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A Moon-based Earth radiation observatory (MERO) could provide a longer-term continuous measurement of radiation exiting the Earth system compared to current satellite-based observatories. In order to parameterize the multi-pixel detector for such a newly-proposed MERO, which could provide high-quality spatial-temporal image, the evaluation of the entrance pupil irradiance (EPI) for each pixel is of great importance, since such EPI is an important parameter that is used to optimize MERO sensor design for the best data quality. The motivation of this work is to build an EPI estimating model for a multi-pixel MERO instrument. The rationale of this model is to sum the contributions of every location in the MERO-viewed region on the Earth’s top of atmosphere (TOA) to a MERO pixel’s EPI with considering the anisotropy in the radiance at the Earth TOA. Such anisotropy could be characterized by the TOA anisotropic factors, which can be derived from the Clouds and the Earth’s Radiant Energy System (CERES) angular distribution models (ADMs). Furthermore, we estimated the shortwave (SW) (0.2–5 µm) and longwave (LW) (5–100 µm) EPIs variation for a hypothetic MERO instrument located at the Apollo 15 landing site (selenographic coordinates: 3.628°E, 26.133°N) during a month, taking into account the effects of Earth TOA radiation changing, Moon’s orbiting around the Earth and variation of Moon’s orbit. In addition, we also evaluate the effects of MERO’s selenographic location on the EPIs by calculating the SW and LW EPIs range for any given location sensor within the MERO-deployable region (region of 80.5°W–80.5°E and 81.5°S–81.5°N on the nearside of the Moon).

Broadband field-of-view expansion using computational optics methods is presented. A pair of chirp gratings, implemented by digital micromirror devices, is placed on the optical entrance pupil plane of an optical system. The gratings perform achromatic translations of the image across the camera, and a wide image is reconstructed by a post-processing procedure. Optical design for such a system is proposed, and physical analysis shows the considerations of using these optical elements. All methods are established by simulations and experiments.

In order to test the anti-jamming ability of mid-wave infrared (MWIR) and long-wave infrared (LWIR) dual-band imaging system, a zoom mid-wave (MW) and long-wave (LW) dual-band infrared scene projector (IRSP) based on two-digital micro-mirror device (DMD) was designed by using a projection method of pixel fusion. Two illumination systems, which illuminate the two DMDs directly with Kohler telecentric beam respectively, were combined with projection system by a spatial layout way. The distances of projection entrance pupil and illumination exit pupil were also analyzed separately. MWIR and LWIR virtual scenes were generated respectively by two DMDs and fused by a dichroic beam combiner (DBC), resulting in two radiation distributions in projected image. The optical performance of each component was evaluated by ray tracing simulations. Apparent temperature and image contrast were demonstrated by imaging experiments. On the basis of test and simulation results, the aberrations of optical system were well corrected, and the quality of projected image meets test requirements.

We present the retinal plenoptoscope, a novel light field retinal imaging device designed to overcome many of the problems that limit the use of portable non-mydriatic fundus cameras, including image quality and lack of stereopsis. The design and prototype construction of this device is detailed and the ideal relationship between the eye pupil, system aperture stop and micro-image separation is investigated. A comparison of the theoretical entrance pupil size, multi-view baseline and depth resolution indicates that a higher degree of stereopsis is possible than with stereo fundus cameras. We also show that the effects of corneal backscatter on image quality can be removed through a novel method of glare identification and selective image rendering. This method is then extended to produce glare-free depth maps from densely estimated depth fields, creating representations of retinal topography from a single exposure. These methods are demonstrated on physical models and live human eyes using a prototype device based on a Lytro Illum consumer light field camera. The Retinal Plenoptoscope offers a viable, robust modality for non-mydriatic color and 3-D retinal imaging.

Purpose To develop a flexible model of the average eye that incorporates changes with age and accommodation in all optical parameters, including entrance pupil diameter, under photopic, natural, environmental conditions. Methods We collated retrospective in vivo measurements of all optical parameters, including entrance pupil diameter. Ray-tracing was used to calculate the wavefront aberrations of the eye model as a function of age, stimulus vergence and pupil diameter. These aberrations were used to calculate objective refraction using paraxial curvature matching. This was also done for several stimulus positions to calculate the accommodation response/stimulus curve. Results The model predicts a hyperopic change in distance refraction as the eye ages (+0.22 D every 10 years) between 20 and 65 years. The slope of the accommodation response/stimulus curve was 0.72 for a 25 years-old subject, with little change between 20 and 45 years. A trend to a more negative value of primary spherical aberration as the eye accommodates is predicted for all ages (20–50 years). When accommodation is relaxed, a slight increase in primary spherical aberration (0.008 μm every 10 years) between 20 and 65 years is predicted, for an age-dependent entrance pupil diameter ranging between 3.58 mm (20 years) and 3.05 mm (65 years). Results match reasonably well with studies performed in real eyes, except that spherical aberration is systematically slightly negative as compared with the practical data. Conclusions The proposed eye model is able to predict changes in objective refraction and accommodation response. It has the potential to be a useful design and testing tool for devices (e.g. intraocular lenses or contact lenses) designed to correct the eye's optical errors.

