Night Vision Devices Research Articles

Response of a lead-free borosilicate-glass microchannel plate to 14-MeV neutrons and γ-rays

In microchannel plate applications, such as in space telescopes, night-vision devices, or time-of-flight particle detection, reducing the sensitivity to signals from background sources, such as γ-rays, is beneficial for the system design and performance. The response of a single-stage lead-free borosilicate-glass microchannel plate to 14-MeV neutrons and γ-rays produced via (n, γ) reactions in surrounding structures was investigated at OMEGA. The average efficiency values for secondary electron production were found to be (5.1 ± 0.7) × 10−3 for 14-MeV neutrons and (4.9 ± 1.1) × 10−3 for ⟨1.5⟩-MeV γ-rays.

NEW METHODS FOR STUDYING THE ACTIVITY OF SEMIAQUATIC MAMMALS

A new method for studying the activity of semiaquatic mammals using digital portable voice recorders has been developed. Previously, actographs and night-vision devices were used to study semiaquatic mammals near their burrows. This method allows the mammal activity registration directly in the burrows. The use of voice recorders makes it possible to accurately determine whether the burrow system is inhabited or non-inhabited. In addition, it has become possible to identify the day-night time intervals during which the animals are the most or least active. The new method was tested on the Russian desman (Desmana moschata). Therefore, to identify the burrows in which the recorders were to be installed, the burrows were probed. A probe is a pole pointed at one end with a T-shaped handle at the other end. The researcher's task is to detect the entrance to the burrow, usually under water. And then the direction of the underground passage is determined by means of the probe. For this purpose, the ground is pierced to detect the hollows in the burrow with the probe starting from the burrow entrance (the probe falls through unevenly). At a distance of 2–3 meters from the burrow, in some cases largely depending on the burrow length, the ground is dug up above the burrow in the form of a small well, 10–15 cm in diameter. A digital voice recorder was placed vertically in this well, so that the microphone was directed down towards the burrow. Desman noises can be characterized as short series formed as a sequence of contiguous short peaks of 15–25 seconds with 5 second interruptions formed by regular waves of breathing and its movement noises. Desman noises differ by mean amplitude and duration on oscillograms. As a rule, the noise audibility ranges from 1 to 3 minutes.

Near-earth space optical observation payload cabin design

Atmospheric clouds and fogs can weaken the intensity of the visible light by absorption, refraction, scattering and reflection, which greatly affect the detection effect of ground-based optical observation instruments. To solve this problem, near-earth space-based optical observation platform is a good choice which is more flexible and cheaper than satellite-based optical observation platform in space. This paper describes the whole design of the near-earth space optical observation payload cabin including electronics design and mechanical design. The payload capacity is 100Kg and supports 4x RS422, 4x CameraLink, 4x analog video and 4x LAN, it can provide energy supply, mode control, temperature control, data storage and data transmission services for the experiment loads. The payload cabin developed in this paper has participated in the actual experiment and reached to an altitude of 20 Km, and then safely landed after staying for 2 h in the stratosphere. The scientific load obtained real and reliable experimental data and the optical loads also obtained precious data and images during the experiment. The payload cabin developed in this experiment will take ultraviolet spectrograph, low-light level night vision device, planetary telescope and multi-band airglow imager to an altitude above 20Km for experiment in the near future.

РАЗРАБОТКА СТРУКТУРНОЙ СХЕМЫ ПАССИВНОГО ПРИБОРА НОЧНОГО ВИДЕНИЯ ДЛЯ ПОДВИЖНОГО РАЗВЕДЫВАТЕЛЬНОГО ПУНКТА

The article discusses this engineering of a structural scheme on the basis of a modern optical-electronic base of the passive night vision device for a mobile reconnaissance unit. The characteristics of functional blocks and structural scheme of the device are considered. The сonjectured structural scheme of the device instead of the product type 1PN29 is given.

