Patent ID: 7791652

Claim:
An image processing apparatus comprising: contrast area detection means for detecting a partial area from among partial areas in an input image signal as a contrast area, the input image signal being formed by a plurality of pixels, the contrast area being a partial area in which contrast of an input luminance indicative of a luminance of the input image signal is greater than a predetermined value, wherein the contrast area detection means includes: local contrast calculation means for calculating the contrast of the input luminance of each of the partial areas as a local contrast, and threshold decision means for determining whether the local contrast of the input luminance of each of the partial areas is greater than a predetermined threshold, the threshold decision means determining that if the local contrast is greater than the predetermined threshold, the partial area corresponds to the contrast area; luminance distribution means for distributing the input luminance in the contrast area into a bright-side luminance corresponding to a bright side of the input luminance and a dark-side luminance corresponding to a dark side of the input luminance; and boundary luminance value generation means for generating a boundary luminance value between the bright-side luminance and the dark-side luminance on the basis of the distributions of the bright-side luminance and the dark-side luminance, wherein the contrast calculation means calculates as the local contrast an absolute value of a local first order derivative of the input luminance of each of the partial areas.