Purpose This study evaluated the feasibility of using soft contact lenses (CLs) with an opaque centre to induce absolute central scotomas that move with the eye. We examined the geometrical optics prediction that scotoma size will vary with the size of the CL's opaque centre and with ocular pupil size. We also tested the hypothesis that high environmental light levels will ensure that the ocular pupil will remain small enough, even with opaque centre CLs, to generate absolute scotomas representative of those experienced by patients with age-related macular disease. Methods Using an Octopus 900 Perimeter ( www.Haag-Streit.com), kinetic visual fields (VFs) were measured in five normally-sighted subjects using a V4e Goldmann target with CLs that had central opaque areas with diameters of 2.8, 3.0, and 3.2 mm. To control pupil size, VFs were measured with background perimeter bowl luminances of 10, 585, and 1155 cd m-2 . Subjects attempted to (i) fixate the bowl centre; and (ii) place the scotoma edge at the bowl fixation target (eccentric viewing). Results As predicted, there was a direct relationship between scotoma size and both luminance level and diameter of the opacity. Mean scotoma diameters were 0°, 17.6° and 22°, for the low, medium and high bowl luminances, respectively. Scotoma size was determined primarily by the difference between the diameters of CL opacity and the entrance pupil of the eye and the axial separation between them, and between-subject differences in pupil diameters contributed most to the between-subject variability in scotoma diameter at each light level (SD: 6.01°). Scotoma displacement during eccentric fixation confirmed the gaze-contingent characteristics of this experimental model. Conclusion It is possible to induce a gaze-contingent absolute scotoma and hence mimic central vision loss using centrally-opaque CLs provided that the CL opacity is larger than the entrance pupil of the eye. This simulation tool will, therefore, be ineffective at low environmental light levels (as shown previously) if the entrance pupil of the eye is larger than the CL opacity.

The paper deals with the problem of replacing a thin lens with a thick lens having similar third-order aberration properties as the thin lens. The equations that make possible the calculation of parameters of the thick lens, which has the same value of focal length (or transverse magnification) and one of the Seidel aberration coefficients (either Seidel aberration coefficient of spherical aberration or Seidel aberration coefficient of coma) as the thin lens for given position of the entrance pupil and object, are derived. The application of the proposed method for calculation of parameters of the thick lens is shown in examples.

In rotationally symmetric lens design, there are rule-of-thumb boundaries on field-of-view and aperture for well-known design forms that provide valuable information to the designer prior to starting a design. In the design space of unobscured three-mirror imagers, freeform optics have been shown to provide a significant benefit over conventional surface shapes, but the degree to which they improve the performance for any given combination of field-of-view, entrance pupil diameter, and F-number remains unknown. Thus, designers of these systems are not afforded any pre-design information to inform their specification decisions. Here, we designed over 200 systems to establish a first-of-its-kind roadmap of specification ranges over which an unobscured three-mirror imager using freeform surfaces can achieve diffraction-limited performance in the visible spectrum. The scalability of the findings to the infrared regions of the spectrum is also addressed.

Mirror systems make it possible to reduce device dimensions and its weight while preserving high input aperture and these systems are characterized by a number of other advantages. Their significant disadvantage is a central screening of an entrance pupil that leads to lower image quality. The paper contains description of the investigations on afocal systems formed by eccentrically cut-out mirror paraboloids (off-axis mirrors) where aperture diaphragm is displaced in the meridian plane for a defined value and a central field point is located on the optical axis. The canonic Mersenne systems are accepted as base schemas (modules) for these compositions. The paper considers two types of such systems: visible increases – Г > 0 and Г < 0. Algorithms for calculation of centered afocal systems with two and four reflections have been written in the paper and the systems are free from spherical aberration, coma, astigmatism when an input pupil is located in superimposed focal planes of all parabolic mirrors. An aberration in curvature image has been additionally corrected in three-mirror quart-parabolic scheme which is a combination of two classical telescopic Mersenne systems. The paper presents schemes and calculation results. Two-mirror schemes with non-screened input pupil have been studied in the paper and in this case all the system remains centered and an aperture diaphragm is decentered for the distance Cm which is commensurable with the diaphragm size. The paper contains description of the investigated afocal schemes with four reflections from off-axis mirror paraboloids, a prepared algorithm for calculation, the obtained formulas for making combination of canonic afocal systems formed by two mirrors. Computer simulation in software environment Opal and Zemax has been carried out in the paper. Basic description has been prepared while using two alternative methods for the class of decentered systems and aberration characteristics and schematic solutions for telescopic systems without screening with two and four reflections have been ob-tained in the paper. Two-mirror afocal systems with low-powered magnification are of some interest for practical application as accessories for registering object lenses.