Mixed Lead–Tin Halide Perovskites for Efficient and Wavelength‐Tunable Near‐Infrared Light‐Emitting Diodes

Near-infrared (NIR) light-emitting diodes (LEDs), with emission wavelengths between 800 and 950 nm, are useful for various applications, e.g., night-vision devices, optical communication, and medical treatments. Yet, devices using thin film materials like organic semiconductors and lead based colloidal quantum dots face certain fundamental challenges that limit the improvement of external quantum efficiency (EQE), making the search of alternative NIR emitters important for the community. In this work, efficient NIR LEDs with tunable emission from 850 to 950 nm, using lead-tin (Pb-Sn) halide perovskite as emitters are demonstrated. The best performing device exhibits an EQE of 5.0% with a peak emission wavelength of 917 nm, a turn-on voltage of 1.65 V, and a radiance of 2.7 W Sr-1 m-2 when driven at 4.5 V. The emission spectra of mixed Pb-Sn perovskites are tuned either by changing the Pb:Sn ratio or by incorporating bromide, and notably exhibit no phase separation during device operation. The work demonstrates that mixed Pb-Sn perovskites are promising next generation NIR emitters.

Polar bear hair inspires stealth fabric

Hide your lettuce and lock up the carrots: Stealth rabbits are on the prowl. Researchers have woven a cloak that makes a bunny almost invisible to infrared cameras, thanks to fibers that mimic the structure of polar bear hairs (Adv. Mater. 2018, DOI: 10.1002/adma.201706807). The hairs of a polar bear have hollow cores, which reflect back IR emissions from the animal’s body. By trapping those emissions, this structure helps prevent heat loss and keeps the bears warm in their Arctic environments. But the hairs have an added advantage: They can conceal the bears from thermal imaging cameras used in many night-vision devices. Textiles that can mimic polar bear hair’s IR-reflecting abilities might be useful in stealth applications, such as concealing soldiers. Previous attempts to make synthetic versions of the hairs have produced fibers that are too weak to be practically useful. A team from Zhejiang University has now used a

Чувствительность матриц ПЗС с электронным умножением

The sensitivity and basic electrical characteristics of the developed direct illumination matrices with charge-coupled devices and electronic multiplication were investigated at room temperatures and low illumination. Photomatrices of 576´288 and 640´512 format were designed using frame transfer architecture and 1.5-µm design rules with photosensitive cell sizes of 20´30 and 16´16 µm, respectively, and manufactured using n-channel technology with buried channel, four levels of polysilicon electrodes and two levels of metallization. To analyze the possibilities of the developed EMCCD matrices used in monitoring systems at low-light conditions, an experimental assessment of the matrices sensitivity was carried out. The assessment was based on a comparison of the luxmeter readings and Johnson's criteria using the standard 1951 USAF resolution target test table for the minimum size of line pairs distinguished by the observer (one pair consists of a dark and a light lines). The characteristics obtained with illumination of 5∙10–4 lux (glow of the starry sky with light clouds) and 10–2 lux (glow of the starry sky and the quarter of the Moon) corresponds to the parameters of generation 2+ electron-optical converters, which implies the possibility to use such matrices in night vision devices. At Åv ≈ 5∙10–4 lux, the camera with the developed EMCCD matrices will detect a human figure at the distance of about 200 m. With illumination of 10–2 lux at this distance a human figure can be identified.

Performance of dismounted soldiers during waypoint navigation in darkness using GNSS-supported digital map or paper map

Navigating in unknown terrain on foot in darkness is in many aspects challenging. This can be facilitated by support of GNSS positioning, digital maps and night vision devices. To investigate the advantages of technical support and its use in darkness, an experimental study was performed. In this study, dismounted soldiers equipped with a night vision device navigated in darkness with either a GPS device (with digital map) or a paper map and compass. The results showed that the distance traversed was shorter and that the soldiers needed significantly less time to navigate when supported by the GPS device compared to using a paper map and compass. The main reason for this difference was that the proportion of time in motion was significantly larger when the GPS device was used. Also, subjective ratings showed significantly higher preference for the GPS device than for the paper map and compass.

