {10.1117/12.667605},
Key = {063410079174}
}
@article{9324013,
Author = {Fang, J-S and Hao, Q and Brady, DJ and Guenther, BD and Hsu,
KY},
Title = {Real-time human identification using a pyroelectric infrared
detector array and hidden Markov models.},
Journal = {Optics Express},
Volume = {14},
Number = {15},
Pages = {6643-6658},
Year = {2006},
Month = {July},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.14.006643},
Keywords = {biometrics (access control);expectation-maximisation
algorithm;feature extraction;hidden Markov models;image
motion analysis;infrared detectors;lenses;optical
arrays;pyroelectric detectors;},
Abstract = {This paper proposes a real-time human identification system
using a pyroelectric infrared (PIR) detector array and
hidden Markov models (HMMs). A PIR detector array with
masked Fresnel lens arrays is used to generate digital
sequential data that can represent a human motion feature.
HMMs are trained to statistically model the motion features
of individuals through an expectation-maximization (EM)
learning process. Human subjects are recognized by
evaluating a set of new feature data against the trained
HMMs using the maximum-likelihood (ML) criterion. We have
developed a prototype system to verify the proposed method.
Sensor modules with different numbers of detectors and
different sampling masks were tested to maximize the
identification capability of the sensor system.},
Doi = {10.1364/oe.14.006643},
Key = {9324013}
}
@article{06269967812,
Author = {McCain, ST and Gehm, ME and Wang, Y and Pitsianis, NP and Brady,
DJ},
Title = {Multimodal multiplex Raman spectroscopy optimized for in
vivo chemometrics},
Journal = {Progress in Biomedical Optics and Imaging Proceedings of
Spie},
Volume = {6093},
Pages = {60930 -},
Publisher = {SPIE},
Address = {San Jose, CA, United States},
Year = {2006},
Month = {June},
ISSN = {1605-7422},
url = {http://dx.doi.org/10.1117/12.646755},
Keywords = {Raman spectroscopy;Signal processing;Electric
excitation;Regression analysis;},
Abstract = {We have designed and constructed a multimodal multiplex
Raman spectrometer which uses multi-wavelength excitation to
better detect signals in the presence of fluorescence by
taking advantage of the shift-variance of the Raman signal
with respect to excitation frequency. Coupled with
partial-least-squares (PLS) regression, the technique
applied to ethanol estimation in a tissue phantom achieves
root-mean-squared-cross-validation errors (RMSCVE) of 9.2
mmol/L with a model formed with 2 principal components,
compared to a single wavelength data set with equivalent
energy where 7 principal components were used to achieve an
RMSCVE of 39.1 mmol/L.},
Doi = {10.1117/12.646755},
Key = {06269967812}
}
@article{06199863575,
Author = {Gehm, ME and Brady, DJ},
Title = {High-throughput hyperspectral microscopy},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6090},
Pages = {609007 -},
Publisher = {SPIE},
Address = {San Jose, CA, United States},
Year = {2006},
Month = {May},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.644828},
Keywords = {Microscopic examination;Product design;Computerized
tomography;Fourier transform infrared spectroscopy;},
Abstract = {A hyperspectral imager provides a 3-D data cube in which the
spatial information (2-D) of the image is complemented by
spectral information (1-D) about each spatial location. A
static, high-throughput spectrometer design previously
developed by our group can be used as the spectral engine in
a high-throughput hyperspectral imager that avoids the
Fourier undersampling issues present in previous dispersive
designs. We present the theory for both pushbroom and
tomographic operation and describe experimental results from
our proof-of-concept implementation of a hyperspectral
microscope.},
Doi = {10.1117/12.644828},
Key = {06199863575}
}
@article{06259945935,
Author = {Neifeld, MA and Mahalanobis, A and Brady, DJ},
Title = {Task-specific sensing--introduction.},
Journal = {Applied Optics},
Volume = {45},
Number = {13},
Pages = {2857-2858},
Year = {2006},
Month = {May},
ISSN = {1559-128X},
url = {http://dx.doi.org/10.1364/AO.45.002857},
Keywords = {Computer hardware;Optical sensors;Signal
processing;Optimization;Algorithms;Data acquisition;Spectroscopic
analysis;},
Abstract = {Task-specific sensing (TSS), a concept concerned with the
joint optimization of optical and/or hardware and
computational degrees of freedom toward the optimal solution
of a task, is discussed. TSS mitigates the limitations of
traditional optical sensing and sensor information
processing. Traditional approaches to sensing and sensor
signal processing employ separate design and/or optimization
strategies. This approach ignores the opportunity for tasks
and algorithms to influence the type, the complexity, or the
quantity of data gathered by sensors. TSS is a powerful
framework for the design and analysis of optical systems for
spectroscopy and 3D imaging.},
Doi = {10.1364/ao.45.002857},
Key = {06259945935}
}
@article{06259945945,
Author = {Momtahan, O and Hsieh, CR and Adibi, A and Brady,
DJ},
Title = {Analysis of slitless holographic spectrometers implemented
by spherical beam volume holograms.},
Journal = {Applied Optics},
Volume = {45},
Number = {13},
Pages = {2955-2964},
Year = {2006},
Month = {May},
ISSN = {1559-128X},
url = {http://dx.doi.org/10.1364/AO.45.002955},
Keywords = {Spectrometers;Slitting;Fourier transforms;Lenses;Charge
coupled devices;Optical collimators;Feature
extraction;},
Abstract = {The analysis of a slitless volume holographic spectrometer
is presented in detail. The spectrometer is based on a
spherical beam volume hologram followed by a
Fourier-transforming lens and a CCD. It is shown that the
spectrometer is not sensitive to the incident angle of the
input beam for the practical range of applications. A
holographic spectrometer based on the conventional
implementation is also analyzed, and the results are used to
compare the performance of the proposed method with the
conventional one. The experimental results are consistent
with the theoretical study. It is also shown that the
slitless volume holographic spectrometer lumps three
elements (the entrance slit, the collimator, and the
diffractive element) of the conventional spectrometer into
one spherical beam volume hologram. Based on the unique
features of the slitless volume holographic spectrometer, we
believe it is a good candidate for portable spectroscopy for
environmental and biological applications.},
Doi = {10.1364/ao.45.002955},
Key = {06259945945}
}
@article{06259945952,
Author = {Burchett, J and Shankar, M and Hamza, AB and Guenther, BD and Pitsianis,
N and Brady, DJ},
Title = {Lightweight biometric detection system for human
classification using pyroelectric infrared
detectors.},
Journal = {Applied Optics},
Volume = {45},
Number = {13},
Pages = {3031-3037},
Year = {2006},
Month = {May},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16639451},
Keywords = {Image sensors;Human engineering;Pyroelectricity;Plastic
lenses;Arrays;Algorithms;Principal component
analysis;Regression analysis;},
Abstract = {We use pyroelectric detectors that are differential in
nature to detect motion in humans by their heat emissions.
Coded Fresnel lens arrays create boundaries that help to
localize humans in space as well as to classify the nature
of their motion. We design and implement a low-cost
biometric tracking system by using off-the-shelf components.
We demonstrate two classification methods by using data
gathered from sensor clusters of dual-element pyroelectric
detectors with coded Fresnel lens arrays. We propose two
algorithms for person identification, a more generalized
spectral clustering method and a more rigorous example that
uses principal component regression to perform a blind
classification.},
Doi = {10.1364/ao.45.003031},
Key = {06259945952}
}
@article{06259945944,
Author = {Lepage, K and Thomson, DJ and Kraut, S and Brady,
DJ},
Title = {Multitaper scan-free spectrum estimation using a rotational
shear interferometer.},
Journal = {Applied Optics},
Volume = {45},
Number = {13},
Pages = {2940-2954},
Year = {2006},
Month = {May},
ISSN = {1559-128X},
url = {http://dx.doi.org/10.1364/AO.45.002940},
Keywords = {Spectrum analysis;Algorithms;Gaussian noise
(electronic);Signal to noise ratio;Feature
extraction;Computer simulation;},
Abstract = {Multitaper methods for a scan-free spectrum estimation that
uses a rotational shear interferometer are investigated.
Before source spectra can be estimated the sources must be
detected. A source detection algorithm based upon the
multitaper F-test is proposed. The algorithm is simulated,
with additive, white Gaussian detector noise. A source with
a signal-to-noise ratio (SNR) of 0.71 is detected 2.9
degrees from a source with a SNR of 70.1, with a
significance level of 10(-4), approximately 4 orders of
magnitude more significant than the source detection
obtained with a standard detection algorithm. Interpolation
and the use of prewhitening filters are investigated in the
context of rotational shear interferometer (RSI) source
spectra estimation. Finally, a multitaper spectrum estimator
is proposed, simulated, and compared with untapered
estimates. The multitaper estimate is found via simulation
to distinguish a spectral feature with a SNR of 1.6 near a
large spectral feature. The SNR of 1.6 spectral feature is
not distinguished by the untapered spectrum estimate. The
findings are consistent with the strong capability of the
multitaper estimate to reduce out-of-band spectral
leakage.},
Doi = {10.1364/ao.45.002940},
Key = {06259945944}
}
@article{06169823020,
Author = {Portnoy, AD and Pitsianis, NP and Brady, DJ and Guo, J and Fiddy, MA and Feldman, MR and Te Kolste and RD},
Title = {Thin digital imaging systems using focal plane
coding},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6065},
Pages = {60650 -},
Publisher = {SPIE},
Address = {San Jose, CA, United States},
Year = {2006},
Month = {April},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.643203},
Keywords = {Image coding;Information analysis;Frequency
response;},
Abstract = {With this work we show the use of focal plane coding to
produce nondegenerate data between subapertures of an
imaging system. Subaperture data is integrated to form a
single high resolution image. Multiple apertures generate
multiple copies of a scene on the detector plane. Placed in
the image plane, the focal plane mask applies a unique code
to each of these sub-images. Within each sub-image, each
pixel is masked so that light from only certain optical
pixels reaches the detector. Thus, each sub-image measures a
different linear combination of optical pixels. Image
reconstruction is achieved by inversion of the
transformation performed by the imaging system. Registered
detector pixels in each sub-image represent the magnitude of
the projection of the same optical information onto
different sampling vectors. Without a coding element, the
imaging system would be limited by the spatial frequency
response of the electronic detector pixel. The small mask
features allow the imager to broaden this response and
reconstruct higher spatial frequencies than a conventional
coarsely sampling focal plane. © 2006 SPIE-IS&T.},
Doi = {10.1117/12.643203},
Key = {06169823020}
}
@article{06139789578,
Author = {Zheng, Y and Pitsianis, NP and Brady, DJ},
Title = {Nonadaptive group testing based fiber sensor deployment for
multiperson tracking},
Journal = {Ieee Sensors Journal},
Volume = {6},
Number = {2},
Pages = {490-494},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
Month = {April},
ISSN = {1530-437X},
url = {http://dx.doi.org/10.1109/JSEN.2006.870159},
Keywords = {Tracking (position);Optical fibers;Light
transmission;},
Abstract = {We demonstrate a novel use of nonadaptive group testing in
the design and implementation of a fiber sensor floor web
for the localization and tracking of multiple individuals.
We validate our design with a floor web woven with optical
fiber threads that form a grid of cells, with a different
subset of fibers on each cell. Sensors detect the presence
of a person by the change in light transmission due to
microbending when a fiber is stepped upon. Nonadaptive group
testing permits the determination of a minimum number of
sensors and the proper allocation of monitored cells to each
sensor. The simultaneous presence of individuals on any
combination of up to a small number of cells generates a
unique sensor response. Our proof of concept implementation
of an 8 × 8 grid requires the use of only 16 sensors and
off-the-shelf inexpensive components to decipher the
position of up to two individuals. This experiment proves
the feasibility of our design and its extensibility to
higher number of cells and simultaneous targets. © 2006
IEEE.},
Doi = {10.1109/JSEN.2006.870159},
Key = {06139789578}
}
@article{fds280155,
Author = {Shankar, M and Willett, R and Pitsianis, N and Brady, D and Schulz, T and Gibbons, B and Te Kolste and B and Carriere, J and Chen,
C},
Title = {Ultra-thin multi-aperture LWIR imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We design and implement an ultra-thin LWIR camera by
replacing the conventional lens system with a micro-lens
array. The resulting low resolution images can be used to
reconstruct a high resolution image by post processing. ©
2006 Optical Society of America.},
Key = {fds280155}
}
@article{fds280183,
Author = {Brady, DJ},
Title = {Compressive sampling in spectral imaging
systems},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {Optical prefilters shape the analog-digital interface in
imaging systems to implement generalized spatio-spectral
sampling. The Duke Imaging and Spectroscopy Program explores
generalized sampling systems, this talk focuses specifically
on spectral encoding for compressive spatial imaging. ©
2005 Optical Society of America.},
Key = {fds280183}
}
@article{fds280184,
Author = {Guo, J and Wang, G and Brady, DJ},
Title = {Super-resolution mapping of flow velocity distribution in
nanofluidic channels},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We will show a super-resolution mapping technique for
measuring the flow velocity distribution in nanofluidic
channels. The mapping resolution can be much smaller than
the diffraction limit of the optical imaging system. © 2006
Optical Society of America.},
Key = {fds280184}
}
@article{fds280185,
Author = {Guo, J and Wang, G and Brady, DJ},
Title = {Super-resolution mapping of flow velocity distribution in
nanofluidic channels},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We will show a super-resolution mapping technique for
measuring the flow velocity distribution in nanofluidic
channels. The mapping resolution can be much smaller than
the diffraction limit of the optical imaging system. © 2006
Optical Society of America.},
Key = {fds280185}
}
@article{fds280186,
Author = {McCain, ST and Willett, R and Brady, DJ},
Title = {Coded-excitation Raman spectroscopy for ethanol chemometrics
of tissue},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {Raman spectroscopy of bulk tissue is challenging due to
sample auto-fluorescence and weak Raman cross-sections of
most molecules. We investigate the use of coded-excitation
Raman spectroscopy coupled with an iterative algorithm for
Raman signal estimation. © 2006 Optical Society of
America.},
Key = {fds280186}
}
@article{fds280187,
Author = {Badieirostami, M and Momtahan, O and Adibi, A and Brady,
DJ},
Title = {A compact Fabry-Perot grating cascaded spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a grating. The grating expands
the limited spectral range of the Fabry-Perot and the
combination of both elements results in a powerful
spectrometer with good two-dimensional spatial-spectral
diversity in the output plane. © 2006 Optical Society of
America.},
Key = {fds280187}
}
@article{fds280188,
Author = {Badieirostami, M and Momtahan, O and Adibi, A and Brady,
DJ},
Title = {A compact fabry-perot grating cascaded spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a grating. The grating expands
the limited spectral range of the Fabry-Perot and the
combination of both elements results in a powerful
spectrometer with good two-dimensional spatial-spectral
diversity in the output plane. © 2006 Optical Society of
America.},
Key = {fds280188}
}
@article{fds280189,
Author = {Badieirostami, M and Momtahan, O and Adibi, A and Brady,
DJ},
Title = {A compact fabry-perot grating cascaded spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a grating. The grating expands
the limited spectral range of the Fabry-Perot and the
combination of both elements results in a powerful
spectrometer with good two-dimensional spatial-spectral
diversity in the output plane. © 2006 Optical Society of
America.},
Key = {fds280189}
}
@article{fds280190,
Author = {Badieirostami, M and Momtahan, O and Adibi, A and Brady,
DJ},
Title = {A compact fabry-perot grating cascaded spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a grating. The grating expands
the limited spectral range of the Fabry-Perot and the
combination of both elements results in a powerful
spectrometer with good two-dimensional spatial-spectral
diversity in the output plane. © 2006 Optical Society of
America.},
Key = {fds280190}
}
@article{fds280191,
Author = {Guo, J and Wang, G and Brady, DJ},
Title = {Super-resolution mapping of flow velocity distribution in
nanofluidic channels},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We will show a super-resolution mapping technique for
measuring the flow velocity distribution in nanofluidic
channels. The mapping resolution can be much smaller than
the diffraction limit of the optical imaging system. © 2006
Optical Society of America.},
Key = {fds280191}
}
@article{fds280192,
Author = {Guo, J and Wang, G and Brady, DJ},
Title = {Super-resolution mapping of flow velocity distribution in
nanofluidic channels},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We will show a super-resolution mapping technique for
measuring the flow velocity distribution in nanofluidic
channels. The mapping resolution can be much smaller than
the diffraction limit of the optical imaging system. © 2006
Optical Society of America.},
Key = {fds280192}
}
@article{fds280207,
Author = {Gehm, ME and Portnoy, AD and Brady, DJ},
Title = {Dual-disperser design for single-shot computational spectral
imaging},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
url = {http://dx.doi.org/10.1364/fio.2006.fmb3},
Abstract = {We describe a dual-disperser approach to computational
spectral imaging. This approach enables flexible code design
and avoids problems present in single-disperser systems. We
will report on a prototype single-shot spectral imager based
on these ideas. © 2006 Optical Society of
America.},
Doi = {10.1364/fio.2006.fmb3},
Key = {fds280207}
}
@article{fds280208,
Author = {Fernandez, C and Guenther, BD and Gehm, ME and Brady, DJ and Sullivan,
ME},
Title = {Longwave infrared (LWIR) coded aperture dispersive
spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We describe a static aperture-coded, dispersive longwave
infrared (LWIR) spectrometer that uses a microbolometer
array as the detector plane. We present experimental results
of absorption spectroscopy for a variety of sources. © 2006
Optical Society of America.},
Key = {fds280208}
}
@article{fds280209,
Author = {Wagadarikar, AA and Gehm, ME and Brady, DJ},
Title = {Evaluation of aperture codes for high throughput
spectroscopy},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
url = {http://dx.doi.org/10.1364/fio.2006.fmb5},
Abstract = {A coded aperture spectrometer maintains the spectral
resolution of a traditional slit spectrometer while
dramatically increasing the throughput. Here we evaluate the
performance of different aperture codes for spectroscopy of
weak, incoherent sources. © 2006 Optical Society of
America.},
Doi = {10.1364/fio.2006.fmb5},
Key = {fds280209}
}
@article{fds280210,
Author = {Fernandez, C and Guenther, BD and Gehm, ME and Brady, DJ and Sullivan,
ME},
Title = {Longwave infrared (LWIR) coded aperture dispersive
spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We describe a static aperture-coded, dispersive longwave
infrared (LWIR) spectrometer that uses a microbolometer
array as the detector plane. We present experimental results
of absorption spectroscopy for a variety of sources. © 2006
Optical Society of America.},
Key = {fds280210}
}
@article{fds280211,
Author = {Portnoy, AD and Gehm, ME and Brady, DJ},
Title = {Pushbroom hyperspectral imaging with a coded
aperture},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
url = {http://dx.doi.org/10.1364/fio.2006.fmb2},
Abstract = {We describe a hyperspectral camera which operates by
translating a scene across the entrance of a coded aperture
spectrometer. This applies a sequence of unique codes to the
image, allowing full reconstruction of the datacube. © 2006
Optical Society of America.},
Doi = {10.1364/fio.2006.fmb2},
Key = {fds280211}
}
@article{fds280212,
Author = {Feller, SD and Gehm, ME and Brady, DJ and Hsieh, C and Momtahan, O and Adibi, A},
Title = {Multiple order coded aperture (MOCA) spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
url = {http://dx.doi.org/10.1364/fio.2006.fmb4},
Abstract = {We introduce a Multiple Order Coded Aperture (MOCA)
spectrometer that uses a crossdispersive hologram and a
coded aperture to achieve improved spectral range over
traditional dispersive spectrometers at comparable
resolution. © 2006 OSA.},
Doi = {10.1364/fio.2006.fmb4},
Key = {fds280212}
}
@article{fds280213,
Author = {Fernandez, C and Guenther, BD and Gehm, ME and Brady, DJ and Sullivan,
ME},
Title = {Longwave infrared (LWIR) coded aperture dispersive
spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
Abstract = {We describe a static aperture-coded, dispersive longwave
infrared (LWIR) spectrometer that uses a microbolometer
array as the detector plane. We present experimental results
of absorption spectroscopy for a variety of sources. © 2006
Optical Society of America.},
Key = {fds280213}
}
@article{fds280214,
Author = {Fernandez, C and Guenther, BD and Gehm, ME and Brady, DJ and Sullivan,
ME},
Title = {Longwave infrared (LWIR) coded aperture dispersive
spectrometer},
Journal = {Optics Infobase Conference Papers},
Year = {2006},
Month = {January},
url = {http://dx.doi.org/10.1364/fio.2006.jsua10},
Abstract = {We describe a static aperture-coded, dispersive longwave
infrared (LWIR) spectrometer that uses a microbolometer
array as the detector plane. We present experimental results
of absorption spectroscopy for a variety of sources. © 2006
Optical Society of America.},
Doi = {10.1364/fio.2006.jsua10},
Key = {fds280214}
}
@article{fds280311,
Author = {McCain, ST and Gehm, ME and Wang, Y and Pitsianis, NP and Brady,
DJ},
Title = {Raman spectroscopy: Large-aperture raman spectroscopy for
quantitative chemometrics},
Journal = {Optics and Photonics News},
Volume = {17},
Number = {12},
Pages = {42},
Year = {2006},
Month = {January},
ISSN = {1047-6938},
url = {http://dx.doi.org/10.1364/opn.17.12.000042},
Abstract = {The creation of an inexpensive, mechanically robust,
large-aperture Raman spectrometry for quantitative
chemometrics is presented. The traditional slit aperture is
replaced with a large-aperture pattern of significant
complexity, which converts the instrument into a
computational sensor. A specific patter is chosen to have
mathematical properties that optimized the performance of
this processing step. The pattern is designed so that each
column of the pattern acts as a virtual slit, measuring the
spectrum at high resolution and combining its result with
all the other columns to increase the number of collected
photons. A data model is constructed, which use a standard
partial least-squares algorithm by using measurements made
on liquid tissue phantoms spiked with varying concentrations
of ethanol. The successful quantitative measurements in a
scattering medium represents a significant step on the path
toward the eventual clinical application of Raman
spectroscopy.},
Doi = {10.1364/opn.17.12.000042},
Key = {fds280311}
}
@article{9364190,
Author = {Badieirostami, M and Momtahan, O and Adibi, A and Brady,
DJ},
Title = {A Tandem Fabry-Perot volume hologram spectrometer with high
resolution},
Journal = {Conference Proceedings Lasers and Electro Optics Society
Annual Meeting Leos},
Pages = {290-291},
Publisher = {IEEE},
Address = {Montreal, Que., Canada},
Year = {2006},
Month = {January},
ISSN = {1092-8081},
url = {http://dx.doi.org/10.1109/LEOS.2006.279062},
Keywords = {Fabry-Perot interferometers;holography;optical design
techniques;spectrometers;},
Abstract = {We have designed a compact spectrometer by cascading a
simple Fabry-Perot etalon and a volume hologram. The volume
hologram expands the limited spectral range of the
Fabry-Perot and the combination of both elements results in
a powerful spectrometer with good two-dimensional
spatial-spectral diversity in the output plane. © 2006
IEEE.},
Doi = {10.1109/LEOS.2006.279062},
Key = {9364190}
}
@article{06059670349,
Author = {Fang, J-S and Hao, Q and Brady, DJ and Shankar, M and Guenther, BD and Pitsianis, NP and Hsu, KY},
Title = {Path-dependent human identification using a pyroelectric
infrared sensor and fresnel lens arrays.},
Journal = {Optics Express},
Volume = {14},
Number = {2},
Pages = {609-624},
Year = {2006},
Month = {January},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/opex.14.000609},
Keywords = {Lenses;Cost effectiveness;Alarm systems;Parameter
estimation;Spectrum analysis;Principal component
analysis;},
Abstract = {This paper presents a design and development of a low power
consumption, and low cost, human identification system using
a pyroelectric infrared (PIR) sensor whose visibility is
modulated by a Fresnel lens array. The optimal element
number of the lens array for the identification system was
investigated and the experimental results suggest that the
lens array with more elements can yield a better performance
in terms of identification and false alarm rates. The other
parameters of the system configuration such as the height of
sensor location and sensor-to-object distance were also
studied to improve spectral distinctions among sensory data
of human objects. The identification process consists of two
parts: training and testing. For the data training, we
employed a principal components regression (PCR) method to
cluster data with respect to different registered objects at
different speed levels. The feature data of different
objects walking along the same path in training yet at
random speeds are then tested against the pre-trained
clusters to decide whether the target is registered, and
which member of the registered group it is.},
Doi = {10.1364/opex.14.000609},
Key = {06059670349}
}
@article{070210353272,
Author = {Brady, DJ},
Title = {Micro-optics and megapixels},
Journal = {Optics and Photonics News},
Volume = {17},
Number = {11},
Pages = {24-29},
Publisher = {The Optical Society},
Year = {2006},
Month = {January},
ISSN = {1047-6938},
url = {http://dx.doi.org/10.1364/OPN.17.11.000024},
Keywords = {Measurement theory;Spectrometers;Image sensors;Goggles;Algorithms;Diffraction;},
Abstract = {New sampling and measurement methods are proposed for
spectrometers and imagers that are shrinking the size and
boosting the performance of optical devices for several
applications. Costs are reduced because less plastic, glass,
and metal is used in each instrument and because smaller
components are easier to incorporate in automated
manufacturing processes. Emerging demands for compact
instruments include low-profile infrared goggles, low-power
ground sensor arrays, integrated sensors, and biomedical
devices. It is believed that compressive sampling implements
image and spectral compression in the measurement layer and
assumes advanced signal inference algorithms in
post-detection processing. Operators need to have high
quality micro-optics operating near the diffraction limit
and high fidelity nonlinear image estimation algorithms to
make multichannel sampling work.},
Doi = {10.1364/OPN.17.11.000024},
Key = {070210353272}
}
@article{063110038801,
Author = {Fang, Jian-Shuen and Hao, Qi and Brady, David J. and Guenther, Bob D. and Hsu, Ken Y.},
Title = {Real-time human identification using a pyroelectric infrared
detector array and hidden Markov models},
Journal = {Optics Express},
Volume = {14},
Number = {15},
Pages = {6643 - 6658},
Year = {2006},
url = {http://dx.doi.org/10.1364/OE.14.006643},
Keywords = {Piezoelectric devices;Pattern recognition;Infrared
detectors;Markov processes;Statistical methods;Motion
estimation;},
Abstract = {This paper proposes a real-time human identification system
using a pyroelectric infrared (PIR) detector array and
hidden Markov models (HMMs). A PIR detector array with
masked Fresnel lens arrays is used to generate digital
sequential data that can represent a human motion feature.
