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Laser dazzling of focal plane array cameras - art. no. 65431B

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Laser dazzling of focal plane array cameras - art. no. 65431B

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Laser countermeasures against infrared focal plane array cameras aim to saturate the full camera image. In this paper we will discuss the results of three different dazzling experiments performed with MWIR lasers and show that the obtained results are independent of the read-out mechanism of the camera and can be explained by an expression derived from the point spread function of the optics. This expression also allows us to estimate the required laser power to saturate a complete focal plane array in a camera system. Simulated Images with simulated dazzling effects based on this expression will be shown.
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... Another approach is the use of complementary wavelength bands in optical sensors to avoid image information lost in case of laser dazzle [11]. Laser dazzling of sensors was intensively studied experimentally and theoretically by various groups [12][13][14][15][16][17][18], including approaches to quantify the performance of protection measures [19,20]. ...
... The calculation of the focal plane irradiance distribution for camera sensors has been already accomplished by several researchers, for example, by Schleijpen et al. [12], Benoist et al. [14] or Özbilgin et al. [29]. Their work aimed to estimate the size of a dazzle spot in cameras or thermal imagers. ...
... From the work of Schleijpen and Benoist, we can learn that it is mandatory to include scattering of light from the camera lens to explain the extent of dazzle spots at higher irradiance levels. In their earlier work, scattering was simply described by a constant referring to the irradiance level in the focal plane [12]. In later work, a scatter function of the form • Θ was introduced [14]. ...
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This publication presents an approach to adapt the well-known classical eye-related concept of laser safety calculations on camera sensors as general as possible. The difficulty in this approach is that sensors, in contrast to the human eye, consist of a variety of combinations of optics and detectors. Laser safety calculations related to the human eye target terms like Maximum Permissible Exposure (MPE) and Nominal Ocular Hazard Distance (NOHD). The MPE describes the maximum allowed level of irradiation at the cornea of the eye to keep the eye safe from damage. The hazard distance corresponding to the MPE is called NOHD. Recently, a laser safety framework regarding the case of human eye dazzling was suggested. For laser eye dazzle, the quantities Maximum Dazzle Exposure (MDE) and the corresponding hazard distance Nominal Ocular Dazzle Distance (NODD) were introduced. Here, an approach is presented to extend laser safety calculations to camera sensors in an analogous way. The main objective thereby was to establish closed-form equations that are as simple as possible to allow also non-expert users to perform such calculations. This is the first time that such investigations have been carried out for this purpose.
... Across the entire electro-optical and infrared domains, there are similarities in the way that detectors are affected by the exposure to laser radiation. For example, Benoist and Schleijpen 5 while implementing a model predicting the overexposed pixels of visible CCD cameras due to laser dazzling, showed this was also in good agreement with results presented by Schleijpen et al. 6 for mid and long-wave infrared imagers. In a further example, the images from dazzled sensors were studied to estimate the loss of information due to the dazzle spot 7 . ...
... The purpose of this article is to show experimental evidence highlighting the impact of in-band laser radiation on a vanadium oxide microbolometer array; particularly, how the pixels are perturbed and eventually damaged due to an increase in laser power density. In this section, we discuss the most pertinent findings with focus on the following nonlinear effects 6 : damage to the pixels, pixel saturation and diffraction patterns. ...
... At a higher power density of approximately 6x10 8 pW/cm 2 , pixels in the central lobe are fully saturated. We were not able to corroborate our results with the observed cubed root dependency on laser irradiance by Benoist and Schleijpen 5 , for which they stated agreement with that found by Schleijpen et al. 6 for the dazzling of thermal infrared detectors of photon type. ...
... As the missile approaches its target, a digital data-processing system constructs an image of it and compares it with typical target patterns stored in the processor's memory. Therefore, it is virtually impossible to "spoof " such missiles by jamming them with a pulsed IR laser [2,3,9]. ...
... The functional damage of the PDA achieved in this way is associated with the reversible effect of saturation of the sensor array when it is irradiated with laser radiation having a radiation power substantially greater than that for suppressing the IR imaging seekers of the preceding generation with a single detector and with a scanning head. It was sufficient in the latter case to create modulated noise whose power was not much greater than the signal from the target [3,9]. ...
