Should not the GLDM matrix in the example in shape of (5, 9) for 2D images? Or the 0s after size 4 are trimmed because the counts are all 0s?
As a two dimensional example, consider the following 5x5 image, with 5 discrete gray levels:
$$
\textbf{I} = \begin{bmatrix}
5 & 2 & 5 & 4 & 4\\
3 & 3 & 3 & 1 & 3\\
2 & 1 & 1 & 1 & 3\\
4 & 2 & 2 & 2 & 3\\
3 & 5 & 3 & 3 & 2 \end{bmatrix}
$$
For $\alpha=0$ and $\delta = 1$, the GLDM then becomes:
$$
\textbf{P} = \begin{bmatrix}
0 & 1 & 2 & 1 \\
1 & 2 & 3 & 0 \\
1 & 4 & 4 & 0 \\
1 & 2 & 0 & 0 \\
3 & 0 & 0 & 0 \end{bmatrix}
$$
Should not the GLDM matrix in the example in shape of (5, 9) for 2D images? Or the 0s after size 4 are trimmed because the counts are all 0s?