Front Matter: Volume 8540

The modelling of the Automatic Target Detection, Recognition and Identification performance in systems of multiple sensors and/or platforms is important in several respects. For example, in the selection of sensors or sensor combinations of sufficient performance to achieve operational requirements or; for understanding how the system might be best exploited. To this end a simulation framework has been developed examining sensor options across different sensor types, parameterisations, search strategies, and applications. It uses Bayesian Decision Theoretic principles, along with simple sensor models and Monte-Carlo simulation, to derive the expected performance of single deployed sensors and of sensor combinations. The basic framework has been significantly extended to include recognition and identification problems along with the detection problem for which it was originally designed. The framework has also been expanded to treat cases in which the sensors are poorly characterised, and recommendations for parameterisation in this mode are made. The sensor system modelling framework has been applied to a number of illustrative problems. These range from simple target detection problems using sensors of differing performance or of different regional search schemes, through to examinations of: the number of measurements required to reach threshold performance; the effects of sensor measurement cost; issues relating to the poor characterisation of sensors within the system, and; the performance of a more elaborate combined detection and recognition sensor system. Generally, these results tend to show that the method is able to quantify qualitative expectations of performance, and is sufficiently powerful to highlight some unexpected aspects of operation.

Coast mode is one of tracking modes that deals with the target occlusion, where tracking is halted for a while and the servo slew rate is maintained according to the target movement just before the occlusion. As the last step of the coast mode tracking, this paper presents a target re-locking algorithm to resume the target tracking after the blind time. First, during the normal image tracking stage, as a target model, a gray-level histogram ratio of the target and background is computed for each frame of the normal stage images thereby updating the target model at each time step. When entering the coast mode due to occlusion, we run the re-locking algorithm for each frame of the coast mode images so that it can immediately resume the tracking right after the end of the blind time. The re-locking algorithm divides the input image into blocks and for each block of the image, it takes an average of histogram ratios over the block and selects candidate target blocks of large histogram ratios, where the histogram ratio is evaluated at the gray-level of each pixel in the block and those histogram ratios are averaged over the pixels in the block. Due to the block-based averaging, the overall decision is robust to noise in the IR image, and the re-locking process afterward is of reduced computational complexity. With the target candidate blocks, a clustering is performed to make target candidate clusters, where each cluster is a set of connected blocks of large histogram ratios. As a final step, the first-ranked target candidate cluster is selected by computing an overall score that combines the histogram ratios and the prior knowledge of the target size, location, and variation of the intensity obtained during the normal tracking stage. We present experimental results based on both computer simulation and test under real environment with EOTS demonstrating the effectiveness of the proposed algorithm.

There are many separated infrastructural objects within a harbor area that may be considered „critical", such as gas and oil terminals or anchored naval vessels. Those objects require special protection, including security systems capable of monitoring both surface and underwater areas, because an intrusion into the protected area may be attempted using small surface vehicles (boats, kayaks, rafts, floating devices with weapons and explosives) as well as underwater ones (manned or unmanned submarines, scuba divers). The cameras used in security systems operate in several different spectral ranges in order to improve the probability of detection of incoming objects (potential threats). The cameras should then have adequate range parameters for detection, recognition and identification and those parameters, both measured and obtained through numerical simulations, will be presented in the paper. The range parameters of thermal cameras were calculated using NVTherm software package. Parameters of four observation thermal cameras were also measured on a specialized test stand at Institute of Optoelectronics, MUT. This test stand makes it also possible to test visual cameras. The parameters of five observation cameras working in the visual range were measured and on the basis of those data the detection, recognition and identification ranges were determined. The measurement results and simulation data will be compared. The evaluation of range parameters obtained for the tested camera types will define their usability in the real security system for the protection of selected critical infrastructure of a seaport.small surface objects (such as RIB boats) by a camera system and real test results in various weather conditions will also be presented.

Crystalline silicon carbide (SiC) is a wide bandgap covalent semiconductor material with excellent thermo-mechanical and optical properties. While the covalent bonding between the Si and C atoms allows n-type or p-type doping by incorporating dopant atoms into both the Si and C sites, the wide bandgap enables fabrication of optical detectors over a wide range of wavelengths. To fabricate a mid-wave infrared (MWIR) detector, an n-type 4H-SiC substrate is doped with Ga using a laser doping technique. The Ga atoms produce an acceptor level of 0.30 eV which corresponds to the MWIR wavelength of 4.21 μm. Photons of this wavelength excite electrons from the valence band to the acceptor level, thereby modifying the electron density, refractive index, and reflectance of the substrate. This change in reflectance constitutes the detector response. The dynamics of the detector response are studied by placing a chopper at a constant angular velocity between the MWIR radiation source and the detector. The imaging capability of the detector is established by reflecting incoherent light at a wavelength of 633 nm, which is produced by projecting illumination from a light-emitting diode (LED) off the detector towards a CMOS camera and examining the digital output of the camera to determine the relative intensity of the incident radiation. In addition, a mathematical model is presented to analyze the dynamic response and determine the electron density and lifetime in the acceptor level.

