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Modern radio telescopes strongly rely on accurate computational electromagnetic tools for "beam" models. Especially for densely-packed aperture array radio telescopes, the only feasible way to produce accurate models of the individual…

Instrumentation and Methods for Astrophysics · Physics 2023-06-13 Pietro Bolli , David Davidson , Maria Grazia Labate , Stefan J. Wijnholds

We are investigating a new approach to modelling uncertainties in individual pixels of Very Long Baseline Interferometry (VLBI) intensity (Stokes I, Q, U) images. Comparison of distributions of our calculated uncertainties for model sources…

Astrophysics of Galaxies · Physics 2013-07-26 Colm P. Coughlan , Denise C. Gabuzda

We describe a scheme that characterizes the main beam and sidelobe in all Stokes parameters employing parameters that allow reconstruction of the complete beam patterns and, also, afford an easy way to see how the beam changes with azimuth,…

A statistical framework is presented for the study of the orthogonally polarized modes of radio pulsar emission via the covariances between the Stokes parameters. To accommodate the typically heavy-tailed distributions of single-pulse radio…

Instrumentation and Methods for Astrophysics · Physics 2017-02-07 Willem van Straten , Caterina Tiburzi

Optical phase-array antennas can be used to control not only the angular distribution but also the polarization of fluorescence from quantum emitters. The emission pattern of the resulting system is determined by the properties of the…

Optics · Physics 2015-12-02 Abbas Mohtashami , Clara I. Osorio , A. Femius Koenderink

It has been recently suggested that optical interferometers may not require a phase-stable optical link between the stations if instead sources of quantum-mechanically entangled pairs could be provided to them, enabling extra-long baselines…

We present techniques that improve the performance of asymmetric stabilizer codes in the presence of unital channels with unknown parameters. Our method estimates the channel parameters using information recovered from syndrome measurements…

Quantum Physics · Physics 2017-05-30 Jan Florjanczyk , Todd A. Brun

This paper is the third part of a trilogy dealing with the principles, performance and limitations of what I named "Telescope-Interferometers" (TIs). The basic idea consists in transforming one telescope into a Wavefront Error (WFE) sensing…

Optics · Physics 2011-05-17 Francois Henault

Radio interferometers must grapple with apparent fields of view that distort the true radio sky. These so-called 'A-term' distortions may be direction-, time- and baseline-dependent, and include effects like the primary beam and the…

Instrumentation and Methods for Astrophysics · Physics 2025-02-26 Torrance Hodgson

This paper develops a unifying framework for signal reconstruction from interferometric measurements that is broadly applicable to various applications of interferometry. In this framework, the problem of signal reconstruction in…

Information Theory · Computer Science 2017-07-03 Davood Mardani , George K. Atia , Ayman F. Abouraddy

High-contrast imaging for the detection and characterization of exoplanets relies on the instrument's capability to block out the light of the host star. Some current post-processing methods for calibrating out the residual speckles use…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Marie Ygouf , Laurent M. Mugnier , David Mouillet , Thierry Fusco , Jean-Luc Beuzit

Modern radio interferometers deliver large volumes of data containing high-sensitivity sky maps over wide fields-of-view. These large area observations can contain various and superposed structures such as point sources, extended objects,…

Instrumentation and Methods for Astrophysics · Physics 2025-12-05 Richard Fuchs , Jakob Knollmüller , Jakob Roth , Vincent Eberle , Philipp Frank , Torsten A. Enßlin , Lukas Heinrich

Intensity interferometry (II) exploits the second-order correlation to acquire the spatial frequency information of an object, which has been used to observe distant stars since 1950s. However, due to unreliability of employed imaging…

Image and Video Processing · Electrical Eng. & Systems 2017-12-08 Wentao Wang , Qi Han , Hui Chen , Yuan Yuan , Zhuo Xu

This is the second article in a series of two which report on a matrix approach for ultrasound imaging in heterogeneous media. This article describes the quantification and correction of aberration, i.e. the distortion of an image caused by…

Image and Video Processing · Electrical Eng. & Systems 2022-12-06 William Lambert , Laura A. Cobus , Justine Robin , Mathias Fink , Alexandre Aubry

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

To design semiconductor-based optical devices, the optical properties of the used semiconductor materials must be precisely measured over a large band. Transmission spectroscopy stands out as an inexpensive and widely available method for…

The paper presents formulation and solution for the problem of determination of spatial spectrum of artificial ionospheric irregularities from vertical HF radio sounding data on anomalous attenuation. The suggested method uses the…

Atmospheric and Oceanic Physics · Physics 2007-05-23 Nikolay A. Zabotin , Andrey G. Bronin , Gennady A. Zhbankov

Traditional phase-shifting interferometry technique cannot be used to measure time-varying phase distributions. But single shot techniques could resolve the problem. Many efforts have been made on the phase retrieval methods from a single…

Instrumentation and Detectors · Physics 2020-03-31 Lifa Hu , Wen Shena , Wenchao Ma , Dongting Hu , Xinyu Liu

We describe a method for removing ionospheric effects from single-frequency radio data a posteriori. This method is based on a theoretical climatological model developed by the USAF, which returns electron density as a function of position…

Astrophysics · Physics 2009-10-31 R. M. Campbell

We present a new way to solve the platform deformation problem of co-planar interferometers. The platform of a co-planar interferometer can be deformed due to driving forces and gravity. A deformed platform will induce extra components into…