The first steps of laser radar are discussed with the examples from range finding and designation. The followed successes in field tests and further fast development provided their wide use. Coherent laser radar, developed almost simultaneously, tried the ideas from microwaves including chirp technology for pulse compression, and Doppler mode of operation. This latter found a unique implementation in a cruise missile. In many applications, environmental studies very strongly rely upon the lidars sensing the wind, temperature, constituents, optical parameters. Lidars are used in the atmosphere and in the sea water measurements. Imaging and mapping is an important role prescribed to ladars. One of the prospective trends in laser radar development is incorporation of range and velocity data into the image information. Deep space program, even having not come to the finish, gave a lot for 3D imaging. Gated imaging, as one of the 3D techniques, demonstrated its prospects (seeing through scattering layers) for military and security usage. Synthetic aperture laser radar, which had a long incubation period, started to show first results, at least in modeling. Coherent laser radar baptized as the optical coherence tomography, along with the position sensitive laser radar, synthetic aperture laser radar, multispectral laser radar demonstrated very pragmatic results in the micro-scale applications.

Today airborne LiDAR (Light Detection And Ranging) systems has gained acceptance as a powerful tool to rapidly collect invaluable information to assess the impact from either natural disasters, such as hurricanes, earthquakes and flooding, or human inflicted disasters such as terrorist/enemy activities. Where satellite based imagery provides an excellent tool to remotely detect changes in the environment, the LiDAR systems, being active remote sensors, provide an unsurpassed method to quantify these changes. The strength of the active laser based systems is especially evident in areas covered by occluding vegetation or in the shallow coastal zone as the laser can penetrate the vegetation or water body to unveil what is below. The purpose of this paper is to address the task to survey complex areas with help of the state-of-the-art airborne LiDAR systems and also discuss scenarios where the method is used today and where it may be used tomorrow. Regardless if it is a post-hurricane survey or a preparation stage for a landing operation in unchartered waters, it is today possible to collect, process and present a dense 3D model of the area of interest within just a few hours from deployment. By utilizing the advancement in processing power and wireless network capabilities real-time presentation would be feasible.

While a Gated-Viewing system primarily provides the intensity values of the captured laser radiation, it is also possible to determine range information in a static scenario by the sliding gates method. In this paper, we compare this method to a time-of-flight based 3-D Flash LADAR technique in terms of range accuracy under moderate and strong turbulence conditions. The first method requires several Gated-Viewing images (several laser pulses) with stepwise increased gate delay times. For a 3-D Flash LADAR system, one laser pulse is sufficient because for each pixel the range is determined by the time-of-flight method. We have combined a Gated-Viewing camera (640 × 480 pixels) as well as a 3-D Flash LADAR camera (128 × 128 pixels) with a pulsed 1.57 μm laser source. The maximal laser pulse energy was 67 mJ. We have conducted field measurements at different times of day. Two reflectance panels and a vehicle at a distance of 2 km were recorded. The plates were positioned diagonal to the line of sight with an angle of about 45 degrees in order to determine range accuracies. In addition, a laser scintillometer provided atmospheric turbulence strength along the propagation path.

This paper describes the development of a high resolution waveform recording laser scanner and presents results obtained with the system. When collecting 3-D data on small objects, high range and transverse resolution is needed. In particular, if the objects are partly occluded by sparse materials such as vegetation, multiple returns from a single laser pulse may limit the image quality. The ability to resolve multiple echoes depends mainly on the laser pulse width and the receiver bandwidth. With the purpose to achieve high range resolution for multiple returns, we have developed a high performance 3-D LIDAR, called HiPer, with a short pulse fibre laser (500 ps), fast detectors (70 ps rise time) and a 20 GS/s oscilloscope for fast sampling. HiPer can acquire the full waveform, which can be used for off-line processing. This paper will describe the LIDAR system and present some image examples. The signal processing will also be described, with some examples from the off-line processing and the benefit of using the complete waveform.

Stand-off measurements on nitromethane (NM), 2,4-DNT and 2,4,6-TNT in vapor phase using resonance Raman spectroscopy have been performed. The Raman cross sections for NM, DNT and TNT in vapor phase have been measured in the wavelength range 210-300 nm under laboratory conditions, in order to estimate how large resonance enhancement factors can be achieved for these explosives. The measurements show that the signal is greatly enhanced, up to 250.000 times for 2,4-DNT and 60.000 times for 2,4,6-TNT compared to the non-resonant signal at 532 nm. For NM the resonance enhancement enabled realistic outdoor measurements in vapor phase at 13 m distance. This all indicate a potential for resonance Raman spectroscopy as a stand-off technique for detection of vapor phase explosives.

