Taming Sampling Perturbations with Variance Expansion Loss for Latent Diffusion Models

Fuente: arXiv
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Main Authors: Li, Qifan, Zhou, Xingyu, Zhang, Jinhua, You, Weiyi, Gu, Shuhang
Format: Preprint
Published: 2026
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author Li, Qifan
Zhou, Xingyu
Zhang, Jinhua
You, Weiyi
Gu, Shuhang
author_facet Li, Qifan
Zhou, Xingyu
Zhang, Jinhua
You, Weiyi
Gu, Shuhang
contents Latent diffusion models have emerged as the dominant framework for high-fidelity and efficient image generation, owing to their ability to learn diffusion processes in compact latent spaces. However, while previous research has focused primarily on reconstruction accuracy and semantic alignment of the latent space, we observe that another critical factor, robustness to sampling perturbations, also plays a crucial role in determining generation quality. Through empirical and theoretical analyses, we show that the commonly used $β$-VAE-based tokenizers in latent diffusion models, tend to produce overly compact latent manifolds that are highly sensitive to stochastic perturbations during diffusion sampling, leading to visual degradation. To address this issue, we propose a simple yet effective solution that constructs a latent space robust to sampling perturbations while maintaining strong reconstruction fidelity. This is achieved by introducing a Variance Expansion loss that counteracts variance collapse and leverages the adversarial interplay between reconstruction and variance expansion to achieve an adaptive balance that preserves reconstruction accuracy while improving robustness to stochastic sampling. Extensive experiments demonstrate that our approach consistently enhances generation quality across different latent diffusion architectures, confirming that robustness in latent space is a key missing ingredient for stable and faithful diffusion sampling.
format Preprint
id arxiv_https___arxiv_org_abs_2603_21085
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Taming Sampling Perturbations with Variance Expansion Loss for Latent Diffusion Models
Li, Qifan
Zhou, Xingyu
Zhang, Jinhua
You, Weiyi
Gu, Shuhang
Computer Vision and Pattern Recognition
Latent diffusion models have emerged as the dominant framework for high-fidelity and efficient image generation, owing to their ability to learn diffusion processes in compact latent spaces. However, while previous research has focused primarily on reconstruction accuracy and semantic alignment of the latent space, we observe that another critical factor, robustness to sampling perturbations, also plays a crucial role in determining generation quality. Through empirical and theoretical analyses, we show that the commonly used $β$-VAE-based tokenizers in latent diffusion models, tend to produce overly compact latent manifolds that are highly sensitive to stochastic perturbations during diffusion sampling, leading to visual degradation. To address this issue, we propose a simple yet effective solution that constructs a latent space robust to sampling perturbations while maintaining strong reconstruction fidelity. This is achieved by introducing a Variance Expansion loss that counteracts variance collapse and leverages the adversarial interplay between reconstruction and variance expansion to achieve an adaptive balance that preserves reconstruction accuracy while improving robustness to stochastic sampling. Extensive experiments demonstrate that our approach consistently enhances generation quality across different latent diffusion architectures, confirming that robustness in latent space is a key missing ingredient for stable and faithful diffusion sampling.
title Taming Sampling Perturbations with Variance Expansion Loss for Latent Diffusion Models
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2603.21085