End to end optical design and wavefront error simulation of METIS

2018 ◽  
Author(s):  
Tibor Agócs ◽  
Willem Jellema ◽  
Joost van den Born ◽  
Rik ter Horst ◽  
Peter Bizenberger ◽  
...  
Keyword(s):  
Optical Design ◽  
Wavefront Error ◽  
End To End ◽  
Error Simulation

scholarly journals End-to-End Image Simulator for Optical Imaging Systems: Equations and Simulation Examples

2013 ◽  
Vol 2013 ◽  
pp. 1-23 ◽  
Author(s):  
Peter Coppo ◽  
Leandro Chiarantini ◽  
Luciano Alparone
Keyword(s):  
Optical Design ◽  
Software Tool ◽  
Intrinsic Noise ◽  
Classification Performance ◽  
Theoretical Description ◽  
Hyperspectral Data ◽  
Software Environment ◽  
Future Design ◽  
Optical Instruments ◽  
End To End

The theoretical description of a simplified end-to-end software tool for simulation of data produced by optical instruments, starting from either synthetic or airborne hyperspectral data, is described and some simulation examples of hyperspectral and panchromatic images for existing and future design instruments are also reported. High spatial/spectral resolution images with low intrinsic noise and the sensor/mission specifications are used as inputs for the simulations. The examples reported in this paper show the capabilities of the tool for simulating target detection scenarios, data quality assessment with respect to classification performance and class discrimination, impact of optical design on image quality, and 3D modelling of optical performances. The simulator is conceived as a tool (during phase 0/A) for the specification and early development of new Earth observation optical instruments, whose compliance to user’s requirements is achieved through a process of cost/performance trade-off. The Selex Galileo simulator, as compared with other existing image simulators for phase C/D projects of space-borne instruments, implements all modules necessary for a complete panchromatic and hyper spectral image simulation, and it allows excellent flexibility and expandability for new integrated functions because of the adopted IDL-ENVI software environment.

Differentiable Compound Optics and Processing Pipeline Optimization for End-to-end Camera Design

2021 ◽  
Vol 40 (2) ◽  
pp. 1-19
Author(s):  
Ethan Tseng ◽  
Ali Mosleh ◽  
Fahim Mannan ◽  
Karl St-Arnaud ◽  
Avinash Sharma ◽  
...  
Keyword(s):  
Neural Network ◽  
Image Processing ◽  
Optical Design ◽  
Neural Nets ◽  
Fine Tuning ◽  
Optical Systems ◽  
Design Tools ◽  
End To End ◽  
Application Specific ◽  
Network Processing

Most modern commodity imaging systems we use directly for photography—or indirectly rely on for downstream applications—employ optical systems of multiple lenses that must balance deviations from perfect optics, manufacturing constraints, tolerances, cost, and footprint. Although optical designs often have complex interactions with downstream image processing or analysis tasks, today’s compound optics are designed in isolation from these interactions. Existing optical design tools aim to minimize optical aberrations, such as deviations from Gauss’ linear model of optics, instead of application-specific losses, precluding joint optimization with hardware image signal processing (ISP) and highly parameterized neural network processing. In this article, we propose an optimization method for compound optics that lifts these limitations. We optimize entire lens systems jointly with hardware and software image processing pipelines, downstream neural network processing, and application-specific end-to-end losses. To this end, we propose a learned, differentiable forward model for compound optics and an alternating proximal optimization method that handles function compositions with highly varying parameter dimensions for optics, hardware ISP, and neural nets. Our method integrates seamlessly atop existing optical design tools, such as Zemax . We can thus assess our method across many camera system designs and end-to-end applications. We validate our approach in an automotive camera optics setting—together with hardware ISP post processing and detection—outperforming classical optics designs for automotive object detection and traffic light state detection. For human viewing tasks, we optimize optics and processing pipelines for dynamic outdoor scenarios and dynamic low-light imaging. We outperform existing compartmentalized design or fine-tuning methods qualitatively and quantitatively, across all domain-specific applications tested.

scholarly journals Design of pre-optics for laser guide star wavefront sensor for the ELT

2017 ◽  
Vol 6 (6) ◽  
Author(s):  
Eduard Muslimov ◽  
Kjetil Dohlen ◽  
Benoit Neichel ◽  
Emmanuel Hugot
Keyword(s):  
Optical Design ◽  
Laser Guide Star ◽  
Wavefront Sensors ◽  
Incoming Beam ◽  
Wavefront Error ◽  
Integral Field Spectrograph ◽  
Guide Star ◽  
Laser Guide ◽  
Light Integral ◽  
Integral Field

