Access difference between 3 dimensional matrices

I have two matrices,A is a 1000*1000*3 matrix and B is another matrix that started out as A and due to changes made during the code is a different 1000*10000*3 matrix. I would like to find out the position and the number of elements that have not changed. This for two D matrices can be done with setdiff, is there any way I can do this for 3D matrices? Thanks

Answer 1

[Matt J]

 [i,j,k] = ind2sub(size(A), find(A==B));

 NumberUnchanged=length(i);

[Samadrita]

I am a bit confused as to how this is working. For example I have a 5052*6492*3 matrix. But the NumberUnchanged returns 76827276. So I guess it is adding the unchanged values in the three dimensions? The values correspond to RGB values and my aim is to find the values that remain the same as the background that I started with.

[Matt J]

Yep, you never mentioned anything about these being RGB images, but the modification is easy

 [i,j]=find(all(A==B,3));

[Samadrita]

Sorry about not mentioning RGB! [i,j] is still a matrix bigger than my original matrix at 25609092x2 . I also tried simply find(all(A==B)),that is a 933X1 matrix. Would that give me the number of unchanged values? Or am I misunderstanding something? Thanks for commenting.

[Matt J]

[i,j] is still a matrix bigger than my original matrix at 25609092x2

No, I don't think it's bigger

    >> 5052*6492>25609092
    ans =
         1