Tackling the Singularities at the Endpoints of Time Intervals in Diffusion Models

Fuente: arXiv
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Autores principales: Zhang, Pengze, Yin, Hubery, Li, Chen, Xie, Xiaohua
Formato: Preprint
Publicado: 2024
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author Zhang, Pengze
Yin, Hubery
Li, Chen
Xie, Xiaohua
author_facet Zhang, Pengze
Yin, Hubery
Li, Chen
Xie, Xiaohua
contents Most diffusion models assume that the reverse process adheres to a Gaussian distribution. However, this approximation has not been rigorously validated, especially at singularities, where t=0 and t=1. Improperly dealing with such singularities leads to an average brightness issue in applications, and limits the generation of images with extreme brightness or darkness. We primarily focus on tackling singularities from both theoretical and practical perspectives. Initially, we establish the error bounds for the reverse process approximation, and showcase its Gaussian characteristics at singularity time steps. Based on this theoretical insight, we confirm the singularity at t=1 is conditionally removable while it at t=0 is an inherent property. Upon these significant conclusions, we propose a novel plug-and-play method SingDiffusion to address the initial singular time step sampling, which not only effectively resolves the average brightness issue for a wide range of diffusion models without extra training efforts, but also enhances their generation capability in achieving notable lower FID scores.
format Preprint
id arxiv_https___arxiv_org_abs_2403_08381
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Tackling the Singularities at the Endpoints of Time Intervals in Diffusion Models
Zhang, Pengze
Yin, Hubery
Li, Chen
Xie, Xiaohua
Computer Vision and Pattern Recognition
Most diffusion models assume that the reverse process adheres to a Gaussian distribution. However, this approximation has not been rigorously validated, especially at singularities, where t=0 and t=1. Improperly dealing with such singularities leads to an average brightness issue in applications, and limits the generation of images with extreme brightness or darkness. We primarily focus on tackling singularities from both theoretical and practical perspectives. Initially, we establish the error bounds for the reverse process approximation, and showcase its Gaussian characteristics at singularity time steps. Based on this theoretical insight, we confirm the singularity at t=1 is conditionally removable while it at t=0 is an inherent property. Upon these significant conclusions, we propose a novel plug-and-play method SingDiffusion to address the initial singular time step sampling, which not only effectively resolves the average brightness issue for a wide range of diffusion models without extra training efforts, but also enhances their generation capability in achieving notable lower FID scores.
title Tackling the Singularities at the Endpoints of Time Intervals in Diffusion Models
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2403.08381