Abstract
Analyzing the geometric and semantic properties of 3D
point clouds through the deep networks is still challenging
due to the irregularity and sparsity of samplings of their geometric structures. This paper presents a new method to
define and compute convolution directly on 3D point clouds
by the proposed annular convolution. This new convolution operator can better capture the local neighborhood
geometry of each point by specifying the (regular and dilated) ring-shaped structures and directions in the computation. It can adapt to the geometric variability and scalability at the signal processing level. We apply it to the
developed hierarchical neural networks for object classi-
fication, part segmentation, and semantic segmentation in
large-scale scenes. The extensive experiments and comparisons demonstrate that our approach outperforms the
state-of-the-art methods on a variety of standard benchmark datasets (e.g., ModelNet10, ModelNet40, ShapeNetpart, S3DIS, and ScanNet).