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A Solution to the Eye Contact Correction in Tele-presence Systems Open Access


Other title
stereo matching
eye contact correction
image matting
computer vision
Type of item
Degree grantor
University of Alberta
Author or creator
Supervisor and department
Boulanger,Pierre(Computing Science)
Examining committee member and department
Ray,Nilanjan(Computing Science)
Nasiopoulos,Panos (Electrical and Computer Engineering,UBC)
Zhao,Vicky(Electrical and Computer Engineering)
Jagersand,Martin(Computing Science)
Boulanger,Pierre(Computing Science)
Department of Computing Science

Date accepted
Graduation date
Doctor of Philosophy
Degree level
With the development of globalization, numerous tele-conferencing systems have been developed to shorten the distance between people. Tele-presence is one of these systems which can broadcast high-quality audio and video to remote sites trying to give the illusion to the participants that they are co-located in a common virtual meeting room. In order to provide this illusion, one main criterion is to maintain eye contact. This is important because eye contact can convey more information than languages sometimes and correct eye contact is one of the essential factors which make the participants feel like they are talking face-to-face. However, some of the successful methods to eye contact correction problem in tele-presence systems need special equipment which is either large or expensive. In this thesis, we propose a software-based solution to the eye contact correction problem. This solution uses depth-based view interpolation to create virtual views from a network of cameras located around the display screen. Using this method, users have the freedom to adjust their viewpoints to allow eye contact or to focus their attention on important regions. To improve the illusion of being in a common meeting room, we propose a new image matting algorithm to extract a participant from the background that can deal with hair and small details. This is essential as any small imperfections in the matte will destroy the illusion of being in a same virtual meeting room. In the thesis, we also explore how to overcome the uneven illumination found in tele-presence rooms. We present solutions to the illumination invariant stereo matching problem to create better disparity maps. Taking the advantage of the parallel structure of local stereo matching, the GPU implementation of the proposed solution can run in real time. Intensive experiments demonstrate the effectiveness and efficiency. In general, our main goal in this thesis is to develop core technologies that will eventually be used in future tele-presence systems.
Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
Citation for previous publication
Xiaozhou Zhou and Pierre Boulanger, New Stereo Matching Algorithm Using Radial Basis Function. In the Proceedings of Pacific-Rim Conference on Multimedia (PCM), pp.68-79, 2012.Xiaozhou Zhou and Pierre Boulanger, Illumination Stereo Matching based on Relative Gradients. In the Proceedings of International Conference on Image Processing (ICIP), pp. 2989-2992, 2012.Xiaozhou Zhou and Pierre Boulanger, A fast Hierarchical Radiometric Invariant Stereo Matching Algorithm. In the Proceedings of the International Conference on Information Science, Signal Processing and their Applications (ISSPA), pp. 383-388, 2012.Xiaozhou Zhou and Pierre Boulanger, Image Matting based on Mutual Information. In the Proceedings of IEEE Visual Communications and Image Processing (VCIP), pp.1-4, 2011.

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