This PDF file contains the front matter associated with SPIE Proceedings Volume 11537, including the Title Page, Copyright Information, and Table of Contents.

We would like to welcome you to this year’s Electro-Optical and Infrared Systems: Technology and Applications XVII Conference which was originally due to take place in Edinburgh, UK. However, the Covid-19 pandemic, as well as affecting the lives and activities of many people, has made it necessary to replace our 2020 Conference with an online event. For many scientists and engineers, attending a conference is not just about hearing presentations on the latest research and development work. The chance to catch up with our peers and make new contacts over a coffee between the presentations is almost, if not, as equally important. The importance of such ‘in-the-margins’ conversations is well recognised by SPIE, and they have made enormous efforts to maximise opportunities for virtual discussions instead. However, the absence of the informal networking and interaction remains a loss to many of us, and we hope that normality returns for future conferences. The impact of the pandemic has wrong-footed many experts and politicians in terms of both its scale and dynamics. Within this turmoil, our conference organisers have been faced with the enormous challenge of trying to plan an international meeting, and we suspect that many of us are not fully aware of the pressure and frustration that they have faced. To the knowledge of these Conference Chairs, there have been at least three incarnations of the Conference: a four-day event, a three-day event, and finally the online event. We therefore believe that it is important to acknowledge here the efforts of the SPIE staff members who not only worked tirelessly to enable the Edinburgh conference to go ahead, but adjusting swiftly to the online format when events moved against us. On a more personal note, we are pleased to announce that SPIE has honoured Dr Dave Huckridge by appointing him as a SPIE Fellow. Many of you will know Dave Huckridge who was our Conference Chair for the first fifteen years of its existence and who did so much to grow the event in terms of both the number of attendees and the quality of the presentations. It was planned to present him with his award in Edinburgh, but regrettably this became impossible when the decision to go online was made. Nonetheless, we would like to thank Dave Huckridge for his contributions to our community over many years. We would also like to thank David Titterton, Roger Appleby, and Keith Lewis for sponsoring the application within SPIE. Our Conference is a very important part of our community and it provides a forum for the exchange of innovative thoughts and development across a spectrum that ranges from basic research through to system designs and applications. Few other international events offer such breadth and depth for the defence and security sector, and this is reflected through its ongoing popularity with both academia and industry. Many of our authors have faced not only the uncertainty of travel but also restrictions by their funding organisations. To those who were unable to submit their work this year, we thank you anyway, and hope that you will consider returning to our Conference next year. However, and despite these uncertainties, we have been pleased with the number of authors who have been able to contribute papers, as well as acknowledging the quality of their research and development work. Despite the problems that we have all faced, it is an encouraging sign to see that the creation of new ideas and sensor concepts has not stopped. The Electro-Optical and Infrared Systems: Technology and Applications Conference provides a forum for researchers and designers to present their latest work, and for all of us to gain an insight into how such developments can meet the needs of current and future sensor-based systems and their applications. Having an applications-focus is invaluable: it offers a means of interpreting and analysing technology in a real-world context where benefits can be readily understood in terms of both capability and implementation potential. The Conference also brings together technologists, designers, systems engineers, and end-users: the essential stakeholders needed to take ideas and technology forward. We have retained the same overall structure for the Conference as last year, with principal sessions on Sensors and Technology, Systems and Applications, Image and Data Processing, and Modelling and Simulation. This is a broad technology canvass, but it is one that is needed to provide the framework required to understand sensor technology and their interfaces from a system perspective. Distributed across these topics, we have received approximately 30 contributions which offer new insights and ideas into detectors and camera technology, sensor system concepts and their applications, the exploitation of scene information and its extraction, and new approaches for modelling and simulation at both components and system levels. Whilst we may not be able to meet in person this year, our community has shown a strong resilience and collective spirit for maintaining open dialogue and the free exchange of ideas. We therefore conclude by once again thanking our authors for their contributions and hoping that the online participants find the papers of interest and beneficial to their own ongoing research and development work.

