How can I use a loop to subtract a pixel's gray level to it´s neighbor pixel's gray level?

How can I use a loop to subtract a pixel's gray level to it´s neighbor pixel's gray level?

Answer 1

[Thorsten]

 I = im2double(imread('cameraman.tif'));
 Ix = diff(I')';
 Iy = diff(I);

[Teemu]

how about the loop?

[Thorsten]

diff works on every pixel in the image so you do not need a loop. That's one of the major advantages of Matlab.

[Teemu]

That is a good function. thank you, that helps me a lot.

[Teemu]

Can I do diff function to one file to both x- and y-direction? Or can I make one file from Ix and Iy? I mean that I do diff function and get one file.

[Teemu]

Can I use diff function to subtract pixel from 2-pixel away from it? So it not neigbour pixel anymore.