Table 2.

Variables and notations used to compute the texture features.

Notation	Definition
x (i, j)	Element i, j in the GLCM
N	Number of gray levels
p (i, j)	$\frac{x\left(i,j\right)}{{{\displaystyle \sum }}_{i=1}^N{{\displaystyle \sum }}_{j=1}^{N}x\left(i,j\right)}$
$p_x\left(i\right)$	${{\displaystyle \sum }}_{j=1}^{N}p\left(i,j\right)$
$p_y\left(j\right)$	${{\displaystyle \sum }}_{i=1}^{N}p\left(i,j\right)$
${\mu }_x$	${{\displaystyle \sum }}_{i=1}^{N}i·p_x\left(i\right)$
${\mu }_y$	${{\displaystyle \sum }}_{j=1}^{N}j·p_y\left(j\right)$
${\sigma }_x^2$	${{\displaystyle \sum }}_{i=1}^N{\left(i-{\mu }_x\right)}^2·p_x\left(i\right)$
${\sigma }_y^2$	${{\displaystyle \sum }}_{j=1}^N{\left(j-{\mu }_y\right)}^2·p_y\left(i\right)$
$p_{x+y}\left(k\right)$	${{\displaystyle \sum }}_{i=}^N{{\displaystyle \sum }}_{j=1 }^N{ }_{k=i+j}\hspace{1em}p\left(i,j\right)$
$p_{x-y}\left(k\right)$	${{\displaystyle \sum }}_{i=}^N{{\displaystyle \sum }}_{j=1 }^N{ }_{k=\left|i-j\right|}\hspace{1em}p\left(i,j\right)$
${\mu }_{x+y}$	${{\displaystyle \sum }}_{k=2}^{2N}k·p_{x+y}\left(k\right)$
${\mu }_{x-y}$	${{\displaystyle \sum }}_{k=0}^{N-1}k·p_{x-y}\left(k\right)$
HX	$-{{\displaystyle \sum }}_{i=1}^N{p}_x\left(i\right)·\log p_x\left(i\right)$
HY	$-{{\displaystyle \sum }}_{i=1}^N{p}_y\left(i\right)·\log p_y\left(i\right)$
HXY	$-{{\displaystyle \sum }}_{i=1}^N{{\displaystyle \sum }}_{j=1}^{N}p\left(i,j\right)·\log p\left(i,j\right)$
HXY1	$-{{\displaystyle \sum }}_{i=1}^N{{\displaystyle \sum }}_{j=1}^{N}p\left(i,j\right)·\log \left[p_x\left(i\right)·p_y\left(j\right)\right]$
HXY2	$-{{\displaystyle \sum }}_{i=1}^N{{\displaystyle \sum }}_{j=1}^N{p}_x\left(i\right)·p_y\left(j\right)·\log \left[p_x\left(i\right)·p_y\left(j\right)\right]$