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Passive Sensors 1991

作者： Vollmerhausen, Richard H. Nash, Carolyn J. US Army CECOM Center for Night Vision and Electro-Optics Fort BelvoirVA United States

The Army requirement to fly helicopters at low level at night led to the development and fielding of night vision pilotage sensors. These sensors have included image intensifiers (I2) operating in the near infrared as well as 8 to 12 micron thermal imagers. The design of current pilotage sensors was driven by available technology. There were no clear data for optimum pilotage sensor design, to enable the designer to trade off sensor field of view (FOV) and resolution or to predict the performance increase which could be obtained by increasing sensitivity. The current Center for Night Vision and Electro-Optics (CCNVEO) effort is an attempt to establish design criteria for night pilotage sensors. It includes flight experiments to find sensor characteristics which optimize flight tasks as well as assessments of the performance of fielded systems. We conclude that terrain flight can be accomplished with reasonable pilot workload using a sensor with 40 degree FOV and 0.6 cycles per mi 11iradian (cy/mrad) resolution. Larger FOV or better resolution will lesson workload and improve confidence;however, the ability to resolve scene detail of 0.6 cy/mrad is essential and should not be traded for increased FOV. Further, a pilotage system which provides both thermal and I2 imagery will significantly enhance system capability to support a variety of flight tasks under a wide range of environments. We also conclude that solid state cameras with detector dwell time equal to the standard video field rate are not suitable for use in pilotage systems. The long dwell time leads to image blur due to the head and scene motion associated with many pilotage tasks. © (1992) 2017 SPIE.

关键词： Image enhancement

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optical design and Predicted Performance of the WFIRST Phase-B Imaging Optics Assembly and Wide Field Instrument 19

Optical Design and Predicted Performance of the WFIRST Phase...

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19th Conference on current developments in Lens design and optical engineering

作者： Pasquale, Bert A. Casey, Thomas Marx, Catherine Gao, Guangjun Armani, Nerses Content, David Hagopian, John Jurling, Alden Jackson, Clifton Liu, Alice Whipple, Art Murray, Jacob NASA Goddard Space Flight Ctr Greenbelt MD 20771 USA AS&D Inc 7000 Muirkirk Meadows Dr Beltsville MD 20705 USA Sigma Space Inc 4600 Forbes Blvd Lanham MD 20706 USA SGT Inc 7701 Greenbelt Rd Greenbelt MD 20770 USA ATA Aerosp Inc Greenbelt MD 20770 USA Conceptual Analyt Inc Glenn Dale MD 20769 USA Rose Hulman Inst Technol Terre Haute IN 47803 USA

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

Now in Phase-B, the architecture of the Wide-Field Infra-Red Survey Telescope (WFIRST) payload has matured since 2013 to accommodate various opto-mechanical constraints. Based on a 2.4-meter aperture Forward optical Assembly (FOA), the Imaging Optics Assembly (IOA) provides corrected optical fields to each on-board instrument. Using a Three Mirror Anastigmat (TMA) optical design, the Wide-Field Channel (WFC) provides similar to 1/3-square degree of instantaneous field coverage at 0.11 arcsecond pixel scale. The WFC as-built predictive analysis anticipates near diffraction-limited imaging over a focal plane of 300.8 million pixels, operating in seven panchromatic bands between 0.48 -2.0 mu m, or a 1-octive multi-spectral imaging mode from similar to 0.95-1.93 mu m. The IOA provides the Coronagraph Instrument (CGI) a collimated beam with very specific wavefront constraints. We present configuration changes since 2013 that improved interfaces, improved testability, and reduced technical risk. We provide an overview of our Integrated Modeling results, performed at an unprecedented level for a phase-A study, to illustrate performance margins with respect to static wavefront error, jitter, and thermal drift.

关键词： Space Instrumentation Astronomical Optics Imaging Systems Telescopes Dark Energy Spectroscopy Systems engineering Integrated Modeling

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System matrix generation for 3D tomographic reconstructions using an optical design software 19

System matrix generation for 3D tomographic reconstructions ...

