How to display matrix as an image ?

I have a diagonal matrix A of 4x4 and I want to display this as an image, how am I supposed to do that? I tried using imshow(A) and it does not work, please help.

[Baptiste Ottino]

Could you be more precise please? What type is your matrix? What error does imshow return? imshow should be the right function here, so the problem is elsewhere.

[Adam]

figure; imagesc(A)

Answer 1

[Reen]

Try using:

 image(A)

That will display the image like a heatmap with each entry being a square. If you want to specify the color of each square, you'll have to use a 3 dimensional array. For example if you use something like:

 A(:,:,1) = [255 0 255 0; 0 255 0 255; 255 0 255 0; 0 255 0 255];
 A(:,:,2) = [255 0 255 0; 0 255 0 255; 255 0 255 0; 0 255 0 255];
 A(:,:,3) = [255 0 255 0; 0 255 0 255; 255 0 255 0; 0 255 0 255];
 % A(1,1,:) is the rgb color vector, so white for A(1,1,:) = [255 255 255] and black for A(1,2,:) = [0 0 0]
 image(A)

you'll get something that looks like a checkerboard.