We report an approach to build a tunable spectral imaging system operating in the long-wave infrared (λ=8-12 μm). In addition to broadband images, the imaging systems allows for tunable selection of particular passbands. The tunable passband selection allows the imaging system to focus on the infrared signatures (including both thermal emission signature related to object’s temperature and characteristic absorption signature) of object of interest. This is achieved by incorporating a fast tunable spectral filter comprising dispersive magneto-optic (MO) materials in the imaging system. The MO materials in the spectral filter are sandwiched between polarizers, and dispersion in the Faraday Effect rotates the polarization of different wavelengths of light by different amounts, which results in a wavelength-dependent attenuation by the subsequent polarizer. Multiple stages with different thicknesses of the MO material can be stacked (Lyot configuration) to further narrow down the transmission peak. The central wavelength of the filter can be tuned either by tuning the magnetic field B along the direction of the optical axis, or by rotating the polarizers while applying a fixed magnetic field. In the long-wave infrared, n-doped InSb proves to be a prominent MO material. We present detailed measurements of Verdet constant, absorption coefficient and calculated figure of merit (FOM) for a range of carrier concentrations near 10¹⁷ cm^-3 in the long-wave infrared. A prototype tunable bandpass filter is constructed and demonstrated.

Uncooled FIR-imagers decreased in pixel pitch from latest state-of-the-art value of 17 µm to 10 µm. Following this trend of a reduction of pixel size, Fraunhofer IMS provides a manufacturing process for FIR-imagers (IRFPAs) based on a scalable microbolometer technology. Beside conventional approaches of a thermal isolation of microbolometer membranes realized by lateral legs, Fraunhofer IMS developed a manufacturing process for a thermal isolation realized by nanotubes. To demonstrate the scalability of the nanotube-microbolometers the nanotube contact is applied to microbolometer membranes with 12, 10, 8 and 6 µm pixel size on top of a 17 µm digital readout integrated circuit (ROIC). The arrays are sealed by a chip-scale vacuum package to evaluate the microbolometers’ performance by means of a complete IRFPA. Quantitative measurement results for the responsivity as well as qualitative test pictures of the 12, 10 and 8 µm nanotube-microbolometers will be presented. A direct visual comparison in a test scene demonstrates no obvious decrease in sensitivity between 12 and 8 µm. Only at 6 µm pixel size a reduced sensitivity is observed. In summary, a fully working uncooled IRFPA with QQVGA resolution based on a 6 µm nanotube-microbolometer technology is presented here. The scalability of the nanotube-microbolometer technology from state-of-the-art pixel sizes down to 6 µm is demonstrated.

Electro-optic (EO) sensors operating in the reflective and thermal bands are commonly used for a wide range of surveillance applications. Among the ones of interest is the detection of military targets cluttered in natural environment using either broadband or multispectral imaging sensors. Additionally, the spectral information of the elements of a scene under surveillance can be exploited further by hyperspectral imaging (HSI) sensors to provide enhanced detection capability against Army assets thwarted by Camouflage, Concealment, and Deception (CC&D) countermeasure techniques. While innovative camouflages are designed to mimic the spectral signature of various background environments, new advanced hyperspectral imaging sensors having increased sensitivity and spectral resolution are also actively developed. Accordingly, hyperspectral polarimetric imaging sensors have been devised to measure the polarization property of light in addition to the spectral signatures of the elements of a scene. Such imaging sensors provide the capability to improve further the detection of a broad range of target materials buried in various vegetation backgrounds while reducing false alarm rates. This paper investigates the use of ground-based hyperspectral polarimetric sensors to assess the optical performance of camouflage prototypes currently in development for the Canadian Armed Forces (CAF). Unpolarized and polarized radiance measurements of camouflage prototypes deployed in semi-desertic environments were acquired in the visible and shortwave infrared spectral bands. Experimental results demonstrate the benefits of using hyperspectral polarimetric imaging sensors to improve the detection performance of different camouflage prototypes, and open up potential to develop new remote sensing capabilities that are able to deal with improved CC&D countermeasure means.

