Publications [#338864] of Lawrence Carin

Papers Published

1. Pruteanu-Malinici, I; Carin, L, Infinite hidden Markov models for unusual-event detection in video., IEEE transactions on image processing : a publication of the IEEE Signal Processing Society, vol. 17 no. 5 (May, 2008), pp. 811-822, ISSN 1057-7149 [doi]
   (last updated on 2024/12/31)

   Abstract:
   We address the problem of unusual-event detection in a video sequence. Invariant subspace analysis (ISA) is used to extract features from the video, and the time-evolving properties of these features are modeled via an infinite hidden Markov model (iHMM), which is trained using "normal"/"typical" video. The iHMM retains a full posterior density function on all model parameters, including the number of underlying HMM states. Anomalies (unusual events) are detected subsequently if a low likelihood is observed when associated sequential features are submitted to the trained iHMM. A hierarchical Dirichlet process framework is employed in the formulation of the iHMM. The evaluation of posterior distributions for the iHMM is achieved in two ways: via Markov chain Monte Carlo and using a variational Bayes formulation. Comparisons are made to modeling based on conventional maximum-likelihood-based HMMs, as well as to Dirichlet-process-based Gaussian-mixture models.