HMMs are trained to statistically model the motion features
of individuals through an expectation-maximization (EM)
learning process. Human subjects are recognized by
evaluating a set of new feature data against the trained
HMMs using the maximum-likelihood (ML) criterion. We have
developed a prototype system to verify the proposed method.
Sensor modules with different numbers of detectors and
different sampling masks were tested to maximize the
identification capability of the sensor system. © 2006
Optical Society of America.},
Key = {063110038801}
}
@article{4258374,
Author = {Chen, AG-S and Brady, DJ},
Title = {Surface-stabilized holography in an azo-dye-doped liquid
crystal},
Journal = {Opt. Lett. (Usa)},
Volume = {17},
Number = {17},
Pages = {1231-1233},
Publisher = {The Optical Society},
Year = {2006},
url = {http://dx.doi.org/10.1364/OL.17.001231},
Keywords = {holography;liquid crystal devices;nematic liquid
crystals;solid-state phase transformations;},
Abstract = {Holograms are recorded by a 514-nm laser polarized parallel
to the molecular director in an azo-dye-doped nematic liquid
crystal. For some surface treatments, the recorded holograms
persist in the dark. For glass surfaces, exposure to light
polarized normal to the molecular director erases the
hologram. The hologram also vanishes when the sample is
heated across the nematic to isotropic phase transition but
reappears when the sample is cooled back to the nematic
phase. The dynamics and strength of this effect depend
strongly on the surface treatment of the sample
cell},
Doi = {10.1364/OL.17.001231},
Key = {4258374}
}
@article{063810119326,
Author = {Brady, DJ and Gehm, ME and Pitsianis, N and Sun, X},
Title = {Compressive sampling strategies for integrated
microspectrometers},
Journal = {Proceedings of Spie the International Society for Optical
Engineering},
Volume = {6232},
Pages = {62320},
Publisher = {SPIE},
Address = {Kissimmee, FL, United States},
Year = {2006},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.666124},
Keywords = {Spectroscopic analysis;Sensitivity analysis;Digital
storage;Algorithms;Signal processing;Mathematical
models;Problem solving;Constraint theory;},
Abstract = {We consider compressive sensing in the context of optical
spectroscopy. With compressive sensing, the ratio between
the number of measurements and the number of estimated
values is less than one, without compromising the fidelity
in estimation. A compressive sensing system is composed of a
measurement subsystem that maps a signal to digital data and
an inference algorithm that maps the data to a signal
estimate. The inference algorithm exploits both the
information captured in the measurement and certain a priori
information about the signals of interest, while the
measurement subsystem provides complementary,
signal-specific information at the lowest sampling rate
possible. Codesign of the measurement strategies, the model
of a priori information, and the inference algorithm is the
central problem of system design. This paper describes
measurement constraints specific to optical spectrometers,
inference models based on physical or statistical
characteristics of the signals, as well as linear and
nonlinear reconstruction algorithms. We compare the fidelity
of sampling and inference strategies over a family of
spectral signals.},
Doi = {10.1117/12.666124},
Key = {063810119326}
}
@article{06259945946,
Author = {Gehm, ME and McCain, ST and Pitsianis, NP and Brady, DJ and Potuluri, P and Sullivan, ME},
Title = {Static two-dimensional aperture coding for multimodal,
multiplex spectroscopy},
Journal = {Applied Optics},
Volume = {45},
Number = {13},
Pages = {2965-2974},
Year = {2006},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16639444},
Keywords = {Encoding (symbols);Spectrum analysis;Optimization;Optical
resolving power;Spectrometers;},
Abstract = {We propose a new class of aperture-coded spectrometer that
is optimized for the spectral characterization of diffuse
sources. The instrument achieves high throughput and high
spectral resolution by replacing the slit of conventional
dispersive spectrometers with a more complicated spatial
filter. We develop a general mathematical framework for
deriving the required aperture codes and discuss several
appealing code families. Experimental results validate the
performance of the instrument. © 2006 Optical Society
of America.},
Doi = {10.1364/AO.45.002965},
Key = {06259945946}
}
@article{06289986776,
Author = {McCain, ST and Gehm, ME and Wang, Y and Pitsianis, NP and Brady,
DJ},
Title = {Coded aperture Raman spectroscopy for quantitative
measurements of ethanol in a tissue phantom},
Journal = {Applied Spectroscopy},
Volume = {60},
Number = {6},
Pages = {663-671},
Year = {2006},
ISSN = {0003-7028},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16808868},
Keywords = {Raman spectroscopy;Tissue;Optimization;Spectrometers;Regression
analysis;Multiplexing;},
Abstract = {Coded aperture spectroscopy allows for sources of large
etendue to be efficiently coupled into dispersive
spectrometers by replacing the traditional input slit with a
patterned mask. We describe a coded aperture spectrometer
optimized for Raman spectroscopy of diffuse sources, (e.g.,
tissue). We provide design details of the Raman system,
along with quantitative estimation results for ethanol at
non-toxic levels in a lipid tissue phantom. With 60 mW of
excitation power at 808 nm, leave-one-out and blind
cross-validation of partial least squares (PLS) regression
models achieve r 2 > 0.98. Leave-one-out cross-validation
demonstrates prediction errors of less than or equal 15% at
the common legal limit for intoxication (17.4 mmol/L = 0.08%
by vol) and the best blind cross-validation achieves less
than or equal 12% error at this concentration. © 2006
Society for Applied Spectroscopy.},
Doi = {10.1366/000370206777670693},
Key = {06289986776}
}
@article{06199862382,
Author = {Potuluri, P and Sullivan, ME and Wang, Y and Brady,
DJ},
Title = {Diffuse spectroscopy for inhomogeneous metal nanoparticle
assays},
Journal = {Proceedings of Spie the International Society for Optical
Engineering},
Volume = {6080},
Pages = {60800},
Publisher = {SPIE},
Address = {San Jose, CA, United States},
Year = {2006},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.645319},
Keywords = {Nanostructured materials;Spectroscopic analysis;Computation
theory;Biosensors;Controlled drug delivery;},
Abstract = {We describe a compact computational spectroscopy platform
optimized for molecular recognition using metal nanoparticle
assays. The objective is motivated by the urgent need for
low-cost, portable and high-throughput sensors for
point-of-care (POC) clinical diagnostics. Nanoparticle based
sensing has been successfully demonstrated for diagnosis and
monitoring of infectious diseases, drug discovery,
proteomics, and biological agent detection. Molecular
binding on the nanoparticle surface is transuded into an
optical signal by modification of the nanoparticle
extinction spectrum (via a shift in Localized Surface
Plasmon Resonance) or by modification of the molecular
scattering spectrum (via Surface Enhanced Raman Scattering).
Translating a nanoparticle -based molecular recognition
system into a functional miniature hand-held biosensor
requires spectrometer designs optimized to large area
nanoparticle assays and integrated spectral filtering to
improve the signal specificity. Large population sampling
with small population sensitivity is essential to highly
sensitive nanoparticle assay analysis. We describe a
multimodal multiplex spectroscopy (MMS) platform that
samples the spectral response of up to 106 populations of
10-100 nanoparticles in parallel. The advantages of MMS
approach include: extremely high signal throughput due to
its large aperture and high resolution with small form
factor. We will demonstrate a nanoparticle biosensor
platform based on MMS. Ultimately, a fully integrated
functional miniature nanoparticle based biosensor for real
time disease diagnosis in whole blood assays can be
realized.},
Doi = {10.1117/12.645319},
Key = {06199862382}
}
@article{fds280306,
Author = {Guo, J and Portnoy, A and Brady, DJ},
Title = {Diffraction-limited impulse response image reconstruction
with a single imaging pixel},
Journal = {2005 Osa Topical Meeting on Information Photonics, Ip
2005},
Year = {2005},
Month = {December},
Abstract = {In this paper, we will discuss two techniques to reconstruct
diffraction-limited impulse response images by sub-pixel
shifting the photodetector array and measuring the signal
from a specific large area photodetector pixel. © 2005
Optical Society of America.},
Key = {fds280306}
}
@article{070510403827,
Author = {Linnehan, R and Brady, D and Schindler, J and Perlovsky, L and Rangaswamy, M},
Title = {Multi-dimensional aperture design and analysis for SAR using
the Cramér-rao theorem},
Journal = {Ieee Camsap 2005 First International Workshop on
Computational Advances in Multi Sensor Adaptive
Processing},
Volume = {2005},
Pages = {4-7},
Publisher = {IEEE},
Address = {Puerto Vallarta, Mexico},
Year = {2005},
Month = {December},
url = {http://dx.doi.org/10.1109/CAMAP.2005.1574169},
Keywords = {Computer simulation;Error analysis;Optimization;Synthetic
aperture radar;},
Abstract = {We are applying the Cramér-Rao theorem to synthetic
aperture radar (SAR) processing in order to establish flight
paths that permit height estimation and minimize errors in
reflectivity measurements. The Cramér-Rao bound (CRB)
establishes a lower bound on the error variance of unbiased
estimates. Error bounds are developed for multi-dimensional
synthetic apertures that improve the overall performance and
efficiency of monostatic, single-pass SAR missions. A
computationally efficient means for the design and analysis
of SAR waveforms is proposed using simulated scattering
models that are limited in size. A comparison made with the
error bounds for standard SAR show that estimates of
scatterer range and cross-range positions are sufficiently
accurate for multi-dimensional aperture SAR, even with the
additional estimator for height. © 2005
IEEE.},
Doi = {10.1109/CAMAP.2005.1574169},
Key = {070510403827}
}
@article{06029636001,
Author = {Brady, DJ and Feldman, M and Pitsianis, N and Guo, JP and Portnoy, A and Fiddy, M},
Title = {Compressive optical montage photography},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {5907},
Pages = {1-7},
Publisher = {SPIE},
Address = {San Diego, CA, United States},
Year = {2005},
Month = {December},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.613213},
Keywords = {Imaging systems;Optical resolving power;Holography;Image
processing;Algorithms;Optical sensors;Optimization;Birefringence;},
Abstract = {The Compressive Optical MONTAGE Photography Initiative
(COMP-I) is an initiative under DARPA's MONTAGE program. The
goals of COMP-I are to produce 1 mm thick visible imaging
systems and 5 mm thick IR systems without compromising
pixel-limited resolution. Innovations of COMP-I include
focal-plane coding, block-wise focal plane codes,
birefringent, holographic and 3D optical elements for focal
plane remapping and embedded algorithms for image formation.
In addition to meeting MONTAGE specifications for sensor
thickness, focal plane coding enables a reduction in the
transverse aperture size, physical layer compression of
multispectral and hyperspectral data cubes, joint optical
and electronic optimization for 3D sensing, tracking,
feature-specific imaging and conformal array
deployment.},
Doi = {10.1117/12.613213},
Key = {06029636001}
}
@article{05469475385,
Author = {Pitsianis, NP and Brady, DJ and Sun, X},
Title = {Sensor-layer image compression based on the quantized cosine
transform},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {5817},
Pages = {250-257},
Address = {Orlando, FL, United States},
Year = {2005},
Month = {November},
ISSN = {0277-786X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000231343200025&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Keywords = {Image sensors;Vector quantization;Cosine transforms;Imaging
systems;Image quality;},
Abstract = {We introduce a novel approach for compressive coding at the
sensor layer for an integrated imaging system. Compression
at the physical layer reduces the measurements-to-pixels
ratio and the data volume for storage and transmission,
without confounding image estimation or analysis. We
introduce a particular compressive coding scheme based on
the quantized Cosine transform (QCT) and the corresponding
image reconstruction scheme. The QCT is restricted on the
ternary set {-1, 0, 1} for economic implementation with a
focal plane optical pixel mask. Combined with the
reconstruction scheme, the QCT-based coding is shown
favorable over existing coding schemes from the coded
aperture literature, in terms of both reconstruction quality
and photon efficiency.},
Doi = {10.1117/12.605659},
Key = {05469475385}
}
@article{05439428807,
Author = {Shankar, M and Burchett, J and Feller, SD and Jones, B and Swagart, R and Guenther, BD and Brady, DJ},
Title = {Biometric tracking with coded pyroelectric sensor
clusters},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {5796},
Pages = {174-185},
Publisher = {SPIE},
Address = {Orlando, FL, United States},
Year = {2005},
Month = {October},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.606557},
Keywords = {Codes (symbols);Thermal effects;Pyroelectricity;Lenses;Arrays;},
Abstract = {Human bodies are very good heat sources with peak emission
wavelength of about 9μm. We use pyroelectric detectors that
are differential in nature to detect human motion by their
heat emissions. Coded Fresnel lens arrays create boundaries
in space which helps to localize the human motion as well as
classification. We design and implement a low-cost biometric
tracking system using off-the-shelf components. We
demonstrate tracking and classification using sensor
clusters of dual-element pyroelectric detectors with coded
Fresnel lens arrays.},
Doi = {10.1117/12.606557},
Key = {05439428807}
}
@article{fds280308,
Author = {Kraus, CL and Salazar, NC and Mitchell, JR and Florin, WD and Guenther,
B and Brady, D and Swartzwelder, SH and White, AM},
Title = {Inconsistencies between actual and estimated blood alcohol
concentrations in a field study of college students: do
students really know how much they drink?},
Journal = {Alcoholism, Clinical and Experimental Research},
Volume = {29},
Number = {9},
Pages = {1672-1676},
Year = {2005},
Month = {September},
ISSN = {0145-6008},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16205367},
Abstract = {BACKGROUND: Alcohol use by college students is commonly
measured through the use of surveys. The validity of such
data hinge on the assumption that students are aware of how
much alcohol they actually consume. Recent studies call this
assumption into question. Students tend to overestimate the
appropriate sizes of standard drinks, suggesting that they
might underestimate how much alcohol they consume. If this
is true, then students' actual blood alcohol concentrations
(BACs) should be higher than BACs estimated based on
self-report data. The present study examined this issue
METHODS: Breathalyzer readings and self-reported drinking
data were collected from 152 college students during the
fall of 2004. Estimated BACs were calculated by means of a
standard formula, and the relation between actual and
estimated BACs was examined. Factors contributing to
discrepancies between the two values were identified
RESULTS: Estimated BAC levels were significantly higher, not
lower, than breath BAC measures. The accuracy of estimated
BACs decreased as the number of drinks and amount of time
spent drinking increased. Being male and drinking only beer
predicted greater accuracy of estimated BACs CONCLUSIONS:
Although laboratory data suggest that students underestimate
how much they drink, the hypothesis was not supported by
data collected in the field. It appears that students might
actually overestimate rather than underestimate their levels
of consumption when surveyed in the midst of a night of
drinking. The findings corroborate observations made by
other researchers and suggest that the findings of
laboratory studies on college drinking do not necessarily
extend to real-world settings.},
Doi = {10.1097/01.alc.0000179205.24180.4a},
Key = {fds280308}
}
@article{05329282812,
Author = {Zheng, Y and Brady, DJ and Sullivan, ME and Guenther,
BD},
Title = {Fiber-optic localization by geometric space coding with a
two-dimensional gray code.},
Journal = {Applied Optics},
Volume = {44},
Number = {20},
Pages = {4306-4314},
Year = {2005},
Month = {July},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16045218},
Keywords = {Fiber optics;Image coding;Computational geometry;Binary
codes;Cost effectiveness;Data communication
equipment;},
Abstract = {With the objective of monitoring motion within a room, we
segment the two-dimensional (2D) floor space into discrete
cells and encode each cell with a binary code word generated
by a fiber. We design a set of k-neighbor-local codes to
localize an extended object and, particularly when k = 2,
employ a 2D gray code to localize a human by tracking his or
her footsteps. Methods for implementing the codes in a fiber
web are discussed, and we demonstrate the experimental
result with the fiber mat. The observed system performance
confirms the theoretical analysis. The space coding
technique is a promising low-cost candidate not only for
human tracking but also for other applications such as human
gait analysis.},
Doi = {10.1364/ao.44.004306},
Key = {05329282812}
}
@article{fds280149,
Author = {Feller, SD and Burchett, JB and Hao, Q and Fang, JS and Shankar, M and Guenther, BD and Brady, DJ},
Title = {Human characterization and tracking using pyroelectric
sensors},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
ISSN = {2162-2701},
Abstract = {A network of common pyroelectric motion sensors that can
track and identify human targets has been developed using
low-cost, commercially available components. Significantly
cheaper than deploying infrared imag- ing systems and
considerably more advanced than typical motion sensing
systems, this system consists of a small number of sensor
nodes distributed across a medium sized room. Each node
contain up to eight pyroelectric detectors and provides
limited computation and communication capabil- ities. These
detectors use structured lenslets to extract frequency com-
ponents of targets for classification and the location and
orientation of the sensors is used to track targets as they
move through the space. This system has demonstrated
multiple target tracking and the ability to dif- ferentiate
between multiple people. © 2005 OSA/OSHS
2005.},
Key = {fds280149}
}
@article{fds280165,
Author = {Guo, J and Portnoy, A and Brady, DJ},
Title = {Diffraction-limited impulse response image reconstruction
with a single imaging pixel},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {In this paper, we will discuss two techniques to reconstruct
diffraction-limited impulse response images by sub-pixel
shifting the photodetector array and measuring the signal
from a specific large area photodetector pixel. © 2005
Optical Society of America.},
Key = {fds280165}
}
@article{fds280166,
Author = {Brady, DJ and Fiddy, MA and Shahid, U and Suleski,
TJ},
Title = {Compressive optical MONTAGE photography initiative: Noise
and error analysis},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {Image resolution is usually considered to be proportional to
the focal plane sampling rate. However, as a result of
Papoulis's generalized sampling theory [1], it is possible
to reconstruct bandlimited images from sub-Nyquist sampled
data provided multiple channels of such data are measured,
with each set suitably transformed to permit the computation
of the original image. The COMP-I program uses focal plane
coding to set sub-band sampling characteristics. Analysis
and simulation of this approach to errors and noise is
presented. © 2005 Optical Society of America.},
Key = {fds280166}
}
@article{fds280167,
Author = {Pitsianis, NP and Brady, DJ and Sun, X},
Title = {The quantized cosine transform for sensor-layer image
compression},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {We introduce a compressive encoding at the sensor layer
based on the quantized cosine transform. Compression at the
physical layer of integrated imaging systems reduces the
measurements-to-pixels ratio, the data volume and
accelerates image estimation. © 2005 Optical Society of
America.},
Key = {fds280167}
}
@article{fds280168,
Author = {Pitsianis, NP and Brady, DJ and Sun, X},
Title = {The quantized cosine transform for sensor-layer image
compression},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {We introduce a compressive encoding at the sensor layer
based on the quantized cosine transform. Compression at the
physical layer of integrated imaging systems reduces the
measurements-to-pixels ratio, the data volume and
accelerates image estimation. © 2005 Optical Society of
America.},
Key = {fds280168}
}
@article{fds280169,
Author = {Shankar, M and Jones, DB and Swagart, RG and Burchett, JB and Guenther,
BD and Feller, SD and Brady, DJ},
Title = {Large area pyroelectric motion tracking system},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {Simple pyroelectric detectors and structured apertures are
used to monitor motion in an area and report location and
velocity of objects moving through the monitored area. ©
2005 OSA/COSI 2005.},
Key = {fds280169}
}
@article{fds280170,
Author = {Mait, JN and Prather, DW and Brady, DJ},
Title = {Diffractive generation of non-redundant images for a
multi-aperture, thin, high-resolution camera},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {We have designed a diffractive element capable of generating
shift-encoded images for a thin, multiplexed optical imaging
system. We present simulations that validate the use of the
element for high resolution imaging and preliminary
experimental results of diffractive image replication. ©
2005 Optical Society of America.},
Key = {fds280170}
}
@article{fds280171,
Author = {Hsieh, C and Momtahan, O and Karbaschi, A and Adibi, A and Brady,
DJ},
Title = {Compact spectral diversity filters for diffuse source
spectroscopy using spherical beam volume
holograms},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {We describe a new class of compact spectral diversity
filters implemented using spherical beam volume holograms.
Spectral diversity is improved by rotation multiplexing
technique. Diffuse source spectroscopy enabled by using
Fourier transform architecture is demonstrated. © 2005
Optical Society of America.},
Key = {fds280171}
}
@article{fds280172,
Author = {Guo, J and Portnoy, A and Brady, DJ},
Title = {Diffraction-limited impulse response image reconstruction
with a single imaging pixel},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {In this paper, we will discuss two techniques to reconstruct
diffraction-limited impulse response images by sub-pixel
shifting the photodetector array and measuring the signal
from a specific large area photodetector pixel. © 2005
Optical Society of America.},
Key = {fds280172}
}
@article{fds280173,
Author = {Peters, AE and Gehm, ME and Guenther, BD and Brady,
DJ},
Title = {Multiplex design for high-performance microspectrometers},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {The volume of spectrometers can be drastically reduced
through the use of multiplex measurement. Reductions of 3-5
orders of magnitude are possible. This has the potential to
drastically effect manufacturing and deployment costs.
