MASS DETECTION BY COMPUTER USING DIGITAL MAMMOGRAMS OF THE SAME BREAST TAKEN FROM DIFFERENT VIEWING DIRECTIONS

Two digital radiologic images taken from different viewing directions of a same region, notably a mammogram study of the same breast, are automatically processed by a computer to identify suspect masses by producing processed mammogram images in which suspect spots, the skinline and the nipple are marked or enhanced. Candidate suspect spots are initially identified by individually processing each mammogram image separately. Then characteristics of the candidate spots identified in the mammogram images taken from different viewing directions are compared to eliminate false positives. The characteristics compared include position of the spots relative to the explicitly detected nipple, and their size, shape, brightness and brightness variance. The candidate spots are separately identified by thresholding the breast region of the mammogram at 20 or more threshold levels determined from a histogram of the image to discriminate spots, and classifying the spots by size, shape and variance in intensity of the pixels comprising the spot. Overlaps are resolved after the comparison between views.