Surfel-Based Dense RGB-D Reconstruction With Global And Local Consistency

Achieving high surface reconstruction accuracy in dense mapping has been a desirable target for both robotics and vision communities. In the robotics literature, simultaneous localization and mapping (SLAM) systems use RGB-D cameras to reconstruct a dense map of the environment. They leverage the depth input to provide accurate local pose estimation and a locally consistent model. However, drift in the pose tracking over time leads to misalignments and artifacts. On the other hand, offline computer vision methods, such as the pipeline that combines structure-from-motion (SfM) and multi-view stereo (MVS), estimate the camera poses by performing batch optimization. These methods achieve global consistency, but suffer from heavy computation loads. We propose a novel approach that integrates both methods to achieve locally and globally consistent reconstruction. First, we estimate poses of keyframes in the offline SfM pipeline to provide strong global constraints at relatively low cost. Afterwards, we compute odometry between frames driven by off-the-shelf SLAM systems with high local accuracy. We fuse the two pose estimations using factor graph optimization to generate accurate camera poses for dense reconstruction. Experiments on real-world and synthetic datasets demonstrate that our approach produces more accurate models comparing to existing dense SLAM systems, while achieving significant speedup with respect to state-of-the-art SfM-MVS pipelines.