... Depending on the power of the laser radiation incident on the detector area of the PDA, with a wavelength that coincides with its spectral sensitivity region, various effects are possible that result in temporarily or completely disabling it, the main ones of which are given in Table 1. The experimental results obtained for various types of PDAs [2,3,[6][7][8][9][10] were taken into account when setting up the table. It is noteworthy that there is no definite boundary between the jamming effect and dazzling, which can occur simultaneously. ...
Article
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This paper discusses existing and prospective laser devices for countermeasure systems that operate in the IR region. Attention is mainly devoted to questions of counteracting imaging seekers that function in the IR region and of suppressing thermal-vision observation, reconnaissance, and aiming equipment. Our critical analysis of the available literature data makes it possible to conclude that quantum-cascade lasers can be used in creating promising compact multispectral IR countermeasure systems. Estimates are given of how much radiation power quantum-cascade lasers need for the functional suppression of remote photodetector devices. The results of the calculations are in satisfactory agreement with the available literature data. It is shown that existing ways of enhancing the radiation power of quantum-cascade lasers make it possible to achieve the values needed to use them in IR countermeasure systems. © 2017 Optical Society of America
... Поэтому одним из важных направлений создания новых образцов вооружения и военной техники является разработка систем и средств ОЭП. Они предназначены для снижения эффективности, функционального подавления или поражения оптоэлектронных приборов различного назначения (тепловизионные средства разведки, наблюдения и прицеливания, головки самонаведения управляемых ракет и др.)[2][3][4]. При подавлении тепловизионных средств (ТПС) противника атакующая сторона может получить решающее преимущество, поэтому в современных условиях противодействие им должно стать составной частью защиты всех родов войск. ...
... По мере сближения ракеты с целью система цифровой обработки данных строит ее изображение и сравнивает с образами типовых целей, заложенных в память процессора. Поэтому «обман» таких ракет с помощью постановки импульсным ИК лазером помех станет практически невозможным[2,3,9]. В качестве наиболее перспективного метода противодействия ракетам с ИК ГСН, снабженными МФПУ, сейчас рассматривается не постановка помех, а «ослепление» ракет излучением непрерывного или квазинепрерывного импульсного лазера, длина волны излучения которого попадает в область чувствительности ИК МФПУ. ...
... Достигаемое при этом функциональное повреждение МФПУ связано с обратимым эффектом насыщения массива чувствительных элементов матрицы при облучении ее лазерным излучением с мощностью излучения существенно большей, чем для подавления ИК ГСН предыдущего поколения с одним детектором и со сканирующей головкой. В последнем случае достаточно было создания модулированной помехи с мощностью, не намного превышающей сигнал от мишени[3,9]. В зависимости от мощности лазерного излучения, падающего на приемную площадку МФПУ, с длиной волны, совпадающей с областью его спектральной чувствительности, возможны различные эффекты, приводящие к временной или полной его неработоспособности, основные из которых представлены в таблице. ...
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Full-text available
Рассмотрены существующие и перспективные лазерные средства для систем противодействия, работающих в инфракрасном диапазоне спектра. Основное внимание уделено вопросам противодействия головкам самонаведения, функционирующим в инфракрасной области спектра, и подавления тепловизионных средств наблюдения, разведки и прицеливания. Проведенный критический анализ имеющихся литературных данных позволяет сделать вывод о том, что квантово-каскадные лазеры могут быть использованы при создании перспективных мультиспектральных компактных систем противодействия инфракрасного диапазона. Приводятся оценки мощности излучения квантово-каскадных лазеров, необходимой для функционального подавления удаленных фотоприемных устройств. Результаты расчетов находятся в удовлетворительном согласии с имеющимися литературными данными. Показано, что существующие пути повышения мощности излучения квантово-каскадных лазеров позволяют достичь необходимых значений для их применения в системах инфракрасного противодействия. Ключевые слова: оптико-электронные системы противодействия, инфракрасные головки самонаведения, тепловизионные средства наблюдения, разведки и прицеливания, квантово-каскадные лазеры.
... 9,10 Regarding sensors, laser dazzling was intensively studied experimentally and theoretically by various groups. [11][12][13][14][15][16][17][18] The measurement of laser-induced damage thresholds of imaging sensors is also an important and ongoing topic. [18][19][20] Protection against laser dazzle faces the challenge that nowadays lasers are available with any wavelength in the visible spectral range. ...
