Wasserstein distance (WD) and the associated optimal transport plan have been proven useful in many applications where probability measures are at stake. In this paper, we propose a new proxy of the squared WD, coined min-SWGG, that is based on the transport map induced by an optimal one-dimensional projection of the two input distributions. We draw connections between min-SWGG and Wasserstein generalized geodesics in which the pivot measure is supported on a line. We notably provide a new closed form for the exact Wasserstein distance in the particular case of one of the distributions supported on a line allowing us to derive a fast computational scheme that is amenable to gradient descent optimization. We show that min-SWGG is an upper bound of WD and that it has a complexity similar to as Sliced-Wasserstein, with the additional feature of providing an associated transport plan. We also investigate some theoretical properties such as metricity, weak convergence, computational and topological properties. Empirical evidences support the benefits of min-SWGG in various contexts, from gradient flows, shape matching and image colorization, among others.

本文提出了一种新的WD代理min-SWGG，该代理基于两个输入分布的一维最优投影诱导的运输映射，并提供了一个相关的传输计划，证明min-SWGG是WD的上界且具有类似于切片Wasserstein的复杂度和梯度下降优化。作者也研究了一些理论性质和在渐进流、形状匹配和图像着色等各种情况下的实证支持。

通过切片Wasserstein广义测地线实现快速的最优输运