Night Vision Imaging System Research Articles

Efficient Ultra‐Broadband Phosphors for High-Power Near-infrared LED and night vision imaging system sources

Broadband near-infrared (NIR)-emitting materials have critical applications in biology, medical detection, and NIR night-vision. However, developing NIR phosphors with promising optical properties and excellent thermal stability is a great challenge for research. In this work, a novel NIR phosphor Cr3+ and Yb3+ doped CaSc2O4 (CSO) is an evolving NIR emitting phosphor with decent optical properties, boosted emission intensity, and thermal stability that makes it a promising candidate with potential applications in NIR-LED and infrared night-vision. The implications of the fundamental electronic structure of CSO, including valence-band (VB) and conduction-band (CB) orbital character, are investigated. Under blue light excitation, CSO:Cr3+ is settled with pure broadband NIR emissions (max = 920 nm, FWHM (full width at half maximum) = ∼310 nm) and good thermal stability. The occupation of two selectable lattice sites of Cr3+ in CSO is discussed in detail. Furthermore, emission enhancements of samples are done by Cr3+ and Yb3+ codoping, effectively broadening FWHM to 351 nm and reducing thermal quenching. The energy transfer (ET) routes in CSO:Cr3+,Yb3+ are investigated based on PL lifetime and comprehensive kinetic ET model, revealing that the PL enhancements by Cr3+ and Yb3+ codoping mainly originate from the ET from Cr3+ to Yb3+ emitters with more efficient and thermally stable. Finally, an InGaN-LED device encapsulated using CSO:0.01Cr3+ and CSO:0.01Cr3+,0.01 Yb3+ phosphor was fabricated. The fabricated NIR pc-LEDs are excellent candidates for NIR light sources in biological imaging and NIR night vision.

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휘도 제어가 가능한 NVIS 조명스위치의 설계와 평가

Various electronic equipments are operated in the cockpit of the aircraft, and various lamp lights and LED lights are used in each instrument panel for the stable operation of the pilot even during the night operation of the aircraft. The NVIS(Night Vision Imaging System) facilitates pilot operation by emitting a light compatible with the NVG(Night Vision Goggle) worn by the pilot. The Aviation NVIS light switches are widely used in mission equipment power panel and various panels, and most of them have been dependent on imports from advanced foreign companies. In this paper, a signal processing circuit and mechanism for an NVIS light switch capable of controlling luminance were designed and evaluated according to the MIL-STD-3009 military standard requirement.

Broadband near-infrared emission of K3ScF6:Cr3+ phosphors for night vision imaging system sources

• K 3 ScF 6 :Cr 3+ can be excited by blue light, leading to a broadband NIR emission. • K 3 ScF 6 :Cr 3+ retain 87.3% of their initial emission intensity at 150 °C. • The fabricated NIR-LED based on K 3 ScF 6 :Cr 3+ has good photoelectric efficiency. • NIR-LED based on K 3 ScF 6 :Cr 3+ can be applied in night vision imaging systems. Broadband near-infrared light (NIR) near 800 nm has broad application prospects in food detection and night vision monitoring. Compared with NIR chips, NIR phosphors have distinct advantages, including low cost, a mature synthesis process, and tunable combination. However, at present, oxide NIR phosphors have some disadvantages, such as a narrow full width at half maximum (FWHM), poor thermal stability, and low photoelectric efficiency. Herein, K 3 ScF 6 :Cr 3+ NIR phosphors with a cubic structure were synthesized using the hydrothermal method. These phosphors can be effectively excited by blue light (430 nm) and red light (630 nm), leading to a broadband Cr 3+ emission from 650 nm to 950 nm with a large FWHM of 430 nm. They also exhibit excellent thermal stability and retain 87.3% of their initial intensity at 150 °C. Under a driving current of 100 mA, their photoelectric efficiency can reach 9.315% of that of fabricated NIR light-emitting diodes (NIR-LED). An NIR-LED device based on this phosphor can thus be implemented in night vision imaging systems.

