English
Related papers

Related papers: Progressive Prediction of Turbulence Using Wave-Fr…

200 papers

Servo lag errors in adaptive optics lead to inaccurate compensation of wavefront distortions. An attempt has been made to predict future wavefronts using data mining on wavefronts of the immediate past to reduce these errors. Monte Carlo…

Instrumentation and Methods for Astrophysics · Physics 2009-11-08 Akondi Vyas , M B Roopashree , B Raghavendra Prasad

We present the details of predicting atmospheric turbulence by mining Zernike moment data obtained from simulations as well as experiments. Temporally correlated optical wave-fronts were simulated such that they followed Kolmogorov phase…

Instrumentation and Methods for Astrophysics · Physics 2011-09-14 Akondi Vyas , M. B. Roopashree , B. Raghavendra Prasad

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

There are different techniques to sense the wavefront phase-distortions due to atmospheric turbulence. Curvature sensors are practical in their sensitivity being adjustable to the prevailing atmospheric conditions. Even at the best sites,…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Aglae Kellerer , Mark Chun , Christ Ftaclas

We design an optical feedback network making use of machine learning techniques and demonstrate via simulations its ability to correct for the effects of turbulent propagation on optical modes. This artificial neural network scheme only…

Signal Processing · Electrical Eng. & Systems 2018-06-22 Sanjaya Lohani , Ryan T. Glasser

In tomographic adaptive-optics (AO) systems, errors due to tomographic wave-front reconstruction limit the performance and angular size of the scientific field of view (FoV), where AO correction is effective. We propose a multi time-step…

Instrumentation and Methods for Astrophysics · Physics 2016-04-12 Yoshito H. Ono , Masayuki Akiyama , Shin Oya , Olivier Lardiere , David R. Andersen , Carlos Correia , Kate Jackson , Colin Bradley

Dynamic wavefront aberrations negatively impact a wide range of optical applications including astronomy, optical free-space telecommunications and bio-imaging. Wavefront errors can be compensated by an adaptive optics system comprised of a…

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

We present a simple method of extracting a small number of reference optical turbulence and wind profiles from a large dataset for single conjugate and extreme adaptive optics simulations. These reference profiles can be used in slow…

Instrumentation and Methods for Astrophysics · Physics 2022-10-18 O. J. D. Farley

An analytical expression is given for the minimum of the time-delay induced wavefront error (also known as the servo-lag error) in Adaptive Optics systems under temporal prediction filtering. The analysis is based on the von K\'arm\'an…

Instrumentation and Methods for Astrophysics · Physics 2020-06-22 Niek Doelman

Increasing interest in astronomical applications of non-linear curvature wavefront sensors for turbulence detection and correction makes it important to understand how best to handle the data they produce, particularly at low light levels.…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 P. L. Aisher , J. Crass , C. Mackay

Channel turbulence is a formidable obstacle for free-space optical (FSO) communication. Anticipation of turbulence levels is highly important for mitigating disruptions but has not been demonstrated without dedicated, auxiliary hardware. We…

Systems and Control · Electrical Eng. & Systems 2025-03-26 Md Zobaer Islam , Ethan Abele , Fahim Ferdous Hossain , Arsalan Ahmad , Sabit Ekin , John F. O'Hara

Integration of multimodal information from various sources has been shown to boost the performance of machine learning models and thus has received increased attention in recent years. Often such models use deep modality-specific networks…

Machine Learning · Computer Science 2022-11-22 Shiv Shankar , Laure Thompson , Madalina Fiterau

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 ability to simulate atmospheric turbulence in the lab is a crucial part of testing and developing astronomical adaptive optics technology. We report on the development of a technique for creating phase plates, which involves the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 Rachel Rampy , Don Gavel , Daren Dillon , Sandrine Thomas

We use a theoretical frame-work to analytically assess temporal prediction error functions on von-Karman turbulence when a zonal representation of wave-fronts is assumed. Linear prediction models analysed include auto-regressive of order up…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 Kate Jackson , Carlos Correia , Olivier Lardiere , Dave Andersen , Colin Bradley

A convolutional encoder-decoder-based transformer model is proposed for autoregressively training on spatio-temporal data of turbulent flows. The prediction of future fluid flow fields is based on the previously predicted fluid flow field…

Fluid Dynamics · Physics 2023-03-31 Aakash Patil , Jonathan Viquerat , Elie Hachem

Data-driven turbulence modeling has been considered an effective method for improving the prediction accuracy of Reynolds-averaged Navier-Stokes equations. Related studies aimed to solve the discrepancy of traditional turbulence modeling by…

Fluid Dynamics · Physics 2020-10-19 Yuhui Yin , Pu Yang , Yufei Zhang , Haixin Chen , Song Fu

Optical turbulence, driven by fluctuations of the atmospheric refractive index, poses a significant challenge to ground-based optical systems, as it distorts the propagation of light. This degradation affects both astronomical observations…

Instrumentation and Methods for Astrophysics · Physics 2026-03-26 Mary Joe Medlej , Rahul Srinivasan , Simon Prunet , Aziz Ziad , Christophe Giordano

Data from experiments and direct simulations of turbulence have historically been used to calibrate simple engineering models such as those based on the Reynolds-averaged Navier--Stokes (RANS) equations. In the past few years, with the…

Fluid Dynamics · Physics 2019-01-30 Karthik Duraisamy , Gianluca Iaccarino , Heng Xiao
‹ Prev 1 2 3 10 Next ›