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Optical Engineering

Detection of unusual optical flow patterns by multilevel hidden Markov models
Author(s): Ákos Utasi; László Czúni
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Paper Abstract

The analysis of motion information is one of the main tools for the understanding of complex behaviors in video. However, due to the quality of the optical flow of low-cost surveillance camera systems and the complexity of motion, new robust image-processing methods are required to generate reliable higher-level information. In our novel approach there is no need for tracking objects (vehicles, pedestrians) in order to recognize anomalous motion, but dense optical flow information is used to construct mixtures of Gaussians, which are analyzed temporally. We create a multilevel model, where low-level states of non-overlapping image regions are modeled by continuous hidden Markov models (HMMs). From low-level HMMs we compose high-level HMMs to analyze the occurrence of the low-level states. The processing of large numbers of data in traditional HMMs can result in a precision problem due to the multiplication of low probability values. Thus, besides introducing new motion models, we incorporate a scaling technique into the mathematical model of HMMs to avoid precision problems and to get an effective tool for the analysis of large numbers of motion vectors. We illustrate the use of our models with real-life traffic videos.

Paper Details

Date Published: 1 January 2010
PDF: 11 pages
Opt. Eng. 49(1) 017201 doi: 10.1117/1.3280284
Published in: Optical Engineering Volume 49, Issue 1
Show Author Affiliations
Ákos Utasi, Computer and Automation Research Institute (Hungary)
László Czúni, Univ. of Pannonia (Hungary)

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