Patent US 7,526,141

The invention provides an image processing apparatus and an image processing method. An area to which image data belongs is discriminated, and a correction coefficient to be used for correction of a pixel value of the image data is produced based on a result of the discrimination. Then, the pixel value of the image data is corrected with the correction coefficient. The relationship in magnitude among pixel values in the same area is maintained because the same coefficient is used, but pixel values which belong to different areas can be varied or even reversed. This allows the gradation of an entire image to be corrected while preventing partial deterioration of the contrast.