A Hybrid Image Compression Algorithm Based on Fractal and Wavelet Transforms

Abstract

The self-similarity feature of fractal compression makes it work based on iterated function system. Discrete Wavelet transform of an image provides a set of wavelet coefficients which represent the image at multiresolution. There exists a connection between wavelet transform and fractal compression because the self-similarity existed in wavelet transform could be exploited by fractal theory. The purpose of this paper is to propose a hybrid image coder based on fractal coding and wavelet coding schemes. The similarity among different subbands of the same orientation in a wavelet decomposition of the image is exploited for block prediction in fractal coding scheme. The optimal sizes of range blocks for each subband have been evaluated by experiments. The evaluated data is used in the hybrid image coding scheme. The experimental results show that PSNR and CR are 29.2, 19.8 respectively in our method. the performance of our hybrid image coder is superior to that obtained from baseline fractal image coder for both visual quality and mean square error.