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19th Conference on current developments in Lens design and optical engineering

作者： Rilling, Madison Bourrassaa, Francois Archambault, Louis Thibault, Simon Univ Laval Dept Phys Genie Phys & Opt Quebec City PQ Canada Univ Laval Ctr Hosp Univ CHU Quebec Ctr Rech Quebec City PQ Canada Ctr Opt Photon & Laser Quebec City PQ Canada

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

3D imaging of solid targets using plenoptic cameras has been extensively explored and optimized over the years. Unfortunately, these imaging techniques, typically making use of triangulation methods and contrast recognition for depth estimation, lose their validity when imaging translucent media. For these cases, tomographic reconstruction has been shown to be a promising avenue for recovering the 3D shape of a translucent volume. Apart from the tomographic reconstruction algorithm itself, the accuracy of a reconstructed solution depends on the set of measured projections and on the system matrix. A proper determination of the system matrix is key as its elements describe the weighted contribution of a voxel in object space to one in image space;however, computing the matrix elements can consist of an arduous task as it requires a priori knowledge of the imaging system and precise modeling of the physical properties of the acquisition process. In this work, we present how an optical design software can be used to generate such system matrices. Compared with approximation methods involving paraxial ray tracing, the proposed method offers the main advantage of real ray tracing, in which the computed weighted contributions intrinsically account for optical aberrations in the imaging system. Physical properties of light propagation within the translucent medium can also be taken into account when using non-sequential modes. Using a ray tracing software thus offers great flexibility in designing plenoptic imaging systems used with 3D tomographic reconstruction techniques.

关键词： optical design software 3D tomographic reconstruction ray tracing ray tracing plenoptic camera translucent media 3D emission computed tomography

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Optimizing trefoil phase plates design for color wavefront coding 19

Optimizing trefoil phase plates design for color wavefront c...

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19th Conference on current developments in Lens design and optical engineering

作者： Olvera-Angeles, Miguel Padilla-Vivanco, Alfonso Ortega, Karina Sasian, Jose Schwiegerling, Jim Arines, Justo Acosta, Eva Univ Politecn Tulancingo Hidalgo 43629 Mexico Univ Arizona Coll Opt Sci Tucson AZ 85721 USA Univ Santiago de Compostela Fac Fis Santiago De Compostela 15782 Spain

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

Wavefront coding refers to the use of a phase modulating element in conjunction with deconvolution to extend the depth of focus of an imaging system. The coding element is an asymmetrical phase plate shape, for most applications in the form of a trefoil or a cubic polynomial. Phase plates with trefoil shape generate not only the desired amount of trefoil aberration but also spherical aberration. It has been recently shown that a wavefront coding based optical system shows high tolerance to spherical aberration for monochromatic images;however, the depth of focus is considerably shortened for color images. In this work, we will show how to modify the shape of a phase plate in order to optimize its performance for color imaging. The design parameters of the phase plate are obtained by minimizing a merit function by means of genetic algorithms developed for this purpose. The evaluation of the optical characteristics of the phase plates for a feedback with the optimization algorithm is obtained by Zemax. Results will be illustrated by numerical simulations of color images.

关键词： Wavefront coding spherical aberration color imaging optimization genetic algorithms

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design of coded structured light based on square-shaped primitives 19

Design of coded structured light based on square-shaped prim...

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19th Conference on current developments in Lens design and optical engineering

作者： Lau, Chi-Chung Sun, Ching-Chern Yang, Tsung-Hsun Yu, Yeh-Wei Chou, Si-Min Ind Technol Res Inst Green Energy & Environm Res Labs Bldg 24195Sec 4Chung Hsin Rd Hsinchu 31057 Taiwan Natl Cent Univ Dept Opt & Photon Kwoh Ting Opt & Photon Bldg300 Jhongda Rd Taoyuan 32001 Taiwan

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

This paper presents a new pattern design for encoding structured light for scanning 3D surface and the decoding process. The basic unit of the pattern is a code-block that contains one central label and eight square-shaped primitives that provide two functions: code-block indexing and point-positions for triangulating. The square-shaped primitive has one notch in a different position to represent 8 digit numbers, which are easily to convert label to number for indexing code-block. One primitive also contributes five point-positions, centroid and four extreme, for triangulating and estimating 3D information. The design of code-block has eight 8-bit numbers allowing a higher error-tolerant and providing better resolution in 3D reconstruction. Experiment shows that the proposed pattern is suitable for indoor mapping and large scene scanning.

