Seminars/Colloquia/Invited Talks

Seminars

Mubarak Shah

Recognizing Actions, Objects, and Actions as Objects

PLACE:	Clark 110
EVENT:	CIS Seminar Series
DATE:	October 30, 2007
TIME:	1:00 - 2:00 PM

Abstract

Recognition of human actions from video sequences is a very popular in Computer Vision. Since an action takes place in 3-D, and is projected on a sequence of 2-D images, the projected 2-D motion may vary depending on the viewpoint of the camera. This creates a problem in recognizing human actions from 2D video sequence. In most current works on action recognition, the issue of view-invariance has been ignored. In this talk, I will present our work on human action recognition which uses geometry to deal with the problem of view invariance. Object recognition is a classic problem in computer vision, which has been popular in the community for the last thirty years. In the second part of my talk, I will present a novel multi-view generic object class recognition method based on 3D object modeling. Instead of using a complicated mechanism for relating multiple 2D training views, the proposed method establishes spatial connections between these views by attaching appearance features to the surfaces of 3D models. The 3D model is represented by a volume consisting of binary slices, and is generated by using a new homographic framework. When an actor performs an action in 3D, the points on the outer boundary of the actor are projected as 2D (x, y) contour in the image plane. A sequence of such 2D contours with respect to time generates a spatiotemporal volume (STV) in (x, y, t), which can be treated as 3D object in the (x, y, t) space. In the third part of this talk, I will present our approach for human recognition by treating actions as objects. We analyze STV by using the differential geometric surface properties, such as peaks, pits, valleys and ridges, which are important action descriptors capturing both spatial and temporal properties. A set of motion descriptors for a given action is called an action sketch. The action descriptors are related to various types of motions and object deformations.

Brief Biography:

Dr. Mubarak Shah, Agere Chair Professor of Computer Science, and the founding director of the Computer Visions Lab at the University of Central Florida, is a researcher in a number of computer vision areas. He has worked in several areas including activity and gesture recognition, violence detection, event ontology, object tracking, video segmentation, story and scene segmentation, view morphing, ATR, wide-baseline matching, and video registration. He is a co-author of two books (Motion-Based Recognition (1997) and Video Registration (2003)) both by Kluwer Academic Publisher. Dr. Shah is a fellow of IEEE and IAPR. In 2006, he was awarded a Pegasus Professor award, the highest award at UCF, given to a faculty member who has made a significant impact on the university, has made an extraordinary contribution to the university community, and has demonstrated excellence in teaching, research and service. He was an IEEE Distinguished Visitor speaker for 1997-2000 and received IEEE Outstanding Engineering Educator Award in 1997. He received the Harris Corporation's Engineering Achievement Award in 1999, the TOKTEN awards from UNDP in 1995, 1997, and 2000; Teaching Incentive Program award in 1995 and 2003, Research Incentive Award in 2003, Millionaires' Club awards in 2005 and 2006, University Distinguished Researcher award in 2007, honorable mention for the ICCV 2005 Where Am I? Challenge Problem, and was nominated for the best paper award in ACM Multimedia Conference in 2005. He is an editor of international book series on Video Computing; editor in chief of Machine Vision and Applications journal, and an associate editor of ACM Computing Surveys journal. He was an associate editor of the IEEE Transactions on PAMI, and a guest editor of the special issue of International Journal of Computer Vision on Video Computing.