无监督多模态融合：视觉/IMU/激光雷达互监督，免标注实现厘米级定位

TL;DR - This overview describes label-free fusion of cameras, IMUs, and LiDAR for robust centimeter-level localization in robotics and autonomous driving. Cross-sensor supervision could reduce annotation costs while improving resilience when individual sensors degrade.

• LiDAR geometry can supervise visual depth, while IMU measurements constrain long-term visual/LiDAR odometry drift.
• Self-supervised losses and cross-modal contrastive learning align 2D images with 3D point-cloud features without ground truth.
• Tightly coupled factor graphs or extended Kalman filters combine complementary sensor observations for higher accuracy and robustness.
• Remaining challenges include dynamic or degenerate environments, real-time computation, sensor failures, and cross-scene generalization.