how to identify a 3d matrix?

by using the function:

MAT=imread('image.jpg');

sometimes (if the image isn't in grayscale) i get output of 3D matrix (RGB) is there any function or a technic i can use?

[Sara]

Can use to do what?

Answer 1

[the cyclist]

numel(size(MAT))>=3

will be true for an array of dimension 3 or greater.

Note that this will not discriminate between objects of dimension 1 and 2, because of how MATLAB stores scalars as vectors of length 1 (and therefore have size 1x1).

Answer 2

[Geoff Hayes]

Try ndims which returns the number of dimensions

 if ndims(MAT)==3
    % matrix is three dimensional
 end

[the cyclist]

I didn't know about this command, which is a cleaner version of what I did more manually. Note that it suffers from the same weakness about not being able to discriminate between objects of dimension 1 and 2.

[Geoff Hayes]

That's true. You could use isvector to discriminate between objections of dimension 1 and 2.

I suppose even ismatrix could be used to determine if the object has at most two dimensions (and so ~ismatrix(MAT) would be true for a 3D image).