PVNAS: 3D Neural Architecture Search with Point-Voxel Convolution

Zhijian Liu*, Haotian Tang*, Shengyu Zhao, Kevin Shao, Song Han
Massachusetts Institute of Technology (MIT)
(* indicates equal contributions)

Abstract

3D neural networks are widely used in real-world applications (e.g., AR/VR headsets, self-driving cars). They are required to be fast and accurate; however, limited hardware resources on edge devices make these requirements rather challenging. Previous work processes 3D data using either voxel-based or point-based neural networks, but both types of 3D models are not hardware-efficient due to the large memory footprint and random memory access. In this paper, we study 3D deep learning from the efficiency perspective. We first systematically analyze the bottlenecks of previous 3D methods. We then combine the best from point-based and voxel-based models together and propose a novel hardware-efficient 3D primitive, Point-Voxel Convolution (PVConv). We further enhance this primitive with the sparse convolution to make it more effective in processing large (outdoor) scenes. Based on our designed 3D primitive, we introduce 3D Neural Architecture Search (3D-NAS) to explore the best 3D network architecture given a resource constraint. We evaluate our proposed method on six representative benchmark datasets, achieving state-of-the-art performance with 1.8-23.7x measured speedup. Furthermore, our method has been deployed to the autonomous racing vehicle of MIT Driverless, achieving larger detection range, higher accuracy and lower latency.

Citation

@article{liu2021pvnas,
  title={PVNAS: 3D Neural Architecture Search with Point-Voxel Convolution},
  author={Liu, Zhijian and Tang, Haotian and Zhao, Shengyu and Shao, Kevin and Han, Song},
  journal={IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI)},
  year={2021}
}

Acknowledgments: This work is supported by NSF CAREER Award #1943349, MIT Quest for Intelligence, MIT-IBM Watson AI Lab, Samsung, Hyundai and SONY. We thank AWS Machine Learning Research Awards for providing the computational resource.