RoBiFusion: A Robust and Bidirectional Interaction Camera-LiDAR 3D Object Detection Framework

Camera-LiDAR 3D object detection is currently becoming a crucial component in the field of autonomous driving perception. However, previous models only performed feature fusion in the deep-level BEV hierarchy when dealing with camera-LiDAR feature fusion. This approach lacks interaction with the shallow-level sensor features, which is beneficial in constructing the corresponding BEV features. However, a simple shallow-level feature interaction can introduce sensor noise caused by intrinsic and extrinsic camera calibration errors. To address this, we propose RoBiFusion, a novel camera-LiDAR 3D object detection framework designed for effective sensor feature interaction and mitigating sensor noise interference. This framework consists of three submodules: the Camera-LiDAR Feature Matching module, the LiDAR-to-Camera module, and the Camera-to-LiDAR module. Firstly, in the Camera-LiDAR Feature Matching module, we use the cross-attention module to dynamically match the camera features and the LiDAR features, which solves the problem of feature inconsistency caused by noise in the camera's intrinsic and extrinsic parameters. Secondly, in the LiDAR-to-Camera module, we propose a novel depth representation that can effectively mitigate LiDAR noise interference. Thirdly, in the Camera-to-LiDAR module, we introduce deformable attention to help LiDAR feature capture instance-level semantic features. Additionally, we design a novel differentiable and efficient grid sample module to accelerate the process since the bilinear grid sample module in deformable attention is time-consuming and not deployment-friendly. We compared RoBiFusion to the state-of-the-art BEVFusion on the nuScenes dataset and found that RoBiFusion surpasses BEVFusion by 1.5% mAP and 2.4% NDS. Furthermore, we designed a series of ablation experiments to verify the effectiveness of the aforementioned modules.