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Related papers: Plug-and-Play Regularization using Linear Solvers

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Regularization and interior point approaches offer valuable perspectives to address constrained nonlinear optimization problems in view of control applications. This paper discusses the interactions between these techniques and proposes an…

Optimization and Control · Mathematics 2022-10-31 Alberto De Marchi

Inverse problems arise in a variety of imaging applications including computed tomography, non-destructive testing, and remote sensing. The characteristic features of inverse problems are the non-uniqueness and instability of their…

Numerical Analysis · Mathematics 2020-06-09 Markus Haltmeier , Linh V. Nguyen

In this work, we consider the linear inverse problem $y=Ax+\epsilon$, where $A\colon X\to Y$ is a known linear operator between the separable Hilbert spaces $X$ and $Y$, $x$ is a random variable in $X$ and $\epsilon$ is a zero-mean random…

Machine Learning · Statistics 2021-11-23 Giovanni S. Alberti , Ernesto De Vito , Matti Lassas , Luca Ratti , Matteo Santacesaria

We aim at the solution of inverse problems in imaging, by combining a penalized sparse representation of image patches with an unconstrained smooth one. This allows for a straightforward interpretation of the reconstruction. We formulate…

Image and Video Processing · Electrical Eng. & Systems 2025-03-18 Stanislas Ducotterd , Sebastian Neumayer , Michael Unser

We use convex relaxation techniques to provide a sequence of solutions to the matrix completion problem. Using the nuclear norm as a regularizer, we provide simple and very efficient algorithms for minimizing the reconstruction error…

Machine Learning · Statistics 2009-06-12 Rahul Mazumder , Trevor Hastie , Rob Tibshirani

We propose a sparse reconstruction framework for solving inverse problems. Opposed to existing sparse regularization techniques that are based on frame representations, we train an encoder-decoder network by including an $\ell^1$-penalty.…

Numerical Analysis · Mathematics 2019-08-07 Daniel Obmann , Johannes Schwab , Markus Haltmeier

We propose a general deep plug-and-play (PnP) algorithm with a theoretical convergence guarantee. PnP strategies have demonstrated outstanding performance in various image restoration tasks by exploiting the powerful priors underlying…

Image and Video Processing · Electrical Eng. & Systems 2025-12-19 Yodai Suzuki , Ryosuke Isono , Shunsuke Ono

In this paper, a new regularization term is proposed to solve mathematical image problems. By using difference operators in the four directions; horizontal, vertical and two diagonal directions, an estimation of derivative amplitude is…

Numerical Analysis · Mathematics 2022-09-14 Alireza Hosseini

In this work we consider a generalized bilevel optimization framework for solving inverse problems. We introduce fractional Laplacian as a regularizer to improve the reconstruction quality, and compare it with the total variation…

Image and Video Processing · Electrical Eng. & Systems 2020-06-24 Harbir Antil , Zichao Di , Ratna Khatri

Regularization by denoising (RED) is a broadly applicable framework for solving inverse problems by using priors specified as denoisers. While RED has been shown to provide state-of-the-art performance in a number of applications, existing…

Image and Video Processing · Electrical Eng. & Systems 2020-11-30 Mingyang Xie , Yu Sun , Jiaming Liu , Brendt Wohlberg , Ulugbek S. Kamilov

We consider the problem of estimating the slope function in a functional regression with a scalar response and a functional covariate. This central problem of functional data analysis is well known to be ill-posed, thus requiring a…

Methodology · Statistics 2016-10-05 Anirvan Chakraborty , Victor M. Panaretos

It's well-known that inverse problems are ill-posed and to solve them meaningfully, one has to employ regularization methods. Traditionally, popular regularization methods are the penalized Variational approaches. In recent years, the…

Computer Vision and Pattern Recognition · Computer Science 2021-09-06 Abinash Nayak

The use of Plug-and-Play (PnP) methods has become a central approach for solving inverse problems, with denoisers serving as regularising priors that guide optimisation towards a clean solution. In this work, we introduce KAN-PnP, an…

Computer Vision and Pattern Recognition · Computer Science 2025-05-05 Yanqi Cheng , Carola-Bibiane Schönlieb , Angelica I Aviles-Rivero

In this study, the problem of computing a sparse representation of multi-dimensional visual data is considered. In general, such data e.g., hyperspectral images, color images or video data consists of signals that exhibit strong local…

Computer Vision and Pattern Recognition · Computer Science 2023-03-16 Alexandros Gkillas , Dimitris Ampeliotis , Kostas Berberidis

We present a general variational framework for the training of freeform nonlinearities in layered computational architectures subject to some slope constraints. The regularization that we add to the traditional training loss penalizes the…

Machine Learning · Statistics 2025-03-31 Michael Unser , Alexis Goujon , Stanislas Ducotterd

The image deblurring problem consists of reconstructing images from blur and noise contaminated available data. In this AMS Notices article, we provide an overview of some well known numerical linear algebra techniques that are use for…

Numerical Analysis · Mathematics 2022-01-25 David Austin , Malena I. Español , Mirjeta Pasha

Image deconvolution is still to be a challenging ill-posed problem for recovering a clear image from a given blurry image, when the point spread function is known. Although competitive deconvolution methods are numerically impressive and…

Computer Vision and Pattern Recognition · Computer Science 2016-09-07 Hang Yang , Zhongbo Zhang , Yujing Guan

Image denoising is a classical problem in low level computer vision. Model-based optimization methods and deep learning approaches have been the two main strategies for solving the problem. Model-based optimization methods are flexible for…

Computer Vision and Pattern Recognition · Computer Science 2018-12-31 Chang Liu , Zhaowei Shang , Anyong Qin

We propose to learn non-convex regularizers with a prescribed upper bound on their weak-convexity modulus. Such regularizers give rise to variational denoisers that minimize a convex energy. They rely on few parameters (less than 15,000)…

Image and Video Processing · Electrical Eng. & Systems 2023-12-21 Alexis Goujon , Sebastian Neumayer , Michael Unser

This paper introduces a novel approach to learning sparsity-promoting regularizers for solving linear inverse problems. We develop a bilevel optimization framework to select an optimal synthesis operator, denoted as $B$, which regularizes…

Machine Learning · Statistics 2026-03-03 Giovanni S. Alberti , Ernesto De Vito , Tapio Helin , Matti Lassas , Luca Ratti , Matteo Santacesaria
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