A Gamut-Mapping Framework for Color-Accurate Reproduction of HDR Images

An integrated gamut and tone-management framework for color-accurate reproduction of high dynamic range (HDR) images can prevent hue and luminance shifts while taking gamut boundaries into consideration. The framework incorporates tone mapping, chroma correction, and gamut management to process an HDR image for a given output gamut. The input to the method is an HDR image given in linear XYZ coordinates. First, the image's luminance channel, denoted I(L), is compressed using any existing TMO. The resulting image's chroma channel I(C) is then corrected with the chroma compression algorithm to correct for unwanted saturation resulting from the tone-mapping process. Finally, image chroma and luminance values I(C, L) are processed in a gamut-management step to ensure that all pixels fit within the target gamut boundaries, denoted G(C, L), while minimizing appearance changes in the image. The solution also allows for flexibility in the choice of compressive function: different functions can lead to different image appearances. Despite the different tone-mapping styles, the chroma correction leads to a consistent treatment of colors in the images.