In this contribution we introduce a compact version of a broadband static Fourier transform spectrometer (bs- FTS) for the mid-infrared spectral range. The bsFTS covers a spectral range from about 4.5 µm to 14 µm, respectively 2220 cm⁻¹ to 700 cm⁻¹ at a spectral resolution of 8 cm⁻¹. As, in contrast to scanning Fourier trans- form spectrometers, the interferogram is modulated not over time but in the spatial domain, the measurement speed is only limited by the detector. This allows for infrared spectroscopy at 25 Hz to 200 Hz using uncooled microbolometer arrays. Besides liquid measurements in attenuated total reflection (ATR), demonstrating the accuracy and linearity of the bsFTS, we show time-resolved analyses of 1,1,1,2-Tetrafluoroethane (R134a) and carbon monoxide test gases to prove the suitability of the system for high-speed spectroscopy.

In a stand-off imaging scenario from a high-altitude airborne platform, the camera line-of-sight (LOS) passes through atmosphere layers of variable density at an oblique angle. Dispersion blur arises because of wavelength-dependent refraction in the atmosphere. In visible-and-near-infrared (VNIR) spectral band the atmospheric dispersion is significant and has some effect onto resolution performance in LOS elevation dimension. Historically the atmospheric refraction and dispersion issues were studied and analyzed in astronomy, considering an infinitely distant celestial body imaged by a ground-based telescope. The calculation involves an atmosphere properties model as well as an expression for air refractive index as function of pressure, temperature and humidity. However, a straightforward application of the star–to-ground telescope refraction formulae to the ground target–toairborne camera case leads to incorrect results. In the latter case boundary conditions for light ray refraction are different, since the ground target-to-camera distance is finite rather than infinite. There are dispersion-related ray angle differences both at departure of light from the target and on arrival to the camera. Only the latter part of the overall atmospheric dispersion is perceived at the camera and causes image blur. An iterative method of the camera-perceived dispersion calculation is presented. Parametric study results illustrate the dispersion dependence on camera altitude and LOS zenith angle. The model results are validated by comparison to vertical-to-horizontal sharpness ratio statistics calculated from images taken by Condor2 cameras at various ranges. The dispersion-related NIIRS grade loss is relatively small, and in most practical cases no optical compensation of the atmospheric dispersion is necessary.

Modulating Transfer Function (MTF) has always been very important and useful for objectives quality definition and focal plane settings. This measurand provides the most relevant information on the optimized design and manufacturing of an optical system or the correct focus of a camera. MTF also gives out essential information on which defaults or aberrations appear on an optical objective, and so enables to diagnose potential design or manufacturing issues on a production line or R&D prototype. Test benches and algorithms have been defined and developed in order to satisfy the growing needs in optical objectives qualification as the latter become more and more critical in their accuracy and quality specification. Many methods are used to evaluate the Modulating Transfer Function. Slit imaging and scanning on a camera, MTF evaluation thanks to wavefront measurement or imaging fixed slanted knife edge on the detector of the camera. All these methods have pros and cons, some lack in resolution, accuracy or don’t enable to compare simulated MTF curves with real measured data. These methods are firstly reminded in this paper. HGH has recently developed an improved and mixed version of a scanning technique used on a slanted knife edge giving a more accurate, ergonomic, high resolution and precise Line Spread Function (LSF) and one axis MTF measurement of a camera. A selected single pixel corresponding to a precise field point of the camera is scanned with sub pixelic resolution by the tilted knife edge thus enabling an optimized accuracy for LSF and MTF curves. The experimental protocol which requires a high-performance collimator, a scanning wheel device and a camera set up is detailed in this paper. Explained simulations are done to prove the under 1% accuracy of this method with regards to the different characteristics of the camera. All the parameters of this improved measurement technique are described and their effect criticized to give out all the result influence of these variables. These simulations and the algorithms used are then confronted to real measurements on a camera thanks to a mirror-based collimator and a scanning wheel device equipped with a slanted knife edge target.

