Proceedings Volume 7481

Electro-Optical and Infrared Systems: Technology and Applications VI

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Proceedings Volume 7481

Electro-Optical and Infrared Systems: Technology and Applications VI

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Volume Details

Date Published: 5 October 2009
Contents: 8 Sessions, 35 Papers, 0 Presentations
Conference: SPIE Security + Defence 2009
Volume Number: 7481

Table of Contents

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Table of Contents

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  • Front Matter: Volume 7481
  • Sensor Processing and Scene Modeling
  • Spectral and Multiband Sensors I
  • Spectral and Multiband Sensors II
  • Detectors
  • Sensors and Related Technologies I
  • Sensors and Related Technologies II
  • Poster Session
Front Matter: Volume 7481
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Front Matter: Volume 7481
This PDF file contains the front matter associated with SPIE Proceedings Volume 7481, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.
Sensor Processing and Scene Modeling
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Model-based object recognition in range imagery
The paper formulates the mathematical foundations of object discrimination and object re-identification in range image sequences using Bayesian decision theory. Object discrimination determines the unique model corresponding to each scene object, while object re-identification finds the unique object in the scene corresponding to a given model. In the first case object identities are independent; in the second case at most one object exists having a given identity. Efficient analytical and numerical techniques for updating and maximizing the posterior distributions are introduced. Experimental results indicate to what extent a single range image of an object can be used for re-identifying this object in arbitrary scenes. Applications including the protection of commercial vessels against piracy are discussed.
A framework for the development and assessment of target classification algorithms
R. Hansford, M. Nicholas
This paper describes the design and implementation of a framework used to develop and assess novel classification algorithms applied to imagery from diverse sources, such as in-service thermal sensors and experimental burst illumination lasers. The framework is designed to aid with the development of algorithms where both high classification performance and fast execution are required. It addresses the issue of how to effectively divide development time and effort between the potentially conflicting tasks of improving performance and speed. The development of the framework and its implementation in MATLAB® are described, along with three short case studies showing its application during recent projects.
Approximate non-parametric feature extraction applied to classification system data
Kathrin Dorn, Sabino Gadaleta, Can Altinigneli
Within a Classification System (CS), prior to classification, feature extraction techniques are used to reduce the dimensionality of features. A standard unsupervised technique is the Principal Component Analysis (PCA). In this paper we apply a supervised method for feature extraction, the Non-Parametric eigenvalue-based Feature Extraction (NPFE), to CS data sets and compare the performance of the two different feature extraction schemes based on classification accuracies obtained with the LVQ cluster algorithm. Furthermore, to reduce computational complexity of NFPE, we introduce an approximate NFPE and show that it provides significantly reduced computation time with almost identical performance as in the full NPFE algorithm.
Assisted interpretation of infrastructure facilities from aerial imagery
The evaluation of a country's critical infrastructure requires a detailed analysis of facilities such as airfields, harbors, communication lines and heavy industry. To improve the interpretation process, an interactive support system for the interpretation of infrastructure facilities from aerial imagery is developed. The aim is to facilitate the training phase for beginners, increase the flexibility in the assignment of interpreters and improve the overall quality of the interpretation. An analysis of the approach chosen by professional interpreters has been the basis to identify critical steps which can be effectively supported by a software system. To evaluate the benefit of the system, an experimental setup is proposed.
Thermal scene analysis via finite element model and finite difference time domain numerical solution of the electromagnetic wave propagation in the short wave and long wave infrared bandarch
We utilize the Finite Element Model (FEM) and Finite Difference Time Domain (FDTD) numerical solution of the Electromagnetic wave propagation in the Short Wave Infrared (SWIR) and Long Wave Infrared (LWIR) bands in order to calculate the target radiance propagation and environment attenuation due to transmission, absorption and reflections in atmosphere and obstacles. We leave to traditional minimum resolvable temperature (MRTD) the model of the camera radiance collection (actual thermal sensitivity of the camera). The main advantage of the numerical propagation is that there is the possibility to model exactly the specific target shape and the specific environment (depending of the computational power) and calculate the residual temperature.
