Imitation from Observations with Trajectory-Level Generative Embeddings

Fuente: arXiv
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Main Authors: Qu, Yongtao, Li, Shangzhe, Zhang, Weitong
Format: Preprint
Published: 2026
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author Qu, Yongtao
Li, Shangzhe
Zhang, Weitong
author_facet Qu, Yongtao
Li, Shangzhe
Zhang, Weitong
contents We consider the offline imitation learning from observations (LfO) where the expert demonstrations are scarce and the available offline suboptimal data are far from the expert behavior. Many existing distribution-matching approaches struggle in this regime because they impose strict support constraints and rely on brittle one-step models, making it hard to extract useful signal from imperfect data. To tackle this challenge, we propose TGE, a trajectory-level generative embedding for offline LfO that constructs a dense, smooth surrogate reward by estimating expert state density in the latent space of a temporal diffusion model trained on offline trajectory data. By leveraging the smooth geometry of the learned diffusion embedding, TGE captures long-horizon temporal dynamics and effectively bridges the gap between disjoint supports, ensuring a robust learning signal even when offline data is distributionally distinct from the expert. Empirically, the proposed approach consistently matches or outperforms prior offline LfO methods across a range of D4RL locomotion and manipulation benchmarks.
format Preprint
id arxiv_https___arxiv_org_abs_2601_00452
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Imitation from Observations with Trajectory-Level Generative Embeddings
Qu, Yongtao
Li, Shangzhe
Zhang, Weitong
Machine Learning
We consider the offline imitation learning from observations (LfO) where the expert demonstrations are scarce and the available offline suboptimal data are far from the expert behavior. Many existing distribution-matching approaches struggle in this regime because they impose strict support constraints and rely on brittle one-step models, making it hard to extract useful signal from imperfect data. To tackle this challenge, we propose TGE, a trajectory-level generative embedding for offline LfO that constructs a dense, smooth surrogate reward by estimating expert state density in the latent space of a temporal diffusion model trained on offline trajectory data. By leveraging the smooth geometry of the learned diffusion embedding, TGE captures long-horizon temporal dynamics and effectively bridges the gap between disjoint supports, ensuring a robust learning signal even when offline data is distributionally distinct from the expert. Empirically, the proposed approach consistently matches or outperforms prior offline LfO methods across a range of D4RL locomotion and manipulation benchmarks.
title Imitation from Observations with Trajectory-Level Generative Embeddings
topic Machine Learning
url https://arxiv.org/abs/2601.00452