Zinc oxide (ZnO) provides a unique wide bandgap biocompatible material system exhibiting both semiconducting and piezoelectric properties, and is a versatile functional material that has a diverse group of growth morphologies. Bulk ZnO has a bandgap of 3.37 eV that corresponds to emissions in the solar blind ultraviolet (UV) spectral band (240-280 nm). We have grown highly ordered vertical arrays of ZnO nanowires (NWs) and nanorods using a metal organic chemical vapor deposition (MOCVD) growth process on Si(111), SiO₂, and sapphire substrates. The structural and optical properties of the grown vertically aligned ZnO nanostructure arrays were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL) measurements. The unique diffraction pattern for ZnO(002) concurred with the SEM inspection indicating vertical orientation of the NWs and nanorods. UV detectors based on ZnO NWs offer high UV sensitivity and low visible sensitivity for applications such as missile plume detection and threat warning. An analytical model that can predict sensor performance with and without gain for a desired UV band of interest has also been developed that has the potential for substantial improvements in sensor performance and reduction in size for a variety of threat warning applications. In addition, testing and characterization of photomultiplier tubes (PMTs) exposed to eight individual UV LEDs having peak wavelengths ranging from 248 nm to 370 nm has been performed to provide a relative UV detection performance benchmark. Compared to PMTs, the NW arrays are expected to exhibit low noise, extended lifetimes, high quantum efficiency, and very low power requirements.

This paper focuses on the development of a portable variable climate controlled system that can be tailored to the requirements of the item to be stored by manipulating the temperature, humidity and light levels within the controlled area. This could be used to store anything from bio-chemical samples (to preserve them from field work) to cooled electronics (prior to deployment in a given situation) to foodstuffs (such as wine and other alcohols). In this situation however, to provide a relatively simplistic example, the environment will be used to store wine. The system is adaptive in that anything can be stored within it, assuming the storage parameters are known in order to correctly configure the environment. In this paper a microcontroller (PICF4520) is connected to a fridge with various sensors attached to monitor and manipulate the environment and adjust it accordingly. For the chosen item to be stored, a temperature of 13- 14oC is required, a high humidity level and a non-Ultraviolent (UV) light source. This work thus allows for a small handheld unit that could be used to control the climate within without the need for the traditional 12 – 16 foot size portable units traditionally used. The unit could be left in the field and run off a solar cell to assist in longer term studies. This paper presents how the microcontroller is connected to the fridge and its sensors, how it manipulates the environment and the process by which the temperature and other factors can be changed without having to edit and recompile the C code, this allows for a much more friendly device interface.

The features of our Monitoring Line System ( MLS) already applied on terrestrial fiber-optic networks and its adaptation for aircraft setting are presentment in this paper. Further, the usage of the same monitoring technology as well as the digital one on monitoring of embedded fibers in the composite shell of the aircraft is explored. Embedded fiber could be used for both network, such as AIRcraft Passive Optical Network (AirPON), and for health and stress monitoring of the composite shell. Within the framework of embedded fiber in the composite shell, termination possibilities with multi-channel MT ferrules were investigated.

Free-space optics (FSO) holds the potential for high bandwidth communication in situations where landline communication is not practical, with relatively low cost and maintenance. The short-wave infrared (SWIR) and midwave infrared (MWIR) bands contain atmospheric transmission windows spanning approximately 1.50-1.75 μm and 4.6- 4.9 μm, respectively. Transmission coefficients and losses were modeled using MODTRAN for optical path lengths of up to 2 km to for various atmospheric conditions. The determination of the refractive index structure parameter C_n ² is useful in calculating the time-dependent Fried parameter, r₀, which provides an indication of the magnitude of the phase distortion of an optical wavefront by scintillation in accordance with the Kalomogorov model. By better understanding the effects of turbulence and C_n ² on FSO transmission through modeling and experimental measurements, measures can be implemented to reduce the bit error rate and increase data throughput, enabling more efficient and accurate communication links. FSO beam optimization is achievable using a Shack-Hartmann wavefront sensor, whereby wavefront distortion of a transmitted beam is measured to compensate in real time for the effects of turbulence to provide optimized FSO reception. Using advanced techniques and compensation methods, limitations associated with infrared FSO transmission and reception in the evaporation layer may be overcome or circumvented to provide high bandwidth communication through turbulence and/or adverse weather conditions.