This contribution presents the development of a lightweight, man-portable system for measuring the absolute geographic location of distant objects. The system is built entirely from COTS (Commercial Of-The-Shelf) components that are controlled using custom software and hardware solutions. It consists of a laser rangefinder, an electronic compass and inclinometer, an optical incremental encoder, a GPS receiver, a CMOS camera, an LCOS viewfinder and an FPGA module that serves as a system controller. With the use of the FPGA, low power consumption and high processing power was achieved. The user interface comprises the viewfinder and a multidirectional button. While performing measurements, the live image of the target, sensor data and calculated coordinates are displayed in the viewfinder. The measuring system also features an SD card slot for data storage and WLAN connectivity to transfer the acquired data to a geographic information system. The contribution also presents the results of field tests used to verify the system operation and Monte Carlo simulations employed to evaluate its measuring characteristics.

Onera, The French Aerospace Lab, has developed an active burst illumination imaging system with a short time gating. This imaging device is used to obtain a passive or an active image of a small volume of the illuminated scene. To better understand and evaluate the relevant physical phenomena (scintillation, speckle...) impacting on the performance on burst illumination imaging system, Onera has implemented a code (PIAF). The aim of this paper is to describe the model and to present some results. Efforts have done on 3D target geometries and surface properties. We analyze each contribution like the incoherent solar field or the incident laser field. We adapt classical and physical models for light reflection. Speckle contributions are also treated using data bases generated by an Onera tool.

We compare results issued from a numerical model that simulates the point cloud obtained by 3D laser scanning of a scene and measurements provided by a commercial laser scanner. The model takes into account the temporal and transverse characteristics of the laser pulse, the propagation through turbulent and scattering atmosphere, the interaction with the objects of the scene (which have special optical properties: BRDF...) and the characteristics of the opto-electric detection system. The model derives 4D laser imaging information as temporal laser backscattered intensity (full wave form) is considered here. Experiments and simulations are performed on targets and scenes in order to test the performances of such imager under conditions that could be representative of future applications like Sense and Avoid, Target Recognition and Mapping,...

Within the framework of the NATO group (NATO SET-132/RTG-72) on imaging ladars, a test was performed to collect simultaneous multi-mode LADAR signatures of maritime objects entering and leaving San Diego Harbor. Beside ladars, passive sensors were also employed during the test which occurred during April 2009 from Point Loma and the harbor in San Diego. This paper will report on 1.5 μm gated imaging on a number of small civilian surface vessels with the aim to present human perception experimental results and comparisons with sensor performance models developed by US Army RDECOM CERDEC NVESD. We use controlled human perception tests to measure target identification performance and compare the experimental results with model predictions.

This paper will describe ongoing work from an EDA initiated study on Active Imaging with emphasis of using multi or broadband spectral lasers and receivers. Present laser based imaging and mapping systems are mostly based on a fixed frequency lasers. On the other hand great progress has recently occurred in passive multi- and hyperspectral imaging with applications ranging from environmental monitoring and geology to mapping, military surveillance, and reconnaissance. Data bases on spectral signatures allow the possibility to discriminate between different materials in the scene. Present multi- and hyperspectral sensors mainly operate in the visible and short wavelength region (0.4-2.5 μm) and rely on the solar radiation giving shortcoming due to shadows, clouds, illumination angles and lack of night operation. Active spectral imaging however will largely overcome these difficulties by a complete control of the illumination. Active illumination enables spectral night and low-light operation beside a robust way of obtaining polarization and high resolution 2D/3D information. Recent development of broadband lasers and advanced imaging 3D focal plane arrays has led to new opportunities for advanced spectral and polarization imaging with high range resolution. Fusing the knowledge of ladar and passive spectral imaging will result in new capabilities in the field of EO-sensing to be shown in the study. We will present an overview of technology, systems and applications for active spectral imaging and propose future activities in connection with some prioritized applications.

