MATLAB: ??? Index exceeds matrix dimensions.

Question

I think I have a problem with my matrices but I can't figure out where to fix it. The code that I have written is:

??? Index exceeds matrix dimensions.

Error in ==> dctwatermark at 75 dct_block=dct2(cover_object(y:y+blocksize-1,x:x+blocksize-1));

Answer 1

I speculate that your cover_object is not a multiple of blocksize in one (or both) directions, and your code only testing whether the x or y starts in the object instead of testing whether the end would also be in the object.