Contextual descriptors improving credibility of keypoint matching: Harris-Affine, Hessian-Affme and SIFT feasibility study

The paper proposes CONSIFT descriptors which are the rotation-variant modification of SIFT (primarily for affine-invariant keypoints). CONSIFT of a keypoint K is its SIFT computed relatively to the orientation defined by the location of another keypoint L (and concatenated with similarly computed SIFT for keypoint L relatively to the location of K). It is additionally recommended that K and L are extracted by different detectors of complementary properties (e.g. Harris-Affine and Hessian-Affine). The paper evaluates CONSIFT performances over the benchmark dataset. Surprisingly, performances of CONSIFT are nearly equivalent to SIFT. However, the intersection of SIFT-based and CONSIFT-based matches is a highly discriminative tool which rejects most of correspondences which are incorrect in a wider context. Since the method does not require any consistency verification over groups of preliminary matched keypoints (and its memory usage is acceptable) it can be instrumental in large-scale CBVIR systems.