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arXiv 2402.08265cs.CV
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从密集奖励视角看文本生成图像扩散模型的偏好对齐

A Dense Reward View on Aligning Text-to-Image Diffusion with Preference

The University of Texas at Austin(德克萨斯大学奥斯汀分校)

Shentao Yang, Tianqi Chen, Mingyuan Zhou

AI总结:

针对现有文本生成图像扩散模型偏好对齐方法忽略生成序列性的问题,本文从密集奖励视角出发,将时间折扣引入DPO式无显式奖励目标,提出适配T2I生成层级的对齐方法,实验效果与强基准相当。

摘要:

文本生成图像扩散模型(T2I)的偏好对齐正受到越来越多的研究关注。现有研究虽已利用偏好数据直接优化T2I,但这些方法均基于“整个扩散逆链存在潜在奖励”的赌博机假设展开,忽略了生成过程的序列特性,这可能会损害偏好对齐的效果与效率。本文从更精细的密集奖励视角出发,推导出一种易处理的对齐目标,该目标重点关注T2I逆链的初始步骤。具体而言,我们将时间折扣引入DPO(直接偏好优化)式的无显式奖励目标中,打破其中的时间对称性,以适配T2I的生成层级结构。在单提示与多提示生成的实验中,我们的方法在定量与定性层面均与性能强劲的相关基准模型相当。我们还开展了进一步研究以阐释本方法的核心思路。

英文摘要:

Aligning text-to-image diffusion model (T2I) with preference has been gaining increasing research attention. While prior works exist on directly optimizing T2I by preference data, these methods are developed under the bandit assumption of a latent reward on the entire diffusion reverse chain, while ignoring the sequential nature of the generation process. This may harm the efficacy and efficiency of preference alignment. In this paper, we take on a finer dense reward perspective and derive a tractable alignment objective that emphasizes the initial steps of the T2I reverse chain. In particular, we introduce temporal discounting into DPO-style explicit-reward-free objectives, to break the temporal symmetry therein and suit the T2I generation hierarchy. In experiments on single and multiple prompt generation, our method is competitive with strong relevant baselines, both quantitatively and qualitatively. Further investigations are conducted to illustrate the insight of our approach.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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