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For segmented telescopes, achieving fine co-focus adjustment is essential for realizing co-phase adjustment and maintenance, which involves adjusting the millimeter-scale piston between segments to fall within the capture range of the…

Instrumentation and Methods for Astrophysics · Physics 2024-04-12 Kunyan Wang , Yichun Dai , Bin Wang , Xu Tan , Dehua Yang , Zhenyu Jin

Space coronagraphs are projected to detect exoplantes that are at least 1e10 times dimmer than their host stars. Yet, the actual detection threshold depends on the instrument's wavefront stability and varies by an order of magnitude with…

Instrumentation and Methods for Astrophysics · Physics 2020-06-18 Leonid Pogorelyuk , Laurent Pueyo , N. Jeremy Kasdin

We propose a compact snapshot monocular depth estimation technique that relies on an engineered point spread function (PSF). Traditional approaches used in microscopic super-resolution imaging such as the Double-Helix PSF (DHPSF) are…

Image and Video Processing · Electrical Eng. & Systems 2022-08-05 Bhargav Ghanekar , Vishwanath Saragadam , Dushyant Mehra , Anna-Karin Gustavsson , Aswin Sankaranarayanan , Ashok Veeraraghavan

Diffusion-weighted magnetic resonance imaging (DW-MRI) is a critical imaging method for capturing and modeling tissue microarchitecture at a millimeter scale. A common practice to model the measured DW-MRI signal is via fiber orientation…

The Near-Infrared Spectrograph (NIRSpec) is one of four science instruments on board the James Webb Space Telescope (JWST), which began routine operations in July 2022. As JWST's primary spectroscopic instrument for faint, distant targets,…

Instrumentation and Methods for Astrophysics · Physics 2025-08-20 Katie Bechtold , Torsten Böker , David E. Franz , Dennis Garland , Maurice te Plate , Timothy D. Rawle , Christopher Q. Trinh , Rai Wu , Peter Zeidler

Modern extreme adaptive optics (AO) systems achieving diffraction-limited performance open up new possibilities for instrumentation. Especially important for the fields of spectroscopy and interferometry is that it enables the prospect to…

This article demonstrates the realization of an extraordinary beam splitter based on nonreciprocal and synchronized photonic transitions in obliquely illuminated space-time-modulated (STM) slabs which impart the coherent temporal frequency…

Optics · Physics 2019-02-06 Sajjad Taravati , Ahmed A. Kishk

One of the fundamental limits of classical optical microscopy is the diffraction limit of optical resolution. It results from the finite bandwidth of the optical transfer function (or OTF) of an optical microscope, which restricts the…

Optics · Physics 2022-03-11 Sjoerd Stallinga , Niels Radmacher , Antoine Delon , Jörg Enderlein

Video temporal dynamics is conventionally modeled with 3D spatial-temporal kernel or its factorized version comprised of 2D spatial kernel and 1D temporal kernel. The modeling power, nevertheless, is limited by the fixed window size and…

Computer Vision and Pattern Recognition · Computer Science 2022-11-16 Fuchen Long , Zhaofan Qiu , Yingwei Pan , Ting Yao , Chong-Wah Ngo , Tao Mei

In Orthogonal Time Frequency Space (OTFS) modulation, information symbols are embedded in the delay-Doppler (DD) domain instead of the time-frequency (TF) domain. n order to ensure compatibility with existing OFDM systems (e.g. 4G LTE),…

Information Theory · Computer Science 2024-10-30 Saif Khan Mohammed

Doppler tomography is a method to compute the emissivity distribution within the co-rotating frames of binary stars from observations of their emission line profiles at multiple orbital phases. A key assumption of the method as it is…

Solar and Stellar Astrophysics · Physics 2021-12-08 T. R. Marsh

We investigate the focal plane wavefront sensing technique, known as Phase Diversity, at the scientific focal plane of a segmented mirror telescope with an adaptive optics (AO) system. We specifically consider an optical system imaging a…

Instrumentation and Methods for Astrophysics · Physics 2021-05-03 Masen Lamb , Carlos Correia , Suresh Sivanandam , Robin Swanson , Polina Zavyalova

In this paper, a generalized differentiation-integration observer is presented based on sensors selection. The proposed differentiation-integration observer can estimate the multiple integrals and high-order derivatives of a signal,…

Systems and Control · Computer Science 2017-05-25 Xinhua Wang , Lilong Cai

Delay-Doppler (DD) signal processing has emerged as a powerful tool for analyzing multipath and time-varying channel effects. Due to the inherent sparsity of the wireless channel in the DD domain, compressed sensing (CS) based techniques,…

Signal Processing · Electrical Eng. & Systems 2024-12-03 Hanning Wang , Xiang Huang , Rong-Rong Chen , Arman Farhang

Phase retrieval from phaseless short-time Fourier transform (STFT) measurements is known to be inherently unstable when measurements are taken with respect to a single window. While an explicit inversion formula exists, it is useless in…

Functional Analysis · Mathematics 2025-06-19 Rima Alaifari , Yunan Yang

High quality, repeatable point-spread functions are important for science cases like direct exoplanet imaging, high-precision astrometry, and high-resolution spectroscopy of exoplanets. For such demanding applications, the initial on-sky…

Instrumentation and Methods for Astrophysics · Physics 2021-07-19 Steven P. Bos , Michael Bottom , Sam Ragland , Jacques-Robert Delorme , Sylvain Cetre , Laurent Pueyo

The use of Fourier methods in wave-front reconstruction can significantly reduce the computation time for large telescopes with a high number of degrees of freedom. However, Fourier algorithms for discrete data require a rectangular data…

Instrumentation and Methods for Astrophysics · Physics 2017-06-07 Charlotte Z. Bond , Carlos M. Correia , Jean-François Sauvage , Benoit Neichel , Thierry Fusco

Ultra-reliable wireless communication links require the utilization of all diversity sources of a wireless communication channel. Hadani et al. propose a two dimensional discrete symplectic Fourier transform (DSFT) as orthogonal pre-coder…

Information Theory · Computer Science 2019-07-24 Thomas Zemen , Markus Hofer , David Loeschenbrand , Christoph Pacher

The development of new techniques for characterizing atmospheric optical turbulence (OT) has become an active topic of research again in recent years. In order to facilitate these studies, we reconsidered known theoretical results and…

Instrumentation and Methods for Astrophysics · Physics 2021-08-18 Victor Kornilov , Boris Safonov , Matwey Kornilov

Tilt-corrected imaging methods in four-dimensional scanning transmission electron microscopy (4D-STEM) have recently emerged as a new class of direct ptychography methods that are especially useful at low dose. The operation of tilt…

Optics · Physics 2025-10-03 Desheng Ma , David A Muller , Steven E Zeltmann