This PDF file contains the front matter associated with SPIE Proceedings Volume 7113, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

HgCdTe (Mercury Cadmium Telluride / MCT) staring arrays for infrared detection demonstrate constant improvements regarding their compactness and performances. Among the new detectors, the family of 15 µm pixel pitch detectors is offering a mid-TV format (384 × 288), a TV format (640 × 512) and a HD-TV format (1280 × 1024). The latest development dealing with the mid-TV format is performed according to very challenging specifications regarding compactness and low power consumption. Thanks to recent improvements, the MCT technology allows to operate detectors at higher temperature, in order to save power consumption at system level. In parallel, the 15μm pitch enables to reach challenging density and spatial resolution. This Focal Plane Arrays (FPA) is proposed in different tactical dewars, corresponding to various systems solutions.

The high level of accumulated expertise by ULIS and CEA/LETI on uncooled microbolometers made from amorphous silicon layer enables ULIS to develop 384 × 288 (1/4 VGA) IRFPA formats with 25 μm pixel-pitch designed for high end applications. This detector ROIC design relies on the same architecture as the full TV format ROIC one (detector configuration by serial link, user defined amplifier gain, windowing capability ...). The detector package is identical as the 384 × 288 / 35 μm and 640 × 480 / 25μm ones, enabling an easier system update or less non recurrent cost for different systems developments. This paper will give results of the IRFPA characterization. NETD in the range of 30mK (f/1, 300 K, 60 Hz) and operability higher than 99.99 % are routinely achieved.

The improvement of the infrared (IR) Mercury Cadmium Telluride (MCT) detectors performances impacts the measurement constraints and these advanced detectors require new types of electro-optical tests. In this paper, the development at Sofradir of advanced electro-optical test benches and test methods are described as well as the final performances measured on the advanced MCT IR detectors.

Heat-sensitive material is one of the most essential parts of microbolometer fabrication. Vanadium oxide (VO_x) and amorphous silicon (a-Si) are widely accepted materials for commercialized focal plane arrays. Meanwhile, there are a lot of efforts for finding alternative materials having better performance, lower process cost and higher yield. In this study, reactively sputtered titanium oxide (TiO_2-δ) films were investigated for heat sensitive material. Microbolometer device was also fabricated by using the TiO_2-δ film as a heat sensitive material. It is well known that the TiO_2-δ can have several phases according to film deposition condition. Properties of TiO_2-δ film could be largely varied by controlling the deposition condition. Resistivity of the fabricated TiO_2-δ film was ranged from 10^-2 Ω•cm to 10 Ω•cm. Negative TCR(temperature coefficient of resistance) value up to 2.8 %/K was obtained. 1/f noise of the TiO_2-δ film was comparable to that of VOx film. From the fabrication result of microbolometer device, feasibility of the reactively sputtered TiO_2-δ film was demonstrated. NETD(Noise equivalent temperature difference) of the 50μm-pitch simple single-level membrane structure microbolometer was 34mK with conditions of 1V bias and 30Hz operation frequency.

We present the 3D-imaging of a target using range gated laser systems operating at 1.5 μm. Two different illumination techniques were investigated: 1) a conventional illumination technique consisting of a Raman-shifted Nd:YAG laser with a fixed wavelength, and 2) a technique which makes use of a wavelength-tunable illumination source consisting of a Nd:YAG-pumped OPO. We compare the influence of each illumination technique on target induced speckle effects and the resulting range resolution. Image samples were taken at ranges of up to 2.5 km.

Measurement of atmospheric modulation transfer function (MTF) derived from the point spread function is an alternative to the use of scintillometry in characterizing the effects of turbulence as well as optical scattering. This experiment involved measurement of the system point spread function at 630 nm wavelength, over a 1.8 km path between the shoreline and Roman Rock lighthouse, which is offshore in False Bay near Simonstown, South Africa. Four telescopes at heights between 4 m and 14 m above the sea surface were mounted at the shoreline looking at two point sources mounted at heights of 6 m and 13 m above the sea surface on the lighthouse. The telescopes were equipped with digital charge-coupled device (CCD) cameras and the system MTF of the combination was measured. While the point spread function is also sensitive to atmospheric scattering, scintillation is driven largely by turbulence. Measurements were made under a wide variety of environmental conditions and the differences between image quality metrics and scintillation metrics were examined. Local weather parameters, visibility and sea temperature were also monitored during the campaign and the impact of these parameters on image quality was assessed. Divergent trends in scintillation and image quality were encountered.

The typical human vision system is able to discriminate between a million or so different colours, yet is able to do this with a chromatic sensor array that is fundamentally based on three different receptors, sensitive to light in the blue, green and red portions of the visible spectrum. Some biological organisms have extended capabilities, providing vision in the ultra-violet, whilst others, such as some species of mantis shrimp reportedly have sixteen different types of photo-receptors. In general the biological imaging sensor takes a minimalist approach to sensing its environment, whereas current optical engineering approaches follow a 'brute' force solution where the challenge of hyperspectral imaging is addressed by various schemes for spatial and spectral dispersion of radiation across existing detector arrays. This results in a problem for others to solve in the processing and communication of the generated hypercube of data. This paper explores the parallels between some of those biological systems and the various design concepts being developed for discriminative imaging, drawing on activity supported by the UK Electro-Magnetic Remote Sensing Defence Technology Centre (EMRS DTC).

