Image analysis through GLCM Matrix

Question

I have a image for which I have to calculate the GLCM texture of a selected region. How can I calculate this? I have to calculate the GLCM only for gray area.

Answer 1

To create a Grey-Level Co-occurrence Matrix you simply count how often certain grey Values are Neighbours.

An Example:

Image
1 1 0 2 
1 2 2 2
2 2 1 0

Now we define our GLCM as:

GLCM
     0     1     2
   ------------------
0 | (0,0) (0,1) (0,2)
  |
1 | (1,0) (1,1) (1,2)
  |
2 | (2,0) (2,1) (2,2)

Where (x,y) denotes that how often is the Value y right of the Value x

For our Example we get:

GLCM
    0     1     2
   ------------------
0 | 0     0     1
  |
1 | 2     1     1
  |
2 | 0     1     3

You can extend this to get more than only the next neighbour or adjust the direction (North, East, South-East etc.) you look for a neighbour if this gives any benefits to your application. You can even create GLCM for every Pixel direction.

After that you can achieve a symmetricall GLCM by counting again but interchanging the position of x and y to get (y,x).

After you have a symmetrical GLCM you can normalize it to get your GLCM Texture.

There is an excellent Paper from Haralick et.al. that you can read: Textural Features for Image Classification.