Recently a new proposal to model the fading channel in free-space optical links, namely, the exponentiated Weibull (EW) distribution, has been made. It has been suggested that the EW distribution can model the probability density function (PDF) of the irradiance under weak-to-strong conditions in the presence of aperture averaging. Here, we carry out an analysis of probability of fade and bit error-rate (BER) performance using simulation results and experimental data. The BER analysis assumes intensity modulation/direct detection with on-off keying, and new expressions are derived. Data is modeled following the statistics of the EW fading channel model, and compared with the Gamma-Gamma and Lognormal distributions, as the most widely accepted models nowadays. It is shown how the proposed EW model is valid in all the tested conditions, and even outperforms the GG and LN distributions, that are only valid under certain scenarios.

Visible light communications (VLC) is a valuable addition to future generations of networks, utilizing light for illumination for the purposes of advanced service provisioning at high speed. Low energy consumption, license free and RF interference free operation are compelling advantages. VLC systems are affected by sunlight limiting connection availability and reliability. The paper presents an analysis of the performance of VLC systems at different locations around the world over the cycle of a year; the evaluation considers the impact of sunlight as a function of location, time and for different surfaces over the four seasons of the year.

Micro light-emitting diode (micro-LED) arrays based on an AlInGaN structure have attracted much interest recently as light sources for data communications. Visible light communication (VLC), over free space or plastic optical fibre (POF), has become a very important technique in the role of data transmission. The micro-LEDs which are reported here contain pixels ranging in diameter from 14 to 84μm and can be driven directly using a high speed probe or via complementary metal-oxide semiconductor (CMOS) technology. The CMOS arrays allow for easy, computer control of individual pixels within arrays containing up to 16×16 elements. The micro-LEDs best suited for data transmission have peak emissions of 450nm or 520nm, however various other wavelengths across the visible spectrum can also be used. Optical modulation bandwidths of over 400MHz have been achieved as well as error-free (defined as an error rate of <1x10-10) data transmission using on-off keying (OOK) non-return-to-zero (NRZ) modulation at data rates of over 500Mbit/s over free space. Also, as a step towards a more practical multi-emitter data transmitter, the frequency response of a micro-LED integrated with CMOS circuitry was measured and found to be up to 185MHz. Despite the reduction in bandwidth compared to the bare measurements using a high speed probe, a good compromise is achieved from the additional control available to select each pixel. It has been shown that modulating more than one pixel simultaneously can increase the data rate. As work continues in this area, the aim will be to further increase the data transmission rate by modulating more pixels on a single device to transmit multiple parallel data channels simultaneously.

With low radiation background of solar-blind UV and strong scattering of UV photons by atmospheric particles, UV communication can be made use of to set up a non-line-of-sight (NLOS) free-space optical communication link. Polarization modulation, besides the traditional intensity modulation, is presented to enhance the data rate of the UV communication system. The configuration and the working process of the dually modulated UV communication system with intensity modulation and polarization, the theoretical evaluation of polarization modulation, and a numerical of the scattering matrix are presented, with the conclusion that polarization modulation is achievable. By adding the polarizing devices and changing the coding procedures, the existing singly-modulated UV communication systems with intensity modulation are easily modified to be dually-modulated ones with polarization modulation and intensity modulation. Ideally speaking, the data rate of the dually-modulated UV communication system is the product of the data rate of the singly modulated system and the number of polarization modulation.

Morphological Scene Change Detection (MSCD) systems can be used to secure environments by sensing potential intruders and alerting security personnel to any security risks. To achieve this, the system compares the input from a camera to a reference image quantifying the level of change between the images, raising the alarm if this change is greater than a set triggering level. Morphological operators are than used to reduce the effect of any image change not related to a potential security risk; this includes noise and other minor changes thus decreasing the risk of false alarms. However in low light conditions MSCD systems can fail due to the reduced intensity differences between images containing security threats and reference images. This paper documents a proof of concept for a system that would use night vision images to address this problem. Here a low light scope camera attachment is used in place of a night vision camera and shows modifications to the previous MSCD system, which improves the performance when used with night vision images. The analysis of the modified system’s performance in different low light environments, this includes analysis of appropriate binary threshold and alarm triggering levels for a range of environments. The latter includes indoors at a distance, indoors at close range, outdoors at a distance and outdoors at close range. The results shown demonstrate that MSCD systems operating in low light conditions have the potential to be used as a useful tool in a security system and are compared to the original to demonstrate the improvement.

