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arXiv 2605.22011cs.CV

重新思考扩散模型的token减少:通过输出相似性意识

Rethinking Token Reduction for Diffusion Models via Output-Similarity-Awareness

KAIST(韩国科学技术院)

Hangyeol Lee, Hyojeong Lee, Joo-Young Kim

AI总结:

本文提出DiTo,一种基于输出中心的token减少方法,通过利用相邻时间步的输出相似性来建立token对应关系,从而减少计算复杂度并提高生成质量。

摘要:

扩散变换器(DiTs)在图像生成质量上表现出色,但其计算复杂度与token数量呈二次关系。尽管已提出多种token减少(TR)方法以缓解这一成本,但它们忽略了生成模型的主要目标:最小化恢复误差,这需要反映输出token的相似性。它们仅依赖于输入token相似性,这是来自仅减少的ViT范式继承的,导致与该目标的根本不一致。为弥合这一差距,我们提出DiTo,一种新的TR范式,其重点转向以输出为中心的token减少。基于观察到输出token相似性在相邻时间步中保持一致,DiTo利用先前步骤的相似性作为有效代理,在匹配时间步中建立token对应关系,然后在多个后续减少时间步中重用。为了优化这种交错调度,我们提出Pair Match Ratio(PMR)引导的区间调度,以确定最佳匹配频率。此外,为了减轻由重复重用导致的局部近似误差和由此产生的阻塞伪影,我们提出频率感知的token匹配,通过引入选择频率惩罚。广泛的实验表明,DiTo在可比的加速下,比现有TR方法在PSNR上高出1.6-3.9 dB,实现了更优的帕累托前沿。

英文摘要:

Diffusion Transformers (DiTs) achieve superior image generation quality but suffer from quadratic computational complexity relative to token count. While various token reduction (TR) methods have been proposed to mitigate this cost, they overlook the primary objective of generative models: minimizing recovery error, which requires reflecting output token similarity. They rely solely on input token similarity inherited from reduction-only ViT paradigms, leading to a fundamental misalignment with this objective. To bridge this gap, we propose DiTo, a novel TR paradigm that shifts the focus toward output-centric token reduction. Based on the observation that output token similarity is consistently preserved across adjacent timesteps, DiTo utilizes prior-step similarities as an effective proxy to establish token correspondences at a Matching timestep, which are then reused across multiple subsequent Reduction timesteps. To optimize this interleaved scheduling, we propose Pair Match Ratio (PMR)-guided Interval Scheduling to determine the optimal matching frequency. Furthermore, to mitigate localized approximation errors and resulting blocking artifacts caused by repeated reuse, we propose Frequency-aware Token Matching by incorporating a selection-frequency penalty. Extensive experiments demonstrate that DiTo consistently outperforms existing TR methods with 1.6-3.9 dB higher PSNR at comparable speedups, achieving a superior Pareto frontier.

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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