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.

Abstract: Optical apparatus for scanning radiation over a surface includes a plurality of angularly spaced rotating arms extending from a central axis. A central reflector is positioned at the axis of the arms and a radially remote reflector is positioned on each arm for folding an optical radiation path toward the object to be scanned. The central reflector rotates with the arms but is sequentially indexed into optical path alignment with each radially remote reflector so that a beam of radiation in the optical path is scanned over the same predetermined arcuate segment by each of the remote reflectors.