Optimizing the Viewing Graph for Structure-from-Motion

The viewing graph represents a set of views that are re-lated by pairwise relative geometries. In the context of Structure-from-Motion (SfM), the viewing graph is the in-put to the incremental or global estimation pipeline. Much effort has been put towards developing robust algorithms to overcome potentially inaccurate relative geometries in the viewing graph during SfM. In this paper, we take a fun-damentally different approach to SfM and instead focus on improving the quality of the viewing graph before apply-ing SfM. Our main contribution is a novel optimization that improves the quality of the relative geometries in the view-ing graph by enforcing loop consistency constraints with the epipolar point transfer. We show that this optimization greatly improves the accuracy of relative poses in the view-ing graph and removes the need for filtering steps or robust algorithms typically used in global SfM methods. In addi-tion, the optimized viewing graph can be used to efficiently calibrate cameras at scale. We combine our viewing graph optimization and focal length calibration into a global SfM pipeline that is more efficient than existing approaches. To our knowledge, ours is the first global SfM pipeline capable of handling uncalibrated image sets. 1