Robust Monocular Edge Visual Odometry through Coarse-to-Fine Data Association

This work describes a monocular visual odometry framework, which exploits the best attributes of edge features for illumination-robust camera tracking, while at the same time ameliorating the performance degradation of edge mapping. In the front-end, an ICP-based edge registration provides robust motion estimation and coarse data association under lighting changes. In the back-end, a novel edge-guided data association pipeline searches for the best photometrically matched points along geometrically possible edges through template matching, so that the matches can be further refined in later bundle adjustment. The core of our proposed data association strategy lies in a point-to-edge geometric uncertainty analysis, which analytically derives (1) a probabilistic search length formula that significantly reduces the search space and (2) a geometric confidence metric for mapping degradation detection based on the predicted depth uncertainty. Moreover, a match confidence based patch size adaption strategy is integrated into our pipeline to reduce matching ambiguity. We present extensive analysis and evaluation of our proposed system on synthetic and real- world benchmark datasets under the influence of illumination changes and large camera motions, where our proposed system outperforms current state-of-art algorithms.