1. An automated, computerized method for processing an image, comprising the steps of: providing an image file depicting an image, in a computer memory; determining illumination invariant log chromaticity representations for the image; clustering the log chromaticity representations to provide clusters of similar log chromaticity representations; and identifying regions of uniform reflectance in the image as a function of the clusters of similar log chromaticity representations, the regions of uniform reflectance including illumination variation in the image across at least some of the regions of uniform reflectance.