Ultrahigh resolution optical imaging with large aperture is increasingly desired in space-based remote sensing and imaging system, but it is usually limited by volume and mass constraints of launch vehicle due to size and weight of the imaging system. In this paper, an annulus-sector segment primary mirror is presented, which is in high obscuration with circularity symmetrical annulus-sector around. The different structure types of the annulus-sector segment aperture are discussed, while two important parameters, width–diameter ratio and the subaperture angle are also studied. An annulus-sector optical lens is processed to verify the image performance. Experimental results show that modulation transfer function of annulus-sector segment optical system can be up to 0.23(50 lp/mm), which approaches the optical resolution of full aperture optical system with smaller size and lighter weight.

The sparse aperture provides a novel solution to the manufacturing difficulties of modern super large telescopes. Golay configurations are optimal in the sparse aperture family. Characteristics of the Golay9 multiple mirror telescope having a spherical primary mirror are investigated. The arrangement of the nine sub-mirrors is discussed after the planar Golay9 configuration is analyzed. The characteristics of the entrance pupil are derived by analyzing the sub-aperture shapes with different relative apertures and sub-mirror sizes. Formulas about the fill factor and the overlay factor are deduced. Their maximal values are presented based on the derived tangency condition. Formulas for the point spread function (PSF) and the modulation transfer function (MTF) of the Golay9 MMT are also deduced. Two Golay9 MMT have been developed by Zemax simulation. Their PSF, MTF, fill factors, and overlay factors prove that our theoretical results are consistent with the practical simulation ones.

The Millimetron space observatory with a 10-meter optical telescope is now being created in Russia; it is unparalleled in terms of the scale of scientific and technical problems to be solved in the study of objects in the Universe. The amount of information that can be received with this observatory largely depends on the chosen concept and manufacturability of technology that provide for the high quality of imaging by the telescope. Possible technical solutions and concepts that can form the basis for the creation of systems of adaptive correction of distortions of the incident radiation wavefront are considered based on the analysis of distorting factors. Versions of adaptive optics systems for the space telescope are considered and analyzed. The adaptation at the entrance pupil of the telescope is selected and substantiated, implemented with the circuit of parallel information reading by petals of the telescope integrated primary mirror. The circuit is suggested for real-time dynamic adjustment of the telescope adaptive control system by image analyzer signals. It is shown that visible radiation received from a field region shifted from the telescope optical axis with a random misalignment angle can be used as reference.

The arrival of near-eye displays has challenged the traditional methods that have been used to measure the optical properties of displays. Near-eye displays typically create virtual images and are designed for the relatively small entrance pupil of the human eye. These two attributes result in optical measurement requirements that are substantially different from traditional flat panel displays. This paper discusses the optical system requirements needed to make absolute radiometric and photometric measurements of near-eye displays. These guidelines are contrasted with the performance of current optical measurement instruments. An initial study was conducted using traditional and modified instruments and exhibited a significant variance in the results with different near-eye display designs. The study demonstrated that some traditional optical instruments can yield erroneous results when used to measure near-eye displays. Generic optical system design concepts were used to interpret the experimental results and helped to identify how current commercial designs could be modified to properly measure near-eye displays.

It is well known that imaging characteristics such as beam spot size and focal depth can be improved by applying apodization of amplitude and phase at the entrance pupil of an optical system. As an optical system for the electro-photography continuously requires highly resolved dot image and extended focal length to obtain more delicate expression with adequate production stability. Advantages from apodization technique can improve system performance and supply high degree of reliability of the optical system. However, issues on reduction in absolute optical power and on side-lobe of beam spot profile have been technical barrier for its useful implementation to imaging optics for commercial devices. Thorough this paper, theoretical feasibility of application of a pupil apodization to a laser scanning optical unit is mainly discussed in the aspects of optical power reduction and side-lobe of spot profile, as well as enhancement of optical resolution and focal depth. In addition, fundamental experimental results on beam spot profile through focal region are followed to uphold feasibility analysis.