An efficient proposed framework for infrared night vision imaging system

This research presents new three proposed approaches to enhancement the visibility of the Infrared (IR) night vision images. The first proposed approach depends on Hybrid Adaptive Gamma Correction (AGC) with Histogram Matching (HGCHM). The second proposed approach stands up Merging Gamma Correction with Contrast Limited Adaptive Histogram Equalization (MGCCLAHE). The HM uses a reference visual image for converting of night vision images into daytime images. The third approach mixes the benefits of the CLAHE with the undecimated Additive Wavelet Transform (AWT) Using Homomorphic processing (CSAWUH). The quality assessments for the suggested approaches are entropy, average gradient, contrast improvement factor, Sobel edge magnitude, spectral entropy, lightness order error and the similarity of edges. Simulation results clear that the third proposed approach gives superior results to the two proposed approaches from entropy, average gradient, contrast improvement factor, Sobel edge magnitude, spectral entropy and the computation time perspectives. On the other hand, the second proposed approach takes long computation time in the implementation with respect to the two proposed approaches. The second proposed approach gives better results to the first proposed approach entropy, average gradient, contrast improvement factor, Sobel edge magnitude, and spectral entropy perspectives. The first proposed approach gives better results to the two proposed approaches from lightness order error and the similarity of edges perspectives.

Hybrid enhancement of infrared night vision imaging system

This paper presents a proposed approach for the enhancement of Infrared (IR) night vision images. This approach is based on a trilateral contrast enhancement in which the IR night vision images pass through three stages: segmentation, enhancement and sharpening. In the first stage, the IR image is divided into segments based on thresholding. The second stage, which is the heart of the enhancement approach, depends on additive wavelet transform (AWT) to decompose the image into an approximation and details. Homomorphic enhancement is performed on the detail components, while plateau histogram equalization is performed on the approximation plane. Then, the image is reconstructed and subjected to a post-processing high-pass filter. Average gradient, Sobel edge magnitude and spectral entropy are used as quality metrics for evaluation of the proposed approach. The used metrics ensure good success of this proposed approach.

Development of an Automatic Testing Platform for Aviator's Night Vision Goggle Honeycomb Defect Inspection.

Due to the direct influence of night vision equipment availability on the safety of night-time aerial reconnaissance, maintenance needs to be carried out regularly. Unfortunately, some defects are not easy to observe or are not even detectable by human eyes. As a consequence, this study proposed a novel automatic defect detection system for aviator’s night vision imaging systems AN/AVS-6(V)1 and AN/AVS-6(V)2. An auto-focusing process consisting of a sharpness calculation and a gradient-based variable step search method is applied to achieve an automatic detection system for honeycomb defects. This work also developed a test platform for sharpness measurement. It demonstrates that the honeycomb defects can be precisely recognized and the number of the defects can also be determined automatically during the inspection. Most importantly, the proposed approach significantly reduces the time consumption, as well as human assessment error during the night vision goggle inspection procedures.

InGaAs Nanomembrane/Si van der Waals Heterojunction Photodiodes with Broadband and High Photoresponsivity.

Development of broadband photodetectors is of great importance for applications in high-capacity optical communication, night vision, and biomedical imaging systems. While heterostructured photodetectors can expand light detection range, fabrication of heterostructures via epitaxial growth or wafer bonding still faces significant challenges because of problems such as lattice and thermal mismatches. Here, a transfer printing technique is used for the heterogeneous integration of InGaAs nanomembranes on silicon semiconductors and thus the formation of van der Waals heterojunction photodiodes, which can enhance the spectral response and photoresponsivity of Si photodiodes. Transfer-printed InGaAs nanomembrane/Si heterojunction photodiode exhibits a high rectification ratio (7.73 × 104 at ±3 V) and low leakage current (7.44 × 10-5 A/cm2 at -3 V) in a dark state. In particular, the photodiode shows high photoresponsivities (7.52 and 2.2 A W-1 at a reverse bias of -3 V and zero bias, respectively) in the broadband spectral range (400-1250 nm) and fast rise-fall response times (13-16 ms), demonstrating broadband and fast photodetection capabilities. The suggested III-V/Si van der Waals heterostructures can be a robust platform for the fabrication of high-performance on-chip photodetectors compatible with Si integrated optical chips.

