Contrast enhancement of mammogram by image processing
Ying Xiong, Chan F. Lam, G. Donald Frey, M R Croley · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1993
Digital mammography has great potential effect on the management of breast cancer. With an appropriate image processing technique, the sensitivity and specificity of tumor detection in mammography may be improved further. Small objects such as microcalcifications in mammograms have low contrast because of the high x-ray penetration of the objects, scattered radiation, and the limited capability of film to develop maximum contrast over an extended range of exposure values. Low contrast tumors may be missed by radiologists during mammogram reading. Standard image processing techniques, such as gray-level histogram equalization, spatial filtering and/or unsharp masking, do not perform well on mammographic images due to large variation in feature size and shape as well as the variation of normal background tissues. This paper presents a technique based on local contrast histogram modification. We associate a contrast value with each pixel in the image. The contrast of a pixel with respect to its background is enhanced by modifying the contrast histogram. The following section gives a brief review of contrast enhancement techniques for mammographic images.