In order to characterize the performance of visible digital imaging systems in the laboratory, in the field and in simulation, the use of fractal test-targets has been optimized. This work is based on the previous achievements in the use of binary fractal targets (2014) and the Corner-Point (CP) resolution criterion (2017), for DRI range modeling of optronic cameras. The principle is to resume from the process of multi-scale fractal calculation of the binary target, to extend it in the case of a multi-level of gray. The distribution of CP contrasts by scale is then adapted to two constraints, on the one hand the measurement accuracy and on the other hand the criterion definition of the operational task evaluated for the camera. A target will be specifically designed to accommodate an operational need, such as the identification of vehicles or handheld weapon. The exploitation of the fractal target degraded by the imager is carried out by the comparison of CP by scales with the original target, after an image registration phase, facilitated by an original Yin-Yang design of the target at its lowest CP scale. The main metric for assessing DRI range is the Resolved Contrast Function (RCF), obtained from the multi-scale CP Probability of Correct Resolution. In the first part of the paper, the principles of design and exploitation of the target are presented, applied to an example of a DRI range assessment of a camera coupled to image restoration processing. In a second part, the use of this evaluation technique is developed in the example of digital image fusion systems, from two bands with its own optronic characteristics and some non-linear digital processing. This work, carried out in simulation using the FUSIM software, allows to establish a selection of the optimal combinations (pre-processing, fusion processing) offering the best RCF.

In this paper, we model a real-time feasible rosette imager, consisting of a rosette scanner, an optical sensor and a deterministic image reconstruction algorithm. We fine-tune the rosette imager through selecting the appropriate sensor field of view and rosette pattern. The sensor field of view is determined through a greedy approach using uniform random sampling. Furthermore, the optimal rosette pattern is selected by determining which pattern best covers the imaging area uniformly. We explore image sparsity, image decimation and Gaussian filtering in a well-known natural data set and dead leaves data set using the PSNR, Peak-Signal-to-Noise Ratio. This exploration helps to establish a connection between PSNR and image sparsity. Furthermore, we compare various rosette imager configurations in a Bayesian framework. We also conclude that the rosette imager does not outperform a focal-plane array of equivalent samples in terms of image quality but can match the performance.

The current development of increasingly sensitive low-light detector technologies in the VNIR/SWIR regions shows many promises for future night vision applications, including digital image fusion. By combining spectral bands from the reflective and the thermally emissive domains, providing complementary band-specific cues and advantages, it is anticipated that a fused representation will increase situational awareness and target discrimination performance. Performance assessment of image fusion still remains an open problem however, as suitable procedures, models and image quality metrics are still largely missing. A night-time data collection was made on a side-aspect two-hand object identification task over several ranges in a rural/woodland area using a common line-of-sight VNIR/LWIR system. Perception experiments based on an 8-alternative forced choice (8AFC) object ID task were performed, on both the two individual bands as well as several common pixel-based fusion algorithms (including maximum, subtraction and averaging). As image fusion is highly task and scene dependent it is difficult to draw any general conclusions from a single experiment, but for the particular task/scene combination investigated most of the fusion algorithms are shown to perform better than the VNIR channel, albeit most of them fail to perform as well as the LWIR. This is thought to be the result of the VNIR channel being contrast-limited for the particular task/scene being studied and the low dynamic range of the low-light EBCMOS camera used in the fusion setup.

The process of geometric camera calibration for long-wave infrared (LWIR) camera is essential for determining the camera’s intrinsic and extrinsic parameters, which maps 3D world coordinate points onto 2D image coordinate points. In this paper, new calibration board materials are proposed for making a plane checkerboard to calibrate the LWIR camera. These materials are low-cost items and, to the best of our knowledge, has not been used so far for calibration of infrared camera. The resulting calibration board exhibited high thermal infrared image contrast and showed consistent checkerboard corners’ detection to accomplish the geometric calibration of LWIR wavebands camera. The suggested method is tested using three different LWIR cameras in an indoor environment. The quality of new proposed board thermal imaging is compared with existing calibration board made by paint. The calibration approach is experimented using “MATLAB Single Camera Calibrator Tool” for each of the three LWIR cameras and showed that the overall calibration mean reprojection error is less than 0.35 pixel. The proposed calibration board is beneficial in terms of precision, low-cost built-up and easy reusability.

