| 摘要 |
PROBLEM TO BE SOLVED: To provide a chroma correction unit which corrects only the chroma appropriately for an appropriately corrected luminance without changing the hue through a simple arrangement. SOLUTION: The chroma correction circuit comprises a matrix operating circuit 1, a reference signal calculating circuit 2, and a gain calculating circuit 3. The matrix operating circuit 1 operates the input luminance signal of a target pixel, and an input color difference signal on a first plane defined such that the axes of respective orientation vectors of tristimulus values of a color image signal projected about a luminance axis intersect at 120°. The reference signal calculating circuit 2 calculates a luminance signal value having a maximum distance from the luminance axis in a color reproduction area which can be taken by the tristimulus values on a second plane traversing the first plane including a point corresponding to the target pixel on the first plane and the luminance axis, and outputs the luminance signal value as a reference signal. The gain calculating circuit 3 compares the input luminance signal and the output luminance signal with the reference signal and calculates a gain signal being multiplied in order to correct the input color difference signal depending on the comparison results. COPYRIGHT: (C)2004,JPO&NCIPI
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