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This paper focuses on the development of a space-variant regularization model for solving an under-determined linear inverse problem. The case study is a medical image reconstruction from few-view tomographic noisy data. The primary…

Image and Video Processing · Electrical Eng. & Systems 2024-04-29 Elena Morotti , Davide Evangelista , Andrea Sebastiani , Elena Loli Piccolomini

We present a family of non-local variational regularization methods for solving tomographic problems, where the solutions are functions with range in a closed subset of the Euclidean space, for example if the solution only attains values in…

Optimization and Control · Mathematics 2019-11-18 Melanie Melching , Otmar Scherzer

Non-stationary blind super-resolution is an extension of the traditional super-resolution problem, which deals with the problem of recovering fine details from coarse measurements. The non-stationary blind super-resolution problem appears…

Information Theory · Computer Science 2019-10-09 Shuang Li , Michael B. Wakin , Gongguo Tang

We shall investigate randomized algorithms for solving large-scale linear inverse problems with general regularizations. We first present some techniques to transform inverse problems of general form into the ones of standard form, then…

Numerical Analysis · Mathematics 2014-12-30 Hua Xiang , Jun Zou

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

We investigate a level-set type method for solving ill-posed problems, with the assumption that the solutions are piecewise, but not necessarily constant functions with unknown level sets and unknown level values. In order to get stable…

Numerical Analysis · Mathematics 2012-10-30 Adriano De Cezaro

Reconstructing the structure of the soil using non-invasive techniques is a very relevant problem in many scientific fields, like geophysics and archaeology. This can be done, for instance, with the aid of Frequency Domain Electromagnetic…

Numerical Analysis · Mathematics 2022-01-05 Alessandro Buccini , Patricia Díaz de Alba

Connected with the rise of interest in inverse problems is the development and analysis of regularization methods, which are a necessity due to the ill-posedness of inverse problems. Tikhonov-type regularization methods are very popular in…

Numerical Analysis · Mathematics 2021-03-16 Abinash Nayak

Wavelet (Besov) priors are a promising way of reconstructing indirectly measured fields in a regularized manner. We demonstrate how wavelets can be used as a localized basis for reconstructing permeability fields with sharp interfaces from…

Numerical Analysis · Mathematics 2019-07-09 Philipp Wacker , Peter Knabner

In many linear regression problems, including ill-posed inverse problems in image restoration, the data exhibit some sparse structures that can be used to regularize the inversion. To this end, a classical path is to use $\ell_{12}$ block…

Signal Processing · Electrical Eng. & Systems 2021-10-25 Charles-Alban Deledalle , Nicolas Papadakis , Joseph Salmon , Samuel Vaiter

The analysis of surface wave dispersion curves is a way to infer the vertical distribution of shear-wave velocity. The range of applicability is extremely wide going, for example, from seismological studies to geotechnical characterizations…

Geophysics · Physics 2021-02-25 Giulio Vignoli , Julien Guillemoteau , Jeniffer Barreto , Matteo Rossi

In this work, we investigate the use of Besov priors in the context of Bayesian inverse problems. The solution to Bayesian inverse problems is the posterior distribution which naturally enables us to interpret the uncertainties. Besov…

Numerical Analysis · Mathematics 2025-06-23 Andreas Horst , Babak Maboudi Afkham , Yiqiu Dong , Jakob Lemvig

Wavelet frame systems are known to be effective in capturing singularities from noisy and degraded images. In this paper, we introduce a new edge driven wavelet frame model for image restoration by approximating images as piecewise smooth…

Numerical Analysis · Mathematics 2017-01-26 Jae Kyu Choi , Bin Dong , Xiaoqun Zhang

Estimating the values of unknown parameters from corrupted measured data faces a lot of challenges in ill-posed problems. In such problems, many fundamental estimation methods fail to provide a meaningful stabilized solution. In this work,…

Information Theory · Computer Science 2017-01-11 Mohamed Suliman , Tarig Ballal , Tareq Y. Al-Naffouri

We analyze the problem of global reconstruction of functions as accurately as possible, based on partial information in the form of a truncated power series at some point, and additional analyticity properties. This situation occurs…

Complex Variables · Mathematics 2022-05-30 Ovidiu Costin , Gerald V. Dunne

We consider the efficient minimization of a nonlinear, strictly convex functional with $\ell_1$-penalty term. Such minimization problems appear in a wide range of applications like Tikhonov regularization of (non)linear inverse problems…

Optimization and Control · Mathematics 2016-04-12 Esther Hans , Thorsten Raasch

These lecture notes for a graduate class present the regularization theory for linear and nonlinear ill-posed operator equations in Hilbert spaces. Covered are the general framework of regularization methods and their analysis via spectral…

Functional Analysis · Mathematics 2021-02-09 Christian Clason

We study the seismic inverse problem for the recovery of subsurface properties in acoustic media. In order to reduce the ill-posedness of the problem, the heterogeneous wave speed parameter to be recovered is represented using a limited…

Analysis of PDEs · Mathematics 2020-09-10 Florian Faucher , Otmar Scherzer , Hélène Barucq

We propose a convex variational principle to find sparse representation of low-lying eigenspace of symmetric matrices. In the context of electronic structure calculation, this corresponds to a sparse density matrix minimization algorithm…

Mathematical Physics · Physics 2014-03-11 Rongjie Lai , Jianfeng Lu , Stanley Osher

For electrical impedance tomography (EIT), most practical reconstruction methods are based on linearizing the underlying non-linear inverse problem. Recently, it has been shown that the linearized problem still contains the exact shape…

Numerical Analysis · Mathematics 2018-11-20 Moon Kyung Choi , Bastian Harrach , Jin Keun Seo
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