A novel concept of an optical system for remote temperature and density measurements from aircraft is presented. The system shall monitor local air data being critical for aircraft control. The measurement method overcomes the drawbacks of conventional probes, which is mainly the vulnerability to mechanical damage caused in harsh weather conditions or e.g. by volcanic ash. The measurement system is based on LIDAR technology used to extract air temperature and density information out of the elastic and Raman backscatter, generated by scattering of a laser beam from air molecules and airborne particles. Four optimized interference filters constitute the core of the four measurement channels. The measurement method, the setup of a prototype, and first results of laboratory test measurements with a single laser pulse energy of 145 mJ at a wavelength of 532 nm are presented. The results confirm our simulations of the expected system performance. With regard to temperature measurements, the measurement precisions with current experimental settings like the central wavelengths of the rotational Raman interference filters amount 0.7 K at 1000 hPa to 2.9 K at 165 hPa for one pulse detection and 0.25 K at 1000 hPa to 1.1 K at 165 hPa for an average over 10 pulses (equal to 1 s measurement time). With regard to density measurements the corresponding errors are ranging from 0.4 % (1000 hPa) to 1.5 % (165 hPa) for one pulse detection and from 0.15 % (1000 hPa) to 0.6 % (165 hPa) for an average over 10 pulses. Further optimization is expected to reduce the required laser power and improve the precision further.

The Large Optical Test and Integration Site (LOTIS) at the Lockheed Martin Space Systems Company in Sunnyvale, CA, has successfully reached Initial Operational Capability (IOC). LOTIS is designed for the verification and testing of optical systems. The facility consists of a large, temperature stabilized vacuum chamber that also functions as a class 10k cleanroom. Within this chamber and atop an advanced vibration-isolation bench are the 6.5 meter diameter LOTIS Collimator and Scene Generator, LOTIS alignment and support equipment. IOC included completion of the entire facility as well as operation of the LOTIS collimator in air. Wavefront properties of the collimator will be described as well as facility vibration isolation properties and turbulence levels within the collimator test chamber. User-specific test capabilities will also be addressed for two major areas of concern.

Blasts and detonations release large amount of energy in short time duration. Some of this energy is released in the form of intense radiation in the whole optical spectrum. In most cases, the study of blasts is mainly based on cameras that document the event in the visible range at very high frame rates. We propose to complement this mode of blast analysis with a fast measurement of the radiation emitted by the blast at different spectral bands simultaneously. A fast multispectral radiometer that operates in the proper spectral bands provides extensive information on the physical processes that govern the blast. This information includes the time dependence of the temperature, aerosol and gas composition of the blast, as well as minute changes in the expansion of the blast - changes that may indicate the order of the detonation. This paper presents the new methodology and instrumentation of fast multispectral blast radiometry and shows analysis of measured explosions that demonstrate the power of this methodology.

More and more defence and civil applications require simulation of marine synthetic environment. Currently, the "Future Anti-Surface-Guided-Weapon" (FASGW) or "anti-navire léger" (ANL) missile needs this kind of modelling. This paper presents a set of technical enhancement of the SE-Workbench that aim at better representing the sea profile and the interaction with targets. The operational scenario variability is a key criterion: the generic geographical area (e.g. Persian Gulf, coast of Somalia,...), the type of situation (e.g. peace keeping, peace enforcement, anti-piracy, drug interdiction,...)., the objectives (political, strategic, or military objectives), the description of the mission(s) (e.g. antipiracy) and operation(s) (e.g. surveillance and reconnaissance, escort, convoying) to achieve the objectives, the type of environment (Weather, Time of day, Geography [coastlines, islands, hills/mountains]). The paper insists on several points such as the dual rendering using either ray tracing [and the GP GPU optimization] or rasterization [and GPU shaders optimization], the modelling of sea-surface based on hypertextures and shaders, the wakes modelling, the buoyancy models for targets, the interaction of coast and littoral, the dielectric infrared modelling of water material.

Along with rising concerns about the global warming and its long term consequences, the need for a better global radiative balance model increases. While the global impact of the greenhous1e trace gases is well understood, the radiative forcing of the various natural and manmade aerosols remains uncertain, especially in the IR spectral band. Studying the optical properties of large scale dust loadings in the atmosphere directly is difficult due to the vast uncertainties about their composition and size distributions. Furthermore, the chemical composition of a dust grain is linked to its size. One of the methods to bypass these inherent difficulties is to study anticipated radiative effects with a clearly defined simulant that is well characterized both chemically and by its particles size distribution. In this presentation we show results from spectral and spatial measurements of such aerosol plumes composed of silicone oil droplets. These measurements expand and improve our knowledge of the spectral signature of aerosol clouds obtained in the IR spectral band. Our previous work presented measurements carried out with a non-imaging spectro-radiometer only near the release point. In this article, we show experimental data obtained by a hypesrspectral sensor which enabled us, for the first time to perform a simultaneous measurement of an aerosol cloud, both in the spectral and the spatial domains. These results were compared to a radiative transfer model, and yielded an excellent agreement between the predicted and the measured spectral signatures. The proposed model can be used for the prediction of the optical properties of dust clouds in the atmosphere as well as assessing more accurately their impact on global climate change.

