Straight Line Approximation of Pectoral Muscle in Mammogram Using the Method of Optimum Thresholding

In Medio-Lateral Oblique (MLO) view of mammogram, the presence of pectoral muscle may sometimes affect the detection of architectural distortion due to their similar characteristics with abnormal tissues. As a result pectoral muscle should be handled separately while detecting the breast cancer. The straight line approximation of pectoral muscle is also very important in obtaining the breast tissue architecture, which helps to detect the presence of architectural distortion. In this paper, a novel approach for the straight line approximation of pectoral muscle using optimum thresholding is proposed. The process first selects an optimum threshold based on average gray level and Otsu´s threshold. The selected region of interest (ROI) of the image is thresholded based on the optimum threshold and approximates the pectoral muscle boundary as a straight line. A set of images was selected for testing and the method is found to have an accuracy of 86.67%.