An improved scheme for fractal image coding

The performance of the fractal image coding system is improved in our research. Comparing with our previous work and the original work accomplished by Jacquin, both the PSNR and the compression ratio are increased. Based on the local similarity of nature images, the search region of the domain blocks is confined within the neighborhood of the range block. The search region for child domain blocks are extended to get a better match process. On the other hand, testing all the possible 8 values of the contrast scaling and selecting the best one further improves the performance. The blocking effect due to the mean-coded range block is also reduced by using a post-processing technique. Here we achieve a 33.9 dB PSNR at the bit rate 0.45 bit/pixel, while our previous work and Jacquin´s scheme achieved 32.6 dB at 0.52 bit/pixel and 32 dB PSNR at 0.6 bit/pixel, respectively