A Pseudo-Point-Based Adaptive Fusion Network for Multi-Modal 3D Detection

A 3D multi-modal detection method using a monocular camera and LiDAR has drawn much attention due to its low cost and strong applicability, making it highly valuable for autonomous driving and unmanned aerial vehicles (UAVs). However, conventional fusion approaches relying on static arithmetic operations often fail to adapt to dynamic, complex scenarios. Furthermore, existing ROI alignment techniques, such as local projection and cross-attention, are inadequate for mitigating the feature misalignment triggered by depth estimation noise in pseudo-point clouds. To address these issues, this paper proposes a pseudo-point-based 3D object detection method that achieves biased fusion of multi-modal data. First, a meta-weight fusion module dynamically generates fusion weights based on global context, adaptively balancing the contributions of point clouds and images. Second, a module combining bidirectional cross-attention and a gating filter mechanism is introduced to eliminate the ROI feature misalignment caused by depth completion noise. Finally, a class-agnostic box fusion strategy is introduced to aggregate highly overlapping detection boxes at the decision level, improving localization accuracy. Experiments on the KITTI dataset show that the proposed method achieves APs of 92.22%, 85.03%, and 82.25% on Easy, Moderate, and Hard difficulty levels, respectively, demonstrating leading performance. Ablation studies further validate the effectiveness and computational efficiency of each module.