Color image sharpening based on nonlinear reaction-diffusion

Previously we have presented a selective sharpening method for monochrome images. Our method is based on the simultaneous nonlinear reaction-diffusion time-evolution equipped with a nonlinear diffusion term, a reaction term and an overshooting term, and can sharpen degraded edges blurred by several causes without increasing the visibility of random noise. This paper extends our method to selective sharpening of color images. As to the how to extend it, we take into accounts two variations about the treatment of three color components and the selection of the color space. By experiments, we quantitatively evaluate performance of these variations. The best performance is achieved by the collective treatment of color components based on the simultaneous full-nonlinear reaction-diffusion time-evolution, and blurred color edges are sharpened selectively much better than by the existing methods such as the adaptive peaking method.