Wednesday, October 21, 2009

Lab Meeting 10/28 (Any): GroupSAC

Kai Ni, Hailin Jin, and Frank Dellaert. GroupSAC: Efficient Consensus in the Presence of Groupings. In International Conference on Computer Vision (ICCV), September 2009.

Abstract--We present a novel variant of the RANSAC algorithmthat is much more efficient, in particular when dealing with problems with low inlier ratios. Our algorithm assumes that there exists some grouping in the data, based on which we introduce a new binomial mixture model rather than the simple binomial model as used in RANSAC. We prove that in the new model it is more efficient to sample data from a smaller numbers of groups and groups with more tentative correspondences, which leads to a new sampling procedure that uses progressive numbers of groups. We demonstrate our algorithm on two classical geometric vision problems: wide-baseline matching and camera resectioning. The experiments show that the algorithm servesas a general framework that works well with three possible grouping strategies investigated in this paper, including a novel optical flow based clustering approach. The results show that our algorithm is able to achieve a significant performance gain compared to the standard RANSAC and PROSAC.


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