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An object-based system for stereoscopic videoconferencing with viewpoint adaptation

: Ohm, J.-R.; Izquierdo, E.

Ohta, N. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.; Technologiestiftung Innovationszentrum, Berlin:
Digital compression technologies and systems for video communications : 7-9 October 1996, Berlin, FRG
Bellingham/Wash.: SPIE, 1996 (SPIE Proceedings Series 2952)
ISBN: 0-8194-2356-4
Conference "Digital Compression Technologies and Systems for Video Communications" <1996, Berlin>
Fraunhofer HHI ()
feature extraction; image matching; interpolation; stereo image processing; telecommunication computing; teleconferencing; object-based system; stereoscopic videoconferencing; viewpoint adaptation; disparity estimation; hierarchical block matching algorithm; feature points; interpolation algorithm; real-time videoconferencing; telepresence illusion; hardware feasibility

This paper describes algorithms that were developed for a stereoscopic videoconferencing system with viewpoint adaptation. The system identifies foreground and background regions, and applies disparity estimation to the foreground object, namely the person sitting in front of a stereoscopic camera system with rather large baseline. A hierarchical block matching algorithm is employed for this purpose, which takes into account the position of high-variance feature points and the object background border positions. Using the disparity estimator's output, it is possible to generate arbitrary intermediate views from the left- and right-view images. We have developed an object-based interpolation algorithm, which produces high-quality results. It takes into account the fact that a person's face has a more or less convex surface. Interpolation weights are derived both from the position of the intermediate view, and from the position of a specific point within the face. The algorithms have been designed for a real-time videoconferencing system with telepresence illusion. Therefore, an important aspect during development was the constraint of hardware feasibility, while sufficient quality of the intermediate view images had still to be retained.