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Regularisation is commonly used in iterative methods for solving imaging inverse problems. Many algorithms involve the evaluation of the proximal operator of the regularisation term in every iteration, leading to a significant computational…

Numerical Analysis · Mathematics 2024-11-04 Evangelos Papoutsellis , Zeljko Kereta , Kostas Papafitsoros

Inverse medium scattering is an ill-posed, nonlinear wave-based imaging problem arising in medical imaging, remote sensing, and non-destructive testing. Machine learning (ML) methods offer increased inference speed and flexibility in…

Computational Physics · Physics 2025-12-12 Olivia Tsang , Owen Melia , Vasileios Charisopoulos , Jeremy Hoskins , Yuehaw Khoo , Rebecca Willett

In this article, we propose a novel regularization method for a class of nonlinear inverse problems that is inspired by an application in quantitative magnetic resonance imaging (qMRI). The latter is a special instance of a general…

Optimization and Control · Mathematics 2025-06-16 Guozhi Dong , Michael Hintermüller , Clemens Sirotenko

The cosmic microwave background (CMB) is a significant source of knowledge about the origin and evolution of our universe. However, observations of the CMB are contaminated by foreground emissions, obscuring the CMB signal and reducing its…

Machine Learning · Computer Science 2023-02-27 Jadie Adams , Steven Lu , Krzysztof M. Gorski , Graca Rocha , Kiri L. Wagstaff

There remains an important need for the development of image reconstruction methods that can produce diagnostically useful images from undersampled measurements. In magnetic resonance imaging (MRI), for example, such methods can facilitate…

Image and Video Processing · Electrical Eng. & Systems 2021-06-28 Varun A. Kelkar , Sayantan Bhadra , Mark A. Anastasio

We study an inverse scattering problem for Maxwell's equations in terminating waveguides, where localized reflectors are to be imaged using a remote array of sensors. The array probes the waveguide with waves and measures the scattered…

Numerical Analysis · Mathematics 2015-10-27 Liliana Borcea , Dinh-Liem Nguyen

The translation of an early (1957), Russian article on the development of x-ray computed tomography is provided. The article demonstrates a principle possibility of determining the local attenuation coefficient in every element of a…

History and Philosophy of Physics · Physics 2020-01-14 Alex Gustschin

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 propose an image reconstruction method for an X-ray telescope system with an angular resolution booster proposed by Maeda et al.(2018). The system consists of double multi-grid masks in front of an X-ray mirror and an off-focused…

Instrumentation and Methods for Astrophysics · Physics 2019-01-16 Mikio Morii , Shiro Ikeda , Yoshitomo Maeda

Classical methods for X-ray computed tomography are based on the assumption that the X-ray source intensity is known, but in practice, the intensity is measured and hence uncertain. Under normal operating conditions, when the exposure time…

Numerical Analysis · Mathematics 2017-07-17 Hari Om Aggrawal , Martin Skovgaard Andersen , Sean Rose , Emil Y. Sidky

The field of medical image reconstruction has seen roughly four types of methods. The first type tended to be analytical methods, such as filtered back-projection (FBP) for X-ray computed tomography (CT) and the inverse Fourier transform…

Image and Video Processing · Electrical Eng. & Systems 2019-08-19 Saiprasad Ravishankar , Jong Chul Ye , Jeffrey A. Fessler

The study of the Cosmic Microwave Background (CMB) lensing potential has established itself by now as a robust way of probing the physics of large-scale structure growth. The most common estimators of the lensing potential are derived under…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 Dominic Beck , Giulio Fabbian , Josquin Errard

The use of ray projections to reconstruct images is a common technique in medical imaging. Dealing with incomplete data is particularly important when a patient is vulnerable to potentially damaging radiation or is unable to cope with the…

Neural and Evolutionary Computing · Computer Science 2024-06-04 Mohammad Majid al-Rifaie , Tim Blackwell

We are concerned with the inverse scattering problem of extracting the geometric structures of an unknown/inaccessible inhomogeneous medium by using the corresponding acoustic far-field measurement. Using the intrinsic geometric properties…

Analysis of PDEs · Mathematics 2017-06-15 Jingzhi Li , Xiaofei Li , Hongyu Liu

We study iterative regularization for linear models, when the bias is convex but not necessarily strongly convex. We characterize the stability properties of a primal-dual gradient based approach, analyzing its convergence in the presence…

Machine Learning · Statistics 2020-10-30 Cesare Molinari , Mathurin Massias , Lorenzo Rosasco , Silvia Villa

We consider the problem of 3D shape recovery from ultra-fast motion-blurred images. While 3D reconstruction from static images has been extensively studied, recovering geometry from extreme motion-blurred images remains challenging. Such…

Computer Vision and Pattern Recognition · Computer Science 2026-02-10 Fei Yu , Shudan Guo , Shiqing Xin , Beibei Wang , Haisen Zhao , Wenzheng Chen

This paper focuses on the acousto-electromagnetic tomography, a recently introduced hybrid imaging technique. In a previous work, the reconstruction of the electric permittivity of the medium from internal data was achieved under the Born…

Analysis of PDEs · Mathematics 2019-04-04 Giovanni S. Alberti , Habib Ammari , Kaixi Ruan

Gravitational lensing of distant galaxies can be exploited to infer the convergence field as a function of angular position on the sky. The statistics of this field, much like that of the cosmic microwave background (CMB), can be studied to…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-07 Hee-Jong Seo , Masanori Sato , Scott Dodelson , Bhuvnesh Jain , Masahiro Takada

Tomographic image reconstruction is relevant for many medical imaging modalities including X-ray, ultrasound (US) computed tomography (CT) and photoacoustics, for which the access to full angular range tomographic projections might be not…

Image and Video Processing · Electrical Eng. & Systems 2019-06-14 Valery Vishnevskiy , Richard Rau , Orcun Goksel

In this paper we investigate all-at-once versus reduced regularization of dynamic inverse problems on finite time intervals $(0,T)$. In doing so, we concentrate on iterative methods and nonlinear problems, since they have already been shown…

Numerical Analysis · Mathematics 2019-10-16 Barbara Kaltenbacher
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