Gradient operators in color edge detection were classified as classical edge detection operators for gray image and vector operators. Vector method which was based on vector operators is easy to understand. It has relatively small amount of calculation and detects fine edge. Four kinds of representative vector operators were researched: VR (Vector rank operator), MVD (Minimum vector dispersion), CMG (Color Morphological Gradient operator) and RCMG (Robust color morphological gradient operator). Simulation results using MATLAB certified that the operators are all effective for noiseless color edge detection and RCMG operator has a better anti-noise ability. http://www.sjie.org/paperInfo.aspx?ID=469
