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We propose an extended full-waveform inversion formulation that includes general convex constraints on the model. Though the full problem is highly nonconvex, the overarching optimization scheme arrives at geologically plausible results by…

Optimization and Control · Mathematics 2016-08-23 Ernie Esser , Lluis Guasch , Tristan van Leeuwen , Aleksandr Y. Aravkin , Felix J. Herrmann

Electrical impedance tomography is an imaging modality for extracting information on the conductivity distribution inside a physical body from boundary measurements of current and voltage. In many practical applications, it is a priori…

Numerical Analysis · Mathematics 2014-06-06 Lauri Harhanen , Nuutti Hyvönen , Helle Majander , Stratos Staboulis

We introduce a method for fast estimation of data-adapted, spatio-temporally dependent regularization parameter-maps for variational image reconstruction, focusing on total variation (TV)-minimization. Our approach is inspired by recent…

Over the last decade or so, reconstruction methods using $\ell_1$ regularization, often categorized as compressed sensing (CS) algorithms, have significantly improved the capabilities of high fidelity imaging in electron tomography. The…

Numerical Analysis · Mathematics 2017-03-07 Toby Sanders , Anne Gelb , Rodrigo Platte , Ilke Arslan , Kai Landskron

Reconstructing images from ill-posed inverse problems often utilizes total variation regularization in order to recover discontinuities in the data while also removing noise and other artifacts. Total variation regularization has been…

Analysis of PDEs · Mathematics 2018-08-15 Linan Zhang , Hayden Schaeffer

Total variation regularization based on the l1 norm is ubiquitous in image reconstruction. However, the resulting reconstructions are not always as sparse in the edge domain as desired. Iteratively reweighted methods provide some…

Image and Video Processing · Electrical Eng. & Systems 2022-04-01 Victor Churchill , Rick Archibald , Anne Gelb

In this work, we propose and analyse a weak Galerkin method for the electrical impedance tomography based on a bounded variation regularization. We use the complete electrode model as the forward system that is approximated by a weak…

Numerical Analysis · Mathematics 2023-10-03 Ying Liang , Jun Zou

Reconstructing cardiac electrical activity from body surface electric potential measurements results in the severely ill-posed inverse problem in electrocardiography. Many different regularization approaches have been proposed to improve…

Numerical Analysis · Mathematics 2025-11-04 Manuel Haas , Thomas Grandits , Thomas Pinetz , Thomas Beiert , Simone Pezzuto , Alexander Effland

Image reconstruction of EIT mathematically is a typical nonlinear and severely ill-posed inverse problem. Appropriate priors or penalties are required to enable the reconstruction. The commonly used L2-norm can enforce the stability to…

Numerical Analysis · Mathematics 2018-03-13 Jing Wang , Bo Han , Wei Wang

In this contribution, we are concerned with model order reduction in the context of iterative regularization methods for the solution of inverse problems arising from parameter identification in elliptic partial differential equations. Such…

Numerical Analysis · Mathematics 2024-10-14 Michael Kartmann , Tim Keil , Mario Ohlberger , Stefan Volkwein , Barbara Kaltenbacher

Electrical capacitance tomography (ECT) has been investigated in many fields due to its advantages of being non-invasive and low cost. Sparse algorithms with l1-norm regularization are used to reduce the smoothing effect and obtain sharp…

Signal Processing · Electrical Eng. & Systems 2017-11-08 Jiaoxuan Chen , Maomao Zhang , Yi Li

In this paper, we propose a certified reduced basis (RB) method for quasilinear elliptic problems together with its application to nonlinear magnetostatics equations, where the later model permanent magnet synchronous motors (PMSM). The…

Numerical Analysis · Mathematics 2020-07-03 Michael Hinze , Denis Korolev

In this paper, we consider a backward problem for a time-space fractional diffusion process. For this problem, we propose to construct the initial data by minimizing data residual error in fourier space domain and variable total variation…

Numerical Analysis · Mathematics 2016-05-24 Junxiong Jia , Jigen Peng , Jinghuai Gao , Yujiao Li

A qualitative comparison of total variation like penalties (total variation, Huber variant of total variation, total generalized variation, ...) is made in the context of global seismic tomography. Both penalized and constrained…

Geophysics · Physics 2012-04-09 Ignace Loris , Caroline Verhoeven

High radiation dose in CT scans increases a lifetime risk of cancer and has become a major clinical concern. Recently, iterative reconstruction algorithms with Total Variation (TV) regularization have been developed to reconstruct CT images…

Medical Physics · Physics 2015-05-19 Zhen Tian , Xun Jia , Kehong Yuan , Tinsu Pan , Steve B. Jiang

Image restoration is one of the most fundamental issues in imaging science. Total variation (TV) regularization is widely used in image restoration problems for its capability to preserve edges. In the literature, however, it is also well…

Computer Vision and Pattern Recognition · Computer Science 2013-10-22 Jun Liu , Ting-Zhu Huang , Ivan W. Selesnick , Xiao-Guang Lv , Po-Yu Chen

In a number of tomographic applications, data cannot be fully acquired, resulting in a severely underdetermined image reconstruction. In such cases, conventional methods lead to reconstructions with significant artifacts. To overcome these…

Numerical Analysis · Mathematics 2023-06-21 Simon Göppel , Jürgen Frikel , Markus Haltmeier

We consider the imaging problem of the reconstruction of a three-dimensional object via optical diffraction tomography under the assumptions of the Born approximation. Our focus lies in the situation that a rigid object performs an…

Numerical Analysis · Mathematics 2024-07-11 Robert Beinert , Michael Quellmalz

Inspired by the first-order method of Malitsky and Pock, we propose a new variational framework for compressed MR image reconstruction which introduces the application of a rotation-invariant discretization of total variation functional…

Image and Video Processing · Electrical Eng. & Systems 2020-04-22 Erfan Ebrahim Esfahani , Alireza Hosseini

In this paper we the formulation of inverse problems as constrained minimization problems and their iterative solution by gradient or Newton type. We carry out a convergence analysis in the sense of regularization methods and discuss…

Numerical Analysis · Mathematics 2021-01-15 Barbara Kaltenbacher , Kha Van Huynh