pcSitoS: a new tool for image-based IR system simulation
H.-J. Greif, A. R. Weiss, W. Wittenstein
Analytical range performance models like NVThermIP and TRM have proved very useful in the development, procurement, and quality control of thermal imaging systems. The analytical approach, however, cannot produce images usable for the visualization of expected capabilities of a planned system or suitable for observer experiments. In order to overcome this limitation, a software package, pcSitoS, was developed at FGAN-FOM that implements most of the features covered by the analytical modeling package TRM but is capable of producing simulated high-quality output images for a given IR system. The simulation model is presented and examples of simulated imagery from both scanning and staring thermal imaging systems are shown.
Spectral and Multiband Sensors I
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A new imaging FTIR spectroradiometer
Louis Moreau, Claude Roy, Christian Vallières, et al.
ABB Bomem is expanding its line of infrared remote sensing products with the addition of a new imaging spectroradiometer. That hyperspectral instrument is based on the proven MR FTIR spectroradiometers. This field instrument, called the MR-i, is a fast imaging Fourier Transform spectroradiometer. It generates spectral data cubes in the MWIR and LWIR. It is designed to be sufficiently fast to acquire the spectral signatures of rapid events. The design is modular. The two output ports of the instrument can be populated with different combinations of detectors (imaging or not). For instance to measure over a broad spectral range, one output port can be equipped with a LWIR camera while the other port is equipped with a MWIR camera. No dichroics are used to split the bands, hence enhancing the sensitivity. Both ports can be equipped with cameras serving the same spectral range but set at different sensitivity levels in order to increase the measurement dynamic range and avoid saturation of bright parts of the scene while simultaneously obtaining good measurement of the faintest parts of the scene. Various telescope options are available for the input port. This is a presentation of the current state of the development.
Spectral and Multiband Sensors II
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Ultraviolet through infrared imager performance testing
The objective of any imaging system is to optimize the amount of pertinent information collected from a scene. Whether it is used for artistic reproduction, scientific research, or camouflage detection, a camera has the same ultimate requirement. In the era of broadband, multi-spectral, hyperspectral, and fused sensor systems, both spectral and spatial data continue to play battling roles in determining which is dominant in how well an imaging system meets its definitive objective. Typically sensor testing requires hardware and software exclusively designed for the spectral region of interest. Thus an imaging system with ultraviolet through infrared imaging capabilities could require three or more separate test benches for sensor characterization. Obviously this not only increases the complexity, and subsequently the cost of testing, but also more importantly tends to produce discontinuous results. This paper will outline the hardware and software developed by the authors that employ identical test methods and shared optics to complete infrared, visible, and ultraviolet sensor performance analysis. Challenges encompassing multiple emitting source switching, splitting, and combining will be addressed along with new single fused type source designs. Decisions related to specifying optics and targets of sufficient quality and construction to provide coverage of the full spectral region will be discussed along with sample performance specifications and data. Test methodology controlled by a single automated software suite will be summarized including modulation transfer function, signal to noise ratio, uniformity, focus, distortion, intrascene dynamic range, and sensitivity. Selected examples of results obtained by this test set will be presented.
Improved target detection by IR dual-band image fusion
Dual-band thermal imagers acquire information simultaneously in both the 8-12 μm (long-wave infrared, LWIR) and the 3-5 μm (mid-wave infrared, MWIR) spectral range. Compared to single-band thermal imagers they are expected to have several advantages in military applications. These advantages include the opportunity to use the best band for given atmospheric conditions (e. g. cold climate: LWIR, hot and humid climate: MWIR), the potential to better detect camouflaged targets and an improved discrimination between targets and decoys. Most of these advantages have not yet been verified and/or quantified. It is expected that image fusion allows better exploitation of the information content available with dual-band imagers especially with respect to detection of targets. We have developed a method for dual-band image fusion based on the apparent temperature differences in the two bands. This method showed promising results in laboratory tests. In order to evaluate its performance under operational conditions we conducted a field trial in an area with high thermal clutter. In such areas, targets are hardly to detect in single-band images because they vanish in the clutter structure. The image data collected in this field trial was used for a perception experiment. This perception experiment showed an enhanced target detection range and reduced false alarm rate for the fused images compared to the single-band images.
