CORAL: Disentangling Latent Representations in Long-Tailed Diffusion

Fuente: arXiv
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Main Authors: Rodriguez, Esther, Welfert, Monica, McDowell, Samuel, Stromberg, Nathan, Camarena, Julian Antolin, Sankar, Lalitha
Format: Preprint
Published: 2025
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author Rodriguez, Esther
Welfert, Monica
McDowell, Samuel
Stromberg, Nathan
Camarena, Julian Antolin
Sankar, Lalitha
author_facet Rodriguez, Esther
Welfert, Monica
McDowell, Samuel
Stromberg, Nathan
Camarena, Julian Antolin
Sankar, Lalitha
contents Diffusion models have achieved impressive performance in generating high-quality and diverse synthetic data. However, their success typically assumes a class-balanced training distribution. In real-world settings, multi-class data often follow a long-tailed distribution, where standard diffusion models struggle -- producing low-diversity and lower-quality samples for tail classes. While this degradation is well-documented, its underlying cause remains poorly understood. In this work, we investigate the behavior of diffusion models trained on long-tailed datasets and identify a key issue: the latent representations (from the bottleneck layer of the U-Net) for tail class subspaces exhibit significant overlap with those of head classes, leading to feature borrowing and poor generation quality. Importantly, we show that this is not merely due to limited data per class, but that the relative class imbalance significantly contributes to this phenomenon. To address this, we propose COntrastive Regularization for Aligning Latents (CORAL), a contrastive latent alignment framework that leverages supervised contrastive losses to encourage well-separated latent class representations. Experiments demonstrate that CORAL significantly improves both the diversity and visual quality of samples generated for tail classes relative to state-of-the-art methods.
format Preprint
id arxiv_https___arxiv_org_abs_2506_15933
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle CORAL: Disentangling Latent Representations in Long-Tailed Diffusion
Rodriguez, Esther
Welfert, Monica
McDowell, Samuel
Stromberg, Nathan
Camarena, Julian Antolin
Sankar, Lalitha
Machine Learning
Diffusion models have achieved impressive performance in generating high-quality and diverse synthetic data. However, their success typically assumes a class-balanced training distribution. In real-world settings, multi-class data often follow a long-tailed distribution, where standard diffusion models struggle -- producing low-diversity and lower-quality samples for tail classes. While this degradation is well-documented, its underlying cause remains poorly understood. In this work, we investigate the behavior of diffusion models trained on long-tailed datasets and identify a key issue: the latent representations (from the bottleneck layer of the U-Net) for tail class subspaces exhibit significant overlap with those of head classes, leading to feature borrowing and poor generation quality. Importantly, we show that this is not merely due to limited data per class, but that the relative class imbalance significantly contributes to this phenomenon. To address this, we propose COntrastive Regularization for Aligning Latents (CORAL), a contrastive latent alignment framework that leverages supervised contrastive losses to encourage well-separated latent class representations. Experiments demonstrate that CORAL significantly improves both the diversity and visual quality of samples generated for tail classes relative to state-of-the-art methods.
title CORAL: Disentangling Latent Representations in Long-Tailed Diffusion
topic Machine Learning
url https://arxiv.org/abs/2506.15933