A technique for improving quality of an image displayed on a display apparatus by correcting the image has been proposed. For example, examples of a technique for increasing the contrast of an image include a gradation correction technique for correcting the gradation of luminance values set for pixels. Japanese Laid-open Patent Publication Nos. 2008-175880 and 2009-17229 disclose such a gradation correction technique. For example, in the gradation correction, the histogram of luminance values of pixels included in a display target image is generated and a region including a certain ratio of pixels in descending order of their luminance values is set as a cut-off region. This cut-off region is, for example, a region including pixels corresponding to 0.5% of all pixels. In the related art, a highlight value that is the minimum value among the luminance values included in the cut-off region is changed to the maximum luminance value in the histogram. Thus, in the related art, the gradation of luminance values set for pixels is corrected. The gradation correction is also referred to as dynamic range correction.
There is also a technique employed in a display apparatus for displaying an image with a backlight. The technique reduces power consumption while maintaining image quality by increasing the luminance value of an image with the above-described gradation correction technique and reducing the amount of light of the backlight.
USPTO Backgrounds
USPTO Backgrounds