Apparent distance theory revision for low-light-level night vision system based on noise factor

This paper introduces basic concept of the detection range of a low-light-level (LLL) imaging system, and on the basis of previous derivation of visual distance detection equation for the LLL imaging system, the influence of noise factor on visual distance of LLL night vision system is discussed emphatically. Image intensifier is the most important part of LLL night vision device and SNR is one of the important parameters of micro-light image intensifier, whose value determines the detection distance and image sharpness of LLL imaging system in low-light conditions. In this paper, using system noise factor relation, by modifying the noise factor, a more practical and perfect horizon detecting equation is established, and the horizon estimation is carried out with the experiment, and the practicability of the corrected Horizon formula is verified. It has a certain guiding significance for improvement of the LLL imaging system and the development of night vision technology.

Cetacean sightings and acoustic detections during a seismic survey off Nicaragua and Costa Rica, November-December 2004

Although the wider Eastern Tropical Pacific has been systematically surveyed during summer/fall, relatively little effort has focused on shelf and slope waters of Nicaragua and Costa Rica. Such data are useful for establishing baseline information and assessing potential changes in cetacean occurrence and distribution relative to natural (e.g., El Niño-Southern Oscillation, climate change) and anthropogenic factors. A visual-acoustic survey for cetaceans occurred as part of a monitoring and mitigation program during an academic geophysical seismic study off Nicaragua and Costa Rica, during November-December 2004. Approximately 2 067 cetaceans representing at least seven species were seen in 75 groups during 373 h (3 416 km) of daytime observations from the seismic research vessel (R/V) Maurice Ewing. The humpback whale (Megaptera novaeangliae) and the pantropical spotted dolphin (Stenella attenuata) were the most frequently sighted species (30 % of all groups sighted); both were seen in shelf waters < 100 m deep and in slope waters. The bottlenose dolphin (Tursiops truncatus; 10 % of sightings) was the third most frequently sighted species and was only seen in water > 100 m deep. In addition, sightings were made of spinner dolphins (S. longirostris), short-beaked common dolphins (Delphinus delphis), Risso’s dolphins (Grampus griseus), short-finned pilot whales (Globicephala macrorhynchus), and unidentified dolphins and whales. Unconfirmed sightings of a minke whale (Balaenoptera acutorostrata) and a pod of false killer whales (Pseudorca crassidens) were also recorded. An additional six groups of dolphins (50 % confirmed to species, all pantropical spotted dolphins) were made during 187 h (1 549 km) of observation effort during darkness, two of which were detected within 30 m of the vessel bow using a night vision device. A total of 217 cetacean detections occurred during 633 h of passive acoustic monitoring. A small concentration of 12 humpback whales was seen in eight groups, and two humpbacks were recorded singing in the Gulf of Fonseca on 9 December 2004. To our knowledge, such concentrations of humpback whales, particularly singing humpbacks, have not been previously reported in this specific area. In addition, a humpback mother-calf pair, likely from the Northern Hemisphere population, was seen off Northern Costa Rica on 25 November 2004. Although cetacean sighting rates were significantly different during seismic and non-seismic periods even when corrected for differential detection probability related to sea conditions, our survey results do provide information to address previous data gaps on cetacean occurrence in shelf and slope waters off the Pacific coast of Central America during late fall.

A treatise to vision enhancement and color fusion techniques in night vision devices

In this article a vast literary and ample historic review has been examined to provide in detail introduction, knowledge and comparison of night vision imaging techniques. It unveils night vision enhancement methods described in the recent times such as contrast enhancement; color transfer based clustering, fast color contrast enhancement and pseudo-color fusion algorithm for self-adaptive enhancement system along many others. Furthermore, the scientific and mathematical details are elaborated along with the mechanisms used image fusion techniques, color mapping, histogram matching and statistical evaluation. Conclusively, the channel based color fusion technique stood out through statistical and perceptual analysis.

