Segmentation & confusion matrix for colored image; matrix dimensions must agree.

Question

bayoishola20 2014-9-22

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https://ww2.mathworks.cn/matlabcentral/answers/155726-segmentation-confusion-matrix-for-colored-image-matrix-dimensions-must-agree

回答： Nurudeen Ayanleye Yusuff 2018-7-22

Pls I'm having issues getting my confusion matrix done. Below are all code-files and picture '1.jpg' is NOT a monochrome image. On plotting the confusion matrix, it keeps giving me

'matrix dimensions must agree'

thank u for the quick response.

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Sreeja Banerjee 2014-9-29

I see that your code requires the file '1.jpg' in order to execute. Could you please attach the file so that I can try to reproduce the error?

bayoishola20 2014-10-2

okay! Thank you so much, here is the file

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Answer 1

Ping-Chang Shih 2014-9-29

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https://ww2.mathworks.cn/matlabcentral/answers/155726-segmentation-confusion-matrix-for-colored-image-matrix-dimensions-must-agree#answer_153281

Given that the input image is not a monochrome image, all elements in your "segmented_images" cell array have three dimensions. However, the polygonal ROI image you create (stored as variable "BW_1") has two dimensions. Plugging the two types of variables into the MATLAB "confusion" function causes an error since the two arguments are expected to have the same number of dimensions.

The above conclusion is obtained from my interpretation of your code. If I misunderstood your code, please let me know.

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Image Analyst 2014-10-10

Are you still having trouble? If so, post your latest code.

bayoishola20 2014-10-10

编辑：bayoishola20 2014-10-10

在 MATLAB Online 中打开

Yes I am.

For image segmentation.

he= imread('C:\Users\ISHOLA\Desktop\1.jpg');
imshow(he), title('ORIGINAL IMAGE');
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;
[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

For dataset training;

%training of classes
imshow(he);
%Training of class 1
BW_1=roipoly(he);
%Training of class 2
BW_2=roipoly(he);
%Training of class 3
BW_3=roipoly(he);
%Training of class 4
BW_4=roipoly(he);
%Training of class 5
BW_5=roipoly(he);
%Training of class 6
BW_6=roipoly(he);

On the aspect of the confusion Matrix, I don't really know how to put it although I know that "pixel_labels" is what I need from the segmentation done. I tried this for instance and it tells me

'Index exceeds matrix dimensions.'
confusionMatrix(r,c)=confusionMatrix(pixel_labels==1,BW_1) +1;

But how to get it right to plot the confusion matrix is what I don't still understand. Thank you.

Thanks for the help on this link though still need your help. http://www.mathworks.com/matlabcentral/answers/157393-kmeans-image-segmentation-and-confusion-matrix

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Answer 2

Nurudeen Ayanleye Yusuff 2018-7-22

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https://ww2.mathworks.cn/matlabcentral/answers/155726-segmentation-confusion-matrix-for-colored-image-matrix-dimensions-must-agree#answer_329807

please i need code for ISODATA which i will implement in my GUI i created. Also i need how to code accuracy assessment for classified image using kmean of unsupervised classification