| US 7,602,537 B2 | ||
| Gamut mapping with primary color rotation | ||
| Sharon A. Henley, Mountain View, Calif. (US); and Rocklin J. Sloan, San Jose, Calif. (US) | ||
| Assigned to Canon Kabushiki Kaisha, Tokyo (Japan) | ||
| Filed on May 06, 2004, as Appl. No. 10/840,564. | ||
| Prior Publication US 2005/0248784 A1, Nov. 10, 2005 | ||
| Int. Cl. G03F 3/08 (2006.01); G06F 15/00 (2006.01) | ||
| U.S. Cl. 358—520 [358/523; 358/1.9] | 9 Claims |
| 1. A method, implemented in a computer, of performing gamut-mapping from a source device to a destination device in a perceptually
linear color space, comprising:
a processor of the computer performing the steps of:
obtaining a source image in the perceptually linear color space;
determining tristimulus values for the source image and converting the tristimulus values to device-independent color appearance
space values;
obtaining a source hue wheel for the source device and a destination hue wheel for the destination device, each of the source
hue wheel and the destination hue wheel respectively comprising known hue angles for each of primary (RGB) and secondary (CMY)
color components of their respective source and destination color gamuts;
determining a source hue angle of the source image in the source hue wheel, and determining a source relative position of
the source image in the source hue wheel between a primary color component and a secondary color component nearest to the
source hue angle;
determining, in the destination hue wheel, a corresponding relative position between the primary color component and the secondary
color component corresponding to the primary color component and the secondary color component in the source hue wheel nearest
to the source image, the determined relative position in the destination hue wheel resulting in a destination hue angle;
obtaining a source hue leaf from the source color gamut at the determined source hue angle for the source image, and obtaining
a destination hue leaf from the destination color gamut at the destination hue angle;
performing a mapping process between the source hue leaf and the destination hue leaf to fit the source hue leaf within the
destination hue leaf; and
convening results of the mapping process from device-independent color appearance space values to tristimulus values, and
converting the converted tristimulus values to a perceptually linear color space of the destination device.
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