关键词： coded structured light primitives 3-D data acquisition computer vision

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Proceedings of SPIE - The International Society for optical engineering

Proceedings of SPIE - The International Society for Optical ...

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19th Conference on current developments in Lens design and optical engineering 2018

ISBN: (纸本)9781510620612

The proceedings contain 33 papers. The topics discussed include: correction of wavefront aberrations in focal and afocal TMAs;a thermal glass for infrared optics;caustic surfaces produced by a plane wavefront refracted through cemented doublet lenses;holographic progressive lenses;using effective medium theories to design tailored nanocomposite materials for optical systems;toward semantic loop closure in simultaneous localization and mapping systems;optic design and manufacturing issues of a high numerical broad band IR solid immersion microscope objective;optical design and predicted performance of the WFIRST phase-B imaging optics assembly and wide field instrument;and novel designs for minimizing diffraction effects of large segmented mirror telescopes.

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The vector-apodizing phase plate coronagraph: design, current performance, and future development

arXiv

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arXiv 2021年

作者： Doelman, David S. Snik, F. Por, E.H. Bos, S.P. Otten, G.P.P.L. Kenworthy, M. Haffert, S.Y. Wilby, M. Bohn, A.J. Sutlieff, B.J. Miller, K. Ouellet, M. de Boer, J. Keller, C.U. Escuti, M.J. Shi, S. Warriner, N.Z. Hornburg, K.J. Birkby, J.L. Males, J. Morzinski, K.M. Close, L.M. Codona, J. Long, J. Schatz, L. Lumbres, J. Rodack, A. van Gorkom, K. Hedglen, A. Guyon, O. Lozi, J. Groff, T. Chilcote, J. Jovanovic, N. Thibault, S. de Jonge, C. Allain, G. Vallée, C. Patel, D. Côté, O. Marois, C. Hinz, P. Stone, J. Skemer, A. Briesemeister, Z. Boehle, A. Glauser, A.M. Taylor, W. Baudoz, P. Huby, E. Absil, O. Carlomagno, B. Delacroix, C. Leiden Observatory Leiden University P.O. Box 9513 Leiden2300 RA Netherlands Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 United States Aix Marseille Univ CNRS CNES LAM Marseille France Steward Observatory University of Arizona 933 North Cherry Avenue TucsonAZ85721 United States Anton Pannekoek Institute for Astronomy University of Amsterdam Science Park 904 Amsterdam1098 XH Netherlands COPL Département de physique génie physique et optique Université Laval 2375 rue de la Terrasse QuebecG1V 0A6 Canada Department of Electrical and Computer Engineering North Carolina State University RaleighNC27695 United States Department of Physics University of Oxford Denys Wilkinson Building Keble Road OxfordOX1 3RH United Kingdom Harvard & Smithsonian | Center for Astrophysics 60 Garden St CambridgeMA02138 United States College of Optical Sciences University of Arizona 1630 E University Blvd TucsonAZ85719 United States 650 North A‘ohōkū Place HiloHI96720 United States Astrobiology Center of NINS 2-21-1 Osawa Mitaka Tokyo181-8588 Japan NASA-Goddard Space Flight Center GreenbeltMD United States Department of Physics University of Notre Dame South BendIN United States Department of Astronomy California Institute of Technology 1200 East California Blvd. PasadenaCA91125 United States SRON Netherlands Institute for Space Research Landleven 12 Groningen9747AD Netherlands National Research Council of Canada Herzberg 5071 West Saanich Road VictoriaBCV9E 2E7 Canada Department of Physics and Astronomy University of Victoria 3800 Finnerty Road VictoriaBCV8P 5C2 Canada Department of Astronomy and Astrophysics University of California Santa Cruz 1156 High Street Santa CruzCA95064 United States Naval Research Laboratory Remote Sensing Division 4555 Overlook Ave. SW WashingtonDC20375 United States Institute for Particle Physics and Astrophysics ETH Zurich Wolfgang-Paulistr. 27 Zurich8093 Switzerland UK

