Gamut clipping and mapping based on the coloroid system

The paper presents novel techniques based on the Coloroid color system which hitherto has not been applied to gamut mapping. The introduced methods described are hue preserving and use three gravity centers in a hue-dependent way. Two of the gravity centers are shifted toward the direction of 'negative saturation', and can be used for regions of bright and dark colors, while a third gravity center is used for saturated colors. After a short survey of gamut mapping an introduction to the Coloroid describes concisely its features and formulas. Then a simple color clipping rule is presented applicable to any rendering applications. A gamut mapping method will be defined mapping from a generic input image to an RGB display. Other variations of the method describe RGB-CYMK transformation and also cross-media mapping for known input and output gamut boundaries. The introduced methods apply hue and chroma dependent lightness compression. They can be applied in realistic computer graphics and digital photography as well as in printing technologies. They are straightforward to implement and have low computational costs.