AbstractIn the present paper, we consider the optical design of a zoom system for the active refocusing in laser guide star wavefront sensors. The system is designed according to the specifications coming from the Extremely Large Telescope (ELT)-HARMONI instrument, the first-light, integral field spectrograph for the European (E)-ELT. The system must provide a refocusing of the laser guide as a function of telescope pointing and large decentring of the incoming beam. The system considers four moving lens groups, each of them being a doublet with one aspherical surface. The advantages and shortcomings of such a solution in terms of the component displacements and complexity of the surfaces are described in detail. It is shown that the system can provide the median value of the residual wavefront error of 13.8–94.3 nm and the maximum value <206 nm, while the exit pupil distortion is 0.26–0.36% for each of the telescope pointing directions.

scholarly journals Numerical estimation of wavefront error breakdown in adaptive optics

2018 ◽  
Vol 616 ◽  
pp. A102 ◽  
Author(s):  
F. Ferreira ◽  
E. Gendron ◽  
G. Rousset ◽  
D. Gratadour
Keyword(s):  
Adaptive Optics ◽  
Graphics Processing Units ◽  
Iteration Step ◽  
Simulation Code ◽  
Computing Platform ◽  
Error Covariance ◽  
Wavefront Error ◽  
End To End ◽  
Processing Techniques ◽  
Graphics Processing

Aims. Adaptive optics (AO) system performance is improved using post-processing techniques, such as point spread function (PSF) deconvolution. The PSF estimation involves characterization of the different wavefront (WF) error sources in the AO system. We propose a numerical error breakdown estimation tool that allows studying AO error source behavior such as their correlations. We also propose a new analytical model for anisoplanatism and bandwidth errors that were validated with the error breakdown estimation tool. This model is the first step for a complete AO residual error model that is expressed in deformable mirror space, leading to practical usage such as PSF reconstruction or turbulent parameters identification. Methods. We have developed in the computing platform for adaptive optics systems (COMPASS) code, which is an end-to-end simulation code using graphics processing units (GPU) acceleration, an estimation tool that provides a comprehensive error breakdown by the outputs of a single simulation run. We derive the various contributors from the end-to-end simulator at each iteration step: this method provides temporal buffers of each contributor. Then, we use this tool to validate a new model of anisoplanatism and bandwidth errors including their correlation. This model is based on a statistical approach that computes the error covariance matrices using structure functions. Results. On a SPHERE-like system, the comparison between a PSF computed from the error breakdown with a PSF obtained from classical end-to-end simulation shows that the statistics convergence limits converge very well, with a sub-percent difference in terms of Strehl ratio and ensquared energy at 5λ/D separation. A correlation analysis shows significant correlations between some contributors, especially WF measurement deviation error and bandwidth error due to centroid gain, and the well-known correlation between bandwidth and anisoplanatism errors is also retrieved. The model we propose for the two latter errors shows an SR and EE difference of about one percent compared to the end-to-end simulation, even if some approximations exist.

Single Crystal Piezoelectric Actuators for Advanced Deformable Mirrors

Aerospace ◽  
2004 ◽  
Author(s):  
X. N. Jiang ◽  
P. W. Rehrig ◽  
W. S. Hackenberger ◽  
J. Moore ◽  
S. Chodimella ◽  
...  
Keyword(s):  
Single Crystal ◽  
Adaptive Optics ◽  
System Modeling ◽  
Optical Design ◽  
Piezoelectric Actuators ◽  
Fast Response ◽  
Deformable Mirror ◽  
Wavefront Error ◽  
Single Crystal Plate ◽  
Rms Error

In this paper, single crystal piezoelectric actuators are developed and demonstrated as a means of increasing actuator authority while maintaining strain precision for adaptive optics used large throw deformable mirror applications. Single crystal (PMN-PT crystal) stack actuators with foot print size of 5 mm × 5 mm and height varied from 16 mm to 21 mm have been designed, fabricated and tested. The actuation stroke larger than 50 μm is obtained under driving electric field of 15 KV/cm for single crystal stack actuators. In-plane actuation stroke is about 25 μm under 8KV/cm for single crystal plate actuators. The characterization results show that the single crystal piezoelectric actuators hold enhanced stroke and coupling coefficient (&gt;0.83) under lower driving field comparing with PZT counterpart, while keep the nature of piezoelectric actuations with high precision, high resolution, fast response under high preload stress. The potential benefits of incorporating these actuators in a deformable mirror (DM) design were demonstrated by system modeling using the Integrated Optical Design Analysis Software (IODA) developed by SRS. The modeling shows that low order aberrations with peak to valley errors as large as 40 microns could be corrected to diffraction limited performance with a reasonable number of actuators and acceptable actuator forces and face sheet stresses. In the case of DM correction with 20 microns of 1st-Order Astigmatism-X error (Peak to valley: 38.74 μm, RMS error: 8.13 μm), the corrected wavefront error was reduced to PV of 0.26 μm and RMS error of 0.024 μm, which suggest promise for large throw DM applications.

