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This work is concerned with fan- and cone-beam computed tomography with circular source trajectory, where the reconstruction inverse problem requires an accurate knowledge of source, detector and rotational axis relative positions and…

Numerical Analysis · Mathematics 2024-05-09 Patricio Guerrero , Simon Bellens , Ricardo Santander , Wim Dewulf

Iterative methods for tomographic image reconstruction have great potential for enabling high quality imaging from low-dose projection data. The computational burden of iterative reconstruction algorithms, however, has been an impediment in…

Image and Video Processing · Electrical Eng. & Systems 2019-07-25 Kai Zhang , Alireza Entezari

In x-ray coherent scatter tomography, tomographic measurements of the forward scatter distribution are used to infer scatter densities within a volume. A radiopaque 2D pattern placed between the object and the detector array enables the…

A novel formulation of the hyperspectral broadband phase retrieval is developed for the scenario where both object and modulation phase masks are spectrally varying. The proposed algorithm is based on a complex domain version of the…

Image and Video Processing · Electrical Eng. & Systems 2021-05-18 Vladimir Katkovnik , Igor Shevkunov , Karen Egiazarian

This article extends the author's past work [Inv. Probl. Imaging, 10:2 (2016), 433--459] to attenuated X-ray transforms, where the attenuation is complex-valued and only depends on position. We give a positive and constructive answer to the…

Analysis of PDEs · Mathematics 2017-11-03 François Monard

Based on a plane-wave expansion of the observation data in quasi-planar multi-static scattering scenarios, an improved formalism for image creation utilizing back-projection in the spatial domain is derived. The underlying integral…

Image and Video Processing · Electrical Eng. & Systems 2026-03-03 Matthias M. Saurer , Marius Brinkmann , Han Na , Quanfeng Wang , Thomas Eibert

Fast image reconstruction techniques are becoming important with the increasing number of scientific cases in high resolution micro and nano tomography. The processing of the large scale three-dimensional data demands new mathematical tools…

Numerical Analysis · Mathematics 2016-08-15 Nikolay Koshev , Elias S. Helou , Eduardo X. Miqueles

We consider a troublesome form of non-isoplanatism in synthesis radio telescopes: non-coplanar baselines. We present a novel interpretation of the non-coplanar baselines effect as being due to differential Fresnel diffraction in the…

Astrophysics · Physics 2009-11-13 T. J. Cornwell , K. Golap , S. Bhatnagar

In this paper, we derive a neural network architecture based on an analytical formulation of the parallel-to-fan beam conversion problem following the concept of precision learning. The network allows to learn the unknown operators in this…

Computer Vision and Pattern Recognition · Computer Science 2018-10-24 Christopher Syben , Bernhard Stimpel , Jonathan Lommen , Tobias Würfl , Arnd Dörfler , Andreas Maier

The problem of image reconstruction in thermoacoustic tomography requires inversion of a generalized Radon transform, which integrates the unknown function over circles in 2D or spheres in 3D. The paper investigates implementation of the…

Numerical Analysis · Mathematics 2007-05-23 Gaik Ambartsoumian , Sarah K. Patch

The problem of approximating a sampled function using sums of a fixed number of complex exponentials is considered. We use alternating projections between fixed rank matrices and Hankel matrices to obtain such an approximation. Convergence,…

Numerical Analysis · Mathematics 2011-07-12 Fredrik Andersson , Marcus Carlsson , Per-Anders Ivert

ThermoAcoustic Tomography (TAT) is a promising, non invasive, medical imaging technique whose inverse problem can be formulated as an initial condition reconstruction. In this paper, we introduce a new algorithm originally designed to…

Optimization and Control · Mathematics 2011-12-06 Xavier Bonnefond , Sébastien Marinesque

Photo-Acoustic Tomography (PAT) can reconstruct a distribution of optical absorbers acting as instantaneous sound sources in subcutaneous microvasculature of a human breast. Adjoint methods for PAT, typically Time-Reversal (TR) and…

Numerical Analysis · Mathematics 2018-06-25 Hongxiang Lin , Takashi Azuma , Mehmet Burcin Unlu , Shu Takagi

We propose a thorough analysis of the tensor tomography problem on the Euclidean unit disk parameterized in fan-beam coordinates. This includes, for the inversion of the Radon transform over functions, using another range characterization…

Analysis of PDEs · Mathematics 2016-03-25 Francois Monard

This article is concerned with tensor field tomography in a fairly general setting, that takes refraction, attenuation and time-dependence of tensor fields into account. The mathematical model is given by attenuated ray transforms of the…

Numerical Analysis · Mathematics 2026-01-19 Lukas Vierus , Thomas Schuster , Bernadette Hahn

We demonstrate the application of the recently introduced parametric projector operator technique to a calculation of the second order non-linear optical response of a multilevel molecular system. We derive a parametric quantum master…

Chemical Physics · Physics 2012-08-22 Jan Olsina , Tomas Mancal

Photoacoustic Tomography (PAT) is an emerging biomedical "imaging from coupled physics" technique, in which the image contrast is due to optical absorption, but the information is carried to the surface of the tissue as ultrasound pulses.…

Numerical Analysis · Mathematics 2016-11-03 Simon R. Arridge , Marta M. Betcke , Ben T. Cox , Felix Lucka , Brad E. Treeby

A generalized cross-validation approach to estimate the reconstruction filter bandwidth in two-dimensional Filtered Backprojection is presented. The method writes the reconstruction equation in equivalent backprojected filtering form,…

Methodology · Statistics 2019-10-02 Ranjan Maitra

The inverse source problem arising in photoacoustic tomography and in several other coupled-physics modalities is frequently solved by iterative algorithms. Such algorithms are based on the minimization of a certain cost functional. In…

Image and Video Processing · Electrical Eng. & Systems 2025-10-29 Andreas Hauptmann , Leonid Kunyansky , Jenni Poimala

In this paper, we first present an arc based algorithm for fan-beam computed tomography (CT) reconstruction via applying Katsevich's helical CT formula to 2D fan-beam CT reconstruction. Then, we propose a new weighting function to deal with…

Image and Video Processing · Electrical Eng. & Systems 2021-01-07 Wei Wang , Xiang-Gen Xia , Chuanjiang He , Zemin Ren , Jian Lu , Tianfu Wang , Baiying Lei
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