The design of modern imaging systems is intricately concerned with the control of optical aberrations. Traditionally this involves a multi-parameter optimisation of the lens optics to achieve acceptable image quality at the detector. There is increasing interest in a more generalised approach whereby digital image processing is incorporated into the design process and the performance metric to be optimised is quality of the image at the output of the image processor. We will discuss the trade offs involved in the application of this technique to low-cost imaging systems for use in the thermal infrared and visible imaging systems, showing how very useful performance enhancements can be achieved in practical systems.

Hollow optical waveguides have some unique properties compared with their solid core counterparts. These include very broad waveband, high power transmission characteristics in conjunction with extremely low interfacing and propagation losses. Such characteristics provide considerable potential for novel electro-optic and infrared devices and systems. In conjunction with discrete micro-optical components hollow waveguides have been used to demonstrate integrated circuits which are the optical analogue of the electronic PCB. The underlying physics and technology of hollow optical waveguides will be discussed in the context of a wide range of applications.

A novel CMOS pixel will be described that combines the sensitivity and speed of response at low light levels of an integrating pixel with the wide dynamic range of a logarithmic response. However, as with all pixels, the low-light sensitivity of this novel pixel is ultimately limited by the dark current that flows through the pixel in parallel with the photocurrent. Since the dark current increases rapidly with temperature, this effect is particularly important for cameras that operate in hot environments. Results are reported that show that the dark current in these novel pixels and the temperature dependence of the dark current can both be reduced by careful pixel layout. Alternatively, the user generated function that controls the response of the pixel can be changed to accommodate the dark current and significantly increase the low-light sensitivity of the pixel.

Following the development of 1^st Generation systems in the 1970s, thermal imaging has been in service with the UK armed forces for over 25 years and has proven itself to be a battle winning technology. More recently the wider accessibility to similar technologies within opposing forces has reduced the military advantage provided by these 1st Generation systems and a clear requirement has been identified by the UK MOD for thermal imaging sensors providing increased detection, recognition and identification (DRI) ranges together with a simplified logistical deployment burden and reduced through-life costs. In late 2005, the UK MOD initiated a programme known as "Albion" to develop high performance 3^rd Generation single waveband infrared detectors to meet this requirement. At the same time, under a separate programme supporting higher risk technology, a dual waveband infrared detector was also developed. The development phase of the Albion programme has now been completed and prototype detectors are now available and have been integrated into demonstration thermal imaging cameras. The Albion programme has now progressed into the second phase, incorporating both single and dual waveband devices, focussing on low rate initial production (LRIP) and qualification of the devices for military applications. All of the detectors have been fabricated using cadmium mercury telluride material (CMT), grown by metal organic vapour phase epitaxy (MOVPE) on low cost, gallium arsenide (GaAs) substrates and bump bonded to the silicon read out circuit (ROIC). This paper discusses the design features of the 3^rd Generation detectors developed in the UK together with the results obtained from the prototype devices both in the laboratory and when integrated into field deployable thermal imaging cameras.

We report on studies of avalanche multiplication in InAs APDs. A range of p-i-n and n-i-p photodiodes have been characterised with both avalanche multiplication and the accompanying excess noise being measured. By using a number of laser wavelengths the injection of optically generated carriers into the multiplication region has been varied, allowing the relative magnitude of the ionisation coefficients to be determined. The results of multiplication measurements show that, contradictory to the only other published experimental results for InAs, the electron ionisation coefficient is much greater than the hole ionisation coefficient. This large ionisation coefficient ratio should result in low excess multiplication noise for electron initiated gain, a prediction which has been confirmed by the measurement of multiplied photocurrent noise. The excess noise measured on InAs APDs was extremely low, unlike that reported for other wider bandgap III-Vs, and comparable with that measured on so called electron APDs fabricated from HgCdTe. These characteristics make InAs an interesting option for the fabrication of high sensitivity APD focal plane arrays in the III-V material system.

The InAs/GaSb Type II strained layer superlattice (SLS) is promising III-V material system for infrared (IR) devices due to the ability to engineer its bandgap between 3-30 μm and potentially have many advantages over current technologies such as high uniformity smaller leakage current due to reduced Auger recombination which are crucial for large IR focal plane arrays. However, an issue with this material system is that it relies on growth on GaSb substrates. These substrates are significantly more expensive than silicon, used for HgCdTe detectors, lower quality and are only available commercially as 3" diameters. Moreover it has to go through thinning down before it could be hybridized to readout integrated circuits. GaAs substrate is a possible alternative. We report on growth and characterisation of Type-II InAs/GaSb SLS photodiodes grown on GaAs substrates for mid-wave infrared with peak responses of 3.5 μm at 77K and 4.1 μm at 295K. Comparisons with similar structure grown on GaSb substrates show similar structural, optical and electrical characteristics. Broadening of X-ray rocking curves were observed on the structure grown on GaAs substrate. A full width half maximum (FWMH) of 25.2 arc sec. for the superlattice was observed near ~30.4 degree for the structure on GaSb substrate compared to near ~30.4 degree for structure grown on GaAs. However peak responsivity values of ~ 1.9 A/W and ~ 0.7 A/W were measured at 77K and 295K for devices grown on GaAs substrate. Room temperature responsivity suggests that these photodiodes are promising as high temperature IR detectors.

