Convert a 3D image array into a cell array

Hi,

I know this will be basic for an experienced Matlab user but what I'm trying to do is convert an image stack, say a [mxnXp] matrix where p is the indexing dimension into a [px1] cell array.

My motivation for doing this originally was because I wanted to check to see which 'frames' of my image array were blank, i.e. equal to zeros(m,n).

I tried to use something like the following:

indices = find(arrayfun(@(IDX) ~isequal(IDX), isequal(imstack, zeros(size(imstack,1),size(imstack,2)))));

however this didn't work since imstack is a 3D matrix (at least this is why I suspect it didn't work)

To remedy I thought to convert imstack to a px1 cell array, with the view to using a 'cellfun' version of the above. And this is where I got stuck converting imstack to a cell array.

Any suggestions would be appreciated.

Thank you.

n

Answer 1

[Razvan]

Try this:

blank = true(1,p);
for k = 1:p
  if any(M(:,:,k))
    blank(k) = false;
  end
end

where M is your 3d matrix and p is the number of frames. You'll get in the end a vector blank which is true for the blank frames. To get the indices do

find(blank)

[Nora]

This does the trick. Thanks for your help

Answer 2

[Matt J]

A more efficient approach than the for-loop would be

 blank=~any(reshape(M,[],p),1);

Also, to put the slices of an array into cells, you can use this FEX file

http://www.mathworks.com/matlabcentral/fileexchange/35085-split-nd-array-into-equal-sized-cells

In your case, this would look like

 Mcell=mat2tiles(M,[inf,inf,1]);
 Mcell=Mcell(:); %make px1