There is a growing interest in the fusion of Visible colour (RGB) and Near Infrared (NIR) imagery in the field of remote sensing. In this paper, RGB and NIR image fusion (RGBN) is considered from a security and surveillance perspective. An RGBN fusion scheme is proposed which successfully uses a Colour Weight Map (CWM) to control colour distortion and enhance the visibility of features of interest within the scene. The RGBN fusion design used is a simple arithmetic solution that can be readily implemented in hardware, and can operate at high camera frame rates. Performance of the processing scheme is evaluated both qualitatively and quantitatively. For the latter, image metrics have been developed for both colour and greyscale evaluation, and the metric set includes a modified version of the Structural Similarity Index Measure (SSIM). Results obtained from visual inspection and metric analysis are reviewed and shown to be well correlated.

Plasmonic metamaterials are artificial structures whose optical response can be tailored to achieve several effects by playing with the geometrical parameters of the components. In this talk, we discuss how to apply the metamaterial design rules to develop band-stop linear filters and nonlinear filters, operating as intensity limiters. In both regimes, the filters share some common qualities: their optical response does not change for a broad range of incidence angles, at least up to 30 degrees, and is only weakly dependent on the polarisation of the incident light. These properties make these ultrathin filters useful in open field applications. The metamaterial is based on an array of gold nanotubes (i.e., a cylindrical gold shell with a dielectric core) embedded in a dielectric matrix. In the linear regime, the metamaterial displays an absorption resonance independent of the polarisation and the angle of incidence of the light, which can be tuned throughout the visible spectral range by changing the geometrical parameters of the array. In the nonlinear regime - based on free-electron Au nonlinearity and tested with ns-long pulses at 532 nm - the metamaterial limits the output peak fluence, keeping it constant across several order of magnitudes of the incoming fluence. The proposed metamaterial approach can be useful for designing optical spectral filters and intensity limiters over broad range of wavelengths.

Opto-electronic devices destined for space must be suitably radiation-hard, meaning that they must be resilient to the effects of high energy radiation in space. For high performance IR (infrared) space-based applications, the current material of choice is MCT (Mercury Cadmium Telluride). MCT is difficult and therefore expensive to fabricate and the constituent materials are becoming increasingly restricted by regulation. The new generation of barrier diode detectors based on III-V materials offer a promising alternative to MCT, providing comparable performance whilst offering devices that are compatible with volume manufacturing processes. As part of a DASA Space-to-Innovate Phase 1 funded project we have developed a novel radiation hard unipolar barrierbased ABaT™ III-V MWIR diode detector. The detector is being subjected to gamma and proton radiation testing to demonstrate its suitability for space environments. To compare the radiation performance of this diode, a number of other typical III-V detector diode structures have been fabricated and tested. In this paper we present the results of the project so far and future plans to develop this into detector arrays.

The detection of lasers by means of coherence detection often uses interferometry in a one-dimensional manner such as with a Mach Zehnder interferometer. We are taking a two dimensional approach making use of a spatial light modulator and a camera to examine the results of binary holography in differentiating coherent and incoherent incoming light. A DMD micromirror array focusing light onto a CCD camera is presented as a method for determining the presence of coherent light, its wavelength and angle of arrival. We discuss the use of Zernike modes to overcome the aberrations inherent in the DMD device, thereby improving the focussing quality and improving the precision of wavelength determination.

