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This paper introduces a new algorithm to improve the accuracy of numerical phase-averaging in oscillatory, multiscale, differential equations. Phase-averaging is a timestepping method which averages a mapped variable to remove highly…

Numerical Analysis · Mathematics 2024-11-07 Timothy C. Andrews , Beth A. Wingate

Fast spin-echo (FSE) pulse sequences for Magnetic Resonance Imaging (MRI) offer important imaging contrast in clinically feasible scan times. T2-shuffling is widely used to resolve temporal signal dynamics in FSE acquisitions by exploiting…

Image and Video Processing · Electrical Eng. & Systems 2023-03-07 Molin Zhang , Junshen Xu , Yamin Arefeen , Elfar Adalsteinsson

This letter investigates the uplink of a multi-user millimeter wave (mmWave) system, where the base station (BS) is equipped with a massive multiple-input multiple-output (MIMO) array and resolution-adaptive analog-to-digital converters…

Signal Processing · Electrical Eng. & Systems 2020-05-19 Hualian Sheng , Xihan Chen , Xiongfei Zhai , An Liu , Min-Jian Zhao

We address the problem of fast time-varying channel estimation in millimeter-wave (mmWave) MIMO systems with imperfect channel state information (CSI) and facilitate efficient channel reconstruction. Specifically, leveraging the low-rank…

Signal Processing · Electrical Eng. & Systems 2025-11-11 Tianyu Jiang , Yan Yang , Hongjin Liu , Runyu Han , Bo Ai , Mohsen Guizani

Accurate atmospheric profiles from remote sensing instruments such as Doppler Lidar, Radar, and radiometers are frequently corrupted by low-SNR (Signal to Noise Ratio) gates, range folding, and spurious discontinuities. Traditional gap…

Machine Learning · Computer Science 2026-01-15 Anurup Naskar , Nathanael Zhixin Wong , Sara Shamekh

The TP3-WFS (Two Pupil Plane Positions Wavefront Sensor) is, to the best of the authors' knowledge, the first physical implementation of the geometrical wavefront reconstruction algorithm that has been tested in a telescope as part of an…

Multi-photon microscopy is a powerful technique for deep-tissue imaging, providing high spatial resolution at increased penetration depth. Nevertheless, imaging remains largely restricted to superficial tissue layers well below 1 mm.…

Over the past fifty years, wavefront sensing technology has continuously evolved from basic techniques to high-precision systems, serving as a core methodology in adaptive optics (AO). Beyond traditional wavefront retrieval methods based on…

Optics · Physics 2025-05-13 Rundong Fan , Zichao Wang , Pei Li , Lei Huang

Synthetic aperture radar tomography (TomoSAR) enables 3-D imaging by exploiting multibaseline acquisitions and has become an important tool for urban mapping. To achieve super-resolution inversion, sparse reconstruction methods based on…

Signal Processing · Electrical Eng. & Systems 2026-04-22 Kun Qian , Zhuge Xia , Qian Ma , Qi Zhang , Weijian Liu , Xiufeng He

We build on a long-standing tradition in astronomical adaptive optics (AO) of specifying performance metrics and error budgets using linear systems modeling in the spatial-frequency domain. Our goal is to provide a comprehensive tool for…

Instrumentation and Methods for Astrophysics · Physics 2017-10-11 Carlos M. Correia , Charlotte Z. Bond , Jean-François Sauvage , Thierry Fusco , Rodolphe Conan , Peter Wizinowich

The Multi-conjugate Adaptive Optics RelaY (MAORY) is one of the key Adaptive Optics (AO) systems on the European Southern Observatory's Extremely Large Telescope. MAORY aims to achieve a good wavefront correction over a large field of view,…

Instrumentation and Methods for Astrophysics · Physics 2022-02-25 Bernadett Stadler , Ronny Ramlau

Knowledge of the optical turbulence profile is important in adaptive optics (AO) systems, particularly tomographic AO systems such as those to be employed by the next generation of 40 m class extremely large telescopes (ELTs). Site…

Instrumentation and Methods for Astrophysics · Physics 2018-09-26 O. J. D. Farley , J. Osborn , T. Morris , M. Sarazin , T. Butterley , M. J. Townson , P. Jia , R. W. Wilson

The resolution and contrast of microscope imaging is often affected by aberrations introduced by imperfect optical systems and inhomogeneous refractive structures in specimens. Adaptive optics (AO) compensates these aberrations and restores…

This letter studies the low-complexity channel estimation for orthogonal time frequency space (OTFS) in the presence of hardware impairments. Firstly, to tackle the computational complexity of channel estimation, the basis expansion model…

Signal Processing · Electrical Eng. & Systems 2025-02-07 Haowei Wu , Huanyu Chen , Qihao Peng , Qu Luo , Jinglan Ou

In tomographic reconstruction, the goal is to reconstruct an unknown object from a collection of line integrals. Given a complete sampling of such line integrals for various angles and directions, explicit inverse formulas exist to…

Numerical Analysis · Mathematics 2018-01-18 Tristan van Leeuwen , Simon Maretzke , K. Joost Batenburg

For natural guide start adaptive optics (AO) systems, pyramid wavefront sensors (PWFSs) can provide significant increase in sensitivity over the traditional Shack-Hartmann, but at the cost of a reduced linear range. When using a linear…

Instrumentation and Methods for Astrophysics · Physics 2023-12-05 Finn Archinuk , Rehan Hafeez , Sébastien Fabbro , Hossen Teimoorinia , Jean-Pierre Véran

To reduce scanning time and/or improve spatial/temporal resolution in some MRI applications, parallel MRI (pMRI) acquisition techniques with multiple coils acquisition have emerged since the early 1990s as powerful 3D imaging methods that…

Optimization and Control · Mathematics 2009-09-03 Lotfi Chaari , Jean-Christophe Pesquet , Philippe Ciuciu , Amel Benazza-Benyahia

Modern electron tomography has progressed to higher resolution at lower doses by leveraging compressed sensing methods that minimize total variation (TV). However, these sparsity-emphasized reconstruction algorithms introduce tunable…

Medical Physics · Physics 2023-09-12 William Millsaps , Jonathan Schwartz , Zichao Wendy Di , Yi Jiang , Robert Hovden

For reconstruction of low-rank matrices from undersampled measurements, we develop an iterative algorithm based on least-squares estimation. While the algorithm can be used for any low-rank matrix, it is also capable of exploiting a-priori…

Statistics Theory · Mathematics 2012-06-13 Dave Zachariah , Martin Sundin , Magnus Jansson , Saikat Chatterjee

Super-Resolution (SR) is a technique that seeks to upscale the resolution of a set of measured signals. SR retrieves higher-frequency signal content by combining multiple lower resolution sampled data sets. SR is well known both in the…

Instrumentation and Methods for Astrophysics · Physics 2022-11-09 Sylvain Oberti , Carlos Correia , Thierry Fusco , Benoit Neichel , Pierre Guiraud
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