Application of heterogeneous multiple camera system with panoramic capabilities in a harbor environment
Piet B. W. Schwering, Henk A. Lensen, Sebastiaan P. van den Broek, et al.
In a harbor environment threats like explosives-packed rubber boats, mine-carrying swimmers and divers must be detected in an early stage. This paper describes the integration and use of a heterogeneous multiple camera system with panoramic observation capabilities for detecting these small vessels in the Den Helder New Harbor in the Netherlands. Results of a series of experiments with different targets are presented. An outlook to a future sensor package containing panoramic vision is discussed. We also investigated several aspects of the use of electro-optical systems. As for classification, this paper concentrates on discriminating classes of small vessels with different electro-optical systems (visual and infrared) as part of the larger process involving an operator. It addresses both selection of features (based on shape and texture) and ways of using these in a system to assess threats. Results are presented on data recorded in coastal and harbor environments for several small targets.
Multispectral system for perimeter protection of stationary and moving objects
Mieczyslaw Szustakowski, Wieslaw M. Ciurapinski, Marek Zyczkowski, et al.
Introduction of a ground multispectral detection has changed organization and construction of perimeter security systems. The perimeter systems with linear zone sensors and cables have been replaced with a point arrangement of sensors with multispectral detection. Such multispectral sensors generally consist of an active ground radar, which scans the protected area with microwaves or millimeter waves, a thermal camera, which detects temperature contrast and a visible range camera. Connection of these three different technologies into one system requires methodology for selection of technical conditions of installation and parameters of sensors. This procedure enables us to construct a system with correlated range, resolution, field of view and object identification. The second technical problem connected with the multispectral system is its software, which helps couple the radar with the cameras. This software can be used for automatic focusing of cameras, automatic guiding cameras to an object detected by the radar, tracking of the object and localization of the object on the digital map as well as identification and alarming. In this paper two essential issues connected with multispectral system are described. We focus on methodology of selection of sensors parameters. We present usage of a spider-chart, which was adopted to the proposed methodology. Next, we describe methodology of automation of the system regarding an object detection, tracking, identification, localization and alarming.
Detectors
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Advanced III/V quantum-structure devices for high performance infrared focal plane arrays
Robert Rehm, Martin Walther, Johannes Schmitz, et al.
A mature production technology for Quantum Well Infrared Photodetector (QWIP) focal plane arrays (FPAs) and InAs/GaSb superlattice (SL) FPAs has been developed. Dual-band and dual-color QWIP- and SL-imagers are demonstrated for the 3-5 μm and 8-12 μm atmospheric windows in the infrared. The simultaneous, co-located detection of both spectral channels resolves the temporal and spatial registration problems common to existing bispectral IRimagers. The ability for a reliable remote detection of hot CO2 signatures makes tailored dual-color superlattice imagers ideally suited for missile warning systems for airborne platforms.
Latest developments in MCT for next generation of infrared staring arrays
This paper presents an overview of the very recent developments of the MCT infrared detector technology developed by CEA-LETI and Sofradir in France for next generation of applications. New applications require high sensitivity and dual band detectors. The Avalanche PhotoDiodes (APD) technology opens new interesting fields of investigation for low flux applications and fast detectors for laser imaging. IR sensors for this type of application are synchronized with eye-safe lasers, and have to detect a weak signal backscattered from the target on the order of 10 photons per pulse. They also have to be able to operate with a very short integration time, typically one hundred nanoseconds, in order to gate the backscattered signal around the target. In partnership with Sofradir, CEA/LETI (France) has developed high quality MCT avalanche photodiodes satisfying these requirements. In parallel, specific studies have been carried out at the Read-Out Circuit level to develop optimized architectures. Thanks to these advances, a new Integrated Dewar Detector Cooler Assembly has been developed. This new product presented in this paper is the first step in a road-map to address low flux infrared sensors in the next few years. In parallel, the development of dual-band infrared detectors has been the core of intense research and technological improvements for the last ten years. New TV (640 x 512 pixels) format detectors of 24μm pixel pitch is available. It is proposed with MWIR/MWIR or MWIR/LWIR dual band sensitivity integrated in dedicated tactical Dewars. At present, focused on pixel pitch reduction, Sofradir is carrying out optimization of the materials quality, photodiode design as well as flip-chip bonding process. 20 μm pixels have demonstrated dual color key performances (quantum efficiency, optical fill factor, and pixel operability) in accordance with mono-spectral structures. Results are presented in this paper.