Since the 1960s range finding through the use of Laser Imaging, Detection, and Ranging (LIDAR)^1-4 and Range Gated Active Imaging (RGAI)^{5, 6} has been explored. Presently, these processes of range finding are considered as fast and reliable methods for determining distance in the domestic, commercial and defence environments. Both technologies share benefits such as fast measurement time, high accuracy and resolution, and the ability to carry out measurements remotely. While both methods utilise a laser and some form of detector to measure distance, this is where the similarities end. LIDAR typically creates a 3D point cloud of the scene by scanning the laser across the scene and measuring the travel time for the laser pulse, usually recorded by a single pixel detector. RGAI on the other hand, illuminates a scene at a fixed repetition rate and moves the gate of the sensor, operating at the same frequency as the laser, in time with respect to the output of the laser. The sensor, usually a focal plane array (FPA), records the incident light while the gate is open. A depth map can then be built where the observed depth is related to the delay between the laser firing and the gate opening. The depth of the image correlates to the time the gate is open; the longer the exposure time, the deeper the image. These methods for range finding predominantly use lasers and detectors that operate in the Near Infrared (NIR)⁷ and Short Wave Infrared (SWIR),^{8, 9} usually around the telecom wavelengths. For these wavelengths, there exist multiple options for single pixel detectors that are inherently fast, leading to a high temporal resolution for LIDAR, or in the case of RGAI, detectors that can be gated with short on-time windows.^{10, 11} The choice to move from the visible range to longer wavelengths is due to the reduced effect of atmospheric scattering, relative saftey for the retina of the eye and mature market of fast lasers and detectors necessary for high temporal resolution. The reduced effect of atmospheric scattering and transmission through obscurants to the visible range is a huge benefit.¹² The use of Medium Wave Infrared (MWIR) and Long Wave Infrared (LWIR) in range finding is a relatively unexplored area, apart from a handful of experiments and government projects in the 80s^13-16 and later on in the late 2000s.¹⁷ There exists numerous high power, short rise time IR lasers which will enable a high resolution measurement. The main factor delaying the development in the MWIR and LWIR is attributed to the fact that detectors currently on the market are generally either very sensitive, but have a long rise time, or they are relatively fast but tend to sacrifice sensitivity.^{18, 19} This leads to either obtaining inaccurate results or needing a very high power laser and longer integration time to achieve reliable results. However, the use of the longer wavelengths could herald many advantages such as an increased range because of greatly reduced scattering - the MWIR and LWIR bands both include large transmission windows spanning 3 µm and 8 − 12 µm spectral windows.²⁰ The use of longer wavelength range will reduce the likelihood of damage caused to the eye retinas due to inability to penetrate the outer tissue.^{21, 22} Our research aims to overcome this problem by externally gating a slow but sensitive detector to achieve high resolution at low laser power illuminating the scane. To accomplish this we designed and built an all-optical modulator comprising of an 808 nm diode laser to illuminate a semiconductor window. The transparency of the window can be modulated between the states of nearly full transparency to opaqueness when the laser pulse is absorbed. The rate of change of transparency follows that of the laser pulse's leading edge. This group of components is further referred to as the modulator. Since there are no moving parts involved in the modulator this would be a perfect drop-in replacement for more traditional mechanical style shutters. A solid state shutter, with all-optical modulation would be more rugged and less susceptible to shocks, g-forces and offer fewer points of wear and tear, increasing logenvity of the device with benefits offering faster activation times. This could be used for shorter exposures and faster reaction times to overexposure, potentially reducing damage caused to sensors under high illumination. Another added advantage of the modulator is the possibility to modulate the signal between totally on and totally off. IR modulators available today are either mechanical, such as optical choppers and shutters, or electro-optical such as LCD style technology,²³ Pockels cells and acousto-optic modulator. While LCD technology offers a solid state solution to IR modulation, it does not offer the speed that our technology could achieve. This paper looks into the feasibility of an active imaging LWIR system for use in RGAI applications and LWIR time-of- ight range finder using the all-optical solid state modulator technology. The signal is provided by a LWIR, 10:07 µm Hamamatsu Quantum Cascade Laser (QCL). To assess the abilities of the range-finding a Mercury Cadmium Telluride (MCT) detector was used to detect the LWIR laser pulse. The setup included two separate optical paths, with one being approximately 18m longer than the other. It was found that we were able to reliably discern a difference between the two optical paths. For active imaging an uncooled Thermoteknix camera was used to image an object placed in the beam path before the modulator. It was found that it was possible to gate the camera with such timing that the image of the object, with an illumination time of 20 µs, would almost disappear entirely from the scene.

