Geometric Correspondence Consistency in RGB-D Relative Pose Estimation.

Relative pose estimation for RGB-D cameras is crucial in a number of applications. A typical approach relies on RANSAC to find a triplet pair of 3D point correspondences from which relative pose can be derived. A key aspect to this work ensures the geometric consistency of the triplet, i.e., pairwise distances between 3D points are preserved between the two views. Observe, however, that depth values are typically an order of magnitude less precise than feature locations, leading to large distance thresholds and admission of numerous false positives. This paper proposes that the constraint of 3D distance can be cast as a 2D constraint which we refer to as the Geometric Correspondence Constraint (GCC). This constraint states that given one pair of correspondences, the two images are partitioned into a family nested of curves such that corresponding points must lie on corresponding curves. This can act as a filter in the RANSAC process with significant savings in computation and with increased robustness and accuracy as demonstrated in experiments using TUM, ICL-NUIM, and RGBD Scene v2 datasets.