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The main objective of the present project is to explore the viability of an adaptive optics control system based exclusively on Field Programmable Gate Arrays (FPGAs), making strong use of their parallel processing capability. In an…

Instrumentation and Methods for Astrophysics · Physics 2018-07-03 Avinash Surendran , Mahesh P. Burse , A. N. Ramaprakash , Padmakar Parihar

Recently, linear computed tomography (LCT) systems have actively attracted attention. To weaken projection truncation and image the region of interest (ROI) for LCT, the backprojection filtration (BPF) algorithm is an effective solution.…

Computer Vision and Pattern Recognition · Computer Science 2023-09-26 Zhisheng Wang , Zihan Deng , Fenglin Liu , Yixing Huang , Haijun Yu , Junning Cui

Here we present a laboratory analysis of the use of a 19-core photonic lantern (PL) in combination with neural network (NN) algorithms as an efficient focal plane wavefront sensor (FP-WFS) for adaptive optics (AO), measuring wavefront…

Optics · Physics 2023-11-06 Jin Wei , Barnaby Norris , Christopher Betters , Sergio Leon-Saval

The orbital angular momentum (OAM) of photons is a promising degree of freedom for high-dimensional quantum key distribution (QKD). However, effectively mitigating the adverse effects of atmospheric turbulence is a persistent challenge in…

Signal Processing · Electrical Eng. & Systems 2020-06-24 Jiapeng Zhao , Yiyu Zhou , Boris Braverman , Cong Liu , Kai Pang , Nicholas K. Steinhoff , Glenn A. Tyler , Alan E. Willner , Robert W. Boyd

Observational tests of ground layer wavefront recovery have been made in open loop using a constellation of four natural guide stars at the 1.55 m Kuiper telescope in Arizona. Such tests explore the effectiveness of wide-field seeing…

Astrophysics · Physics 2011-02-11 Christoph Baranec , Michael Lloyd-Hart , N. Mark Milton

We performed a series of three-dimensional numerical simulations of supersonic homogeneous Euler turbulence with adaptive mesh refinement (AMR) and effective grid resolution up to 1024^3 zones. Our experiments describe non-magnetized driven…

Astrophysics · Physics 2016-08-30 Alexei G. Kritsuk , Michael L. Norman , Paolo Padoan

Orthogonal time frequency space (OTFS) modulation has recently emerged as a potential 6G candidate waveform which provides improved performance in high-mobility scenarios. In this paper we investigate the combination of OTFS with…

Signal Processing · Electrical Eng. & Systems 2023-04-27 Stephen McWade , Arman Farhang , Mark F. Flanagan

Disturbances such as atmospheric turbulence and aero-optic effects lead to wavefront aberrations, which degrade performance in imaging and laser propagation applications. Adaptive optics (AO) provide a method to mitigate these effects by…

Signal Processing · Electrical Eng. & Systems 2024-10-17 Jeffrey Utley , Gregery Buzzard , Charles Bouman , Matthew Kemnetz

Long-range imaging inevitably suffers from atmospheric turbulence with severe geometric distortions due to random refraction of light. The further the distance, the more severe the disturbance. Despite existing research has achieved great…

Computer Vision and Pattern Recognition · Computer Science 2024-07-18 Shengqi Xu , Run Sun , Yi Chang , Shuning Cao , Xueyao Xiao , Luxin Yan

Channel estimation at millimeter wave (mmWave) is challenging when large antenna arrays are used. Prior work has leveraged the sparse nature of mmWave channels via compressed sensing based algorithms for channel estimation. Most of these…

Information Theory · Computer Science 2018-06-19 Nitin Jonathan Myers , Robert W. Heath

In time series analysis, when fitting an autoregressive model, one must solve a Toeplitz ordinary least squares problem numerous times to find an appropriate model, which can severely affect computational times with large data sets. Two…

Machine Learning · Statistics 2021-12-28 Ali Eshragh , Oliver Di Pietro , Michael A. Saunders

We present two reduced-rank channel estimators for large-scale multiple-input, multiple-output (MIMO) systems and analyze their mean square error (MSE) performance. Taking advantage of the channel's transform domain sparseness, the…

Information Theory · Computer Science 2016-09-09 Ko-Feng Chen , Yen-Cheng Liu , Yu T. Su

In this paper, we study low-complexity algorithms for beam and channel tracking for millimeter-wave (mmWave) communications. In particular, the least mean squares (LMS) and bidirectional LMS (BiLMS) algorithms are derived for a mobile…

Information Theory · Computer Science 2018-12-21 Yavuz Yapici , Ismail Guvenc

Closed-loop adaptive optics systems which use minimum mean square error wavefront reconstruction require the computation of pseudo open loop wavefront slopes. These techniques incorporate a knowledge of atmospheric statistics which must…

Instrumentation and Methods for Astrophysics · Physics 2019-04-10 Alastair Basden , David Jenkins , Tim Morris , James Osborn , Matthew Townson

Realizing high-throughput aberration-corrected Scanning Transmission Electron Microscopy (STEM) exploration of atomic structures requires rapid tuning of multipole probe correctors while compensating for the inevitable drift of the optical…

Machine Learning · Computer Science 2026-01-28 Utkarsh Pratiush , Austin Houston , Richard Liu , Gerd Duscher , Sergei Kalinin

The translation of imaging Mueller polarimetry to clinical practice is often hindered by large footprint and relatively slow acquisition speed of the existing instruments. Using polarization-sensitive camera as a detector may reduce…

Machine learning (ML) starts to be widely used to enhance the performance of multi-user multiple-input multiple-output (MU-MIMO) receivers. However, it is still unclear if such methods are truly competitive with respect to conventional…

Information Theory · Computer Science 2021-07-01 Mathieu Goutay , Fayçal Ait Aoudia , Jakob Hoydis , Jean-Marie Gorce

Magnetic resonance (MR)-$T_2^*$ mapping is widely used to study hemorrhage, calcification and iron deposition in various clinical applications, it provides a direct and precise mapping of desired contrast in the tissue. However, the long…

Image and Video Processing · Electrical Eng. & Systems 2020-08-06 Shuai Huang , James J. Lah , Jason W. Allen , Deqiang Qiu

The Adaptive Optics Facility (AOF) project envisages transforming one of the VLT units into an adaptive telescope and providing its ESO (European Southern Observatory) second generation instruments with turbulence corrected wavefronts. For…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 A. Garcia-Rissmann , A. Guesalaga , J. Kolb , M. Le Louarn , P. -Y. Madec , B. Neichel

Latency in the control loop of adaptive optics (AO) systems can severely limit performance. Under the frozen flow hypothesis linear predictive control techniques can overcome this, however identification and tracking of relevant turbulent…

Instrumentation and Methods for Astrophysics · Physics 2020-06-10 Xuewen Liu , Tim Morris , Chris Saunter , Francisco Javier de Cos Juez , Carlos González-Gutiérrez , Lisa Bardou