Preparation and properties of a flexible night vision imaging system filter for avionic LED displays

A flexible near-infrared (NIR) absorption filter well suited for use as a front surface filter for night vision imaging system (NVIS) LED displays was prepared by using a transparent polymer film and acrylic resin as substrate, NIR-dyes NIR787 and NIR860 as functional additives through the solvent mixing method. In particular, this new dye-based NVIS filter material offers sharp spectral cut-off and excellent extinction in the NIR (665–930 nm) along with an appropriate transmittance in the visible spectrum (400–700 nm). The optical performance of the filter was studied, the optimal dosage of NIR787 and NIR860 was determined and the results showed there was a good linear relationship between amount of NIR-dyes and light transmittance. In addition, the filter kept good environmental stability after cyclic humid heat test, high temperature aging test, low temperature aging test and photostability test.

液晶显示器LED背光的夜视兼容特性分析

液晶显示器LED背光的夜视兼容特性分析

Experimental Flight Testing of Night Vision Imaging Systems in Military Fighter Aircraft

Abstract This paper describes the research and experimental flight test activities conducted by the Italian Air Force Official Test Centre (RSV), in collaboration with Alenia Aermacchi and Cranfield University, in order to confer night vision imaging systems (NVIS) capability to the Italian TORNADO Interdiction and Strike and Electronic Combat and Reconnaissance aircraft. The activities included design, development, test, and evaluation activities, including night vision goggle (NVG) integration, cockpit instruments, and external lighting modifications, as well as various ground test sessions and a total of 18 flight test sorties. RSV and Litton Precision Products were responsible for coordinating and conducting the installation of the internal and external lights. Particularly, an iterative process was established allowing in-site rapid correction of the major deficiencies encountered during the ground and flight test sessions. Both single-ship (day/night) and formation (night) flights were performed, with testing activities shared among the test crews involved, allowing for a redundant examination of the various test items by all participants. An innovative test matrix was developed and implemented by RSV for assessing the operational suitability and effectiveness of the various modifications implemented. Also important was the definition of test criteria for Pilot and Weapon Systems Officer workload assessment during the accomplishment of various operational tasks during NVG missions. Furthermore, the specific technical and operational elements required for evaluating the modified helmets were identified, allowing an exhaustive comparative evaluation of the two proposed solutions (i.e., HGU-55P and HGU-55G modified helmets). The initial compatibility problems encountered were progressively mitigated by incorporating modifications in both front and rear cockpits at various stages of the test campaign. This process allowed considerable enhancement of the TORNADO NVIS configuration, giving good medium- to high-level NVG operational capability to the aircraft. Further developments also include the internal/external lighting for the Italian TORNADO “Mid-Life Update” and other programs such as AMX aircraft internal/external light modification/testing and the activities addressing low-altitude NVG operations with fast jets (e.g., TORNADO, AMX, MB-339CD), with a major issue being the safe ejection of aircrew with NVG and NVG modified helmets. Two options have been identified for solving this problem, namely, the modification of the current Gentex HGU-55 helmets and the design of a new helmet incorporating a reliable NVG connection/disconnection device (i.e., a mechanical system fully integrated in the helmet frame) with embedded automatic disconnection capability in case of ejection. Other relevant issues to be accounted for in these new developments are the helmet dimensions and weight, the NVG usable field of view as a function of eye-relief distance, and the helmet's center of gravity (moment arms) with and without NVG (effect on aircrew fatigue during training and real operational missions).

A novel approach to night vision imaging systems development, integration and verification in military aircraft