Activation and evaluation of GaN photocathodes
Gallium Nitride (GaN) photocathodes are potentially attractive as UV detective materials and electron sources. Based on the activation and evaluation system for GaAs photocathode, which consists of ultra-high vacuum (UHV) activation chamber, multi-information measurement system, X-ray photoelectron spectroscopy (XPS), and ultraviolet ray photoelectron spectroscopy (UPS), the control and measurement system for the activation of UV photocathodes was developed. The developed system, which consists of Xenon lamp, monochromator with scanner, signal-processing module, power control unit of Cs and O source, A/D adapter, digital I/O card, computer and software, can control the activation of GaN photocathodes and measure on-line the spectral response curves of GaN photocathodes. GaN materials on sapphire substrate were grown by Metal-Organic Chemical Vapor Deposition (MOCVD) with p-type Mg doping. The GaN materials were activated by Cs-O. The spectral response and quantum efficiency (QE) were measured and calculated. The experiment results are discussed.
Novel technology for polymer-based microbolometers
Andreas Nocke, Marcus Wolf, Helmut Budzier, et al.
This work investigates the ability to integrate conductive polymer compounds as self-supporting sensitive layers in microbolometers. The polymer matrix is a photoresist that can be structured by UV-lithography and hardened to a highly cross-linked phenolic resin by thermal curing. The electrically conductive filler material is tellurium being synthesized as (nano)rods with an average diameter of 250 nm and an average length of 5 μm. To fabricate microbolometers pixel elements an appropriate technology was developed with the motivation to use cost-efficient polymeric materials and processing steps. It includes a sacrificial layer technique and a dielectrophoretic alignment procedure of the tellurium nanorods. The resulting electrical conducting network in the polymer matrix has a temperature coefficient of resistance (TCR) of -1.4 % / K that yield the bolometric effect. The TCR-value and the resistance are determined by the intrinsic properties of the tellurium nanorods and the characteristics of the hopping conduction occurring between neighboring tellurium nanorods. The electrical properties can be tailored by the alignment procedure to some extent. However, there is an interrelation between a high TCR and a high resistance.
Uncooled amorphous silicon IRFPA for high performance and high volume applications
D. Pochic, A. Durand, J. L. Tissot, et al.
For more than 10 years now, uncooled sensors have given new opportunities in the IR field of applications by being able to be produce in large volume. Compared to cooled technology, uncooled detectors offer many interesting advantages: high reliability, lower cost ... whereas the performance is high enough for a lot of applications. Thermography, building inspection, enhanced driver vision and military (thermal weapon sight, low altitude UAV sensor) are applications which can be provided with affordable IR focal plane arrays... As uncooled IR sensors are mainly dedicated to these high volume applications, any uncooled IRFPA technology has to be able to provide high performance sensors but also to be producible in large volume at a minimum cost. The high level of accumulated expertise by ULIS and CEA/LETI on uncooled microbolometers made from amorphous silicon layer enables ULIS to develop a full range of IRFPA formats from 160x120 to 1024x768 pixels with 25μm and 17μm pixel-pitch, designed for high end and high volume applications. The detector ROIC designs rely on a simple architecture (detector configuration addressed by a serial link for user defined amplifier gain, windowing capability...) which enables easier systems upgrade and therefore a reduced system development non recurrent cost. The packaging technique depends on the application environment and the production volume in order to fit with the market expectation. Starting from metallic and ceramics package, very advanced new technique is under development in order to reduce uncooled IRFPA production cost. NETD in the range of 30mK (f/1, 300K, 60Hz) as well as operability higher than 99.99%, are routinely achieved with amorphous silicon technology.
