For the sticks kernel generation each entry is either 0 or 1/(n x k) where n is stick length and k is thickness so at sticks.m file line 22 ' s0 = 1/n;' has to be updated to s0 = 1/(n*k); to use the sticks filter thickness (k) for the filter generation. Otherwise, the algorithm generates convolution values above uint8 and G = uint8(round(G)); at sf.m line 48 will round to max(uint8).