Montage of several different images

Function montage_images(X, Y) where X is a M-by-D data matrix (of floating-point numbers in double-precision format, which is the default in Matlab), where M is the number of samples, and D is the the number of elements in a sample. Note that each sample is represented as a row vector rather thana column vector. Y is a M-by-1 label vector (of uint8) for X. Y(i)is the class number ofX(i,:) which are just class labels

So, I've loaded in the dataset (not shown) and there's ten sets of this, of which I need to create a montage of the first 10 samples of each set. So, I have two for-loops and I've managed to get the images, but I'm stuck on how to compile each set of 10 images and then making it display with montage. It seems that montage doesn't play nicely with image format or something?

The X = Xtrn2(Y==k, :) gets the associated set # (1,2, .., 10).

Any help/hints would be greatly appreciated.

Answer 1

[Geoff Hayes]

From montage, the input parameter can be list of filenames or a list of images. You are providing (if I understand your code) a (single) graphics object or handle to an image. I think that you want to create the images first and then provide this list of images to the function montage. Your code would then look something like

myImages = cell(1,10);
for k = 1:10
    myImages{k} = reshape(X(k,:)*255.0, 28, 28)';
end
montage(myImages);

The above may work (I haven't tested it) but hopefully it will give an idea of why your code may not be working as expected.

[John Doe]

Is it possible to open all 10 different montages in their own separate windows at once? After implementing this snippit, it opens all of them, but it quickly flashes through all of them in one single window and finishes on the last set of 10 images montage.

Thanks

[Geoff Hayes]

You can try adding a call to figure before your call to montage:

myImages = cell(1,10);
for k = 1:10
    myImages{k} = reshape(X(k,:)*255.0, 28, 28)';
end
figure;
montage(myImages);