Test-Time Augmentation for 3D Point Cloud Classification and Segmentation
This work addresses performance issues in 3D deep learning for sparse point clouds, offering an incremental improvement to existing methods.
The paper tackled the problem of performance drop in 3D point cloud tasks due to sparse data by exploring test-time augmentation using implicit field reconstruction and point cloud upsampling, showing that upsampling leads to more significant accuracy improvements on classification and segmentation tasks across multiple datasets.
Data augmentation is a powerful technique to enhance the performance of a deep learning task but has received less attention in 3D deep learning. It is well known that when 3D shapes are sparsely represented with low point density, the performance of the downstream tasks drops significantly. This work explores test-time augmentation (TTA) for 3D point clouds. We are inspired by the recent revolution of learning implicit representation and point cloud upsampling, which can produce high-quality 3D surface reconstruction and proximity-to-surface, respectively. Our idea is to leverage the implicit field reconstruction or point cloud upsampling techniques as a systematic way to augment point cloud data. Mainly, we test both strategies by sampling points from the reconstructed results and using the sampled point cloud as test-time augmented data. We show that both strategies are effective in improving accuracy. We observed that point cloud upsampling for test-time augmentation can lead to more significant performance improvement on downstream tasks such as object classification and segmentation on the ModelNet40, ShapeNet, ScanObjectNN, and SemanticKITTI datasets, especially for sparse point clouds.