The light field describes the radiance at a given point provided by a ray coming from a particular direction. Integrating the light field for all possible rays passing through that point gives total irradiance. For a static scene, the light field is unique. Cameras act as integrators of the light field. Previously, it was demonstrated that freeware rendering software can be used to simulate the light field entering an arbitrary camera lens. This is accomplished by placing an array of ideal pinhole cameras at the entrance pupil location and rendering. The pinhole camera images encode the ray directions for rays passing through the pinholes. The set of images from this array then describes the light field. Images for real camera lenses with different types of aberrations are then simulated directly from the light field. The advantage of this technique is that the light field only needs to be calculated once for a given scene. Calculation of the light field is computationally expensive and the practicality of implementing high resolution light field simulations on a desktop computer is limited. However, cloud-based rendering services with arrays of CPUs and GPUs are now readily available and affordable. These services enable more realistic simulations and different scenes to be rapidly created. Here, the techniques are demonstrated for different real lens aberration forms.

The Extreme Universe Space Observatory (EUSO), onboard the Japanese Experiment Module (JEM) of the International Space Station (ISS), is a project led by Japan, with contributions from the United States, Italy, Germany, France, Spain, Switzerland, Russia, South Korea and Mexico. It is devoted to the detection of ultra high-energy cosmic particles with energies E>7x1019eV, which are revealed through emission in the atmosphere of Cherenkov and fluorescence light in the near-UV region. Current experiments are all ground-based. A big enhancement would rise from space, since a bigger atmospheric target could be monitored. However, since at these high energies the signal is faint and the probability of detection is very low (~1 Km-2 century-1), the optical system must have a large aperture, wide Field of View (FoV) and be necessarily lightweight. This project is the continuation of the EUSO mission, led by ESA, stopped some years ago at the end of phase A, and JEM-EUSO is currently at the end of phase A. For both experiments, a ~2.3 m Entrance Pupil (EP) diameter and a 60° FoV were required to achieve the science goals. However, for the present configuration, the constraint of the maximum stowable dimensions of the JAXA's H-II Transfer Vehicle (HTV) unpressurized cargo area forces the instrument to have maximum transverse dimensions of 2.65 x 1.9 m2. Reflective optics, in the form of a properly designed Schmidt camera, are not yet suitable for this purpose, since these optical requirements would need a large, deployable, primary mirror. The main challenge for designing the current configuration consists in developing an unusual combination of large and lightweight refractive optics: two double-sided curved Fresnel lenses and a central curved Fresnel + diffractive lens, in UV-grade PMMA and/or CYTOP, have been considered. This paper describes the development of such a system, focusing on the possible choices of materials and overall optical design, which is responsibility of the authors. Performances of the latest configurations are also presented.

One of the most challenging open questions of modern astrophysics and particle physics is the determination of the origins and the production mechanisms of the Ultra-High Energy Cosmic Rays (UHECR), i.e. particles with energy above the Greisen–Zatsepin–Kuzmin (GZK) limit, which is about 5×1019 eV. UHECRs can be studied in two ways: either via direct detection of the secondary particles, i.e. extensive air shower (EAS), produced by UEHRCs interaction with the atmosphere, or by observing during night the track of the UV fluorescence emitted by EAS. The origin direction of the cosmic rays can be therefore determined. While ground-based observatories are already operative, different optical configurations, based mainly on the Schmidt camera layout or double Fresnel lenses concept, can be envisaged for future space-based ones. Both solutions faced in the past technological issues: transmission and resolution at large field angles for Fresnel lenses and weight of the primary mirror for the Schmidt. However, recent advances in the technology of ultra-lightweight, large and deployable active mirrors made the Schmidt camera approach feasible, becoming the preferred option. This work describes a lightweight Schmidt space telescope design for UHECRs detection conceived for a mission intended to orbit at 600 km altitude. The instrument concept is a fast, high-pixelized, large aperture and large Field-of-View (FoV) digital camera, working in the near-UV wavelength range with single photon counting capability. The telescope will record the track of an EAS with a time resolution of 2.5 μs and a spatial resolution of about 0.6 km (corresponding to ~ 4’), thus allowing the determination of energy and direction of the primary particles. The proposed design has about 50° FoV and a 4.2 m entrance pupil diameter. The mirror is 7.5 m in diameter, it is deployable and segmented to fit the diameter of the considered launcher fairing (i.e. Ariane 6.2). The Schmidt corrector plate is a lightweight annular corona. This configuration provides a polychromatic angular resolution less than 4' RMS over the whole FoV with a very fast relative aperture, i.e. F/# 0.7. Thanks to its very large pupil and large FoV, the design could be fit for a space-based observatory, thus enhancing the science achievable with respect to the presently operating ground-based counterparts, such as Telescope Array and Auger. A key advantage of this catadioptric design over the classic all refractive adopted in the past is the higher attainable global throughput. This parameter guarantees to reach and fulfil the required instrument photon collection specifications.

