Image processing device and method to correct brightness signal of an input image

摘要

A region determination circuit (60) determines whether or not each of the pixels in an image is within a region subject to correction, in which pixels having at most a predetermined brightness level appear with a frequency equal to or less than a predetermined value. An offset level generation circuit (10) generates an offset level (Offset) on the basis of the brightness of the pixels determined to be within the region subject to correction. An offset subtraction circuit (1) subtracts the offset level (Offset) from the image signal (Yi) to generate an offset image signal (Yofst). A gain generation circuit (20) generates a gain for the offset image signal (Yofst). A gain multiplication circuit (2) multiplies the offset image signal (Yofst) by the gain to generate a corrected image signal (Ya).

主权项

1. An image processing method comprising:
a region decision step of deciding whether each pixel of an image represented by an image signal is disposed within a region subject to correction, in which pixels having at most a predetermined brightness level appear with a frequency equal to or less than a predetermined value; an offset level generation step of generating an offset level on a basis of the brightness of those pixels in the image represented by the image signal which are determined in the region decision step to be within the region subject to correction; an offset subtraction step of subtracting the offset level generated in the offset level generation step from the image signal to generate an offset image signal; a gain generation step of generating a gain for the offset image signal; and a gain multiplication step of multiplying the offset image signal by the gain to generate a corrected image signal; a mixing ratio generation step of generating a mixing ratio for each pixel of the image represented by the image signal on a basis of a low brightness pixel ratio, which is a proportion of pixels having at most the predetermined brightness level to pixels surrounding said each pixel; and a mixing step of mixing the image signal and the corrected image signal on a basis of the mixing ratio.