©2005 Optical Society of America.},
Key = {fds280173}
}
@article{fds280174,
Author = {Gehm, ME and McCain, ST and Wang, Y and Pitsianis, NP and Brady,
DJ},
Title = {Multimodal, multiplex Raman spectrometer for weak,
incoherent sources},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {Raman spectroscopy in bio-materials is complicated by
fluorescence and scattering. We have developed a multimodal,
multiplex spectrometer that overcomes these difficulties. We
are currently constructing a second generation prototype for
in-vivo Raman spectroscopy of tissue. © 2005 Optical
Society of America.},
Key = {fds280174}
}
@article{fds280179,
Author = {Portnoy, AD and Guo, J and Pitsianis, NP and Guenther, B and Brady, DJ and Te Kolste and RD and Feldman, MR and Fiddy, MA and Suleski,
TJ},
Title = {Multi-aperture visible high resolution thin
imager},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {We have designed and built a multi-aperture thin imager
using a lenslet array and a CCD imager. The thickness of the
imager is significantly reduced. We will present
experimental results that demonstrate high resolution
imaging. © 2005 Optical Society of America.},
Key = {fds280179}
}
@article{fds280180,
Author = {Gibbons, RC and Gilstrap, JA and Mait, JN and Prather, DW and Guo, J and Brady, DJ},
Title = {Design of a thin multi-aperture infrared
imager},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {We have designed a thin, multiplexed infrared imaging system
that uses a diffractive element for generating shift-encoded
images in each aperture. We present preliminary experimental
results that demonstrate imager performance. © 2005 Optical
Society of America.},
Key = {fds280180}
}
@article{fds280181,
Author = {Fiddy, MA and Suleski, TJ and Brady, DJ and Pitsianis,
NP},
Title = {Compressive sampling for feature specific compact
imagers},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {We investigate the use of estimation methods with
multi-aperture imaging hardware that are noise robust and
able to provide high resolution images from limited
measurements. © 2005 Optical Society of
America.},
Key = {fds280181}
}
@article{fds280182,
Author = {Shankar, M and Burchett, JB and Feller, SD and Guenther, BD and Brady,
DJ},
Title = {Human motion tracking system using coded Fresnel lens
arrays},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {We have designed and developed a low-cost human motion
tracking system using pyroelectric detectors and coded
Fresnel lens arrays. We have deployed sensor clusters
implementing an 8x8 Hadamard code variant and will
demonstrate motion tracking. © 2005 Optical Society of
America.},
Key = {fds280182}
}
@article{fds280206,
Author = {Gehm, ME and Brady, DJ},
Title = {Tomographic hyperspectral imaging without a
missing-cone},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
url = {http://dx.doi.org/10.1364/fio.2005.ftuaa2},
Abstract = {We describe a hyperspectral imager combining coded aperture
spectroscopy and tomographic spatial reconstruction. The
throughput of the system is improved compared to scanning
techniques while avoiding the missing-cone problem common to
many spectral tomographic approaches. © 2005 Optical
Society of America.},
Doi = {10.1364/fio.2005.ftuaa2},
Key = {fds280206}
}
@article{05068829094,
Author = {Hsieh, C and Momtahan, O and Karbaschi, A and Adibi, A and Sullivan, ME and Brady, DJ},
Title = {Role of recording geometry in the performance of spectral
diversity filters with spherical beam volume
holograms.},
Journal = {Optics Letters},
Volume = {30},
Number = {2},
Pages = {186-188},
Year = {2005},
Month = {January},
ISSN = {0146-9592},
url = {http://dx.doi.org/10.1364/OL.30.000186},
Keywords = {Holograms;Optical recording;Spectrometers;Holography;Optical
materials;Light transmission;Bandwidth;Calibration;},
Abstract = {We present experimental demonstrations of spectral diversity
filters with spherical beam volume holograms for multimodal
multiplex spectroscopy. Major properties of filters under
diffuse-light illumination are discussed. The comparisons of
spectral diversity between the transmission geometry
holograms and the reflection geometry holograms are also
studied. The results show that there is a trade-off between
the degree of the spatial coherence of the source and the
spectral diversity of the filter. We also conclude that the
reflection geometry holograms have better spectral diversity
and less sensitivity to the spatial coherence of the
source.},
Doi = {10.1364/ol.30.000186},
Key = {05068829094}
}
@article{fds340700,
Author = {McCain, ST and Gehm, ME and Wang, Y and Pitsianis, NP and Sullivan, ME and Brady, DJ},
Title = {Multimodal, multiplex, Raman spectroscopy of alcohol in
diffuse, fluorescent media},
Journal = {Optics Infobase Conference Papers},
Year = {2005},
Month = {January},
Abstract = {Optical diagnostics in biological materials are hindered by
fluorescence and scattering. We have developed a multimodal,
multiplex, coded-aperture Raman spectrometer to detect
alcohol in a lipid tissue phantom solution. ©2005 Optical
Society of America.},
Key = {fds340700}
}
@article{05429421140,
Author = {Cull, EC and Gehm, ME and McCain, ST and Guenther, BD and Brady,
DJ},
Title = {Multimodal optical spectrometers for remote chemical
detection},
Journal = {Proceedings of Spie the International Society for Optical
Engineering},
Volume = {5778},
Number = {PART I},
Pages = {376-382},
Publisher = {SPIE},
Address = {Orlando, FL, United States},
Year = {2005},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.606574},
Keywords = {Optical systems;Remote sensing;Raman scattering;Throughput;Spectrum
analyzers;},
Abstract = {We have developed a class of aperture coding schemes for
Remote Raman Spectrometers (RRS) that remove the traditional
trade-off between throughput and spectral resolution. As a
result, the size of the remote interrogation region can be
driven by operational, rather than optical considerations.
We present theoretical arguments on the performance of these
codes and present data from where we have utilized these
codes in other spectroscopy efforts.},
Doi = {10.1117/12.606574},
Key = {05429421140}
}
@article{06109742883,
Author = {Cull, EC and Gehm, ME and Guenther, BD and Brady,
DJ},
Title = {Standoff raman spectroscopy system for remote chemical
detection},
Journal = {Proceedings of Spie the International Society for Optical
Engineering},
Volume = {5994},
Pages = {59940},
Publisher = {SPIE},
Address = {Boston, MA, United States},
Year = {2005},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.626170},
Keywords = {Remote sensing;Data reduction;Throughput;},
Abstract = {We have developed a class of aperture coding schemes for
Remote Raman Spectrometers (RRS) that remove the traditional
trade-off between throughput and spectral resolution. As a
result, the size of the remote interrogation region can be
driven by operational, rather than optical considerations.
In this paper we present the design of our coded-aperture
standoff spectroscopy system as well as experimental data
collected while making remote measurements.},
Doi = {10.1117/12.626170},
Key = {06109742883}
}
@article{05519599055,
Author = {McCain, ST and Gehm, ME and Wang, Y and Pitsianis, NP and Sullivan, ME and Brady, DJ},
Title = {Multimodal, multiplex, Raman spectroscopy of alcohol in
diffuse, fluorescent media},
Journal = {Progress in Biomedical Optics and Imaging Proceedings of
Spie},
Volume = {5864},
Pages = {1-9},
Address = {Munich, Germany},
Year = {2005},
ISSN = {1605-7422},
url = {http://dx.doi.org/10.1117/12.632934},
Keywords = {Alcohols;Diffusers (fluid);Fluorescence;Medical
imaging;Biological materials;Tissue;},
Abstract = {Optical diagnostics in biological materials are hindered by
fluorescence and scattering. We have developed a multimodal,
multiplex, coded-aperture Raman spectrometer to detect
alcohol in a lipid tissue phantom solution. © 2005 SPIE
and OSA.},
Doi = {10.1117/12.632934},
Key = {05519599055}
}
@article{04528737781,
Author = {Burchett, JB and Shankar, M and Feller, SD and Brady,
DJ},
Title = {Efficient human pose tracking using multiplex
sensing},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {5403},
Number = {PART 2},
Pages = {418-426},
Publisher = {SPIE},
Address = {Orlando, FL, United States},
Year = {2004},
Month = {December},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.546788},
Keywords = {Position measurement;Human engineering;Decision
making;Mapping;Multiplexing;Infrared detectors;},
Abstract = {We design and calibrate an efficient human detection system,
capable of detecting and tracking a single person while
minimizing the number of required sensors. Our infrared
detectors have a 2 meter range and a 250ms rise/fall time.
We sample their signal using an MSP430F149 microprocessor,
correlate the results to reference patterns, and collect the
binary decisions of each sensor on a workstation wirelessly.
We modulate the optical field of the detectors by
introducing selectively opaque reference structures into
their optical path. Segmenting the physical space into
signature cells enables direct measurement of source
configuration. Brute force determination of the mapping is
prohibitively expensive; we propose a method to estimate
this mapping and predict signatures for every source
position by observing signatures along prescribed tracks
through the physical space.},
Doi = {10.1117/12.546788},
Key = {04528737781}
}
@article{05108871831,
Author = {Hsieh, C and Momtahan, O and Karbaschi, A and Adibi, A and Sullivan, ME and Brady, DJ},
Title = {Implementation of spectral diversity filters using spherical
beam volume holograms},
Journal = {Conference Proceedings Lasers and Electro Optics Society
Annual Meeting Leos},
Volume = {1},
Pages = {192-193},
Address = {Rio Grande, Puerto Rico},
Year = {2004},
Month = {December},
Keywords = {Holograms;Signal filtering and prediction;Sensors;Multiplexing;Fourier
transforms;Light transmission;Reflection;Optical
collimators;Coherent light;},
Abstract = {We present experimental demonstrations of spectral diversity
filters using spherical beam volume holograms. Major
properties of filters under collimated and diffuse light
will be presented. We also show rotation multiplexing can
improve the spectral diversity. © 2004 IEEE/LEOS.},
Key = {05108871831}
}
@article{05038792937,
Author = {Potuluri, P and Gehm, M and Sullivan, M and Brady,
D},
Title = {Measurement-efficient optical wavemeters.},
Journal = {Optics Express},
Volume = {12},
Number = {25},
Pages = {6219-6229},
Year = {2004},
Month = {December},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19488267},
Keywords = {Optical systems;Spectrometers;Photodetectors;Monochromators;Semiconducting
gallium arsenide;Infrared radiation;Interferometers;Dense
wavelength division multiplexing;Communication
systems;Fourier transforms;},
Abstract = {We describe a method for efficiently determining the
wavelength of a monochromatic source and provide an
experimental proof-of-concept. The photomeasurement
efficiency for a wavemeter can be written as eta(N,q) = (1 +
logqN)/m, where N is the number of spectral channels, q is
the number of distinguishable output levels per
photodetector, and m is the actual number of
photomeasurements made. An implementation is developed that
achieves a theoretical efficiency of eta(N,q) = 1. The
proof-of-concept experiment achieves efficiencies eta =
O(1), where the deviation from theory is attributable to
well-known optical effects and should be correctable in
future versions.},
Doi = {10.1364/opex.12.006219},
Key = {05038792937}
}
@article{05058813020,
Author = {Momtahan, O and Hsieh, CR and Karbaschi, A and Adibi, A and Sullivan,
ME and Brady, DJ},
Title = {Spherical beam volume holograms for spectroscopic
applications: modeling and implementation.},
Journal = {Applied Optics},
Volume = {43},
Number = {36},
Pages = {6557-6567},
Year = {2004},
Month = {December},
ISSN = {1559-128X},
url = {http://dx.doi.org/10.1364/AO.43.006557},
Keywords = {Charge coupled devices;Reduction;Spectrometers;Spectroscopic
analysis;Signal detection;Theorem proving;Computer
simulation;},
Abstract = {The spherical beam volume hologram, recorded by a plane wave
and a spherical beam, is investigated for spectroscopic
applications in detail. It is shown that both the diffracted
and the transmitted beam can be used for spectroscopy when
the hologram is read with a collimated beam. A new method is
introduced and used for analysis of the spherical beam
volume hologram that can be extended for analysis of
arbitrary holograms. Experimental results are consistent
with the theoretical study. It is shown that the spherical
beam volume hologram can be used in a compact spectroscopic
configuration when the transmitted beam is monitored. Also,
on the basis of the properties of the spherical beam
hologram, the response of a hologram recorded by a plane
wave and an arbitrary pattern is predicted. The information
can be used to optimize holographic spectrometer
design.},
Doi = {10.1364/ao.43.006557},
Key = {05058813020}
}
@article{04318295138,
Author = {Brady, DJ and Pitsianis, NP and Sun, X},
Title = {Reference structure tomography.},
Journal = {Journal of the Optical Society of America
A},
Volume = {21},
Number = {7},
Pages = {1140-1147},
Year = {2004},
Month = {July},
ISSN = {1084-7529},
url = {http://www.ncbi.nlm.nih.gov/pubmed/15260245},
Keywords = {Tomography;Mathematical models;Light modulation;Image
coding;Image analysis;Image sensors;Modal analysis;Image
segmentation;Image reconstruction;Image quality;Geometry;Computer
simulation;},
Abstract = {Reference structure tomography (RST) uses multidimensional
modulations to encode mappings between radiating objects and
measurements. RST may be used to image source-density
distributions, estimate source parameters, or classify
sources. The RST paradigm permits scan-free multidimensional
imaging, data-efficient and computation-efficient source
analysis, and direct abstraction of physical features. We
introduce the basic concepts of RST and illustrate the use
of RST for multidimensional imaging based on a geometric
radiation model.},
Doi = {10.1364/josaa.21.001140},
Key = {04318295138}
}
@article{04428408769,
Author = {Karbaschi, A and Hsieh, C and Momtahan, O and Adibi, A and Sullivan, M and Brady, D},
Title = {Qualitative demonstration of spectral diversity filtering
using spherical beam volume holograms.},
Journal = {Optics Express},
Volume = {12},
Number = {13},
Pages = {3018-3024},
Year = {2004},
Month = {June},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/OPEX.12.003018},
Keywords = {Holograms;Diffraction gratings;Laser beams;Thin
films;Optical collimators;Light sources;Spectrometers;Spectroscopic
analysis;Vectors;},
Abstract = {We investigate the feasibility of designing spectral
diversity filters using spherical beam volume holograms. Our
experimental results qualitatively show the separation of
the information of different incident wavelength channels
using spherical beam volume holograms. The major trade-off
in using these holograms is between the degree of spatial
spectral diversity and the number of allowed spatial modes
(or the divergence angle) of the incident
beam.},
Doi = {10.1364/opex.12.003018},
Key = {04428408769}
}
@article{8280815,
Author = {Sendaula, MH and Biswas, SK and Teter, JP and Brady,
DJ},
Title = {A control system for a hybrid linear actuator for a flush
deck hatch},
Journal = {Proceedings of the American Control Conference},
Volume = {3},
Pages = {2051-2056},
Address = {Boston, MA, USA},
Year = {2004},
Month = {January},
ISSN = {0743-1619},
url = {http://dx.doi.org/10.23919/acc.2004.1383762},
Keywords = {control system synthesis;electric actuators;feedback;linear
motors;magnetostrictive devices;ships;},
Abstract = {This paper presents the control system design in the
development of a hybrid linear actuator for opening the
flush deck hatch CV/CVN ship class. We present a simple
feedback control system for the hatch opening, which is
described by a nonlinear model. The hybrid linear actuator
consists of magnetostrictive thrusters and high force
electric linear motors segments ganged together to drive a
load shaft through of sets of self-locking, magnetically
activated clutches. The control system is based on
trajectory following method with a simple
feedback-linearizing loop. Simulation results show excellent
performance of the closed loop system.},
Doi = {10.23919/acc.2004.1383762},
Key = {8280815}
}
@article{06139790960,
Author = {Momtahan, O and Hsieh, CR and Karbaschi, A and Adibi, A and Sullivan,
ME and Brady, DJ},
Title = {Spherical beam holograms for spectroscopic applications:
Modeling and implementation},
Journal = {Osa Trends in Optics and Photonics Series},
Volume = {96 A},
Pages = {431-432},
Address = {Washington, DC, United States},
Year = {2004},
Month = {January},
ISSN = {1094-5695},
Keywords = {Spectroscopic analysis;Diffraction;},
Abstract = {A new approach for analyzing spherical beam holograms is
presented and tested. This method describes the diffraction
effect in spherical beam holograms and its application in
spectroscopy. The theoretical results are verified by
experiments. © 2003 Optical Society of America.},
Key = {06139790960}
}
@article{8386023,
Author = {Potuluri, P. and Gehm, M.E. and Sullivan, M.E. and Brady,
D.J.},
Title = {Measurement-efficient optical wavemeters},
Journal = {Opt. Express (USA)},
Volume = {12},
Number = {25},
Year = {2004},
Keywords = {laser variables measurement;photodetectors;photometers;photometry;wavemeters;},
Abstract = {We describe a method for efficiently determining the
wavelength of a monochromatic source and provide an
experimental proof-of-concept. The photomeasurement
efficiency for a wavemeter can be written as η(N,q) = (1
+ log<sub>q</sub>N)/m, where N is the number of spectral
channels, q is the number of distinguishable output levels
per photodetector, and m is the actual number of
photomeasurements made. An implementation is developed that
achieves a theoretical efficiency of η(N,q) = 1. The
proof-of-concept experiment achieves efficiencies η =
O(1), where the deviation from theory is attributable to
well-known optical effects and should be correctable in
future versions},
Key = {8386023}
}
@article{8263061,
Author = {Astratov, V.N. and Ashili, S.P. and Franchak, J.P. and Saltzman, A.J. and Sullivan, M.E. and Brady, D.J. and Filin,
S.V. and Puzynin, A.I. and Samoilov, V.N. and Moroz,
A.},
Title = {Polycrystalline low index contrast opals: Towards novel
multimodal spectroscopy of diffusive sources of
light},
Journal = {Conference on Lasers and Electro-Optics (CLEO)},
Volume = {vol.2},
Pages = {2 pp. vol.2 -},
Address = {San Francisco, CA, USA},
Year = {2004},
Keywords = {light scattering;light sources;optical materials;visible
spectroscopy;},
Abstract = {It is shown that polycrystalline low index contrast opals
with submillimeter domains provide spatio-spectral diversity
of scattering images that can be used for measuring the
wavelengths of diffusive sources of light with nanometer
accuracy},
Key = {8263061}
}
@article{8154724,
Author = {Karbaschi, A. and Hsieh, C. and Momtahan, O. and Adibi, A. and Sullivan, M.E. and Brady, D.J.},
Title = {Qualitative demonstration of spectral diversity filtering
using spherical beam volume holograms},
Journal = {Opt. Express (USA)},
Volume = {12},
Number = {13},
Year = {2004},
Keywords = {holographic gratings;optical filters;spectrometers;},
Abstract = {We investigate the feasibility of designing spectral
diversity filters using spherical beam volume holograms. Our
experimental results qualitatively show the separation of
the information of different incident wavelength channels
using spherical beam volume holograms. The major trade-off
in using these holograms is between the degree of spatial
spectral diversity and the number of allowed spatial modes
(or the divergence angle) of the incident
beam},
Key = {8154724}
}
@article{fds280396,
Author = {Basty, S and Neifeld, MA and Brady, D and Kraut, S},
Title = {Nonlinear estimation for interferometric
imaging},
Journal = {Optics Communications},
Volume = {228},
Number = {4-6},
Pages = {249-261},
Publisher = {Elsevier BV},
Year = {2003},
Month = {December},
url = {http://dx.doi.org/10.1016/j.optcom.2003.10.004},
Abstract = {We conduct a comparative study between two types of imaging
systems for distant point sources. One is a conventional
focal plane system and the other, a multiplex system based
on a rotational shearing interferometer (RSI). The RSI
produces linear fringes in response to each object point
source, which offers functional advantages over the
conventional system. A nonlinear algorithm is developed for
estimating fringe parameters in an RSI that performs better
than traditional Fourier methods; while an existing
nonlinear algorithm is modified for use with the
conventional imager. Intensity and position estimation
performance of the two imaging systems is characterized
using both traditional as well as nonlinear estimation in
the presence of noise. In additive white gaussian noise
dominated imaging, we find that the RSI is always inferior
to the conventional imager by a factor that is approximately
the square root of the number of detectors. However, the two
imaging systems are comparable in the shot-noise limit.