Article
The use of complementary wavelength bands in camera systems is a long-known principle. The camera system's spectral range is split into several spectral channels, where each channel possesses its own imaging sensor. Such an optical setup is used, for example, in high-quality three-sensor color cameras. A three-sensor camera is less vulnerable to laser dazzle than a single-sensor camera. However, the separation of the individual channels is not high enough to suppress cross talk, and thus, all three channels will suffer from laser dazzling. To solve that problem, we suggest two different optical designs in which the spectral separation of the channels is significantly increased. The first optical design is a three-channel camera system, which was already presented earlier. The second design is a two-channel camera system based on optical multiband elements, which delivers undisturbed color images even under laser dazzle. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.
... Notice that with the exception of the diffraction pattern, the image in Figure 5 closely resembles many of the phenomena shown in an image by Schleijpen et. al 21 , which is widely reproduced in other articles 4,22 . We are unclear why the images at the lower of the two power densities in Figure 3 suggests a diamond shaped a central saturated region rather than the more typical circle cross-section. ...
... 8,9 Laser dazzling of sensors was intensively studied, experimentally and theoretically, by various groups. [10][11][12][13][14][15][16] Laser dazzle protection seems to be a simple issue, but it faces the challenge that lasers are available with any wavelength in the visible spectral range. Classical laser protection measures, such as absorption or interference filters, used in laser eye protection goggles cannot provide protection for all wavelengths. ...
Article
We present an optical concept for imaging sensor systems, designed to considerably reduce the sensor's image information loss in cases of laser dazzle, based on the principle of complementary bands. For this purpose, the sensor system's spectral range is split in several (at least two) spectral channels, where each channel possesses its own imaging sensor. This long-known principle is applied, for example, in high-quality three-sensor color cameras. However, in such camera systems, the spectral separation between the different spectral bands is too poor to prevent complete sensor saturation when illuminated with intense laser radiation. We increased the channel separation by orders of magnitude by implementing advanced optical elements. Thus, monochromatic radiation of a dazzle laser mainly influences the dedicated transmitting spectral channel. The other (out-of-band) spectral channels are not or - depending on the laser power - only hardly affected. We present our system design as well as a performance evaluation of the sensor concerning laser dazzle.
Article
Based on the model of electro-optical imaging guided seeker by using the gate centroid tracking method, four models of laser jamming including bright-spot jamming, bright-spot with bright-strip jamming, whole saturation jamming, and blinding jamming were established according to the characteristic of the output image of the electro-optical imaging guided seeker jammed by laser. Theoretical analyses indicated that the effect of the bright spot jamming was equivalent to the bright spot with bright strip jamming, and the effect of whole saturation jamming was equivalent to the blind jamming. The influences of laser jamming on the parameters of electro-optical imaging guided missile including the guidance voltage, guidance error angle, ballistic trajectory and the impact point were studied systemically by using the laser jamming simulation software of the electro-optical imaging guided missile. The simulating results are consistent with the theory analysis.
Article
A simple model has been developed and implemented in Matlab code, predicting the over-exposed pixel area of cameras caused by laser dazzling. Inputs of this model are the laser irradiance on the front optics of the camera, the Point Spread Function (PSF) of the used optics, the integration time of the camera, and camera sensor specifications like pixel size, quantum efficiency and full well capacity. Effects of the read-out circuit of the camera are not incorporated. The model was evaluated with laser dazzle experiments on CCD cameras using a 532 nm CW laser dazzler and shows good agreement. For relatively low laser irradiance the model predicts the over-exposed laser spot area quite accurately and shows the cube root dependency of spot diameter on laser irradiance, caused by the PSF as demonstrated before for IR cameras. For higher laser power levels the laser induced spot diameter increases more rapidly than predicted, which probably can be attributed to scatter effects in the camera. Some first attempts to model scatter contributions, using a simple scatter power function f(θ), show good resemblance with experiments. Using this model, a tool is available which can assess the performance of observation sensor systems while being subjected to laser countermeasures.
