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L2RSI: Cross-view LiDAR-based Place Recognition for Large-scale Urban Scenes via Remote Sensing Imagery
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Builds LiRSI-XA dataset and L2RSI, which aligns LiDAR BEV submaps with remote-sensing semantic submaps via contrastive learning and refines retrieval with Gaussian-mixture spatio-temporal particle estimation (STPE) for large-scale cross-view LiDAR place recognition.
Problem
LiDAR-based place recognition normally needs costly prior 3D maps; using overhead remote sensing imagery as the reference creates cross-view and cross-modal gaps, and single queries are ambiguous over a 100 km^2 area.
Approach
Map LiDAR submaps and remote-sensing submaps into a shared semantic space (segmentation labels, MAE-based dual-branch encoder with symmetric InfoNCE), then aggregate retrieval results from a sequence of queries as a mixture of Gaussians propagated by odometry, instead of particle filtering that discards particles.
Key results
- On LiRSI-XA Test Set-G (100 km^2, 63k RSI database), L2RSI (w. STPE) reaches Recall@1 of 83.27% and Recall@10 of 87.82% at a 30 m threshold, versus 22.95% for Sample4Geo.
- Without any fine-tuning, L2RSI (w. STPE) reaches Recall@1 above 40% on both LiRSI-Oxford trajectories, while baselines such as LIP-Loc and GeoDTR stay near 1% Recall@1.
- STPE adds about 31.7 ms per query (sampling rate 30%), and the total of 37.5 ms allows real-time operation.
Measured effects reported in the paper
| What was changed | Where | Measured | Effect |
|---|---|---|---|
| Use L2RSI with STPE instead of Sample4Geo | LiRSI-XA and LiRSI-Oxford place recognition · LiRSI-XA Test Set-G (100km²) | Recall@1 (%): 22.95 -> 83.27 | Helped |
| Add semantic segmentation (ablation) | L2RSI · LiRSI-XA Test Set-S | Recall@1 (%): 50.43 -> 88.93 | Helped |
| Add semantic segmentation (ablation) | L2RSI · LiRSI-Oxford 11-14-02-26 | Recall@1 (%): 8.13 -> 42.29 | Helped |
| Add STPE (ablation) | L2RSI · LiRSI-XA Test Set-S | Recall@1 (%): 30.05 -> 88.93 | Helped |
| Add STPE (ablation) | L2RSI · LiRSI-Oxford 11-14-02-26 | Recall@1 (%): 10.19 -> 42.29 | Helped |
| Add orientation input (ablation) | L2RSI · LiRSI-XA Test Set-S | Recall@1 (%): 54.37 -> 88.93 | Helped |
| Add orientation input (ablation) | L2RSI · LiRSI-Oxford 11-14-02-26 | Recall@1 (%): 4.92 -> 42.29 | Helped |
| Use MAE-B rather than the other evaluated semantic encoders (ablation) | L2RSI · LiRSI-XA Test Set-S | Recall@1 (%): 73.77; 59.38; 72.58; 83.75; 84.72 -> 88.93 | Helped |
| Set STPE sampling rate λ to 30% rather than the other tested rates (ablation) | L2RSI · LiRSI-XA Test Set-S | Recall@1 (%): 85.98; 88.07; 88.93; 88.44; 88.44; 88.07; 88.07; 87.82; 88.07; 88.44 | Mixed |
| Increase yaw and translation noise in the STPE motion model (ablation) | L2RSI STPE · LiRSI-XA Test Set-G (100km²) | Recall@1 (%): 83.27(-0.00) -> 35.91(-47.36) | Hurt |
Surprising findings
- Replacing particle filtering with the proposed aggregation is needed because particles decay under unreliable single queries; PF reached only 47.85% Recall@1 on Test Set-G versus 83.27% for STPE.
- DINOv2-S gave strong results on Test Set-S and Test Set-G but collapsed to 1.40% Recall@1 on the Oxford trajectory, unlike MAE-B.
Limitations
- Requires an external magnetometer for directional reference (about ±10 degrees accuracy).
- Designed for urban scenes; performance may degrade in rural areas with sparse semantics.
- Temporal gap of three years between LiDAR and remote sensing imagery causes failures due to changed structures.
Experimental setup
Datasets: LiRSI-XA LiRSI-Oxford LiRSI-Kitti360 SemanticKITTI KITTI-360 Oxford Radar RobotCar
Benchmarks: LiRSI-XA LiRSI-Oxford LiRSI-Kitti360
Metrics: Recall@1 Recall@10 Recall@30 runtime (ms) parameters (M)
Baselines: LIP-Loc GeoDTR Sample4Geo FRGeo SuperGlobal particle filtering
Builds on: MAE InfoNCE SphereFormer FastGICP SuperGlobal
Closest papers by meaning
- HOTFormerLoc: Hierarchical Octree Transformer for Versatile Lidar Place Recognition Across Ground and Aerial Views (CVPR 2025 · similarity 0.88)
- ForestLPR: LiDAR Place Recognition in Forests Attentioning Multiple BEV Density Images (CVPR 2025 · similarity 0.87)
- LiSA: LiDAR Localization with Semantic Awareness (CVPR 2024 · similarity 0.86)
- Multi-Modal Aerial-Ground Cross-View Place Recognition with Neural ODEs (CVPR 2025 · similarity 0.85)
- From Coarse to Fine: A Matching and Alignment Framework for Unsupervised Cross-View Geo-Localization (AAAI 2025 · similarity 0.85)
- LightLoc: Learning Outdoor LiDAR Localization at Light Speed (CVPR 2025 · similarity 0.85)
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