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Proceedings Paper

Aliasing reduction via frequency roll-off for scalable image/video coding
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Paper Abstract

The extracted low resolution video from a motion compensated 3-D subband/wavelet scalable video coder is unnecessarily sharp and sometimes contains significant aliasing, compared to that by the MPEG4 lowpass filter. In this paper, we propose a content adaptive method for aliasing reduction in subband/wavelet scalable video coding. We try to make the low resolution frame (LL subband) visually similar to that of the MPEG4 decimation filter through frequency roll-off. Scaling of the subbands is introduced to make the variances of the subbands comparable in these two cases. Thanks to the embedded properties of the EZBC coder, we can achieve the needed scaling of energies in each subband by sub-bitplane shift in the extractor and coefficient scaling in the decoder. An analysis is presented for the relationship between sub-bitplane shift and scaling, which shows that our selected sub-bitplane shift works well for high to medium bitrates. Two different energy-matching structures, i.e. a dyadic decomposition and non-dyadic decomposition, are proposed. The first dyadic method has low complexity but low accuracy for energy matching, while the second non-dyadic method is more accurate for energy matching but has higher analysis/synthesis complexity. The first scheme introduces no PSNR loss for full resolution video, while the second one introduces a slight PSNR loss for full resolution, due to our omission of interband context modeling in this case. Both methods offer substantial PSNR gain for lower spatial resolution, as well as substantial reduction in visible aliasing.

Paper Details

Date Published: 19 January 2006
PDF: 12 pages
Proc. SPIE 6077, Visual Communications and Image Processing 2006, 60771E (19 January 2006); doi: 10.1117/12.648439
Show Author Affiliations
Yongjun Wu, Rensselaer Polytechnic Institute (United States)
John W. Woods, Rensselaer Polytechnic Institute (United States)

Published in SPIE Proceedings Vol. 6077:
Visual Communications and Image Processing 2006
John G. Apostolopoulos; Amir Said, Editor(s)

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