Patent ID: 8649597

Claim:
An image processing apparatus, comprising: a histogram creation unit configured to create a histogram from an input image; a detection unit configured to detect from the histogram, as a gradation level of interest, a gradation level whose frequency is a peak value, wherein a variation width of frequencies in a predetermined range including the gradation level of interest is smaller than a predetermined width; a gradation correction parameter generation unit configured to generate a gradation correction parameter having an input-output gradation conversion characteristic that improves a gradation characteristic in a predetermined gradation range including the gradation level of interest compared to other gradation ranges on the bases of the detected result by the detection unit; and a correction unit configured to correct the gradation of the image using the gradation correction parameter generated by the gradation correction parameter generation unit, wherein the detection unit determines whether the variation width of frequencies in the predetermined range is smaller than the predetermined width or not based on (1) a frequency of a gradation level that is a target for which it is to be determined whether the gradation level is a gradation level of interest or not, and (2) a value obtained by multiplying a total of frequencies of a respective n number of gradation levels, where n is an integer of 1 or greater, at lower and higher sides of the gradation level that is the target, excluding the gradation level that is the target, by a predetermined value.