GLSZM_global_features

The feature definitions are available in IBSI section 4.8

List of available features

1. Small Area Emphasis (SAE)

$\frac{\sum^{N_g}_{i=1}\sum^{N_s}_{j=1}{\frac{\textbf{P}(i,j)}{j^2}}}{N_z}$

2. Large Area Emphasis (LAE)

$\frac{\sum^{N_g}_{i=1}\sum^{N_s}_{j=1}{\textbf{P}(i,j)j^2}}{N_z}$

3. Gray Level Non-Uniformity (GLN)

$\frac{\sum^{N_g}_{i=1}\left(\sum^{N_s}_{j=1}{\textbf{P}(i,j)}\right)^2}{N_z}$

4. Gray Level Non-Uniformity Normalized

$\frac{\sum^{N_g}_{i=1}\left(\sum^{N_s}_{j=1}{\textbf{P}(i,j)}\right)^2}{N_z^2}$

5. Size Zone Non-Uniformity (SZN)

$\frac{\sum^{N_s}_{j=1}\left(\sum^{N_g}_{i=1}{\textbf{P}(i,j)}\right)^2}{N_z}$

6. Size Zone Non-Uniformity Normalized

$\frac{\sum^{N_s}_{j=1}\left(\sum^{N_g}_{i=1}{\textbf{P}(i,j)}\right)^2}{N_z^2}$

7. Zone Percentage (ZP)

$\frac{N_z}{N_p}$

8. Low Gray Level Zone Emphasis (LGLZE)

$\frac{\sum^{N_g}_{i=1}\sum^{N_s}_{j=1}{\frac{\textbf{P}(i,j)}{i^2}}}{N_z}$

9. High Gray Level Zone Emphasis (HGLZE)

$\frac{\sum^{N_g}_{i=1}\sum^{N_s}_{j=1}{\textbf{P}(i,j)i^2}}{N_z}$

10. Small Area Low Gray Level Emphasis (SALGLE)

$\frac{\sum^{N_g}_{i=1}\sum^{N_s}_{j=1}{\frac{\textbf{P}(i,j)}{i^2j^2}}}{N_z}$

11. Small Area High Gray Level Emphasis (SAHGLE)

$\frac{\sum^{N_g}_{i=1}\sum^{N_s}_{j=1}{\frac{\textbf{P}(i,j)i^2}{j^2}}}{N_z}$

12. Large Area Low Gray Level Emphasis (LALGLE)

$\frac{\sum^{N_g}_{i=1}\sum^{N_s}_{j=1}{\frac{\textbf{P}(i,j)j^2}{i^2}}}{N_z}$

13. Large Area High Gray Level Emphasis (LAHGLE)

$\frac{\sum^{N_g}_{i=1}\sum^{N_s}_{j=1}{\textbf{P}(i,j)i^2j^2}}{N_z}$

14. Grey Level Variance

$\displaystyle\sum^{N_g}_{i=1}\displaystyle\sum^{N_s}_{j=1}{p(i,j)(i - \mu)^2}$

15. Size Zone Variance

$\displaystyle\sum^{N_g}_{i=1}\displaystyle\sum^{N_s}_{j=1}{p(i,j)(j - \mu)^2}$

where
is the total number of gray levels in the image.
is the total number of zone sizes in the image.
is the total number of voxels in the image.
is the number of zones in the image.
$\textbf{P}(i,j|\theta)$ is the size zone matrix.
$p(i,j) = \frac{\textbf{P}(i,j)}{N_z}$ is the normalized size zone matrix.
$\mu = \displaystyle\sum^{N_g}_{i=1}\displaystyle\sum^{N_s}_{j=1}{p(i,j)i}$