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Proceedings Paper

Invisible modification of the palette color image enhancing lossless compression
Author(s): Jaroslav Fojtik; Vaclav Hlavac
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Paper Abstract

Our contribution relates to lossless compression of pseudo color images (images with a palette). The proposed method is a preprocessing step preceding actual compression. During preprocessing indices in the palette are semioptimally permuted. For actual image compression, our own nonlinear predictor based method is used but the proposed invisible palette modification is relevant to most of other compression techniques too. Experiments with numerous images show that indices reordering in the palette yields data savings from 10 to 50% for typical images. We suggest a preprocessing phase that (a) analyzes statistics of the adjacency relations of index values, (b) performs optimization, and (c) permutes indices to palette to achieve more smooth image. The smoother image causes that the lossless image compression methods yield less output data. The task to optimally permute indices is a NP complete combinatorial optimization. Instead of checking all possibilities, we propose a reasonable initial guess and a fast suboptimal hill climbing optimization.

Paper Details

Date Published: 7 September 1998
PDF: 11 pages
Proc. SPIE 3409, Electronic Imaging: Processing, Printing, and Publishing in Color, (7 September 1998); doi: 10.1117/12.324115
Show Author Affiliations
Jaroslav Fojtik, Czech Technical Univ. (Czech Republic)
Vaclav Hlavac, Czech Technical Univ. (Czech Republic)


Published in SPIE Proceedings Vol. 3409:
Electronic Imaging: Processing, Printing, and Publishing in Color
Jan Bares, Editor(s)

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