1. For use in a vehicle, an automated, computerized method for processing an image, comprising the steps of: receiving from a digital camera mounted on the vehicle, an image file depicting pixels of an image of a scene related to vehicle operation on a road, each one of the pixels having N band color values; determining a lit road color range; transforming the N bands to log color space values in a log color space; generating a log chromaticity plane in the log color space; identifying pixels within the lit road color range and meeting criteria indicating suitability for use in determining an accurate orientation for the log chromaticity plane, according to a BIDR model, carried out by calculating a gradient for each one of the pixels within the lit road color range, and analyzing the gradients for indicia of being located on a shadow boundary; using the identified pixels to sample image color at each of pre-selected bright and dark locations relative to each one of the identified pixels, carried out by selecting dark and bright locations spaced a pre-selected distance in negative gradient and gradient directions, respectively, from each one of the identified pixels, and sampling image color at each selected location, and calculate, for each one of the identified pixels, an orientation according to the BIDR model, for the log chromaticity plane, as a function of the sample image color, to provide a set of proposed orientations; using the set of proposed orientations to identify a dominant orientation; orienting the log chromaticity plane in the dominant orientation; projecting the log color space values to the chromaticity plane to provide chromaticity representation values corresponding to the pixels of the image; and using the chromaticity representation values corresponding to the pixels to generate an illumination invariant image of the scene.