Table 2.

Extracted texture features.

IHIST	GLCM*	GLGCM*	ISZFs
Mean	Mean/diff energy	Small gradient emphasis	Small zone emphasis
Variance	Mean/diff entropy	Large gradient emphasis	Large zone emphasis
Median	Mean/diff correlation	No homogeneity of gray	Gray intensity change
Maximum	Mean/diff contrast	No homogeneity of gradient	Zone size change
Minimum	Mean/diff homogeneity	Energy	Zone percentage
Up quarter value	Mean/diff variance	Mean of gray	High intensity emphasis
Down quarter value	Mean/diff mean	Mean of gradient	Low intensity small zone emphasis
Energy	Mean/diff inertia	Variance of gray	High intensity small zone emphasis
Entropy	Mean/diff cluster shade	Variance of gradient	Low intensity large zone emphasis
Skewness	Mean/diff cluster tendency	Correlation of gradient	High intensity large zone emphasis
Kurtosis	Mean/diff max probability	Entropy of gray
	Mean/diff inverse variance	Entropy of gradient
	Mean/diff inverse difference moment	Mix entropy
	Mean/diff sum mean	Inertia
	Mean/diff sum entropy	Inverse difference moment
	Mean/diff difference entropy

IHIST, Intensity histogram texture; GLCM, gray level co-occurrence matrix; GLGCM, gray level gradient co-occurrence; ISZFs, Intensity size-zone variability features; diff, the extreme difference of feature.

^*128 GLCM features are constructed by 64 mean values and 64 extreme difference values. Similarly, 60 gray gradient features were extracted from GLGCM.