Patent US 4,340,911

A method of and apparatus for processing a mammogram in a mammogram copying system in which an original mammogram is scanned with a scanning light beam and the light transmitted through the mammogram is detected by a photodetector which gives an output to be processed and used for recording a visible image on a recording medium. The image gradation of the mammogram is processed. The gradation processing is characterized in that the minimum density of the glandular tissue of the mammogram is lowered down to the level of the fog density to raise the contrast of the mammogram.