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We suggest an adaptive sampling rule for obtaining information from noisy signals using wavelet methods. The technique involves increasing the sampling rate when relatively high-frequency terms are incorporated into the wavelet estimator,…

Statistics Theory · Mathematics 2007-06-13 Peter Hall , Spiridon Penev

Blur in X-ray radiographs not only reduces the sharpness of image edges but also reduces the overall contrast. The effective blur in a radiograph is the combined effect of blur from multiple sources such as the detector panel, X-ray source…

Image and Video Processing · Electrical Eng. & Systems 2020-09-08 K. Aditya Mohan , Robert M. Panas , Jefferson A. Cuadra

Simultaneous estimation of range and angle of close emitters usually requires a multidimensional search. This paper offers an algorithm to improve the position of an element of any array designed on the basis of some certain or random…

Information Theory · Computer Science 2014-11-04 Mohammadreza Darabi

As new large-scale astronomical surveys greatly increase the number of objects targeted and discoveries made, the requirement for efficient follow-up observations is crucial. Adaptive optics imaging, which compensates for the image-blurring…

Optimal error estimation is key to achieve accurate photometry and astrometry. Stellar fluxes and positions in high angular resolution images are typically measured with PSF fitting routines, such as StarFinder. However, the formal…

Instrumentation and Methods for Astrophysics · Physics 2022-08-12 E. Gallego-Cano , R. Schödel , A. T. Gallego-Calvente , A. M. Ghez

We present an algorithm capable of detecting diffuse, dim sources of any size in an astronomical image. These sources often defeat traditional methods for source finding, which expand regions around points of high intensity. Extended…

Instrumentation and Methods for Astrophysics · Physics 2016-01-05 T. Butler-Yeoman , M. Frean , C. P. Hollitt , D. W. Hogg , M. Johnston-Hollitt

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

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

We consider the problem of analyzing the structure of spectroscopic cubes using unsupervised machine learning techniques. We propose representing the target's signal as a homogeneous set of volumes through an iterative algorithm that…

Instrumentation and Methods for Astrophysics · Physics 2018-06-15 Mauricio Araya , Marcelo Mendoza , Mauricio Solar , Diego Mardones , Amelia Bayo

The 21 cm radiation of neutral hydrogen provides crucial information for studying the early universe and its evolution. To advance this research, countries have made significant investments in constructing large low-frequency radio…

Instrumentation and Methods for Astrophysics · Physics 2025-08-04 Ming-wei Qin , Rui Tang , Ying-hui Zhou , Chang-jun Lan , Wen-hao Fu , Huan Wang , Bao-lin Hou , Zamri , Jin-song Ping , Wen-jun Yang , Liang Dong

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

We propose a new space-variant anisotropic regularisation term for variational image restoration, based on the statistical assumption that the gradients of the target image distribute locally according to a bivariate generalised Gaussian…

Numerical Analysis · Mathematics 2019-04-04 Luca Calatroni , Alessandro Lanza , Monica Pragliola , Fiorella Sgallari

A new method for improving the resolution of astronomical images is presented. It is based on the principle that sampled data cannot be fully deconvolved without violating the sampling theorem. Thus, the sampled image should not be…

Astrophysics · Physics 2009-10-30 P. Magain , F. Courbin , S. Sohy

The theory of semiparametric estimation offers an elegant way of computing the Cram\'er-Rao bound for a parameter of interest in the midst of infinitely many nuisance parameters. Here I apply the theory to the problem of moment estimation…

Image and Video Processing · Electrical Eng. & Systems 2019-10-09 Mankei Tsang

In recent years, deep learning has been successfully applied in various scientific domains. Following these promising results and performances, it has recently also started being evaluated in the domain of radio astronomy. In particular,…

Reliable adaptive beamforming is critical for large microphone arrays operating in highly dynamic acoustic environments. In scenarios characterized by fast-moving talkers and interferers, the available sample support for estimating the…

Systems and Control · Electrical Eng. & Systems 2026-05-07 Manan Mittal , Ryan M. Corey , John R. Buck , Andrew C. Singer

We propose an adaptive biasing algorithm aimed at enhancing the sampling of multimodal measures by Langevin dynamics. The underlying idea consists in generalizing the standard adaptive biasing force method commonly used in conjunction with…

Analysis of PDEs · Mathematics 2010-08-23 Chris Chipot , Tony Lelièvre

In this paper, we investigate diagonal estimation for large or implicit matrices, aiming to develop a novel and efficient stochastic algorithm that incorporates adaptive parameter selection. We explore the influence of different eigenvalue…

Machine Learning · Statistics 2024-10-16 Zongyuan Han , Wenhao Li , Shengxin Zhu

We describe a new concept to correct for scintillation noise on high-precision photometry in large and extremely large telescopes using telemetry data from adaptive optics (AO) systems. Most wide-field AO systems designed for the current…

Instrumentation and Methods for Astrophysics · Physics 2014-11-25 James Osborn

Radio astronomical observations have very poor signal to noise ratios, unlike in other disciplines. On the other hand, it is possible to observe the object of interest for long time intervals as well as using a wider bandwidth.…

Astrophysics · Physics 2008-09-02 Sarod Yatawatta