Coherent lidar sensors provide a useful resource in a sensor suite, allowing high dynamic range, near quantum limited sensitivity, and derivation of phase, frequency and intensity information from the received light. However, a conventional system can only provide single pixel detection, requiring the pixel to be scanned over the scene to produce an image, the rate of which is limited by mechanical bandwidths. Alternatively, a direct detection focal plane array (FPA) can provide many pixels to image a full scene but lacks the required bandwidth for militarily useful data product. The HiPAR (High Pixel Acquisition Rate) program is developing a proof of principle system to combine the advantages of coherent lidar with the simultaneous multi-pixel acquisition advantages of an FPA. In a novel optical arrangement, a line of laser light is projected onto the scene. Backscatter from the line is then mixed in the receive path with a local oscillator which matches the received image and the two, interfering fields are imaged onto an FPA producing a single coherent line image. Phase differences between the scene and local oscillator fields – e.g. due to Doppler shift or intentional modulation – cause the short-term irradiance in the line to fluctuate both spatially (along the line) and in time. Spatial variation is adequately sampled by FPA pixels but, in general, temporal fluctuation will significantly exceed FPA frame rate. To overcome the bandwidth limitations, the system is configured to rapidly sweep the line across the FPA so that the temporal fluctuations are captured as spatial variations in the second dimension. The FPA behaves as an “optical storage oscilloscope”, similar in concept to a streak camera. High sweep rates allow interference modulation rates far in excess of frame rate to be captured. Thus, high bandwidth coherent information can be derived from a line of pixels across the scene. By using a scanning mirror in the transmit/receive chain, the line imager can be scanned over an entire scene to build up a full image for Doppler or range-finding purposes, with line acquisition proceeding at FPA frame rate. This paper presents the physical principles of the system, the progress to date and the initial results.

When analyzing images in the far-infrared spectrum, the problem of separation of objects arises on the given temperature ranges. The simple threshold separation is hindered by the presence of a noise component. This task is most relevant when used to on weak computing systems and organizing data processing onboard the device (or mobile device). This problem may arise during data analysis: during processing onboard aircraft (UAV), automated control systems for robotic systems, security and access control systems, etc. In article proposes an approach that allows solving the problem of separating a thermal imaging image to objects within specified ranges. The approach is step-by-step image processing using the filtering and blurring method based on multicriteria image preprocessing. A method for changing the bitrate and a method for detecting objects based on the density of similar pixels in a given analysis sliding window. The filtering and blurring method is adapted and accelerated for implementation on low-performance computing modules. As a result of developing the method, we managed to lower the computational requirements. However, this slightly increases the time of preprocessing. The article describes in detail the algorithm for changing the multicriterial method, shows of changes in characteristics and their influence on the result. A method is proposed for changing the gradation of IR image ranges, based on multiple changes on the section gradient. The on a step-by-step merging algorithm for adjacent ranges is based on the use of adaptive weighting factors. The coefficients are determined automatically and depend on the frame. The method of final separation into objects is based on an analysis in the sliding window, we analysis of the number of different elements and the allocation of close objects in groups. The methods and algorithms proposed in the work are adapted for calculations on devices with reduced requirements for computational costs. On the set of test images obtained by portable thermal imaging cameras (SEEK with a resolution of 320 by 240 pixels) from the UAV, car, and street, we present the effectiveness of the application of the approach introduced in the article.

