An improved non-linear transformation function for enhancement of mammographic breast masses

Breast cancer is often diagnosed at its early stage as a non-palpable suspicious mass on a mammogram that may be cancerous at a later stage. Masses can be seen in both mediolateral and craniocaudal mammographic views. Masses with diameters less than 1 cm are generally benign, while those with diameters above 2 cm require further investigation. This paper presents a novel approach for enhancement of suspicious masses in mammographic images using the proposed nonlinear transformation function. Significant improvement in contrast of masses along with the suppression of background tissues is obtained by tuning the parameters of the proposed transformation function in the specified range. The selection of parameters is almost invariant of the type of background tissues and severity of the abnormality, giving significantly improved results even for denser mammographic images. The applicability of the proposed method is tested on mammograms with circumscribed, ill-defined and spiculated masses.