oqtvs

@paroj and @StevenPuttemans aren't them different algorithms? #933 is https://en.wikipedia.org/wiki/Harris_affine_region_detector and the proposal here is https://en.wikipedia.org/wiki/Hessian_affine_region_detector

Also some note here that according this article: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.157.4126&rep=rep1&type=pdf these features can work together: > These methods typically provide complementary features to the > ones discussed in the previous chapter