| 摘要 |
PROBLEM TO BE SOLVED: To adjust the chroma of an image, without lowering image quality. SOLUTION: A relationship between a phase angle and a weighting factorα1 is decided, in such a way that the weighting factorα1 becomes 0 or a value close to 0 in a prescribed range around a phase angle H* nearly equal 45 deg. (skin color) on an output image, as shown in (A). A relationship between a normalized chroma and a weighting factorα2 is decided, in such a way that the weighting factorα2 becomes 0 or a value close to 0, in a range in which the normalized chroma is close to 0 and in a range close to the outermost skin on the output image, as shown in (B). The relationship between the normalized chroma and a weighting factorα3 is decided, in such a way that the weighting factorα3 becomes 0 or a value close to 0, in a range in which a normalized lightness is close to 0 and in a range close to the maximum lightness on the output image, as shown in (C). A chroma adjustment amount by chroma adjustment data, which is set at a 3D-LUT for chroma adjustment, are decided by using the weighting factorsα1,α2,α3. The chroma adjustment data are set at the 3D-LUT for chroma adjustment, and chroma is adjusted.
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