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Extremely high data rates expected in next-generation radio interferometers necessitate a fast and robust way to process measurements in a big data context. Dimensionality reduction can alleviate computational load needed to process these…

Instrumentation and Methods for Astrophysics · Physics 2017-09-13 S. Vijay Kartik , Arwa Dabbech , Jean-Philippe Thiran , Yves Wiaux

Radio interferometry is a powerful technique for astronomical imaging. The theory of Compressed Sensing (CS) has been applied recently to the ill-posed inverse problem of recovering images from the measurements taken by radio…

Instrumentation and Methods for Astrophysics · Physics 2016-11-15 J. D. McEwen , Y. Wiaux

Interferometric phase (InPhase) imaging is an important part of many present-day coherent imaging technologies. Often in such imaging techniques, the acquired images, known as interferograms, suffer from two major degradations: 1) phase…

Signal Processing · Electrical Eng. & Systems 2019-11-25 Joshin P. Krishnan , Mário A. T. Figueiredo , José M. Bioucas-Dias

We present a new and highly efficient algorithm for computing a power spectrum made from evenly spaced data which combines the noise-reducing advantages of the weighted fit with the computational advantages of the Fast Fourier Transform…

Solar and Stellar Astrophysics · Physics 2015-05-28 S. T. Fletcher , A. -M. Broomhall , W. J. Chaplin , Y. Elsworth , R. New

In image and video coding applications, distortion has been traditionally measured using mean square error (MSE), which suggests the use of orthogonal transforms, such as the discrete cosine transform (DCT). Perceptual metrics such as…

Image and Video Processing · Electrical Eng. & Systems 2020-02-21 Keng-Shih Lu , Antonio Ortega , Debargha Mukherjee , Yue Chen

Antenna layout is an important design consideration for radio interferometers because it determines the quality of the snapshot point spread function (PSF, or array beam). This is particularly true for experiments targeting the 21 cm Epoch…

Interferometry can measure the shape or the material density of a system that could not be measured otherwise by recording the difference between the phase change of a signal and a reference phase. This difference is always between $-\pi$…

Plasma Physics · Physics 2022-10-20 Pierre-Alexandre Gourdain , Aidan Bachmann

Radio interferometric gain calibration can be biased by incomplete sky models and radio frequency interference, resulting in calibration artefacts that can restrict the dynamic range of the resulting images. It has been suggested that…

Instrumentation and Methods for Astrophysics · Physics 2019-10-21 Ulrich Armel Mbou Sob , Hertzog Landman Bester , Oleg Smirnov , Jonathan Kenyon , Trienko Grobler

Reconstruction of the point spread function (PSF) plays an important role in many areas of astronomy, including photometry, astrometry, galaxy morphology, and shear measurement. The atmospheric and instrumental effects are the two main…

Instrumentation and Methods for Astrophysics · Physics 2024-04-25 Pedro Alonso , Jun Zhang , Cong Liu

Diverse applications in photonics and microwave engineering require a means of measurement of the instantaneous frequency of a signal. A photonic implementation typically applies an interferometer equipped with three or more output ports to…

The paper reviews progress in imaging in radio interferometry for the period 1993-1996. Unlike an optical telescope, the basic measurements of a radio interferometer (correlations between antennas) are indirectly related to a sky brightness…

Astrophysics · Physics 2007-05-23 R. J. Sault , T. A. Oosterloo

Next-generation radio interferometers, such as the Square Kilometre Array (SKA), will revolutionise our understanding of the universe through their unprecedented sensitivity and resolution. However, standard methods in radio interferometry…

Instrumentation and Methods for Astrophysics · Physics 2017-02-23 Luke Pratley , Jason D. McEwen , Mayeul d'Avezac , Rafael E. Carrillo , Alexandru Onose , Yves Wiaux

The knowledge of the exact structure of the optical system PSF enables a high-quality image reconstruction in fluorescence microscopy. Accurate PSF models account for the vector nature of light and the phase and amplitude modifications.…

Accurate beam modeling is important in many radio astronomy applications. In this paper, we focus on beam modeling for 21-cm intensity mapping experiments using radio interferometers, though the techniques also apply to single dish…

Instrumentation and Methods for Astrophysics · Physics 2025-09-16 Michael J. Wilensky , Philip Bull , Nicolas Fagnoni

The growing interest in satellite imagery has triggered the need for efficient mechanisms to extract valuable information from these vast data sources, providing deeper insights. Even though deep learning has shown significant progress in…

Computer Vision and Pattern Recognition · Computer Science 2024-06-04 Wadii Boulila , Eman Alshanqiti , Ayyub Alzahem , Anis Koubaa , Nabil Mlaiki

Radio interferometric data are used to estimate the sky brightness distributions in radio frequencies. Here we focus on estimators of the large-scale structure and the power spectrum of the sky brightness distribution inferred from radio…

Instrumentation and Methods for Astrophysics · Physics 2019-04-17 Prasun Dutta , Meera Nandakumar

We have recently developed a new method for adjusting weights to minimize sidelobes in the spectral window. Here we show the results of applying this method to published two-site velocity observations of three stars (alpha Cen A, alpha Cen…

Solar and Stellar Astrophysics · Physics 2009-01-26 T. Arentoft , H. Kjeldsen , T. R. Bedding

In the near infrared where detectors are limited by read-out noise, most interferometers have been operated in wide band in order to benefit from larger photon rates. We analyze in this paper the biases caused by instrumental and turbulent…

Astrophysics · Physics 2009-11-10 G. Perrin , S. T. Ridgway

The calibration of modern radio interferometers is a significant challenge, specifically at low frequencies. In this perspective, we propose a novel iterative calibration algorithm, which employs the popular sparse representation framework,…

Instrumentation and Methods for Astrophysics · Physics 2016-06-06 Martin Brossard , Mohamed Nabil El Korso , Marius Pesavento , Rémy Boyer , Pascal Larzabal

Shrinkage estimators that possess the ability to produce sparse solutions have become increasingly important to the analysis of today's complex datasets. Examples include the LASSO, the Elastic-Net and their adaptive counterparts.…

Methodology · Statistics 2017-02-09 Hongmei Liu , J. Sunil Rao