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Related papers: De-biasing interferometric visibilities in VLTI-AM…

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Stacking analysis is a means of detecting faint sources using a priori position information to estimate an aggregate signal from individually undetected objects. Confusion severely limits the effectiveness of stacking in deep surveys with…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Peter Kurczynski , Eric Gawiser

We discuss the present performance and the future perspectives of VLBI in the 3 mm to 0.85 mm observing bands (so called mm-VLBI). The availability of new telescopes and the recent technical development towards larger observing bandwidth…

Astrophysics · Physics 2008-12-23 T. P. Krichbaum , U. Bach , D. A. Graham , W. Alef , A. Roy , A. Witzel , J. A. Zensus , M. Bremer , S. Sanchez

Interferometric detection of mirror displacements is intrinsically limited by laser shot noise. In practice, however, it is often limited by thermal noise. Here we report on an experiment performed at the liquid helium temperature to…

Optics · Physics 2011-07-29 J. Laurent , A. Mosset , O. Arcizet , J. Chevrier , S. Huant , H. Sellier

The implementation of the simultaneous combination of several telescopes (from four to eight) available at Very Large Telescope Interferometer (VLTI) will allow the new generation interferometric instrumentation to achieve interferometric…

Astrophysics · Physics 2009-11-13 L. Corcione , D. Bonino , D. F. Busher , M. Gai , S. Ligori , D. Loreggia , G. Masssone , J. S. Young

This work proposes to reduce visibility data volume using a baseline-dependent lossy compression technique that preserves smearing at the edges of the field-of-view. We exploit the relation of the rank of a matrix and the fact that a…

Instrumentation and Methods for Astrophysics · Physics 2023-04-17 M Atemkeng , S Perkins , E Seck , S Makhathini , O Smirnov , L Bester , B Hugo

Very long baseline interferometry (VLBI) makes it possible to recover images of astronomical sources with extremely high angular resolution. Most recently, the Event Horizon Telescope (EHT) has extended VLBI to short millimeter wavelengths…

Instrumentation and Methods for Astrophysics · Physics 2018-02-05 Katherine L. Bouman , Michael D. Johnson , Adrian V. Dalca , Andrew A. Chael , Freek Roelofs , Sheperd S. Doeleman , William T. Freeman

The measurement of shape parameters of sources in astronomical images is usually performed by assuming that the underlying noise is uncorrelated. Spatial noise correlation is however present in practice due to various observational effects…

Astrophysics · Physics 2007-05-23 A. Refregier , S. T. Brown

We attempt to make a direct measurement of the weak lensing signal from the WMAP 7-year data. We apply the real-space implementation of the optimal quadratic estimator on the maps produced by the W-band Differencing Assemblies. We obtain a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 C. Sofia Carvalho , Ismael Tereno , Spyros Basilakos

The fairness of a deep neural network is strongly affected by dataset bias and spurious correlations, both of which are usually present in modern feature-rich and complex visual datasets. Due to the difficulty and variability of the task,…

Computer Vision and Pattern Recognition · Computer Science 2024-02-28 Rebecca S Stone , Nishant Ravikumar , Andrew J Bulpitt , David C Hogg

Foreground subtraction is the biggest challenge for future redshifted 21 cm observations to probe reionization. We use a short GMRT observation at 153 MHz to characterize the statistical properties of the background radiation across ~ one…

Astrophysics · Physics 2009-11-13 SK. Saiyad Ali , Somnath Bharadwaj , Jayaram N. Chengalur

Text-to-image (TTI) diffusion models have achieved remarkable visual quality, yet they have been repeatedly shown to exhibit social biases across sensitive attributes such as gender, race and age. To mitigate these biases, existing…

Machine Learning · Computer Science 2026-03-18 Manos Plitsis , Giorgos Bouritsas , Vassilis Katsouros , Yannis Panagakis

We present the program `Catalogue of proper motions in extragalactic jets from Active galactic Nuclei with Very large Array Studies' or CAgNVAS, with the objective of using archival and new VLA observations to measure proper motions of jet…

Instrumentation and Methods for Astrophysics · Physics 2023-12-21 Agniva Roychowdhury , Eileen T. Meyer

Fourier Transform Interferometry (FTI) is an appealing Hyperspectral (HS) imaging modality for many applications demanding high spectral resolution, e.g., in fluorescence microscopy. However, the effective resolution of FTI is limited by…

Information Theory · Computer Science 2019-01-31 A. Moshtaghpour , L. Jacques , V. Cambareri , P. Antoine , M. Roblin

Purpose: This study presents a variable resolution (VR) sampling and deep learning reconstruction approach for multi-spectral MRI near metal implants, aiming to reduce scan times while maintaining image quality. Background: The rising use…

Image and Video Processing · Electrical Eng. & Systems 2024-11-01 Azadeh Sharafi , Nikolai J. Mickevicius , Mehran Baboli , Andrew S. Nencka , Kevin M. Koch

Low fluence illumination sources can facilitate clinical transition of photoacoustic imaging because they are rugged, portable, affordable, and safe. However, these sources also decrease image quality due to their low fluence. Here, we…

Image and Video Processing · Electrical Eng. & Systems 2020-04-21 Ali Hariri , Kamran Alipour , Yash Mantri , Jurgen P. Schulze , Jesse V. Jokerst

Very long baseline interferometry (VLBI) provides the highest-resolution images in astronomy. The sharpest resolution is nominally achieved at the highest frequencies, but as the observing frequency increases so too does the atmospheric…

We present a multi-calibrator solution, i.e. MultiView, to achieve accurate astrometry on the level of the thermal noise at low VLBI frequencies dominated by ionospheric residuals. We demonstrate on L-band VLBA observations how MultiView…

Instrumentation and Methods for Astrophysics · Physics 2018-04-10 Gabor Orosz , Maria J. Rioja , Richard Dodson , Hiroshi Imai , Sandor Frey

Image reconstruction-based anomaly detection models are widely explored in industrial visual inspection. However, existing models usually suffer from the trade-off between normal reconstruction fidelity and abnormal reconstruction…

Computer Vision and Pattern Recognition · Computer Science 2025-03-17 Tongkun Liu , Bing Li , Xiao Du , Bingke Jiang , Leqi Geng , Feiyang Wang , Zhuo Zhao

In this paper, we consider random phase fluctuations imposed during wave propagation through a turbulent plasma (e.g. ionosphere) as a source of additional noise in interferometric visibilities. We derive expressions for visibility variance…

Instrumentation and Methods for Astrophysics · Physics 2015-12-02 H. K. Vedantham , L. V. E. Koopmans

Image reconstruction in very-long baseline interferometry operates under severely sparse aperture coverage with calibration challenges from both the participating instruments and propagation medium, which introduce the risk of biases and…

Instrumentation and Methods for Astrophysics · Physics 2026-01-14 Samuel Lai , Nithyanandan Thyagarajan , O. Ivy Wong , Foivos Diakogiannis
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