A Multi-Resolution, Full-Colour Spatial Gamut Mapping Algorithm

A multi–resolution, full–colour spatial gamut mapping algorithm (GMA) is proposed in this paper. Its aim is to maintain as much of an original image’s overall, and in particular spatial, information as possible within the limits of a reproduction medium’s gamut. First, the original image is decomposed into different spatial frequency bands. Second, lightness compression and initial gamut mapping are applied to the lowest frequency band image. Third, the next higher frequency band is added to the gamut mapped image and the result is processed by subsequent gamut mapping transformations. The third step is repeated until the highest frequency band is reached. The effect of this algorithm is that intra–image differences in the original image are well maintained in the gamut mapped reproduction. A psychophysical experiment is then described whose results show that this algorithm is in the pair of most accurate GMAs and can outperform all other algorithms tested here for images which are less accurately reproduced by all GMAs.