Quantum dot infrared photodetectors (QDIP) have established themselves as promising devices for detecting infrared (IR) radiation for wavelengths <20μm due to their sensitivity to normal incidence radiation and long excited carrier lifetimes. A limiting factor of QDIPs at present is their relatively small absorption volume, leading to a lower quantum efficiency and detectivity than in quantum well infrared photodetectors and mercury cadmium telluride based detectors. One means of increasing the absorption volume is to incorporate a greater number of quantum dot (QD) stacks, thereby increasing the probability of photon capture. Growth of InAs/InGaAs dot-in-a-well (DWELL) QDIPs with greater than 10 stacks is challenging due to the increased strain between layers, leading to high dark current. It is known that strain can be reduced in QDIPs by reducing the width of the InGaAs well and incorporating a second well consisting of GaAs and barriers consisting of AlGaAs. A number of InAs/InGaAs/GaAs DWELL QDIPs with 30-80 stacks have been grown, fabricated and characterised. Dark current in these layers appears to be constant at given electric field, suggesting strain does not increase significantly if the number of QD stacks is increased. IR spectral measurements show well defined peaks at 5.5μm, 6.5μm and 8.4μm. In this work a comparison between dark current, noise, gain, responsivity and detectivity in these layers is presented and compared to existing data from conventional DWELL QDIPs.

The phenomenon of polarisation causes smooth man-made objects, such as metal and glass, to have a different polarisation signature to that of natural vegetation. Therefore, polarisation has the potential to discriminate man-made objects from background clutter. Polarimetric information, combined with conventional thermal imaging, provides a powerful means of reducing false alarms in applications such as situational awareness, detection of low signature targets and disturbed earth. The paper presents results of discriminative imaging algorithms that were designed to augment polarimetric signatures. Recent results from a LWIR polarimetric imager are presented and these show the merit of discriminative imaging techniques when applied to polarimetric thermal imagers.

Benefits for the detection of difficult targets have been demonstrated for multispectral and polarimetric imagery in differing conditions. The spectral differences between target and background have been seen to provide an enhancement to target discrimination. However, false alarms can occur mainly due to spectral variations in background materials. Complimentarily, polarimetric imagery has been used to detect man made targets by exploiting the reflective characteristics of man-made objects and the suppression of background clutter; but the detection process can be limited by the geometry and nature of targets. A data gathering SWIR Multispectral-Polarimetric sensor has been built to investigate whether adding polarimetric to multispectral information decreases background induced false alarms whilst maintaining good detection statistics for low contrast targets.

Imaging devices are very attractive as sensors on modern airborne platforms and there is a continuing trend toward widespread employment of imaging either alone or in combination with complementary technologies. In the civil domain, modern silicon CCD and CMOS image sensors are becoming extremely small, so that the package size of commercial miniature cameras is becoming dominated by the image forming optics, even if the latter is only a structure supporting a pinhole. We have previously reported a biologically inspired, near IR, imaging system that offers a wide field-of-view, thanks to the use of a multi-aperture sensor based on micro-optics which can be used to observe simultaneously in different directions. In this paper we describe our recent work on the design, assembly and test of a novel, all solid state camera that exploits spherical lens technology to provide a robust, wide field-of-view camera. We have also considered active fluidic lenses that can operate in the mid infra-red in order to provide additional functionality.

There are many applications for thermal imaging systems where low weight, high performance and high durability are at a premium. These include UAV systems, future warrior programs and thermal weapon sights. Thermal imaging camera design is restricted by a number external constraints including, detector packaging, detector performance and optical design. This paper describes how, by combining the latest 25µm pitch detector technology, novel optical design and shutter-less image processing a high resolution imager a system weight of 100g can be achieved. Recently developed detectors have low mass vacuum packages, in this example a 384x288 25um un-cooled microbolometer has a weight of less than 25g. By comparison, earlier 35µm and 50 µm devices were In the region of 40g. Where cameras are used in harsh environments mechanical shutters present both a reliability issue and additional weight. The low-weight camera utilises Xti Shutter-less technology to generate high quality images without the need for any form of mechanical shutter. The resulting camera has no moving parts. Lenses for Long Wave Infrared (LWIR) Thermal imaging are typically manufactured using Germanium (Ge) elements. These lenses tend to be designed with f/1.0 apertures and as a result add significant weight to the design. Thanks to the smaller detector pitch and system sensitivity a lens has been designed with a focal length of 14.95mm at f/1.3 where the mass of the optical components is 9g. The final optical assembly, including passive athermalisation has a mass of no more than 15g.