High Purity Germanium, a Review on Principle Theories and Technical Production Methodologies

Since the early 1950’s the use of Germanium has been continuously growing as new applications are being developed. Its first commercial usage as the main material, from which the semiconductors were made, was later replaced by Silicon. The applications were then shifted to a key component in fiber optics, infrared night vision devices and space solar cells, as well as a polymerization catalyst for polyethylene terephthalate (PET). With the advance development in new technologies, the attentions have been brought back to Germanium due to its excellent semiconductor properties. New applications on the field of high efficiency solar cells, SiGe based chips, LED technologies, etc., are being developed and show a great potential. According to DERA (Deutsche Rohstoffagentur/German Mineral Resources Agency), the demand for Ge will grow considerably by 2030, pushed mostly by the increase in the fiber optics market and advanced materials sector [1]. Therefore, this paper focuses on an overview of the production chain of Germanium, especially from its concentrate up to the single crystal growth of its valuable ultra-pure metallic form to be used in high technological applications.

Decontamination of a Diving Suit

Abstract When working in chemical or biological environments, contamination is an extremely dangerous issue for the rescue services of the fire department, police and the army. Modern protective overalls worn by fire fighters or dry “Viking” diving suits made from neoprene or nylon covered with polyurethane, have been proven to ensure sufficient protection. However, once the contaminated area is left, there is a need to perform decontamination of the external and internal surfaces of the protective overalls; in order to ensure the clothing continues to offer a high level of comfort and to retain the durability of said protective clothing, it is of course also necessary to perform a drying procedure. Moreover, there is a risk of a transfer of pathogenic micro-organisms between persons utilising the same protective clothes, particularly in the case of expensive specialist suits. Micro-organisms which may potentially spread through clothing include intestinal bacteria, such as: Salmonella, Shigella, Campylobacter, E. coli (including E. coli O157), C. difficile, viruses inducing infections of the upper respiratory tract and alimentary tract (noraviruses, rotaviruses, adeno and astroviruses). The risk of infection also involves the presence of the flu viruses, herpesviruses and pathogens transferred through skin, such as S. aureus (including MRSA), yeast-like fungi (Candida albicans), fungal strains inducing Tinea pedis and Tinea corporis [1]. Pathogenic micro-organisms can easily transfer from fabric surface onto the body of a person wearing protective clothing. From the numerous available techniques of decontamination of surfaces, equipment and protective clothing we propose to use for this purpose gaseous hydrogen peroxide (H2O2), a very effective biocidal agent. In field conditions, typical for the activities of rescue crews of the fire department, police and army we assume utilisation of a portable decontamination chamber enabling performance of a complete decontamination process. The process lasting approximately 3 hours encompasses 3 phases: • Drying phase; • Decontamination with gaseous hydrogen peroxide; • Catalytic combustion phase of hydrogen peroxide residues to a level safe for the environment. The integrated humidity and H2O2 level sensors ensure automatic control of the entire process and the unique distribution system of gaseous H2O2 secures full accessibility of the biocidal agent to the external surface of protective clothing as well as its interior. Moreover, the container allows for the conduction of the complete decontamination of the rescue equipment, night vision devices, binoculars, field telephones, radio stations, etc. Upon decontamination cycle completion, we obtain a completely dried suit which can be safely used by another crew member.

Advantages of solid-state photodetectors for a spectral interval of 1.4–1.7 μm in night-vision devices

Characteristics of external conditions are studied in spectral intervals of 0.4–0.9 and 1.4–1.7 μm. The advantages of photodetector arrays that are sensitive in a spectral interval of 1.4–1.7 μm are demonstrated for applications in night-vision devices.

