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Optical aberrations prevent telescopes from reaching their theoretical diffraction limit. Once estimated, these aberrations can be compensated for using deformable mirrors in a closed loop. Focal plane wavefront sensing enables the…

In recent years, computational Time-of-Flight (ToF) imaging has emerged as an exciting and a novel imaging modality that offers new and powerful interpretations of natural scenes, with applications extending to 3D, light-in-flight, and…

Image and Video Processing · Electrical Eng. & Systems 2024-11-05 Ruiming Guo , Ayush Bhandari

The efficiency of the management of top-class ground-based astronomical facilities supported by Adaptive Optics (AO) relies on our ability to forecast the optical turbulence (OT) and a set of relevant atmospheric parameters. Indeed, in…

Instrumentation and Methods for Astrophysics · Physics 2020-06-14 E. Masciadri , G. Martelloni , A. Turchi

Several Wide Field of view Adaptive Optics (WFAO) concepts like Multi-Conjugate AO (MCAO), Multi-Object AO (MOAO) or Ground-Layer AO (GLAO) are currently studied for the next generation of Extremely Large Telescopes (ELTs). All these…

Astrophysics · Physics 2009-11-13 B. Neichel , T. Fusco , J. -M. Conan

When inverting solar spectra, image degradation effects that are present in the data are usually approximated or not considered. We develop a data reduction method that takes these issues into account and minimizes the resulting errors. By…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 M. van Noort

The future large adaptive telescopes will trigger new constraints for the calibration of Adaptive Optics (AO) systems equipped with pre-focal Deformable Mirrors (DM). The image of the DM actuators grid as seen by the Wave-Front Sensor (WFS)…

Instrumentation and Methods for Astrophysics · Physics 2021-05-26 C. T. Heritier , T. Fusco , S. Oberti , B. Neichel , S. Esposito , P. -Y. Madec

Bright single and binary stars were observed at the 4.1-m telescope with a fast electron-multiplication camera in the regime of partial turbulence correction by the visible-light adaptive optics system. We compare the angular resolution…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 A. Tokovinin , R. Cantarutti , R. Tighe , P. Schurter , N. van der Bliek , M. Martinez , E. Mondaca

In image deconvolution problems, the diagonalization of the underlying operators by means of the FFT usually yields very large speedups. When there are incomplete observations (e.g., in the case of unknown boundaries), standard…

Computer Vision and Pattern Recognition · Computer Science 2016-08-31 Miguel Simões , Luis B. Almeida , José Bioucas-Dias , Jocelyn Chanussot

Radial velocity instruments require high spectral resolution and extreme thermo-mecanical stability, even more difficult to achieve in near-infra red (NIR) where the spectrograph has to be cooled down. For a seeing-limited spectrograph, the…

Instrumentation and Methods for Astrophysics · Physics 2016-11-23 Uriel Conod , Nicolas Blind , François Wildi , Francesco Pepe

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

The most ubiquitous form of computational aberration correction for microscopy is deconvolution. However, deconvolution relies on the assumption that the point spread function is the same across the entire field-of-view. This assumption is…

Image and Video Processing · Electrical Eng. & Systems 2025-04-30 Amit Kohli , Anastasios N. Angelopoulos , David McAllister , Esther Whang , Sixian You , Kyrollos Yanny , Federico M. Gasparoli , Bo-Jui Chang , Reto Fiolka , Laura Waller

Optical stellar interferometers have demonstrated milli-arcsecond resolution with few apertures spaced hundreds of meters apart. To obtain rich direct images, many apertures will be needed, for a better sampling of the incoming wavefront.…

Instrumentation and Methods for Astrophysics · Physics 2014-09-17 Arun Surya , Swapan K. Saha , Antoine Labeyrie

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…

Signal Processing · Electrical Eng. & Systems 2025-12-16 Mohammad Taghi Dabiri , Meysam Ghanbari , Rula Ammuri , Mazen Hasna , Khalid Qaraqe

In the case of ground-based telescopes equipped with adaptive optics systems, the point spread function (PSF) is only poorly known or completely unknown. Moreover, an accurate modeling of the PSF is in general not available. Therefore in…

Numerical Analysis · Mathematics 2015-06-09 M. Prato , A. La Camera , S. Bonettini , S. Rebegoldi , M. Bertero , P. Boccacci

Few-shot anomaly detection (FSAD) plays a crucial role in industrial manufacturing. However, existing FSAD methods encounter difficulties leveraging a limited number of normal samples, frequently failing to detect and locate inconspicuous…

Computer Vision and Pattern Recognition · Computer Science 2024-10-02 Yuhu Bai , Jiangning Zhang , Zhaofeng Chen , Yuhang Dong , Yunkang Cao , Guanzhong Tian

High-contrast imaging and spectroscopy provide unique constraints for exoplanet formation models as well as for planetary atmosphere models. Instrumentation techniques in this field have greatly improved over the last two decades, with the…

Instrumentation and Methods for Astrophysics · Physics 2017-12-20 Johan Mazoyer , Laurent Pueyo , Mamadou N'Diaye , Kevin Fogarty , Neil Zimmerman , Rémi Soummer , Stuart Shaklan , Colin Norman

The implementation of efficient free-space channels is fundamental for both classical and quantum Free-Space Optical (FSO) communication. This can be challenging for fibre-coupled receivers, due to the time variant inhomogeneity of the…

In many mechanical, electrical, and general physical systems evolving over time or space, spectral analysis methods as Fast Fourier Transform (FFT), Short Term Fourier Transform (STFT), Power Spectrum Density (PSD) plays a very important…

Signal Processing · Electrical Eng. & Systems 2023-06-21 Andreas Tuor , Nico Canzani , Tobias Rüggeberg , Stefan Gorenflo , Gerd Simons , Bruno Bättig , Daniel Iseli

We demonstrate that accurate computation of the spectral proper orthogonal decomposition (SPOD) critically depends on the choice of frequency resolution. Using both artificially generated data and large-eddy simulation data of a turbulent…

Fluid Dynamics · Physics 2024-02-27 Liam Heidt , Tim Colonius

Diffraction-limited imaging in epi-fluorescence microscopy remains a challenge when sample aberrations are present or when the region of interest rests deep within an inhomogeneous medium. Adaptive optics is an attractive solution albeit…