High SNR measurement of interaction matrix on-sky and in lab

Esposito, Simone; Tubbs, Robert N.; Puglisi, Alfio; Oberti, Sylvain; Tozzi, A.; Xompero, Marco; Zanotti, D.

doi:10.1117/12.673514

Cited by 17 publications

(11 citation statements)

References 5 publications

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“…t are the commands computed after i iterations using D opt , D m , D t in equation (6). Table III Let D ∈ R ny×nu be the IM; this is the interaction matrix after having removed the columns corresponding to nonactive actuators, as described in subsection V-B.…”

Section: Iterative Methods For Sparse Matricesmentioning

confidence: 99%

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Sparse calibration of an extreme Adaptive Optics system

Chiuso

Muradore

Aller-Carpentier

2010

49th IEEE Conference on Decision and Control (CDC)

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Adaptive optics systems are extensively used in astronomy to obtain high resolution pictures of stars and galaxies with ground telescopes. The crucial point is to shape deformable mirrors in order to compensate for the incoming wave distorted by the atmospheric turbulence. The calibration of the system is the cornerstone to obtain good performance. The next generation of adaptive optics system, eXtreme Adaptive Optics (XAO), will have a very large number of actuators and sensors (∼ 10 4 ) in order to guarantee high Strehl ratio and contrast levels; as such computational burden could become a serious bottleneck. For this reason several iterative methods have been proposed in the last decade. Since convergence and computational complexity of these methods depend on the sparsity of the interaction matrix (matrix projecting commands into measurements), the problem of calibrating an XAO system forcing the interaction matrix to be as sparse as possible is clearly important. In this paper we propose a method based on the LASSO regression algorithm that solves efficiently this problem.

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Section: Iterative Methods For Sparse Matricesmentioning

confidence: 99%

“…This static approximation is A called Interaction Matrix (IM) and is usually obtained during the calibration phase when a particular pattern based on the Hadamard matrix is used as inputs, [11]. Other approaches have appeared recently, see [13], [6].…”

Section: Introductionmentioning

confidence: 99%

Sparse calibration of an extreme Adaptive Optics system

Chiuso

Muradore

Aller-Carpentier

2010

49th IEEE Conference on Decision and Control (CDC)

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“…18,19 It was important for us to make sure the complex LGS WFS mechanisms, or system flexure issues, were not inducing mis-registration from pointing to pointing or while following an object. Indeed, the LGS WFS mechanism are in constant motion to counteract the variation of range to the LGS, a consequence of the change in telescope elevation.…”

Section: On-sky Misregistration Calibrationsmentioning

confidence: 99%

GeMS: first on-sky results

et al. 2012

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GeMS, the Gemini Laser Guide Star Multi-Conjugate Adaptive Optics facility system, has seen first light in December 2011, and has already produced images with H band Strehl ratio in excess of 35% over fields of view of 85x85 arcsec, fulfilling the MCAO promise. In this paper, we report on these early results, analyze trends in performance, and concentrate on key or novel aspects of the system, like centroid gain estimation, on-sky noncommon path aberration estimation. We also present the first astrometric analysis, showing very encouraging results.

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“…Some methods have already been identified to achieve the measurements. The first approach consists of measuring the interaction matrix on-sky (Wildi & Brusa (2004), Esposito et al (2006), Pieralli et al (2008, Pinna et al (2012), Kellerer et al (2012)) while the second idea is to generate it synthetically using an AO simulator, injecting experimental inputs , Kolb et al (2012b), Kolb et al (2012a)). A summary of the classical procedure and of some of these new strategies is developed in Section 2.…”

Section: Introductionmentioning

confidence: 99%

A new calibration strategy for adaptive telescopes with pyramid WFS

Heritier

Esposito

Fusco

et al. 2018

Monthly Notices of the Royal Astronomical Society

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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 artificial calibration source for the interaction matrix measurement. Moreover, the optical propagation between the DM and the Wave-Front Sensor (WFS) may evolve during the operation, resulting in mis-registrations that highly affect the AO performance and thus the scientific observation. They have to be measured and compensated, for instance by updating the calibration. A new strategy consists of estimating the mis-registrations and injecting them into synthetic models to generate noise-free interaction matrices. This pseudo-synthetic approach is the baseline for the Adaptive Optics Facility working with a Shack-Hartmann WFS and seems particularly suited for the future Extremely Large Telescope as the calibration will have to be regularly updated, for a large numbers of actuators. In this paper, the feasibility of a pseudo synthetic calibration with Pyramid WFS at the Large Binocular Telescope (LBT) is investigated. A synthetic model of the LBT AO systems is developed, and the procedure to adjust the mis-registrations parameters is introduced, extracting them from an experimental interaction matrix. We successfully tested an interaction matrix generated from the model on the real system in high-order AO mode. We recorded a slightly better performance with respect to the experimental one. This work demonstrates that a high accuracy calibration can be obtained using the pseudo synthetic approach with pyramid WFS.

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High SNR measurement of interaction matrix on-sky and in lab

Cited by 17 publications

References 5 publications

Sparse calibration of an extreme Adaptive Optics system

Sparse calibration of an extreme Adaptive Optics system

GeMS: first on-sky results

A new calibration strategy for adaptive telescopes with pyramid WFS

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