Simulated performances for a single monochromatic source are
reported for the shot-noise limited case. The
super-resolution ability of the nonlinear algorithms is
studied with two monochromatic sources at various
separations. The nonlinear estimator is also applied to
polychromatic point sources and the simultaneous estimation
of spatial and spectral data for the RSI is demonstrated. ©
2003 Elsevier B.V. All rights reserved.},
Doi = {10.1016/j.optcom.2003.10.004},
Key = {fds280396}
}
@article{04278253664,
Author = {Sinha, A and Brady, D},
Title = {Size and shape recognition using measurement statistics and
random 3D reference structures.},
Journal = {Optics Express},
Volume = {11},
Number = {20},
Pages = {2606-2618},
Year = {2003},
Month = {October},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.11.002606},
Keywords = {Pattern recognition;Lenses;Radon;Charge coupled
devices;Mapping;Probability density function;Statistical
methods;Fourier transforms;Algorithms;},
Abstract = {Three dimensional (3D) reference structures segment source
spaces based on whether particular source locations are
visible or invisible to the sensor. A lensless 3D reference
structure based imaging system measures projections of this
source space on a sensor array. We derive and experimentally
verify a model to predict the statistics of the measured
projections for a simple 2D object. We show that the
statistics of the measurement can yield an accurate estimate
of the size of the object without ever forming a physical
image. Further, we conjecture that the measured statistics
can be used to determine the shape of 3D objects and present
preliminary experimental measurements for 3D shape
recognition.},
Doi = {10.1364/oe.11.002606},
Key = {04278253664}
}
@article{7909776,
Author = {Potuluri, P and Xu, M and Brady, D},
Title = {Imaging with random 3D reference structures.},
Journal = {Optics Express},
Volume = {11},
Number = {18},
Pages = {2134-2141},
Year = {2003},
Month = {September},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.11.002134},
Keywords = {image reconstruction;image segmentation;image
sensors;optical computing;optical images;optical
sensors;},
Abstract = {We describe a sensor system based on 3D 'reference
structures' which implements a mapping from a 3D source
volume on to a 2D sensor plane. The reference structure used
here is a random three dimensional distribution of
polystyrene beads. We show how this bead structure spatially
segments the source volume and present some simple
experimental results of 2D and 3D imaging.},
Doi = {10.1364/oe.11.002134},
Key = {7909776}
}
@article{04278253696,
Author = {Gopinathan, U and Brady, D and Pitsianis, N},
Title = {Coded apertures for efficient pyroelectric motion
tracking.},
Journal = {Optics Express},
Volume = {11},
Number = {18},
Pages = {2142-2152},
Year = {2003},
Month = {September},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.11.002142},
Keywords = {Optical sensors;Infrared radiation;Infrared
detectors;Imaging systems;Frequency response;Vectors;Mapping;Error
analysis;},
Abstract = {Coded apertures may be designed to modulate the visibility
between source and measurement spaces such that the position
of a source among N resolution cells may be discriminated
using logarithm of N measurements. We use coded apertures as
reference structures in a pyroelectric motion tracking
system. This sensor system is capable of detecting source
motion in one of the 15 cells uniformly distributed over a
1.6m x 1.6m domain using 4 pyroelectric detectors.},
Doi = {10.1364/oe.11.002142},
Key = {04278253696}
}
@article{7909775,
Author = {Xu, Z and Wang, Z and Sullivan, ME and Brady, DJ and Foulger, SH and Adibi,
A},
Title = {Multimodal multiplex spectroscopy using photonic
crystals},
Journal = {Opt. Express (Usa)},
Volume = {11},
Number = {18},
Pages = {2126-2133},
Year = {2003},
Month = {September},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.11.002126},
Keywords = {focal planes;image resolution;light coherence;light
transmission;micro-optics;photonic crystals;spectral
analysis;visible spectrometers;visible spectroscopy;},
Abstract = {Spatio-spectral transmission patterns induced on low
coherence fields by disordered photonic crystals can be used
to construct optical spectrometers. Experimental results
suggest that 1 to 10 nm resolution multimodal spectrometers
for diffuse source analysis may be constructed using a
photonic crystal mounted on a focal plane array. The
relative independence of spatial and spectral modal response
in photonic crystals enables high efficiency spectral
analysis of diffuse sources},
Doi = {10.1364/oe.11.002126},
Key = {7909775}
}
@article{04278253471,
Author = {Potuluri, P and Gopinathan, U and Adleman, J and Brady,
D},
Title = {Lensless sensor system using a reference
structure.},
Journal = {Optics Express},
Volume = {11},
Number = {8},
Pages = {965-974},
Year = {2003},
Month = {April},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/oe.11.000965},
Keywords = {Geometrical optics;Optical design;Imaging systems;Optical
resolving power;X rays;Photodiodes;Correlation
methods;Matrix algebra;Mathematical transformations;},
Abstract = {We describe a reference structure based sensor system for
tracking the motion of an object. The reference structure is
designed to implement a Hadamard transformation over a range
of angular perspectives. We implemented a reference
structure with an angular resolution of 5(o) and a field of
view of 40(o).},
Doi = {10.1364/oe.11.000965},
Key = {04278253471}
}
@article{04498702415,
Author = {Brady, DJ},
Title = {3D Optical Elements for Computational Sensors},
Journal = {Osa Trends in Optics and Photonics Series},
Volume = {88},
Pages = {1949-1951},
Address = {Baltimore, MD, United States},
Year = {2003},
Month = {January},
ISBN = {9781557528209},
ISSN = {1094-5695},
Keywords = {Photons;Crystals;Optical filters;Optical systems;Data
reduction;Computational complexity;},
Abstract = {3D Optical Elements for Computational Sensors. We discuss
geometric segmentation of optical fields by volume optical
elements and 3D photonic circuits and describe example
systems. 3D elements include volume holograms, geometric
filters and microcavity arrays. Photonic crystals and
heterogeneous integration may further extend volume
capabilities.},
Key = {04498702415}
}
@article{7988579,
Author = {Sinha, A. and Brady, D.J.},
Title = {Size and shape recognition using measurement statistics and
random 3D reference structures},
Journal = {Opt. Express (USA)},
Volume = {11},
Number = {20},
Year = {2003},
Keywords = {CCD image sensors;feature extraction;image
recognition;},
Abstract = {Three dimensional (3D) reference structures segment source
spaces based on whether particular source locations are
visible or invisible to the sensor. A lensless 3D reference
structure based imaging system measures projections of this
source space on a sensor array. We derive and experimentally
verify a model to predict the statistics of the measured
projections for a simple 2D object. We show that the
statistics of the measurement can yield an accurate estimate
of the size of the object without ever forming a physical
image. Further, we conjecture that the measured statistics
can be used to determine the shape of 3D objects and present
preliminary experimental measurements for 3D shape
recognition},
Key = {7988579}
}
@article{04278253694,
Author = {Xu, Zhaochun and Wang, Zhanglei and Sullivan, Michael E. and Brady, David J. and Foulger, Stephen H. and Adibi,
Ali},
Title = {Multimodal multiplex spectroscopy using photonic
crystals},
Journal = {Optics Express},
Volume = {11},
Number = {18},
Pages = {2126 - 2133},
Year = {2003},
Keywords = {Crystals;Multiplexing;Diffusion;Color;Vectors;Least squares
approximations;Modal analysis;Spectroscopic
analysis;},
Abstract = {Spatio-spectral transmission patterns induced on low
coherence fields by disordered photonic crystals can be used
to construct optical spectrometers. Experimental results
suggest that 1-10 nm resolution multimodal spectrometers for
diffuse source analysis may be constructed using a photonic
crystal mounted on a focal plane array. The relative
independence of spatial and spectral modal response in
photonic crystals enables high efficiency spectral analysis
of diffuse sources. © 2003 Optical Society of
America.},
Key = {04278253694}
}
@article{04278253695,
Author = {Potuluri, Prasant and Xu, Mingbo and Brady, David
J.},
Title = {Imaging with random 3D reference structures},
Journal = {Optics Express},
Volume = {11},
Number = {18},
Pages = {2134 - 2141},
Year = {2003},
Keywords = {Polystyrenes;Imaging systems;Optical systems;Mapping;Correlation
methods;Optical microscopy;},
Abstract = {We describe a sensor system based on 3D 'reference
structures' which implements a mapping from a 3D source
volume on to a 2D sensor plane. The reference structure used
here is a random three dimensional distribution of
polystyrene beads. We show how this bead structure spatially
segments the source volume and present some simple
experimental results of 2D and 3D imaging. © 2003
Optical Society of America.},
Key = {04278253695}
}
@article{fds280395,
Author = {Feller, SD and Zheng, Y and Cull, E and Brady, DJ},
Title = {Tracking and imaging humans on heterogeneous infrared sensor
arrays for law enforcement applications},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4708},
Pages = {212-221},
Publisher = {SPIE},
Year = {2002},
Month = {December},
url = {http://dx.doi.org/10.1117/12.479310},
Abstract = {We present a plan for the integration of geometric
constraints in the source, sensor and analysis levels of
sensor networks. The goal of geometric analysis is to reduce
the dimensionality and complexity of distributed sensor data
analysis so as to achieve real-time recognition and response
to significant events. Application scenarios include
biometric tracking of individuals, counting and analysis of
individuals in groups of humans and distributed sentient
environments. We are particularly interested in using this
approach to provide networks of low cost point detectors,
such as infrared motion detectors, with complex imaging
capabilities. By extending the capabilities of simple
sensors, we expect to reduce the cost of perimeter and site
security applications.},
Doi = {10.1117/12.479310},
Key = {fds280395}
}
@article{03077362854,
Author = {Kraut, S and Gallicchio, J and Brady, D},
Title = {High-resolution direction finding and scan-free spectrum
estimation with rotational-shear interferometric sensor
arrays},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4789},
Pages = {267-274},
Publisher = {SPIE},
Address = {Seattle, WA, United States},
Year = {2002},
Month = {December},
url = {http://dx.doi.org/10.1117/12.459013},
Keywords = {Fourier transform infrared spectroscopy;Charge coupled
devices;Image quality;Optical resolving power;Prisms;Light
interference;Coherent light;Approximation theory;Computer
simulation;},
Abstract = {In this paper we investigate the application of a
rotational-shear interferometer, toward the problem of
simultaneously estimating the directions of well-localized
sources, and their spectral profiles. Rotational shear makes
possible the acquisition of a spectrum estimate, without the
mechanical scan required in using a Michelson interferometer
in Fourier-transform spectroscopy. The spectrum and angle
estimates are obtained computationally. The interferometric
data enables the application of super-resolution
direction-finding techniques commonly used in radar and
sonar array processing.},
Doi = {10.1117/12.459013},
Key = {03077362854}
}
@article{03097371853,
Author = {Cull, EC and Kowalski, DP and Burchett, JB and Feller, SD and Brady,
DJ},
Title = {Three-dimensional imaging with the Argus sensor
array},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4864},
Pages = {211-222},
Publisher = {SPIE},
Address = {Boston, MA, United States},
Year = {2002},
Month = {December},
url = {http://dx.doi.org/10.1117/12.454932},
Keywords = {Image sensors;Cameras;Parallel processing
systems;Computerized tomography;Image compression;Feature
extraction;},
Abstract = {The Argus project uses an array of computers and cameras as
a means of investigating telepresence and real-time
three-dimensional imaging. In this paper we will briefly
discuss telepresence from an information flow and
visualization perspective. The paper also includes a
detailed description of the Argus hardware and a software
layer developed to manage the imaging and computational
resources. MPEG-2 and feature extraction will be described
as parallel compression systems for the Argus camera
array.},
Doi = {10.1117/12.454932},
Key = {03097371853}
}
@article{02487249966,
Author = {Tumbar, R and Brady, DJ},
Title = {Sampling field sensor with anisotropic fan-out},
Journal = {Applied Optics},
Volume = {41},
Number = {31},
Pages = {6621-6636},
Publisher = {The Optical Society},
Year = {2002},
Month = {November},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/AO.41.006621},
Keywords = {Interferometers;Phase shift;Optical testing;Birefringence;Vibrations
(mechanical);Real time systems;Anisotropy;},
Abstract = {We describe a new common-path, phase-shift, and shearing
interferometric device capable of single-shot detection of
optical phase profiles. It samples the input field and uses
birefringent plates to fan out phase-shifted copies of the
samples in the empty space between them. The phase shifts
are given by the thickness of the plates and not by the
relative position of the components, as in classical
interferometers. This makes the device insensitive to
vibrations. We recorded repeatability better than λ/100,
even though strong shocks were applied to the air table in
proximity to the system. We recorded better than λ/1000
repeatability under quiet conditions and estimated the
accuracy to be better than λ/3000 at the shot-noise limit.
In addition, the device is compact and easy to integrate in
a variety of setups that require the measurement of optical
phase profiles. © 2002 Optical Society of
America.},
Doi = {10.1364/AO.41.006621},
Key = {02487249966}
}
@article{02467204401,
Author = {Brady, DJ and Rahman, Z-U},
Title = {Integrated analysis and design of analog and digital
processing in imaging systems: introduction to the feature
issue.},
Journal = {Applied Optics},
Volume = {41},
Number = {29},
Pages = {6049},
Year = {2002},
Month = {October},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12389972},
Abstract = {This feature presents themes arising from the Integrated
Computational Imaging Systems topical meeting sponsored by
the OSA in fall 2001. These themes revolve around joint
design of digital and analog image processing to improve the
specificity and efficiency of optical image
sensors.},
Doi = {10.1364/ao.41.006049},
Key = {02467204401}
}
@article{02467204402,
Author = {Marks, DL and Stack, RA and Brady, DJ},
Title = {Digital refraction distortion correction with an astigmatic
coherence sensor.},
Journal = {Applied Optics},
Volume = {41},
Number = {29},
Pages = {6050-6054},
Year = {2002},
Month = {October},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/ao.41.006050},
Keywords = {Optical sensors;Coherent light;Distortion (waves);Energy
dissipation;Aberrations;},
Abstract = {We demonstrate the sensing and correction of an isoplanatic
refractive distortion (not lens aberrations), using the
complete measurement of the partially coherent field in an
aperture that the previously described astigmatic coherence
sensor provides. Isoplanatic distortions, and in general
distortions that do not cause energy loss, maintain the
orthogonality of the coherent modes. We use the fact that a
common distortion will occur to all coherent modes to
separate the distortion from the source behind it, rather
than requiring a reference source at a different wavelength.
Digital deconvolution was performed on the full
four-dimensional partially coherent field for simultaneously
computing the distortion and the source intensity
distribution.},
Doi = {10.1364/ao.41.006050},
Key = {02467204402}
}
@article{fds280289,
Author = {Osborne, MD and Brady, DJ},
Title = {The room is long and narrow},
Journal = {Research in Science Education},
Volume = {32},
Number = {2},
Pages = {163-170},
Year = {2002},
Month = {January},
ISSN = {0157-244X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000179949400004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {In this paper we analyse some of our experiences with peer
review and argue that the process should be rethought.
Rather than a gate-keeping device, the ideological function
should be acknowledged as well as acknowledging that the
true (idealistic) purpose of publishing is to air and
develop new ideas - in effect to evolve the community. Given
this, peer review as a process would be better thought of as
helping authors to develop their ideas and to share them.
Such a process involves attempting to understand what an
author is trying to do and helping her achieve her goal. It
is critically constructive and creative rather than
destructive/deconstructive. In recognising this we
articulate the "true" purpose of the peer review process and
of participating in it - or at least the democratic purpose
for which it was conceived. This involves enabling divergent
opinions to be heard and this in turn enables the evolution
of the field from within, for the danger is if evolution
does not come from within it is imposed from without. ©
2002 Kluwer Academic Publishers.},
Doi = {10.1023/a:1016021910755},
Key = {fds280289}
}
@article{02507274930,
Author = {Feller, SD and Cull, E and Kowalski, D and Farlow, K and Burchett, J and Adleman, J and Lin, C and Brady, DJ},
Title = {Tracking and imaging humans on heterogeneous infrared sensor
array for tactical applications},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4743},
Pages = {168-175},
Publisher = {SPIE},
Address = {Orlando, FL, United States},
Year = {2002},
Month = {January},
url = {http://dx.doi.org/10.1117/12.448394},
Keywords = {Arrays;Tracking (position);Infrared imaging;Cameras;Costs;},
Abstract = {We recently implemented a heterogeneous network of infrared
motion detectors and an infrared camera for the detection,
localization, tracking, and identification of human targets.
The network integrates dense deployments of low cost motion
sensors for target tracking with sparse deployments of image
sensors for target registration. Such networks can be used
in tactical applications for local and distributed perimeter
and site security. Rapid deployments for crisis management
may be of particular interest. This paper focuses
particularly on the need for applications that deal with
relatively dense and complex source fields such as crowds
move through sensor spaces. © Society of Photo-Optical
Instrumentation Engineers.},
Doi = {10.1117/12.448394},
Key = {02507274930}
}
@article{02256986844,
Author = {Brady, DJ},
Title = {Multiplex sensors and the constant radiance
theorem.},
Journal = {Optics Letters},
Volume = {27},
Number = {1},
Pages = {16-18},
Year = {2002},
Month = {January},
ISSN = {0146-9592},
url = {http://dx.doi.org/10.1364/ol.27.000016},
Keywords = {Signal to noise ratio;Multiplexing;Eigenvalues and
eigenfunctions;Probability distributions;Fourier
transforms;Optical systems;Spectroscopic
analysis;},
Abstract = {Coherent mode representation of the cross-spectral density
is used to derive a modal analog of the constant radiance
theorem with general applicability to linear optical
systems. The theorem is used to consider the relationship
between spatial detector geometry and multiplexing
capacity.},
Doi = {10.1364/ol.27.000016},
Key = {02256986844}
}
@article{02417134155,
Author = {Rittgers, AM and Morrison, RL and Stack, RA and Brady,
DJ},
Title = {Tomographic processing on wireless ground sensor
networks},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4393},
Pages = {122-128},
Publisher = {SPIE},
Address = {Orlando, FL, United States},
Year = {2001},
Month = {December},
url = {http://dx.doi.org/10.1117/12.441261},
Keywords = {Wireless telecommunication systems;Imaging
techniques;Tomography;Interferometry;Space
surveillance;Military operations;Real time systems;Tracking
(position);Video cameras;Computer vision;Algorithms;},
Abstract = {New opportunities for battlefield surveillance and modeling
are unfolding with the advent of smart sensors linked via
digital wireless networks. One exciting prospect is the use
of tomographic techniques in order to create real-time
three-dimensional modeling and analysis of the environment
that is immediately accessible to battlefield forces. We
have developed a small-scale ground sensor network for this
application. We discuss initial deployment of this network
as a tracking system.},
Doi = {10.1117/12.441261},
Key = {02417134155}
}
@article{fds330752,
Author = {Bouchereau, F and Brady, D and Lanzl, C},
Title = {Multipath delay estimation using a superresolution
PN-correlation method},
Journal = {Ieee Transactions on Signal Processing},
Volume = {49},
Number = {5},
Pages = {938-949},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2001},
Month = {May},
url = {http://dx.doi.org/10.1109/78.917798},
Abstract = {This paper addresses the problem of high-resolution
estimation of a multipath channel delay profile. We propose
several improvements to the so-called superresolution
pseudo-noise sequence correlation method (SPM) and analyze
its performance on time-varying channels. SPM is based on
the multiple signal classification (MUSIC) algorithm, which
requires decorrelation of the multipath echoes. The proposed
improvements enable SPM-based delay estimation in the
presence of narrowband interference, and they reduce the
necessary transmission window while preserving multipath
echo decorrelation. These improvements are analyzed and are
applied to underwater acoustic experimental
data.},
Doi = {10.1109/78.917798},
Key = {fds330752}
}
@article{03317573724,
Author = {Marks, DL and Stack, R and Johnson, AJ and Brady, DJ and Munson,
DC},
Title = {Cone-beam tomography with a digital camera},
Journal = {Applied Optics},
Volume = {40},
Number = {11},
Pages = {1795-1805},
Publisher = {The Optical Society},
Year = {2001},
Month = {April},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/AO.40.001795},
Keywords = {Digital devices;Cameras;X rays;Image reconstruction;Opacity;Electromagnetic
wave diffraction;Lighting;Algorithms;},
Abstract = {We show that x-ray computer tomography algorithms can be
applied with minimal alteration to the three-dimensional
reconstruction of visible sources. Diffraction and opacity
affect visible systems more severely than x-ray systems. For
camera-based tomography, diffraction can be neglected for
objects within the depth of field. We show that, for convex
objects, opacity has the effect of windowing the angular
observation range and thus blurring the reconstruction. For
concave objects, opacity leads to nonlinearity in the
transformation from object to reconstruction and may cause
multiple objects to map to the same reconstruction. In x-ray
tomography, the contribution of an object point to a line
integral is independent of the orientation of the line. In
optical tomography, however, a Lambertian assumption may be
more realistic. We derive an expression for the blur
function ~the patch response! for a Lambertian source. We
present experimental results showing cone-beam
reconstruction of an incoherently illuminated opaque object.
© 2001 Optical Society of America.},
Doi = {10.1364/AO.40.001795},
Key = {03317573724}
}
@article{fds280394,
Author = {Osborne, MD and Brady, DJ},
Title = {Constructing a space for developing a rich understanding of
science through play},
Journal = {Journal of Curriculum Studies},
Volume = {33},
Number = {5},
Pages = {511-524},
Publisher = {Informa UK Limited},
Year = {2001},
Month = {January},
ISSN = {0022-0272},
url = {http://dx.doi.org/10.1080/00220270120863},
Doi = {10.1080/00220270120863},
Key = {fds280394}
}
@article{01526775706,
Author = {Brady, DJ},
Title = {Multiplex optics for visual image processing},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4388},
Pages = {97-102},
Publisher = {SPIE},
Address = {Orlando,FL},
Year = {2001},
Month = {January},
url = {http://dx.doi.org/10.1117/12.438246},
Keywords = {Image sensors;Imaging systems;Signal filtering and
prediction;Spectrum analysis;},
Abstract = {Multiplex optical systems are designed to mix information
channels on sensors. This paper considers the use of
multiplex sensors to embed scene analysis in the optical
layer of imaging systems. The goals of embedded analysis are
to reduce the system data and processing load and to improve
analytic accuracy by low-level filtering. We show
specifically that filtering on the cross spectral density
during detection allows the construction of sensors that
integrate spatio-spectral patterns from specific volumes and
that coded illumination patterns can structure the radiated
cross spectrum to enable digital focusing on particular
source characteristics.},
Doi = {10.1117/12.438246},
Key = {01526775706}
}
@article{6980126,
Author = {Potuluri, P and Fetterman, MR and Brady, DJ},
Title = {High depth of field microscopic imaging using an
interferometric camera},
Journal = {Optics Express},
Volume = {8},
Number = {11},
Pages = {624-630},
Publisher = {The Optical Society},
Year = {2001},
Month = {January},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/OE.8.000624},
Keywords = {cameras;image sensors;light interferometry;optical design
techniques;optical microscopes;},
Abstract = {We describe the design or a microscope combining rotational
shear interferometer (RSI)-based coherence imaging with an
objective lens to simultaneously obtain high numerical
aperture and high depth of field imaging. We present
experimental results showing the operation of this
instrument. ©2001 Optical Society of America.},
Doi = {10.1364/OE.8.000624},
Key = {6980126}
}
@article{01336620404,
Author = {Morrison, R and Brady, DJ and Rittgers, A and Stack,
R},
Title = {Wireless integrated sensing, processing and display networks
for site security},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4232},
Pages = {352-358},
Publisher = {SPIE},
Address = {Boston, MA},
Year = {2001},
Month = {January},
url = {http://dx.doi.org/10.1117/12.417550},
Keywords = {Sensor data fusion;Integrated circuit layout;Mobile
computing;Information management;Image analysis;Java
programming language;Flash memory;Interfaces
(computer);},
Abstract = {We consider data management on ad hoc networks of sensing
and processing nodes. We describe the construction of simple
nodes from off the shelf components (PC 104 single board
computers with flash memory, video capture cards and 802.llb
wireless interfaces). We describe a Java interface to
controlling these nodes and accessing images and image
processing algorithms. We demonstrate target tracking across
nodes and the potential for heterogeneous sensor
types.},
Doi = {10.1117/12.417550},
Key = {01336620404}
}
@article{7373420,
Author = {Liang, T.K. and Tsang, H.K. and Roberts, S.W. and Brady,
D.J. and Harpin, A. and Drake, J. and Asghari,
M.},
Title = {Measurement of dispersion in a silicon waveguide at 1.5
μm},
Journal = {Technical Digest. CLEO/Pacific Rim 2001. 4th Pacific Rim
Conference on Lasers and Electro-Optics (Cat.
No.01TH8557)},
Volume = {vol.2},
Pages = {722 - 3},
Address = {Chiba, Japan},
Year = {2001},
url = {http://dx.doi.org/10.1109/CLEOPR.2001.971163},
Keywords = {integrated optics;Mach-Zehnder interferometers;optical
communication equipment;optical dispersion;optical
testing;optical waveguides;silicon;wavelength division
multiplexing;},
Abstract = {We report for the first time measurements of the dispersion
coefficient in a silicon waveguide at 1.5 μm wavelength.
The total dispersion was found to be only -9.1
fs/[nm.cm]},
Key = {7373420}
}
@article{04328303913,
Author = {Potuluri, P. and Fetterman, M.R. and Brady,
D.J.},
Title = {High depth of field microscopic imaging using an
interferometric camera},
Journal = {Optics Express},
Volume = {8},
Number = {11},
Pages = {624 - 630},
Year = {2001},
Keywords = {Interferometers;Cameras;Imaging systems;Mirrors;Throughput;Tomography;Fourier
transforms;Integral equations;Approximation
theory;Algorithms;},
Abstract = {We describe the design or a microscope combining rotational
shear interferometer (RSI)-based coherence imaging with an
objective lens to simultaneously obtain high numerical
aperture and high depth of field imaging. We present
experimental results showing the operation of this
instrument. ©2001 Optical Society of
America.},
Key = {04328303913}
}
@article{01025528026,
Author = {Brady, DJ},
Title = {Optical processing for 3D digital imaging},
Journal = {Conference Proceedings Lasers and Electro Optics Society
Annual Meeting Leos},
Volume = {1},
Pages = {114},
Address = {Rio Grande},
Year = {2000},
Month = {December},
url = {http://dx.doi.org/10.1109/LEOS.2000.890700},
Keywords = {Image quality;Two dimensional;Communication channels
(information theory);Image reconstruction;Three
dimensional;},
Abstract = {Alternative models for source coding are presented and shown
to impact transformation transfer and conventional image
quality measures. System performance when conventional image
formation is unnecessary is demonstrated.},
Key = {01025528026}
}
@article{03427672396,
Author = {Marks, DM and Stack, RA and Brady, DJ},
Title = {Astigmatic coherence sensor for digital imaging},
Journal = {Optics Letters},
Volume = {25},
Number = {23},
Pages = {1726-1728},
Publisher = {The Optical Society},
Year = {2000},
Month = {December},
ISSN = {0146-9592},
url = {http://dx.doi.org/10.1364/OL.25.001726},
Keywords = {Digital signal processing;Coherent light;Interferometers;Sampling;},
Abstract = {We present a novel sensor that measures the entire spatial
coherence function within an aperture by use of a variable
astigmatic lens. This sensor permits digital capture and
processing of partially coherent fields. We demonstrate the
sensor by sampling and computing the coherent modes of a
three-dimensional incoherent source. © 2000 Optical Society
of America.},
Doi = {10.1364/OL.25.001726},
Key = {03427672396}
}
@article{fds330753,
Author = {Brady, D and Kocic, M and Miller, AW and Karger, BL},
Title = {A maximum-likelihood base caller for DNA
sequencing.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {47},
Number = {9},
Pages = {1271-1280},
Year = {2000},
Month = {September},
url = {http://dx.doi.org/10.1109/10.867962},
Abstract = {The procedures used to sequence the human genome involve the
electrophoretic separation of mixtures of dioxyribonucleic
acid (DNA) fragments tagged with reporting groups, usually
fluorescent dyes. Each fluorescent pulse which arrives from
an optical detector corresponds to a nucleotide (base) in
the DNA sequence, and the subsequent process of base
detection is known as base calling. Generating longer and
more accurate sequences in the base-calling process will
reduce the high cost of DNA sequencing. This paper presents
an automated base-calling algorithm, referred to as
maximum-likelihood base caller (MLB), which is based on
maximum likelihood equalization for digital communication
channels. Based on 125 experimental datasets, MLB averaged
up to 40% fewer errors than the widely used ABI base caller
from the Applied Biosystems Division of PE Corporation.
