How do I retrieve texture using GLCM and classify using SVM Classifier?

Question

I'm on a project of liver tumor segmentation and classification. I used Region Growing and FCM for liver and tumor segmentation respectively. Then, I used Gray Level Co-occurence matrix for texture feature extraction. I have to use Support Vector Machine for Classification. But I don't know how to normalize the feature vectors so that I can give it as an input to the SVM. Can anyone tell how to program it in Matlab?

To the GLCM program, I gave the tumor segmented image as input. Was I correct? If so, I think, then, my output will also be correct.

My glcm coding, as far as I have tried is,

I = imread('fzliver3.jpg');
GLCM = graycomatrix(I,'Offset',[2 0;0 2]);
stats = graycoprops(GLCM,'all')
t1= struct2array(stats)


I2 = imread('fzliver4.jpg');
GLCM2 = graycomatrix(I2,'Offset',[2 0;0 2]);
stats2 = graycoprops(GLCM2,'all')
t2= struct2array(stats2)

I3 = imread('fzliver5.jpg');
GLCM3 = graycomatrix(I3,'Offset',[2 0;0 2]);
stats3 = graycoprops(GLCM3,'all')
t3= struct2array(stats3)

t=[t1,t2,t3]
xmin = min(t); xmax = max(t);
scale = xmax-xmin;
tf=(x-xmin)/scale

Was this a correct implementation? Also, I get an error at the last line.

My output is:

stats = 

   Contrast: [0.0510 0.0503]
Correlation: [0.9513 0.9519]
     Energy: [0.8988 0.8988]
Homogeneity: [0.9930 0.9935]
t1 =

Columns 1 through 6

0.0510    0.0503    0.9513    0.9519    0.8988    0.8988
Columns 7 through 8

0.9930    0.9935
stats2 = 

   Contrast: [0.0345 0.0339]
Correlation: [0.8223 0.8255]
     Energy: [0.9616 0.9617]
Homogeneity: [0.9957 0.9957]
t2 =

Columns 1 through 6

0.0345    0.0339    0.8223    0.8255    0.9616    0.9617
Columns 7 through 8

0.9957    0.9957
stats3 = 

   Contrast: [0.0230 0.0246]
Correlation: [0.7450 0.7270]
     Energy: [0.9815 0.9813]
Homogeneity: [0.9971 0.9970]
t3 =

Columns 1 through 6

0.0230    0.0246    0.7450    0.7270    0.9815    0.9813
Columns 7 through 8

0.9971    0.9970

t =

Columns 1 through 6

0.0510    0.0503    0.9513    0.9519    0.8988    0.8988

Columns 7 through 12

0.9930    0.9935    0.0345    0.0339    0.8223    0.8255

Columns 13 through 18

0.9616    0.9617    0.9957    0.9957    0.0230    0.0246

Columns 19 through 24

0.7450    0.7270    0.9815    0.9813    0.9971    0.9970

??? Error using ==> minus
    Matrix dimensions must agree.

The input images are:

Answer 1

Are you using Matlab? If so then you would either need the Bioinformatics Toolbox, that includes an SVM classifier, or you can download libsvm, which has Matlab wrappers for training and testing.

Then you are going to need some labeled data. Are you classifying liver tummors as opposed to healthy liver? Then you would need images of liver tumors and healthy livers, each labeled as such.

Then you need to compute some features. What those are, depends on the nature of the problem. Texture features seem like a good start. Consider using co-occurrence matrices or local binary patterns.

Edit: As of the R2014a release there is a fitcsvm function in the Statistics and Machine Learning Toolbox for training a binary SVM classifier. There is also fitcecoc for training a multi-class SVM.

Answer 2

This article deals exactly with the same type of supervised classification based on labelled GLCM classes: GLCM Textural Features for Brain Tumor Classification