comp_gradient.m

this is a very very very nice code

%Computes the y and x gradients with a [-.5,0,.5] kernel
function [fy,fx] = comp_gradient(IM, type);

fy = zeros(size(IM));
fx = zeros(size(IM));
for y = 2:size(IM,1)-1
    for x = 2:size(IM,2)-1
        fy(y,x) = IM(y+1,x) - IM(y-1,x);
        fx(y,x) = IM(y,x+1) - IM(y,x-1);
    end
end
fy = fy / 2;
fx = fx / 2;