DiffusionOPD: A Unified Perspective of On-Policy Distillation in Diffusion Models

Fuente: arXiv
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Autori principali: Li, Quanhao, Yu, Junqiu, Jiang, Kaixun, Wei, Yujie, Xing, Zhen, Li, Pandeng, Chu, Ruihang, Zhang, Shiwei, Liu, Yu, Wu, Zuxuan
Natura: Preprint
Pubblicazione: 2026
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author Li, Quanhao
Yu, Junqiu
Jiang, Kaixun
Wei, Yujie
Xing, Zhen
Li, Pandeng
Chu, Ruihang
Zhang, Shiwei
Liu, Yu
Wu, Zuxuan
author_facet Li, Quanhao
Yu, Junqiu
Jiang, Kaixun
Wei, Yujie
Xing, Zhen
Li, Pandeng
Chu, Ruihang
Zhang, Shiwei
Liu, Yu
Wu, Zuxuan
contents Reinforcement learning has emerged as a powerful tool for improving diffusion-based text-to-image models, but existing methods are largely limited to single-task optimization. Extending RL to multiple tasks is challenging: joint optimization suffers from cross-task interference and imbalance, while cascade RL is cumbersome and prone to catastrophic forgetting. We propose DiffusionOPD, a new multi-task training paradigm for diffusion models based on Online Policy Distillation (OPD). DiffusionOPD first trains task-specific teachers independently, then distills their capabilities into a unified student along the student own rollout trajectories. This decouples single-task exploration from multi-task integration and avoids the optimization burden of solving all tasks jointly from scratch. Theoretically, we lift the OPD framework from discrete tokens to continuous-state Markov processes, deriving a closed-form per-step KL objective that unifies both stochastic SDE and deterministic ODE refinement via mean-matching. We formally and empirically demonstrate that this analytic gradient provides lower variance and better generality compared to conventional PPO-style policy gradients. Extensive experiments show that DiffusionOPD consistently surpasses both multi-reward RL and cascade RL baselines in training efficiency and final performance, while achieving state-of-the-art results on all evaluated benchmarks.
format Preprint
id arxiv_https___arxiv_org_abs_2605_15055
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle DiffusionOPD: A Unified Perspective of On-Policy Distillation in Diffusion Models
Li, Quanhao
Yu, Junqiu
Jiang, Kaixun
Wei, Yujie
Xing, Zhen
Li, Pandeng
Chu, Ruihang
Zhang, Shiwei
Liu, Yu
Wu, Zuxuan
Machine Learning
Computer Vision and Pattern Recognition
Reinforcement learning has emerged as a powerful tool for improving diffusion-based text-to-image models, but existing methods are largely limited to single-task optimization. Extending RL to multiple tasks is challenging: joint optimization suffers from cross-task interference and imbalance, while cascade RL is cumbersome and prone to catastrophic forgetting. We propose DiffusionOPD, a new multi-task training paradigm for diffusion models based on Online Policy Distillation (OPD). DiffusionOPD first trains task-specific teachers independently, then distills their capabilities into a unified student along the student own rollout trajectories. This decouples single-task exploration from multi-task integration and avoids the optimization burden of solving all tasks jointly from scratch. Theoretically, we lift the OPD framework from discrete tokens to continuous-state Markov processes, deriving a closed-form per-step KL objective that unifies both stochastic SDE and deterministic ODE refinement via mean-matching. We formally and empirically demonstrate that this analytic gradient provides lower variance and better generality compared to conventional PPO-style policy gradients. Extensive experiments show that DiffusionOPD consistently surpasses both multi-reward RL and cascade RL baselines in training efficiency and final performance, while achieving state-of-the-art results on all evaluated benchmarks.
title DiffusionOPD: A Unified Perspective of On-Policy Distillation in Diffusion Models
topic Machine Learning
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2605.15055