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Proceedings Paper

Spatial and frequency decomposition for image compression
Author(s): Wei-Lien Hsu; Haluk Derin
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Paper Abstract

This paper presents the design of an improved image compression algorithm based on an optimal spatial and frequency decomposition of images. The use of spatially varying wavelet packets for a generalized wavelet decomposition of images was recently introduced by Asai, Ramchandram and Vetterli. They use a `double tree' algorithm to obtain the optimal set of bases for a given image, through a joint optimization with respect to frequency decomposition by a wavelet packet and spatial decomposition based on a quad-tree structure. In this paper, we present a `double-tree' frequency and spatial decomposition algorithm that extends the existing algorithm in three areas. First, instead of the quad-tree structure, our algorithm uses a more flexible merging scheme for the spatial decomposition of the image. Second, instead of a scalar quantizer, we use a pyramidal lattice vector quantizer to represent each subband of each wavelet packet, which improves the coding efficiency of the representation. Both of these extensions yield an improved rate-distortion (R-D) performance. Finally, our algorithm uses a scheme that gives a good initial value for the slope of the R-D curve, reducing the total computations needed to obtain the optimum decompositions.

Paper Details

Date Published: 27 April 1995
PDF: 12 pages
Proc. SPIE 2431, Medical Imaging 1995: Image Display, (27 April 1995); doi: 10.1117/12.207660
Show Author Affiliations
Wei-Lien Hsu, Univ. of Massachusetts/Amherst (United States)
Haluk Derin, Univ. of Massachusetts/Amherst (United States)

Published in SPIE Proceedings Vol. 2431:
Medical Imaging 1995: Image Display
Yongmin Kim, Editor(s)

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