Sensors and Related Technologies I
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Flexible 640 x 480 pixel infrared camera module for fast prototyping
Alain Bergeron, Loïc Le Noc, Bruno Tremblay, et al.
In various military, space and civilian infrared-based applications, there is an important need for fast prototyping. At the very heart, stands a requirement for flexible camera modules that provides a multitude of output formats as well as fast adaptability. Based on this concept, INO has developed an advanced compact camera module that can provide both raw data output as well as fully processed images under a variety of formats such as NTSC, PAL, VGA and GigE. This tool can be used to perform a rapid demonstration of an application concept. The IRXCam-640 camera core is a very flexible module that is based on a 640 x 480 pixels uncooled FPA but which may be rapidly modified to accommodate for other resolutions and sensor types. Providing 16-bit raw signal and 8-bit final image outputs at 60 Hz, the electronics gives total access to the detector configuration parameters. The output is available in NTSC, PAL, and GigE. An additional VGA output can be used as input for a microdisplay. TECless operation minimizes module size and power consumption. If required for absolute measurements, a TEC integrated to the detector package can be controlled with external electronics. The camera core can be configured for outdoors operation from -30°C to +60°C with 200°C scene dynamic range at maximum sensitivity. Windowing capability provides flexibility of frame frequency and operating field of view. The camera can be further coupled with a microscan mechanism to provide a high resolution 1280 x 960 pixel image. In this paper, the camera module is reviewed as well as its performances.
Modelling a crime scene in 3D and adding thermal information
Once a crime has been perpetrated, forensic traces will only be persevered in the crime scene for a limited time frame. It is therefore necessary to record a crime scene meticulously. Usually, photographs and/or videos are taken at the scene to document it, so that later on one will know the exact place of an object. Another possibility is to construct a three dimensional (3D) model of the crime scene. A 3D model has the advantage that you can change the perspective and view the scene from all directions. We use a stereo camera to record the crime scene and use these images to construct a 3D model. A drawback of conventional (color) cameras is that they only capture features that belong to the visible part of electromagnetic spectrum. Interesting traces with strong signatures in other parts of the spectrum could be overlooked. For example; has a lamp or computer screen been turned on previously, is there some fluid on the carpet? Such traces can be observed with an infrared (IR) camera that captures images in the IR part of the spectrum. However, it is not well understood if these traces stay visible for a sufficient amount time. Therefore, a first set of experiments was conducted to gain some insight in the visibility degradation of different IR traces over time. The results are discussed in this paper. Furthermore, it will be shown how adding thermal information to the 3D model can improve crime scene understanding.
A technique for ghosting artifacts removal in scene-based methods for non-uniformity correction in IR systems
Alessandro Rossi, Marco Diani, Giovanni Corsini
In this work we analyze the problem of the ghosting artifacts coming out from non-uniformity correction (NUC) in infrared focal-plane array (IRFPA) imaging systems. We have employed a well-established least mean square (LMS) - based NUC technique which was first introduced by D.A. Scribner. Slow global motion and edges in the scene are the main responsible of the generated ghosting artifacts that can be very damaging especially in target detection and tracking applications. To mitigate the effects of ghosting we propose to replace the linear spatial filter of the analyzed NUC scheme with a non-linear one, known in the literature as bilateral filter, which is able to preserve edges. The proposed technique has been evaluated over an infrared (IR) image sequence with simulated fixed-pattern noise (FPN). A detailed analysis of the results has shown the advantages of the novel deghosting method in terms of accuracy of the calibration and quality of the corrected frames.
Method of detectors offset correction in thermovision camera with uncooled microbolometric focal plane array
Grzegorz Bieszczad, Tomasz Orżanowski, Tomasz Sosnowski, et al.
