Fast fractal image coding algorithm based on ratio-of-horizontal-and-vertical-variances
Sun An · Journal of Hefei University of Technology · 2008
In view of the slow speed of fractal image encoding,a fast fractal image coding algorithm is proposed which reduces the number of self-symmetrical transforms from 8 to 4 according to the ratio-of-horizontaland-vertical-variances(RHVV) of the image blocks and restricts the codebook blocks to a relatively small sized window for each range block according to its RHVV,thus accelerating the encoding process.The experiment results indicate that: i) compared with the conventional algorithm the proposed one achieves remarkable performance in terms of speedup ratio with an insignificant decrease of Peak Signal Noise Ratio(PSNR) and compression ratio;ii) compared with the variance based on accelerating algorithm and using appropriate sized window,the proposed one gains a speedup ratio of around 2 with better performance of PSNR and compression ratio.