AN ANALYSIS OF IMAGES BEFORE COMPRESSION IN PNG FORMAT
DOI:
https://doi.org/10.47839/ijc.9.2.712Keywords:
lossless images compression, LZ77 diving strategy, PNG files graphic format.Abstract
An influence of predictor’s different variants and their combination on PNG image compression is examined in this article. Fragments in C programming language for estimation of pixel lines entropy before and after application of context-dependent algorithm have been presented. A method for image analysis before the compression through breakdown of pixel lines with close entropy values into minimum blocks is offered. The method is based on the choice of an effective compression variant from five possible ones for every minimum block using dynamic programming and on the combination of contiguous minimum blocks in the homogeneous blocks of lines and on adjustment of their code parameters. It is experimentally showed that the images analysis, for example, allows to decrease the continuous tone images compression aspect of Kodak True Color PNG format image set on the average up to 12,37 bpp.References
T. Boutell et all. PNG Specification. Version 1.0, PNG Development Group, October 1996.
L. Peter Deutsch. DEFLATE Compressed Data Format Specification. Version 1.3, RFC 1951, 1996.
J. Ziv., A. Lempel. A universal algorithm for sequential data compression, IEEE Transactions on Information Theory, May 1977, vol. 23, no. 3, pp. 337–343.
D. Huffman. A method for the construction of minimum-redundancy codes, Proceedings of the I.R.E., September 1952, vol. 40, no. 9, pp. 1098–1101.
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Published
2010-12-20
How to Cite
Shport’ko, A. (2010). AN ANALYSIS OF IMAGES BEFORE COMPRESSION IN PNG FORMAT. International Journal of Computing, 9(2), 192-204. https://doi.org/10.47839/ijc.9.2.712
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