1. A method for performing illumination normalization on a digital image, comprising: receiving an input image in which at least one spurious edge directly resulting from illumination present when the input image was acquired is included with at least one real edge resulting from an underlying structure of a subject or scene within the input image; performing anisotropic diffusion on the input image to form an illumination image which has contrast variation corresponding to the spurious edge resulting from the illumination; and distinctively removing at the least one spurious edge using the illumination image.