Point Clouds Are Specialized Images: A Knowledge Transfer Approach for 3D Understanding

Publisher:
Institute of Electrical and Electronics Engineers (IEEE)
Publication Type:
Journal Article
Citation:
IEEE Transactions on Multimedia, 2024, PP, (99), pp. 1-11
Issue Date:
2024-01-01
Full metadata record
Self-supervised representation learning (SSRL) has gained increasing attention in point cloud understanding, in addressing the challenges posed by 3D data scarcity and high annotation costs. This paper presents PCExpert, a novel SSRL approach that reinterprets point clouds as “specialized images”. This conceptual shift allows PCExpert to leverage knowledge derived from large-scale image modality in a more direct and deeper manner, via extensively sharing the parameters with a pretrained image encoder in a multi-way Transformer architecture. The parameter sharing strategy, combined with an additional pretext task for pre-training, i.e., transformation estimation, empowers PCExpert to outperform the state of the arts in a variety of tasks, with a remarkable reduction in the number of trainable parameters. Notably, PCExpert's performance under LINEAR fine-tuning (e.g., yielding a 90.02% overall accuracy on ScanObjectNN) has already closely approximated the results obtained with FULL model fine-tuning (92.66%), demonstrating its effective representation capability.
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