Horizontal First Differencer on a Matrix

I have a matrix M and I need to implement a first differencer along the horizontal dimension as follows such that the value of each element is replaced by:

y[n, m] = x[n, m] − x[n, m − 1]

Where n and m be the independent variables (integer indices) indexing the matrix elements along the vertical and horizontal dimensions, respectively.

Answer 1

[Bjorn Gustavsson]

Have a look on the help and documentation to diff. For this case use:

y = diff(x,[],2);
% or explicitly 1st difference:
y = diff(x,1,2);
% or manually:
y = x(:,2:end) - y(:,1:end-1);

HTH

[Sarah Maas]

Thank you. Can you also tell me how i can derive the frequency response of the above?