Fig. 5.

A (a) malignant mass, (b) its original segmentation mask and (c) different regions defined for computation of the contrast-based features: I₁ (innermost lighter gray region of the mass), I₂ (white region of the mass adjacent to its contour), and O (darker gray background region). Three sets of contrast features are computed from (1) between O and I whereby I is the interior segment of the mass within its contour (I₁ + I²), (2) between O and I₁, and (3) between O and I₂