Inverse/opposite of diff function?

I have a 480x640 matrix and would like to perform the diff function on the elements but instead of subtracting the previous element I would like to add it.

I have tried using x(2:end) + x(1:end-1) Which return the right values but instead of returning a 479x640 matrix it returns a 1x307199 matrix. How can I change the function to give the 479x640 matrix.

Thanks in advance

Answer 1

[Torsten]

x(1:end-1,:) + x(2:end,:)

Best wishes

Torsten.

[Gregor Lees]

thank you

Answer 2

[Kristopher Anderson]

The opposite of diff is cumsum.

Example:

    >> A = randi([1,5],1,5)

    A =

         1     3     5     2     1

    >> B = diff(A)

    B =

         2     2    -3    -1

    >> C = cumsum([A(1) B])

    C =

         1     3     5     2     1