<title>Three-dimensional gamut mapping using various color difference formulae and color spaces</title>

Abstract

Gamut mapping is a technique to transform out-of-gamut colors to the inside of the output device's gamut. It is essential to develop effective mapping algorithms to realize ''WYSIWYG'' color reproduction. In this paper, three-dimensional gamut mapping using various color difference formulae and color spaces are considered. Visual experiments were performed to evaluate which combination of color difference formula and color space for gamut mapping was most preferred for five images. The color difference formulae used in the experiments were DEab , DEuv , DE94 , DECMC , DEBFD , and DEwt . The color spaces used in the experiments were CIELAB, CIELUV, CIECAM97s, IPT, and NC-IIIC. A clipping method was used that maps all out-of-gamut colors to the surface of the gamut, and no change was made to colors inside the gamut. It was found that gamut mapping using DE94 , DECMC , and DEwt were effective in CIELAB color space. For mapping images containing a large por- tion of blue colors, DEBFD and DEuv were found to be more effective. DEab was least preferred for all images. With respect to color spaces, gamut mapping performed in the CIELUV color space was superior to any other color spaces for the blue region. We conclude that DE94 in CIELUV and DEBFD in CIELAB are the two most useful combinations of color difference formula and color space for gamut mapping, if we are to apply a single combination universally. © 1999 SPIE and IS&T. (S1017-9909(99)00304-9)