The Lockheed Martin Optical Payload Center of Excellence (OPCoE) collaborated with government customers and leading companies in the aerospace and optics industries to field a space imaging instrument, achieving multi-spectral, wide field, high resolution imaging capability in a compact, lightweight, all reflective architecture. The heart of the instrument is an unobscured three mirror anastigmat collimator. The afocal design consists of a physical entrance pupil accepting a collimated input, an intrinsic internal focus and pupil, and in a compact folded geometry to achieve a balance between critical sampling, radiometric sensitivity, and field of view. Light-weighted, thermally stable materials and robust coatings coupled with low stress, thermal and dynamically stable optical mounts have demonstrated diffraction limited performance during test and over predicted mission conditions. Metrology features were made a central part of the optical component design to facilitate the use of spatial analysis tools and alignment techniques for merit function prescription optimization. The optical components are mounted to a composite egg crate bench, designed to reduce structural mass while ensuring rigid alignment of the optical components. Active thermal control reduces diurnal variations to the optical alignment and ensures stable optical performance. Design innovations include a filter wheel assembly designed to minimize exported force and torque and an internal radiometric calibrator based on high reliability light emitting diodes for focal plane gain calibration. The instrument currently hosts a large format staring focal plane for wide field imaging, but the flexibility of the design can accommodate various sensor packages.

MicroCarb is a space program which uses a passive Short Wave InfraRed (SWIR) spectrometer instrument. MicroCarb will provide measurements of the atmospheric concentration of the carbon dioxide at global level with a precision sufficient in order to permit to the scientific community to improve the model of the carbon cycle by understanding the mechanisms governing the exchanges of CO2 between the sources and the sinks. The MicroCarb Instrument is currently under development at Airbus Defense & Space (ADS). Among the spectral requirements that it must meet, some concern the Instrumental Spectral Response Function (ISRF), which is a key quantity of spectrometers, needed for spectral instrument calibration and atmospheric inversion calculations. During the development of the Instrument, ADS proposed a method based on several Fourier Transforms to compute the ISRF, based on the one developed by R. Berlich for the FLORIS Instrument [1], in order to have an accurate model of its spectral performances. In this paper, we will explain the simulation method, which allows to take into account diffraction at the system entrance pupil, the spectrometer slit and the dispersion grating, and also the theoretical optical quality of the Instrument. We will describe the preliminary experiments ADS performed to validate this approach. We will then present the work done at ADS and CNES for validating and cross-checking the results of our computations, that required the use of advanced light propagation modules of CODE V. Once validated, this tool allows to accurately compute the theoretical performances of a given working point, such as the Full-Width at Half Maximum (FWHM) of the ISRF, the resolution of the spectrometer and the likeness of the ISRF to a gaussian function. It is also a powerful tool to quickly compute many ISRFs and thus carry out trade-offs on several parameters of the instrument. Finally, by including this static computation into a loop and by varying the radiance inside the slit, it is possible to obtain dynamic ISRFs of complex scenes on the ground, and thus have a complete and validated model of the spectral performances of the MicroCarb instrument.

Most conventional camera calibration algorithms assume that the imaging device has a Single Viewpoint (SVP). This is not necessarily true for special imaging device such as fisheye lenses. As a consequence, the intrinsic camera calibration result is not always reliable. In this paper, we propose a new formation model that tends to relax this assumption so that a Non-Single Viewpoint (NSVP) system is corrected to always maintain a SVP, by taking into account the variation of the Entrance Pupil (EP) using thin lens modeling. In addition, we present a calibration procedure for the image formation to estimate these EP parameters using non linear optimization procedure with bundle adjustment. From experiments, we are able to obtain slightly better re-projection error than traditional methods, and the camera parameters are better estimated. The proposed calibration procedure is simple and can easily be integrated to any other thin lens image formation model., 5 pages, 4 figures, Accepted for publication at ICIP 2019

Mitsubishi Electric, the prime contractor of Advanced Optical Satellite (ALOS-3), is developing wide swath and high resolution optical imager for the satellite. The telescope consists of off-axis four mirrors anastigmat, whose entrance pupil diameter is around φ0.55m. It realizes > 6.0 degrees field of view. The focal plane array for the imager has 12 image sensors for each band. It will provide wide swath images. The sensors are line type CCD image sensors with TDI. Panchromatic sensors have micro lens optimized for the telescope. All of them are manufactured as one optical system in domestic with optimization for ALOS-3 mission. Therefore the imager will provide state-of-the-art pushbroom images and contribute disaster monitoring, short-time mapping and various purposes.

