To extend the ability of dichromats to recognize the color difference, we propose a method to expand the color difference when observed by dichromats. We analyze the color between the neighboring pixels not in intensity space but chromaticity space and form a Poisson equation. In addition, we use the sigmoid function to weigh the edge of a color image. The color difference can be adequately tuned manually by the weight parameter so that the dichromats can obtain the image that they want where the visibility of the color is enhanced. |