LUMINANCE CONVERSION CURVE CREATION DEVICE AND METHOD, AND LUMINANCE CONVERSION CURVE CREATION PROGRAM

摘要

PROBLEM TO BE SOLVED: To prevent color information of a specific image after luminance conversion from largely deviating from that before the conversion.SOLUTION: Upper limit saturation and lower limit saturation of a face image portion are calculated based on a target average luminance value (step 31A). Then, the average RGB values of the face image portion and the average RGB values after luminance conversion of the face image portion using a standard luminance conversion function are calculated (steps 32 and 33). When predicted saturation calculated from the average RGB values of the face image portion after the luminance conversion is out of an allowable range (between the upper limit saturation and the lower limit saturation) (step 35A), the luminance conversion function is modified so that the predicted saturation falls within the allowable range (steps 37 and 39).