Feature learning for 3D object detection from point clouds is very challenging due to the irregularity of 3D point cloud data. In this paper, we propose Pointformer, a Transformer backbone designed for 3D point clouds to learn features effectively. Specifically, a Local Transformer module is employed to model interactions among points in a local region, which learns context-dependent region features at an object level. A Global Transformer is designed to learn context-aware representations at the scene level. To further capture the dependencies among multi-scale representations, we propose Local-Global Transformer to integrate local features with global features from higher resolution. In addition, we introduce an efficient coordinate refinement module to shift down-sampled points closer to object centroids, which improves object proposal generation. We use Pointformer as the backbone for state-of-the-art object detection models and demonstrate significant improvements over original models on both indoor and outdoor datasets.

本文提出了一种3D点云特征学习模型Pointformer，其中使用局部和全局Transformer模块对点云数据进行建模，结合了多尺度特征，以及使用坐标调整模块改善物体提议生成，成功地应用于室内和室外场景下目标检测任务，并取得了显著的性能提升。

Pointformer进行的3D物体检测