OmniRefiner: Reinforcement-Guided Local Diffusion Refinement

TL;DR

OmniRefiner is a two-stage, reinforcement learning-guided diffusion framework that significantly improves detail preservation and reference alignment in image refinement tasks, outperforming existing methods.

Contribution

It introduces a novel detail-aware refinement process combining diffusion editing and reinforcement learning for enhanced image editing fidelity.

Findings

Achieves superior reference alignment compared to existing models.

Enhances fine-grained detail preservation in image refinement.

Produces more visually coherent and faithful edits on benchmark datasets.

Abstract

Reference-guided image generation has progressed rapidly, yet current diffusion models still struggle to preserve fine-grained visual details when refining a generated image using a reference. This limitation arises because VAE-based latent compression inherently discards subtle texture information, causing identity- and attribute-specific cues to vanish. Moreover, post-editing approaches that amplify local details based on existing methods often produce results inconsistent with the original image in terms of lighting, texture, or shape. To address this, we introduce \ourMthd{}, a detail-aware refinement framework that performs two consecutive stages of reference-driven correction to enhance pixel-level consistency. We first adapt a single-image diffusion editor by fine-tuning it to jointly ingest the draft image and the reference image, enabling globally coherent refinement while maintaining structural fidelity. We then apply reinforcement learning to further strengthen localized editing capability, explicitly optimizing for detail accuracy and semantic consistency. Extensive experiments demonstrate that \ourMthd{} significantly improves reference alignment and fine-grained detail preservation, producing faithful and visually coherent edits that surpass both open-source and commercial models on challenging reference-guided restoration benchmarks.