Papers › Unleashing HyDRa: Hybrid Fusion, Depth Consistency and Radar for Unified 3D Perception

Unleashing HyDRa: Hybrid Fusion, Depth Consistency and Radar for Unified 3D Perception

12 Mar 2024arXiv:2403.07746archive 2025-07-28

Philipp Wolters, Johannes Gilg, Torben Teepe, Fabian Herzog, Anouar Laouichi, Martin Hofmann, Gerhard Rigoll

Low-cost, vision-centric 3D perception systems for autonomous driving have made significant progress in recent years, narrowing the gap to expensive LiDAR-based methods. The primary challenge in becoming a fully reliable alternative lies in robust depth prediction capabilities, as camera-based systems struggle with long detection ranges and adverse lighting and weather conditions. In this work, we introduce HyDRa, a novel camera-radar fusion architecture for diverse 3D perception tasks. Building upon the principles of dense BEV (Bird's Eye View)-based architectures, HyDRa introduces a hybrid fusion approach to combine the strengths of complementary camera and radar features in two distinct representation spaces. Our Height Association Transformer module leverages radar features already in the perspective view to produce more robust and accurate depth predictions. In the BEV, we refine the initial sparse representation by a Radar-weighted Depth Consistency. HyDRa achieves a new state-of-the-art for camera-radar fusion of 64.2 NDS (+1.8) and 58.4 AMOTA (+1.5) on the public nuScenes dataset. Moreover, our new semantically rich and spatially accurate BEV features can be directly converted into a powerful occupancy representation, beating all previous camera-based methods on the Occ3D benchmark by an impressive 3.7 mIoU. Code and models are available at https://github.com/phi-wol/hydra.

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Code

phi-wol/hydra officialmentioned in papermentioned on GitHubpytorch report

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Tasks

3D Multi-Object Tracking3D Object Detection3D Object Detection (RoI)3D Semantic Occupancy PredictionAutonomous DrivingDepth PredictionPrediction Of Occupancy Grid Maps

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
3D Multi-Object Tracking nuScenes HyDRa AMOTA 0.584 #58 of 115 Archive leaderboard report
3D Multi-Object Tracking nuscenes Camera-Radar HyDRa AMOTA 0.584 #2 of 4 Archive leaderboard report
3D Object Detection TruckScenes HyDRa NDS 22.4 #2 of 4 Archive leaderboard report
3D Object Detection TruckScenes HyDRa mAP 12.8 #2 of 4 Archive leaderboard report
3D Object Detection View-of-Delft (val) HyDRa mAP 60.9 #1 of 11 Archive leaderboard report
3D Object Detection nuScenes HyDRa NDS 0.64 #139 of 372 Archive leaderboard report
3D Object Detection nuScenes HyDRa mAAE 0.12 #139 of 372 Archive leaderboard report
3D Object Detection nuScenes HyDRa mAOE 0.42 #139 of 372 Archive leaderboard report
3D Object Detection nuScenes HyDRa mAP 0.57 #139 of 372 Archive leaderboard report
3D Object Detection nuScenes HyDRa mASE 0.25 #139 of 372 Archive leaderboard report
3D Object Detection nuScenes HyDRa mATE 0.40 #139 of 372 Archive leaderboard report
3D Object Detection nuScenes HyDRa mAVE 0.25 #139 of 372 Archive leaderboard report
3D Object Detection nuscenes Camera-Radar HyDRa NDS 64.2 #3 of 11 Archive leaderboard report
Prediction Of Occupancy Grid Maps Occ3D-nuScenes HyDRa R50 mIoU 44.4 #5 of 8 Archive leaderboard report

Ranks are positions in the archive's leaderboards as they stood at the 2025-07-28 snapshot. Results published since then are not among these rows, so a rank here is not a current standing.

Methods

Absolute Position EncodingsAdamAttentionBPEDense ConnectionsDropoutHydraLabel SmoothingLayer NormalizationLinear LayerMulti-Head AttentionPosition-Wise Feed-Forward LayerResidual ConnectionSoftmaxTransformer

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