FIT3D is a Toolbox built for Matlab that aims at unifying and distributing a set of tools that will allow the researcher to obtain a complete 3D model from a set of calibrated images. In this paper we motivate and present the structure of the toolbox in a tutorial and example based approach. Given its flexibility and scope we believe that FIT3D represents an exciting opportunity for researchers that want to apply one particular method with real data without the need for extensive additional programming.

The evaluation of a country's critical infrastructure requires a detailed analysis of facilities such as airfields, harbors and heavy industry. To improve the assessment of such facilities, an assistance system for the interpretation of infrastructure facilities from aerial imagery is developed. In this paper we point out recent advances of the system's recommendation function. Besides suggesting the occurrence of undetected objects based on a probabilistic scene model and previously detected objects, the system is now able to suggest the classification of objects based on intrinsic object features and both local context (spatial relations) and global context (overall scene classification). To justify our approach the results of an experimental evaluation of the system for the classification of industrial installations is presented.

Object recognition is a typical task of aerial reconnaissance and especially in military applications, to determine the class of an unknown object on the battlefield can give valuable information on its capabilities and its threat. RecceMan® (Reconnaissance Manual) is a decision support system for object recognition developed by the Fraunhofer IOSB. It supports object recognition by automating the tedious task of matching the object features with the set of possible object classes, while leaving the assessment of features to the trained human interpreter. The quality of the features assessed by the user is influenced by several factors such as the quality of the image of the object. These factors are potential sources of error, which can lead to an incorrect classification and therefore have to be considered by the system. To address this issue, two methods for consideration of uncertainty in human feature assessment - a probabilistic and a heuristic approach - are presented and compared based on an experiment in the exemplary domain of flower recognition.

Invariant correlation filters application is the method to achieve invariance of image recognition in presence of input object distortions. Composite filter with linear phase coefficients (LPCC filter) is one of the perspective types of correlation filters. LPCCF can be realized in a scheme of optoelectronic Vander Lught's correlator as synthesized holographic filters for recognition in real time conditions. Application of binary spatial light modulators for realization of holographic LPCCF is especially interesting. Variants of "pixel to pixel" binarization methods or representation of grayscale gradation using binary "subpixel" raster can be used for binary representation of the initial hologram. The results of correlation recognition with binary amplitude holographic LPCCF application are represented in the paper.

The work is addressed to the problem of an object extraction in the images during sensor motion. In the case the object extraction requires the registration of the observed image and the reference background image. The error of the registration causes false alarms in the extraction result. In this paper the problem of object extraction during sensor motion is solved by taking into the consideration the statistical properties of this error. The solution of this problem has been obtained using the method based on Johnson distribution parameters estimation. This method has very high computational complexity; therefore, the simplified algorithm for an object extraction was developed. The experimental research results are also presented.

Up to about a decade or more ago Circular Variable Filters (CVF) were a commercial optical component useful in the visible and infrared wavelength ranges and were being produced and sold by the US company Optical Coating Laboratory, Inc. The CVF was used as a monochromator and its advantage was in its ease of use for spectroscopy especially in remote sensing applications. Based on the idea of multilayer interference coating with linearly varying thickness on the circumference of a rotating wheel, it worked as a continuously variable center-wavelength narrowbandpass filter with 1-2% spectral resolution. One spin of the wheel placed on the optical path of a light beam provided a full scan in the wavelength range and allowed a detector to record a full spectrum in that range. Since then this component was discontinued and companies used old remaining stocks from previous production batches. CI is now reconstructing the technology to be able to produce the CVF again and is building new radiometers for new applications based on it. In this paper we review the history of the CVF and its use by CI and we provide some details on the characteristics of the CVF as planned and as preliminarily tested.

An ongoing public-private research partnership has demonstrated a three-dimensional (3D) volumetric display system that incorporates a static image space. The 3D display system uses micro-electro-mechanical systems (MEMS) based mirror arrays to direct infrared light beams into an image space that exhibits two-step, twofrequency upconversion. A number of candidate image space materials have been evaluated, with 2%Er: NYF₄ appearing to be most promising at this stage of the research. In this paper, the authors build upon prior work by investigating the response time of 2%Er:NYF4. In addition, a new technique for reducing flicker in the 3D images is described. The technique includes interlacing the 3D image slices in a way similar to the interlacing that occurs in the generation of television images. Adopting this technique has the potential to reduce the flicker that is presently evident, thereby improving the overall 3D image quality.