An underwater imaging system with camera and lens behind a flat port does not behave as a standard pinhole camera with additional parameters. Indeed, whenever the entrance pupil of the lens is not in contact with the flat port, the standard photogrammetric model is not suited anymore and an extended mathematical model that considers the different media would be required. Therefore, when dealing with flat ports, the use of the classic photogrammetric formulation represents a simplification of the image formation phenomenon, clearly causing a degradation in accuracy. Furthermore, flat ports significantly change the characteristics of the enclosed imaging device and negatively affect the image quality, introducing heavy curvilinear distortions and optical aberrations. With the aim of mitigating the effect of systematic errors introduced by a combination of (i) image quality degradation, induced by the flat ports, and (ii) a non-rigorous modelling of refraction, this paper presents a stochastic model for image observations that penalises those that are more affected by aberrations and departure from the pinhole model. Experiments were carried out at sea and in pools showing that the use of the proposed stochastic model is beneficial for the final accuracy with improvements up to 50 %.

The simulation of an electro-optical sensor (EOS) of optical radiation from flame combustion and smoldering was carried out as a result of the work. The EOS is part of multi-criteria electro-optical device for monitoring emergency and pre-emergency situations in coal mines. The main analytical dependencies were formulated for the simulation of EOS. A computer model was developed. Checking the adequacy of computer simulation was completed. Simulation of the radiation flux arriving at the entrance pupil of the EOS during the smoldering of coal dust and the flame combustion of a methane-air mixture was carried out, taking into account the influence of the intermediate medium. Spectral ranges from 2.45 to 3.2 μm and 4.3 to 4.6 μm are used to control flame radiation. Spectral range from 3.5 to 4.2 μm is used to control radiation from smoldering. The element base for the assembly of EOS was selected taking into account the data on the spectral transmittance of the intermediate medium.

International audience; We present a generalized differential image motion monitor (GDIMM). It is a compact instrument dedicated to the measurement of four parameters of optical turbulence: seeing, isoplanatic angle, coherence time and wavefront coherence outer scale. The GDIMM is based on a small telescope (28 cm diameter) equipped with a three-hole mask at its entrance pupil. The instrument is fully automatic, and performs continuous monitoring of turbulence parameters at the Calern Observatory (France). This paper gives a description of the instrument, data processing and error budget. We also present statistics of three and a half years of monitoring of turbulence parameters above the Calern Observatory.

The simulation of high-speed electro-optical device for fire detection under the influence of dynamic optical interference on the entrance pupil is performed. The analysis of known approaches to providing noise immunity of the device is performed: use of selected spectral ranges of control; the use of additional channels of the device (hardware redundancy); the use of additional algorithms for signal processing channels of the device (software redundancy). Analytical dependences for modeling are formulated. The simulation of the optoelectronic device operation is performed. Calculation of the mathematical model was made using software package Matlab and the development environment RAD Studio. The characteristics of changes in spectral ratios depending on the temperature of the filament body are obtained. The spectral flux of the incandescent lamp is calculated from the dynamics of the temperature change of the incandescent body. As result of modeling, the spectral ranges of control – 1350±50, 2700±50 and 4300±50 nm were selected, and their ratios were based. Ratios of Q 2700-1350 for the spectral flow of a fire and incandescent bulbs made up 10.9 and 0.164 respectively. Ratios of Q 2700-4300 hearth and bulbs amounted to 1.34 and 4.13, respectively. The values of the ratios established in the range for Q 2700-1350 from 10.748 to 0.784 for Q 2700-4300 from 1.354 to 1.557for total flow with changes in temperature of the filament lamp. The characteristic values of the ratios changes characterizing the fire and the incandescent lamp and allowing to detect the radiation of the source against the background of optical interference are determined. Additional studies on the basis of the developed model should be carried out to more accurately identify the source of fire under the influence of dynamic optical interference.

