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Due to limited size and imperfect of the optical components in a spectrometer, aberration has inevitably been brought into two-dimensional multi-fiber spectrum image in LAMOST, which leads to obvious spacial variation of the point spread…

Instrumentation and Methods for Astrophysics · Physics 2020-10-28 Jiali Xu , Qian Yin , Ping Guo , Xin Zheng

We present a performance test of the Point Spread Function deconvolution algorithm applied to astronomical Integral Field Unit (IFU) Spectroscopy data for restoration of galaxy kinematics. We deconvolve the IFU data by applying the…

Astrophysics of Galaxies · Physics 2021-12-22 Haeun Chung , Changbom Park , Yong-Sun Park

CONTEXT: High-resolution spectroscopy across spatially resolved stellar surfaces aims at obtaining spectral-line profiles that are free from rotational broadening; the gradual changes of these profiles from disk center toward the stellar…

Solar and Stellar Astrophysics · Physics 2017-09-20 Dainis Dravins , Hans-Günter Ludwig , Erik Dahlén , Hiva Pazira

Aims. We study the 2D spectral line profile of HARPS (High Accuracy Radial Velocity Planet Searcher), measuring its variation with position across the detector and with changing line intensity. The characterization of the line profile and…

The spatial resolution of astronomical images is limited by atmospheric turbulence and diffraction in the telescope optics, resulting in blurred images. This makes it difficult to accurately measure the brightness of blended objects because…

Instrumentation and Methods for Astrophysics · Physics 2023-05-31 Kevin Michalewicz , Martin Millon , Frédéric Dux , Frédéric Courbin

(Abridged) In the first part of this thesis, a general methodology for applying image deconvolution to wide-field CCD imagery. Results show that wavelet-based deconvolution can increase limiting magnitude up to 0.6 mag and improve limiting…

Astrophysics · Physics 2007-05-23 O. Fors

The radial velocity (RV) method, also known as Doppler spectroscopy, is a powerful technique for exoplanet discovery and characterization. In recent years, progress has been made thanks to the improvements in the quality of spectra from new…

Earth and Planetary Astrophysics · Physics 2026-01-06 Joseph Salzer , Jessi Cisewski-Kehe , Eric B. Ford , Lily L. Zhao

Angular and spectral differential imaging is an observational technique of choice to investigate the immediate vicinity of stars. The relative angular motion and spectral scaling between on-axis and off-axis sources are exploited by…

Instrumentation and Methods for Astrophysics · Physics 2024-10-04 Olivier Flasseur , Loïc Denis , Éric Thiébaut , Maud Langlois

High-contrast imaging (HCI) is a technique designed to observe faint signals near bright sources, such as exoplanets and circumstellar disks. The primary challenge in revealing the faint circumstellar signal near a star is the presence of…

Earth and Planetary Astrophysics · Physics 2024-08-21 Sandrine Juillard , Valentin Christiaens , Olivier Absil , Sophia Stasevic , Julien Milli

Deep learning has shown great potential in accelerating diffusion tensor imaging (DTI). Nevertheless, existing methods tend to suffer from Rician noise and eddy current, leading to detail loss in reconstructing the DTI-derived parametric…

Image and Video Processing · Electrical Eng. & Systems 2024-08-21 Wenxin Fan , Jian Cheng , Cheng Li , Jing Yang , Ruoyou Wu , Juan Zou , Shanshan Wang

Detections of Earth-analog planets in radial velocity observations are limited by stellar astrophysical variability occurring on a variety of timescales. Current state-of-the-art methods to disentangle potential planet signals from…

Ashenhurst-Curtis decomposition (ACD) is a decomposition technique used, in particular, to map combinational logic into lookup tables (LUTs) structures when synthesizing hardware designs. However, available implementations of ACD suffer…

Logic in Computer Science · Computer Science 2024-06-11 Alessandro Tempia Calvino , Alan Mishchenko , Giovanni De Micheli , Robert Brayton

Due to the ever-expanding volume of observed spectroscopic data from surveys such as SDSS and LAMOST, it has become important to apply artificial intelligence (AI) techniques for analysing stellar spectra to solve spectral classification…

Solar and Stellar Astrophysics · Physics 2020-01-08 Kaushal Sharma , Ajit Kembhavi , Aniruddha Kembhavi , T. Sivarani , Sheelu Abraham , Kaustubh Vaghmare

Identifying new observational probes to constrain cosmological parameters has become an important goal in modern cosmology. In this work, we explore the potential of the cosmic star formation rate density (SFRD), compiled over the redshift…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-21 Miguel Moyses , Rafael C. Nunes

Video-based person re-identification has received increasing attention recently, as it plays an important role within surveillance video analysis. Video-based Re-ID is an expansion of earlier image-based re-identification methods by…

Computer Vision and Pattern Recognition · Computer Science 2020-08-18 Toby P. Breckon , Aishah Alsehaim

Redshift-space distortions (RSD), caused by the peculiar velocities of galaxies, are a key modelling challenge in galaxy clustering analyses, limiting the scales from which cosmological information can be reliably extracted. Unlike…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-31 Alexander Eggemeier , Nanoom Lee , Román Scoccimarro , Benjamin Camacho-Quevedo , Andrea Pezzotta , Martin Crocce , Ariel G. Sánchez

Our long-range goal is to improve current whole-heart CT calcium score by extracting quantitative features from individual calcifications. We performed deconvolution to improve small calcifications assessment which challenge conventional CT…

The Brighter-Fatter (hereafter BF) effect in CCD sensors causes increases in the image size of bright objects due to electrostatic repulsion of collected charges. Correcting this effect in the LSST camera is required in order to meet the…

Instrumentation and Methods for Astrophysics · Physics 2019-11-22 Craig Lage

Within the context of upcoming full-sky lensing surveys, the edge-preserving non- linear algorithm Aski is presented. Using the framework of Maximum A Posteriori inversion, it aims at recovering the full-sky convergence map from surveys…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 C. Pichon , E. Thiebaut , S. Prunet , K. Benabed , S. Colombi , T. Sousbie , R. Teyssier

Spectroscopic redshift surveys are key tools to trace the large-scale structure (LSS) of the Universe and test the $\Lambda$CDM model. However, using redshifts as distance proxies introduces distortions in the 3D galaxy distribution. If…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-09 Edoardo Maragliano , Punyakoti Ganeshaiah Veena , Giulia Degni , Enzo Franco Branchini