Park Yong Ki, Park Chul Woo, Kim Doo Young

The Transactions of the Korea Information Processing Society (1994 ~ 2000), Vol. 4, No. 12, pp. 3185-3199, Dec. 1997
10.3745/KIPSTE.1997.4.12.3185,   PDF Download:

Abstract

This paper suggests techniques to reduce coding time which is a problem in traditional compression and improve fidelity of reconstructed images by determining fractal coefficient through adaptive selection of block approximation formula. First, to reduce coding time, we construct a linear list of domain blocks of which characteristics is given by their luminance and variance and then we control block searching time according to the first permissible threshold value. Next, when employing three-level block partition, if a range block of minimum partition level cannot find a domain block which has a satisfying approximation error, we choose new approximation coefficients using a non-linear approximation of luminance term. This boosts the fidelity. Our experiment employing the above methods shows enhancement in the coding time more than two times over traditional coding methods and shows improvement in PSNR value by about 1-3dB at the same compression rate.

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