VQ-encoding of luminance parameters in fractal coding schemes

This paper is concerned with the efficient storage of the luminance parameters in a fractal code by means of vector quantization (VQ). For a given image block (range) the collage error as a function of the luminance parameters is a quadratic function with ellipsoid contour lines. We demonstrate how these functions should be used in an optimal codebook design algorithm leading to a non-standard VQ-scheme. In addition we present results and an evaluation of this approach. The analysis of the quadratic error functions also provides guidance for optimal scalar quantization.