Activity modelling in crowded environments : a soft decision approach

Xu, Jingxin, Denman, Simon, Sridharan, Sridha, & Fookes, Clinton B. (2011) Activity modelling in crowded environments : a soft decision approach. In The International Conference on Digital Image Computing : Techniques and Applications (DICTA2011), 6-8 December 2011, Sheraton Noosa Resort & Spa, Noosa, QLD.

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Probabilistic topic models have recently been used for activity analysis in video processing, due to their strong capacity to model both local activities and interactions in crowded scenes. In those applications, a video sequence is divided into a collection of uniform non-overlaping video clips, and the high dimensional continuous inputs are quantized into a bag of discrete visual words. The hard division of video clips, and hard assignment of visual words leads to problems when an activity is split over multiple clips, or the most appropriate visual word for quantization is unclear. In this paper, we propose a novel algorithm, which makes use of a soft histogram technique to compensate for the loss of information in the quantization process; and a soft cut technique in the temporal domain to overcome problems caused by separating an activity into two video clips. In the detection process, we also apply a soft decision strategy to detect unusual events.We show that the proposed soft decision approach outperforms its hard decision counterpart in both local and global activity modelling.

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2 citations in Scopus
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ID Code: 46300
Item Type: Conference Paper
Refereed: Yes
Keywords: crowded scenes, non-overlaping video clips
Subjects: Australian and New Zealand Standard Research Classification > INFORMATION AND COMPUTING SCIENCES (080000) > ARTIFICIAL INTELLIGENCE AND IMAGE PROCESSING (080100)
Divisions: Past > QUT Faculties & Divisions > Faculty of Built Environment and Engineering
Past > Institutes > Information Security Institute
Past > Schools > School of Engineering Systems
Copyright Owner: Copyright 2011 IEEE
Copyright Statement: Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Deposited On: 03 Oct 2011 22:06
Last Modified: 23 Jun 2015 05:46

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