Over the last decade, the vector-apodizing phase plate (vAPP) coronagraph has been developed from concept to on-sky application in many high-contrast imaging systems on 8-m class telescopes. The vAPP is an geometric-phase patterned coronagraph that is inherently broadband, and its manufacturing is enabled only by direct-write technology for liquid-crystal patterns. The vAPP generates two coronagraphic PSFs that cancel starlight on opposite sides of the point spread function (PSF) and have opposite circular polarization states. The efficiency, that is the amount of light in these PSFs, depends on the retardance offset from half-wave of the liquid-crystal retarder. Using different liquid-crystal recipes to tune the retardance, different vAPPs operate with high efficiencies (> 96%) in the visible and thermal infrared (0.55 µm to 5 µm). Since 2015, seven vAPPs have been installed in a total of six different instruments, including Magellan/MagAO, Magellan/MagAO-X, Subaru/SCExAO, and LBT/LMIRcam. Using two integral field spectrographs installed on the latter two instruments, these vAPPs can provide low-resolution spectra (R∼30) between 1 μm and 5 μm. We review the design process, development, commissioning, on-sky performance, and first scientific results of all commissioned vAPPs. We report on the lessons learned and conclude with perspectives for future developments and applications. © 2021, CC BY.

关键词： optical transfer function

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Field-of-view enhancement for commercially available active imaging camera using time-of-flight technology 19

Field-of-view enhancement for commercially available active ...

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19th Conference on current developments in Lens design and optical engineering

作者： Poulin-Girard, Anne-Sophie Smith, Michael Gagnon, Mathieu Legault, Marc-Antoine Thibault, Simon Univ Laval Ctr Opt Photon & Lasers 2375 Rue Terrasse Quebec City PQ G1V 0A6 Canada Innovat Vehicle Inst 25 Boul Maisonneuve St Jerome PQ J5L 0A1 Canada

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

Active imaging techniques have been, and will remain relevant as an integral part of the sensor network needed in mobile robotics navigation, most commonly with the use of LiDARs. For close range applications, time-of-flight (TOF) cameras are an alternative to more expensive LiDARs. The Kinect v2 (Kinect for XboxOne) has been used frequently as a range imaging camera in machine vision research because of its low cost and good performance. For mobile robotics applications moving at low speed, a larger field of view than the original (70 degrees X 60 degrees) would be desirable to increase awareness of the surroundings, and also detect other moving objects in the trajectory. Our main goal is therefore to increase the Kinect v2 field of view while keeping its main feature of depth measurements. A simple but effective solution consists in using a conversion lens to increase the ray collection angle before the rays enter the IR camera. Depth measurements remain possible from each pixel using TOF with the Kinect v2 modulated signal, provided the field of illumination matches the field of view. A trade-off has to be made between accuracy of depth measurement, optical performance and field of view/illumination enhancement. Therefore, we modified a Kinect v2 to characterize its optical performances and evaluate its relevancy for applications requiring accurate knowledge of the 3D surroundings. A field of view improvement of the Kinect v2 and other similar TOF cameras could offer an alternative at minimal cost for depth measurements in machine vision, specifically in mobile robotics research where object detection and mapping tasks are frequently carried out.

关键词： Active imaging optical system mobile robotics depth camera range imaging time of flight wide angle machine vision

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Optic design and manufacturing issues of a high numerical broad band IR solid immersion microscope objective 19

Optic design and manufacturing issues of a high numerical br...