Compact, Wide-Angle Catadioptric Telescope Design for MWIR Imaging

2019 ◽  
Vol 8 (1) ◽  
pp. 33-48
Author(s):  
Sami D Alaruri
Keyword(s):  
Focal Length ◽  
Optical Design ◽  
Tolerance Analysis ◽  
Optical Path Difference ◽  
Path Difference ◽  
Field Of View ◽  
Modulation Transfer ◽  
Full Field ◽  
Field Curvature ◽  
Wavefront Error

In this work, the optical design of a compact diffraction-limited F/3.0 MWIR (3-5 µm) catadioptric telescope which consists of an aspheric primary mirror, a spherical secondary mirror, a ZnSe-ZnSe-Ge triplet lens and an air-spaced Si-Ge-Si corrector triplet lens placed before the focus is given. The calculated effective focal length, full field of view (FFOV) and angular magnification values for the designed telescope are 600 mm, 2.6° and -9.2, respectively. Zemax® calculations for the telescope MTF (modulation transfer function), PSF (point spread function), RMS (root-mean-square) wavefront error (WFE), optical path difference (OPD), Seidel aberrations, encircled energy, distortion and field curvature are discussed. The telescope performance analysis indicates that the telescope can achieve diffraction-limited image quality performance within the 2.6° full field-of-view. Additionally, the designed telescope can resolve at 50% contrast spatial frequency equal to 18.5 cycles/mm (at the on-axis FOV). Finally, a detailed tolerance analysis for the telescope design employing Monte Carlo and sensitivity analysis simulation features in Zemax® is provided.

Use of the Magnetostatic Analogue In Electromagnetic Lens Engineering

1970 ◽  
Vol 28 ◽  
pp. 360-361
Author(s):  
John W. Coleman
Keyword(s):  
Boundary Conditions ◽  
High Performance ◽  
Force Fields ◽  
Optical Design ◽  
Direct Conversion ◽  
Design Engineering ◽  
Design Data ◽  
Scalar Potentials ◽  
Geometric Elements ◽  
At Will

In the design engineering of high performance electromagnetic lenses, the direct conversion of electron optical design data into drawings for reliable hardware is oftentimes difficult, especially in terms of how to mount parts to each other, how to tolerance dimensions, and how to specify finishes. An answer to this is in the use of magnetostatic analytics, corresponding to boundary conditions for the optical design. With such models, the magnetostatic force on a test pole along the axis may be examined, and in this way one may obtain priority listings for holding dimensions, relieving stresses, etc..The development of magnetostatic models most easily proceeds from the derivation of scalar potentials of separate geometric elements. These potentials can then be conbined at will because of the superposition characteristic of conservative force fields.

Surgical management of extracranial carotid artery aneurysms

VASA ◽  
2016 ◽  
Vol 45 (3) ◽  
pp. 223-228 ◽  
Author(s):  
Jan Paweł Skóra ◽  
Jacek Kurcz ◽  
Krzysztof Korta ◽  
Przemysław Szyber ◽  
Tadeusz Andrzej Dorobisz ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Surgical Management ◽  
Minor Stroke ◽  
Stroke Rate ◽  
Extracranial Carotid Artery ◽  
Long Term Follow Up ◽  
End To End ◽  
Dacron Patch ◽  
Major Stroke

Abstract. Background: We present the methods and results of the surgical management of extracranial carotid artery aneurysms (ECCA). Postoperative complications including early and late neurological events were analysed. Correlation between reconstruction techniques and morphology of ECCA was assessed in this retrospective study. Patients and methods: In total, 32 reconstructions of ECCA were performed in 31 symptomatic patients with a mean age of 59.2 (range 33 - 84) years. The causes of ECCA were divided among atherosclerosis (n = 25; 78.1 %), previous carotid endarterectomy with Dacron patch (n = 4; 12.5 %), iatrogenic injury (n = 2; 6.3 %) and infection (n = 1; 3.1 %). In 23 cases, intervention consisted of carotid bypass. Aneurysmectomy with end-to-end suture was performed in 4 cases. Aneurysmal resection with patching was done in 2 cases and aneurysmorrhaphy without patching in another 2 cases. In 1 case, ligature of the internal carotid artery (ICA) was required. Results: Technical success defined as the preservation of ICA patency was achieved in 31 cases (96.9 %). There was one perioperative death due to major stroke (3.1 %). Two cases of minor stroke occurred in the 30-day observation period (6.3 %). Three patients had a transient hypoglossal nerve palsy that subsided spontaneously (9.4 %). At a mean long-term follow-up of 68 months, there were no major or minor ipsilateral strokes or surgery-related deaths reported. In all 30 surviving patients (96.9 %), long-term clinical outcomes were free from ipsilateral neurological symptoms. Conclusions: Open surgery is a relatively safe method in the therapy of ECCA. Surgical repair of ECCAs can be associated with an acceptable major stroke rate and moderate minor stroke rate. Complication-free long-term outcomes can be achieved in as many as 96.9 % of patients. Aneurysmectomy with end-to-end anastomosis or bypass surgery can be implemented during open repair of ECCA.

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