DRM: Diffusion-based Reward Model With Step-wise Guidance

Fuente: arXiv
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Main Authors: Zhang, Jaxon, Yang, Binxin, Yin, Hubery, Li, Chen, Lyu, Jing
Format: Preprint
Published: 2026
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author Zhang, Jaxon
Yang, Binxin
Yin, Hubery
Li, Chen
Lyu, Jing
author_facet Zhang, Jaxon
Yang, Binxin
Yin, Hubery
Li, Chen
Lyu, Jing
contents Current mainstream methods of aligning diffusion models with human preferences typically employ VLM-based reward models. However, these reward models, pre-trained for semantic alignment, struggle to capture the essential perceptual qualities-such as aesthetics, composition, and visual harmony. In this work, we argue that a model capable of high-fidelity generation must possess a profound understanding of these visual attributes. Based on this insight, we introduce the Diffusion-based Reward Model (DRM), a novel paradigm that use the pre-trained diffusion model as a powerful evaluative backbone. A key advantage of the DRM is its unique ability to assess not only the final image but also the noisy intermediate latents at any stage of the generative process. We leverage this step-wise evaluative capacity in two ways. First, we propose Step-wise GRPO, a reinforcement learning algorithm that provides dense, per-step rewards to resolve the imprecise credit assignment problem in GRPO algorithm, leading to more stable and effective alignment. Second, we introduce Step-wise Sampling, a novel inference strategy that employs the DRM as a dynamic guide to evaluate multiple generation paths at each step, steering the process towards higher-quality outcomes. Extensive experiments confirm that our approach significantly enhances the final quality of generated images. Code: https://github.com/jjaxonx/DRM.
format Preprint
id arxiv_https___arxiv_org_abs_2605_25661
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle DRM: Diffusion-based Reward Model With Step-wise Guidance
Zhang, Jaxon
Yang, Binxin
Yin, Hubery
Li, Chen
Lyu, Jing
Computer Vision and Pattern Recognition
Current mainstream methods of aligning diffusion models with human preferences typically employ VLM-based reward models. However, these reward models, pre-trained for semantic alignment, struggle to capture the essential perceptual qualities-such as aesthetics, composition, and visual harmony. In this work, we argue that a model capable of high-fidelity generation must possess a profound understanding of these visual attributes. Based on this insight, we introduce the Diffusion-based Reward Model (DRM), a novel paradigm that use the pre-trained diffusion model as a powerful evaluative backbone. A key advantage of the DRM is its unique ability to assess not only the final image but also the noisy intermediate latents at any stage of the generative process. We leverage this step-wise evaluative capacity in two ways. First, we propose Step-wise GRPO, a reinforcement learning algorithm that provides dense, per-step rewards to resolve the imprecise credit assignment problem in GRPO algorithm, leading to more stable and effective alignment. Second, we introduce Step-wise Sampling, a novel inference strategy that employs the DRM as a dynamic guide to evaluate multiple generation paths at each step, steering the process towards higher-quality outcomes. Extensive experiments confirm that our approach significantly enhances the final quality of generated images. Code: https://github.com/jjaxonx/DRM.
title DRM: Diffusion-based Reward Model With Step-wise Guidance
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2605.25661