DCDet: Dynamic Cross-based 3D Object Detector
Shuai Liu, Boyang Li, Zhiyu Fang, Kai Huang
TL;DR
DCDet tackles two core challenges in 3D object detection: imbalanced positive sampling across object scales and rotation-aware regression. It introduces Dynamic Cross Label Assignment (DCLA), which samples positives from a cross-shaped region around each ground-truth center using a cost-based top-$k$ selection and a scalable radius $r$, and Rotation-Weighted IoU (RWIoU), which integrates rotation and direction into the IoU to drive regression. Together, these yield a unified framework that achieves state-of-the-art or competitive performance on Waymo Open and KITTI, with notable data efficiency and improved performance for small objects. The approach highlights the importance of task-aligned label assignment and rotation-aware loss design for robust 3D detection in real-world scenarios.
Abstract
Recently, significant progress has been made in the research of 3D object detection. However, most prior studies have focused on the utilization of center-based or anchor-based label assignment schemes. Alternative label assignment strategies remain unexplored in 3D object detection. We find that the center-based label assignment often fails to generate sufficient positive samples for training, while the anchor-based label assignment tends to encounter an imbalanced issue when handling objects of varying scales. To solve these issues, we introduce a dynamic cross label assignment (DCLA) scheme, which dynamically assigns positive samples for each object from a cross-shaped region, thus providing sufficient and balanced positive samples for training. Furthermore, to address the challenge of accurately regressing objects with varying scales, we put forth a rotation-weighted Intersection over Union (RWIoU) metric to replace the widely used L1 metric in regression loss. Extensive experiments demonstrate the generality and effectiveness of our DCLA and RWIoU-based regression loss. The Code will be available at https://github.com/Say2L/DCDet.git.
