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Multi-object astronomical adaptive-optics (MOAO) is now a mature wide-field observation mode to enlarge the adaptive-optics-corrected field in a few specific locations over tens of arc-minutes. The work-scope provided by open-loop…

Instrumentation and Methods for Astrophysics · Physics 2023-07-19 Carlos M. Correia , Kate Jackson , Jean-Pierre Veran , David Andersen , Olivier Lardiere , Colin Bradley

Near-diffraction limited imaging and spectroscopy in the visible on large (8-10 meter) class telescopes has proved to be beyond the capabilities of current adaptive optics technologies, even when using laser guide stars. The need for high…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Craig Mackay , Tim D. Staley , David King , Frank Suess , Keith Weller

Spectral imaging is a fundamental diagnostic technique with widespread application. Conventional spectral imaging approaches have intrinsic limitations on spatial and spectral resolutions due to the physical components they rely on. To…

Image and Video Processing · Electrical Eng. & Systems 2021-06-07 Figen S. Oktem , Oğuzhan Fatih Kar , Can Deniz Bezek , Farzad Kamalabadi

We present the method of multiplexed imaging designed for astronomical observations of large sky areas in the IR, visible and UV frequencies. Our method relies on the sparse nature of astronomical observations. The method consists of an…

Instrumentation and Methods for Astrophysics · Physics 2014-03-11 Barak Zackay , Avishay Gal-Yam

Microscope objectives achieve near diffraction-limited performance only when used under the conditions they are designed for. In non-standard geometries, such as thick cover slips or curved surfaces, severe aberrations arise, inevitably…

Optics · Physics 2025-03-24 D. W. S. Cox , T. Knop , I. M. Vellekoop

Wide field-of-view (FOV) cameras, which capture a larger scene area than narrow FOV cameras, are used in many applications including 3D reconstruction, autonomous driving, and video surveillance. However, wide-angle images contain…

Computer Vision and Pattern Recognition · Computer Science 2021-12-02 Jinlong Fan , Jing Zhang , Stephen J. Maybank , Dacheng Tao

In addition to the optical aberrations, the magnitude of the optical cells of detectors is one of the most important parameters, which restricts the resolution of detectors. Adaptive optic and the methods of reducing the aberrations are…

Optics · Physics 2007-05-23 S. Khademi , A. Darudi , M. Shahsavari

Since its beginnings, diffraction-limited ground-based adaptive optics (AO) imaging has been limited to wavelengths in the near IR ({\lambda} > 1 micron) and longer. Visible AO ({\lambda} < 1 micron) has proven to be difficult because…

Instrumentation and Methods for Astrophysics · Physics 2010-08-03 Derek Kopon , Jared R. Males , Laird M. Close , Victor Gasho

One important frontier for astronomical adaptive optics (AO) involves methods such as Multi-Object AO and Multi-Conjugate AO that have the potential to give a significantly larger field of view than conventional AO techniques. A second key…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 S. Mark Ammons , Luke Johnson , Edward A. Laag , Renate Kupke , Donald T. Gavel , Brian J. Bauman , Claire E. Max

Adaptive Optics has become a key technology for the largest ground-based telescopes currently under or close to begin of construction. Adaptive optics is an indispensable component and has basically only one task, that is to operate the…

Instrumentation and Methods for Astrophysics · Physics 2019-01-24 Stefan Hippler

We describe the preliminary optimized layout for a partially optimized concept of an optical-8m class VLT-like 2x2 segmented camera where each channel is assisted by an equivalent of an MCAO system where the ground layer correction is…

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

Adaptive optics is a technique mostly used on large telescopes. It turns out to be challenging for smaller telescopes (0.5~2m) due to the small isoplanatic angle, small subapertures and high correction speeds needed at visible wavelengths,…

Instrumentation and Methods for Astrophysics · Physics 2023-10-12 Olivier Lai , Mark Chun , Stefan Kuiper , Niek Doelman , Marcel Carbillet , Mamadou N'Diaye , Frantz Martinache , Lyu Abe , Jean-Pierre Rivet , Dirk Schmidt

An holographic microscopy reconstruction method compatible with high numerical aperture microscope objective (MO) up to NA=1.4 is proposed. After off axis and reference field curvature corrections, and after selection of the +1 grating…

Optics · Physics 2015-11-16 Nicolas Verrier , Dario Donnarumma , Gilles Tessier , Michel Gross

Medical image segmentation is an important task for computer aided diagnosis. Pixelwise manual annotations of large datasets require high expertise and is time consuming. Conventional data augmentations have limited benefit by not fully…

Image and Video Processing · Electrical Eng. & Systems 2020-04-28 Dwarikanath Mahapatra , Behzad Bozorgtabar , Jean-Philippe Thiran , Ling Shao

Photographs taken with less-than-ideal exposure settings often display poor visual quality. Since the correction procedures vary significantly, it is difficult for a single neural network to handle all exposure problems. Moreover, the…

Computer Vision and Pattern Recognition · Computer Science 2023-12-19 Gehui Li , Jinyuan Liu , Long Ma , Zhiying Jiang , Xin Fan , Risheng Liu

We describe an adaptive optics technique for two-photon microscopy in which the deformable mirror used for aberration compensation is positioned in a plane conjugate to the plane of the aberration. We demonstrate in a proof-of-principle…

Optics · Physics 2023-07-19 Hari P. Paudel , John Taranto , Jerome Mertz , Thomas Bifano

Inhomogeneities in the refractive index of a biological sample can introduce phase aberrationsin microscopy systems, severely impairing the quality of images. Adaptive optics can be employed to correct for phase aberrations and improve…

The performance of an adaptive optics (AO) system on a 100m diameter ground based telescope working in the visible range of the spectrum is computed using an analytical approach. The target Strehl ratio of 60% is achieved at 0.5um with a…

Astrophysics · Physics 2009-10-31 M. Le Louarn , N. Hubin , M. Sarazin , A. Tokovinin

In this paper we broadly consider techniques which utilize projections on rays for data collection, with particular emphasis on optical techniques. We formulate a variety of imaging techniques as either special cases or extensions of…

Computer Vision and Pattern Recognition · Computer Science 2014-02-12 Keith Dillon , Yeshaiahu Fainman