Method for determining whether a photographic image was captured under unusual lighting conditions and photographic image processing apparatus

摘要

Data on a target film image is processed so as to correspond to a predetermined X-Y two-dimensional coordinate system with an X axis indicating the average of R, G and B data on each constituent pixel and a Y axis indicating respective color component data, processed pixels are divided to a plurality of groups of RGB average data, whereby the groups are arranged equidistantly along the X axis, an average of distances 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 types of light sources, different from the standard solar light or strobe light.