This paper describes the research and experimental flight test activities conducted by the Italian Air Force Official Test Centre (RSV) in collaboration with industry (Alenia Aeronautica and Litton Precision Products) and with Academia, in order to confer the Night Vision Imaging Systems (NVIS) capability to the Italian TORNADO IDS (Interdiction and Strike) and ECR (Electronic Combat and Reconnaissance) aircraft. The activities included various Design, Development, Test and Evaluation (DDT&E) activities, including Night Vision Goggles (NVG) integration, cockpit instruments and external lighting modifications, as well as various ground test sessions and a total of eighteen flight test sorties. RSV and Litton Precision Products were responsible of coordinating and conducting the design and installation activities of the internal and external lights. Particularly, an iterative process was established, allowing an in-site rapid correction of the major deficiencies encountered during the ground and flight test sessions. Both single-ship (day/night) and formation (night) flights were performed, shared between the RSV and Alenia Test Crews involved in the activities, allowing for a redundant examination of the various test items by all participants. An innovative test matrix was developed and implemented by RSV for assessing the operational suitability and effectiveness of the various modifications implemented. Also important was definition of test criteria for Pilot and Weapon Systems Officer (WSO) workload assessment during the accomplishment of various operational tasks during NVG missions. Furthermore, the specific technical and operational elements required for evaluating the modified helmets were identified, allowing an exhaustive comparative evaluation of the two proposed solutions (i.e., HGU-55P and HGU-55G modified helmets). The results of the activities were very satisfactory. The initial compatibility problems encountered were progressively mitigated by incorporating modifications both in the front and rear cockpits at the various stages of the test campaign. This process allowed a considerable enhancement of the TORNADO-NVIS configuration, giving a good medium-high level NVG operational capability to the aircraft. Further developments also include the internal/external lighting for the Italian TORNADO “Mid Life Update” (MLU) and other programs, such as the AM-X aircraft internal/external lights modification/testing and the activities addressing low-altitude NVG operations with fast jets (e.g., TORNADO, AM-X, MB-339CD), a major issue being the safe ejection of aircrew with NVG and NVG modified helmets. Two options have been identified for solving this problem: namely the modification of the current Gentex HGU-55 helmets and the design of a new helmet incorporating a reliable NVG connection/disconnection device (i.e., a mechanical system fully integrated in the helmet frame), with embedded automatic disconnection capability in case of ejection. Other relevant issues to be accounted for in these new developments are the helmet dimensions and weight, the NVG usable FOV as a function of eye-relief distance, and helmet centre of gravity (moment arms) with and without NVG (impact on aircrew fatigue during training and real operational missions).

Night Vision Imaging Systems Development, Integration and Verification in MilitaryFighter Aircraft

This paper describes the research and experimental flight testactivities conducted by the Italian Air Force Official Test Centre (RSV) in collaboration with Alenia S.p.A. and Cranfiled University, in order to confer the Night Vision Imaging Systems (NVIS) capability to the Italian TORNADO IDS (Interdiction and Strike) and ECR (Electronic Combat and Reconnaissance) aircraft. The activities included various Design, Development, Test and Evaluation (DDT&E) activities, including Night Vision Goggles (NVG) integration, cockpit instruments and external lighting modifications, as well as various ground test sessions and a total of eighteen flight test sorties. RSV and Litton Precision Products were responsible of coordinating and conducting the installation activities of the internal and external lights. Particularly, an iterative process was established, allowing an in-site rapid correction of the major deficiencies encountered during the ground and flight test sessions. Both single-ship (day/night) and formation (night) flights were performed, shared between the Test Crews involved in the activities, allowing for a redundant examination of the various test items by all participants. An innovative test matrix was developed and implemented by RSV for assessing the operational suitability and effectiveness of the various modifications implemented. Also important was definition of test criteria for Pilot and Weapon Systems Officer (WSO) workload assessment during the accomplishment of various operational tasks during NVG missions. Furthermore, the specific technical and operational elements required for evaluating the modified helmets were identified, allowing an exhaustive comparative evaluation of the two proposed solutions (i.e., HGU-55P and HGU-55G modified helmets). The results of the activities were very satisfactory. The initial compatibility problems encountered were progressively mitigated by incorporating modifications both in the front and rear cockpits at the various stages of the test campaign. This process allowed a considerable enhancement of the TORNADO NVIS configuration, giving a good medium-high level NVG operational capability to the aircraft. Further developments also include the internal/external lighting for the Italian TORNADO “Mid Life Update” (MLU) and other programs, such as the AM-X aircraft internal/external lights modification/testing and the activities addressing low-altitude NVG operations with fast jets (e.g., TORNADO, AMX, MB-339CD), a major issue being the safe ejection of aircrew with NVG and NVG modified helmets. Two options have been identified for solving this problem: namely the modification of the current Gentex HGU-55 helmets and the design of a new helmet incorporating a reliable NVG connection/disconnection device (i.e., a mechanical system fully integrated in the helmet frame), with embedded automatic disconnection capability in case of ejection. Other relevant issues to be accounted for in these new developments are the helmet dimensions and weight, the NVG usable FOV as a function of eye-relief distance, and helmet centre of gravity (moment arms) with and without NVG (impact on aircrew fatigue during training and real operational missions).

