Assessing detection performance of night vision VIS/LWIR-fusionAdomeit, Uwe
doi: 10.1117/12.2533170pmid: N/A
Thermal imagers (TI) and low light imagers (LLI; e.g. Night Vision Goggles, NVG) are today’s technologies for nighttime applications. Both possess their own advantages and disadvantages. LLI typically is ineffective in dark areas whereas TI operates also in complete darkness. On the other hand, TI often does not provide enough scene details, hindering situational awareness. Hence, it is nearby to combine the systems for common use. Today such combined systems are available as so-called Fusion Goggles: a LWIR bolometer optically fused to an image intensifier based NVG. Future development will probably replace the NVG by solid-state night vision technologies enabling sophisticated image fusion. Performance assessment and modeling of fused systems is an open problem. Main reason is the strong scene and task dependency of fusion algorithms. The idea followed here is to divide the task in detection and situational awareness ones and analyze them separately. An experimental common line of sight system consisting of a LWIR-bolometer and a low light CMOS camera was set-up to do so. Its first use was detection performance assessment. A data collection of a human at different distances and positions was analyzed in a perception experiment with the two original bands and eight different fusion methods. Twenty observers participated in the experiment. Their average detection probability clearly depends on the imagery. Although the resolution in LWIR is three times worse than the visual one, the achieved detection performance is much better. This transforms in the fused imagery also, with all fusion algorithms giving better performance than the visual one. However, all fusion algorithms to a different degree decrease observer performance compared to LWIR alone. This result is in good agreement with a Graph-Based Visual Saliency image analysis. Thus, it seems possible to assess fusion performance for the detection task by saliency calculations.
Fast decay solid-state scintillators for high-speed x-ray imagingFaderl, Norbert
doi: 10.1117/12.2532017pmid: N/A
Flash X-ray radiography (FXR) is one of the electro-optical imaging methods and the most important diagnostic tool in the field of homeland security to detect explosive materials or drugs, terminal ballistics and detonation research to register and study such high-speed phenomena even under the roughest conditions like humidity, dust, smoke, debris, and metal. Physical principles of FXR technology and imaging with hard X-rays are presented. In order to take image sequences of high-velocity impacts using FXR and intensified high-speed cameras for image separation fast solid-state scintillator screens are necessary to convert the X-ray radiation into detectable visible light. The thickness of a scintillator screen is a significant parameter because there is a trade-off between the spatial resolution and the sensitivity. A low thickness means a high spatial resolution but also a lower sensitivity. In a study we investigated the influence of scintillator thickness on the FXR image quality and the emission decay of the scintillation response called decay time. Physical parameters like spatial resolution, signal-noise ratio and contrast are used to characterize image quality. High-speed sequences of FXR images at frame rates up to 50kfps of experimental investigations on the ballistic impact behavior of various protective components against projectiles and applications in the field of military and security agencies are presented. Finally, as a result of a literature study, some applications of X-ray backscatter technology in the field of homeland security and border control are shown to detect suspicious organic materials such as explosives, drugs using and landmines fast decay solid-state scintillators.
Infrared system simulation of airborne target detection on space-based platformZhu, Hanlu; Rao, Peng; Chen, Xin
doi: 10.1117/12.2532659pmid: N/A
With the continuous occurrence of aircraft crash, it is very important to realize the detection of aerial targets on the spaced-based platform. Many countries have carried out some researches in this field, but there is still no good conclusion about the methods and systems for aerial target detection. Meanwhile, the actual cost of satellite experiments is very expensive, and it is impractical to test the detection system by launching satellites several times. Therefore, the system simulation model can be used as the basis for the design of detection system. In the simulation process, combined with the optical system parameters and detector indicators, the imaging relationship between the satellite platform, the turntable and the target are calculated, and various imaging modes such as scanning and gazing are obtained according to the specific parameters of the actual application. This simulation mode directly presents the actual satellite motion, camera imaging and target motion state. And such a simulation system greatly shortens the actual design time of the system in engineering applications. It more realistically inverts the actual operating state and can obtain the detection result without the actual satellite launch. And such a simulation system can flexibly change parameters according to the actual conditions, so it can not only be applied to aerial targets detection, but also play an important role in other fields.
The development of a multi-band handheld fusion cameraHickman, Duncan L.
doi: 10.1117/12.2533044pmid: N/A
A longwave infrared (LWIR) handheld surveillance camera has been modified through the addition of a second sensor which provides both visible (RGB) and near-infrared (NIR) image streams. The challenges and constraints imposed on the development process of this Handheld Fusion Camera (HHFC) are described, and the approach to the dual and tri-band image fusion processing schemes is presented. The physical characteristics of the existing camera acted as a major constraint on the HHFC design with the Size, Weight, and Power (SWaP) requirements restricting the choice of both the additional sensor as well as the processor engine available within the camera. The primary use of the HHFC is in groundbased security and surveillance operations which is challenging in terms of variability in the scene content. Establishing an effective processing architecture is critical to both image interpretability by the user, and operational effectiveness. The HHFC allows the user to view different image streams including enhanced single-band image data as well as both dual and tri-band fused imagery. Such flexibility allows the user to select the best imagery for their immediate requirements. Power consumption and latency figures have been minimised by the use of relatively simple arithmetical fusion algorithms combined with an Adaptive Weight Map (AWM) for regional-based optimisation. In practice, the potential performance gain achieved is necessarily limited by the required performance robustness, and this trade-off was critical to the HHFC design and the final image processing solution.
