Neural Network Code for Image Classifica​tion/Segme​ntation

I have written a code in Matlab for neural network classification/segementation the image after train the image. But, it is not working as expected. I get the error in this line "yhat = net(double([r;g;b]));". Is there any mistake in the code? Can you take a look at the code and help me out !!

a = imread('C:\Users\user\Desktop\MATLAB PROCESSING\Matlab Processing\Band432\open land\klang.tif');
b = rgb2gray(a);
figure, imshow(a);
figure, imshow(b);
thr = 0.5;
for i = 1:1:size(a,1)
  for j = 1:1:size(a,2)
      pix = a(i,j,:);
      r = pix(1,1,1);
      g = pix(1,1,2);
      b = pix(1,1,3);
      yhat = net(double([r;g;b]));
      if yhat >= thr
          result = 1;
          b(i,j) = 255;
      else
          result = 0;
          b(i,j) = 0;
      end
  end
end
figure3, imshow(b)

or any suggestion code for classify the image in 5-class

I really hope can get any feedback because I really not familiar with neural network toolbox

[Greg Heath]

I don't know. However, searching on

 NEURAL IMAGE SEMENTATION

resulted in 32 hits in ANSWERS and 33 hits in the NEWSGROUP.

Hope this helps.

Greg