Patent ID: 8090198
Filing Date: 2012-01-03
Classification: G06T,G09G,H04N

Abstract:
1. An image processing apparatus comprising: a maximum and minimum color information detector that detects maximum gradation levels of respective ones of a plurality of color signals constituting an input image signal or a value equivalent to the maximum gradation level and minimum gradation levels of respective ones of the plurality of the color signals constituting the input image signal or a value equivalent to the minimum gradation level as maximum and minimum color information of the input image signal; a maximum and minimum luminance information detector that detects a maximum gradation level, or a value equivalent to the maximum gradation level, of a luminance signal component of the input image signal and a minimum gradation level, or a value equivalent to the minimum gradation level, of the luminance signal component of the input image signal as maximum and minimum luminance information of the input image signal; a correction generator that sets a correction parameter according to the maximum and minimum color information and the maximum and minimum luminance information of the input image signal; and a gradation corrector that corrects a gradation scale of each color component of the input image signal according to the correction parameter; wherein, the maximum luminance signal gradation level or the value equivalent to the luminance signal maximum gradation level is denoted by YMAX, the minimum luminance signal gradation level of the value equivalent to the luminance signal minimum gradation level is denoted by YMIN, a color signal maximum gradation information value which is a largest value of the maximum gradation levels of the respective ones of the plurality of color signals is denoted by CMAX, a color signal minimum gradation information value which is a smallest value of the minimum gradation levels of the respective ones of the plurality of color signals is denoted by CMIN, a maximum value which a color signal component gradation level can assume is denoted by GMAX, a minimum value which a color signal component gradation level can assume is zero, and the correction parameter generator generates a post-gradation-correction target value YMAXt and a post-gradation-correction target value YMINt such that where α represents a margin of the post-gradation-correction target value CMINt of the color signal minimum gradation information value with respect to the minimum value which the color signal gradation level can assume, β represents a margin of the post-gradation-correction target value CMAXt of the color signal maximum gradation information value with respect to GMAX, and where the correction parameter generator determines the correction parameter based on YMAXt and YMINt.