Color image gamut-mapping system with chroma enhancement at human- insensitive spatial frequencies

摘要

A method and system for gamut-mapping color images from device- independent form to device-dependent gamut in a Cartesian color space. Digital images are mapped to any device-dependent gamut in a manner that minimizes the human visual response both to the luminance and the chrominance changes necessary to force out-of-gamut pixels into the specified device-dependent gamut. A "neighborhood gamut mapping" technique considers the subjective visual effects of nearby pixels on the mapping of each pixel. Image luminance is biased toward the luminance in the device-dependent gamut at which the greatest chromamagnitude is available for a fixed hue angle. The chrominance of the mapped image is thereby imperceptibly adjusted to compensate for the human visual effects of luminance changes. Spatial filtering exploits the differing spatial frequency regions of insensitive human visual response to both luminance and chrominance changes.