Vector analysis is a well-developed field that deals with details about line, surface and volume integrals which can be solved analytically to provide solutions to many problems. Using vector analysis, a curve can be divided up into many small arcs, each of which is a position vector. The summation of these position vectors can be used to represent the curve in detail; this is known as the total vector field. In this paper, there is shown a vector analysis methodology when applied to the wake immediately after a moving or stationary object, caused by the movement of the object through free space or the surrounding medium moving around the object respectively. The aim was to create a system that can determine the vectors between successive images in a video with the end result being able to establish an overall trajectory of the object. This could be implemented on a Field Programmable Gate Array (FPGA) or other device to be deployed in the field to track any type of object. If the device’s orientation with magnetic north-south is known, the direction of the object is travelling in can be calculated and then relayed on. This could be useful as an easily deployable warning system for the armed forces or rescue services to inform personnel of potential incoming threats. This work builds upon the Morphological Scene Change Detection (MSCD) mechanism implemented in the DSP Builder environment and describes how the changes allow the system to track the wake and plot its trajectory. System simulations of real world data are shown and the resultant imagery is then discussed. Furthermore, tests are conducted on single objects and then multiple objects to investigate how the system responds as real world situations are likely to have more than a single object.

Digital image watermarking is the process of embedding information into a digital image which may be used to verify its authenticity or the identity of its owners. This is the same as paper bearing a watermark for visible identification such as in money for example. In digital watermarking, if the signal is copied, then the information also is carried in the copy, proving that the data has been copied. In this paper, a digital watermarking approach is investigated using the DSP Builder methodology in order to provide the Morphological Scene Change Detector (MSCD) with a means by which if it detects an intruder, a watermarked copy of the triggering image is produced. This is so that if the image is required as proof in a court case; it can help show that the image has not been tampered with by means of the watermark. The system uses an 8-bit greyscale image and maps a binary watermark image onto the lowest bit level; this is then used when the MSCD is triggered. For simplicity in this case, the watermark image is the same size and the target image to be watermarked, future variations with foresee a variable watermark image size. The result will be a watermarked image that if a section is copied and pasted into another file and that file is then analysed, the watermark will be visible. The process of integrating the watermarking process into the MSCD will also be discussed as this system originally used binary images to speed up the process. Finally, this watermark system can be used with any system designed as all that is required is to insert the sub-system into a larger system meaning that it is extremely interchangeable. Keywords: Digital Watermarking, Scene Change Detection, FPGA, DSP Builder.

In this paper, we present research results carried out in EU funded project SGL for USaR (Second Generation Locator for Urban Search and Rescue Operations). The project aims to develop wireless standalone communication system with embedded sensor network, which is targeted to detect signs of life, locate victims in disaster areas and detect hazards.

The system consists of REDS (Remote Early Detection System) wireless sensor network and FIRST portable first responder device integrating 5 different victim location methods. REDS has wireless CO and CO2 sensors, a camera, vibration sensors and a sound sensor for detection of life signs. The system provides also a pointing device to locate objects on the search area. Victim positioning is possible with GPS and radio based time of flight methods. Portable and user operated FIRST device combines field chemical, audio and video measurements for early location of entrapped people, detection of buried people, air quality monitoring in confined spaces and safety and security monitoring. The system level communication is divided in two levels: sensor network level uses short range local communication and communication hubs, which use long range high level communication with operation command centre.

During the project, implemented REDS sensor network and FIRST device have been tested on a field conditions and they have proven to be robust and reliable.

The problem of difficulty in obtaining cloud-free scene at the Equatorial region from satellite platforms can be overcome by using airborne imagery. Airborne digital imagery has proved to be an effective tool for land cover studies. Airborne digital camera imageries were selected in this present study because of the airborne digital image provides higher spatial resolution data for mapping a small study area. The main objective of this study is to classify the RGB bands imageries taken from a low-altitude Cropcam UAV for land cover/use mapping over USM campus, penang Island, Malaysia. A conventional digital camera was used to capture images from an elevation of 320 meter on board on an UAV autopilot. This technique was cheaper and economical compared with other airborne studies. The artificial neural network (NN) and maximum likelihood classifier (MLC) were used to classify the digital imageries captured by using Cropcam UAV over USM campus, Penang Islands, Malaysia. The supervised classifier was chosen based on the highest overall accuracy (<80%) and Kappa statistic (<0.8). The classified land cover map was geometrically corrected to provide a geocoded map. The results produced by this study indicated that land cover features could be clearly identified and classified into a land cover map. This study indicates the use of a conventional digital camera as a sensor on board on an UAV autopilot can provide useful information for planning and development of a small area of coverage.