In the last few years, consumer Graphics Processor Units (GPUs) have been evolving from fixed-function display generators into general purpose parallel computers. We have explored the potential uses and limitations of this emerging technology as a video coprocessor for real-time image processing applications such as video enhancement, tracking, video stabilisation and multi-sensor fusion. We show how a GPU can be used to implement and accelerate some of these common tasks and show our results. We also address the problem of integrating a GPU into a rugged system in order to deploy this capability into the environments encountered in many defence and security applications.

Unattended Ground Sensor (UGS) systems typically employ distributed sensor nodes utilizing seismic, magnetic or passive IR sensing modalities to alarm if activity is present. The use of an imaging component to verify sensor events is beneficial to create actionable intelligence. Integration of the ground-based images with other ISR data requires that the images contain valid activity and are appropriately formatted, such as prescribed by Standard NATO Agreement (STANAG) 4545 or the National Imagery Transmission Format, version 2.1 (NITF 2.1). Ground activity sensors suffer from false alarms due to meteorological or biological activity. The addition of imaging allows the analyst to differentiate valid threats from nuisance alarms. Images are prescreened based on target size and temperature difference relative to the background. The combination of video motion detection based on thermal imaging with seismic, magnetic or passive IR sensing modalities improves data quality through multi-phenomenon combinatorial logic. The ground-based images having a nominally vertical aspect are transformed to the horizontal geospatial domain for exploitation and correlation of UGS imagery with other ISR data and for efficient archive and retrieval purposes. The description of an UGS system utilized and solutions that were developed and implemented during an experiment to correlate and fuse IR still imagery with ground moving target information, forming real-time, actionable, coalition intelligence, are presented.

Surveillance Of Borders Coastlines And Harbours (SOBCAH ) is becoming increasingly challenging in Europe due to the expansion of new European borders coupled with the increased risks from the potential quantity and variety of terrorist activities. SOBCAH was an 18-month programme undertaken as a European Commission funded Preparatory Action in the field of Security Research (PASR) initiative to identify and demonstrate improvements in security; initially focusing on techniques to maximise the surveillance and detection effectiveness of existing sensor systems and technologies. This paper discusses the rationale in identifying the requirements, establishing a system architecture and the findings of building a security system demonstrator that underwent trials in the Port of Genoa, Italy in July 2007. It will provide an overview of the main drivers for a European-wide concept to standardise the development of enhanced border security systems. The paper will focus on techniques employed in the demonstrator to maximise the intelligence gathered from many disparate sensor sources without burdening the work load of the operators; providing enhanced situational awareness of the threat environment.

CI Systems has been involved in the development and production of in-flight boresight equipment since 1989^1,2, by pioneering the field with innovative laser-FLIR and laser-CCD alignment solutions. In addition, over the years we have developed a number of systems for use on the ground to align the various electro-optical instrumentation to a common Line of Sight (LOS) before the mission. This adjustment is very important for the success of the mission: the more accurate the alignment and its retention during the flight, the better the chance of a precise hit. In this paper we describe various systems developed and built at CI for use with EO pods mounted on aircraft, especially UAV's. The most important engineering tasks are design for small size and convenient mechano-optical interfaces for different pods allowing system compactness, low weight and easy operation. Some of the design considerations to meet these challenges will be given here.

Dual color infrared imaging systems are being developed as missile warning sensors operating within the 3μm to 5μm spectral regime. To demonstrate the sensor performance of such sensors we introduce IR test projectors which provide an optical output within the required spectral band (3µm to 5µm). A bispectral objective serves as the projection optics while also forming a part of a telescope which allows visual alignment of the projection axis with high precision, e.g. by autocollimation. A compact IR source generates the IR radiation by resistive heating with heating and decay times close to 10 ms and a large dynamic range. These characteristics are exploited for the generation of intensity sequences which simulate the IR signature of an approaching missile, accomplished by a programmable control electronics driving the IR source. Results are shown which compare the required design intensity sequence with the measured projector output intensity. As an additional design feature we have also integrated an electrically tunable Fabry-Perot filter into the test projector thus making it a tunable monochromatic IR source. This allows the measurement of the spectral sensitivity of IR sensors which is of particular importance to characterize the sensor for evaluating its performance by simulation.

Proliferation and technological progress of Mid Wave Infrared (MWIR) sensors for Missile Warning Systems (MWS)1,2 and increased sophistication of countermeasures require demanding in-flight testing. The IR sensors are becoming more sensitive for longer range of detection, the spatial resolution is improving for better target detection and identification, spectral discrimination is being introduced for lower False Alarm Rate (FAR), and the imaging frame rate is increasing for faster defensive reaction. As a result, testing a complex MWS/countermeasure system performance before deployment requires ever more realistic simulation of the threats in their natural backgrounds, and faster measurement of the radiometric output, directionality and time response of the countermeasures. In a previous paper3 we have described a system (IRTS or Infrared Threat Stimulator) we developed to test missile warning systems (MWS) mounted on an aircraft. The IRTS is placed in the field and projects a time dependent infrared beam toward the flying aircraft. The time dependent intensity of the beam simulates the infrared emittance of an approaching missile in the 3 to 5 micron spectral range as sensed by an MWS system. Now we have developed a new system based on the IRTS concept allowing the user to separately control the time profiles of two different infrared ranges independently within the 3 to 5 micron range. This is important because MWS instrumentation now has higher spectral discrimination capability in order to be more missile-specific and less prone to be confused by clutter and background signals. In this paper we describe the new dual band IRTS system and its capability (or Dual Color IRTS, DCIRTS).

