Loadable Function: P = graycomatrix(im, levels, distances, angles)

Calculates the gray-level co-occurrence matrix P of a gray-level image im.

P is a 4-dimensional matrix (histogram). The value P(i,j,d,theta) is the number of times that gray-level j occurs at a distance d and at an angle theta from gray-level i.

im is the input image which should contain integers in [0, levels-1], where levels indicate the number of gray-levels counted (typically 256 for an 8-bit image). distances and angles are vectors of the different distances and angles to use.

Demonstration 1

The following code


  # Pattern Recognition Engineering (Nadler & Smith)
  # Digital Image Processing (Gonzales & Woods), p. 668

  a = [0 0 0 1 2;
       1 1 0 1 1;
       2 2 1 0 0;
       1 1 0 2 0;
       0 0 1 0 1];

  graycomatrix(a, 3, 1, [0 1]*-pi/4)

Produces the following output

ans =

ans(:,:,1,1) =

   2   5   1
   5   1   2
   1   3   0

ans(:,:,1,2) =

   4   2   0
   2   3   2
   1   2   0

Package: image