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We present the solution to an inverse problem arising in the context of finding a distribution function for a specific collisionless plasma equilibrium. The inverse problem involves the solution of two integral equations, each having the…

Plasma Physics · Physics 2016-06-08 O. Allanson , T. Neukirch , S. Troscheit , F. Wilson

We investigate departures from LTE in the line formation of Fe for a number of well-studied late-type stars in different evolutionary stages. A new model of Fe atom was constructed from the most up-to-date theoretical and experimental…

Solar and Stellar Astrophysics · Physics 2015-06-05 Maria Bergemann , Karin Lind , Remo Collet , Zazralt Magic , Martin Asplund

We propose a method to reconstruct the optical properties of a scattering medium with subwavelength resolution. The method is based on the solution to the inverse scattering problem with photoactivated internal sources. Numerical…

Optics · Physics 2018-08-01 Anna C. Gilbert , Howard W. Levinson , John C. Schotland

We consider the problem of reconstructing the shape of an impenetrable sound-soft obstacle from scattering measurements. The input data is assumed to be the far-field pattern generated when a plane wave impinges on an unknown obstacle from…

Numerical Analysis · Mathematics 2015-05-28 Carlos Borges , Leslie Greengard

The perspective-$n$-point (P$n$P) problem is important for robotic pose estimation. It is well studied for optical cameras, but research is lacking for 2D forward-looking sonar (FLS) in underwater scenarios due to the vastly different…

Robotics · Computer Science 2025-04-11 Jiayi Su , Jingyu Qian , Liuqing Yang , Yufan Yuan , Yanbing Fu , Jie Wu , Yan Wei , Fengzhong Qu

A rigorous mathematical model and an efficient computational method are proposed to solving the inverse elastic surface scattering problem which arises from the near-field imaging of periodic structures. We demonstrate how an enhanced…

Analysis of PDEs · Mathematics 2017-12-08 Huaian Diao , Peijun Li , Xiaokai Yuan

We present a novel convolutional neural network architecture for photometric stereo (Woodham, 1980), a problem of recovering 3D object surface normals from multiple images observed under varying illuminations. Despite its long history in…

Computer Vision and Pattern Recognition · Computer Science 2018-05-30 Tatsunori Taniai , Takanori Maehara

A 3-D inverse medium problem in the frequency domain is considered. Another name for this problem is Coefficient Inverse Problem. The goal is to reconstruct spatially distributed dielectric constants from scattering data. Potential…

Numerical Analysis · Mathematics 2016-05-23 Michael V. Klibanov , Hui Liu , Loc H. Nguyen

We provide a new algorithm for the treatment of inverse problems which combines the traditional SVD inversion with an appropriate thresholding technique in a well chosen new basis. Our goal is to devise an inversion procedure which has the…

Statistics Theory · Mathematics 2016-08-14 Gérard Kerkyacharian , Pencho Petrushev , Dominique Picard , Thomas Willer

It is of great interest to solve the inverse problem of stationary radiative transport equation (RTE) in optical tomography. The standard way is to formulate the inverse problem into an optimization problem, but the bottleneck is that one…

Numerical Analysis · Mathematics 2024-01-09 Jingyi Fu , Min Tang

In this study, we introduce a novel approach for deriving the solution of the ideal force-free steady-state pulsar magnetosphere in three dimensions. Our method involves partitioning the magnetosphere into the regions of closed and open…

High Energy Astrophysical Phenomena · Physics 2024-01-17 Ioannis Dimitropoulos , Ioannis Contopoulos , Vassilis Mpisketzis , Evangelos Chaniadakis

Numerous diffusion model (DM)-based methods have been proposed for solving inverse imaging problems. Among these, a recent line of work has demonstrated strong performance by formulating sampling as an optimization procedure that enforces…

Image and Video Processing · Electrical Eng. & Systems 2025-11-19 Shijun Liang , Ismail Alkhouri , Qing Qu , Rongrong Wang , Saiprasad Ravishankar

We propose a neural network-based algorithm for solving forward and inverse problems for partial differential equations in unsupervised fashion. The solution is approximated by a deep neural network which is the minimizer of a cost…

Machine Learning · Computer Science 2019-04-12 Leah Bar , Nir Sochen

This work focuses on 3D Radar imaging inverse problems. Current methods obtain undifferentiated results that suffer task-depended information retrieval loss and thus don't meet the task's specific demands well. For example, biased…

Signal Processing · Electrical Eng. & Systems 2022-11-29 Xu Zhan , Xiaoling Zhang , Mou Wang , Jun Shi , Shunjun Wei , Tianjiao Zeng

A solution to the inversion problem of scattering would offer aberration-free diffraction-limited 3D images without the resolution and depth-of-field limitations of lens-based tomographic systems. Powerful algorithms are increasingly being…

Heterogeneous anisotropic diffusion problems arise in the various areas of science and engineering including plasma physics, petroleum engineering, and image processing. Standard numerical methods can produce spurious oscillations when they…

Numerical Analysis · Mathematics 2015-05-18 Xianping Li , Weizhang Huang

Lensless imaging has emerged as a potential solution towards realizing ultra-miniature cameras by eschewing the bulky lens in a traditional camera. Without a focusing lens, the lensless cameras rely on computational algorithms to recover…

Image and Video Processing · Electrical Eng. & Systems 2020-10-30 Salman S. Khan , Varun Sundar , Vivek Boominathan , Ashok Veeraraghavan , Kaushik Mitra

An inverse scattering problem is formulated for reconstructing optical properties of biological tissues. A recursive linearization algorithm is used to solve the inverse scattering problem. We employed the idea of finite element boundary…

Numerical Analysis · Mathematics 2014-04-30 Ying Li

In tomographic reconstruction, the goal is to reconstruct an unknown object from a collection of line integrals. Given a complete sampling of such line integrals for various angles and directions, explicit inverse formulas exist to…

Numerical Analysis · Mathematics 2018-01-18 Tristan van Leeuwen , Simon Maretzke , K. Joost Batenburg

This paper forms the second part of our study on how the neglect of NLTE conditions in the formation of Fe I 6301.5 A and the 6302.5 A lines influences the atmosphere obtained by inverting their profiles in LTE. The main cause of NLTE…

Solar and Stellar Astrophysics · Physics 2021-03-15 H. N. Smitha , R. Holzreuter , M. van Noort , S. K. Solanki
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