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Diffusion posterior sampling solves inverse problems by combining a pretrained diffusion prior with measurement-consistency guidance, but it often fails to recover fine details because measurement terms are applied in a manner that is…

Computer Vision and Pattern Recognition · Computer Science 2026-02-03 Feng Tian , Yixuan Li , Weili Zeng , Weitian Zhang , Yichao Yan , Xiaokang Yang

In this paper we introduce a model describing diffusion of species by a suitable regularization of a "forward-backward" parabolic equation. In particular, we prove existence and uniqueness of solutions, as well as continuous dependence on…

Analysis of PDEs · Mathematics 2015-08-14 Elena Bonetti , Pierluigi Colli , Giuseppe Tomassetti

X-ray ptychography is one of the versatile techniques for nanometer resolution imaging. The magnitude of the diffraction patterns is recorded on a detector and the phase of the diffraction patterns is estimated using phase retrieval…

Image and Video Processing · Electrical Eng. & Systems 2021-05-21 Prasan Shedligeri , Florian Schiffers , Semih Barutcu , Pablo Ruiz , Aggelos K Katsaggelos , Oliver Cossairt

Diffusion models are widely used for generative tasks across domains. Given a pre-trained diffusion model, it is often desirable to fine-tune it further either to correct for errors in learning or to align with downstream applications.…

Here we consider the problem of denoising features associated to complex data, modeled as signals on a graph, via a smoothness prior. This is motivated in part by settings such as single-cell RNA where the data is very high-dimensional, but…

Machine Learning · Computer Science 2023-12-12 Sam Leone , Xingzhi Sun , Michael Perlmutter , Smita Krishnaswamy

Diffusion models have been shown to implicitly generate visual content autoregressively in the frequency domain, where low-frequency components are generated earlier in the denoising process while high-frequency details emerge only in later…

Computer Vision and Pattern Recognition · Computer Science 2026-05-21 Howard Xiao , Brian Chao , Lior Yariv , Gordon Wetzstein

Generative diffusion models can provide powerful prior probability models for inverse problems in imaging, but existing implementations suffer from two key limitations: $(i)$ the prior density is represented implicitly, and $(ii)$ they rely…

Machine Learning · Computer Science 2026-05-19 Nicolas Zilberstein , Santiago Segarra , Eero Simoncelli , Florentin Guth

Radio-Frequency (RF) imaging concerns the digital recreation of the surfaces of scene objects based on the scattered field at distributed receivers. To solve this difficult inverse scattering problems, data-driven methods are often employed…

Machine Learning · Computer Science 2025-03-19 Kyriakos Stylianopoulos , Panagiotis Gavriilidis , Gabriele Gradoni , George C. Alexandropoulos

Denoising diffusion models are a powerful type of generative models used to capture complex distributions of real-world signals. However, their applicability is limited to scenarios where training samples are readily available, which is not…

Computer Vision and Pattern Recognition · Computer Science 2023-11-20 Ayush Tewari , Tianwei Yin , George Cazenavette , Semon Rezchikov , Joshua B. Tenenbaum , Frédo Durand , William T. Freeman , Vincent Sitzmann

The total variation (TV) regularization has phenomenally boosted various variational models for image processing tasks. We propose to combine the backward diffusion process in the earlier literature of image enhancement with the TV…

Image and Video Processing · Electrical Eng. & Systems 2023-06-14 Congpei An , Hao-Ning Wu , Xiaoming Yuan

We propose self-diffusion, a novel framework for solving inverse problems without relying on pretrained generative models. Traditional diffusion-based approaches require training a model on a clean dataset to learn to reverse the forward…

Machine Learning · Computer Science 2025-12-09 Guanxiong Luo , Shoujin Huang , Yanlong Yang

In recent years, Graph Neural Networks (GNNs) have been utilized for various applications ranging from drug discovery to network design and social networks. In many applications, it is impossible to observe some properties of the graph…

Machine Learning · Computer Science 2025-03-12 Moshe Eliasof , Md Shahriar Rahim Siddiqui , Carola-Bibiane Schönlieb , Eldad Haber

Recently, diffusion models have shown remarkable results in image synthesis by gradually removing noise and amplifying signals. Although the simple generative process surprisingly works well, is this the best way to generate image data? For…

Computer Vision and Pattern Recognition · Computer Science 2022-11-22 Sangyun Lee , Hyungjin Chung , Jaehyeon Kim , Jong Chul Ye

Signal reconstruction is a challenging aspect of computational imaging as it often involves solving ill-posed inverse problems. Recently, deep feed-forward neural networks have led to state-of-the-art results in solving various inverse…

Computer Vision and Pattern Recognition · Computer Science 2018-04-25 Akshat Dave , Anil Kumar Vadathya , Ramana Subramanyam , Rahul Baburajan , Kaushik Mitra

This paper formulates a multitask optimization problem where agents in the network have individual objectives to meet, or individual parameter vectors to estimate, subject to a smoothness condition over the graph. The smoothness condition…

Multiagent Systems · Computer Science 2019-11-18 Roula Nassif , Stefan Vlaski , Cedric Richard , Ali H. Sayed

Fine-tuning Stable Diffusion enables subject-driven image synthesis by adapting the model to generate images containing specific subjects. However, existing fine-tuning methods suffer from two key issues: underfitting, where the model fails…

Graphics · Computer Science 2025-06-10 Yao Ni , Song Wen , Piotr Koniusz , Anoop Cherian

Natural images tend to mostly consist of smooth regions with individual pixels having highly correlated spectra. This information can be exploited to recover hyperspectral images of natural scenes from their incomplete and noisy…

Computer Vision and Pattern Recognition · Computer Science 2016-11-03 Reza Arablouei , Frank de Hoog

Most real-world networks are noisy and incomplete samples from an unknown target distribution. Refining them by correcting corruptions or inferring unobserved regions typically improves downstream performance. Inspired by the impressive…

In this paper, we propose an interpretable denoising method for graph signals using regularization by denoising (RED). RED is a technique developed for image restoration that uses an efficient (and sometimes black-box) denoiser in the…

Signal Processing · Electrical Eng. & Systems 2026-05-27 Hayate Kojima , Hiroshi Higashi , Yuichi Tanaka

We investigate the dynamical sampling space-time trade-off problem within a graph setting. Specifically, we derive necessary and sufficient conditions for space-time sampling that enable the reconstruction of an initial band-limited signal…

Information Theory · Computer Science 2024-11-20 Akram Aldroubi , Victor Bailey , Ilya Krishtal , Brendan Miller , Armenak Petrosyan