Abstract: A method and apparatus for enhancing the contrast of a local area of interest within an electronic image of an object, such as a female breast, which has been transilluminated by non-ionizing radiation such as light or sound. The area of interest may be a cancerous tumor, cyst or another object which differentially absorbs or transmits the radiation. Enhancement of contrast is by normalization of the electronic image. Normalization includes modeling the illumination field of the image to compensate for the non-uniformity of the illumination field, and then combining the modeled field with the original image. Four normalization processes are disclosed: Gaussian curve fitting, geometric mean smoothing, arithmetic mean smoothing, and arithmetic mean smoothing only within the boundary of the local area of interest. Also disclosed is a process for highlighting local areas which are the result of enhanced transmission of the radiation, such as potential cyst sites, and color mapping more than one displayed image.