论文标题
用生成条件可逆流网络代表点云
Representing Point Clouds with Generative Conditional Invertible Flow Networks
论文作者
论文摘要
在本文中,我们提出了一种简单而有效的方法,将点云表示为从云特异性概率分布中绘制的样本集。这种解释与点云的内在特征相匹配:云中的点及其排序并不重要,因为所有点都是从对象边界的接近度中得出的。我们假设将每个云表示为由生成神经网络定义的参数化概率分布。一旦受过训练,这种模型就为点云操作操作提供了自然框架,例如将新云整合为默认的空间方向。为了利用同类对象之间的相似性并提高模型性能,我们转向权重共享:模拟同一家族中属于对象的点的点密度的网络共享所有参数,除了一个小的,特定于对象的嵌入向量外。我们表明,这些嵌入向量捕获对象之间的语义关系。我们的方法利用生成可逆流网络学习嵌入以及生成点云。由于这种表述并与类似的方法相反,我们能够以端到端的方式训练我们的模型。结果,我们的模型在基准数据集上提供了竞争性或卓越的定量结果,同时使前所未有的功能能够通过生成网络执行云操作任务,例如点云注册和再生。
In this paper, we propose a simple yet effective method to represent point clouds as sets of samples drawn from a cloud-specific probability distribution. This interpretation matches intrinsic characteristics of point clouds: the number of points and their ordering within a cloud is not important as all points are drawn from the proximity of the object boundary. We postulate to represent each cloud as a parameterized probability distribution defined by a generative neural network. Once trained, such a model provides a natural framework for point cloud manipulation operations, such as aligning a new cloud into a default spatial orientation. To exploit similarities between same-class objects and to improve model performance, we turn to weight sharing: networks that model densities of points belonging to objects in the same family share all parameters with the exception of a small, object-specific embedding vector. We show that these embedding vectors capture semantic relationships between objects. Our method leverages generative invertible flow networks to learn embeddings as well as to generate point clouds. Thanks to this formulation and contrary to similar approaches, we are able to train our model in an end-to-end fashion. As a result, our model offers competitive or superior quantitative results on benchmark datasets, while enabling unprecedented capabilities to perform cloud manipulation tasks, such as point cloud registration and regeneration, by a generative network.