Conference Paper
Laser countermeasures against infrared focal plane array cameras aim to saturate the full camera image. In this paper we will discuss the results of dazzling experiments performed with MWIR lasers. In the "low energy" pulse regime we observe an increasing saturated area with increasing power. The size of the saturated area can be explained by an expression derived from the point spread function of the optics. The experimental results for short "high energy" pulses show a strong non-linear response of the detector arrays. Physical processes potentially responsible for these effects are described. Possible consequences of this non-linear detector behaviour for the effectiveness of laser countermeasures applying short high energy pulses are discussed. A better understanding of the response of infrared detectors to short high energy laser pulses, will allow changing the laser design in order to mitigate these effects.
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NATO-SCI-139 and its predecessor groups have more than a decade of history in the evaluation and recommendation of EO and IR Countermeasures against anti-aircraft missiles. Surrogate Seekers have proven to be a valuable tool for this work. The use of surrogate seekers in international co-operations has several advantages over the use of an operational seeker, which is in service or in development: 1) the system is flexible, allowing both hardware and software modifications to be made in order to test the effectiveness of specific IRCM techniques; 2) the seeker design is open - every last parameter is available to the science team, allowing detailed, end-to-end validation of software models and simulations; 3) the availability of an unclassified seeker facilitates open discussions on CM issues between the participants in the NATO-group. Testing of high intensity countermeasures (for example based on lasers) needs a system with realistic seeker optics, with proper representation of optical scatter in seeker optics, which differs from scatter in commercial infrared camera optics. A technical description of the ISS is given: an overview of the optical design and the detector, the principle of the tracking software and the possibilities to implement alternative tracking algorithms in order to represent different threat CCM techniques. The ISS is built for use both in the laboratory and in the field. Finally, some experimental results will be presented.
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Retro-reflection can be used for the detection and classification of optical systems. The probability of detecting sights over large ranges depends on parameters of the laser, the sight, the detector and the atmosphere. We have developed a software tool that simulates a sight detection system. With the use of this tool we can 'test' different sight detection system designs and make estimations on detection ranges of optical systems. In this paper we give a short overview of the physical aspects that have been implemented in the model and discuss the experimental validation of our model.
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Countermeasures against heat seeking missiles require access to efficient laser sources, which should emit wavelengths at band I, II and IV. Efficient diode pumped solid-state lasers, combined with efficient non-linear wavelength shifters, allow the development of practical tuneable mid-IR countermeasure sources. The paper describes the requirements and the development of a tabletop laser source for study of DIRCM techniques. Jamming laser systems must be able of creating pulse sequences in the frequency range between 100 Hz and 10,000 Hz, including the capability to mix and sweep the jam frequency. A Nd:YVO4 pump laser with maximum pump power of 3 Watt and pulse length of 10 ns, and a maximum modulation frequency of 100 kHz was selected. A linear single resonant OPO cavity with 30 mm long, 1mm thick PPLN crystals was build. With the tabletop laser system we were able to generate wavelengths from 1.5 to 4 micron. In band I, at 2 micron we can generate between 400-550 mW, and in band II, from 3-4 micron we can generate 130-160 mW laser jam power. The beam quality (M2) is approximately 2.5. The power efficiency for the idler was 8.8%, while the slope power efficiency was 15%. Jam patterns are generated by use of an acousto-optic modulator.
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The design and analysis of achromatic doublet prisms for use in laser beam steering is presented. The geometric relationships describing the maximum steering angle are given, as are discussions of first- and second-order dispersion reduction. Infrared (IR) material alternatives and optimum IR material characteristics for wide-angle achromatic prism beam steering are also investigated. Sixteen materials in 120 different combinations have been examined to date. For midwave IR applications it is shown that the minimum dispersion currently achievable across the full 2 to 5 mum spectrum is 1.7816 mrad at an average maximum steering angle of 45 deg. This is accomplished using LiF/ZnS doublet prisms. Several issues related to the azimuth and elevation angles into which light is steered as a function of prism rotation angles are also presented. (C) 2003 Society of Photo-Optical Instrumentation Engineers.
Laser dazzling of focal plane array cameras
  • L Arjan
  • Herman Mieremet
  • Benoit Bekman
  • Mellier
Arjan L. Mieremet, Herman Bekman, and Benoit Mellier, Laser dazzling of focal plane array cameras, Proc. SPIE 6738, p. 67380O, 2007. c 2008 SPIE