The project SPIDVE: study on EO Sensors Performance Improvement in Degraded Visual EnvironmentBarani, Gianni; Uda, Gianni; Rossi, Alessandro; Greco, Mario; Viti, Jacopo; Toci, Guido; Patrizi, Barbara; Vannini, Matteo; Masini, Andrea
doi: 10.1117/12.2532759pmid: N/A
In the last years, there has been a huge improvement in Electro-Optical (EO) systems effectiveness, due to the availability of large staring arrays detectors with higher performance, as well as strong processing capability. So both in homeland surveillance and for military situational awareness, the use of EO systems, operating from Visible to Infrared, has dramatically grown. Operations in Degraded Visual Environment (DVE) are frequent during military actions, due to many factors: either natural (poor light, fog, glare etc.) or intentionally produced (smoke, dust etc.). In these conditions the performance of EO sensors is degraded and therefore their effectiveness for Detection, Recognition and Identification (DRI) and Navigation capability. In general, the situational awareness is strongly affected as well as the safety of personnel. Proper techniques are needed to restore (at least partially) the imaging capabilities of EO sensors in DVEs. The project SPIDVE (Study on EO Sensors Performance Improvement in Degraded Visual Environment), promoted by the European Defense Agency (EDA), is focused on the analysis of the impact on EO sensors performance by the adverse visual conditions. It starts from the analysis of the status of the art in terms of technology, processing, measurements and modeling methodologies, based on the existing scientific literature, to carry out an assessment of the most promising technologies for image enhancement and restoration in different DVEs. Particular care is devoted to the discussion with the final users (the military personnel) to identify the cases of higher interest for their operations. On this basis the possible candidate methodologies shall be analyzed more deeply, evaluating their performance with the aim of selecting the most promising one. At the end, a possible roadmap for new initiatives to exploit and develop the findings shall be defined.
Influence of phosphor screen color on performance with modern night vision gogglesWeinand, Frank S.; Rommel, Sven
doi: 10.1117/12.2532485pmid: N/A
Modern Image Intensifier (I²) feature green or white phosphor screens and both types are in use in Night Vision Goggles (NVG). It is still an open question if the phosphor screen color influences operational performance. In this study, a test close to an operational task was used to assess this. Forty-nine soldiers of the German army had to perform a gunfighting course in different illumination settings. All soldiers possessed a visual acuity of LogMAR 0.1 or better and stereoscopic vision of at least 40 second of arc. Their task was to place 3 to 5 shots from four different positions on a target chart. Each soldier had to complete the course without NVG in daylight illumination conditions and in night illumination level with NVG using green and white phosphor I². The usage was in random order with roughly on third starting with one of each conditions to average the learning effect. Performance analyses included time needed to complete the course (pass-through time) and the accuracy of the shots (hit rate). Additionally, the soldiers gave a self-assessment of their performance for comparison with the objective results. The analysis of the shooting accuracy showed the homogeneity of the subject group. In mean three shots were placed in an area of 3.66 cm x 3.66 cm (SD: 2.35 cm²) regardless of the tasks, phosphor color or the position in the course. The accuracy of the fire using NVG were regardless of the phosphor color high significantly better (p = 0.00034 green resp. p = 0.00014 white) than in daylight conditions. However, the use of the aiming laser equipment attributes probably for this and it is not a true performance criterion. No significant difference was found between the three groups in the passthrough time (p = 0.89). As well no difference was found in respect of the accuracy of fire between the different screen color of the NVGs (p = 0.56). The soldiers self-assessment revealed with high significance (p = 0.001) a preference to the NVG with the white phosphorus screen. The soldiers probably prefer white phosphor because it looks closer to daylight. In contrast to this subjective preference, no significant objective performance differences appeared when using NVG with either white or green I² phosphor.