A microbolometer is an uncooled thermal sensor of infra-red radiation. In thermal imaging, microbolometers organized in arrays called focal plane arrays (FPA) are used. Because of technological process microbolometric FPAs features unwanted detector gain and offset nonuniformity. Because of that, the detector matrix, being exposed to uniform infrared radiation produces nonuniform image with superimposed fixed pattern noise (FPN). To eliminate FPN, nonuniformity correction (NUC) algorithms are used. The offset of detector in array depends from mean temperature of FPA. Every single detector in matrix has its temperature drift, so the characteristic of every detector changes over temperature. To overpass this problem, a temperature stabilization of FPA is commonly used, however temperature stabilization is a relatively power demanding process. In this article a method of offset calculation and correction for every detector in array in function of mean array temperature is described. The method of offset temperature characteristic estimation is shown. The elaborated method let to use unstabilized microbolometric focal plane array in thermographic camera. Method of offset correction was evaluated for amorphous silicon based UL 03 04 1 detector array form ULIS.
Pyroelectric sensors and classification algorithms for border / perimeter security
Eddie L. Jacobs, Srikant Chari, Carl Halford, et al.
It has been shown that useful classifications can be made with a sensor that detects the shape of moving objects. This type of sensor has been referred to as a profiling sensor. In this research, two configurations of pyroelectric detectors are considered for use in a profiling sensor, a linear array and a circular array. The linear array produces crude images representing the shape of objects moving through the field of view. The circular array produces a temporal motion vector. A simulation of the output of each detector configuration is created and used to generate simulated profiles. The simulation is performed by convolving the pyroelectric detector response with images derived from calibrated thermal infrared video sequences. Profiles derived from these simulations are then used to train and test classification algorithms. Classification algorithms examined in this study include a naive Bayesian (NB) classifier and Linear discriminant analysis (LDA). Each classification algorithm assumes a three class problem where profiles are classified as either human, animal, or vehicle. Simulation results indicate that these systems can reliably classify outputs from these types of sensors. These types of sensors can be used in applications involving border or perimeter security.
Controllable time dependent and dual band emission infrared source to test missile warning systems in-flight: system characterization
Dario Cabib, Larry Davidzon, Amir Gil
Proliferation and technological progress of Mid Wave Infrared (MWIR) sensors for Missile Warning Systems (MWS)1,2 and increased sophistication of countermeasures require more demanding in-flight testing. Spectral discrimination is being introduced for higher specificity and lower false alarms. As a result, testing such spectrally more capable systems requires a more spectrally capable stimulator. In a previous paper3 we have described a system we developed to test missile warning systems mounted on an aircraft. The system is placed in the field and projects a time dependent infrared beam towards the flying aircraft, simulating the infrared emittance of an approaching missile in the 3 to 5 micron spectral range as sensed by an MWS system. It can be used also as a trainer for the pilot himself to practice his/her reaction to being targeted. Now we have developed a new system based on the above concept but allowing the user to synchronously produce time profiles of two different infrared ranges independently within the 3 to 5 micron range (3.5 to 4 and 4.5 to 4.8 μ). This new dual color system (the DCIRTS) can now be used stationary or mounted on a vehicle while traveling, for even more realistic simulation. In this paper we describe the DCIRTS and its capability. The system design and preliminary test data were presented in two previous papers (references 4 and 5), but now after having done additional work, we present here additional performance results: expected and measured angular dependent intensity, whose behavior is important in the design of the simulation experiment.
Optimizing the design of electro-optical micro-satellite imagers for ship detection using a real-time simulator
Fabian D. Lapierre, Alexander Borghgraef, Marijke Vandewal
For locating maritime vessels longer than 45 meters, such vessels are required to set up an Automatic Identification System (AIS) used by vessel traffic services (VTS). However, when a boat is shutting down its AIS, there are no means to detect it in open sea. In this paper, we use Electro-Optical (EO) imagers for non-cooperative vessel detection when the AIS is not operational. As compared to radar sensors, EO sensors have less complex system (lower cost and lower payload) and better computational processing load. EO sensors are mounted on LEO micro-satellites. We propose a simulator providing an estimate of sensor Receiver Operating Characteristics (ROC) curves in real-time and without computing the entire image received at the sensor. This simulator can help sensor manufacturers in optimizing the design of EO sensors.
