How to compare two 3D matrices element-wise?

Question

评论： Hadi Ghahremannezhad 2021-2-10

I have two RGB images (3D matrix: x, y, z) of the same size, and I wanted to compare the corresponding values.

Suppose there are two matrices A and B, both have size (4,5,3).

I want a 2D mask (logical image) that represents the (x,y) points where matrix A is less than matrix B in all 3 values of the third (z) dimension.

So for example the mask(4,4) = 1 if:

I tried this but it doesn't work, because the resulting matrix (ALessThanB) is 3D logical:

ALessThanB = A < B;

How can I make this comparison only along the third dimension?

Answer 1

Steven Lord 2021-2-10

Use the all function. You'll want to specify the optional dim input argument as well as the required A input argument (the data.)

thanks, all(A < B, 3) worked.