Gray Level of FIC using Zero-Mean Method

In this work, a fractal image compression (FIC) based on zero-mean block matching method is adopted. In this method the mean of the range blocks is used instead of traditional offset parameter. The parameter ( ) has a smaller dynamic range [0,255] than the (o) parameter [-255,511] which using in traditional method. This may cause large errors in some image regions (or points) especially those which belong to high contrast area. Replace this factors also reduces and simplifies the computations of the affine parameters during the encoding process. The test results conducted on 24 bits/pixel gray Cat image indicated that the encoding time (7.47) sec, compression ratio (5.63) ,PSNR (35.16) .