Denoising, Fast and Slow: Difficulty-Aware Adaptive Sampling for Image Generation

Fuente: arXiv
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Autori principali: Schusterbauer, Johannes, Gui, Ming, Li, Yusong, Ma, Pingchuan, Krause, Felix, Ommer, Björn
Natura: Preprint
Pubblicazione: 2026
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author Schusterbauer, Johannes
Gui, Ming
Li, Yusong
Ma, Pingchuan
Krause, Felix
Ommer, Björn
author_facet Schusterbauer, Johannes
Gui, Ming
Li, Yusong
Ma, Pingchuan
Krause, Felix
Ommer, Björn
contents Diffusion- and flow-based models usually allocate compute uniformly across space, updating all patches with the same timestep and number of function evaluations. While convenient, this ignores the heterogeneity of natural images: some regions are easy to denoise, whereas others benefit from more refinement or additional context. Motivated by this, we explore patch-level noise scales for image synthesis. We find that naively varying timesteps across image tokens performs poorly, as it exposes the model to overly informative training states that do not occur at inference. We therefore introduce a timestep sampler that explicitly controls the maximum patch-level information available during training, and show that moving from global to patch-level timesteps already improves image generation over standard baselines. By further augmenting the model with a lightweight per-patch difficulty head, we enable adaptive samplers that allocate compute dynamically where it is most needed. Combined with noise levels varying over both space and diffusion time, this yields Patch Forcing (PF), a framework that advances easier regions earlier so they can provide context for harder ones. PF achieves superior results on class-conditional ImageNet, remains orthogonal to representation alignment and guidance methods, and scales to text-to-image synthesis. Our results suggest that patch-level denoising schedules provide a promising foundation for adaptive image generation.
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id arxiv_https___arxiv_org_abs_2604_19141
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Denoising, Fast and Slow: Difficulty-Aware Adaptive Sampling for Image Generation
Schusterbauer, Johannes
Gui, Ming
Li, Yusong
Ma, Pingchuan
Krause, Felix
Ommer, Björn
Computer Vision and Pattern Recognition
Diffusion- and flow-based models usually allocate compute uniformly across space, updating all patches with the same timestep and number of function evaluations. While convenient, this ignores the heterogeneity of natural images: some regions are easy to denoise, whereas others benefit from more refinement or additional context. Motivated by this, we explore patch-level noise scales for image synthesis. We find that naively varying timesteps across image tokens performs poorly, as it exposes the model to overly informative training states that do not occur at inference. We therefore introduce a timestep sampler that explicitly controls the maximum patch-level information available during training, and show that moving from global to patch-level timesteps already improves image generation over standard baselines. By further augmenting the model with a lightweight per-patch difficulty head, we enable adaptive samplers that allocate compute dynamically where it is most needed. Combined with noise levels varying over both space and diffusion time, this yields Patch Forcing (PF), a framework that advances easier regions earlier so they can provide context for harder ones. PF achieves superior results on class-conditional ImageNet, remains orthogonal to representation alignment and guidance methods, and scales to text-to-image synthesis. Our results suggest that patch-level denoising schedules provide a promising foundation for adaptive image generation.
title Denoising, Fast and Slow: Difficulty-Aware Adaptive Sampling for Image Generation
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2604.19141