Development of a real time multiple target, multi camera tracker for civil security applications
Hans Åkerlund
A surveillance system has been developed that can use multiple TV-cameras to detect and track personnel and objects in real time in public areas. The document describes the development and the system setup. The system is called NIVS Networked Intelligent Video Surveillance. Persons in the images are tracked and displayed on a 3D map of the surveyed area.
Sensors and Related Technologies II
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Optical limiting performance of nanoparticles in liquid and solid media
S. Dengler, G. Ritt, B. Eberle
We present our investigation of the optical limiting behaviour of different metal and semiconductor nanoparticles in liquid and solid media. Nonlinear transmission measurements were performed by the use of nanosecond laser pulses at 532 nm and 1064 nm. For the various nanoparticles in liquid media large differences in the limiting response were found. Foremost the solid state samples are promising in terms of laser protection devices.
Protection of optical systems against laser radiation
G. Ritt, S. Dengler, B. Eberle
Both the increasing use of laser devices on the battlefield and the misuse of laser devices in civil environments (e.g. dazzling of pilots during approach) necessitate laser protection devices. Conventional laser protection filters based on absorption or interference effects only work in narrow wavelength bands and are usually not neutral in colour. Thus, they are not appropriate for such scenarios. Optical power limiting devices based on nonlinear optical effects (nonlinear absorption, nonlinear refraction, induced scattering) were proposed to offer broadband laser protection without disturbing the visual colour impression. Usually, optical nonlinear materials are examined in laboratory setups which are different from realistic optical systems. We report on the integration of nonlinear laser protection devices into different optical systems to prove the performance of limiting for commonly used optical systems.
MTF measurement of infrared optical systems
Andre Lengwenus, Patrik Erichsen
Advances in electro-optic and infrared systems have led to new ways in modeling complex objectives for IR imaging devices. One important indicator for the performance of an imaging system is the modulation transfer function (MTF). In this contribution we disclose the main aspects of IR-MTF measurement and focus on the ImageMaster® Universal IR product line from Trioptics GmbH Germany. These devices cover the whole spectral range from SWIR to LWIR and can be configured to measure optical systems with focal lengths between 1 mm and 2000 mm. The instrument is fully automatized to a very high degree, so it is suitable for laboratory use as well as instruments designed for the high volume production environment.
Spectral matching factors between low-light-level and infrared fusion optoelectronic detector and objects
Lei Liu, Yinghao Fan, Benkang Chang
According to the response of photoelectric device to a light source, the formula of spectral matching factor of low-lightlevel and infrared fusion optoelectronic detector-object combination is deduced. The spectral matching factors of photo cathode and infrared detector for green vegetation are calculated and compared. Through the analysis of results it shows that spectral matching factor has influence on the performance of low light level and infrared fusion night vision system.
Poster Session
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Contribution of generation-recombination processes at inner interface of MBE-grown Hg1-xCdxTe heterostucture to dark current of small active area photodiode
Galina V. Chekanova, Albina A. Drugova, Viacheslav Kholodnov, et al.
Multilayer heterostructures of Hg1-xCdxTe alloy grown by Molecular Beam Epitaxy (MBE) on large size alternative substrates Si, GaAs and Ge are considered as one of productive alternative materials for issue of large format photovoltaic (PV) infrared (IR) focal plane arrays. However reaching of ultimate performance of small-pitched photodiode's (PD) covering spectral range from 8 to 12 μm depends on electronic properties of both individual layers and heterostructure interfaces. Due to small thickness of heterostructure layers, interfaces are located close to active regions of p-n junction and hence generation-recombination processes at interfaces will contribute to value of current flowing through junction. As usual measured dark current value of small-sized PD is higher than estimated from calculation and cannot be explained by discrepancy between real and estimated charge carriers concentration in absorption layers where p-n junction is formed. Objective of the present work was to calculate the contribution of recombination of charge carriers via electronic states on nearby inner interface to dark current of Hg1-xCdxTe LWIR PD (λco equals to 9.5-10.3 μm at Top=77 K) and its variation with absorption layer parameters and compare it to measured data on small-pitched arrays. We have concluded previously that at high recombination rate dark current can grow in orders of value.