In the framework of a research program a broad band lens (1.7÷5.3 μm) has been designed to be inserted in an optoelectronic system of the Italian Navy. The optoelectronic system operates over full spectral band or over one of the seven sub-bands that are selected inserting spectral filters mounted on a wheel. The optoelectronic system FOV is 20°x15°, aperture F/# 2.4 and it is optically athermalized in the range -30°÷+70° C. Color aberrations correction and athermalization was obtained by means an appropriate choice of optical materials (Cleartran, Sapphire, BaF2 and CaF2). The optical athermalization has been achieved for an all aluminum mechanical mounting. The lens mechanical mounting is quite cheap as no moving parts are present while focusing is obtained regardless the objective temperature. The optical layout is composed by five lenses. The design was driven to have a low sensitive manufacturing and mounting tolerances. A diffractive lens free solution was selected because of the unacceptable radiation losses in the higher diffractive orders due to the wide spectral band. Dedicated BBAR coatings for Sapphire and Cleartran have been developed.

We present the application of Quadri-Wave Lateral Shearing Interferometry (QWLSI), a wave front sensing technique, to characterize thermal infrared lenses for wavelengths within 8 and 14μm. Wave front sensing is not only a tool to quantify optical quality, but also to map the local (dust, scratches) or global possible defects. This method offers the crucial advantage that it yields an analyzed wave front without the use of a reference arm and consequent time consuming alignment. Moreover thanks to the acceptance of QWLSI to high numerical aperture beams, no additional optics is required. This makes lens characterization convenient and very fast. We particularly show the experimental characterization of single Germanium lens and finally present the characterization of complex optical imaging systems for high-performance infrared cameras. The analysis is made in conditions that are very close to the usual conditions of the camera use; that is to say, directly in the convergent beam and in polychromatic (black body) light.

Laser radiation may lead to permanent damage of the human eye when it is exposed to high power irradiation, especially when using magnifying optics such as binoculars, sights or periscopes. Into such an optical system we integrated a novel passive solid-state threshold-triggered Wideband Protection Filter (WPF) that blocks the transmission only if the power exceeds a certain threshold. At input powers below threshold, the filter has high transmission over the whole spectral band. However, when the input power exceeds the threshold power, transmission is decreased dramatically. We demonstrate the WPF integration within a typical optical system and the influence of system parameters on the protection capability of the filter.

High resolution inertialess beam steering systems are required for numerous applications, including laser radar, multitarget designation or active imaging. We present a 1.55μm operating continuous laser beam steering system based on the cascading of an electro-optic PMN-PT ceramic optical phased array (OPA) and of two piezoactuated microlenses arrays (MLA). The function of the single devices and the principle and the operation of the combination of both are explained. Then we describe the experimental setup which was realized and outline the test results. The MLA large angle scanner consists of two MLAs, one of which can be moved with respect to the other by piezodrivers. This setup acts as a blazed grating and thus results in a discrete beam steering. Each steering position corresponds to a multiple of 2pi phase shift between adjacent beamlets. In order to get a continuous steering, we combined the MLA scanner with an electro-optic ceramic OPA. The OPA generates the piston distribution that compensates the phase difference between adjacent beamlets of the MLAs and reconstructs a continuous wavefront. The PMN-PT OPA consists in 64 phase modulators with 210µm period and a 0.5 fill factor. The maximum required voltage corresponding to the 2π phase shift is 150 Volts at 1.55µm. The OPA is imaged on the 105μm period MLAs with a 0.5-magnification telescope. The two MLAs are in a Keplerian telescope with field lenses arrangement. The steering performances of the MLAs alone are +/-12° scan angle with 28 discrete positions. Using the combined architecture, we were able to resolve 64 angular directions between each of these 28 positions. We thus experimentally obtained a continuous steering at 1.55μm over +/-12° with an angular resolution of 0.24mrad, i.e. 1800 resolved directions, with only 64+1 control voltages.

Spectral imagers rely mainly on two techniques for collection of spectral information: gratings and interferometers. The former type needs cooling of the optics to avoid background signals which significantly limit the dynamic range of the measurement. The latter type, in its present commercial configurations, is not suitable for pushbroom operation in an airborne situation. A recent spectral imager configuration based on a shearing interferometer has been shown to be suitable for pushbroom operation^1,2 without the need for cooling the optics^2,3. In a previous paper⁴ we have described the design of a new spectral imager for the 3-5 μ range, where the interferometer is a specially designed single prism. The advantages of this interferometer configuration are: i) compact optics, ii) high S/N ratio in the 3-5 μ range with small optical collection diameter, and iii) enhanced mechanical stability. The instrument has now been constructed and has been shown to perform very closely to the planned specifications. 320x240 pixels are in the image with a spectral resolution close to 50 cm^-1 and an NESR (Noise Equivalent Spectral Radiance) of 2.5×10^-9 W/(cm².sr.cm^-1). The spectrum is calibrated in units of Watt/(steradian.cm².μ). If used in an airborne pushbroom mode it provides a swath width of 240 pixels in a ~6.9 degree transverse field of view. If used in a horizon scanning configuration, it has a vertical field of ~6.9⁰ and a horizontal field up to 300 degrees. The IFOV is 0.5 milliradians. In this paper the major performance results and some examples of measurements are given.

