PointCLIP V2: Prompting CLIP and GPT for Powerful 3D Open-world Learning

Large-scale pre-trained models have shown promising open-world performance for both vision and language tasks. However, their transferred capacity on 3D point clouds is still limited and only constrained to the classification task. In this paper, we first collaborate CLIP and GPT to be a unified 3D open-world learner, named as PointCLIP V2, which fully unleashes their potential for zero-shot 3D classification, segmentation, and detection. To better align 3D data with the pre-trained language knowledge, PointCLIP V2 contains two key designs. For the visual end, we prompt CLIP via a shape projection module to generate more realistic depth maps, narrowing the domain gap between projected point clouds with natural images. For the textual end, we prompt the GPT model to generate 3D-specific text as the input of CLIP's textual encoder. Without any training in 3D domains, our approach significantly surpasses PointCLIP by +42.90%, +40.44%, and +28.75% accuracy on three datasets for zero-shot 3D classification. On top of that, V2 can be extended to few-shot 3D classification, zero-shot 3D part segmentation, and 3D object detection in a simple manner, demonstrating our generalization ability for unified 3D open-world learning.

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Task Dataset Model Metric Name Metric Value Global Rank Uses Extra
Training Data
Result Benchmark
Zero-Shot Transfer 3D Point Cloud Classification ModelNet10 PointCLIP V2 Accuracy (%) 73.13 # 2
Training-free 3D Point Cloud Classification ModelNet40 PointCLIP V2 Accuracy (%) 64.2 # 2
Need 3D Data? No # 1
Zero-Shot Transfer 3D Point Cloud Classification ModelNet40 PointCLIP V2 Accuracy (%) 64.22 # 6
Zero-shot 3D Point Cloud Classification ScanNetV2 PointCLIP V2 Top 1 Accuracy % 11.0 # 7
Training-free 3D Point Cloud Classification ScanObjectNN PointCLIP V2 Accuracy (%) 35.4 # 2
Need 3D Data? No # 1
Zero-Shot Transfer 3D Point Cloud Classification ScanObjectNN PointCLIP V2 PB_T50_RS Accuracy (%) 35.36 # 1
OBJ_BG Accuracy(%) 41.22 # 1
OBJ_ONLY Accuracy(%) 50.09 # 5
Training-free 3D Part Segmentation ShapeNet-Part PointCLIP V2 mIoU 48.4 # 2
Need 3D Data? No # 1
3D Open-Vocabulary Instance Segmentation STPLS3D PointCLIPV2 AP50 03.1 # 2

Methods