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Proceedings Paper

Simple way to improve perceived quality of motion-compensated prediction images
Author(s): Albert A. Deknuydt; Stefaan Desmet; Luc Van Eycken; Andre J. Oosterlinck
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Paper Abstract

Almost all current video codecs are of the hybrid type and thus use motion compensated prediction. The motion vectors are assigned to rectangular blocks rather than pixels, because vector search algorithms are rather calculation intensive and because transmitting vectors for all pixels requires a substantial bit rate all by itself. However, if we see the motion vectors we are willing to transmit as a sampling of an underlying motion vector field, it is obvious that we can reconstruct this underlying field better than by simply using the zeroth order approximation (block-wise constant assumption), which is generally taken. In this paper, a simple alternative for this block-wide constant assumption is made. Transmitted vectors are seen as samples of a rather smooth realistic motion field. This assumes a more intelligent motion vector scheme than plain MAD. Vectors used for non sampling points are calculated by interpolation with vectors of neighboring blocks. Interpolation is done as that the transition between block boundaries is made as continuous as possible. This is achieved by a simple second order surface matching. To prove the validity of the scheme, several simulations were done. First, the perceived visual quality of the motion compensated prediction was evaluated. The scheme results in visually more acceptable predicted images, as their characteristic block appearance is greatly reduced. Secondly, the signal to noise ratio of the prediction was compared. Differences with the standard scheme are relatively small, and in either direction. Finally, a complete codec was tested with both predictions schemes.

Paper Details

Date Published: 17 April 1995
PDF: 7 pages
Proc. SPIE 2419, Digital Video Compression: Algorithms and Technologies 1995, (17 April 1995); doi: 10.1117/12.206361
Show Author Affiliations
Albert A. Deknuydt, Katholieke Univ. Leuven (Belgium)
Stefaan Desmet, Katholieke Univ. Leuven (Belgium)
Luc Van Eycken, Katholieke Univ. Leuven (Belgium)
Andre J. Oosterlinck, Katholieke Univ. Leuven (Belgium)

Published in SPIE Proceedings Vol. 2419:
Digital Video Compression: Algorithms and Technologies 1995
Arturo A. Rodriguez; Robert J. Safranek; Edward J. Delp, Editor(s)

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