MLB's accuracy rivaled that of another well-known base
caller, Phred, surpassing it on datasets with high
background noise.},
Doi = {10.1109/10.867962},
Key = {fds330753}
}
@article{03317572765,
Author = {Brady, D and Neifeld, MA},
Title = {Information theory in optoelectronic systems: Introduction
to the feature},
Journal = {Applied Optics},
Volume = {39},
Number = {11},
Pages = {1679-1680},
Publisher = {The Optical Society},
Year = {2000},
Month = {April},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/AO.39.001679},
Keywords = {Information theory;Digital signal processing;Communication
systems;Systems analysis;Computational complexity;},
Abstract = {There has been an explosion of recent interest concerning
information theory in optoelectronic (OE) systems. This
interest has been motivated in part by (1) the accelerating
deployment of OE components into digital systems, (2) the
blurring of the analog-digital interface within many OE
applications, and (3) the increasing sophistication and
complexity of computational tools. These trends are being
driven by revolutionary improvements in both OE devices and
electronic processors together with increasing demand for
high-speed and high-capacity solutions. This feature
addresses the application of information- and
communication-theoretic concepts, algorithms, and techniques
to important problems in OE system analysis and design. ©
2000 Optical Society of America.},
Doi = {10.1364/AO.39.001679},
Key = {03317572765}
}
@article{03317572783,
Author = {Guo, J and Brady, D},
Title = {Fabrication of thin-film micropolarizer arrays for visible
imaging polarimetry},
Journal = {Applied Optics},
Volume = {39},
Number = {10},
Pages = {1486-1492},
Publisher = {The Optical Society},
Year = {2000},
Month = {April},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/AO.39.001486},
Keywords = {Light polarization;Thin film devices;Optical
films;Multilayers;Image sensors;Optical resolving
power;Polarimeters;CMOS integrated circuits;},
Abstract = {We describe a microfabrication process for fabricating
micropolarizer devices with polarization thin film. The
polarization film is less than a 0.5 µm thick and can have
a polarization extinction ratio of ∼330 in the visible
wavelength range. A single-state micropolarizer array with
polarizing pixels as small as 5 µm × 5 µm has been
fabricated. A multilayer spatially multiplexed three-state
micropolarizer line array with a 14.4-µm resolution has
also been fabricated for visible imaging polarimetry
application. © 2000 Optical Society of America.},
Doi = {10.1364/AO.39.001486},
Key = {03317572783}
}
@article{00095332982,
Author = {Brady, DJ and Rittgers, A and Gallachio, J and Stack, RA and Morrison,
RL},
Title = {Sensing, communications and processing budgets for
tomographic distributed ground sensor arrays},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4040},
Pages = {49-54},
Publisher = {SPIE},
Address = {Orlando, FL, USA},
Year = {2000},
Month = {January},
url = {http://dx.doi.org/10.1117/12.392564},
Keywords = {Image sensors;Computerized tomography;Image
analysis;Infrared imaging;Three dimensional;},
Abstract = {A sensor array is tomographic if sensor modules share raw
information to form a joint target model. Target
identification is then implemented on the global model. This
paper considers sensor head and sensor array resource
budgets for tomographic ground sensors. In this application,
mixed local and global analysis schemes are likely to prove
optimal. We illustrate potential approaches with images and
analysis of 3D visual and infrared targets.},
Doi = {10.1117/12.392564},
Key = {00095332982}
}
@article{00255164833,
Author = {Balberg, M and Hristova, K and Mau, M and Frigon, D and Zeringue, HC and Brady, DJ and Beebe, DJ and Raskin, L},
Title = {Multi-color fluorescence detection of ribosomal RNA in
micro-channels},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {3912},
Pages = {35-40},
Publisher = {SPIE},
Address = {San Jose, CA, USA},
Year = {2000},
Month = {January},
url = {http://dx.doi.org/10.1117/12.379578},
Keywords = {Optical sensors;Fluorescence;RNA;Bacteria;Silicones;Elastomers;Dyes;Color;},
Abstract = {A micro fluidic device capable of detecting the abundance of
bacteria in an environmental solution is described. The
micro channels are made of poly(dimethylsioxane) (PDMS)
elastomer integrated with fused silica capillaries coated
with Aluminum. The detection of specific bacteria is based
on molecular probes (beacons) that emit a fluorescent signal
only when hybridized to the target. This method allows
hybridization in solution, without immobilization, and
avoids washing of the unbound probes. By marking 16S rDNA
oligonucleotide probes (different genetic sequences) with
different color dyes, and detecting the spectral intensity
of light in the micro-channel, different microorganisms can
be detected in one sample. Miniaturization of the analytic
device allows the use of small quantities of RNA molecules,
as target molecules, and improves the detection limits.
Future devices should incorporate a parallel array of
micro-channels, and enable fast and parallel processing of
the molecular signals.},
Doi = {10.1117/12.379578},
Key = {00255164833}
}
@article{6706004,
Author = {Fetterman, MR and Tan, E and Ying, L and Stack, RA and Marks, DL and Feller, S and Cull, E and Sullivan, JM and Munson, DC and Thoroddsen,
ST and Brady, DJ},
Title = {Tomographic imaging of foam},
Journal = {Optics Express},
Volume = {7},
Number = {5},
Pages = {186-197},
Publisher = {The Optical Society},
Year = {2000},
Month = {January},
ISSN = {1094-4087},
url = {http://dx.doi.org/10.1364/OE.7.000186},
Keywords = {bubbles;cameras;CCD image sensors;foams;image
processing;optical tomography;ray tracing;},
Abstract = {The morphology of three-dimensional foams is of interest to
physicists, engineers, and mathematicians. It is desired to
image the 3-dimensional structure of the foam. Many
different techniques have been used to image the foam,
including magnetic resonance imaging, and short-focal length
lenses. We use a camera and apply tomographic algorithms to
accurately image a set of bubbles. We correct for the
distortion of a curved plexiglas container using
ray-tracing. © 2000 Optical Society of America.},
Doi = {10.1364/OE.7.000186},
Key = {6706004}
}
@article{04057951520,
Author = {Tumbar, R and Stack, RA and Brady, DJ},
Title = {Wave-front sensing with a sampling field
sensor},
Journal = {Applied Optics},
Volume = {39},
Number = {1},
Pages = {72-84},
Publisher = {The Optical Society},
Year = {2000},
Month = {January},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/AO.39.000072},
Abstract = {We present a new type of optical wave-front sensor: the
sampling field sensor SFS!. The SFS attempts to solve the
problem of real-time optical phase detection. It has a high
space-bandwidth product and can be made compact and
vibration insensitive. We describe a particular
implementation of this sensor and compare it, through
numerical simulations, with a more mature technique based on
the Shack-Hartmann wave-front sensor. We also present
experimental results for SFS phase estimation. Finally, we
discuss the advantages and drawbacks of this SFS
implementation and suggest alternative implementations. ©
2000 Optical Society of America.},
Doi = {10.1364/AO.39.000072},
Key = {04057951520}
}
@article{00075247489,
Author = {Balberg, M and Barbastathis, G and Fantini, S and Brady,
DJ},
Title = {Confocal imaging through scattering media with a volume
holographic filter},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {3919},
Pages = {69-74},
Publisher = {SPIE},
Address = {San Jose, CA, USA},
Year = {2000},
Month = {January},
url = {http://dx.doi.org/10.1117/12.384180},
Keywords = {Optical microscopy;Holography;Light scattering;Optical
filters;Turbidity;},
Abstract = {The use of a volume holographic filter as collector element
in a confocal system imaging through scattering (turbid)
material is described. We show that the penetration depth of
the volume holographic system is de-coupled from the scatter
noise discrimination properties, and is potentially more
advantageous than the traditional confocal microscope. Since
the volume-holographic filter is a matched-filter, the
penetration depth is dependent on the mismatch of the
refractive index of the sample being imaged relative to the
recording conditions. We present a method to overcome this
limitation based on using a pre-compensating index matching
film during the recording of the volume hologram. An
improvement of the penetration depth is shown
experimentally.},
Doi = {10.1117/12.384180},
Key = {00075247489}
}
@article{00045147460,
Author = {Marks, D and Fetterman, M and Stack, R and Brady,
DJ},
Title = {Spectral tomography from spatial coherence
measurements},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {3920},
Pages = {48-55},
Publisher = {SPIE},
Address = {San Jose, CA, USA},
Year = {2000},
Month = {January},
url = {http://dx.doi.org/10.1117/12.379598},
Keywords = {Coherent light;Spatial variables measurement;Interferometry;Cameras;Fourier
transforms;Interferometers;Algorithms;Microscopic
examination;},
Abstract = {We describe the use of non-focal interferometric cameras for
reconstruction of the four-dimensional power spectral
density of incoherent sources. We develop a 4D version of
the generalized van Cittert-Zernike theorem to establish the
Fourier transform relationship between the mutual coherence
function and the power spectral density. We present
experimental demonstrations of 4D imaging using a rotational
shearing interferometer. We discuss limitations of
interferometric imaging systems and consider how sensor
systems might evolve to combine the stability of focal
systems with the algorithmic sophistication and
multidimensional capacity of interferometry.},
Doi = {10.1117/12.379598},
Key = {00045147460}
}
@article{00115416956,
Author = {West, YD and Schweizer, T and Brady, DJ and Hewak,
DW},
Title = {Gallium lanthanum sulphide fibers for infrared
transmission},
Journal = {Fiber and Integrated Optics},
Volume = {19},
Number = {3},
Pages = {229-250},
Publisher = {Informa UK Limited},
Year = {2000},
url = {http://dx.doi.org/10.1080/01468030050058802},
Keywords = {Semiconducting gallium compounds;Infrared
transmission;Quenching;Fiber lasers;Optical fiber
fabrication;},
Abstract = {Gallium lanthanum sulphide (GLS) glass and fiber have
potential for use in both active and passive infrared
applications. In this paper the optical, thermal, and other
key properties, which are essential for understanding the
applications and crucial in the quest for practical fibres,
are discussed. Glass preparation by melt-quenching and
subsequent fibre fabrication is described using both
rod-in-tube and extruded preforms. Absorptive and scattering
losses are explored as they could represent a fundamental
limitation to successful device fabrication. Potential
passive and active applications are reported and the
prospects for a future generation of sulphide fiber-based
devices examined.},
Doi = {10.1080/01468030050058802},
Key = {00115416956}
}
@article{7000797,
Author = {Balberg, M and Barbastathis, G and Brady, DJ},
Title = {Imaging through turbulence with the volume-holographic
confocal microscope},
Journal = {Proc. Spie Int. Soc. Opt. Eng. (Usa)},
Volume = {4087},
Pages = {1089-1090},
Publisher = {SPIE},
Address = {Quebec City, Que., Canada},
Year = {2000},
url = {http://dx.doi.org/10.1117/12.406352},
Keywords = {holography;light diffraction;optical microscopy;turbulence;},
Abstract = {The confocal microscope with volume-holographic collector
utilizes Bragg selectivity in order to achieve depth
sectioning. The volume hologram is recorded by the
interference of two beams, one of which originates as a
point source at a reference depth. When a reconstructing
(probe) source is at the reference depth, it is
Bragg-matched and causes a strong diffracted signal; sources
at different depths are rejected because of Bragg mismatch.
Therefore, the use of a pinhole in front of the detector (as
in traditional confocal microscopes) is not required. The
arguments for use of a volume hologram instead of a pinhole
to achieve depth sectioning are: (1) the depth resolution of
the microscope is independent of its photon-collection
performance; (2) the hologram phase conjugates aberrations
and other systematic phase distortions, and hence acts as an
ideal matched filter to the reference source (unlike the ad
hoc filtering function performed by the pinhole). We focus
on the depth-resolving properties of volume diffraction when
a turbulent (scattering) medium, emulating a biological
tissue, is present in the path of the light entering the
microscope. In particular, we compare the depth resolution
of a microscope recorded with and without precompensation
for the presence of the scatterer. Precompensation extends
the matched filtering principle by use of a priori
information (the thickness of the turbulent medium) during
the recording phase of the hologram. Our experimental
results demonstrate that precompensation increases the
scatterer thickness over which confocal imaging is
possible},
Doi = {10.1117/12.406352},
Key = {7000797}
}
@article{99035079596,
Author = {Johnson, AJ and Marks, DL and Stack, RA and Brady, DJ and Munson,
DC},
Title = {Three-dimensional surface reconstruction of optical
Lambertian objects using cone-beam tomography},
Journal = {Ieee International Conference on Image Processing},
Volume = {2},
Pages = {663-667},
Address = {Kobe, Jpn},
Year = {1999},
Month = {December},
url = {http://dx.doi.org/10.1109/ICIP.1999.822978},
Keywords = {Tomography;Light reflection;Imaging techniques;Image
quality;Algorithms;},
Abstract = {We develop an approach to the determination of 3-D structure
and reflectivity of Lambertian objects using a modification
of cone-beam tomography. Like other tomographic imaging
methods, our approach is entirely numerical and does not
rely on heuristics. Furthermore, it requires only ambient
illumination.},
Key = {99035079596}
}
@article{00014967590,
Author = {Balberg, M and Barbastathis, G and Brady, DJ and Choi, BK and Liu,
C},
Title = {Holographic 3D imaging of microstructures},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {3801},
Pages = {202-207},
Publisher = {SPIE},
Address = {Denver, CO, USA},
Year = {1999},
Month = {December},
url = {http://dx.doi.org/10.1117/12.363933},
Keywords = {Imaging systems;Three dimensional;Holograms;Scanning
electron microscopy;Microscopes;Silicon wafers;},
Abstract = {A volume holographic matched filter is used for
three-dimensional imaging of silicon microstructures. The
filter is designed by recording a hologram that is matched
to the object depth, allowing confocal imaging of the
structure. Confocal imaging of micro devices provides the
capability to image the performance of the device, which is
not possible in scanning-electron-microscopes (SEM). A
matched holographic filter can also provide more information
about the device than regular confocal imaging. We present a
scanned image of a silicon wafer with micro-fabricated
trenches.},
Doi = {10.1117/12.363933},
Key = {00014967590}
}
@article{00035085021,
Author = {Zou, J and Balberg, M and Byrne, C and Liu, C and Brady,
DJ},
Title = {Optical properties of surface micromachined mirrors with
etch holes},
Journal = {Journal of Microelectromechanical Systems},
Volume = {8},
Number = {4},
Pages = {506-513},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1999},
Month = {December},
url = {http://dx.doi.org/10.1109/84.809066},
Keywords = {Micromachining;Silicon;Polycrystalline materials;Light
reflection;Electromagnetic wave diffraction;Etching;},
Abstract = {We have investigated the optical properties of
surface-micromachined polycrystalline silicon reflectors
within the visible spectral range at five different
wavelengths. The measurement results of the reflectivity of
various microreflectors at four different incident angles
(20°, 30°, 45°, and 60°) are presented. Optical
properties of microreflectors realized using the multiuser
MEMS process (MUMPS) have been investigated. Our studies
have found that etch holes, widely used in the surface
micromachining process to reduce the time for releasing
structures by sacrificial undercutting, have a great
influence on the optical properties of micromachined
mirrors. Diffraction patterns created by two-dimensional
etch-hole arrays on micromachined mirrors have been
investigated. The diffraction by etch holes obeys the
Fraunhofer diffraction theory when a collimated light source
(e.g., a laser beam) is incident. We have shown that when
the dimension of etch holes increases, an increasing portion
of the incident power will be diffracted and transmitted due
to etch holes, leading to decreasing reflectivity of surface
micromachined mirrors.},
Doi = {10.1109/84.809066},
Key = {00035085021}
}
@article{99094796382,
Author = {Marks, DL and Stack, RA and Brady, DJ and Munson, DC and Brady,
RB},
Title = {Visible cone-beam tomography with a lensless interferometric
camera},
Journal = {Science (New York, N.Y.)},
Volume = {284},
Number = {5423},
Pages = {2164-2166},
Publisher = {American Association for the Advancement of Science
(AAAS)},
Year = {1999},
Month = {June},
ISSN = {0036-8075},
url = {http://dx.doi.org/10.1126/science.284.5423.2164},
Keywords = {Cameras;Interferometry;Three dimensional computer
graphics;Coherent light;Image reconstruction;Image
analysis;Functions;},
Abstract = {Digital processing of optical coherence functions can
reconstruct three- dimensional objects illuminated by
incoherent light. It is shown that Fourier analysis of the
mutual intensity of the field produces projections that are
mathematically identical to the projections of x-ray
cone-beam tomography. A lensless interferometric camera that
captures planes of mutual intensity data is described and
used to reconstruct an incoherently illuminated visible
object in three dimensions.},
Doi = {10.1126/science.284.5423.2164},
Key = {99094796382}
}
@article{99104849773,
Author = {Barbastathis, G and Balberg, M and Brady, DJ},
Title = {Confocal microscopy with a volume holographic
filter},
Journal = {Optics Letters},
Volume = {24},
Number = {12},
Pages = {811-813},
Publisher = {The Optical Society},
Year = {1999},
Month = {June},
url = {http://dx.doi.org/10.1364/OL.24.000811},
Keywords = {Holograms;Optical filters;Optical instrument
lenses;Electromagnetic wave diffraction;Optical resolving
power;Alignment;Aberrations;},
Abstract = {A confocal scanning microscopy in which a matched volume
holographic filter replaces the pinhole is described.
Hologram recording is such that the field generated by an
in-focus object is maximally diffracted, whereas
out-of-focus objects are filtered out due to Bragg mismatch.
This decouples dynamic range and axial resolution. The
dynamic range is determined by the diffraction efficiency of
the hologram, and the axial resolution by the numerical
aperture of the objective lens and the hologram thickness.
Additional benefits include ease of alignment and improved
aberration performance.},
Doi = {10.1364/OL.24.000811},
Key = {99104849773}
}
@article{99054674480,
Author = {Purchase, KG and Brady, DJ and Roh, SD and Lammert, RM and Osowski, ML and Coleman, JJ and Hughes, JS},
Title = {Distributed Bragg pulse shaper: Demonstration and
model},
Journal = {Journal of Lightwave Technology},
Volume = {17},
Number = {4},
Pages = {621-628},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1999},
Month = {April},
url = {http://dx.doi.org/10.1109/50.754792},
Keywords = {Pulse shaping circuits;Mirrors;Optical waveguides;Data
communication equipment;Packet networks;Semiconducting
aluminum compounds;Semiconducting gallium arsenide;Solid
state lasers;Ultrafast phenomena;Integrated
optics;Mathematical models;},
Abstract = {The distributed Bragg pulse-shaper (DBPS) is a series of
electrically switchable Bragg mirrors on a semiconductor
waveguide. The DBPS encodes data packets using parallel
electrical signals to set the states of the Bragg mirrors. A
broad-band source pulse then probes the device to generate a
high bandwidth serial wavepacket from the train of partially
reflecting mirrors. This paper describes a DBPS constructed
in AlGaAs. Using this device and a mode-locked Ti:sapphire
laser, we create a 4-bit packet with 0.37 Tb/s burst bit
rate and we demonstrate for the first time that bits in the
wavepacket can be switched by electrical modulation of
individual Bragg segments. We also describe a model
collaborating the observed data.},
Doi = {10.1109/50.754792},
Key = {99054674480}
}
@article{99044647297,
Author = {Marks, DL and Stack, RA and Brady, DJ and Van Der Gracht,
J},
Title = {Three-dimensional tomography using a cubic-phase plate
extended depth-of-field system},
Journal = {Optics Letters},
Volume = {24},
Number = {4},
Pages = {253-255},
Publisher = {The Optical Society},
Year = {1999},
Month = {February},
ISSN = {0146-9592},
url = {http://dx.doi.org/10.1364/OL.24.000253},
Abstract = {We use cubic-phase plate imaging to demonstrate an
order-of-magnitude improvement in the transverse resolution
of three-dimensional objects reconstructed by extended
depth-of-field tomography. Our algorithm compensates for the
range shear of the cubic-phase approach and uses camera
rotation to center the reconstructed volume on a target
object point. © 1999 Optical Society of
America.},
Doi = {10.1364/OL.24.000253},
Key = {99044647297}
}
@article{fds280301,
Author = {Brady, DJ and Jimenez, JL},
Title = {Quantum dot spectrometer},
Journal = {Leos Summer Topical Meeting},
Pages = {3-4},
Year = {1999},
Month = {January},
Abstract = {An account is given on the simulations and experiments on an
electrically-tunable spectrally-sensitive photodetector
based on inhomogeneous absorption in a self-assembled
quantum dot array and resonant tunneling through a coupled
quantum well layer. The preliminary device used in this
study has been constructed based on several concepts using
the InAs-GaAs-AlAs material system. The characteristically
broad inhomogeneous dot luminescence is apparent in the
device.},
Key = {fds280301}
}
@article{99104817475,
Author = {Brady, DJ and Marks, DL and Johnson, AJ and Stack, RA and Munson,
DC},
Title = {Unattended interferometric sensors},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {3713},
Pages = {112-119},
Publisher = {SPIE},
Address = {Orlando, FL, USA},
Year = {1999},
Month = {January},
url = {http://dx.doi.org/10.1117/12.357126},
Keywords = {Interferometry;Infrared imaging;Coherent light;Sensor data
fusion;Image reconstruction;},
Abstract = {We describe tomographic integration of visible and IR
projections to form 3D models of object spaces. 3D modeling
is a computationally efficient means of multiple sensor data
reduction and a robust means of scene analysis. We consider
how imaging system design might be revised to obtain 3D data
and present experimental data from a compact interferometric
coherence imaging system. We experimentally and
theoretically analyze 3D reconstructions of macroscopic
objects, focusing in particular on the reconstruction of an
automobile using a conventional camera.},
Doi = {10.1117/12.357126},
Key = {99104817475}
}
@article{04057907674,
Author = {Marks, DL and Stack, RA and Brady, DJ},
Title = {Three-dimensional coherence imaging in the fresnel
domain},
Journal = {Applied Optics},
Volume = {38},
Number = {8},
Pages = {1332-1342},
Publisher = {The Optical Society},
Year = {1999},
Month = {January},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/AO.38.001332},
Abstract = {We show that three-dimensional incoherent primary sources
can be reconstructed from finite-aperture Fresnel-zone
mutual intensity measurements by means of coordinate and
Fourier transformation. The spatial bandpass and impulse
response for three-dimensional imaging that result from use
of this approach are derived. The transverse and
longitudinal resolutions are evaluated as functions of
aperture size and source distance. The longitudinal
resolution of three-dimensional coherence imaging falls
inversely with the square of the source distance in both the
Fresnel and Fraunhofer zones. We experimentally measure the
three-dimensional point-spread function by using a
rotational shear interferometer. © 1999 Optical Society of
America.},
Doi = {10.1364/AO.38.001332},
Key = {04057907674}
}
@article{99104830932,
Author = {Barbastathis, G and Brady, DJ},
Title = {Spatio-spectral tomography of luminescent objects with
volume holograms},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {3749},
Pages = {398-399},
Publisher = {SPIE},
Address = {San Francisco, CA, USA},
Year = {1999},
Month = {January},
url = {http://dx.doi.org/10.1117/12.354804},
Keywords = {Tomography;Holograms;Image reconstruction;Optical resolving
power;Color;},
Abstract = {Volume holograms as optical imaging elements provide maximum
flexibility in the design of the optical response. For
example, when a polychromatic incoherent object illuminates
a spherical-reference volume hologram, the shift selectivity
effect extracts only a color-dependent slice of the object,
which is reconstructed on a planar detector. In this
presentation we characterize the performance (resolution and
dynamic range) of a tomographic imaging system based on this
effect.},
Doi = {10.1117/12.354804},
Key = {99104830932}
}
@article{99094789724,
Author = {Barbastathis, G and Brady, DJ},
Title = {Volume holographic imaging of three-dimensional
objects},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {3633},
Pages = {170-181},
Publisher = {SPIE},
Address = {San Jose, CA, USA},
Year = {1999},
Month = {January},
url = {http://dx.doi.org/10.1117/12.349324},
Keywords = {Holograms;Three dimensional;Image reconstruction;Tomography;},
Abstract = {Spherical-reference volume holograms exhibit spatial
selectivity to the location and color of the reconstructing
beam. We show that this property enables tomographic
operations on extended incoherent polychromatic objects, and
derive the shapes and spectral contents of the reconstructed
slices for several holographic arrangements.},
Doi = {10.1117/12.349324},
Key = {99094789724}
}
@article{00025011777,
Author = {Barbastathis, G and Brady, DJ},
Title = {Multidimensional Tomographie Imaging Using Volume
Holography},
Journal = {Proceedings of the Ieee},
Volume = {87},
Number = {12},
Pages = {2098-2120},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1999},
Month = {January},
ISSN = {0018-9219},
url = {http://dx.doi.org/10.1109/5.805924},
Keywords = {Holography;Three dimensional computer graphics;},
Abstract = {We propose the application of volume holography to
fourdimensional (4-D) spatiospectral imaging. The proposed
systems use materials and techniques developed for
holographic data storage and interconnections to capture
three-dimensional (3-D) spatial and one-dimensional (1-D)
spectral information about a remote light source or
scatterer. We analyze case studies of simple architectures
using spherical-reference volume holograms as imaging
elements in a fluorescence confocal microscope arrangement
and demonstrate the equivalence of the holographic
degeneracies with a slicing operation on the reconstructing
incoherent source. We develop a general theoretical
framework for the diffraction of random fields from volume
holograms and show that the formulation can be used as an
imaging design tool. Applications and future directions are
also discussed. © 1999 IEEE.},
Doi = {10.1109/5.805924},
Key = {00025011777}
}
@article{6512580,
Author = {Brady, D.J. and Jimenez, J.L.},
Title = {The quantum dot spectrometer},
Journal = {1999 Digest of the LEOS Summer Topical Meetings:
Nanostructures and Quantum Dots/WDM Components/VCSELs and
Microcavaties/RF Photonics for CATV and HFC Systems (Cat.
