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We probe turbulence structure from centimetric to metric scales by simultaneous imagery at mid-infrared and visible wavelengths at the VLT telescope and show that it departs significantly from the commonly used Kolmogorov model. The data…

Astrophysics · Physics 2009-06-23 A. Tokovinin , M. Sarazin , A. Smette

Atmospheric turbulence has a degrading effect on the image quality of long-range observation systems. As a result of various elements such as temperature, wind velocity, humidity, etc., turbulence is characterized by random fluctuations in…

Computer Vision and Pattern Recognition · Computer Science 2022-04-20 Engin Uzun , Ahmet Anil Dursun , Erdem Akagunduz

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

While Fourier ptychography (FP) offers super-resolution for macroscopic imaging, its real-world application is severely hampered by atmospheric turbulence, a challenge largely unaddressed in existing macroscopic FP research operating under…

For extremely large telescopes, adaptive optics will be required to correct the Earth's turbulent atmosphere. The performance of tomographic adaptive optics is strongly dependent on the vertical distribution (profile) of this turbulence. An…

Instrumentation and Methods for Astrophysics · Physics 2019-06-26 O. J. D. Farley , J. Osborn , T. Morris , T. Fusco , B. Neichel , C. Correia , R. W. Wilson

Atmospheric turbulence poses a significant challenge to the performance of object detection models. Turbulence causes distortions, blurring, and noise in images by bending and scattering light rays due to variations in the refractive index…

Computer Vision and Pattern Recognition · Computer Science 2024-05-13 Engin Uzun , Erdem Akagunduz

The search for Earth-like exoplanets requires high-contrast and high-angular resolution instruments, which designs can be very complex: they need an adaptive optics system to compensate for the effect of the atmospheric turbulence on image…

Instrumentation and Methods for Astrophysics · Physics 2020-12-16 Lucie Leboulleux , Raphaël Galicher , Eric Gendron , Pierre Baudoz , Gérard Rousset

Atmospheric Turbulence (AT) correction is a challenging restoration task as it consists of two distortions: geometric distortion and spatially variant blur. Diffusion models have shown impressive accomplishments in photo-realistic image…

Computer Vision and Pattern Recognition · Computer Science 2023-07-28 Xijun Wang , Santiago López-Tapia , Aggelos K. Katsaggelos

We study analytically and numerically the corrections to scaling in turbulence which arise due to the finite ratio of the outer scale $L$ of turbulence to the viscous scale $\eta$, i.e., they are due to finite size effects as anisotropic…

chao-dyn · Physics 2009-10-22 Siegfried Grossmann , Detlef Lohse , Victor L'vov , Itamar Procaccia

The performance of tomographic adaptive optics systems is intrinsically linked to the vertical profile of optical turbulence. Firstly, a sufficient number of discrete turbulent layers must be reconstructed to model the true continuous…

Instrumentation and Methods for Astrophysics · Physics 2020-04-08 O. J. D. Farley , J. Osborn , T. Morris , T. Fusco , B. Neichel , C. Correia , R. W. Wilson

Monitoring turbulence parameters is crucial in high-angular resolution astronomy for various purposes, such as optimising adaptive optics systems or fringe trackers. The former are present at most modern observatories and will remain…

Instrumentation and Methods for Astrophysics · Physics 2023-10-25 Nuno Morujão , Carlos Correia , Paulo Andrade , Julien Woillez , Paulo Garcia

Adaptive optics (AO) is a technology in modern ground-based optical telescopes to compensate the wavefront distortions caused by atmospheric turbulence. One method that allows to retrieve information about the atmosphere from telescope data…

Instrumentation and Methods for Astrophysics · Physics 2018-04-04 Tapio Helin , Stefan Kindermann , Jonatan Lehtonen , Ronny Ramlau

We discuss several improvements in the detection of atmospheric turbulence using SLOpe Detection And Ranging (SLODAR). Frequently, SLODAR observations have shown strong ground-layer turbulence, which is beneficial to adaptive optics. We…

Astrophysics · Physics 2009-11-13 Michael Goodwin , Charles Jenkins , Andrew Lambert

The estimation of atmospheric turbulence parameters is of relevance for: a) site evaluation & characterisation; b) prediction of the point spread function; c) live assessment of error budgets and optimisation of adaptive optics performance;…

Instrumentation and Methods for Astrophysics · Physics 2018-12-19 Paulo P. Andrade , Paulo J. V. Garcia , Carlos M. Correia , Johann Kolb , Maria Inês Carvalho

Phase referencing is a standard calibration procedure in radio interferometry. It allows to detect weak sources by using quasi-simultaneous observations of closeby sources acting as calibrators. Therefore, it is assumed that, for each…

Instrumentation and Methods for Astrophysics · Physics 2011-01-25 I. Marti-Vidal , J. C. Guirado , S. Jimenez-Monferrer , J. M. Marcaide

Atmospheric turbulence can significantly degrade the quality of images acquired by long-range imaging systems by causing spatially and temporally random fluctuations in the index of refraction of the atmosphere. Variations in the refractive…

Image and Video Processing · Electrical Eng. & Systems 2022-07-08 Rajeev Yasarla , Vishal M. Patel

Atmospheric turbulence, a common phenomenon in daily life, is primarily caused by the uneven heating of the Earth's surface. This phenomenon results in distorted and blurred acquired images or videos and can significantly impact downstream…

Computer Vision and Pattern Recognition · Computer Science 2024-02-13 Xijun Wang , Santiago López-Tapia , Aggelos K. Katsaggelos

Correlated imaging through atmospheric turbulence is studied, and the analytical expressions describing turbulence effects on image resolution are derived. Compared with direct imaging, correlated imaging can reduce the influence of…

Optics · Physics 2015-05-19 Pengli Zhang , Wenlin Gong , Xia Shen , Shensheng Han

The efficiency of the management of top-class ground-based astronomical facilities supported by Adaptive Optics (AO) relies on our ability to forecast the optical turbulence (OT) and a set of relevant atmospheric parameters. Indeed, in…

Instrumentation and Methods for Astrophysics · Physics 2020-06-14 E. Masciadri , G. Martelloni , A. Turchi

The strength and vertical distribution of atmospheric turbulence is a key factor determining the performance of optical and infrared telescopes, with and without adaptive optics. Yet, this remains challenging to measure. We describe a new…

Instrumentation and Methods for Astrophysics · Physics 2019-10-11 Paul Hickson , Bin Ma , Zhaohui Shang , Suijian Xue
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