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The pyramid wavefront sensor (PyWFS) has become increasingly popular to use in adaptive optics (AO) systems due to its high sensitivity. The main drawback of the PyWFS is that it is inherently nonlinear, which means that classic linear…

Instrumentation and Methods for Astrophysics · Physics 2023-11-07 Alison P. Wong , Barnaby R. M. Norris , Vincent Deo , Peter G. Tuthill , Richard Scalzo , David Sweeney , Kyohoon Ahn , Julien Lozi , Sebastien Vievard , Olivier Guyon

Almost all current and future high-contrast imaging instruments will use a Pyramid wavefront sensor (PWFS) as a primary or secondary wavefront sensor. The main issue with the PWFS is its nonlinear response to large phase aberrations,…

The sensitivity of the the pyramid wavefront sensor (PyWFS) has made it a popular choice for astronomical adaptive optics (AAO) systems, and it is at its most sensitive when it is used without modulation of the input beam. In non-modulated…

Instrumentation and Methods for Astrophysics · Physics 2018-05-09 Richard A. Frazin

Fourier-based wavefront sensors, such as the Pyramid Wavefront Sensor (PWFS), are the current preference for high contrast imaging due to their high sensitivity. However, these wavefront sensors have intrinsic nonlinearities that constrain…

Instrumentation and Methods for Astrophysics · Physics 2020-05-22 Rico Landman , Sebastiaan Haffert

Pyramid wavefront sensors (PWFSs) are the preferred choice for current and future extreme adaptive optics (XAO) systems. Almost all instruments use the PWFS in its modulated form to mitigate its limited linearity range. However, this…

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

Extreme adaptive optics (AO) is crucial for enabling the contrasts needed for ground-based high contrast imaging instruments to detect exoplanets. Pushing exoplanet imaging detection sensitivities towards lower mass, closer separations, and…

Earth and Planetary Astrophysics · Physics 2021-07-29 Benjamin L. Gerard , Vincent Chambouleyron , Rebecca Jensen-Clem , Jean-François Sauvage

Most adaptive optics (AO) systems using pyramid wavefront sensors (PyWFS) to estimate the phase of the pupil field use mechanical modulation of the beam in order to increase the dynamic range in low-order modes so the PyWFS can usefully…

Instrumentation and Methods for Astrophysics · Physics 2017-08-31 Richard Frazin

State-of-the-art adaptive optics (AO) systems perform non-linear Fourier-type wavefront sensing for real-time corrections of dynamic wavefront aberrations. This general class of sensors uses a filtering mask in the focal plane that converts…

Instrumentation and Methods for Astrophysics · Physics 2025-06-24 Victoria Laidlaw

Extremely Large Telescopes have overwhelmingly opted for the Pyramid wavefront sensor (PyWFS) over the more widely used Shack-Hartmann WaveFront Sensor (SHWFS) to perform their Single Conjugate Adaptive Optics (SCAO) mode. The PyWFS, a…

Instrumentation and Methods for Astrophysics · Physics 2020-11-25 Vincent Chambouleyron , Olivier Fauvarque , Pierre Janin-Potiron , Carlos Correia , Jean-François Sauvage , Noah Schwartz , Benoît Neichel , Thierry Fusco

Context. The diffusion of adaptive optics systems in astronomical instrumentation for large ground-based telescopes is rapidly increasing and the pyramid wavefront sensor is replacing the Shack-Hartmann as the standard solution for single…

Instrumentation and Methods for Astrophysics · Physics 2023-09-27 Guido Agapito , Enrico Pinna , Simone Esposito , Cedric Taïssir Heritier , Sylvain Oberti

Adaptive optics (AO) is a technique to improve the resolution of ground-based telescopes by correcting, in real-time, optical aberrations due to atmospheric turbulence and the telescope itself. With the rise of Giant Segmented Mirror…

Advanced AO systems will likely utilise Pyramid wave-front sensors (PWFS) over the traditional Shack-Hartmann sensor in the quest for increased sensitivity, peak performance and ultimate contrast. Here, we wish to bring knowledge and…

Instrumentation and Methods for Astrophysics · Physics 2020-06-17 Carlos M. Correia , Olivier Fauvarque , Charlotte Z. Bond , Vincent Chambouleyron , Jean-Francois Sauvage , Thierry Fusco

The pyramid wavefront sensor (P-WFS) has replaced the Shack-Hartmann (SH-) WFS as sensor of choice for high performance adaptive optics (AO) systems in astronomy because of its flexibility in pupil sampling, its dynamic range, and its…

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

Although using convolutional neural networks (CNNs) as backbones achieves great successes in computer vision, this work investigates a simple backbone network useful for many dense prediction tasks without convolutions. Unlike the…

Computer Vision and Pattern Recognition · Computer Science 2021-08-12 Wenhai Wang , Enze Xie , Xiang Li , Deng-Ping Fan , Kaitao Song , Ding Liang , Tong Lu , Ping Luo , Ling Shao

Convolutional neural networks (CNNs) have been the de facto standard in a diverse set of computer vision tasks for many years. Especially, deep neural networks based on seminal architectures such as U-shaped models with skip-connections or…

Image and Video Processing · Electrical Eng. & Systems 2022-08-02 Reza Azad , Moein Heidari , Moein Shariatnia , Ehsan Khodapanah Aghdam , Sanaz Karimijafarbigloo , Ehsan Adeli , Dorit Merhof

With its high sensitivity, the Pyramid wavefront sensor (PyWFS) is becoming an advantageous sensor for astronomical adaptive optics (AO) systems. However, this sensor exhibits significant non-linear behaviours leading to challenging AO…

Instrumentation and Methods for Astrophysics · Physics 2021-05-12 Vincent Chambouleyron , Olivier Fauvarque , Jean-François Sauvage , Benoît Neichel , Thierry Fusco

We propose a novel control approach that combines offline supervised learning to address the challenges posed by non-linear phase reconstruction using unmodulated pyramid wavefront sensors (P-WFS) and online reinforcement learning for…

Instrumentation and Methods for Astrophysics · Physics 2024-05-24 Bartomeu Pou , Jeffrey Smith , Eduardo Quinones , Mario Martin , Damien Gratadour

Super-resolution (SR) refers to a combination of optical design and signal processing techniques jointly employed to obtain reconstructed wave-fronts at a higher-resolution from multiple low-resolution samples, overcoming the intrinsic…

Instrumentation and Methods for Astrophysics · Physics 2025-12-22 Carlos M. Correia , Charlotte Z. Bond , João Aveiro , François Leroux , Cédric Taïssir Heritier , Christophe Vérinaud
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