No.99TH8455)},
Pages = {3 - 4},
Address = {San Diego, CA, USA},
Year = {1999},
url = {http://dx.doi.org/10.1109/LEOSST.1999.794631},
Keywords = {aluminium compounds;gallium arsenide;III-V
semiconductors;indium compounds;infrared
spectrometers;optical arrays;photodetectors;quantum well
devices;resonant tunnelling devices;self-assembly;semiconductor
heterojunctions;semiconductor quantum dots;},
Abstract = {We describe the simulations and experiments on an
electrically-tunable spectrally-sensitive photodetector
based on inhomogeneous absorption in a self-assembled
quantum dot array and resonant tunneling through a coupled
quantum well layer. The basic structure of our device, the
quantum dot spectrometer (QDS) is given. The key components
are the quantum dot layer, which produces spectrally
sensitive absorption and the coupling layer, which reads out
spectral information as a function of the applied voltage,
V. The coupling layer consists of a pair of coupled quantum
wells. For certain applied bias voltages across the quantum
wells, resonant transfer from the quantum dot layer to the
collector layer occurs. We have constructed a preliminary
device based on these concepts using the InAs-GaAs-AlAs
material system},
Key = {6512580}
}
@article{00025026124,
Author = {Brady, DJ and Fagan, N and Harwood, DWJ and Hesford, MJ and Hewak, DW and Hudson, TB and Moore, RC and Payne, DN and Schweizer, T and Taylor, ERM and Tucknott, JA and Voyce, CJ and Weatherby, E and West,
YD},
Title = {Optical amplifiers and lasers in infrared
fibres},
Journal = {Proceedings of Spie the International Society for Optical
Engineering},
Volume = {3849},
Pages = {85-92},
Publisher = {SPIE},
Address = {Boston, MA, USA},
Year = {1999},
url = {http://dx.doi.org/10.1117/12.372803},
Keywords = {Optical fibers;Infrared radiation;Gallium compounds;Fiber
lasers;Quenching;Fluorine compounds;},
Abstract = {We are currently investigating two infrared glasses for
active applications. Gallium lanthanum sulphide (GLS) glass
is investigated as a potential host material for rare-earth
doped mid-infrared fibre lasers. We have fabricated gallium
lanthanum sulphide glass by melt quenching and drawn it into
fibres using the rod-in-tube technique. Fluoroaluminate
glasses (ALF) are being prepared in planar form by spin
coating and clad waveguides have been achieved. The quality
of waveguides from both these materials is gradually being
improved as methods to eliminate transition metals and other
impurities, understand crystallization and reduce the
imperfections at the core/clad interface are developed.
Although initially motivated by the demand for a practical
1310 nm amplifier, interest has now extended further into
the infrared. We describe recent progress in these glasses,
their properties and applications.},
Doi = {10.1117/12.372803},
Key = {00025026124}
}
@article{fds280299,
Author = {Zhang, X and Brady, D},
Title = {Asymptotic multiuser efficiencies for decision-directed
multiuser detectors},
Journal = {Ieee Transactions on Information Theory},
Volume = {44},
Number = {2},
Pages = {502-515},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1998},
Month = {December},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.661500},
Abstract = {The asymptotic multiuser efficiencies (AME's) are derived
for various classes of decision-directed multiuser
detectors, including multistage detectors, and
decision-feedback detectors. Novel classes of soft-decision
multistage detectors are proposed and analyzed in this
paper. Each class is specified in part by a soft-decision
nonlinearity, such as a symmetric quantizer or a linear
clipper. Closed-form expressions for two-user AME's are
derived for soft-decision two-stage detectors and can be
used as a design criterion to optimize the soft-decision
nonlinearities. For a special case of two synchronous users,
the soft-decision two-stage detector using an optimized
linear clipper with either conventional or decorrelated
tentative decisions is shown to achieve optimum AME. Upper
and lower bounds on the AME are obtained for
decision-feedback detectors using either conventional or
decorrelated tentative decisions. It is demonstrated that
decision-directed multiuser detectors with conventional
tentative decisions have low near-far resistance compared to
those with decorrelated tentative decisions. © 1998
IEEE.},
Doi = {10.1109/18.661500},
Key = {fds280299}
}
@article{99024581923,
Author = {Brady, DJ and Marks, DL and Stack, R},
Title = {Fresnel zone interferometric imaging},
Journal = {Conference Proceedings Lasers and Electro Optics Society
Annual Meeting Leos},
Volume = {2},
Pages = {205-206},
Address = {Orlando, FL, USA},
Year = {1998},
Month = {December},
url = {http://dx.doi.org/10.1109/LEOS.1998.739532},
Keywords = {Interferometers;Fast Fourier transforms;Mathematical
models;Light emitting diodes;Integral equations;},
Abstract = {Fourier analysis in projective coordinates shows similar
inversion in the Fresnel zone. Since the longitudinal
resolution of 3D coherence imaging falls inversely in the
square of range in both the Fresnel and Fraunhofer zones,
extension to the Fresnel zone dramatically improves
longitudinal resolution by removing far-field range
constraints. The utility of this method is demonstrated
using rotational shear interferometers (RSI), which measure
complete planes of coherence measures in a single frame.
These experiments demonstrate that the incoherent field in
an aperture may contain substantially more object
information than conventional imaging systems
detect.},
Key = {99024581923}
}
@article{03217478728,
Author = {Zou, J and Byrne, C and Liu, C and Brady, D},
Title = {Optical properties of micromachined polysilicon reflective
surfaces with etching holes},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {3511},
Pages = {307-314},
Publisher = {SPIE},
Address = {Santa Clara, CA, United States},
Year = {1998},
Month = {December},
url = {http://dx.doi.org/10.1117/12.324315},
Keywords = {Micromachining;Polysilicon;Reflection;Surface
roughness;Etching;Integrated circuits;Laser
beams;Diffraction;Optimization;Optical systems;Microoptics;},
Abstract = {MUMPS (Multi-User MEMS Process) is receiving increasingly
wide use in micro optics. We have investigated the optical
properties of the polysilicon reflective surface in a
typical MUMPS chip within the visible light spectrum. The
effect of etching holes on the reflected laser beam is
studied. The reflectivity and diffraction patterns at five
different wavelengths have been measured. The optical
properties of the polysilicon reflective surface are greatly
affected by the surface roughness, the etching holes, as
well as the material. The etching holes contribute to
diffraction and reduction of reflectivity. This study
provides a basis for optimal design of micromachined
free-space optical systems.},
Doi = {10.1117/12.324315},
Key = {03217478728}
}
@article{98074282851,
Author = {Marks, DL and Brady, DJ},
Title = {Three-dimensional source reconstruction with a scanned
pinhole camera},
Journal = {Optics Letters},
Volume = {23},
Number = {11},
Pages = {820-822},
Publisher = {The Optical Society},
Year = {1998},
Month = {June},
url = {http://dx.doi.org/10.1364/OL.23.000820},
Abstract = {We present a simple reconstruction algorithm for
three-dimensional (3D) incoherent source distributions
imaged by a laterally scanned pinhole camera. We consider
digital sampling of multiple pinhole images for 3D
reconstruction and implement an experimental demonstration
with lateral resolution of 2 × 10-3 rad and longitudinal
resolution of approximately 0.14z2 m, where z is the
object-to-pinhole distance in meters. © 1998 Optical
Society of America.},
Doi = {10.1364/OL.23.000820},
Key = {98074282851}
}
@article{98024043991,
Author = {Jimenez, JL and Fonseca, LRC and Brady, DJ and Leburton, JP and Wohlert,
DE and Cheng, KY},
Title = {The quantum dot spectrometer},
Journal = {Applied Physics Letters},
Volume = {71},
Number = {24},
Pages = {3558-3560},
Publisher = {AIP Publishing},
Year = {1997},
Month = {December},
url = {http://dx.doi.org/10.1063/1.120390},
Keywords = {Photodetectors;Semiconductor quantum dots;Semiconductor
device structures;Design;Semiconductor materials;Computer
simulation;Finite difference method;Electron
scattering;},
Abstract = {We propose a novel photodetector capable of multi-spectral
channel operation. The device makes use of the ability of a
quantum dot plane to capture an optical spectrum, and of a
resonant-tunneling structure to perform spectrally sensitive
read-out. We present a design made out in the
InAs-GaAs-AlxGa1 - xAs system. We also present realistic
simulations of the optical channel capabilities, as well as
a discussion of the possible problems of the device. © 1997
American Institute of Physics.},
Doi = {10.1063/1.120390},
Key = {98024043991}
}
@article{fds280298,
Author = {Gray, SD and Preisig, JC and Brady, D},
Title = {Multiuser detection in a horizontal underwater acoustic
channel using array observations},
Journal = {Ieee Transactions on Signal Processing},
Volume = {45},
Number = {1},
Pages = {148-160},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1997},
Month = {December},
ISSN = {1053-587X},
url = {http://dx.doi.org/10.1109/78.552213},
Abstract = {We present a multisensor, multiuser receiver that is capable
of operating in an underwater acoustic channel with severe
niultipath. For each active user, the receiver consists of a
multi-input, single-output array processing filter followed
by a single-channel adaptive equalizer. The array processing
filter is chosen to maximize an averaged performance metric
which measures reduction in the interference from multiple
asynchronous cochannel users and the reduction in
intersymbol interference caused by time spreading of the
transmitted signal. The singlechannel adaptive equalizer
that follows the array processing filter eliminates the
remaining intersymbol interference prior to hard symbol
decisions. The division of labor between the array
processing filter and single-channel equalizer reduces
receiver complexity by allowing the array processing filter
weights to be based on the fixed deterministic channel
component and the single-channel equalizer to be based on
the stochastic channel component. Receiver performance is
demonstrated using data obtained from two shallow-water
acoustic channels where two cochannel users are transmitting
in shallow water at 18 and 30 nautical miles from the
receiver array. © 1997 IEEE.},
Doi = {10.1109/78.552213},
Key = {fds280298}
}
@article{97093841064,
Author = {Ramachandran, S and Pepper, JC and Brady, DJ and Bishop,
SG},
Title = {Micro-optical lenslets by photo-expansion in chalcogenide
glasses},
Journal = {Journal of Lightwave Technology},
Volume = {15},
Number = {8},
Pages = {1371-1377},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1997},
Month = {August},
ISSN = {0733-8724},
url = {http://dx.doi.org/10.1109/50.618346},
Keywords = {Photosensitivity;Optical collimators;Light
absorption;Optical instrument lenses;Photons;Photochromism;Crystal
atomic structure;Atomic force microscopy;Dye
lasers;},
Abstract = {A detailed study of the wavelength dependence of the
formation of lenslets by photo-expansion in chalcogenide
glasses is reported. Photo-expansion in chalcogenide glasses
offers a one-step fabrication process to record surface
structures such as gratings and microlenses. The process is
purely optical and requires no fixing and etching to get the
desired surface structure. Two competing effects, namely
large volumes accessed by low energy photons and large
magnitudes of photostructural changes due to high energy
photons, provide the possibility of using different
fabrication techniques to obtain lenslets by the
photoexpansion process. Strongly absorbed 514.5 nm light is
used to record micro-optical lenslets in As 2S 3 glass and
up to 10% relative volume changes are observed. The low
power density requirements at this wavelength are used to
demonstrate a parallel lithographic fabrication technique
for recording lenslets with high repeatability and
throughput, and with excellent control over curvature and
dimensions. The magnitude of surface dilation is maximized
at the photon energy that combines the advantage of short
wavelength exposures in producing large percentage volume
changes, with the advantage of low energy photons in
irradiating large volumes of the glass matrix. A variety of
wavelengths within the Urbach tail range of the optical
absorption edge are employed to find the optimal wavelength
for large absolute volume changes in As 2S 3 glass. Lenslets
as high as 8 μm are fabricated with focused light exposures
from a dye laser operating at 584.5 nm. Lenslets are
structurally characterized with alpha-step scanners and an
atomic force microscope (AFM) and are optically
characterized by testing the collimation of 1550-nm light
emerging from a single-mode fiber with these
lenslets.},
Doi = {10.1109/50.618346},
Key = {97093841064}
}
@article{97073727428,
Author = {Hill, KB and Basinger, SA and Stack, RA and Brady,
DJ},
Title = {Noise and information in interferometric cross
correlators},
Journal = {Applied Optics},
Volume = {36},
Number = {17},
Pages = {3948-3958},
Publisher = {The Optical Society},
Year = {1997},
Month = {June},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/AO.36.003948},
Abstract = {We consider optical interferometric cross correlators based
on broadband light sources. We derive the signal-to-noise
ratio from basic principles and supply experimental evidence
that corroborates the theoretical analysis. Noise sources
are discussed, and the signal-to-noise ratio of our
experimental system is measured. © 1997 Optical Society of
America.},
Doi = {10.1364/AO.36.003948},
Key = {97073727428}
}
@article{97043597442,
Author = {Basinger, SA and Brady, DJ and Michielssen, E},
Title = {Superresolution through space-time control of two-level
quantum systems},
Journal = {Journal of the Optical Society of America
B},
Volume = {14},
Number = {3},
Pages = {503-510},
Publisher = {The Optical Society},
Year = {1997},
Month = {January},
ISSN = {0740-3224},
url = {http://dx.doi.org/10.1364/JOSAB.14.000503},
Abstract = {Spatial structure created by pulsed field interactions with
two-level systems is considered. Superresolved pattern
formation is possible by the use of extra degrees of freedom
programmed in the time-domain field. In analogy with slice
selection in magnetic resonance imaging, the two-level
system with no decay constants is shown to be completely
controllable. The effects of noise, dephasing, and
inhomogeneous broadening are considered. © 1997 Optical
Society of America.},
Doi = {10.1364/JOSAB.14.000503},
Key = {97043597442}
}
@article{5676443,
Author = {Guo, J and Brady, DJ},
Title = {Fabrication of high-resolution micropolarizer
arrays},
Journal = {Optical Engineering},
Volume = {36},
Number = {8},
Pages = {2268-2271},
Publisher = {SPIE-Intl Soc Optical Eng},
Year = {1997},
Month = {January},
ISSN = {0091-3286},
url = {http://dx.doi.org/10.1117/1.601452},
Keywords = {optical fabrication;optical films;optical filters;optical
polarisers;optical polymers;optical resolving
power;},
Abstract = {Procedures for creating high-resolution polarization filter
arrays using multilayer polyvinyl alcohol (PVA) films are
described. Two state polarization filter arrays with 25 μm
resolution and three state polarization filter arrays with
48 μm resolution are demonstrated. © 1997 Society of
Photo-Optical Instrumentation Engineers.},
Doi = {10.1117/1.601452},
Key = {5676443}
}
@article{98014027088,
Author = {Basinger, SA and Stack, RA and Hill, KB and Brady,
DJ},
Title = {Superresolved optical scanning using polychromatic
light},
Journal = {Journal of the Optical Society of America
A},
Volume = {14},
Number = {12},
Pages = {3242-3250},
Publisher = {The Optical Society},
Year = {1997},
Month = {January},
ISSN = {0740-3232},
url = {http://dx.doi.org/10.1364/JOSAA.14.003242},
Keywords = {Interferometry;Light;Data acquisition;Data
reduction;Mathematical models;Feature extraction;Data
structures;Three dimensional;Computer simulation;Position
measurement;},
Abstract = {Subwavelength detection of object displacement with use of a
polychromatic interferometric imaging system is demonstrated
experimentally. Object position detection with 50-nm lateral
resolution is achieved. This result derives from and is
consistent with increases in information capacity with use
of phase-sensitive polychromatic systems identified by
Basinger et al. [J. Opt. Soc. Am. A 12, 704 (1995)]. This
phase-sensitive polychromatic detection relies on an imaging
interferometric cross-correlating receiver capable of 2-nm
optical path difference resolution. © 1997 Optical Society
of America.},
Doi = {10.1364/JOSAA.14.003242},
Key = {98014027088}
}
@article{97053641892,
Author = {Zvonar, Z and Brady, D and Catipovic, J},
Title = {Adaptive decentralized multiuser receiver for deep-water
acoustic telemetry},
Journal = {Journal of the Acoustical Society of America},
Volume = {101},
Number = {4},
Pages = {2384},
Publisher = {Acoustical Society of America (ASA)},
Year = {1997},
url = {http://dx.doi.org/10.1121/1.418252},
Abstract = {An acoustic local area network has been deployed for
multipoint-to- point telemetry between ocean bottom sensors
and a surface receiver in deep- water areas. A major
obstacle for coherent communications in this channel is
strong multiple-access interference from other acoustic
modems, which affects a common narrowband request channel of
the network protocol. The network throughput and packet
delay depend on the capability of the receiver to resolve
collisions between request packets. In this paper a
multiuser receiver for joint channel parameter estimation,
multiple-access interference suppression and signal
detection is proposed. The receiver is fully adaptive,
requiring no side information about the channel conditions
or the signal parameters of the interfering users in the
network. Receiver performance is demonstrated through
experiments in a deep-water acoustic channel.},
Doi = {10.1121/1.418252},
Key = {97053641892}
}
@article{04358327724,
Author = {Schweizer, T and Brady, DJ and Hewak, DW},
Title = {Fabrication and spectroscopy of erbium doped gallium
lanthanum sulphide glass fibres for mid-infrared laser
applications},
Journal = {Optics Express},
Volume = {1},
Number = {4},
Pages = {102-107},
Year = {1997},
Keywords = {Erbium;Semiconductor doping;Infrared spectroscopy;Fiber
lasers;Laser applications;Fluorescence;Luminescence;},
Abstract = {Gallium lanthanum sulphide based glasses are proposed as
high quality hosts for rare-earth doped, mid-infrared fibre
lasers, that would offer compact and rugged sources for gas
sensing, atmospheric transmission, and medical applications.
The infrared emission spectroscopy of erbium doped glasses
and fibres shows the potential of this glass host for the
above applications. Mid-infrared transitions at 2.0, 2.75,
3.6, and 4.5μm have been detected and characterized.
© 1997 Optical Society of America.},
Key = {04358327724}
}
@article{97013496375,
Author = {Ramachandran, S and Brady, DJ and Bishop, SG},
Title = {Parallel lithographic fabrication of micro-optical lenslets
by photoexpansion in chalcogenide glasses},
Journal = {Conference Proceedings Lasers and Electro Optics Society
Annual Meeting Leos},
Volume = {1},
Pages = {284-285},
Address = {Boston, MA, USA},
Year = {1996},
Month = {December},
url = {http://dx.doi.org/10.1109/LEOS.1996.565242},
Keywords = {Optical glass;Laser recording;Light absorption;Photolithography;Integrated
circuit manufacture;Laser beam effects;Gas
lasers;Expansion;},
Abstract = {The non-locality of the photoexpansion effect as well as
large volume changes observed in the fabrication of
micro-lenses on the surface of As2S3 (chalcogenide) glass
was investigated experimentally. The parallel
photolithographic process was used in micro-lens and lens
array fabrication because of its distinct advantages over
focused light techniques. The process allowed excellent
control on feature size. The non-local expansion gave smooth
rounded edges and a sufficiently small exposure resulted in
a convex structure. Smaller lenslets seemed to preserve
their convex structure and showed higher aspect
ratios.},
Key = {97013496375}
}
@article{fds330756,
Author = {Carrilho, E and Ruiz-Martinez, MC and Berka, J and Smirnov, I and Goetzinger, W and Miller, AW and Brady, D and Karger,
BL},
Title = {Rapid DNA sequencing of more than 1000 bases per run by
capillary electrophoresis using replaceable linear
polyacrylamide solutions.},
Journal = {Analytical Chemistry},
Volume = {68},
Number = {19},
Pages = {3305-3313},
Year = {1996},
Month = {October},
url = {http://dx.doi.org/10.1021/ac960411r},
Abstract = {The read length for DNA sequencing using capillary
electrophoresis and replaceable linear polyacrylamide (LPA)
solutions has been extended to more than 1000 bases with a
run time of 80 min. This result was successfully achieved
through the combined use of cycle sequencing with
dye-labeled primers, improved matrix and separation
conditions, and enhanced base-calling software. The
influences of LPA molecular weight and concentration on
separation were investigated. Additionally, the separation
buffer, column temperature, and electric field were adjusted
to increase the number of resolvable DNA fragments per run
while maintaining an enhanced separation speed. Using low
concentrations [2% (w/v)] of high molecular weight LPA
polymers (> 5.5 x 10(6) Da), elevated column temperature (50
degrees C) and moderately high field (150 V/cm), rapid
sequencing analysis for more than 1000 bases on a model
ssM13mp18 template was obtained with 96.8%
accuracy.},
Doi = {10.1021/ac960411r},
Key = {fds330756}
}
@article{96083296422,
Author = {Ramachandran, S and Bishop, SG and Guo, JP and Brady,
DJ},
Title = {Fabrication of holographic gratings in As2S3
glass by photoexpansion and photodarkening},
Journal = {Ieee Photonics Technology Letters},
Volume = {8},
Number = {8},
Pages = {1041-1043},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1996},
Month = {August},
ISSN = {1041-1135},
url = {http://dx.doi.org/10.1109/68.508731},
Keywords = {Optical glass;Arsenic compounds;Photochromism;Mathematical
models;Optical variables measurement;Atomic force
microscopy;Semiconductor device manufacture;Semiconductor
device structures;Laser beams;Interferometers;Helium neon
lasers;},
Abstract = {The spatial dynamics of the photo-induced surface relief and
phase gratings in As2S3 glass are described. Excursion
amplitudes up to 150 nm and grating efficiencies up to 27%
are observed. Depth and resolution limits for the effect are
measured and a model for the resolution limit is
proposed.},
Doi = {10.1109/68.508731},
Key = {96083296422}
}
@article{fds280297,
Author = {Zvonar, Z and Brady, D and Catipovic, J},
Title = {Adaptive detection for shallow-water acoustic telemetry with
cochannel interference},
Journal = {Ieee Journal of Oceanic Engineering},
Volume = {21},
Number = {4},
Pages = {528-536},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1996},
Month = {January},
ISSN = {0364-9059},
url = {http://dx.doi.org/10.1109/48.544062},
Abstract = {Adaptive decision feedback equalization (DFE) has recently
been used to enable high-rate data transmission through
shallow-water acoustic channels. This adaptive receiver
successfully tracks and suppresses intersymbol interference
due to a dispersive multipath channel. However, acoustic
modems which are used for network applications must also
contend with interference due to cochannel signals from
proximal modems. In this work, we propose and evaluate a
multiuser receiver with cochannel interference suppression.
