We propose an octree guided neural network architecture and spherical
convolutional kernel for machine learning from arbitrary 3D point clouds. The
network architecture capitalizes on the sparse nature of irregular point
clouds, and hierarchically coarsens the data representation with space
partitioning. At the same time, the proposed spherical kernels systematically
quantize point neighborhoods to identify local geometric structures in the
data, while maintaining the properties of translation-invariance and asymmetry.
We specify spherical kernels with the help of network neurons that in turn are
associated with spatial locations. We exploit this association to avert dynamic
kernel generation during network training that enables efficient learning with
high resolution point clouds. The effectiveness of the proposed technique is
established on the benchmark tasks of 3D object classification and
segmentation, achieving new state-of-the-art on ShapeNet and RueMonge2014
datasets.

本文提出了一种基于八叉树引导的神经网络结构和球形卷积核来进行任意 3D 点云的机器学习。该网络架构充分利用了不规则点云的稀疏性，并通过空间划分分层粗化数据表示。同时，该提议的球形核有系统地量化点邻域，以识别数据中的局部几何结构，同时保持平移不变性和不对称性。我们利用与空间位置相关联的网络神经元来指定球形核，从而避免了网络训练期间动态核生成，以实现高分辨率点云的高效学习，并在 3D 对象分类和分割的基准任务上取得了新的最先进状态，分别在 ShapeNet 和 RueMonge2014 数据集上。