A gamut-mapping algorithm with separate skin and non-skin color preference controls for wide-color-gamut TV

Recently emerging wide-color-gamut (WCG) TVs face two challenges. Viewers welcome the increase in color saturation of WCG TVs, but do not welcome unnatural skin color rendering due to the stretching of the narrower color gamut (such as the color gamut defined in sRGB/ITU-R BT.709/601). In this paper, we propose a color gamut mapping algorithm (GMA square to address the problem. The proposed GMA consists of two sub-GMAs: the first sub-GMA is focused on correctly rendering skin colors, and the second sub-GMA is on rendering no- skin colors. In order to allow viewers to independently adjust skin and non-skin colors according to their preference, the skin colors rendered by the first sub-GMA and the non-skin colors rendered by the second sub-GMA go through two seperate viewer preference adjustment modules. Then the mapped and viewer-adjusted skin and non-skin colors are blended according to skin scores, which are scalars between 0 and 1. A skin score is assigned to a color to describe its likelihood to be a skin color and is obtained by extensive training on sample sets. Skin scores of an image are filtered by a linear lowpass filter to prevent generating artifacts.