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The determination of solutions of many inverse problems usually requires a set of measurements which leads to solving systems of ill-posed equations. In this paper we propose the Landweber iteration of Kaczmarz type with general uniformly…

Numerical Analysis · Mathematics 2013-07-17 Qinian Jin , Wei Wang

We are concerned with the reconstruction of a sound-soft obstacle using far field measurements of the scattered waves associated with incident plane waves sent from one direction but at multiple frequencies. We define, for each frequency,…

Numerical Analysis · Mathematics 2013-10-22 Mourad Sini , Nguyen Trung Thành

The general method to obtain solutions of the Maxwellian equations from scalar representatives is developed and applied to the diffraction of electromagnetic waves. Kirchhoff's integral is modified to provide explicit expressions for these…

Optics · Physics 2019-03-27 Ulrich Brosa

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

This paper presents an iterative inversion algorithm for computed tomography image reconstruction that performs well in terms of accuracy and speed using limited data. The computational method combines an image domain technique and…

Image and Video Processing · Electrical Eng. & Systems 2019-01-17 Victor Churchill , Anne Gelb

Multi-wave inverse problems are indirect imaging methods using the interaction of two different imaging modalities. One brings spatial accuracy, and the other contrast sensitivity. The inversion method typically involve two steps. The first…

Analysis of PDEs · Mathematics 2023-01-05 Yves Capdeboscq , Tianrui Dai

Ultrasound image degradation in the human body is complex and occurs due to the distortion of the wave as it propagates to and from the target. Here, we establish a simulation based framework that deconstructs the sources of image…

Medical Physics · Physics 2021-06-29 Danai Eleni Soulioti , Francisco Santibanez , Gianmarco Pinton

Maximum-likelihood methods are applied to the problem of absorption tomography. The reconstruction is done with the help of an iterative algorithm. We show how the statistics of the illuminating beam can be incorporated into the…

Data Analysis, Statistics and Probability · Physics 2009-11-07 J. Rehacek , Z. Hradil , M. Zawisky , W. Treimer , M. Strobl

An iterative algorithm is adopted to construct approximate representations of matrices describing the scattering properties of arbitrary objects. The method is based on the implicit evaluation of scattering responses from iteratively…

Computational Physics · Physics 2023-04-19 Johan Lundgren , Kurt Schab , Miloslav Capek , Mats Gustafsson , Lukas Jelinek

Doppler reflectometry spatial and wavenumber resolution is analyzed within the framework of the linear Born approximation in slab plasma model. Explicit expression for its signal backscattering spectrum is obtained in terms of wavenumber…

Plasma Physics · Physics 2007-05-23 Alexander Surkov , Evgeniy Gusakov

A numerical solution to the problem of wave scattering by many small particles is studied under the assumption k<<1, d>>a, where a is the size of the particles and d is the distance between the neighboring particles. Impedance boundary…

Computational Physics · Physics 2012-06-18 M. I. Andriychuk , A. G. Ramm

Convergence problems in coupled-cluster iterations are discussed, and a new iteration scheme is proposed. Whereas the Jacobi method inverts only the diagonal part of the large matrix of equation coefficients, we invert a matrix which also…

Chemical Physics · Physics 2009-11-06 N. Mosyagin , E. Eliav , U. Kaldor

Recent advances in twistor theory are applied to geometric optics in ${\Bbb{R}}^3$. The general formulae for reflection of a wavefront in a surface are derived and in three special cases explicit descriptions are provided: when the…

Differential Geometry · Mathematics 2021-11-15 Brendan Guilfoyle , Wilhelm Klingenberg

The map-making process of Cosmic Microwave Background data involves linear inversion problems which cannot be performed by a brute force approach for the large timelines of most modern experiments. We present optimal iterative map-making…

Astrophysics · Physics 2010-12-13 Xavier Dupac

We study an inverse scattering problem for a generic hyperbolic system of equations with an unknown coefficient called the reflectivity. The solution of the system models waves (sound, electromagnetic or elastic), and the reflectivity…

Numerical Analysis · Mathematics 2020-02-03 Liliana Borcea , Vladimir Druskin , Alexander V. Mamonov , Mikhail Zaslavsky , Jörn Zimmerling

In this work, the lattice Boltzmann method (LBM) is assessed as a time-domain numerical approach for electromagnetic wave scattering. Owing to its explicit formulation and suitability for parallel computation on structured grids, LBM…

Optics · Physics 2026-04-08 Mohd. Meraj Khan , Sumesh P. Thampi , Anubhab Roy

An imaging system is proposed for matter-wave functions that is based on producing a quadratic phase modulation on the wavefunction of a charged particle, analogous to that produced by a space or time lens. The modulation is produced by…

Quantum Physics · Physics 2020-10-28 Brian H. Kolner

Photometric Stereo methods seek to reconstruct the 3d shape of an object from motionless images obtained with varying illumination. Most existing methods solve a restricted problem where the physical reflectance model, such as Lambertian…

Computer Vision and Pattern Recognition · Computer Science 2021-10-06 Ofer Bartal , Nati Ofir , Yaron Lipman , Ronen Basri

In a Hilbert space, we study the strong convergence of alternating projections between two inconsistent affine subspaces with varying relaxation on one side. New convergence results are obtained by seeing the alternating projections as a…

Functional Analysis · Mathematics 2025-07-15 Nguyen T. Thao

Theoretical and computational study of reflection and refraction of electromagnetic waves with $p$-polarized and normal incidence electric wave amplitude vector on anisotropic, inhomogeneous and linear medium has been done. The medium used…

Optics · Physics 2012-03-09 Andri S. Husein , Roniyus MS , Sri W. Suciyati
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