The advantages of this multiuser receiver in the presence of
strong cochannel interference are shown by a performance
comparison to a bank of the single-user DFK's described
above. Conclusions are supported in part by the demodulation
of experimental data for two simultaneous cochannel signals
and by a steady-stale performance analysis.},
Doi = {10.1109/48.544062},
Key = {fds280297}
}
@article{96073231176,
Author = {Brady, DJ and Basinger, SA and Stack, RA and Hill, KB and Guo,
J},
Title = {Characterization of complex space-time optical
fields},
Journal = {Proceedings of Spie the International Society for Optical
Engineering},
Volume = {2701},
Pages = {152-158},
Publisher = {SPIE},
Address = {San Jose, CA, USA},
Year = {1996},
Month = {January},
url = {http://dx.doi.org/10.1117/12.239705},
Keywords = {Ultrafast phenomena;Characterization;Holography;Interferometry;Signal
to noise ratio;Signal detection;},
Abstract = {We consider interferometric techniques for capturing
ultra-fast pulsed images. We analyze the signal-to-noise
performance and information capacity of pulsed image
detection systems and we briefly discuss the possibility of
improving detection systems using spectral holographic image
capture.},
Doi = {10.1117/12.239705},
Key = {96073231176}
}
@article{fds323378,
Author = {Ramachandran, S and Bishop, SG and Brady, DJ},
Title = {Dynamic grating formation in As2S3},
Journal = {Conference Proceedings Lasers and Electro Optics Society
Annual Meeting Leos},
Pages = {259-260},
Year = {1996},
Month = {January},
Abstract = {This work focuses on using the photoexpansion effect to
fabricate surface-grating structures and studying the
applicability in photonic circuitry. Surface gratings with
periods ranging from 2.95 μm to 0.377 μm were written
holographically using 514.5-nm light from an Argon ion
laser. Gratings with 2.95-μm period were also written for
different exposure times to study the dose effect on
surface-relief structures. AFM images of the irradiated
surfaces were obtained. A He-Ne laser operating at 632.8 nm
enabled to measure diffraction efficiencies.},
Key = {fds323378}
}
@article{5464933,
Author = {Ramachandran, S and Bishop, SG and Brady, DJ},
Title = {Dynamic grating formation in As2S3},
Journal = {Conference Proceedings Lasers and Electro Optics Society
Annual Meeting Leos},
Pages = {259-260},
Address = {Anaheim, CA, USA},
Year = {1996},
Keywords = {arsenic compounds;atomic force microscopy;chalcogenide
glasses;holographic gratings;optical fabrication;optical
glass;optical microscopy;},
Abstract = {This work focuses on using the photoexpansion effect to
fabricate surface-grating structures and studying the
applicability in photonic circuitry. Surface gratings with
periods ranging from 2.95 μm to 0.377 μm were written
holographically using 514.5-nm light from an Argon ion
laser. Gratings with 2.95-μm period were also written for
different exposure times to study the dose effect on
surface-relief structures. AFM images of the irradiated
surfaces were obtained. A He-Ne laser operating at 632.8 nm
enabled to measure diffraction efficiencies.},
Key = {5464933}
}
@article{96012995984,
Author = {Purchase, KG and Brady, DJ and Smith, GM and Roh, SD and Osowski, ML and Coleman, JJ},
Title = {Integrated optical pulse shapers for high-bandwidth data
packet encoding},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {2613},
Pages = {43-51},
Address = {Philadelphia, PA, USA},
Year = {1995},
Month = {December},
ISSN = {0277-786X},
Keywords = {Signal encoding;Pulse modulation;Integrated
optics;Design;Fabrication;},
Abstract = {We describe distributed Bragg pulse shapers for the
ultra-fast communication system wavepacket encoding. We
discuss Bragg pulse shaper design and fabrication and we
present experimental results from first and second
generation devices.},
Key = {96012995984}
}
@article{fds340979,
Author = {Greenberg, JA and Lakshmanan, M and Samei, E and Brady, D and Kapadia,
A},
Title = {Experimental implementation of coded aperture coherent
scatter spectral imaging of cancerous and healthy breast
tissue samples},
Journal = {Proc. Spie 9412, Medical Imaging 2015: Physics of Medical
Imaging},
Publisher = {SPIE},
Year = {1995},
Month = {April},
url = {http://dx.doi.org/10.1117/12.208231},
Doi = {10.1117/12.208231},
Key = {fds340979}
}
@article{95042669868,
Author = {Basinger, SA and Michielssen, E and Brady, DJ},
Title = {Degrees of freedom of polychromatic images},
Journal = {Journal of the Optical Society of America
A},
Volume = {12},
Number = {4},
Pages = {704-714},
Publisher = {The Optical Society},
Year = {1995},
Month = {January},
url = {http://dx.doi.org/10.1364/JOSAA.12.000704},
Keywords = {Microscopic examination;Spatial variables
measurement;Mathematical models;Electromagnetic wave
scattering;Detectors;},
Abstract = {Detection and evaluation of time- and space-domain fields
scattered by one-dimensional objects is considered for
applications in superresolved microscopy. Modal
decomposition of scattered fields is used to estimate the
information passed by band-limited diffraction from an
object to the far field. The transinformation is shown to
increase with the number of frequencies in the probe field.
© 1995 Optical Society of America.},
Doi = {10.1364/JOSAA.12.000704},
Key = {95042669868}
}
@article{fds330760,
Author = {Zvonar, Z and Brady, D},
Title = {Suboptimal Multiuser Detector for Frequency-Selective
Rayleigh Fading Synchronous CDMA Channels},
Journal = {Ieee Transactions on Communications},
Volume = {43},
Number = {234},
Pages = {154-157},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1995},
Month = {January},
url = {http://dx.doi.org/10.1109/26.380025},
Abstract = {We propose a suboptimal low-complexity multiuser receiver
for synchronous CDMA frequency-selective Rayleigh fading
channels. In contrast to the conventional RAKE receiver,
which suffers from near-far effects due to channel fading,
the proposed multiuser receiver is shown to alleviate the
near-far problem while preserving multipath diversity gain.
This is demonstrated by comparing the symbol error
probability and asymptotic multiuser efficiency of the
proposed multiuser detector and RAKE receiver. © 1995
IEEE},
Doi = {10.1109/26.380025},
Key = {fds330760}
}
@article{fds330761,
Author = {Zvonar, Z and Brady, D},
Title = {Differentially Coherent Multiuser Detection in Asynchronous
CDMA Flat Rayleigh Fading Channels},
Journal = {Ieee Transactions on Communications},
Volume = {43},
Number = {234},
Pages = {1252-1255},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1995},
Month = {January},
url = {http://dx.doi.org/10.1109/26.380162},
Abstract = {We present the performance analysis of decorrelating
detector for differentially coherent transmission over a
CDMA frequency-nonselective Rayleigh fading channel. While
the correlation-type receiver is near-far limited in this
channel, it is shown that the aforementioned multiuser
detector eliminates the bit error rate floor and alleviates
the near-far problem. © 1995 IEEE},
Doi = {10.1109/26.380162},
Key = {fds330761}
}
@article{fds330763,
Author = {Gray, SD and Kocic, M and Brady, D},
Title = {Multiuser Detection in Mismatched Multiple-Access
Channels},
Journal = {Ieee Transactions on Communications},
Volume = {43},
Number = {12},
Pages = {3080-3089},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1995},
Month = {January},
url = {http://dx.doi.org/10.1109/26.477511},
Abstract = {In this paper we consider an additive white Gaussian noise
multiple-access channel and investigate the performance
degradation of several multiuser detectors due to imperfect
knowledge of channel parameters, induced by either
estimation errors or sampling/quantization of the receiver's
sufficient statistics. The symbol error rates and the
asymptotic multiuser efficiencies (AME's) of these detectors
are examined as functions of both true and approximated
channel parameters for 2 asynchronous users. The results
quantify the loss of near-far resistance due to parameter
estimation errors and demonstrate that detectors which are
optimal for ideal conditions are often more sensitive to
parameter mismatch. Examples are given which illustrate a
reverse ordering of the symbol error rates for these
detectors in the high signal-to-noise regime, and also
illustrate cases when the conventional matched-filter
detector exhibits superior performance over multiuser
detectors. © 1995 IEEE},
Doi = {10.1109/26.477511},
Key = {fds330763}
}
@article{95062736916,
Author = {Hill Kent and B and Purchase Kenneth and G and Brady David,
J},
Title = {Pulsed-image generation and detection},
Journal = {Optics Letters},
Volume = {20},
Number = {10},
Pages = {1201-1203},
Publisher = {The Optical Society},
Year = {1995},
url = {http://dx.doi.org/10.1364/OL.20.001201},
Keywords = {Holograms;Lithium compounds;Three dimensional;Image
compression;Interferometry;Laser pulses;Mathematical
models;Integral equations;Fast Fourier transforms;},
Abstract = {A volume holographic pulse shaper that programs the
three-dimensional space-time structure of optical fields is
described. This system produces images in which each pixel
contains an independent and programmable pulse shape. The
pulsed images were recorded using a z-cut 1 cm × 1 cm
× 1 cm 0.1% iron-doped lithium niobate crystal from
Deltronic. The construction of an interferometric cross
correlator was key to the detection of the shaped field.
Programmable pulsed images are of particular interest to
quantum dynamical control.},
Doi = {10.1364/OL.20.001201},
Key = {95062736916}
}
@article{5207875,
Author = {Sun, P-C and Fainman, Y and Mazurenko, YT and Brady,
DJ},
Title = {Space-time processing with photorefractive volume
holography},
Journal = {Proc. Spie Int. Soc. Opt. Eng. (Usa)},
Volume = {2529},
Pages = {157-170},
Address = {San Diego, CA, USA},
Year = {1995},
url = {http://dx.doi.org/10.1117/12.217003},
Keywords = {data conversion;high-speed optical techniques;holographic
storage;image matching;image reconstruction;matched
filters;optical dispersion;optical information
processing;optical interconnections;photorefractive
effect;},
Abstract = {Photorefractive volume holography for processing ultrashort
optical pulses carrying spatial, temporal and
spatio-temporal optical information is introduced. These new
holographic methods can process 4-dimensional information
that in addition to the 3 spatial coordinates also include
the temporal evolution of optical signals on nanosecond to
femtosecond scale. Photorefractive volume holographic
materials provide the medium necessary for recording and
reconstruction in real-time. Applications of direct time
domain and spectral domain holography for image processing,
temporal matched filtering, optical pulse shaping, 3-D
optical storage, and optical interconnects are discussed.
Furthermore, the combined space-time holographic processing
that allows the conversion between spatial and temporal
optical information carrying channels is introduced. This
method is used to demonstrate experimentally
parallel-to-serial and serial-to-parallel data conversion
for 1-D images and image-format data transmission. This
holographic processors provide the advantages of
self-referenced signal transmission and self-compensation
for optical dispersion induced by the holographic materials,
communication channel, as well as other optical components.
Finally, future research directions for optical information
processing with complex spatio-temporal signals are
identified and discussed},
Doi = {10.1117/12.217003},
Key = {5207875}
}
@article{fds280294,
Author = {Purchase, KG and Brady, DJ},
Title = {Dispersion compensation in coherence domain multiplexed
communications systems},
Journal = {Ieee Leos Annual Meeting Proceedings},
Volume = {1},
Pages = {196-197},
Year = {1994},
Month = {December},
Abstract = {We demonstrate dispersion compensation in coherence domain
multiplexed (CDM) systems by transmitting three 100 fs
signal pulses and a reference pulse in a packet through an
optical fiber. In CDM systems, detection of bits is
independent of dispersion, but the received packets must
still be recognizable. In this case, the separation between
packets must be at least as large as the dispersed width of
the received packets. The linear-dispersion limited
bandwidth of a CDM system exceeds that of a serial system by
a factor of √N/2, where N is the number of bits per
packet.},
Key = {fds280294}
}
@article{95022598602,
Author = {Michielssen, E and Brady, DJ},
Title = {Control of spatial excitation patterns in two-level systems
by use of time-domain fields},
Journal = {Optics Letters},
Volume = {19},
Number = {23},
Pages = {1931-1933},
Publisher = {The Optical Society},
Year = {1994},
Month = {December},
url = {http://dx.doi.org/10.1364/OL.19.001931},
Keywords = {Nonlinear optics;Time domain analysis;Optical resolving
power;Image recording;Image coding;Optimization;Algorithms;Molecules;Quantum
theory;},
Abstract = {Spatial structures created by pulsed field interactions with
surface-bound two-level systems are considered.
Superresolved pattern formation is possible by the use of
extra degrees of freedom programmed in the time-domain
field. © 1994 Optical Society of America.},
Doi = {10.1364/OL.19.001931},
Key = {95022598602}
}
@article{94081353383,
Author = {Tarkka, RM and Talbot, ME and Brady, DJ and Schuster,
GB},
Title = {Holographic storage in a near-ir sensitive photochromic
dye},
Journal = {Optics Communications},
Volume = {109},
Number = {1-2},
Pages = {54-58},
Publisher = {Elsevier BV},
Year = {1994},
Month = {June},
ISSN = {0030-4018},
url = {http://dx.doi.org/10.1016/0030-4018(94)90737-4},
Keywords = {Holography;Dyes;Photochromism;Optical systems;Holograms;Sensitivity
analysis;Fabrication;Optical testing;Optical
materials;Ultraviolet radiation;},
Abstract = {Application of a near infra-red sensitive
spirothiopyran/merocyanine system to dynamic volume
holographic data storage is considered. ©
1994.},
Doi = {10.1016/0030-4018(94)90737-4},
Key = {94081353383}
}
@article{95032607719,
Author = {Purchase, KG and Hill, KB and Talbot, ME and Brady,
DJ},
Title = {Dispersion compensation in coherence-domain multiplexed
systems},
Journal = {Optics Letters},
Volume = {19},
Number = {15},
Pages = {1107-1109},
Publisher = {The Optical Society},
Year = {1994},
Month = {January},
url = {http://dx.doi.org/10.1364/OL.19.001107},
Keywords = {Optical systems;Optical communication;Signal receivers;Light
sources;Interferometry;},
Abstract = {An ultrahigh-bandwidth point-to-point communications system
based on white-light sources, pulse shapers, and
interferometric receivers is proposed. Dispersion
compensation by interferometric receivers is described and
demonstrated. Linear dispersion-limited communications
bandwidths are shown to scale with the square root of the
data packet length. © 1994 Optical Society of
America.},
Doi = {10.1364/OL.19.001107},
Key = {95032607719}
}
@article{fds330771,
Author = {Brady, D and Catipovic, JA},
Title = {Adaptive Multiuser Detection for Underwater Acoustical
Channels},
Journal = {Ieee Journal of Oceanic Engineering},
Volume = {19},
Number = {2},
Pages = {158-165},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1994},
Month = {January},
url = {http://dx.doi.org/10.1109/48.286637},
Abstract = {An underwater acoustic local area network (ALAN) provides
multipoint-to-point telemetry between many high-rate,
ocean-bottom sensors and a central, surface-deployed
receiver in the 10–30 kHz vertical acoustical channel.
Ocean-bottom modems initiate the transmission process by
requesting data channel time slots via a common narrow band
request channel. Request packets overlap in time and
frequency in this channel, and the throughput and average
transmission delay rely heavily on the successful resolution
of the request packet collisions. This paper presents the
design, analysis, and experimental demonstration of a
request channel receiver capable of resolving collisions
between several asynchronous and cochannel packets. The
receiver algorithm differs from standard capture schemes (by
demodulating the data from both strong and weak
transmitters), conventional spread-spectrum receivers (by
overcoming the near–far problem), and existing
multiple-access demodulation techniques (by adapting to the
number of interfering signals, and the unknown phase,
Doppler, amplitude, and timing of each signal in the
collision). The receiver demodulates the collided packets by
decision-directed techniques through a novel method of
estimating the interference for each user which minimizes
error propagation due to inaccurate tentative decisions. An
inwater experiment illustrates that this technique is
extremely desirable for collision resolution in underwater
acoustic local area networks, and also for underwater
autonomous vehicles with both sidescan sonar as well as
acoustic telemetry links. © 1994 IEEE},
Doi = {10.1109/48.286637},
Key = {fds330771}
}
@article{fds330772,
Author = {Zvonar, Z and Brady, D},
Title = {Multiuser Detection in Single-Path Fading
Channels},
Journal = {Ieee Transactions on Communications},
Volume = {42},
Number = {234},
Pages = {1729-1739},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1994},
Month = {January},
url = {http://dx.doi.org/10.1109/TCOMM.1994.582881},
Abstract = {In this paper the performance analysis of maximum likelihood
sequence and decorrelating multiuser detectors is developed
for the single-path Rayleigh fading channel. The received
signal in this multipoint-to-point channel is additively
composed of white Gaussian noise and independently faded
waveforms from a finite number of asynchronous users. The
optimum sequence detector consists of a bank of single-user
matched filters followed by a dynamic programming algorithm,
has a demodulation complexity per symbol which is
exponential in the number of users, and requires the
knowledge of the system as well of the fading parameters.
The decorrelating detector has a complexity which is
polynomial in the number of users, and does not require
knowledge of the signal amplitudes, which are assumed to
vary slowly relative to the symbol rate. The single-user
error rates are presented for both detectors and compared to
conventional detection and isolated transmission, and the
notion of asymptotic multiuser efficiency is developed for
this channel. In contrast to conventional detection, which
suffers from near-far effects due to Rayleigh fading, it is
shown that the aforementioned multiuser detectors exhibit
performance which rivals that of isolated transmission for
sufficiently small thermal noise power. The results of this
analysis are illustrated with numerical examples and
indicate that the near-far problem may be alleviated by a
more sophisticated receiver design. © 1994
IEEE.},
Doi = {10.1109/TCOMM.1994.582881},
Key = {fds330772}
}
@article{95022583857,
Author = {Guo, JP and Ramachandran, S and Bishop, SG and Brady,
DJ},
Title = {Characterization of waveguide and grating formation in
As2S3},
Journal = {Ieee Leos Annual Meeting Proceedings},
Volume = {2},
Pages = {139-140},
Address = {Boston, MA, USA},
Year = {1994},
url = {http://dx.doi.org/10.1109/LEOS.1994.586362},
Keywords = {Optical waveguides;Diffraction gratings;Glass;Arsenic
compounds;Characterization;Refractive index;Surfaces;Gas
lasers;Light modulation;Optical variables
measurement;Fabrication;Laser beams;},
Abstract = {Photodarkening in the chalcogenide glass As2S3 makes it
attractive for applications in integrated optics and data
storage Various optical devices can be fabricated using the
laser-induced change of refractive index in this material.
Waveguides, directional couplers, and holographic gratings
have been fabricated on thin films and bulk samples of
As2S3. This paper reports studies of the dynamics of
waveguide and grating formation on the surface of bulk
As2S3. Spatial and temporal characteristics of laser-induced
refractive index changes are described. Several different
material effects are shown to contribute to the index
modulation.},
Key = {95022583857}
}
@article{95032607029,
Author = {Basinger Scott and A and Brady David and J},
Title = {Finite-difference time-domain modeling of dispersive
nonlinear Fabry-Perot cavities},
Journal = {Journal of the Optical Society of America B: Optical
Physics},
Volume = {11},
Number = {8},
Pages = {1504-1511},
Publisher = {The Optical Society},
Year = {1994},
url = {http://dx.doi.org/10.1364/JOSAB.11.001504},
Keywords = {Finite difference method;Mathematical models;Numerical
analysis;Dielectric materials;Metals;Light
absorption;},
Abstract = {This paper proves that finite-difference time-domain (FD-TD)
algorithms can be applied for the analysis of time-domain
response of nonlinear Fabry-Perot cavities, and time-domain
pulse selectivity obtained. The energy absorbed from various
pulse shapes by a given nonlinear cavity is calculated,
since a pulse-selective cavity will absorb significantly
more energy from the selected pulse shapes than from random
pulses with similar spectra.},
Doi = {10.1364/JOSAB.11.001504},
Key = {95032607029}
}
@article{4729819,
Author = {Chen, AG and Brady, DJ},
Title = {Electrically controlled multiple hologram
storage},
Journal = {Opt. Mem. Neural Netw. (Usa)},
Volume = {3},
Number = {2},
Pages = {129-133},
Year = {1994},
Keywords = {electro-optical devices;holographic storage;liquid crystal
devices;optical modulation;},
Abstract = {Gated techniques for selectively addressing limited regions
in volume storage systems are considered. An experimental
system which selectively addresses layers in a volume using
polarization sensitive holograms and liquid crystal
modulator is described},
Key = {4729819}
}
@article{94041259125,
Author = {Brady, D and Hill, K and Basinger, S},
Title = {Holographic pulse shaping in organic media},
Journal = {Conference Proceedings Lasers and Electro Optics Society
Annual Meeting},
Pages = {112-113},
Address = {San jose, CA, USA},
Year = {1993},
Month = {December},
url = {http://dx.doi.org/10.1109/LEOS.1993.379106},
Keywords = {Laser mode locking;Optical materials;Nonlinear optics;Laser
pulses;Interferometers;},
Abstract = {In our system the index modulation is formed by cis-trans
isomerization of an azo-dye in an organic matrix. The index
modulation is recorded by 514 nm light. Data is encoded on
the reflection grating by spatially modulating one of the
recording beams. The holographic recording time is about 1
second and the dark decay time is several minutes. By
matching the temporal structure of the driving field to the
natural spatial or quantum resonances of a nonlinear system
it is possible to strongly enhance nonlinear effects.
