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In this letter we study the subwavelength imaging of sparse broadband sources inside a disordered medium by processing the data acquired by a single antenna. A mathematical model has been developed for solving such problem based on the idea…

Optics · Physics 2015-06-18 Lianlin Li , Fang Li , Tie Jun Cui

With the use of simulated supernova catalogs, we show that the statefinder parameters turn out to be poorly and biased estimated by standard cosmography. To this end, we compute their standard deviations and several bias statistics on…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-09 Alejandro Aviles , Jaime Klapp , Orlando Luongo

Variational regularization of ill-posed inverse problems is based on minimizing the sum of a data fidelity term and a regularization term. The balance between them is tuned using a positive regularization parameter, whose automatic choice…

Numerical Analysis · Mathematics 2025-11-12 Markus Juvonen , Bjørn Jensen , Ilmari Pohjola , Yiqiu Dong , Samuli Siltanen

In this technical communique, we propose a novel observer-based adaptive scheme to deal with the parameter estimation problem of biased sinusoidal signals. Different from the existing adaptive frequency estimation scheme, the proposed…

Dynamical Systems · Mathematics 2020-12-29 Shang Shi , Huifang Min , Shihong Ding

Observers are well known in control theory. Originally designed to estimate the hidden states of dynamical systems given some measurements, the observers scope has been recently extended to the estimation of some unknowns, for systems…

Optimization and Control · Mathematics 2014-01-21 Sharefa Asiri , Taous-Meriem Laleg-Kirati , Chadia Zayane-Aissa

We present a new imaging technique, swept-angle synthetic wavelength interferometry, for full-field micron-scale 3D sensing. As in conventional synthetic wavelength interferometry, our technique uses light consisting of two…

Computer Vision and Pattern Recognition · Computer Science 2023-03-31 Alankar Kotwal , Anat Levin , Ioannis Gkioulekas

In this paper we introduce a new observable to measure cosmic shear. We show that if we can measure with good accuracy both, the orientation of a galaxy and the polarisation direction of its radio emission, the angle between them is…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-14 Jérémie Francfort , Giulia Cusin , Ruth Durrer

Resampling techniques are being widely used at different stages of satellite image processing. The existing methodologies cannot perfectly recover features from a completely under sampled image and hence an intelligent adaptive resampling…

Computer Vision and Pattern Recognition · Computer Science 2014-05-26 S. K. Katiyar , P. V. Arun

Adaptive optics enables the deployment of interferometer-based spectroscopy without the need for moving parts necessary for scanning the interferometer arms. Here, we employ a Michelson Interferometer in conjunction with a Spatial Light…

Optics · Physics 2025-12-05 Jesneil Lauren Lewis , Ayan Banerjee

Sparse aperture masking (SAM) interferometry combined with Adaptive Optics (AO) is a technique that is uniquely suited to investigate structures near the diffraction limit of large telescopes. The strengths of the technique are a robust…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 J. Sanchez-Bermudez , R. Schoedel , A. Alberdi , J. U. Pott

It is developed a very complex system (hardware/software) to detect luminosity variations connected with the discovery of new planets outside the Solar System. Traditional imaging approaches are very demanding in terms of computing time;…

Computer Vision and Pattern Recognition · Computer Science 2007-05-23 G. Iovane

The effects of the antenna far-field power pattern limits the imaging performance of modern wide-bandwidth, high-sensitivity interferometric radio telescopes. Given a model for the aperture illumination pattern (AIP) of the antenna,…

Instrumentation and Methods for Astrophysics · Physics 2017-12-11 Preshanth Jagannathan , S. Bhatnagar , W. Brisken , A. R. Taylor

The recent proposal of a new alignment solution for X-ray tomography, Virtual alignment method (VAM) allowed a more accurate method to remove the possible errors that limit the resolution and clarity of the reconstructed image. In the field…

Image and Video Processing · Electrical Eng. & Systems 2020-10-28 Kyungtaek Jun , Seokhwan Yoon , Jae-Hong Lim , SeungJoon Noh

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

Data from radio interferometers provide a substantial challenge for statisticians. It is incomplete, noise-dominated and originates from a non-trivial measurement process. The signal is not only corrupted by imperfect measurement devices…

Instrumentation and Methods for Astrophysics · Physics 2020-11-11 Philipp Arras , Jakob Knollmüller , Henrik Junklewitz , Torsten A. Enßlin

Many adaptive optics systems operate by measuring the distortion of the wavefront in one wavelength range and performing the scientific observations in a second, different wavelength range. One common technique is to measure wavefront…

Astrophysics · Physics 2009-11-07 Henry G. Roe

Radio maps find numerous applications in wireless communications and mobile robotics tasks, including resource allocation, interference coordination, and mission planning. Although numerous techniques have been proposed to construct radio…

Signal Processing · Electrical Eng. & Systems 2022-01-14 Raju Shrestha , Daniel Romero , Sundeep Prabhakar Chepuri

The techniques of laser cooling combined with atom interferometry make possible the realization of very sensitive and accurate inertial sensors like gyroscopes or accelerometers. Besides earth-based developments, the use of these techniques…

Atomic Physics · Physics 2008-08-29 Arnaud Landragin , Franck Pereira Dos Santos

We propose a novel sensing approach for the beam alignment problem in millimeter wave systems using a single Radio Frequency (RF) chain. Conventionally, beam alignment using a single phased array involves comparing beamformer output power…

Signal Processing · Electrical Eng. & Systems 2024-04-12 Rohan R. Pote , Bhaskar D. Rao

We designed and built a new astronomical photo-polarimeter that can measure linear polarization simultaneously in three spectral bands. It has a Calcite beamdisplacement prism as the analyzer. The ordinary and extra-ordinary emerging beams…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 G. Srinivasulu , A. V. Raveendran , S. Muneer , M. V. Mekkaden , N. Jayavel , M. R. Somashekar , K. Sagayanathan , S. Ramamoorthy , M. J. Rosario , K. Jayakumar