This paper describes color gamut mapping technique as an optimization problem for finding an image which is perceptually closest to the original one among the images which only contain reproducible colors for the destination device. Perceptual difference between images is defined as
a color difference of band-pass-filtered images rather than simple summation of Δ
Shigeki Nakauchi, Masahiro Imamura, Shiro Usui, "Color Gamut Mapping by Optimizing Perceptual Image Quality" in Proc. IS&T 4th Color and Imaging Conf., 1996, pp 63 - 66, https://doi.org/10.2352/CIC.1996.4.1.art00018