The presence of snipers in modern conflicts leads to high insecurity for the soldiers. In order to improve the soldier's protection against this threat, the French German Research Institute of Saint-Louis (ISL) has been conducting studies in the domain of acoustic localization of shots. Mobile antennas mounted on the soldier's helmet were initially used for real-time detection, classification and localization of sniper shots. It showed good performances in land scenarios, but also in urban scenarios if the array was in the shot corridor, meaning that the microphones first detect the direct wave and then the reflections of the Mach and muzzle waves (15% distance estimation error compared to the actual shooter array distance). Fusing data sent by multiple sensor nodes distributed on the field showed some of the limitations of the technologies that have been implemented in ISL's demonstrators. Among others, the determination of the arrays' orientation was not accurate enough, thereby degrading the performance of data fusion. Some new solutions have been developed in the past year in order to obtain better performance for data fusion. Asynchronous localization algorithms have been developed and post-processed on data measured in both free-field and urban environments with acoustic modules on the line of sight of the shooter. These results are presented in the first part of the paper. The impact of GPS position estimation error is also discussed in the article in order to evaluate the possible use of those algorithms for real-time processing using mobile acoustic nodes. In the frame of ISL's transverse project IMOTEP (IMprovement Of optical and acoustical TEchnologies for the Protection), some demonstrators are developed that will allow real-time asynchronous localization of sniper shots. An embedded detection and classification algorithm is implemented on wireless acoustic modules that send the relevant information to a central PC. Data fusion is then processed and the estimated position of the shooter is sent back to the users. A SWIR active imaging system is used for localization refinement. A built-in DSP is related to the detection/classification tasks for each acoustic module. A GPS module is used for time difference of arrival and module's position estimation. Wireless communication is supported using ZigBee technology. These acoustic modules are described in the article and first results of real-time asynchronous sniper localization using those modules are discussed.

We have proposed and investigated a novel radio-over-fiber (ROF) system transmitting low-density parity-check (LDPC) coded orthogonal frequency division multiplexing (OFDM) signals based on IEEE802.16 standard by simulation. The 10-Gb/s WiMax LDPC-coded OFDM signal using 16-QAM format modulated on each subcarrier. The proposed architecture utilizes direct detection for WiMax LDPC-coded OFDM and successfully transmitted a high capacity WiMax LDPC-coded OFDM signal over 200km SMF without any amplification.

Optical fibreless data networks P2P offer fast data transmissions with big transmittance from 1- 10 Gbps on a distance of 1- 6 km. Perfections of such networks are especially flexibility, rapid creation of communications. Sensitivity to atmospheric influences, necessity of light on sight belongs to disadvantages. Transmission through atmosphere be characterized by non-stationarity, inhomogeneity, the influences have random character. It means immediately that it is possible only with difficulty to project conclusions concerning to the measurement on one line upon fiberless line in another position. Contribution tackles a question of forming of the artificial hazy atmospheres, finding the statistical parameters of artificially created foggy atmospheres that could be reproduced to real environment. This work describes created laboratory apparatus powered with fog generator, heat source and ventilating fans, which allow in a controlled way to change the optical transmission inside the bounded space. Laser diode radiation at wavelength of 850 nm is transmitted into created space like this which is scanned with optical power meter after passing of artificially created turbulent vaporous environment. Changes in intensity of the passed lights are captured; the mean value and maximum deviation from the mean value are computed. In this way it is possible to change the reached specific attenuation in dB/km. Owing to turbulences it happens to deviations from the mean value, these abnormalities are characterized by the distribution function that describes the size of turbulences in time. By the help of ergodic theorem then it is possible to deduce that the distribution function of the foggy turbulences gained at continuous time evaluation has same history like the distribution function gained behind the same conditions in the setup in other times. It holds as well that these distribution functions are the same for variety of points in experimental space, provided there are well - kept the same conditions of turbulence creations. Contribution shows the experimental values, shapes of distribution functions, their influence on attenuation of fiberless communication lines and on achieved the transmission BER. At the present time the verification of conclusions is performed from the experimental model on outdoor connecting link working upon the distance of 1,3 km at the transmission rate of 1,25 Gbps.