| 摘要 |
A method and apparatus for color image processing using gamut mapping reduces halo artifacts by correcting terms in a gamut mapping algorithm. The color image may be represented by f, the in gamut image by g, the target gamut by C, and the gamut constraint by c. The method for reducing halo artifacts includes two correction steps. First a color distance term L>2< in the gamut mapping algorithm is corrected (110). Second, a distance measure of an image gradient in the gamut mapping algorithm is corrected (115). The first correcting step comprises computing a function u = project>C<(f). The second correcting step comprises computing a scaled down function for f. Next, a function g(x,y) is determined (125) that minimizes a functional comprising the color distance term and the image gradient term. The solution may be determined by iteration (130, 135, 140, 145) using a gradient descent operation by first initializing g>0< = project>C<(f), and then performing one or more iteration steps to compute g(x,y).
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