High Power Laser Diodes (HPLD) are increasingly used in different fields of applications such as Industry, Medical and Defense. Significant improvements of performances (especially in efficiency) and a reproducible manufacturing process have led to reliable, highly robust components. For defense and security applications these devices are used predominantly for pumping of solid state lasers (range finders, designators and countermeasures) but also as direct light source (illuminator, pointer,...). For these applications the devices not only have to show outstanding electro optical performances but the packaging must also be robust enough to sustain the harsh environmental requirements. Due to recent progress in both semiconductor technology and packaging, QLD was able to push the peak power up to 400W per bar at 808nm. At this wavelength QLD has achieved record high efficiencies close to 65% in production. Thanks to a very small bar to bar pitch down to 330μm our stacks deliver peak power densities as high as 12 kW/cm². Even at 400 μm pitch the bars can be collimated in order to improve the beam quality.

The paper introduces the structure of Cs₂Te ultraviolet image intensifier. The manufacturing procedure is introduced briefly, include the procedure of front group and back group. Its spectral response characteristic is measured with a specially designed spectral response measuring system, the quantum efficiency is calculated, the diffusing length of the minor carriers is analyzed. Some other parameters are tested with testing devices. At last some opinions are brought to improve the technique.

The Reststrahlen effect has been investigated for detecting regions of recently disturbed earth, by taking images where metallic objects had been buried in a sandy soil and comparing with images of undisturbed soil. The images were taken with a Long wave Infrared (LWIR) Hyperspectral Sensor, the Hyper-Cam.

Acousto Optic Tunable Filters (AOTFs) are solid-state, electronically addressable random-access optical pass-band filters, they are also inherently polarisation-selective. Devices with apertures larger than 10mm×10mm suitable for imaging applications are now routinely manufactured. The access time of less than 20μs gives rise to operational speeds significantly faster than is achievable with alternative technologies. These factors can be exploited to realise a polarimetric spectral-imaging system capable of flexible operation at high-speed. Additionally the band-sequential operation with the ability of random access can further increase the operational speed since it is not necessary to sweep continuously across the spectrum and so acquire unwanted data. The addition of further polarising components such as retardation plates further enhance the performance as a polarimeter, with the potential of acquiring the full Stokes parameters. By exploiting the undiffracted 0-order output an RGB image of the scene as viewed through a common objective may be captured, delivering a detailed real-time image to the operator. Any areas of interest identified by the HSI may be highlighted in false-colour on the display.

Hyperspectral imaging has proven its efficiency for target detection applications but the acquisition mode and the data rate are major issues when dealing with real-time detection applications. It can be useful to use snapshot spectral imagers able to acquire all the spectral channels simultaneously on a single image sensor. Such snapshot spectral imagers suffer from the lack of spectral resolution. It is then mandatory to carefully select the spectral content of the acquired image with respect to the proposed application. We present a novel approach of hyperspectral band selection for target detection which maximizes the contrast between the background and the target by proper optimization of positions and linewidths of a limited number of filters. Based on a set of tunable band-pass filters such as Fabry-Perot filters, the device should be able to adapt itself to the current scene and the target looked for. Simulations based on real hyperspectral images show that such snapshot imagers could compete well against hyperspectral imagers in terms of detection efficiency while allowing snapshot acquisition, and real-time detection.

Pushbroom hyperspectral imagers (HSIs) are being increasingly used for aerial vegetative and/or geological ground mapping¹. There is also considerable interest in using hyperspectral imagers for aerial surveillance and military targeting². The Optics and Lasers Department of the Advanced Technology Centre (ATC) of BAE Systems has been working on these problems for several years³. To this end a number of spatial and spectral detection algorithms have been developed, based on change detection, matched filtering and anomaly detection⁴. The department owns several visible (VIS) and short wave infrared (SWIR) hyperspectral cameras systems, with different resolutions, field of views, and operational speeds.

We have performed a field trial with an airborne push-broom hyperspectral sensor, making several flights over the same area and with known changes (e.g., moved vehicles) between the flights. Each flight results in a sequence of scan lines forming an image strip, and in order to detect changes between two flights, the two resulting image strips must be geometrically aligned and radiometrically corrected. The focus of this paper is the geometrical alignment, and we propose an image- and gyro-based method for geometric co-alignment (registration) of two image strips. The method is particularly useful when the sensor is not stabilized, thus reducing the need for expensive mechanical stabilization. The method works in several steps, including gyro-based rectification, global alignment using SIFT matching, and a local alignment using KLT tracking. Experimental results are shown but not quantified, as ground truth is, by the nature of the trial, lacking.