Second-Order Difference

How can I find the Second-Order Difference signals in diagonal and minor diagonal of a matrix? The matrix is an image. For the horizontal and vertical I suppose this:

Dh = diff(image, 2);

Dv = diff(Image, 2 ,2);

Thanks!

Answer 1

[bym]

m = magic(4)
Dd = diff(diag(m),2) %diagonal
Dm = diff(diag(rot90(m)),2) %minor diagonal

[Bruno Bertini]

Thank you very much!

Dh and Dv are correct?

I have to use the Second-Order Difference signals for an image.

[bym]

Dh and Dv look correct. I have edited Dm to add the 2 ;)