Color image compression using fast VQ with DCT based block indexing method
ICIAR'11 Proceedings of the 8th international conference on Image analysis and recognition - Volume Part II
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In this paper, speeding-up fractal color image compression technique based on zero-mean method by adding symmetry predictor to reduce the number of isometric trails from 8 to one trail. The first order centralized moments are used to index each domain and range blocks onto one of eight possible isometric states. At each range domain the indices of both domain and range blocks are passed through the predictor, then the predictor outputs the index of the required isometric transform (that needed to be applied on the domain block) to get the best possible match between the domain and range blocks. Also the indexes of range mean and scale have been coded using DPCM followed by shift coding. The test results led to encoding time (4.81) sec, PSNR (33.28) and compression ratio (10.34). These results show that reduction in the encoding time about 7 times in comparison with classical method but the CR and PSNR was nearly preserved.