Fractal Image Compression by YIQ Color Space

In fractal compression the image to be encoded is partitioned into blocks called (ranges). Each range is coded by reference to some other part of the image called (domain) and by some affine transformation parameters. The number of ranges plays an important role in the compression ratio, encoding time and reconstructed image quality. In this paper, the fractal compression technique proposed by Jacquin is investigated for 24 bits/pixel color image. The data of the color component (R,G,B) are transformed to (YIQ) color space, to take the advantage of the existing spectral correlation to gain more compression. Also the low spatial resolution of the human vision systems to the chromatic components (I,Q) was utilized to increase the compression ratio without making significant subjective distortion. The test results show that PSNR (31.05) dB with CR (8.73) and encoding time (57.55) sec for Lena image (256x256) pixel.