arXiv:2507.07510cs.CVcs.LG2025-07被引 7

提出新方法让扩散模型更懂人类偏好,效果全面超越现有技术。

Divergence Minimization Preference Optimization for Diffusion Model Alignment

  • 通过最小化反向KL散度实现更优的偏好对齐
  • 在所有基线模型和测试集上均取得最佳PickScore
  • 理论严谨且实测表现稳定,适合生成质量要求高的场景

扩散模型在文本生成图像方面已取得显著进展。受语言模型发展的启发,研究者们尝试通过与人类偏好对齐来进一步提升模型性能。然而,我们从散度最小化的视角发现,现有偏好优化方法通常陷入次优的均值追逐优化。本文提出一种新的、原理严谨的方法——发散最小化偏好优化(DMPO),通过最小化反向KL散度,渐近地保持与原始强化学习一致的优化方向。我们提供了严格的理论分析,并通过全面实验验证其在人工评估和自动指标上的有效性。结果表明,经DMPO微调的扩散模型在不同基模型和测试集上均持续优于或匹配现有方法,且在所有情况下均取得最佳PickScore,充分证明了该方法在对齐生成行为与期望输出方面的优势。总体而言,DMPO为扩散模型的偏好对齐提供了一条稳健而优雅的路径,实现了理论严谨性与实际性能的统一。

原文摘要 · Abstract (English)

Diffusion models have achieved remarkable success in generating realistic and versatile images from text prompts. Inspired by the recent advancements of language models, there is an increasing interest in further improving the models by aligning with human preferences. However, we investigate alignment from a divergence minimization perspective and reveal that existing preference optimization methods are typically trapped in suboptimal mean-seeking optimization. In this paper, we introduce Divergence Minimization Preference Optimization (DMPO), a novel and principled method for aligning diffusion models by minimizing reverse KL divergence, which asymptotically enjoys the same optimization direction as original RL. We provide rigorous analysis to justify the effectiveness of DMPO and conduct comprehensive experiments to validate its empirical strength across both human evaluations and automatic metrics. Our extensive results show that diffusion models fine-tuned with DMPO can consistently outperform or match existing techniques, specifically consistently outperforming all baseline models across different base models and test sets, achieving the best PickScore in every case, demonstrating the method's superiority in aligning generative behavior with desired outputs. Overall, DMPO unlocks a robust and elegant pathway for preference alignment, bridging principled theory with practical performance in diffusion models.

扩散模型偏好对齐生成质量优化方法

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