HeMoRa: Unsupervised Heuristic Consensus Sampling for Robust Point Cloud Registration

Heuristic information for consensus set sampling is essential for correspondence-based point cloud registration, but existing approaches typically rely on supervised learning or expert-driven parameter tuning. In this work, we propose HeMoRa, a new unsupervised framework that trains a Heuristic information Generator (HeGen) to estimate sampling probabilities for correspondences using a Multi-order Reward Aggregator (MoRa) loss. The core of MoRa is to train HeGen through extensive trials and feedback, enabling unsupervised learning. While this process can be implemented using policy optimization, directly applying the policy gradient to optimize HeGen presents challenges such as sensitivity to noise and low reward efficiency. To address these issues, we propose a Maximal Reward Propagation (MRP) mechanism that enhances the training process by prioritizing noise-free signals and improving reward utilization. Experimental results show that equipped with HeMoRa, the consensus set sampler achieves improvements in both robustness and accuracy. For example, on the 3DMatch dataset with FCGF feature, the registration recall of our unsupervised methods (Ours+SM and Ours+SC$^2$) even outperforms the state-of-the-art supervised method VBreg. Our code is available at \href{https://anonymous.4open.science/r/HeMoRa-CVPR/README.md}{\texttt{HeMoRa}}.