Multispectral visible and infrared observations of various species of whales were made in the St. Lawrence Seaway near Quebec, Canada and Papawai Point in Maui, Hawaii. The Multi-mission Adaptable Narrowband Imaging System (MANTIS) was deployed in two configurations: airborne looking down, and bluff mounted looking at low-grazing angles. An Infrared (IR) sensor was also deployed in the bluff mounted configuration. Detections of marine mammals were made with these systems of submerged mammals and surface mammals at ranges up to 8 miles. Automatic detection algorithms are being explored to detect, track and monitor the behavior of individuals and pods of whales. This effort is part of a United States Navy effort to insure that marine mammals are not injured during the testing of the US Navy's acoustic Anti-submarine Warfare (ASW) systems.

Transient multi-spectral signatures have become a basis for the development of IRST (IR Search and Track) and automatic target acquisition systems. Multi-spectral signatures must be measured in absolute physical system-independent units in order to be valid for use in system design. The required data comprise a temporal profile of the radiant intensity (or radiance) emitted by the target at the target plane in the required spectral bands. The methodology for converting electronic output signal from a multi spectral radiometer - volts - into the radiant intensity of the object is a complex procedure. In this procedure the following parameters have to be taken into account: the nature of the measured target (gray body or molecular emission spectra), the spectral filter, the detector responsivity, the frequency response and rise time and all ambient parameters such as atmospheric attenuation and solar radiance. Avoiding the correct analysis procedure, leads to erroneous data which may mislead users of multi-spectral signatures. This paper describes the appropriate methodology for multi-spectral signature measurement, analysis and factors that influence the accuracy of the resultant data.

Missile Warning Systems (MWS) have the task to identify missile threats to support timely counter measures. Key difficulty is that anything which can be detected must be considered a potential alarm at the output of the classifier. Hence, MWS must be optimized at a certain threshold on the receiver operating characteristic to trade probability of declaration against false alarm rate. To identify actual threats, two neural-network based discrimination algorithms are presented. In the first approach, measured object features from each spectral band over time are used to derive temporal features that model the temporal object behavior. These temporal features are fed into a static neural network. In the second approach, the measured object features are fed directly into a dynamic neural network which has a context layer. We present performance results of the two approaches based on simulated missile data overlaid with recorded background data.

In this research, our goal is to identify anomalous targets in hyperspectral and multispectral images; our sole starting information is that the targets are larger then a single pixel and their spectral signatures are different than the background. The algorithm is executed as follows: first, we use the Principal Component Analysis (PCA) transformation to find the Projecting the data into this subspace, we create a two-dimensional histogram. From the peaks of this histogram, a set of segments is determined. In comparison, we can alternatively segment our image using the well-known Kmeans approach. We then define the larger clusters to be background segments; each pixel in the image is then given a value based on the minimum "distance" from one of the segment averages. We use three different distance measures: the Mahalanobis distance, the Euclidian distance and the Spectral Angle Mapper (SAM). These dissimilarity measures are used to evaluate the pixels that are extremely different from all of the background clusters. The "anomalies" can be found by thresholding the results. We present the results of a field test using this algorithm; we have succeeded in reaching high detection rates while keeping a very low false alarm rate.

Without prior information about the spectral signature of the desired targets in hyper- or multi-spectral images, detection algorithms look for those pixels that deviate most strongly from the statistics of their surrounding backgrounds. If we presume that the distribution of the background signatures is multivariate Gaussian, then the most common anomaly test is the RX algorithm which is based on the Mahalanobis distance. We have implemented an anomaly detection algorithm based on Triple Concentric Sliding Windows (TCSW) to perform a local RX algorithm between the inner window and each segment that appears in the outer window. The dimension of the inner window is designed to fit the size of the desired targets; in this way, we integrate both spectral and spatial properties. When the inner window contains a random mixture of backgrounds, the score of the anomaly test is rather high because the mean of the mixture is far from each of the background components. In order to deal with these mixture situations, we develop two modified versions of the RX algorithm (ISMPRX, SMPRXMix) that take into consideration the possibility of segment mixture in the inner window. The results show significant improvement in the anomaly detection performance.

