Analysis on the effect of tolerance criteria in fractal image compression

Fractal image compression (FIC) is achieved either by using iterated function systems (IFS) or by partitioned iterated function systems (PIFS). An image is coded as a set of contractive transformations in a complete metric space. The set of contractive transformations is guaranteed to produce an approximation to the original image. This paper deals with PIFS using quad-tree based encoding, applied on mammogram. In this paper FIC, using quad-tree partitioning is applied on Mammograms by varying the parameter, tolerance criterion T_max. The Compression ratios and the image quality factor PSNR are studied using the above method of fractal image compression. We observe that the compression ratio increases with the tolerance value and the quality of the image is not degraded because of the properties of fractal compression, which is indicated by the PSNR values.