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We develop a novel algorithm for sparse Stokes parameters imaging in radio interferometry under the polarization constraint. The latter is a physical non-linear relation between the Stokes parameters, imposing that the polarization…

Instrumentation and Methods for Astrophysics · Physics 2018-07-18 Jasleen Birdi , Audrey Repetti , Yves Wiaux

Upcoming radio interferometers are aiming to image the sky at new levels of resolution and sensitivity, with wide-band image cubes reaching close to the Petabyte scale for SKA. Modern proximal optimization algorithms have shown a potential…

Instrumentation and Methods for Astrophysics · Physics 2023-08-22 Pierre-Antoine Thouvenin , Abdullah Abdulaziz , Arwa Dabbech , Audrey Repetti , Yves Wiaux

Context: Radio interferometers measure frequency components of the sky brightness, modulated by the gains of the individual radio antennas. Due to atmospheric turbulence and variations in the operational conditions of the antennas these…

Instrumentation and Methods for Astrophysics · Physics 2023-10-25 Jakob Roth , Philipp Arras , Martin Reinecke , Richard A. Perley , Rüdiger Westermann , Torsten A. Enßlin

The standard imaging algorithm for interferometric radio data, CLEAN, is optimal for point source observations, but suboptimal for diffuse emission. Recently, RESOLVE, a new Bayesian algorithm has been developed, which is ideal for extended…

Instrumentation and Methods for Astrophysics · Physics 2017-02-28 Maksim Greiner , Valentina Vacca , Henrik Junklewitz , Torsten A. Enßlin

We present the first direct imaging of what may be the thick torus in the active galactic nucleus (AGN) of the archetype powerful radio galaxy Cygnus A, using the Jansky Very Large Array (VLA) at 18 GHz to 48 GHz, with a resolution down to…

High Energy Astrophysical Phenomena · Physics 2019-07-17 C. L. Carilli , R. A. Perley , V. Dhawan , D. A. Perley

With excellent angular resolution, good energy resolution and broad energy band, the Chandra ACIS is the best instrument for studying the X-ray halos around some galactic X-ray point sources caused by the dust scattering of X-rays in the…

Astrophysics · Physics 2007-05-23 Y. Yao , S. Nan Zhang , X. L. Zhang , Y. X. Feng

Hyperspectral remote sensing images (HSIs) are characterized by having a low spatial resolution and a high spectral resolution, whereas multispectral images (MSIs) are characterized by low spectral and high spatial resolutions. These…

Computer Vision and Pattern Recognition · Computer Science 2014-06-11 Miguel Simões , José Bioucas-Dias , Luis B. Almeida , Jocelyn Chanussot

Next generation radio interferometric telescopes are entering an era of big data with extremely large data sets. While these telescopes can observe the sky in higher sensitivity and resolution than before, computational challenges in image…

Instrumentation and Methods for Astrophysics · Physics 2019-12-17 Luke Pratley , Jason D. McEwen , Mayeul d'Avezac , Xiaohao Cai , David Perez-Suarez , Ilektra Christidi , Roland Guichard

In this paper, we propose a novel algorithm for analysis-based sparsity reconstruction. It can solve the generalized problem by structured sparsity regularization with an orthogonal basis and total variation regularization. The proposed…

Computer Vision and Pattern Recognition · Computer Science 2015-04-29 Chen Chen , Junzhou Huang , Lei He , Hongsheng Li

Supervised deep learning approaches can artificially increase the resolution of microscopy images by learning a mapping between two image resolutions or modalities. However, such methods often require a large set of hard-to-get…

Image and Video Processing · Electrical Eng. & Systems 2024-11-20 Marzieh Gheisari , Auguste Genovesio

High-resolution Very-Long-Baseline Interferometry observations of relativistic jets are essential to constrain fundamental parameters of jet formation models. At a distance of 249 Mpc, Cygnus A is a unique target for such studies, being the…

High Energy Astrophysical Phenomena · Physics 2015-12-16 B. Boccardi , T. P. Krichbaum , U. Bach , F. Mertens , E. Ros , W. Alef , J. A. Zensus

Next generation radio telescopes, like the Square Kilometre Array, will acquire an unprecedented amount of data for radio astronomy. The development of fast, parallelisable or distributed algorithms for handling such large-scale data sets…

Instrumentation and Methods for Astrophysics · Physics 2016-10-28 Alexandru Onose , Rafael E. Carrillo , Jason D. McEwen , Yves Wiaux

Information about microscopic objects with features smaller than the diffraction limit is almost entirely lost in a far-field diffraction image but could be partly recovered with data completition techniques. Any such approach critically…

Optics · Physics 2020-11-17 Maria Bancerek , Krzysztof M. Czajkowski , Rafal Kotynski

We report on the assessment of the imaging performance of CITIUS -- a high-speed X-ray detector developed for the large-scale synchrotron radiation facility SPring-8-II -- for heavy charged particles and neutrons. To characterize the…

Instrumentation and Detectors · Physics 2026-05-25 Yoshio Kamiya , Haruki Nishino , Takaki Hatsui

The spatial-frequency coverage of a radio interferometer is increased by combining samples acquired at different times and observing frequencies. However, astrophysical sources often contain complicated spatial structure that varies within…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 U. Rau

A linear regression algorithm is applied to a digital-supermode distributed Bragg reflector laser to optimise wavelength switching times. The algorithm uses the output of a digital coherent receiver as feedback to update the pre-emphasis…

Signal Processing · Electrical Eng. & Systems 2020-04-22 Thomas Gerard , Hubert Dzieciol , Joshua Benjamin , Kari Clark , Hugh Williams , Benn Thomsen , Domaniç Lavery , Polina Bayvel

We present a supervised hyperspectral image segmentation algorithm based on a convex formulation of a marginal maximum a posteriori segmentation with hidden fields and structure tensor regularization: Segmentation via the Constraint Split…

Computer Vision and Pattern Recognition · Computer Science 2015-04-28 Filipe Condessa , Jose Bioucas-Dias , Jelena Kovacevic

In this paper, we consider the problem of super-resolution recons-truction. This is a hot topic because super-resolution reconstruction has a wide range of applications in the medical field, remote sensing monitoring, and criminal…

Image and Video Processing · Electrical Eng. & Systems 2019-07-25 Qi Zhang , Huafeng Wang , Sichen Yang

Radio interferometry allows astronomers to probe small spatial scales that are often inaccessible with single-dish instruments. However, recovering the radio sky from an interferometer is an ill-posed deconvolution problem that astronomers…

Instrumentation and Methods for Astrophysics · Physics 2022-05-25 Liam Connor , Katherine L. Bouman , Vikram Ravi , Gregg Hallinan

We report on the continuum and polarization observations of the Cygnus Loop supernova remnant (SNR) conducted by the Five-hundred-meter Aperture Spherical radio Telescope (FAST). FAST observations provide high angular resolution and high…

Astrophysics of Galaxies · Physics 2021-08-24 Xiaohui Sun , Meiniang Meng , Xuyang Gao , Wolfgang Reich , Peng Jiang , Di Li , Huirong Yan , Xianghua Li