Edge detection is one of the basic pre processing methods in digital image processing and computer vision. It is one of the most important algorithms making the processing going further. Edge detection is essentially a problem of color difference computing. Although edge detection has been explored deeply in gray image

it is still a difficult problem in color image for its trouble to define the color difference including not only value

but also direction. In this paper

a new color edge detection algorithm is proposed. This algorithm is based on Human Vision System (HVS) separating the chroma and intensity information of RGB color to emphasize the more important one. Inspired by this important property of HVS

the intensity difference and chroma difference are computed respectively

and then the weighted mean over these two differences is taken as the final color difference. This algorithm solves some problems produced by the existing algorithms and is proved to be a practical and effective color edge detection algorithm.