Fractal coding of color images using the correlation between Y and C components

Abstract

This paper presents an efficient fractal coding scheme for color images and demonstrates its experimental results. The proposed fractal coding scheme utilizes the correlation between a luminance component (Y) and two color difference components (Cr and Cb) of an input color image. The Y, Cr and Cb components are first decomposed to low and high frequency sub-band images. Fractal block coding is performed only on the lowest frequency sub-band images of Y, Cr and Cb. The other high frequency sub-band images are encoded by vector quantization (VQ). In the fractal coding process for Y, each range block is encoded by a set of contractive affine transformations of its correspondent domain block. For Cr and Cb, on the other hand, only the range block average values are coded. The other fractal coded data of the correspondent range block of Y are applied also to Cr and Cb. The computer simulation experimental results show that the coded and decoded color images obtained by the proposed scheme give higher SNR values and better image qualities compared to the conventional fractal coding scheme and JPEG.