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19th Conference on current developments in Lens design and optical engineering

作者： Sure, Thomas Sabbineni, Prasad Ramsay, Euan Univ Appl Sci Mittelhessen Giessen Germany Thermo Fisher Sci 3400 West Warren Ave Fremont CA USA

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

Over the last two decades solid immersion objectives have been developed for various applications, offering the opportunity to achieve a higher resolution than is possible for conventional air objective lenses. For semiconductor applications hemispherical solid immersion lenses (SILs), incorporating tips fabricated in semiconductor materials with a high refractive index (up to n = 3:5 for silicon, for example) are commonly used. With such high refractive index materials it is possible to design an objective with a numerical aperture of NA = 3:2. An apochromatic color correction is mandatory if a broad spectral range from lambda = 1200 nm to lambda = 2000 nm is required. It is well known that glasses with anomalous partial dispersion must be used to realize apochromatic color correction. It will be shown that the anomalous partial dispersions of some glasses in the IR range differ from the known behavior in the visible region. Therefore, glass selection plays a significant role for the design of a high NA broadband IR objective and will be discussed. Monte Carlo tolerance analysis shows that even with state of the art manufacturing capabilities the tolerance induced aberrations of an objective with NA = 3:2 will lead to a dramatic loss of image performance, indicated by a significant drop in the Strehl-ratio. This becomes even worse when the interface of the exchangeable hemispherical SIL tip with the main objective is considered. With the aim to manufacture such objectives within a stable production process it makes no sense to overload the requirements regarding the NA. Therefore, due to manufacturing issues the numerical aperture of this objective has been restricted to NA = 2:9. Wave front measurements of the manufactured objectives shows Strehl-ratios of SR > 97 % which guarantees a diffraction limited resolution.

关键词： Solid immersion lens Optic design High NA optics IR optics Glass selection Manufacturing tolerances

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Comparison between the Arclight Ophthalmoscope and a Standard handheld Direct Ophthalmoscope: a Clinical study 19

Comparison between the Arclight Ophthalmoscope and a Standar...

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19th Conference on current developments in Lens design and optical engineering

作者： Parthasarathy, Mohana Kuppuswamy Faruq, Ibrahim Arthurs, Eugene Lakshminarayanan, Vasudevan Univ Waterloo Sch Optometry & Vis Sci Waterloo ON Canada Costco Opt Waterloo ON Canada SPIE Bellingham WA USA Univ Waterloo Dept Phys Waterloo ON Canada Univ Waterloo Dept ECE Waterloo ON Canada Univ Waterloo Dept Syst Design Engn Waterloo ON Canada

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

The direct ophthalmoscope, a handheld device gives a highly magnified image of the retina. However, the sustainability of power source and cost are a limitation considering the usage demand. We compared a low-cost solar-powered Arclight ophthalmoscope with a standard ophthalmoscope Heine K180 in terms of ease of examination, usage, field of view, color rendition and patient comfort. Two clinically trained optometrists examined 28 patients and graded the ease of retinal examination, ease of use and assessed cup-disc ratio, which is an important diagnostic parameter for glaucoma, patient comfort and length of examination (scale 1-4). The examiners had good agreement for all assessments. Of a total of 78 examinations, only 8(10.3%) did not result in cup-disc ratio measurement in the undilated pupil condition using both devices. Ease of use was scored higher for Arclight than Heine but this was not statistically significant. In conditions like large discs, the Arclight resulted in easier examinations due to its larger field of view. Color rendition was better with the Heine device. In undilated pupils, the patients often reported that there was significant glare with Heine, however, post-dilation, they reported more glare with Arclight compared to Heine (73% versus 55%). The performance of Arclight was comparable to that of Heine and can be considered a low-cost alternative to the standard direct ophthalmoscope especially in large-scale patient examinations in developing countries where cost might be a factor.

关键词： Direct Ophthalmoscope Retina ophthalmology cup to disc ratio Arclight ophthalmoscope Heine ophthalmoscope solar powered ophthalmoscope

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