Applications of this approach to optical switching and
numerical simulations of shaped pulse propagation in
nonlinear media are presented.},
Key = {94041259125}
}
@article{93081657234,
Author = {Chen, AG and Brady, DJ},
Title = {Two-wavelength reversible holograms in azo-dye doped nematic
liquid crystals},
Journal = {Applied Physics Letters},
Volume = {62},
Number = {23},
Pages = {2920-2922},
Publisher = {AIP Publishing},
Year = {1993},
Month = {December},
ISSN = {0003-6951},
url = {http://dx.doi.org/10.1063/1.109197},
Abstract = {We describe reversible holographic effects in azo-dye doped
liquid crystals. Surface-stabilized holograms are recorded
at 514 nm using beams polarized parallel to the molecular
director of the liquid crystals. While these holograms
persist for several hours in the dark, complete erasure is
achieved in a few seconds by exposure to 337 nm
light.},
Doi = {10.1063/1.109197},
Key = {93081657234}
}
@article{fds280293,
Author = {Brady, D and Psaltis, D},
Title = {Information capacity of 3-D holographic data
storage},
Journal = {Optical and Quantum Electronics},
Volume = {25},
Number = {9},
Pages = {S597-S610},
Publisher = {Springer Nature America, Inc},
Year = {1993},
Month = {September},
ISSN = {0306-8919},
url = {http://dx.doi.org/10.1007/BF00444333},
Abstract = {Capacities for angular and wavelength multiplexed
holographic data storage systems are considered. Limitations
due to the spatial resolution of the recording and
reconstructing fields and to the holographic recording
process are derived. © 1993 Chapman & Hall.},
Doi = {10.1007/BF00444333},
Key = {fds280293}
}
@article{94051282986,
Author = {Hill, KB and Brady, DJ},
Title = {Impulse responses of strong reflection holograms},
Journal = {Applied Optics},
Volume = {32},
Number = {23},
Pages = {4305-4316},
Publisher = {The Optical Society},
Year = {1993},
Month = {August},
url = {http://dx.doi.org/10.1364/AO.32.004305},
Keywords = {Scattering;Numerical methods;Optical devices;Reflection;},
Abstract = {Strong scattering in broad spatial bandwidth reflection
holograms is analyzed by using numerical techniques.
Transfer functions and impulse responses for various index
modulations are found, and techniques for constructing
holograms for optical pulse shaping, coding, and dispersion
compensation are discussed. © 1993 Optical Society of
America.},
Doi = {10.1364/AO.32.004305},
Key = {94051282986}
}
@article{94091388706,
Author = {Howe, AT and Papen, GC and Murphy, GM and Dallesasse, JM and Dejule, RY and Brady, DJ and Holmgren, DJ},
Title = {Multiple-wavelength operation of a laser-diode array coupled
to an external cavity},
Journal = {Optics Letters},
Volume = {18},
Number = {17},
Pages = {1441-1443},
Publisher = {The Optical Society},
Year = {1993},
Month = {January},
url = {http://dx.doi.org/10.1364/OL.18.001441},
Keywords = {Semiconductor diodes;Cavity resonators;Laser tuning;Optical
data storage;Spectroscopy;Frequency division
multiplexing;},
Abstract = {We report a novel geometry for coupling a laser-diode array
to an external cavity that produces a diffractively
stabilized lasing wavelength separation between elements of
the array. The geometry allows for control of the
wavelengths and wavelength spacing and provides single-knob
tuning of all the wavelengths while maintaining a nearly
constant wavelength offset. © 1993 Optical Society of
America.},
Doi = {10.1364/OL.18.001441},
Key = {94091388706}
}
@article{94071337774,
Author = {Brady, D and Papen, G and Sipe, JE},
Title = {Spherical distributed dielectric resonators},
Journal = {Journal of the Optical Society of America B: Optical
Physics},
Volume = {10},
Number = {4},
Pages = {646-657},
Publisher = {The Optical Society},
Year = {1993},
url = {http://dx.doi.org/10.1364/JOSAB.10.000644},
Keywords = {Optical resonators;Electromagnetic field effects;Numerical
analysis;Mathematical models;Modulation;Electromagnetic wave
propagation;},
Abstract = {This paper discusses the classical theory of
electromagnetism for spherical distributed dielectric
resonators. It is postulated that for complete solid angles,
these structures inhibit propagation for a finite frequency
range, whose range is linear in amplitude of radial
modulation. A numerical analysis of the scattering and
internal field distribution is described.},
Doi = {10.1364/JOSAB.10.000644},
Key = {94071337774}
}
@article{4600541,
Author = {Purchase, KG and Brady, DJ and Wagner, K},
Title = {Time-of-flight cross correlation on a detector array for
ultrafast packet detection},
Journal = {Opt. Lett. (Usa)},
Volume = {18},
Number = {24},
Pages = {2129-2131},
Publisher = {The Optical Society},
Year = {1993},
url = {http://dx.doi.org/10.1364/OL.18.002129},
Keywords = {high-speed optical techniques;optical correlation;optical
receivers;photodetectors;},
Abstract = {We describe and demonstrate an interferometric technique for
measuring the first-order cross correlation of ultrafast
optical pulses. This technique may permit single-shot pulse
detection and is applicable to receivers for time-domain
optical communications},
Doi = {10.1364/OL.18.002129},
Key = {4600541}
}
@article{4527936,
Author = {Hill, KB and Brady, DJ},
Title = {Pulse shaping in volume reflection holograms},
Journal = {Opt. Lett. (Usa)},
Volume = {18},
Number = {20},
Pages = {1739-1741},
Publisher = {The Optical Society},
Year = {1993},
url = {http://dx.doi.org/10.1364/OL.18.001739},
Keywords = {high-speed optical techniques;holography;light
reflection;optical resolving power;},
Abstract = {Ultrashort pulses are shaped by reflection from dynamic
volume holograms recorded in azo-dye-doped epoxies. The
spectral resolution and controllability of the reflection
geometry are optimal for this application},
Doi = {10.1364/OL.18.001739},
Key = {4527936}
}
@article{fds323380,
Author = {Brady, D and Chen, AGS and Rodriguez, G},
Title = {Volume holographic pulse shaping},
Journal = {Optics Letters},
Volume = {17},
Number = {8},
Pages = {610-612},
Publisher = {The Optical Society},
Year = {1992},
Month = {April},
url = {http://dx.doi.org/10.1364/OL.17.000610},
Abstract = {Volume holograms for subpicosecond pulse shaping are
described. Experimental results with a camphorquinone-doped
plastic hologram probed by a colliding-pulse mode-locked
laser are presented. We observe a 2-THz beat frequency in
the diffracted pulse. © 1992 Optical Society of
America.},
Doi = {10.1364/OL.17.000610},
Key = {fds323380}
}
@article{fds323379,
Author = {Brady, D and Psaltis, D},
Title = {Control of volume holograms},
Journal = {Journal of the Optical Society of America
A},
Volume = {9},
Number = {7},
Pages = {1167-1182},
Publisher = {The Optical Society},
Year = {1992},
Month = {January},
url = {http://dx.doi.org/10.1364/JOSAA.9.001167},
Abstract = {The mismatch in the number of degrees of freedom supported
by volume holograms and the boundary fields that control
them limits the dynamic range of recorded holograms. For
holograms controlled by using fractal sampling grids, the
maximum dynamic range falls inversely with the minimum
number of exposures needed to record the hologram, the rank
of the hologram. In adaptive holography, feedback between
coupled holograms prevents the dynamic range from decreasing
faster than the fundamental limit. If the control problem is
overcome, the maximum dynamic range that a hologram can
support falls inversely with the square root of the rank. In
principle, holograms in which the dynamic range falls
inversely with the square root of the rank can be recorded
by using cross-spectrally coherent polychromatic pulses. ©
1992 Optical Society of America.},
Doi = {10.1364/JOSAA.9.001167},
Key = {fds323379}
}
@article{4147817,
Author = {Chen, AG and Brady, DJ},
Title = {Real-time holography in azo-dye-doped liquid
crystals},
Journal = {Opt. Lett. (Usa)},
Volume = {17},
Number = {6},
Pages = {441-443},
Publisher = {The Optical Society},
Year = {1992},
url = {http://dx.doi.org/10.1364/OL.17.000441},
Keywords = {holography;nematic liquid crystals;optical materials;organic
compounds;},
Abstract = {When exposed to an Ar laser at 514 nm, azo-dye molecules in
a nematic liquid-crystal host undergo photoisomerization
from trans-isomers to cis-isomers. The conformation change
of the azo-dye molecules reorients liquid-crystal molecules.
Reversible polarization holograms can be recorded
dynamically by this effect, with a threshold intensity as
low as 3.0 mW/cm2 and a response time from a few hundred
microseconds to 100 ms, depending on the spatial frequency
of the recorded grating},
Doi = {10.1364/OL.17.000441},
Key = {4147817}
}
@article{92020412384,
Author = {Chen, GS and Brady, DJ},
Title = {Liquid-crystal-doped polymers as volume holographic
elements},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {1562},
Pages = {128-135},
Address = {San Diego, CA, USA},
Year = {1991},
Month = {December},
Keywords = {Crystals, Liquid - Nematic;Holography;Polymers -
Doping;Interferometry;Molecules;},
Abstract = {Nematic liquid crystal molecules doped into polymer matrices
are investigated for holographic information storage.
Holographic effects due to thermal and optically driven
anisotropies are observed.},
Key = {92020412384}
}
@article{3945827,
Author = {Brady, DJ and Psaltis, D},
Title = {Holographic interconnections in photorefractive
waveguides},
Journal = {Appl. Opt. (Usa)},
Volume = {30},
Number = {17},
Pages = {2324-2333},
Publisher = {The Optical Society},
Year = {1991},
url = {http://dx.doi.org/10.1364/AO.30.002324},
Keywords = {digital arithmetic;holography;integrated optics;optical
interconnections;optical logic;optical waveguides;photorefractive
materials;},
Abstract = {An architecture for implementing large scale holographic
interconnections in photorefractive waveguides is described.
Methods for controlling the hologram using unguided light
are considered and experimentally demonstrated},
Doi = {10.1364/AO.30.002324},
Key = {3945827}
}
@article{91040180071,
Author = {Brady, D and Verdu, S},
Title = {A semiclassical analysis of optical code division multiple
access},
Journal = {Ieee Transactions on Communications},
Volume = {39},
Number = {1},
Pages = {85-93},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1991},
url = {http://dx.doi.org/10.1109/26.68279},
Keywords = {Signal Interference;Probability - Random Processes;Signal
Receivers;Signal Filtering and Prediction;Mathematical
Techniques - Error Analysis;},
Abstract = {A model noncoherent, optical, asynchronous, code-division
multiple-access (CDMA) system is described. The error rate
for a single-user matched-filter receiver that is valid for
arbitrary photomultipliers and signature sequence sets,
adheres to the semiclassical model of light, and does not
depend on approximations for large user groups, strong
received optical fields, or chip synchronism is analyzed.
The exact minimum probability of error and optimal threshold
are compared to those obtained with user-synchronism and
multiple-access interference (MAI) distribution
approximations. For the special case of unity-gain
photodetectors and prime sequences, it is shown that the
approximation of chip synchronism yields a weak upper bound
on the exact error rate. It is demonstrated that the
approximations of perfect optical-to-electrical conversion
and Gaussian-distributed MAI yield a poor approximation to
the minimum error rate and an underestimate of the optimal
threshold. Arbitrarily tight bounds are developed on the
error rate for unequal energies per bit. In the case when
the signal energies coincide, these bounding expressions are
considerably easier to compute than the exact error
rate.},
Doi = {10.1109/26.68279},
Key = {91040180071}
}
@article{fds323381,
Author = {Brady, D and Hsu, K and Psaltis, D},
Title = {Periodically refreshed multiply exposed photorefractive
holograms},
Journal = {Optics Letters},
Volume = {15},
Number = {14},
Pages = {817-819},
Publisher = {The Optical Society},
Year = {1990},
Month = {July},
url = {http://dx.doi.org/10.1364/OL.15.000817},
Abstract = {We describe a method for increasing the diffraction
efficiency of multiply exposed photorefractive holograms by
periodic copying. The method is experimentally demonstrated
with photorefractive and thermoplastic recording media. ©
1990 Optical Society of America.},
Doi = {10.1364/OL.15.000817},
Key = {fds323381}
}
@article{fds330778,
Author = {Hong, JH and Yeh, P and Psaltis, D and Brady, D},
Title = {Diffraction efficiency of strong volume holograms},
Journal = {Optics Letters},
Volume = {15},
Number = {6},
Pages = {344-346},
Publisher = {The Optical Society},
Year = {1990},
Month = {March},
url = {http://dx.doi.org/10.1364/OL.15.000344},
Abstract = {We investigate the diffraction efficiency of strong volume
holograms in which the coupling parameter is several times
that needed for maximum diffraction efficiency. We discuss
the implications of our findings on photorefractive
implementations of various neural network systems. © 1990
Optical Society of America.},
Doi = {10.1364/OL.15.000344},
Key = {fds330778}
}
@article{fds280392,
Author = {Psaltis, D and Brady, D and Gu, XG and Lin, S},
Title = {Holography in artificial neural networks.},
Journal = {Nature},
Volume = {343},
Number = {6256},
Pages = {325-330},
Year = {1990},
Month = {January},
ISSN = {0028-0836},
url = {http://dx.doi.org/10.1038/343325a0},
Abstract = {The dense interconnections that characterize neural networks
are most readily implemented using optical signal
processing. Optoelectronic 'neurons' fabricated from
semiconducting materials can be connected by holographic
images recorded in photorefractive crystals. Processes such
as learning can be demonstrated using holographic optical
neural networks.},
Doi = {10.1038/343325a0},
Key = {fds280392}
}
@article{fds280393,
Author = {Brady, D},
Title = {Switching arrays make light work in a simple
processor},
Journal = {Nature},
Volume = {344},
Number = {6266},
Pages = {486-487},
Publisher = {Springer Nature},
Year = {1990},
Month = {January},
ISSN = {0028-0836},
url = {http://dx.doi.org/10.1038/344486a0},
Doi = {10.1038/344486a0},
Key = {fds280393}
}
@article{fds330779,
Author = {Yu, J and Johnston, A and Psaltis, D and Brady, D},
Title = {Limitations of opto-electronic neural networks},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {1053},
Pages = {40-51},
Publisher = {SPIE},
Year = {1989},
Month = {June},
url = {http://dx.doi.org/10.1117/12.951514},
Abstract = {Neural networks are composed of three components: Neurons,
weights, and connections. Limitation on implementing these
components in electronics and optics are discussed. We show
that using electronically fabricated neurons and a
combination of optics and electronics for the weights and
connections efficiently utilizes the advantage of each
technology. The choice of the technology used to implement
the weights and connections depends on the type of neural
network being built. © 1989 SPIE.},
Doi = {10.1117/12.951514},
Key = {fds330779}
}
@article{fds323382,
Author = {Psaltis, D and Gu, XG and Brady, D},
Title = {Fractal sampling grids for holographic interconnections},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {963},
Pages = {468-474},
Publisher = {SPIE},
Year = {1989},
Month = {February},
url = {http://dx.doi.org/10.1117/12.947926},
Abstract = {The optical implementation of weighted interconnections is
investigated and basic relationships are derived between the
number of neurons, the number of connections and the size of
the optical system that is used to perform the connections.
Specific methods for selecting the positions of the neurons
to achieve the maximum density of independent connections
are presented. © 1989 SPIE.},
Doi = {10.1117/12.947926},
Key = {fds323382}
}
@article{90046020621,
Author = {Psaltis, D and Yamamura, AA and Hsu, K and Lin, S and Gu, XG and Brady,
D},
Title = {Optoelectronic Implementations of Neural
Networks},
Journal = {Ieee Communications Magazine},
Volume = {27},
Number = {11},
Pages = {37-40},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1989},
Month = {January},
url = {http://dx.doi.org/10.1109/35.41399},
Keywords = {Optoelectronic Devices;Holography;Optical Data
Processing;Data Storage, Optical;},
Abstract = {The ability of optical systems to provide the massive
interconnections between processors required in most neural
network models, which constitutes their chief advantage for
such applications, is discussed, focusing on holography.
Because of the essential nonlinearity of the holographic
connections, nonlinear processing elements are needed to
perform complex computations. The use of GaAs hybrid
optoelectronic processing elements is examined. GaAs is an
excellent material for this purpose, since it can be used to
fabricate both fast electronic circuits and optical sources
and detectors. It is shown how a complete hybrid neural
computer can be implemented using available technology
developed for conventional computing. An experimentally
demonstrated network in which optics plays an even larger
role is described.},
Doi = {10.1109/35.41399},
Key = {90046020621}
}
@article{fds330780,
Author = {Brady, D and Verdú, S},
Title = {Performance Analysis Of An Asymptotically Quantum-Limited
Optical Dpsk Receiver},
Journal = {Ieee Transactions on Communications},
Volume = {37},
Number = {1},
Pages = {46-51},
Year = {1989},
Month = {January},
url = {http://dx.doi.org/10.1109/26.21652},
Abstract = {In this paper, we analyze an optical, direct-detection DPSK
receiver whose error probability is quantum-limited as the
transmitting laser linewidth vanishes. The receiver design
is based on a binary equiprobable hypothesis test with
doubly stochastic point process observations, the
conditional random rates of which depend on the transmitting
laser phase noise, which is modeled as a Brownian motion.
The receiver structure consists of a simple, delay-and-sum
optical preprocessor followed by a photoelectric converter
and an integrate-and-dump circuit. Upper and lower bounds on
the receiver bit error rate are derived by developing bounds
on the conditional rates of the point process, and it is
shown that the error probability bounds converge to the true
value as the transmitting laser linewidth decreases. Bounds
on the power penalty are computed for parameters
corresponding to existing semiconductor injection lasers,
and are seen to be less than the limiting power penalty for
the balanced DPSK receiver. © 1989 IEEE},
Doi = {10.1109/26.21652},
Key = {fds330780}
}
@article{fds330782,
Author = {Brady, D and Gu, XG and Psaltis, D},
Title = {Photorefractive crystals in optical neural
computers},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {882},
Pages = {132-136},
Publisher = {SPIE},
Year = {1988},
Month = {May},
url = {http://dx.doi.org/10.1117/12.944112},
Abstract = {The storage capacity for neural interconnections in
photorefractive crystals and the use of the dynamic nature
of the photorefractive effect to train these
interconnections are discussed. We describe an optical
neural architecture which uses the characteristics of the
photorefractive response to implement error driven learning
and describe a modified perceptron algorithm which we have
used to train this optical system. © 1988
SPIE.},
Doi = {10.1117/12.944112},
Key = {fds330782}
}
@article{fds323384,
Author = {Psaltis, D and Brady, D},
Title = {A photorefractive integrated optical vector matrix
multiplier},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {825},
Pages = {106-113},
Publisher = {SPIE},
Year = {1988},
Month = {February},
url = {http://dx.doi.org/10.1117/12.941992},
Abstract = {A method for implementing general linear transformations on
one dimensional optical field distributions in integrated
optics is described. This method uses the Bragg selectivity
of volume holograms to replace one dimension of the bulk
optical vector matrix multiplier. A means of writing
appropriate matrices optically using unguided light is also
described. Experimental results are presented which
demonstrate the diffraction of guided light by holograms
written with unguided beams. © 1988 SPIE.},
Doi = {10.1117/12.941992},
Key = {fds323384}
}
@article{fds280391,
Author = {David, B},
Title = {Dynamic holographic interconnections for optical neural
computers},
Journal = {Neural Networks : the Official Journal of the International
Neural Network Society},
Volume = {1},
Number = {1 SUPPL},
Pages = {374},
Publisher = {Elsevier BV},
Year = {1988},
Month = {January},
ISSN = {0893-6080},
url = {http://dx.doi.org/10.1016/0893-6080(88)90400-5},
Abstract = {A neural system comprised of p neurons with c
interconnections per neuron requires cp degrees of freedom
in its interconnections. If these interconnections are
formed by interactions between narrow-band signals emitted
by the p active elements, only p degrees of freedom are
available at any given instant for modifying the
interconnections. Thus a full and independent update of the
interconnections requires that they be addressed c times.
Constraints of this sort are natural to volume holography.
While the number of interconnections which may be stored in
a volume hologram scales as the volume of the system, N3,
the number of optical beams which may be used to record
holograms scales as the area enclosing the system, N2. This
means that in holographic systems cp ≤ N3 and p ≤ N2.
High density storage of holographic interconnections is
therefore by necessity a dynamic process. The authors have
developed dynamic recording processes which use
photorefractive holography to record cp independent
interconnections using p inputs. In implementing an optical
neural architecture they use their control over the signals
emitted by the p active elements to force the system to an
interconnection pattern consistent with the needs of the
neural system.},
Doi = {10.1016/0893-6080(88)90400-5},
Key = {fds280391}
}
@article{fds323383,
Author = {Psaltis, D and Brady, D and Wagner, K},
Title = {Adaptive optical networks using photorefractive
crystals},
Journal = {Applied Optics},
Volume = {27},
Number = {9},
Pages = {1752-1759},
Publisher = {The Optical Society},
Year = {1988},
Month = {January},
url = {http://dx.doi.org/10.1364/AO.27.001752},
Abstract = {The capabilities of photorefractive crystals as media for
holographic interconnections in neural networks are
examined. Limitations on the density of interconnections and
the number of holographic associations which can be stored
in photorefractive crystals are derived. Optical
architectures for implementing various neural schemes are
described. Experimental results are presented for one of
these architectures. © 1988 Optical Society of
America.},
Doi = {10.1364/AO.27.001752},
Key = {fds323383}
}
@article{88110162590,
Author = {Psaltis, D and Wagner, K and Brady, D},
Title = {LEARNING IN OPTICAL NEURAL COMPUTERS.},
Pages = {iii/549-iii/555},
Address = {San Diego, CA, USA},
Year = {1987},
Month = {December},
Keywords = {HOLOGRAPHY;SYSTEMS SCIENCE AND CYBERNETICS - Learning
Systems;OPTICAL GRATINGS;},
Abstract = {The authors consider the optical implementation of learning
networks using volume holographic interconnections in
photorefractive crystals. The use of volume holograms
permits the storage of a very large number of
interconnections per unit volume, and the use of
photorefractive crystals permits the dynamic modification of
these connections, thus allowing the implementation of
learning algorithms. The authors first briefly review the
major types of learning algorithms that are being used in
neural network models. They then estimate the maximum number
of holographic gratings that can simultaneously exist in a
photorefractive crystal. Since in an optical implementation
each grating corresponds to a separate interconnection
between two neurons, this estimate gives the density of
connections that are achievable. They consider how the
modulation depth of each grating (or equivalently the
strength of each connection) can be controlled through the
implementation of learning algorithms. Two related issues
are investigated: the optical architectures that implement
different learning algorithms and the reconciliation of
physical mechanisms that are involved in the recording of
holograms in photorefractive crystals with the dynamics of
the learning procedures in neural networks.},
Key = {88110162590}
}
@article{7909777,
Author = {Gopinathan, U. and Brady, D.J. and Pitsianis,
N.P.},
Title = {Coded apertures for efficient pyroelectric motion
tracking},
Journal = {Opt. Express (USA)},
Volume = {11},
Number = {18},
Year = {8},
Keywords = {image motion analysis;infrared detectors;infrared
imaging;optical design techniques;optical elements;optical
information processing;optical sensors;optical
tracking;pyroelectric detectors;},
Abstract = {Coded apertures may be designed to modulate the visibility
between source and measurement spaces such that the position
of a source among N resolution cells may be discriminated
using logarithm of N measurements. We use coded apertures as
reference structures in a pyroelectric motion tracking
system. This sensor system is capable of detecting source
motion in one of the 15 cells uniformly distributed over a
1.6 m × 1.6 m domain using 4 pyroelectric
detectors},
Key = {7909777}
}
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