Abstract
Geometric deep learning is increasingly important
thanks to the popularity of 3D sensors. Inspired by
the recent advances in NLP domain, the self-attention
transformer is introduced to consume the point clouds.
We develop Point Attention Transformers (PATs), using a
parameter-efficient Group Shuffle Attention (GSA) to replace the costly Multi-Head Attention. We demonstrate its
ability to process size-varying inputs, and prove its permutation equivariance. Besides, prior work uses heuristics dependence on the input data (e.g., Furthest Point Sampling)
to hierarchically select subsets of input points. Thereby, we
for the first time propose an end-to-end learnable and taskagnostic sampling operation, named Gumbel Subset Sampling (GSS), to select a representative subset of input points.
Equipped with Gumbel-Softmax, it produces a ”soft” continuous subset in training phase, and a ”hard” discrete subset in test phase. By selecting representative subsets in a
hierarchical fashion, the networks learn a stronger representation of the input sets with lower computation cost. Experiments on classification and segmentation benchmarks
show the effectiveness and efficiency of our methods. Furthermore, we propose a novel application, to process event
camera stream as point clouds, and achieve a state-of-theart performance on DVS128 Gesture Dataset.