Open Access

Activity Representation Using 3D Shape Models

  • MohamedF Abdelkader1Email author,
  • AmitK Roy-Chowdhury2,
  • Rama Chellappa1 and
  • Umut Akdemir3
EURASIP Journal on Image and Video Processing20072008:347050

Received: 1 February 2007

Accepted: 25 November 2007

Published: 6 December 2007


We present a method for characterizing human activities using 3D deformable shape models. The motion trajectories of points extracted from objects involved in the activity are used to build models for each activity, and these models are used for classification and detection of unusual activities. The deformable models are learnt using the factorization theorem for nonrigid 3D models. We present a theory for characterizing the degree of deformation in the 3D models from a sequence of tracked observations. This degree, termed as deformation index (DI), is used as an input to the 3D model estimation process. We study the special case of ground plane activities in detail because of its importance in video surveillance applications. We present results of our activity modeling approach using videos of both high-resolution single individual activities and ground plane surveillance activities.


Surveillance ActivityGround PlaneMotion TrajectoryShape ModelVideo Surveillance

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Authors’ Affiliations

Department of Electrical and Computer Engineering and Center for Automation Research, UMIACS, University of Maryland, College Park, USA
Department of Electrical Engineering, University of California, Riverside, USA
Siemens Corporate Research, Princeton, USA


© Mohamed F. Abdelkader et al. 2008

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.