An Efficient Fractal ImageCoding Method Using Interblock Correlation

An Efficient Fractal Image-Coding Method Using Interblock Correlation Search Source: IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY, VOL. 11, NO 1, JANUARY 2001, pp. 257 -261 Authors: Chou-Chen Wang and Chaur-Heh Hsieh Seapker: Hsien-Chu Wu Date: July 19, 2001

Outline Fractal image compression Fast fractal image compression using local variance Interblock correlation search scheme The proposed method Experimental results Conclusions

Fractal image encoding Self similarity of an image

Fractal image encoding Domain Block Range Block ．．．． Contractive affine Transform (1)Isometric (2)scale (3)Luminance Domain Pool (4)Position

Fast fractal image compression using local variance Domain Block Domain pool All domain blocks are sorted by the corresponding local variances in descending order Sorted domain pool

Fast fractal image compression using local variance Range Block (1)Calculate local variance (2)Find the closest domain block (3)Define the search window by using the percentage w% and find search window for the closest domain block Domain pool(sorted) w/2%

Interblock correlation search scheme D 3 D 4 2 3 4 D 2 1 D 1 The same image

The proposed method Select a range block Check if one of the candidate domain blocks is good enough N Y Record (1) search order code (2) luminance (3) scale Call fast compression method using local variance

Experimental results(1/4)

Experimental results(2/4)

Experimental results(3/4)

Experimental results(3/4)

Conclusions Take advantage of the correlation between range blocks Achieve significant reduction of computation time and bit rate with insignificant degradation of PSNR