Diff-Unfolding: A Model-Based Score Learning Framework for Inverse Problems

Fuente: arXiv
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Autori principali: Wang, Yuanhao, Shoushtari, Shirin, Kamilov, Ulugbek S.
Natura: Preprint
Pubblicazione: 2025
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author Wang, Yuanhao
Shoushtari, Shirin
Kamilov, Ulugbek S.
author_facet Wang, Yuanhao
Shoushtari, Shirin
Kamilov, Ulugbek S.
contents Diffusion models are extensively used for modeling image priors for inverse problems. We introduce \emph{Diff-Unfolding}, a principled framework for learning posterior score functions of \emph{conditional diffusion models} by explicitly incorporating the physical measurement operator into a modular network architecture. Diff-Unfolding formulates posterior score learning as the training of an unrolled optimization scheme, where the measurement model is decoupled from the learned image prior. This design allows our method to generalize across inverse problems at inference time by simply replacing the forward operator without retraining. We theoretically justify our unrolling approach by showing that the posterior score can be derived from a composite model-based optimization formulation. Extensive experiments on image restoration and accelerated MRI show that Diff-Unfolding achieves state-of-the-art performance, improving PSNR by up to 2 dB and reducing LPIPS by $22.7\%$, while being both compact (47M parameters) and efficient (0.72 seconds per $256 \times 256$ image). An optimized C++/LibTorch implementation further reduces inference time to 0.63 seconds, underscoring the practicality of our approach.
format Preprint
id arxiv_https___arxiv_org_abs_2505_11393
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Diff-Unfolding: A Model-Based Score Learning Framework for Inverse Problems
Wang, Yuanhao
Shoushtari, Shirin
Kamilov, Ulugbek S.
Image and Video Processing
Diffusion models are extensively used for modeling image priors for inverse problems. We introduce \emph{Diff-Unfolding}, a principled framework for learning posterior score functions of \emph{conditional diffusion models} by explicitly incorporating the physical measurement operator into a modular network architecture. Diff-Unfolding formulates posterior score learning as the training of an unrolled optimization scheme, where the measurement model is decoupled from the learned image prior. This design allows our method to generalize across inverse problems at inference time by simply replacing the forward operator without retraining. We theoretically justify our unrolling approach by showing that the posterior score can be derived from a composite model-based optimization formulation. Extensive experiments on image restoration and accelerated MRI show that Diff-Unfolding achieves state-of-the-art performance, improving PSNR by up to 2 dB and reducing LPIPS by $22.7\%$, while being both compact (47M parameters) and efficient (0.72 seconds per $256 \times 256$ image). An optimized C++/LibTorch implementation further reduces inference time to 0.63 seconds, underscoring the practicality of our approach.
title Diff-Unfolding: A Model-Based Score Learning Framework for Inverse Problems
topic Image and Video Processing
url https://arxiv.org/abs/2505.11393