About the Influence of the Brightness and Contrast Transform Accuracy on the Image Quality in Fractal Compression

Brightness and contrast transform of domains is an essential part of fractal image compression algorithm. Traditionally well-known fixed number of bits are used for storing of brightness and contrast transform coefficients chosen from fixed ranges. At the same time, these ranges and accuracy of transform coefficients severely affects the distortions of the reconstructed image. In this paper, we investigate the influence of the ranges and the storing accuracy of the brightness and contrast transform coefficients for domains on the quality of the reconstructed image in fractal image compression. The research has been shown that appropriate adjusting of the coefficients ranges before significant decrease of the number of bits for its storing allow to achieve rather small degradation in reconstructed image (PSNR loss ~ 0.1 – 0.3 dB).