Contribution to the study of night-time driving devices with thermal cameras and EMCCD
The reaction time to the occurrence of unexpected events is essential in night-time driving which uses thermal cameras and EMCCD cameras. The present work analyses the implications of monochrome and coloured observation, of in-depth perception of the distance field, of visual accuracy of the display characteristics that the image is shown on, and of the detection matrices corresponding to the two cameras. The paper also looks at the significant impact of the ambient humidity on the fatigue increase due to prolonged observation. The study also contains a comparative analysis of the observation with, and without a reticle in the evaluation of distance elements from the observed scene. The experiments the present study is based on have been realised using a simulation software in LabVIEW. The work presents also particular case studies to be used in the practical analysis of the reaction time to the driving of vehicles and monitoring their traffic during day or night, with the display of the image on LCD. The experiments were based on films acquired in different ambient conditions, with clear atmosphere, with fog or snowing.
Data fusion concept in multispectral system for perimeter protection of stationary and moving objects
Wieslaw Ciurapiński, Rafal Dulski, Mariusz Kastek, et al.
The paper presents the concept of multispectral protection system for perimeter protection for stationary and moving objects. The system consists of active ground radar, thermal and visible cameras. The radar allows the system to locate potential intruders and to control an observation area for system cameras. The multisensor construction of the system ensures significant improvement of detection probability of intruder and reduction of false alarms. A final decision from system is worked out using image data. The method of data fusion used in the system has been presented. The system is working under control of FLIR Nexus system. The Nexus offers complete technology and components to create network-based, high-end integrated systems for security and surveillance applications. Based on unique "plug and play" architecture, system provides unmatched flexibility and simplistic integration of sensors and devices in TCP/IP networks. Using a graphical user interface it is possible to control sensors and monitor streaming video and other data over the network, visualize the results of data fusion process and obtain detailed information about detected intruders over a digital map. System provides high-level applications and operator workload reduction with features such as sensor to sensor cueing from detection devices, automatic e-mail notification and alarm triggering.
Validating temporal response models for an uncooled LWIR camera
The ability to accurately model the performance of un-cooled, long-wave imaging infrared detectors is becoming increasingly important as they become more viable for a range of applications. Often micro-bolometer based detectors are employed, which have a different temporal response than traditional CCD devices, affecting motion blurring characteristics. By locking the detector readout to an optical chopper with variable delay, the temporal response may be mapped. Experimental results for a commercially available camera are presented in order to fit and validate a parametric temporal response model.
Measurement of sniper infrared signatures
M. Kastek, R. Dulski, P. Trzaskawka, et al.
The paper presents some practical aspects of sniper IR signature measurements. Description of particular signatures for sniper and background in typical scenarios has been presented. We take into consideration sniper activities in open area as well as in urban environment. The measurements were made at field test ground. High precision laboratory measurements were also performed. Several infrared cameras were used during measurements to cover all measurement assumptions. Some of the cameras are measurement class devices with high accuracy and speed. The others are microbolometer cameras with FPA detector similar to those used in real commercial counter-sniper systems. The registration was made in SWIR and LWIR spectral bands simultaneously. An ultra fast visual camera was also used for visible spectra registration. Exemplary sniper IR signatures for typical situation were presented.
Mutispectral image fusion for target detection
Marom Leviner, Masha Maltz
Various different methods to perform multi-spectral image fusion have been suggested, mostly on the pixel level. However, the jury is still out on the benefits of a fused image compared to its source images. We present here a new multi-spectral image fusion method, multi-spectral segmentation fusion (MSSF), which uses a feature level processing paradigm. To test our method, we compared human observer performance in an experiment using MSSF against two established methods: Averaging and Principle Components Analysis (PCA), and against its two source bands, visible and infrared. The task that we studied was: target detection in the cluttered environment. MSSF proved superior to the other fusion methods. Based on these findings, current speculation about the circumstances in which multi-spectral image fusion in general and specific fusion methods in particular would be superior to using the original image sources can be further addressed.