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In this paper, we present a novel reconstruction method for diffuse optical spectroscopic imaging with a commonly used tissue model of optical absorption and scattering. It is based on linearization and group sparsity, which allows…

Numerical Analysis · Mathematics 2019-03-06 Habib Ammari , Bangti Jin , Wenlong Zhang

A statistical method for reconstructing large scale structure behind the Zone of Avoidance is presented. It also corrects for shot-noise and for redshift distortion in galaxy surveys. The galaxy distribution is expanded in an orthogonal set…

Astrophysics · Physics 2007-05-23 Ofer Lahav

The problem of the one-exciton absorption spectrum is considered for the lattice of two-level interacting atoms whose initial energy splitting depends on the coordinate. It is shown that for some types of interatomic interaction, this…

Disordered Systems and Neural Networks · Physics 2007-05-23 G. G. Kozlov

This paper analyzes the reconstruction of diffusion and absorption parameters in an elliptic equation from knowledge of internal data. In the application of photo-acoustics, the internal data are the amount of thermal energy deposited by…

Analysis of PDEs · Mathematics 2015-05-14 Guillaume Bal , Gunther Uhlmann

Particle shape and aggregation have a strong influence on the spectral profiles of infrared phonon bands of solid dust grains. In this paper, we use a discrete dipole approximation, a cluster-of-spheres code following the Gerardy-Ausloos…

Astrophysics · Physics 2007-05-23 Anja C. Andersen , Harald Mutschke , Thomas Posch

Imaging through a single optical fiber offers attractive possibilities in many applications such as microendoscopy or remote sensing. However, the direct transmission of an image through an optical fiber is difficult because spatial…

Optics · Physics 2015-05-29 Roman Barankov , Jerome Mertz

Reliable control of the deposition process of optical films and coatings frequently requires monitoring of the refractive index profile throughout the layer. In the present work a simple in situ approach is proposed which uses a WKBJ matrix…

Optics · Physics 2009-10-31 Daniel Poitras , Ludvik Martinu

We show that an arbitrary spatial distribution of complex refractive index inside an object can be exactly represented as a sum of two "monomorphous" complex distributions, i.e. the distributions with the ratios of the real part to the…

Medical Physics · Physics 2015-12-09 T. E. Gureyev , Ya. I. Nesterets

We introduce an absorption imaging technique for ultracold gases that suppresses interference fringes and coherence-induced artifacts by reducing the transverse spatial coherence of the imaging light. The method preserves the narrow…

Quantum Gases · Physics 2026-02-16 Julia Fekete , Poppy Joshi , Peter Krüger , Fedja Oručević

We consider the inverse scattering problem of retrieving the structural parameters of a stratified medium consisting of dispersive materials, given knowledge of the complex reflection coefficient in a finite frequency range. It is shown…

Optics · Physics 2012-08-23 Johannes Skaar , Magnus W. Haakestad

Direct imaging methods recover the presence, position, and shape of the unknown obstacles in time-harmonic inverse scattering without a priori knowledge of either the physical properties or the number of disconnected components of the…

Analysis of PDEs · Mathematics 2023-11-29 General Ozochiawaeze

Spectra of late-type stars are usually analyzed with static model atmospheres in local thermodynamic equilibrium (LTE) and a homogeneous plane-parallel or spherically symmetric geometry. The energy balance requires particular attention, as…

Astrophysics · Physics 2009-11-06 Carlos Allende Prieto , Paul S. Barklem , Martin Asplund , Basilio Ruiz Cobo

Optical interferometers provide multiple wavelength measurements. In order to fully exploit the spectral and spatial resolution of these instruments, new algorithms for image reconstruction have to be developed. Early attempts to deal with…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 Éric Thiébaut , Ferréol Soulez , Loïc Denis

Upcoming space-based coronagraphic instruments in the next decade will perform reflected light spectroscopy and photometry of cool, directly imaged extrasolar giant planets. We are developing a new atmospheric retrieval methodology to help…

Instrumentation and Methods for Astrophysics · Physics 2016-12-14 Roxana E. Lupu , Mark S. Marley , Nikole Lewis , Michael Line , Wesley A. Traub , Kevin Zahnle

Many applications of electromagnetic scattering involve particles immersed in an absorbing rather than lossless medium, thereby making the conventional scattering theory potentially inapplicable. To analyze this issue quantitatively, we…

Optics · Physics 2018-09-05 M. I. Mishchenko , J. M. Dlugach

The problem to be studied in this work is within the context of coefficient identification problems for the wave equation. More precisely, we consider the problem of reconstruction of the refractive index (or equivalently, the dielectric…

Mathematical Physics · Physics 2013-06-14 Nguyen Trung Thành , Larisa Beilina , Michael V. Klibanov , Michael A. Fiddy

It has been shown that spectroscopy of transiting extrasolar planets can potentially provide a wealth of information about their atmospheres. Herein, we set up the inverse problem in spectroscopic retrieval. We use non-linear optimal…

Earth and Planetary Astrophysics · Physics 2015-06-03 M. R. Line , X. Zhang , G. Vaisht , P. Chen , V. Natraj , P. Chen , Y. L. Yung

Photon transport through a diffusing slab can be described by the radiative transfer equation (RTE). When the slab is highly scattering and weakly absorbing, the RTE simplifies to the diffusion equation. In this paper, an inverse diffusion…

Molecules and particles make up $\sim 40 - 70\%$ of carbon in the interstellar medium, yet the exact chemical structure of these constituents remains unknown. We present carbon K-shell absorption spectroscopy of the Galactic Interstellar…

High Energy Astrophysical Phenomena · Physics 2023-05-31 John Staunton , Frits Paerels

We present a physics-based inverse rendering method that learns the illumination, geometry, and materials of a scene from posed multi-view RGB images. To model the illumination of a scene, existing inverse rendering works either completely…

Computer Vision and Pattern Recognition · Computer Science 2023-12-04 Youming Deng , Xueting Li , Sifei Liu , Ming-Hsuan Yang
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