HOG

Hello, I am new to the scikit-image, and interested in using HOG. However, the one which is implemented doesn't seem to give as good results as expected. As a possible explanation I think mainly of 2 reasons: 1) the way of computing the gradients ( if I'm not mistaking, you use a [-1, 1] filter when they use a centered one [-1, 0, 1]. 2) They use tri-linear interpolation when here the you seem to use hard binning. Does this make sense or am I missing something? Also, I tried to write another version, trying to stick as much as possible to Dalal&Triggs version, although I don't really know how to assess the results it produces. Would that be of interest? Cheers, Jean