QR-RLS algorithm for error diffusion of color images

Printing color images on color printers, and displaying them on computer monitors requires a significant reduction of physically distinct colors, which causes degradation in image quality. An efficient method to improve the display quality of a quantized image is error diffusion which works by distributing the previous quantization errors to neighboring pixels exploiting the eye´s averaging of colors in the neighborhood of the point of interest. This creates the illusion of more colors. A new error diffusion method is presented in which the adaptive recursive least squares (RLS) algorithm is used rather than the deterministic approaches in literature. To improve the performance, a diagonal scan is used in processing the image