This paper addresses the problem of tracking a dim moving point target from a sequence of hyperspectral cubes. The resulting tracking algorithm is useful for many staring technologies such as the ones used in space surveillance and missile tracking applications. In these applications, the images consist of targets moving at sub-pixel velocity and noisy background consisting of evolving clutter and noise. The demand for a low false alarm rate (FAR) on one hand and a high probability of detection (PD) on the other makes the tracking a challenging task. The use of hyperspectral images should be superior to current technologies using broadband IR images due to the ability of exploiting simultaneously two target specific properties: the spectral target characteristics and the time dependent target behavior. The proposed solution consists of three stages: the first stage transforms the hyperspectral cubes into a two dimensional sequence, using known point target detection acquisition methods; the second stage involves a temporal separation of the 2D sequence into sub-sequences and the usage of a variance filter (VF) to detect the presence of targets from the temporal profile of each pixel in each group, while suppressing clutter specific influences. This stage creates a new sequence containing a target with a seemingly faster velocity; the third stage applies the Dynamic Programming Algorithm (DPA) that proves to be a very effective algorithm for the tracking of moving targets with low SNR at around pixel velocity. The system is tested on both synthetic and real data.

Detectability evaluation of objects is required for sensor range performance determination or for the assessment of camouflage effectiveness. In order to obtain a statistically sound statement the evaluation is performed in a sequential or parallel manner by different human observers analysing stored image sequences, so called "video simulation trials". These sequences are captured by high quality sensors approaching the objects of interest. The proposed method is based on the visualization in real-time of different kinds of a priori knowledge related to the object location in every image of the image sequence in order to reduce the searching process of the human observer depending on recognition task. Hence the geometric transformation of geometric information through every image of the sequence is performed by applying an automatic image registration method, planar homography. Additionally, knowledge of these geometric transformations allows new trial options and trial automation so that further experiments for the proposal of a new evaluation standard for video simulation can be performed with a statistically significant number of observers.

In many surveillance missions information from a large number of interconnected sensors must be analysed in real time. When using visual sensors like CCTV cameras, it is not uncommon that an operator simultaneously has to survey the information from as many as fifty to a hundred cameras. It is obvious that the probability that the operator finds interesting observations is quite low when surveying information from that many cameras. In this paper we evaluate two different approaches for automatically detecting anomalies in data from visual surveillance sensors. Using the approaches suggested here the system can automatically direct the operator to the cameras where some possibly interesting activities take place. The approaches include creating structures for representing data, building "normal models" by filling the structures with data for the situation at hand, and finally detecting deviations in new data. One approach allows detections based on the incorporation of a priori knowledge about the situation combined with data-driven analysis. The other approach makes as few assumptions as possible about the situation at hand and builds almost entirely on data-driven analysis. The proposed approaches are evaluated off-line using real-world data and the results shows that the approaches can be used in real-time applications to support operators in civil and military surveillance applications.

Future Intelligence, Surveillance and Reconnaissance (ISR) tasking and exploitation will be based on a "system of systems" that carries out tasking, collection, integration, interpretation, and exploitation. The vision is of a closedloop tasking-exploitation-tasking ISR information system that learns from its continuous data accumulation over multiple observations, accruing and assessing evidence to determine if further tasking is needed to resolve residual target ambiguities. That closed-loop collection of systems would provide a better ability to direct ISR sensors and fuse multisource data. Such a system, with the enormous amounts of data involved and the requirement for timeliness, will require the use of automated systems that work together efficiently under real-world conditions. This paper reviews issues that are relevant to ISR tasking, coordination, and data formatting. Procedural solutions that were developed and implemented during experimental operations to correlate and fuse full motion video with ground moving target information forming real-time, actionable, coalition intelligence, are presented.

Recently new techniques for night vision cameras are developed. So-called EMCCD cameras are able to record color information about the scene. However, in low-light situations this imagery becomes noisy. This is also the case for normal CCD cameras in dark situations or in shadowed areas. In this paper we present image enhancement techniques for noisy color imagery. The techniques are based on grey-value image enhancement techniques, in particular dynamic super-resolution reconstruction, which is used to enhance the lightness of the image, and local adaptive contrast enhancement. With the super-resolution technique the temporal noise in the lightness channel of the imagery is removed. The color information of the images is spatially filtered using the edge information of the enhanced lightness image. The result is colored output imagery with reduced temporal noise.

Along with the extending application of uncooled infrared focal panel arrays, the requirements for high quality infrared imaging are increasing continuously. The nonuniformity correction technology based on existing unary linear theoretical model has become the bottleneck of infrared imaging quality improvement. Through theoretical analysis of un-cooled infrared focal panel array photoelectric response mechanism and its imaging process, the primary influencing factors for infrared sensor response and their nonuniformity are deduced in this paper. A theoretical model of binary nonlinear nonuniformity for uncooled infrared focal panel arrays is present. The impact of surrounding temperature on sensor response is taken into account in this model. Experimental test results are given in this paper. Statistic analysis results show that this model can give reasonable prediction of the responsive curve for uncooled infrared focal panel arrays sensor in wider scene radiation and surrounding temperature range. This model describes the exact photoelectric response relationship between infrared radiation and infrared detector output signal. Furthermore, this model reflects influencing factors of nonuniformity for infrared imaging more accurate than the existing unary linear theoretical model.