The display of information characterizing the distribution of thermal gradients is associated with the formation of a twodimensional image. A thermal image is most often a group of objects with varying intensities. This picture is due to physical aspects. Most often, the thermal background does not have a clear boundary, and therefore the use of conventional methods for detecting special features in the form of angles or borders is not applicable. In the previously described works, a method was proposed for identifying special features based on the search for the midline, for closed objects. This approach did not take into account the possibility of changing the degree of growth of the line displacement, which may be correct provided that a pair of objects of different temperatures adjoin each other and there is information about this. The article proposes to develop a modification of the search method an equidistant curve that allows you to introduce a curve growth function. The difference from the original approach is the possibility of regulating the degree of movement of the internal or external borders in the direction of the neighbor. The approach proposed in the work includes the operations of filtering, changing the color space, changing the color range, and searching for stable signs. The task is relevant and may also be applicable in tasks: increasing the clarity of x-ray images; eliminate blur in photos; preprocessing images obtained in the visible spectrum; deblurring images obtained in motion, etc. In the article on a set of test data shows the applicability of the proposed approach for identifying stable features in thermal imaging images. The data obtained by FLIR C2 and SEEK thermal imaging cameras cover a wide range of possible applications from analysis of data obtained outside buildings, as well as technical processes occurring inside mechanisms.

SPARTAN is a multimedia shooting training system that uses optoelectronic solutions such as simulated firing with a laser technology, infrared detection of the points of impact projectiles of training and live ammunition, the use of adapted nightvision and thermal sights for shooting. It is designed to teach, monitor and evaluate the targeting of small arms and to prepare soldiers for firing the live ammunition at open ranges for combat targets and silhouettes. It is also intended for the preparation of soldiers for detection, classification and engagement of real targets upon different terrains, weather conditions and periods during the day. The aim of the paper is to assess the impact of the system on the soldiers training process as well as the economic aspects of its application. This system in the Polish Armed Forces, in various configurations, has been used for several years, so it is possible its preliminary analysis.

Linear Astigmatism Free - Three Mirror System (LAF-TMS) is a confocal off-axis system that eliminates linear astigmatism, which is the most critical aberration especially in the large field angle, and therefore, enables the telescope to have a wide field of view. Based on our experience with the telescope, we optimized the LAF-TMS for wavelength ranges of mid-wavelength infrared (3-5 µm) and long-wavelength infrared (8-12 µm) sensors onboard Unmanned Aerial Vehicles (UAVs). It has an entrance pupil diameter of 70 mm, a focal ratio of 1.4, and a wide field of view (FoV) of 6.20° × 4.68°, matching 10.9 mm × 8.2 mm sensor with 17 µ m sized pixels (LAF-TMS D70F1.4). The freeform mirrors of LAF- TMS D70F1.4 are optimized to eliminate the high order aberration. As a result, LAF-TMS D70F1.4 can achieve high- quality optical performance over a wide FoV without any additional correcting lenses. We performed the sensitivity analysis and the Monte-Carlo simulations as the feasibility study. During the sensitivity analysis and the Monte-Carlo simulation, decenter, tilt, despace, and surface RMS errors of three mirrors were analyzed. From the sensitivity analysis, we investigated 80% Energy Encircled Diameter by single factor perturbations. The system tolerance limits were calculated using the Monte-Carlo method with a normal distribution of errors. According to the results, we confirmed that the LAF-TMS D70F1.4 was feasible considering general fabrication and alignment tolerances.

Two approaches have been proposed for distinction objects by third generation thermal imagers are discussed in the report. The first approach is based on recalculation of the original Johnson’s criteria and the second one is based on the dependences of the minimum resolvable temperature difference and temperature contrast on spatial frequency. In this paper, the most sensitive parameters are determined for optimization the numerical objects distinction by third generation thermal imagers.

We consider in this paper the problem of image inpainting in infrared image analysis, where the objective is to reconstruct missing or deteriorated parts of an image. In this work, we develop image inpainting using quaternion representation concepts and modified exemplar-based technique. In our work, we exploit the concept of sparse representation, which takes a group of nonlocal patches with similar textures as the basic unit instead of a patch. As a result, the proposed method provides plausible restoration while propagating information of edge for the target region. Experimental inpainting results demonstrate the effectiveness of the proposed method in the task of reconstruction thermal images.