Table 3.

List of features that were selected in more than 50% of the cross validation runs from local and global regions.

Local Feature	Description	Percentage	Local Feature	Description	Percentage	Global Feature	Description	Percentage
F1	coefficient of variance of $r_M^H$	100% (566/566)	F7	range of $S_M^V$	100% (566/566)	F1	$c_G^V$	69.96% (396/566)
F2	kurtosis of $r_M^H$	100% (566/566)	F8	median of ρ3	98.06% (555/566)	F2	sum of ρ0	100% (566/566)
F3	max of $a_G^V$	100% (566/566)	F9	standard deviation of ρ4	100% (566/566)	F3	max of ρ0	99.82%(565/566)
F4	max of $a_P^V$	63.43% (359/566)	F10	max of θ6	99.47% (563/566)	F4	SP	100% (566/566)
F5	median of $r_P^V$	100% (566/566)	F11	min of θ6	99.47% (563/566)	F5	~ SG	96.64%(547/566)
F6	mean deviation of $S_P^H$	98.06% (555/566)	—	—		F6	~ SP	100% (566/566)

Note. a, c, and r: semivariogram descriptors that stand for nugget, sill and range, respectively. S and ŝ : structural similarity descriptors that stand for Structural Similarity index and Correlation-Based Structural Similarity index, respectively. ρ and θ : position information descriptors, namely distance and angle, respectively. H and V: horizontal masking/direction and vertical masking/direction, respectively. G, M and P: grayscale values, the magnitude and phase responses of multidirectional Gabor filters, respectively. 0-6: 0 indicates DoG basic element regions spread over the whole breast region, 1-6 indicate DoG basic element regions spread over the first sub-region to the 6^th sub-region. For example, $r_M^H$ indicates the range from the magnitude of Gabor filters for horizontal strips; Ŝ_G stands for the CB-SSIM index from grayscale values; and ρ₃ stands for the radius of DoG basic element regions spread over the 3rd sub-region.