Let’s see in these series
of posts on how to extract the texture features from Grey Level Co-occurrence Matrix
(GLCM) in MATLAB. In simple terms, GLCM gives
the spatial relationship between adjacent or neighbouring pixels. And from this
GLCM Matrix, we will measure some texture features.
Let’s consider a simple
example and start coding the steps in terms of algorithmic as well as
programming in MATLAB.
Procedure to Generate GLCM Matrix:
MATLAB
CODE:
clear all
%GLCM MATRIX
A=[1 2 3 2 3; 1 2 3 4 5; 4 4 1 1
4; 6 7 6 7 6; 1 8 1 8 8];
Displacement = 1; %NUMBER OF
STEPS BETWEEN TWO PIXELS
NumQuantLevels = 8; %QUANTIZATION
LEVEL
glcm =
zeros([NumQuantLevels,NumQuantLevels]); %PREALLOCATE GLCM MATRIX
for i = 1:size(A,1)
for j = 1 :size(A,2)-1
glcm(A(i,j),A(i,j+1))=glcm(A(i,j),A(i,j+1))+1;
%INCREMENT
BY 1
end
end
EXPLANATION:
The number of occurrences
of a pixel and its neighboring pixel is calculated. The offset is 1 and it can
be incremented based on the requirement. Here the direction of the pixel
movement is towards the right. The maximum value of the pixel in the matrix A
is 8 so the quantization level is fixed to 8. For instance, in the example
given above, the pixel 2 and its neighbor 3 occurs 3 times in matrix A and it
is updated in the GLCM matrix at the position (2,3) as 3.
Continue Reading: Texture Measures from GLCM - MATLAB CODE
Continue Reading: Texture Measures from GLCM - MATLAB CODE
