RSPReg: Reliability-aware Structural Prototype Learning for Point Cloud Registration

Point cloud registration remains challenging in scenarios with low overlap, repetitive structures, and local geometric ambiguities, where candidate correspondences established based on local geometric similarity often lack global structural consistency and are prone to unreliable matches. To address this issue, this paper proposes RSPReg, a reliability-aware structural prototype learning framework for robust point cloud registration. RSPReg learns structural prototypes from rotation-invariant coarse-level superpoint features to characterize the structural attributes of local regions within the entire point cloud. These prototypes are further introduced as structural priors into cross-cloud correspondence reasoning, thereby improving the structural consistency of candidate correspondences. Furthermore, RSPReg estimates the uncertainty of structural prototypes and adaptively modulates the role of structural priors in the matching and pose estimation processes, reducing the negative impact of ambiguous and non-overlapping regions on registration results. Experiments on 3DMatch, 3DLoMatch, KITTI, and ETH demonstrate that RSPReg achieves the highest registration recall and exhibits clear advantages in low-overlap and cross-domain scenarios.