高分辨率中红外温度自适应夜视成像系统

高分辨率中红外温度自适应夜视成像系统

Developing Quantum Dot Phosphor‐Based Light‐Emitting Diodes for Aviation Lighting Applications

We have investigated the feasibility of employing quantum dot (QD) phosphor‐based light‐emitting diodes (LEDs) in aviation applications that request Night Vision Imaging Systems (NVIS) compliance. Our studies suggest that the emerging QD phosphor‐based LED technology could potentially be superior to conventional aviation lighting technology by virtue of the marriage of tight spectral control and broad wavelength tunability. This largely arises from the fact that the optical properties of semiconductor nanocrystal QDs can be tailored by varying the nanocrystal size without any compositional changes. It is envisioned that the QD phosphor‐based LEDs hold great potentials in cockpit illumination, back light sources of monitor screens, as well as the LED indicator lights of aviation panels.

Preparation of a Novel Night Vision Imaging System Filter for Display Applications

A novel NVIS filter based on NIR-dyes and polymer film was prepared through a special designed method. The relation between optical performance and NIR-dye content was discussed. The optical properties of the filter can be easily controlled by changing the amount of NIR-dyes. The results showed there was a good linear relationship between absorbance value and amount of NIR-dyes. Then, a filter with optimal amount of NIR-dyes was prepared. The filter showed strong absorbing ability in the region between 660nm and 930nm. Meanwhile, it showed sufficient transmittance between 400nm and 630nm. At last, an environmental test was taken to evaluate the performance stability of the filter.

Flight Tests of the KO-1 Aircraft at Night

The KO-1 aircraft which has the functionality of tactical observation, was successfully developed in August of 2004 in South Korea. It is important for the KO-1 aircraft to achieve successful missions at nighttime as well as during daytime. The aircraft, equipped with interior and exterior lighting systems and lighting control panel modified from those of the KT-1 basic trainer, provides improved safety, operational effectiveness, and situational awareness during operation at night when used with night-vision goggles (NVGs). KO-1 is the first domestic aircraft that utilizes the night-vision imaging system (NVIS) technology in Korea. KO-1 NVIS was developed with the goal of defining the components of NVIS and establishing test and evaluation procedures for both the subsystems and main system. In this paper, we present the establishment of a KO-1 NVIS lighting system, NVIS component development, and representative ground and flight test results.

저속통제기 야시조명계통 개발

This paper deals with a development of night vision imaging system(NVIS) for the KO-1 aircraft. In the modern combat, NVIS has a tendency to be applied for night peculiar mission and pilot mission maximization. KO-1 aircraft, which was the first domestic applied NVIS, is forward air control acquired information of day/night enemy(foe) site and moving of enemy for low altitude flight. We have successfully finished a developmental requirement/criterion, development of system, and construction of test and evaluation through development of NVIS for the KO-1 aircraft. KO-1 aircraft is acquired timely initial operational capability.

Compatibility of aircraft cockpit lighting and image intensification night imaging systems

Night imaging systems based on image intensification (12) tubes are a major factor in the night operation capability of military aircraft. A major problem associated with the use of these systems is the detrimental effect on performance caused by internal cockpit lighting. Instrument lamps, caution lamps, utility lights, and other light sources inside the cockpit activate the automatic gain control circuits of the intensification tubes, thereby reducing their sensitivity to external natural and artificial illumination. In 1986, a tn-service specification, MIL-L-85762, Lighting, aircraft, interior, night vision imaging system compatible7 was adopted to resolve the cockpit lighting problems. MIL-L-85762 defines the measurement instrumentation and techniques required to certify lighting components as Night Vision Imaging System (NVIS) compatible. Ongoing efforts related to MIL-L-85762 include characterization of lighting incompatibilities in current U.S. Army aircraft, implementation of programs to modify the lighting in incompatible cockpits, and certification of proposed lighting components for future aircraft systems.