METHOD FOR DETERMINING WHETHER PHOTOGRAPHIC IMAGE IS DIFFERENT-LIGHT-SOURCE PHOTOGRAPHIC IMAGE AND PHOTOGRAPHIC IMAGE PROCESSING APPARATUS

Data on a target film image is developed so as to correspond to a predetermined X-Y two-dimensional coordinate system representing a relationship between RGB average data on each constituent pixel and respective color component data, developed pixels are divided to a plurality of groups so that pieces of the RGB average data on the respective pixels are arranged equidistantly, an average of dissociations of the respective pixels relative to a reference line representing characteristics of a film image photographed by a standard light is operated and derived as a group difference sum for each of the divided groups, for each of R, G, and B, a thickness factor for normalizing a distribution thickness of a pixel distribution in a direction in which the pixel distribution is distanced from the reference line is operated and derived, for each of the divided groups, an image difference sum is operated and derived by a product-sum operation between the group difference sum and the thickness factor, and if the image difference sum for the R, G, or B is greater than a predetermined value, the target film image is determined as a photographic image photographed using different types of light sources.