Feedback control method for limiting interfering Gaussian beams in a bistatic substance-on-surface chemical recognizerFauconier, Richard
doi: 10.1117/12.2533051pmid: N/A
In a previous paper, the use of a bistatic optical instrument for substance-on-surface chemical recognition was introduced. The apparatus proposed showed that the bistatic arrangement of multiwavelength emitter and sensor potentially allow certain unknown optical properties of the interrogated chemical (on a supporting surface) to be measured in real time. These optical variables have long plagued the results of monostatic infrared chemical recognisers with ambiguity, by virtue of being unknown and difficult to measure in real time outside of a controlled laboratory setting—(1) unknown optical properties of the supporting surface beneath the chemical layer, (2) unknown thickness and refractive index of the chemical film and (3) unknown angles of incidence and detection. It was previously shown that it is possible (and essential) to limit to a single pair, the number of narrow laser beams reaching the bistatic apparatus’s detector from its emitter, after the beams have impinged on and propagated through the interrogated substance. In this paper, a mechanism and feedbackcontrol method are discussed to accomplish two tasks: (1) limit the number of narrow beams reaching the detector from the emitter to two, and (2) determine the separation between the resulting pair of beams in real time. The beam separation is a real-time variable that is essential to determining the thickness of the unknown substance in the field, thereby removing one cause of false substance identification. The beams discussed are narrow Gaussian beams that are frequency-modulated. A generic movable variable aperture apparatus device is described that, when controlled via feedback, can position its aperture and set it to the appropriate sizes so as to exclude multiple reflections of the incident interrogating beam and thereby limit to two, the number of beams entering the detector. The feedback control system is also described with an appropriate set of state-space equations and a prototype for a robust feedback control methodology.
Radiation-induced degradation of optoelectronic sensorsInguimbert, C.; Nuns, T.; Hervé, D.; Vriet, A.; Barbero, J.; Moreno, J.; Nedelcu, A.; Ducret, S.; Saint-Pé, O.; Larnaudie, F.; Gilard, O.; Aicardi, C.
doi: 10.1117/12.2532289pmid: N/A
Space system undergo particularly hard natural radiation environment, but can also potentially be subject to the radiations injected in low earth orbit by the explosion of a nuclear weapons. The increasing use of optoelectronic components in space systems makes the risk assessment regarding the radiation effects of an increasing interest. This paper presents recent results about the degradation of optoelectronic devices in term of atomic displacements. This paper Most of this work has been developed under the EDA contract JIP-ICET2 A-1341-RT-GP within the CapTech Technologies for Components and Modules’ (TCM) in EDA. (Tracking #: SD102-11)
Data collection and preliminary results on turbulence characterisation and mitigation techniquesVelluet, M. -T.; Bell, C.; Daigle, J. -F.; Dijk, J.; Gladysz, S.; Kanaev, A.; Lambert, A.; Lemaster, D.; Potvin, G.; Vorontsov, M.
doi: 10.1117/12.2533821pmid: N/A
In the framework of NATO task group SET 226 on turbulence mitigation techniques for OA systems, a trial was conducted in the premises of RDDC-Valcartier, using indoor and outdoor facilities in September 2016. Images data sets were collected under various turbulence conditions, both controllable (indoor) and natural (outdoor). The imagery of this trial was used in the Grand Challenge, where different experts were asked to process identical input data with state-of-the-art algorithms. The trial also provided a data-base to validate theoretical and numerical models. The paper will give an overview of the experiment set-up (target, sensors, turbulence screens generators…) and present some preliminary results obtained with the collected data in terms of effectiveness of image processing techniques, new methods for turbulence characterisation, modelling of laser beam propagation.
Architectures for radiofrequency and optronics sensors onboard Remotely Piloted Aerial Systems (RPAS)Jimenez, Adrián; Alfageme, Miguel; Llamazares, David; Polo, Valentín; Simón, Santiago; Pérez García, Elisabeth
doi: 10.1117/12.2531347pmid: N/A
This work has been developed under the EDA contract no 16.ESI.OP.137 within the Electro Optical Sensors technologies Captech in EDA. In the Defence domain, the different assets are increasingly required to operate in a multirole, multi-purpose manner within a wide range of possible missions, locations and operational environments. The sensors systems, both Radiofrequency (RF) and Electro-optic (EO), are in continuous development, and the next generation will be developed with multifunctional capabilities and increased performance, therefore new architectures should be define to handle this and to combine the information offered by them in the most effective way. This will provide the capability of operation in all weather, all time, difficult conditions with a broad range of threats immersed in strong clutter and electromagnetic interference (EMI) environments and the possibility to quickly adapt to each mission scenarios. The main goal is the definition of an Interoperable, Modular, Open and Scalable architecture (IMOSA) to achieve interoperability within payloads –mainly EO and RF sensors- for Class I Remotely Piloted Aircraft Systems (RPAS) which can also be applied to Class II RPAS. The implementation of this architecture allows that a single RPAS will be able to carry a variety of sensors on-board, regardless of its manufacturer, including the maximization of sensor data fusion performance, enhancing the RPAS capabilities in hostile environments and the improvement in the payload sensors interoperability and integration properties together with a higher reliability, flexibility and a lower product life - cycle costs for both, manufacturers and final users. This study includes a review of the state of the art of the related technologies, the definition of scenarios, requirements and business cases to justify its implementation, the definition of an architecture and BB initially designed and the generation of a roadmap to implement this concept successfully in the next years. During the process, a Systems Engineering methodology based on TOGAF and NAFv3 was applied.