Patent ID: 7139425

Claim:
A method of correcting white balance, comprising the steps of: estimating, by using at least gray and/or skin color information contained in an input color image, a color temperature of a photographing light source with which a color image has been formed; and correcting an image signal of the color image based on the estimated color temperature, wherein said estimating step includes: multiplying image signals of each pixel in the input color image by set coefficients; setting pixels having the multiplied image signals in the vicinity of a blackbody locus curve of skin color as skin color candidate pixels and/or pixels having the multiplied image signals in the vicinity of a blackbody locus curve of gray as gray candidate pixels; optimizing the set coefficients so that the number of the skin color candidate pixels and/or the gray candidate pixels is maximized; obtaining a group of skin color candidate pixels and/or a group of gray candidate pixels by using the optimized set coefficients; and estimating said color temperature of said photographing light source from an average color temperature of the group of skin color candidate pixels and/or an average color temperature of the group of gray candidate pixels, and wherein said image signals of the color image multiplied by the optimized set coefficients are corrected by an amount corresponding to a difference between the estimated color temperature and a color temperature of reference white.