Imitation Learning from Observation (ILfO) is a setting in which a learner
tries to imitate the behavior of an expert, using only observational data and
without the direct guidance of demonstrated actions. In this paper, we
re-examine the use of optimal transport for IL, in which a reward is generated
based on the Wasserstein distance between the state trajectories of the learner
and expert. We show that existing methods can be simplified to generate a
reward function without requiring learned models or adversarial learning.
Unlike many other state-of-the-art methods, our approach can be integrated with
any RL algorithm, and is amenable to ILfO. We demonstrate the effectiveness of
this simple approach on a variety of continuous control tasks and find that it
surpasses the state of the art in the IlfO setting, achieving expert-level
performance across a range of evaluation domains even when observing only a
single expert trajectory without actions.

实时观察下的模仿学习 (ILfO) 中，利用最优传输来生成奖励函数，通过状态轨迹的 Wasserstein 距离衡量学习者和专家之间的差异，无需学习模型或对抗学习，可以与任何强化学习算法集成，并适用于 ILfO，能在多个连续控制任务中超越现有方法，在单个专家轨迹无动作观测的情况下实现专家级性能。