This paper aims to compare the image quality between centration on the coaxially sighted corneal light reflex (CSCLR) and on the entrance pupil center (EPC). Myopic laser ablation was simulated on eye models, and the optical performances were compared. Centration on the EPC leads to higher wavefront aberrations and lower modulation transfer function. The two centration methods give nearly identical retinal images for angle kappa less than 5°. Because of less tissue removal, centration on the EPC is probably preferable for angle kappa less than 5°, but CSCLR centration may be preferable for angle kappa larger than 5°. The degree of tilt of the post-surgery anterior corneal surface explains the differences between the two methods.

A Moon-based Earth radiation observatory (MERO) could provide a longer-term continuous measurement of radiation exiting the Earth system compared to current satellite-based observatories. In order to parameterize the detector for such a newly-proposed MERO, the evaluation of the instrument’s entrance pupil irradiance (EPI) is of great importance. The motivation of this work is to build an EPI estimating model for a simplified single-pixel MERO instrument. The rationale of this model is to sum the contributions of every location in the MERO-viewed region on the Earth’s top of atmosphere (TOA) to the MERO sensor’s EPI, taking into account the anisotropy in the longwave radiance at the Earth TOA. Such anisotropy could be characterized by the TOA anisotropic factors, which can be derived from the Clouds and the Earth’s Radiant Energy System (CERES) angular distribution models (ADMs). As an application, we estimated the shortwave (SW) (0.3–5 µm) and longwave (LW) (5–200 µm) EPIs for a hypothetic MERO instrument located at the Apollo 15 landing site. Results show that the SW EPI varied from 0 to 0.065 W/m2, while the LW EPI ranged between 0.061 and 0.075 W/m2 from 1 to 29 October, 2017. We also utilized this model to predict the SW and LW EPIs for any given location within the MERO-deployable region (region of 80.5°W–80.5°E and 81.5°S–81.5°N on the nearside of the Moon) for the future 18.6 years from October 2017 to June 2036. Results suggest that the SW EPI will vary between 0 and 0.118 W/m2, while the LW EPI will range from 0.056 to 0.081 W/m2. Though the EPI estimating model in this study was built for a simplistic single-pixel instrument, it could eventually be extended and improved in order to estimate the EPI for a multi-pixel MERO sensor.

In order to meet the increasing demand for the diagnosis of household medical eye fundus, the design of a new fundus camera is proposed. The entire structure includes the imaging system and the lighting system. The optical imaging system, modeled on the Kepler telescope, matches the exit pupil of the human eye and the entrance pupil of the mobile phone camera. Thus, this system uses a mobile camera lens that owns more than 5 million pixels to take a picture of a clear fundus. A new type of fundus camera is designed with the field of 40°, the working distance of 30mm and the full length of 138 mm. The value of MTF outweighs 0.5 at the central field of view. The lighting system takes advantage of the Kohler illumination. The stray light of the reflection of corneal is effectively suppressed by adding an annular aperture on the optical path. The inner diameter of the annular light spot formed at the cornea was larger than 4mm, the outer diameter was less than 6mm, and the diameter of the evenly illuminated fundus area was 12mm.

The hardware-in-the-loop simulation is widely used in laser semi-active guidance weapon experiments,the authenticity of the laser signal is the key problem in the simulation system.Due to the limitations of the simulation devices, the energy distribution of the jamming laser was uneven.In order to assess the impact of the optical homogeneity,combining the application of simulation,the far-field energy distribution was measured.By optical simulation and actual test,according the receiving optical system entrance pupil,the effect on the beam quality to the simulation result was analyzed. By comparing the different working state between actual condition and hardware-in-the-loop simulation,the output of laser seeker and laser guided weapon trajectory were obtained, the influence of the uneven signal was analyzed.In conclusion it was pointed out that the difference between simulation system and actual system has little influnece on laser jamming. The research is helpful to design and evaluation of laser guided weapon simulation.

Based on the wavefront aberration theory and the coordinates transform, the free form optical induced aberration’s characteristic of optical system has been analyses in this paper. The optical wavefront error and the free form surface can be express as Fringe Zernike polynomial; the free form optical on the surface (Stop or Entrance pupil or Exit pupil) affects all the field angles equally. If the surface is not the pupil of optical system, the aberration observed is different from the free form itself because the footprint of the beam for an off-axis field point only covers part of the surface. For the Fringe Zernike surface figure on a surface not at pupil, it will transform into lower order Fringe Zernike aberration in the optical system, the relationship between different Fringe Zernike aberration and field is different, and the location zero for the lower aberration always reside at the center of the field of view.

