Research Of Gamut Expansion Mapping Based On Laser TV

Different media or devices have different color display ability and color gamuts. To render colors accurately on different media or devices, there needs to be a gamut mapping process. Since it has been proposed, gamut mapping was always being compression and clip mapping from display gamut to printer gamut due to the needs of application; gamut expansion has rarely been concerned about. However, wide gamut displays that using more-saturated primaries, like laser TV, emerged several years ago. And this brings great significance to the research of gamut expansion mapping. Because theses systems have different primaries with the gamut standards and thus have wider gamuts, gamut expansion mapping must be carried out to firstly correct the color display error and then exert the color display advantage of wide gamut displays.This paper mainly focuses on the gamut expansion research of standard gamut, e.g. the sRGB, to the gamut of laser display, and proposes two gamut expansion methods. Traditional gamut mapping methods, the status quo of gamut mapping, standard gamuts and color spaces that are used in the gamut mapping process are firstly introduced. Then device characterization, i.e. the conversion of device RGB to CIEXYZ values is discussed. Then CIELUV 3D linear gamut expansion method is proposed based on the study of hue linearity of color spaces. Gamut expansion experiments from sRGB gamut to gamut of laser TV are carried out. The results show that the method has rather good hue preserving performance and could yield natural images. Since the gamut boundary calculation of CIELUV 3D linear expansion method has huge computational cost, another gamut expansion method that has simple gamut boundary descriptor is proposed. The method is mainly changing the saturation according to the location of the input color in Y-xy color space. Then the method was rectified and revised based on experiments. Color colorfulness index was introduced to evaluate the gamut expansion results. Lastly, three dimensional linear interpolation methods are studied because the real time realization of gamut expansion must adopts 3-D look up table and interpolation structure. Cubic interpolation, prism interpolation and tetrahedron inter-polation methods are tested on their interpolation accuracy and time costs. It shows that cubic interpolation has better interpolation accuracy and less time cost than prism interpolation and tetrahedron interpolation.