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A technique is described for the detection and measurement of close binary systems whose images are unresolved. The method is based on analysis of the moment of inertia tensor of the image, from which the product of the binary flux ratio…

Astrophysics · Physics 2009-10-30 Paul Hickson

The Straightness is a measure designed to characterize a pair of vertices in a spatial graph. It is defined as the ratio of the Euclidean distance to the graph distance between these vertices. It is often used as an average, for instance to…

Discrete Mathematics · Computer Science 2023-05-12 Vincent Labatut

The Chinese Space Station Telescope (CSST) spectroscopic survey aims to deliver high-quality low-resolution ($R > 200$) slitless spectra for hundreds of millions of targets down to a limiting magnitude of about 21 mag, distributed within a…

Instrumentation and Methods for Astrophysics · Physics 2021-05-05 Haibo Yuan , Dingshan Deng , Yang Sun

Longslit spectroscopy is entering an era of increased spatial and spectral resolution and increased sample size. Improved instruments reveal complex velocity structure that cannot be described with a one-dimensional rotation curve, yet…

A major aspect in power line distribution networks is the constant monitoring of the network properties. With the advent of the smart grid concept, distributed monitoring has started complementing the information of the central stations. In…

Physics and Society · Physics 2019-02-07 Federico Passerini , Andrea M. Tonello

The problem of imaging extended targets (sources or scatterers) is formulated in the framework of compressed sensing with emphasis on subwavelength resolution. The proposed formulation of the problems of inverse source/scattering is…

Optics · Physics 2009-09-15 Albert C. Fannjiang

Ellipse and ellipsoid fitting has been extensively researched and widely applied. Although traditional fitting methods provide accurate estimation of ellipse parameters in the low-noise case, their performance is compromised when the noise…

Methodology · Statistics 2009-12-10 Jieqi Yu , Sanjeev R. Kulkarni , H. Vincent Poor

Spectroscopically measuring low levels of non-equilibrium phenomena (e.g. emission in the presence of a large thermal background) can be problematic due to an unfavorable signal-to-noise ratio. An approach is presented to use time-series…

Geophysics · Physics 2015-04-08 John Scoville

Optical stellar interferometers have demonstrated milli-arcsecond resolution with few apertures spaced hundreds of meters apart. To obtain rich direct images, many apertures will be needed, for a better sampling of the incoming wavefront.…

Instrumentation and Methods for Astrophysics · Physics 2014-09-17 Arun Surya , Swapan K. Saha , Antoine Labeyrie

A variety of on-orbit imaging and spectroscopic observations are used to characterize the Charge Transfer Efficiency (CTE) of the Charge-Coupled Device (CCD) of the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space…

Astrophysics · Physics 2009-11-11 Paul Goudfrooij , Ralph C. Bohlin , Jesus Maiz-Apellaniz , Randy A. Kimble

We describe a self calibrating optical technique that allows to perform absolute measurements of scattering cross sections for the light scattered at extremely small angles. Very good performances are obtained by using a very simple optical…

Optics · Physics 2009-11-10 Doriano Brogioli , Alberto Vailati , Marzio Giglio

We present a method to measure the spectral density of in-band optical transmission impairments without coherent electrical reception and digital signal processing at the receiver. We determine the method's accuracy by numerical simulations…

Signal Processing · Electrical Eng. & Systems 2021-07-12 Sylvain Almonacil , Matteo Lonardi , Philippe Jenneve , Nicolas Dubreuil

This paper presents a fast algorithm for obtaining high-accuracy subpixel translation of low PSNR images. Instead of locating the maximum point on the upsampled images or fitting the peak of correlation surface, the proposed algorithm is…

Computer Vision and Pattern Recognition · Computer Science 2018-04-03 Song Feng , Linhua Deng , Guofeng Shu , Feng Wang , Hui Deng , Kaifan Ji

This paper presents a new Bayesian spectral unmixing algorithm to analyse remote scenes sensed via sparse multispectral Lidar measurements. To a first approximation, in the presence of a target, each Lidar waveform consists of a main peak,…

The preparation of a space-mission that carries out any kind of imaging to detect high-precision low-amplitude variability of its targets requires a robust model for the expected performance of its instruments. This model cannot be derived…

Instrumentation and Methods for Astrophysics · Physics 2016-10-27 P. Marcos-Arenal , W. Zima , J. De Ridder , R. Huygen , C. Aerts

Using photoemission intensities and a detection system employed by many groups in the electron spectroscopy community as an example, we have quantitatively characterized and corrected detector non-linearity effects over the full dynamic…

Instrumentation and Detectors · Physics 2007-05-23 N. Mannella , S. Marchesini , A. W. Kay , A. Nambu , T. Gresch , S. -H. Yang , B. S. Mun , J. M. Bussat , A. Rosenhahn , C. S. Fadley

Measuring neutron star radii with spectroscopic and timing techniques relies on the combination of multiple observables to break the degeneracies between the mass and radius introduced by general relativistic effects. Here, we explore a…

High Energy Astrophysical Phenomena · Physics 2015-10-21 Feryal Ozel , Dimitrios Psaltis

The noise of a device under test (DUT) is measured simultaneously with two instruments, each of which contributes its own background. The average cross power spectral density converges to the DUT power spectral density. This method enables…

Instrumentation and Detectors · Physics 2010-03-02 Enrico Rubiola , Francois Vernotte

Visbal & Loeb (2010) have shown that it is possible to measure the clustering of galaxies by cross correlating the cumulative emission from two different spectral lines which originate at the same redshift. Through this cross correlation,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Eli Visbal , Hy Trac , Abraham Loeb

Motivated by the recognition that variation in the optical transmission of the atmosphere is probably the main limitation to the precision of ground-based CCD measurements of celestial fluxes, we review the physical processes that attenuate…

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