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Ground-based high contrast imaging (HCI) and extreme adaptive optics (AO) technologies have advanced to the point of enabling direct detections of gas-giant exoplanets orbiting beyond the snow lines around nearby young star systems.…

Image retrieval-based cross-view localization methods often lead to very coarse camera pose estimation, due to the limited sampling density of the database satellite images. In this paper, we propose a method to increase the accuracy of a…

Computer Vision and Pattern Recognition · Computer Science 2023-07-21 Yujiao Shi , Fei Wu , Akhil Perincherry , Ankit Vora , Hongdong Li

We consider the mathematical background of the wavefront sensor type that is widely used in Adaptive Optics systems for astronomy, microscopy, and ophthalmology. The theoretical analysis of the pyramid sensor forward operators presented in…

Instrumentation and Methods for Astrophysics · Physics 2019-05-01 Victoria Hutterer , Ronny Ramlau , Iuliia Shatokhina

The Earth's atmosphere is comprised of turbulent layers that result in speckled and blurry images from ground-based visible and infrared observations. Adaptive Optics (AO) systems are employed to measure the perturbed wavefront with a…

Instrumentation and Methods for Astrophysics · Physics 2024-10-03 Zhenxi Du , Saavidra Perera , Daniel Levinstein , Quinn Konopacky , Alex Madurowicz , Bruce Macintosh , Lisa Poyneer , Richard Wilson , Ollie Farley

One of the major limitations of adaptive optics (AO) corrected image post-processing is the lack of knowledge on the system point spread function (PSF). The PSF is not always available as a direct imaging on isolated point like objects such…

Instrumentation and Methods for Astrophysics · Physics 2020-07-22 Romain Fétick , Laurent Mugnier , Thierry Fusco , Benoit Neichel

Optical imperfections, misalignments, aberrations, and even dust can significantly limit sensitivity in high-contrast imaging systems such as coronagraphs. An upstream deformable mirror (DM) in the pupil can be used to correct or compensate…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Johanan L. Codona , Matthew Kenworthy

Accurate measurement of polarization in spectral lines is important for the reliable inference of magnetic fields on the Sun. For ground based observations, polarimetric precision is severely limited by the presence of Earth's atmosphere.…

Instrumentation and Detectors · Physics 2012-11-05 K. Nagaraju , Alex Feller

Context. Adaptive optics (AO) systems greatly increase the resolution of large telescopes, but produce complex point spread function (PSF) shapes, varying in time and across the field of view. This PSF must be accurately known since it…

Time-delay error is a significant error source in adaptive optics (AO) systems. It arises from the latency between sensing the wavefront and applying the correction. Predictive control algorithms reduce the time-delay error, providing…

Instrumentation and Methods for Astrophysics · Physics 2024-06-27 Jalo Nousiainen , Juha-Pekka Puska , Tapio Helin , Nuutti Hyvönen , Markus Kasper

Transformer architecture has been showing its great strength in visual object tracking, for its effective attention mechanism. Existing transformer-based approaches adopt the pixel-to-pixel attention strategy on flattened image features and…

Computer Vision and Pattern Recognition · Computer Science 2022-05-10 Zikai Song , Junqing Yu , Yi-Ping Phoebe Chen , Wei Yang

Over the last few years increasing consideration has been given to the study of Laser Guide Stars (LGS) for the measurement of the disturbance introduced by the atmosphere in optical and near-infrared astronomical observations from the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 L. Schreiber , I. Foppiani , C. Robert , E. Diolaiti , J. -M. Conan , M. Lombini

The next generation of extreme adaptive optics (AO) must be calibrated exceptionally well to achieve the desired contrast for ground-based direct imaging exoplanet targets. Current wavefront sensing and control system responses deviate from…

The success of ground-based instruments for high contrast exoplanet imaging depends on the degree to which adaptive optics (AO) systems can mitigate atmospheric turbulence. While modern AO systems typically suffer from millisecond time lags…

Instrumentation and Methods for Astrophysics · Physics 2019-09-13 Rebecca Jensen-Clem , Charlotte Z. Bond , Sylvain Cetre , Eden McEwen , Peter Wizinowich , Sam Ragland , Dimitri Mawet , James Graham

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…

Instrumentation and Methods for Astrophysics · Physics 2023-07-05 Roland Wagner , Jenny Niebsch , Ronny Ramlau

We propose a new algorithm, for parameter estimation that is applicable to imaging using moving and synthetic aperture arrays. The new method results in higher resolution and more accurate estimation than commonly used methods when strong…

Instrumentation and Methods for Astrophysics · Physics 2010-08-31 Ronny Levanda , Amir Leshem

We present the photometric calibration of the HST Advanced Camera for Surveys (ACS). We give here an overview of the performance and calibration of the 2 CCD cameras, the Wide Field Channel (WFC) and the High Resolution Channel (HRC), and a…

In typical adaptive optics applications, the atmospheric residual turbulence affects the wavefront sensor response decreasing its sensitivity. On the other hand, wavefront sensors are generally calibrated in diffraction limited condition,…

Instrumentation and Methods for Astrophysics · Physics 2023-10-10 Guido Agapito , Carmelo Arcidiacono , Simone Esposito

Ground-based solar observations are severely affected by Earth's turbulent atmosphere. As a consequence, observed image quality and prevailing seeing conditions are closely related. Partial correction of image degradation is nowadays…

Instrumentation and Methods for Astrophysics · Physics 2021-02-10 Robert Kamlah , Meetu Verma , Andrea Diercke , Carsten Denker

Ground-based high contrast exoplanet imaging requires state-of-the-art adaptive optics (AO) systems in order to detect extremely faint planets next to their brighter host stars. For such extreme AO systems (with high actuator count…

Earth and Planetary Astrophysics · Physics 2022-08-02 J. Fowler , Maaike A. M. Van Kooten , Rebecca Jensen-Clem

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…

Instrumentation and Methods for Astrophysics · Physics 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