Fractal Coding Based on Krawtchouk Moments and Adaptive Threshold Quadtree
Guo Jian-jun · Signal Processing · 2009
Long coding time is the main problem in fractal image compression at present,and the fixed match threshold between range blocks and domain blocks direcdy decides the image compression efficiency.In this paper,the Krawtchouk moments are firstly used to fractal coding based on adaptive threshold,the fractal coding method based on krawtchouk moments and adaptive threshold quadtree is proposed.12 moment invariants of the image blocks are calculated,and then these moment invariants are used as the eigenvector. The eigenvectors of Range blocks and those of Domain blocks are matched instead of grey value matrices.Experimental results are given and compared with the results of fractal image compression method based on adaptive threshold IFS.The results show that the scheme can shorten encoding time significandy,and the quality of the decoded image can also be improved.