This paper introduces data augmentation for point clouds by interpolation between examples. Data augmentation by interpolation has shown to be a simple and effective approach in the image domain. Such a mixup is however not directly transferable to point clouds, as we do not have a one-to-one correspondence between the points of two different objects. In this paper, we define data augmentation between point clouds as a shortest path linear interpolation. To that end, we introduce PointMixup, an interpolation method that generates new examples through an optimal assignment of the path function between two point clouds. We prove that our PointMixup finds the shortest path between two point clouds and that the interpolation is assignment invariant and linear. With the definition of interpolation, PointMixup allows to introduce strong interpolation-based regularizers such as mixup and manifold mixup to the point cloud domain. Experimentally, we show the potential of PointMixup for point cloud classification, especially when examples are scarce, as well as increased robustness to noise and geometric transformations to points. The code for PointMixup and the experimental details are publicly available.

本文提出利用插值增强点云的数据，定义了点云之间的最短路径线性插值，介绍了PointMixup方法进行插值，可以引入基于插值的正则化方法，例如mixup和manifold mixup，证明了PointMixup可以找到点云之间的最短路径，实验显示它能够显著提高点云分类的性能，特别是在数据不足以及噪声和几何变形的情况下。

PointMixup: 点云增强