Optical and electrical characterizations of a single step ion beam milling mesa devices of chloride passivated PbS colloidal quantum dots based film

Colloidal Quantum Dots (CQDs) are of increasing interest, thanks to their quantum size effect that gives rise to their usage in various applications, such as biological tagging, solar cells and as the sensitizing layer of night vision devices. Here, we analyze the optical absorbance of chloride passivated PbS CQDs as well as revealing a correlation between their photoluminescence and sizes distribution, using theoretical models and experimental results from the literature. Next, we calculate the CQDs resistivity as a film. Although resistivity can be calculated from sheet resistance measurement using four point probes, such measurement is usually carried-out on the layer’s surface that in most cases has dangling bonds and surface states, which might affect the charges flow and modify the resistivity. Therefore; our approach, which was applied in this work, is to extract the actual resistivity from measurements that are performed along the film’s thickness (z-direction). For this intent, we fabricated gold capped PbS mesas devices using a single step Ion Beam Milling (IBM) process where we milled the gold and the PbS film continually, and then measured the vertical resistance. Knowing the mesas’ dimensions, we calculate the resistivity. To the best of our knowledge, no previous work has extracted, vertically, the resistivity of chloride passivated PbS CQDs using the above method.

Design and realization of low-light-level night-vision device detection system based on machine vision

Design and realization of low-light-level night-vision device detection system based on machine vision

Supporting Spatial Awareness with a Hand-Held GPS-Device – Effects of Degree of Support and Light Conditions

Navigating in the terrain and at the same time keeping track other groups in the unit, enemy targets, and important terrain positions is often a hard task for dismounted soldiers, especially in night-ops conditions. To investigate if performance can be improved by GPS support an experiment was performed. A platoon navigated in the terrain and squad leaders indicated direction and distance to other squads and fixed terrain positions, both in daylight and darkness. Tasks were performed with full GPS support both for navigation and indication, with limited GPS support only for navigation, and with no GPS support. Precision of indications of direction to moving positions improved with full GPS support. To improve indication of distance with GPS support, functions that provide distance information must be used. A GPS device in combination with a night vision device can be used to support these tasks in darkness.

Synthesis, growth and optical properties of an efficient nonlinear optical single crystal: L-alanine DL-malic acid

Single crystals of L-alanine DL-malic acid (LADLMA) have been grown from aqueous solution by slow-cooling technique. Powder X-ray diffraction studies reveal the structure of the crystal to be orthorhombic. The nonlinear optical conversion efficiency test was carried out for the grown crystals using the Kurtz powder technique. The third order nonlinear refractive index and the nonlinear absorption coefficient where evaluated by Z-scan measurements. As the material have a negative refractive index it could be used in the protection of optical sensors such as night vision devices.

Performance characterization of night vision equipment based on the triangle orientation discrimination methodology

Night vision equipment is crucial in order to accomplish supremacy and safety of the troops on the battlefield. Evidently, system integrators, ministry of defenses and end-users need access to reliable quantitative characterization of the expected field performance when using night vision equipment. The image intensifier tube is one of the most important engines driving the performance for night vision equipment. As a major tube manufacturer, Photonis investigates the link between its products physical design parameters and the actual end-user field performance. The developments include (1) an end-to-end performance measurement method and test facility, (2) an image-based night vision simulation, and (3) a range estimation model. The purpose is twofold: (1) being able to support the need of the integrators and end-users and (2) further systematic improvement of night vision equipment design. For the end-to-end test, Photonis and TNO cooperated in the implementation of the triangle orientation discrimination (TOD) test for night vision equipment. This test provides a clear and rigorous ranking of the products with respect to their target acquisition performance level. We present the Photonis night vision test laboratory, provide TOD results for a set of night vision devices, and show range prediction examples.

Edge-Based Multi-modal Registration and Application for Night Vision Devices

Multi-modal image sequence registration is a challenging problem that consists in aligning two image sequences of the same scene acquired with a different sensor, hence containing different characteristics. We focus in this paper on the registration of optical and infra-red image sequences acquired during the flight of a helicopter. Both cameras are located at different positions and they provide complementary informations. We propose a fast registration method based on the edge information: a new criterion is defined in order to take into account both the magnitude and the orientation of the edges of the images to register. We derive a robust technique based on a gradient ascent and combined with a reliability test in order to quickly determine the optimal transformation that matches the two image sequences. We show on real multi-modal data that our method outperforms classical registration methods, thanks to the shape information provided by the contours. Besides, results on synthetic images and real experimental conditions show that the proposed algorithm manages to find the optimal transformation in few iterations, achieving a rate of about 8 frames per second.