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Context: Telescopes like the Extremely Large Telescope (ELT) and the Giant Magellan Telescope (GMT) will be used together with extreme adaptive optics (AO) instruments to directly image Earth-like planets. The AO systems will need to…

天体物理仪器与方法 · 物理学 2024-01-17 Sebastiaan Y. Haffert

Several telescopes include large Deformable Mirrors (DM) located directly inside the telescope. These adaptive telescopes trigger new constraints for the calibration of the Adaptive Optics (AO) systems as they usually offer no access to an…

天体物理仪器与方法 · 物理学 2019-01-10 C. T. Heritier , S. Esposito , T. Fusco , B. Neichel , S. Oberti , R. Briguglio , G. Agapito , A. Puglisi , E. Pinna , P. -Y. Madec

We address covariance estimation in the sense of minimum mean-squared error (MMSE) for Gaussian samples. Specifically, we consider shrinkage methods which are suitable for high dimensional problems with a small number of samples (large p…

统计方法学 · 统计学 2015-05-13 Yilun Chen , Ami Wiesel , Yonina C. Eldar , Alfred O. Hero

Astronomical telescopes suffer from a tradeoff between field of view (FoV) and image resolution: increasing the FoV leads to an optical field that is under-sampled by the science camera. This work presents a novel computational imaging…

天体物理仪器与方法 · 物理学 2025-08-07 Robin Swanson , Esther Y. H. Lin , Masen Lamb , Suresh Sivanandam , Kiriakos N. Kutulakos

Wave-front sensing from focal plane multiple images is a promising technique for high-contrast imaging systems. However, the wave-front error of an optics system can be properly reconstructed only when it is very small. This paper presents…

天体物理仪器与方法 · 物理学 2015-05-19 Jiangpei Dou , Deqing Ren , Yongtian Zhu

Recent theory of mapping an image into a structured low-rank Toeplitz or Hankel matrix has become an effective method to restore images. In this paper, we introduce a generalized structured low-rank algorithm to recover images from their…

图像与视频处理 · 电气工程与系统科学 2018-11-28 Yue Hu , Xiaohan Liu , Mathews Jacob

Continuous wavefront sensing on future space telescopes allows relaxation of stability requirements while still allowing on-orbit diffraction-limited optical performance. We consider the suitability of phase retrieval to continuously…

天体物理仪器与方法 · 物理学 2023-09-14 Hyukmo Kang , Kyle Van Gorkom , Jess Johnson , Ole Singlestad , Aaron Goldtooth , Daewook Kim , Ewan S. Douglas

Downlink beamforming is a key technology for cellular networks. However, computing the transmit beamformer that maximizes the weighted sum rate subject to a power constraint is an NP-hard problem. As a result, iterative algorithms that…

信号处理 · 电气工程与系统科学 2020-06-16 Lissy Pellaco , Mats Bengtsson , Joakim Jaldén

Accurate characterization of free-space optical (FSO) channels requires joint estimation of transmitter pointing errors, receiver angle-of-arrival (AoA) fluctuations, and turbulence-induced fading. However, existing literature addresses…

信号处理 · 电气工程与系统科学 2025-12-16 Mohammad Taghi Dabiri , Meysam Ghanbari , Rula Ammuri , Mazen Hasna , Khalid Qaraqe

We present a simple approximation that can speed up the computation of the mode-coupling matrices, which are usually the bottleneck for computing unbiased angular power spectra, as well as their associated covariance matrices, of the cosmic…

宇宙学与河外天体物理 · 物理学 2021-01-04 Thibaut Louis , Sigurd Naess , Xavier Garrido , Anthony Challinor

Minimum mean square error (MMSE) signal detection algorithm is near- optimal for uplink multi-user large-scale multiple input multiple output (MIMO) systems, but involves matrix inversion with high complexity. In this letter, we firstly…

信息论 · 计算机科学 2015-07-17 Xinyu Gao , Linglong Dai , Yongkui Ma , Zhaocheng Wang

PURPOSE: We develop a practical, iterative algorithm for image-reconstruction in under-sampled tomographic systems, such as digital breast tomosynthesis (DBT). METHOD: The algorithm controls image regularity by minimizing the image total…

Free-space optical communication (FSOC) systems offer high-bandwidth and secure communication with minimal capital costs. Adaptive optics (AO) are typically added to these systems to decrease atmospheric channel losses; however, the…

Total variation (TV) regularization is popular in image restoration and reconstruction due to its ability to preserve image edges. To date, most research activities on TV models concentrate on image restoration from blurry and noisy…

最优化与控制 · 数学 2010-01-13 Yunhai Xiao , Junfeng Yang

Large-scale multiple-input multiple-output (MIMO) is an emerging wireless technology that deploys thousands of transmit antennas at the base-station to boost spectral efficiency. The classic weighted minimum mean-square-error (WMMSE)…

信息论 · 计算机科学 2025-03-17 Yi Feng , Kaiming Shen

Particle beam microscopy uses a scanning beam of charged particles to create images of samples, and the quality of image reconstruction suffers when this beam current varies over time. Neither conventional reconstruction methods nor…

图像与视频处理 · 电气工程与系统科学 2021-06-10 Luisa Watkins

The image quality of the new generation of earthbound Extremely Large Telescopes (ELTs) is heavily influenced by atmospheric turbulences. To compensate these optical distortions a technique called adaptive optics (AO) is used. Many AO…

数值分析 · 数学 2020-09-03 Bernadett Stadler , Roberto Biasi , Mauro Manetti , Ronny Ramlau

We use telemetry data from the Gemini North ALTAIR adaptive optics system to investigate how well the commands for wavefront correction (both Tip/Tilt and high-order turbulence) can be forecasted in order to reduce lag error (due to…

天体物理仪器与方法 · 物理学 2022-05-16 Rehan Hafeez , Finn Archinuk , Sébastien Fabbro , Hossen Teimoorinia , Jean-Pierre Véran

This paper is concerned with the channel estimation problem in Millimeter wave (mmWave) wireless systems with large antenna arrays. By exploiting the inherent sparse nature of the mmWave channel, we first propose a fast channel estimation…

信息论 · 计算机科学 2016-11-17 Matthew Kokshoorn , He Chen , Peng Wang , Yonghui Li , Branka Vucetic

Modern Giant Segmented Mirror Telescopes (GSMTs) like the Extremely Large Telescope, which is currently under construction, depend heavily on Adaptive Optics (AO) systems to correct for atmospheric distortions. However, a residual blur…

天体物理仪器与方法 · 物理学 2023-07-05 Roland Wagner , Jenny Niebsch , Ronny Ramlau