Matrix Dimension Must Agree

I've trained six(6) classes of features & performed image segmentation but trying to ascertain the accuracy of this, but it keeps telling me 'matrix dimension must agree' among the run error. Below is my segmentation code as well as roi.

"1.jpg" is not a gray image.

he= imread('C:\Users\ISHOLA\Desktop\1.jpg');
  imshow(he)
  cform = makecform('srgb2lab'); 
  lab_he = applycform(he,cform); 
  ab = double(lab_he(:,:,2:3)); 
  nrows = size(ab,1); 
  ncols = size(ab,2);
  disp(nrows); 
  disp(ncols); 
  ab = reshape(ab,nrows*ncols,2); 
  nColors = 6; 
  % repeat the clustering 3 times to avoid local minima 
  [cluster_idx cluster_center] = kmeans(ab,nColors,'distance','sqEuclidean','replicates',6); 
  pixel_labels = reshape(cluster_idx,nrows,ncols); 
  %figure, 
imshow(pixel_labels,[]), title('image labeled by cluster index'); 
  segmented_images = cell(1,3); 
  rgb_label = repmat(pixel_labels,[1 3]);

    for 
    k = 1:nColors 
    color = he;
    color(rgb_label ~= k) = 0;
    segmented_images{k} = color;
    end

ROI(Region of Interest);

BW_1=roipoly(he); %for class 1

But on running this for the confusion matrix,it doesn't work

[c,cm,ind,per] = confusion(BW_1,segmented_images{1});

[Image Analyst]

Please read http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup and fix your post.

[bayoishola20]

okay! Thanks & apology for that.

[Image Analyst]

You forgot to post the error message - you just snipped out a small part of all the red text and told us just the small part. I don't even know what line it errored on. But anyway, I don't have the stats toolbox so I can't run it anyway but someone else might.

[bayoishola20]

okay!thanks on that!