標題: Perceptual dithering for octave subband image coding
作者: Wang, CN
Liu, CM
Chiang, TH
資訊科學與工程研究所
Institute of Computer Science and Engineering
關鍵字: image coding;perceptual image coding;perceptual dithering;perceptual dithering coding;perceptual correlation;interband correlation;wavelet transform;octave decomposition;octave subband coding;MPEG-4 visual texture coding (VTC)
公開日期: 1-Jun-2004
摘要: Octave subband coding has been used as an efficient image coding approach for various well-known standards such as MPEG-4 and JPEG-2000. Although the sub-images in the octave subband representation have low statistical correlation, the visual similarity among the sub-images indicates that there exists some unexploited perceptual redundancy between sibling bands in addition to the parent-child redundancy. In this paper, we show that the original image can be perceptually dithered to form a visually equivalent image with increased interband correlation that can be used to achieve more compression. To remove the redundancy among the sibling subbands of an image, we provide a novel perceptual dithering approach that is based on entropy reduction technique with perceptual model. The theoretical basis for the entropy reduction is proven by a theorem for Gaussian distributed signals. The use of our dithering technique is demonstrated for an MPEG-4 compliant encoder with improved coding efficiency using MPEG-4 Visual Texture Coding (VTC) based on zerotree entropy coding. Our results show that there exists a perceptual interband redundancy even though the original interband correlation is small. For a perceptually transparent image quality, our approach can achieve bit savings over MPEG-4 VTC by 11-30%, while maintaining compatibility with the MPEG-4 standards. (C) 2003 Elsevier Inc. All rights reserved.
URI: http://dx.doi.org/10.1016/j.jvcir.2003.07.003
http://hdl.handle.net/11536/26729
ISSN: 1047-3203
DOI: 10.1016/j.jvcir.2003.07.003
期刊: JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION
Volume: 15
Issue: 2
起始頁: 163
結束頁: 184
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