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 for the pixels of the image; generating an illumination-invariant image representation of the image based upon pixels in the lit road color range and as a function of a BIDR model; wherein the step of determining a lit road color range for the pixels of the image is carried out by identifying pixels with an approximately neutral value, within a pre-specified intensity range, forming a histogram of color intensity relative to the N band color values, the histogram containing bins based upon the intensity range, each one of the bins indicating a pixel number count for one value in the intensity range, and determining the lit road color range as a function of numbers of pixels in the bins.