Color removal method based on signed color distance and nonlinear projection

In the typical photo re-touching software, in order to convert a color image into a monochrome one, only luminance components of the color image are extracted, and are used to represent the monochrome image. This luminance extraction is useful and enough for obtaining a monochrome image in most cases. However, saliencies of the image included only in the chrominance components are not preserved at all. In this study, we propose a new color removal method that takes difference of the chrominance into account in addition to luminance of an image. The effectiveness of the proposed method is verified by applying it to some images.