With the development of optical machining and testing, the gap between freeform surface fabrication and design has been filled. Based on the freeform surfaces’ extraordinary feature for balancing asymmetric aberration and compressing system volume, an volume-compression optical design method for off-axis, three-mirror system is presented. Based on the guide of Nodal Aberration Theory for balancing asymmetric aberration, some optimization rules and tricks are shared during the optimization process. In the end, a highly-compact optical system with wide field of view, large entrance pupil and small F number is shown, the image quality is close to diffraction limit at Nyquist frequency.

A method to simultaneously control aberrations and the aperture of an optical system using a single phase-only spatial light modulator was investigated. The experiment was performed using a liquid-crystal-on-silicon spatial light modulator (LCoS-SLM) within an adaptive optics system used for visual testing, although the method has broader applications in adaptive optics field. The performance of the technique was characterized through the estimation of the system's modulation transfer functions (MTFs) by using a random chart method. MTFs obtained from the phase modulation-based approach were compared with those from using a real aperture (diaphragm). The areas under the MTFs for the two conditions were similar up to 98%, confirming that the low-pass filter effect associated to the size of the entrance pupil was similar for the phase-modulated pupil and the physical pupil. As an example of application, both aberrations and pupil were controlled by a single phase-only modulator to study the through-focus visual performance in real subjects. Limitations and possible enhancements of the presented method were also discussed. The presented technique reduces complexity and cost of adaptive optics systems. It opens the door to new experiments by allowing dynamic modulation of aberrations and apertures of any shape.

Wide use of underwater optics started in 1950th, since then many underwater lenses were constructed. Now the whole world is interested mostly in deep-water research, which has started about 10 years ago. Now the most of underwater lenses are specially designed. It is very important to understand a role of every optical element in underwater optical system. This helps a designer to find best solution for starting point of such a system with further automatic aberration correction. We propose to use lenses with removed forward entrance pupil for deep-water lens design. Examples of different optical schemes and explanation of their design process are presented.

The micro-nano design of a high-precision star sensor is studied. Point source transmittance (PST, the ratio of the irradiance generated by the external field source on the image surface to the irradiance at the entrance pupil) is used as the evaluation index of stray light suppression ability, the stray light suppression theory of star sensors is analyzed, and the mathematical model between stray light suppression ability and detectable magnitude is established. In view of the limited volume of micro-nano star sensors, a new design principle of combined anti-stray-light design of the baffle and optical system is proposed. The high stray light suppression of the micro-nano star sensor is realized by using the imaging optical path design of active stray light suppression and the design of a conical extinction cavity, which breaks through the technical problem of coupling system volume and stray light suppression ability. The results of the simulation and on-orbit experiments show that the star sensor based on the joint stray light technology can achieve a PST of 2 × 10 − 8 at the avoidance angle under the premise of limited optical system volume, and it has a stray light suppression ability of 6.5 magnitude stars.

We propose an optical sensor design for position measurements with sub-nanometer precision on small diffraction gratings with a wide pitch range from 400 nm to approximately 10 µm. The interferometric position detection is based on a self-reference introduced via 180°-rotational shearing. A lateral scan of the target generates a periodically varying intensity signal whose phase encodes the target position. The small size of the target (down to approximately 5 × 5 µm2) necessitates an even smaller illumination-spot size on the target for the scanning procedure. In our sensor, a spot diameter of only 2–3 µm is realized by illuminating large off-axis areas in the entrance pupil of a microscope objective with high numerical aperture (NA). A set of two complementary aperture stops ensures blocking of the specular reflection, thus allowing for a signal contrast close to one. Due to the large NA-extent of the illumination profile, the sensor is inherently sensitive for aberrations. We correct the resulting positioning error via additional beam monitoring in the pupil plane. A tolerance analysis in terms of a comprehensive simulation study shows that the sensor performance is robust against typical target and parameter variations. Furthermore, first proof-of-principle measurements validate the practical feasibility.

We study an infrared surround scan system based on a photodetector array with an entrance pupil of a small diameter with no specific requirements for achieving versatility and a high dynamic performance. A cooled midinfrared photodetector with an objective and a compensator for the tangential motion blur of an image are housed within a rotating unit. Command and data exchange are ensured using a rotating communication device mounted on a rotation axis of the moving unit. Multisegment assemblies of optical wedges are used instead of single wedges in the compensator for the tangential motion blur of the image. We demonstrate that this engineering design makes it possible to increase the signal integration time by several times compared with a basic design with single-segment wedges.

Eyewear display measurement and evaluation is based on the light rays directed from the display to the viewer and the entrance pupil of the measuring equipment. The evaluation results show that the pupil size should be smaller than the width of the light rays, found to be effective for correct evaluation and measurement of significant characteristics, such as luminance and its uniformity, in an eyewear display.