This paper describes a new concept related to the bolometric micromechanical sensors for detecting far IR and THz radiation. We believe that this concept permits a low cost and ease of fabrication of large bi-dimensional array of sensors with an enhanced signal-to-noise ratio. The micromechanical sensor comprises a thermo-sensitive bi-material (multi-material) micro-cantilever beam with a selective absorber dedicated to far IR and THz radiation energy, and optical readout system based on surface plasmon resonance for detecting the bending of the micro-cantilever element. To increase the radiation detector sensitivity, the SPR phenomenon is used for cantilever deflection monitoring.

The authors have approached some system design problems to achieve an interval of spatial resolutions for different characteristics of the observed scene, in which the observation probability can vary because of the thresholds of observation conditions. The paper proposes a simple analytical model for the estimation of the observation range (on the base of an imposed value for the observation probability), starting from a Boltzmann approximation which extends the observation prediction model based on the Johnson's classic criterion. Supplementary, several real image scenes, at different known observation ranges, were acquired on PC and also some patterns at different thermal contrasts, in laboratory conditions. The results of experiments have been extended into a function similar to the initial model proposed and which depends on the thermal camera used. The observation range was modelled, not only depending of target dimension and system resolution, but by the observation probability and the difficulty degree of observation, too. The deterioration of the thermal contrast has been simulated with image processing software, by a contrast controlled degradation of image, to estimate the observation probability in different environmental conditions. By a graphic-analytical optimization one can select some spatial resolution values which assure desirable acquisition probabilities of the targets at different thermal contrast values of the scene. The observation probability was analyzed for detection, recognition and identification.

The paper presents design and principle of operation of a passive IR detector of large detection range. Significant virtue of the described PIR detector is highly efficient detection of very slowly moving or crawling people. High signal-to-noise ratio was obtained by using larger number of pyroelectric sensors or by increasing number of detection zones (channels). Larger number of pyroelectric sensors forces development of a complex optical system. The presented optical system of PIR detector consists of one lens (germanium or amtir) and mirror concentrators. The optical system ensures continuity of detection zones (no "blind" area between particular detection zones). Original electronic system for PIR detector was described in which direct current amplifiers of a signal from pyroelectric sensors were applied. Electronic system automatically reduces a voltage drift from pyroelectric sensors, thus significantly decreases low limit frequency of a conduction band of amplification channel. Together with a fulfillment of this condition, low-frequency noises enhancement is observed and next detector sensitivity diminishes. To ensure large detection ranges, a new method of signals analysis was applied. PIR detector has been equipped with a channel of RS 485 standard data transmission. For registration of measurement results, special software was developed for detector diagnostics allowing registration of signals from particular detection zones. The investigation results for various ranges of PIR detector were presented. The signals from PIR detector were shown which were caused by crawling people being at the distance of 140 meters and walking, running people being at the distance more than 200 meters.

PIR detectors used in security systems for people detection operate in far IR range (8÷14) mm. These detectors most frequently employ pyroelectric sensors. Application of a single pyroelectric sensor does not ensure distinguishing the phenomena of alarm character from, so-called, false alarms caused by, e.g., air turbulences or changes in a background temperature resulting from sun radiation. Thus, in PIR detectors, the sensors with two active elements are used (two sensors) and an alarm signal is determined on the basis of analysis of a difference (or a sum) and their output signals. Essential drawback of currently available PIR detectors is low efficiency of detection of slowly moving or crawling people. Efficiency of detection of slowly moving objects is low because radiation from such objects is close to background thermal noises. The presented signal analysis is based on determination of average moving value in three "time windows" of a defined wavelength. Moreover, a principle of "time windows" creation is given and an algorithm for determination of detection thresholds is described. In PIR detector, an adaptation detection threshold was taken following thermal changes of a background. Influence of sun radiation is taken into account in the algorithm of determination of adaptation detection threshold.

Ways to improve performance of scanning and starring types photovoltaic (PV) infrared (IR) Hg_1-xCd_xTe focal plane arrays (FPA) including Hg_1-xCd_xTe Long-Wave (LWIR) PV FPA covering spectral range from 8 to 12 μm requires comprehensive estimation of photodiode's (PD) performance depending on Hg_1-xCd_xTe material properties and operating conditions and comparing it to real data published for commercial products. Advanced Infrared Focal Plane Arrays including extended Long-Wave (LWIR) 8-14 μm operating at temperatures T_op=80-100 K can be developed with due accounting of correlation between measured and correctly calculated performance. Optimized PD with n⁺-p junction is characterized by lower dark current value than previously reported in same kind n⁺-p junction. Lowest dark current is preferable for proper multiplexing of PD arrays to Silicon Read-out Integrated Circuits (ROICs) and hence to get highest possible performance as well. Comparative analysis of LWIR PD performance at 80 K is needed also to understand ways to improve FPA useful quality. Objective of the present work was to calculate Hg_1-xCd_xTe LWIR PV FPA (λ_co equals to 9.5-10.3 μm at T_op=80 K) performance variation with doping level, absorber thickness, surface recombination rate and compare it to measured data on arrays with time-and-delay integration (TDI) mode of operation. Commercial LWIR PV FPAs are fabricated as usual on Hg_1-xCd_xTe layers grown by Liquid Phase Epitaxy (LPE).