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We propose a tomographic method to reconstruct the optical properties of a highly-scattering medium from incoherent acousto-optic measurements. The method is based on the solution to an inverse problem for the diffusion equation and makes…

Optics · Physics 2015-05-14 Guillaume Bal , John C Schotland

A new measuring technique dedicated to bubble velocity and size measurements in complex bubbly flows such as those occurring in bubble columns is proposed. This sensor combines the phase detection capability of a conical optical fiber, with…

Fluid Dynamics · Physics 2021-09-17 Anthony Lefebvre , Yann Mezui , Martin Obligado , Stéphane Gluck , Alain Cartellier

We propose a time-domain boundary integral method to model linear wave propagation with refractive, focusing, and Doppler effects arising from medium heterogeneities and moving obstacles. In contrast to existing techniques, our method…

Numerical Analysis · Mathematics 2026-05-13 Raaghav Ramani

The non-uniform surface temperature distribution of rotating active stars is routinely mapped with the Doppler Imaging technique. Inhomogeneities in the surface produce features in high-resolution spectroscopic observations that shift in…

Instrumentation and Methods for Astrophysics · Physics 2022-02-23 A. Asensio Ramos , C. Diaz Baso , O. Kochukhov

Doppler lensing is the apparent change in object size and magnitude due to peculiar velocities. Objects falling into an overdensity appear larger on its near side, and smaller on its far side, than typical objects at the same redshifts.…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-03 David J. Bacon , Sambatra Andrianomena , Chris Clarkson , Krzysztof Bolejko , Roy Maartens

We demonstrate two techniques for studying the features of three-level systems driven by two lasers (called control and probe), when the transitions are Doppler broadened as in room-temperature vapor. For $\Lambda$-type systems, the probe…

Optics · Physics 2007-05-23 Umakant D. Rapol , Vasant Natarajan

Cataclysmic Variables (CVs) are close binary systems where mass is transferred from a red dwarf star to a white dwarf star via an accretion disk. The flickering is observed as stochastic variations in the emitted radiation both in the…

Astrophysics · Physics 2009-11-11 Fabiola Mariana A. Ribeiro , Marcos P. Diaz

Doppler Imaging produces 2D global maps of rotating objects using high-dispersion spectroscopy. When applied to brown dwarfs and extrasolar planets, this technique can constrain global atmospheric dynamics and/or magnetic effects on these…

Solar and Stellar Astrophysics · Physics 2014-07-02 Ian J. M. Crossfield

Doppler spectroscopy is a powerful tool for discovering and characterizing exoplanets. For decades, the standard approach to extracting radial velocities (RVs) has been to cross-correlate observed spectra with a weighted template mask.…

Earth and Planetary Astrophysics · Physics 2020-02-05 Vinesh M. Rajpaul , Suzanne Aigrain , Lars A. Buchhave

Spectral Doppler ultrasound imaging allows visualizing blood flow by estimating its velocity distribution over time. Duplex ultrasound is a modality in which an ultrasound system is used for displaying simultaneously both B-mode images and…

Information Theory · Computer Science 2018-08-03 Regev Cohen , Yonina C. Eldar

We have found the first convincing evidence for spiral structure in the accretion disc of a close binary. The eclipsing dwarf nova binary IP Peg, observed during the end phase of a rise to outburst, shows strong Balmer and Helium emission…

Astrophysics · Physics 2016-01-13 D. Steeghs , E. T. Harlaftis , Keith Horne

The Doppler shifts of optical emission lines which have been scattered by surrounding dust and electrons can provide useful information about the kinematics, geometry and physical conditions of astrophysical flows. In principle, the…

Astrophysics · Physics 2007-05-23 W. J. Henney

Optical diffraction tomography is an indispensable tool for studying objects in three-dimensions due to its ability to accurately reconstruct scattering objects. Until now this technique has been limited to coherent light because spatial…

We introduce Doppler time-of-flight (D-ToF) rendering, an extension of ToF rendering for dynamic scenes, with applications in simulating D-ToF cameras. D-ToF cameras use high-frequency modulation of illumination and exposure, and measure…

Graphics · Computer Science 2023-10-06 Juhyeon Kim , Wojciech Jarosz , Ioannis Gkioulekas , Adithya Pediredla

This paper is concerned with inverse scattering of plane waves by a locally perturbed infinite plane (which is called a locally rough surface) with the modulus of the total-field data (also called the phaseless near-field data) at a fixed…

Numerical Analysis · Mathematics 2018-08-28 Xiaoxu Xu , Bo Zhang , Haiwen Zhang

A review is given on aspects of indirect imaging techniques in X-ray binaries which are used as diagnostics tools for probing the X-ray dominated accretion disc physics. These techniques utilize observed properties such as the emission line…

Astrophysics · Physics 2007-05-23 Emilios T. Harlaftis

Traditionally, measuring the center-of-mass (c.m.) velocity of an atomic ensemble relies on measuring the Doppler shift of the absorption spectrum of single atoms in the ensemble. Mapping out the velocity distribution of the ensemble is…

Atomic Physics · Physics 2020-03-10 Zilong Chen , Hong Ming Lim , Chang Huang , Rainer Dumke , Shau-Yu Lan

Fundamental to the analysis of nonlinear relativistic motion is the precise characterization of the induced dynamic Doppler effects. In this work, we analyze the electromagnetic signals observed by non-inertial receivers using two…

Mathematical Physics · Physics 2026-03-27 Bryce M. Barclay , Alex Mahalov

Stellar magnetic activity produces time-varying distortions in the photospheric line profiles of solar-type stars. These lead to systematic errors in high-precision radial-velocity measurements, which limit efforts to discover and measure…

Many edge and contour detection algorithms give a soft-value as an output and the final binary map is commonly obtained by applying an optimal threshold. In this paper, we propose a novel method to detect image contours from the extracted…

Computer Vision and Pattern Recognition · Computer Science 2021-05-12 Zahra Mousavi Kouzehkanan , Reshad Hosseini , Babak Nadjar Araabi