Optimizing Diffusion Priors in Image Reconstruction from a Single Observation

Fuente: arXiv
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Main Authors: Wang, Frederic, Bouman, Katherine L.
Format: Preprint
Published: 2026
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author Wang, Frederic
Bouman, Katherine L.
author_facet Wang, Frederic
Bouman, Katherine L.
contents While diffusion priors generate high-quality posterior samples across many inverse problems, they are often trained on limited training sets or purely simulated data, thus inheriting the errors and biases of these underlying sources. Current approaches to finetuning diffusion models rely on a large number of observations with varying forward operators, which can be difficult to collect for many applications, and thus lead to overfitting when the measurement set is small. We propose a method for tuning a prior from only a single observation by combining existing diffusion priors into a single product-of-experts prior and identifying the exponents that maximize the Bayesian evidence. We validate our method on real-world inverse problems, including black hole imaging, where the true prior is unknown a priori, and image deblurring with text-conditioned priors. We find that the evidence is often maximized by priors that extend beyond those trained on a single dataset. By generalizing the prior through exponent weighting, our approach enables posterior sampling from both tempered and combined diffusion models, yielding more flexible priors that improve the trustworthiness of the resulting posterior image distribution.
format Preprint
id arxiv_https___arxiv_org_abs_2604_21066
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Optimizing Diffusion Priors in Image Reconstruction from a Single Observation
Wang, Frederic
Bouman, Katherine L.
Computer Vision and Pattern Recognition
Machine Learning
Methodology
While diffusion priors generate high-quality posterior samples across many inverse problems, they are often trained on limited training sets or purely simulated data, thus inheriting the errors and biases of these underlying sources. Current approaches to finetuning diffusion models rely on a large number of observations with varying forward operators, which can be difficult to collect for many applications, and thus lead to overfitting when the measurement set is small. We propose a method for tuning a prior from only a single observation by combining existing diffusion priors into a single product-of-experts prior and identifying the exponents that maximize the Bayesian evidence. We validate our method on real-world inverse problems, including black hole imaging, where the true prior is unknown a priori, and image deblurring with text-conditioned priors. We find that the evidence is often maximized by priors that extend beyond those trained on a single dataset. By generalizing the prior through exponent weighting, our approach enables posterior sampling from both tempered and combined diffusion models, yielding more flexible priors that improve the trustworthiness of the resulting posterior image distribution.
title Optimizing Diffusion Priors in Image Reconstruction from a Single Observation
topic Computer Vision and Pattern Recognition
Machine Learning
Methodology
url https://arxiv.org/abs/2604.21066