IR-Flow: Bridging Discriminative and Generative Image Restoration via Rectified Flow

Fuente: arXiv
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Main Authors: Fan, Zihao, Lu, Xin, Xiao, Jie, Li, Dong, Huang, Jie, Fu, Xueyang
Format: Preprint
Published: 2026
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author Fan, Zihao
Lu, Xin
Xiao, Jie
Li, Dong
Huang, Jie
Fu, Xueyang
author_facet Fan, Zihao
Lu, Xin
Xiao, Jie
Li, Dong
Huang, Jie
Fu, Xueyang
contents In image restoration, single-step discriminative mappings often lack fine details via expectation learning, whereas generative paradigms suffer from inefficient multi-step sampling and noise-residual coupling. To address this dilemma, we propose IR-Flow, a novel image restoration method based on Rectified Flow that serves as a unified framework bridging the gap between discriminative and generative paradigms. Specifically, we first construct multilevel data distribution flows, which expand the ability of models to learn from and adapt to various levels of degradation. Subsequently, cumulative velocity fields are proposed to learn transport trajectories across varying degradation levels, guiding intermediate states toward the clean target, while a multi-step consistency constraint is presented to enforce trajectory coherence and boost few-step restoration performance. We show that directly establishing a linear transport flow between degraded and clean image domains not only enables fast inference but also improves adaptability to out-of-distribution degradations. Extensive evaluations on deraining, denoising and raindrop removal tasks demonstrate that IR-Flow achieves competitive quantitative results with only a few sampling steps, offering an efficient and flexible framework that maintains an excellent distortion-perception balance. Our code is available at https://github.com/fanzh03/IR-Flow.
format Preprint
id arxiv_https___arxiv_org_abs_2604_19680
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle IR-Flow: Bridging Discriminative and Generative Image Restoration via Rectified Flow
Fan, Zihao
Lu, Xin
Xiao, Jie
Li, Dong
Huang, Jie
Fu, Xueyang
Computer Vision and Pattern Recognition
In image restoration, single-step discriminative mappings often lack fine details via expectation learning, whereas generative paradigms suffer from inefficient multi-step sampling and noise-residual coupling. To address this dilemma, we propose IR-Flow, a novel image restoration method based on Rectified Flow that serves as a unified framework bridging the gap between discriminative and generative paradigms. Specifically, we first construct multilevel data distribution flows, which expand the ability of models to learn from and adapt to various levels of degradation. Subsequently, cumulative velocity fields are proposed to learn transport trajectories across varying degradation levels, guiding intermediate states toward the clean target, while a multi-step consistency constraint is presented to enforce trajectory coherence and boost few-step restoration performance. We show that directly establishing a linear transport flow between degraded and clean image domains not only enables fast inference but also improves adaptability to out-of-distribution degradations. Extensive evaluations on deraining, denoising and raindrop removal tasks demonstrate that IR-Flow achieves competitive quantitative results with only a few sampling steps, offering an efficient and flexible framework that maintains an excellent distortion-perception balance. Our code is available at https://github.com/fanzh03/IR-Flow.
title IR-Flow: Bridging Discriminative and Generative Image Restoration via Rectified Flow
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2604.19680