Recent world events have highlighted that the proliferation of UAVs is bringing with it a new and rapidly increasing threat for national defense security agencies. Whilst many reported UAV incidents seem to indicate there was no terrorist intent behind them, not unreasonable assume may be long before platforms are regularly employed by terrorists or other criminal organizations. The flight characteristics these mini- micro-platforms present challenges current systems which been optimized...

Having laid down previously the foundations of multiple-wavelength range-gated active imaging (WRAI) principle in flash mode and accumulation mode, its use superimposed style for direct tracking moving objects was studied. The movement is supposed to be a transverse plane scene. Each emitted laser pulse with different wavelength visualizes object at specific time. Therefore, set allows us freeze positions recorded image according emission period. Thus, each image, trajectory can visualized...

Some stand-alone airborne systems of target reconnaissance such as a missile seeker head use range-gated laser active imaging to visualize in the scene. To center visualized zone on target, it is important know distance between system and target. However, this exact not known before detection can be only estimated. This estimated erroneous (max≈500 m) with some technological drifts (gyrometric drift, accelerometric position error, etc.). able evaluate impact estimation error illuminance...

The tomography executed with mono-wavelength active imaging systems uses the recording of several images to restore a three-dimensional (3D) scene. Thus, in order show depth scene, different color is attributed each recorded image. Therefore, 3D restoration depends on video frame rate camera. By using multiple-wavelength range-gated system, it possible scene directly single image at moment Each emitted light pulse wavelength corresponds visualized zone distance camera shutter opens just once...

Having previously reported the foundations of multiple-wavelength range-gated active imaging (WRAI) principle in juxtaposed style and superimposed style, its use combination both styles was studied. The consists restoring 3D scene directly. Each emitted light pulse with a different wavelength corresponds to visualized zone distance scene. In each is at specific moment time. By combining these two independently video frequency, it possible deduce trajectory direction object space as well...

An active imaging system in burst mode allows the duty cycle of laser pulses to be close 50%. In this configuration, a visual artifact resulting from remote zone scene can appear image desired visualized zone. Therefore, elements will create confusion with erroneous estimated distances. These misinterpretations very disturbing when determining distance target scene. order demonstrate occurrence artifacts an mode, different translated signals time domain as well atmospheric attenuation and...

Having laid the foundations of multiple-wavelength range-gated active imaging principle in flash mode a previous paper, we have been studying its use accumulation mode. Whatever mode, consists restoring 3D scene directly single image at moment recording with camera. Each emitted light pulse different wavelength corresponds to visualized zone distance scene. So each these zones is identified by wavelength. In camera shutter opens just once during emission pulses wavelengths. However, energy...

After the demonstration of occurrence visual artifacts with an active imaging system in burst mode a previous paper, analysis this phenomenon was realized. A artifact resulting from remote zone scene can appear image real visualized when duty cycle laser pulses is close to 50%, as mode. Therefore, elements will create confusion image, erroneous estimated distances. These misinterpretations be very embarrassing those attempting determine distance target scene. From modeling realized and...

A good measure for the probability to detect a sniper telescopic sight is effective bi-directional laser retro-reflection cross section. This angular (bi-directional) property of an optical device can be measured and used fist estimation its detected by active imaging. In present paper, authors give examples resolved non-resolved sensing under mono-static bi-static conditions. As result these measurements, conditions shows highest signal response in wide range.

The combined multiple-wavelength range-gated active imaging (WRAI) principle is able to determine the position of a moving object in four-dimensional space and deduce its trajectory speed independently video frequency. However, when scene size reduced objects have millimeter size, temporal values intervening on depth visualized zone cannot be further because technological limitations. To improve resolution, illumination type juxtaposed style this has been modified. Therefore, it was...

The real time acquisition of a 3D scene has been recently democratized by video game consoles. most popular approaches such as the structure-light and stereo vision are appropriate for short distances but they not well suited long measurements in range hundred meters up to few kilometers or scattering environment. In this case, flight method is more convenient limited heavy expensive hardware requirement military applications. Indeed, strong laser illumination gated intensified camera...

Having laid down previously the foundations of combined multiple-wavelength range-gated active imaging (WRAI) principle recording a moving object in four-dimensional space represented by single image, it was necessary to know if Doppler effect could appear direction radial velocity object. This is due fact that this requires emission laser pulses at certain frequency relation speed. To limits, supposed go up relativistic speeds. From theoretical approach, some temporal behaviors leading were...

Homogeneous and speckle-free laser illumination devices are the key technology for high resolution active imaging range-gated viewing systems. At ISL, a waveguide was developed to effectively reduce speckle of solid-state sources by spatial or angular diversity approach, respectively. Further, distant scene is illuminated with homogeneous rectangular top-hat profile. In present publication we give theoretical description results from ray tracing simulations experimental investigation.

The possibility of realizing time dilation and reversal events taking place in a scene by using the multiple-wavelengths range-gated active imaging (WRAI) principle superimposed style was studied. Both temporal behaviors could be analyzed as function since WRAI allows different positions object image to frozen at moments according wavelengths. As speed photons varies refraction law crossed medium, media were used intervene recorded camera. Different wavelengths select these media. By...

Single photon avalanche diode (SPAD) sensors can detect the occurrence of a single and record binary intensities, count rates or event timing with virtually no noise. This revolutionary new optical sensing concept has potential to trigger paradigm shift that will change way we talk think about sensing. In recent years, this technology made significant advances, latest offer high-resolution arrays high temporal spatial resolution. <br/> paper, present results achieved at ISL demonstrate how...

In 2019, the French-German Research Institute of Saint-Louis (ISL) is celebrating its 60th anniversary, but roots institute are going back to early end WWII when a team German scientists led by Prof. Schardin from Air Force Technical Academy (Technische Akademie der Luftwaffe) in Berlin-Gatow came Upper Rhine work for French Army. There, was working field ballistics and world-wide renowned his works high-speed physics. years, as permanent assistant eminent Professor Carl Cranz, he developed...

The combined multiple-wavelength range-gated active imaging (WRAI) principle is able to determine the position of a moving object in four-dimensional space and deduce its trajectory speed independently video frequency. By combining two wavelength categories, it determines depth objects scene with warm color category precise moment object’s cold category. Therefore, since each had ability transmit information from different wavelengths, related spectral reflectances, became interesting...

Holographic interferometry and speckle are currently used in the field of non-destructive testing. More particularly, they permit to detect defects structures by analysis their behavior under stresses. In this work we have studied possibility using these techniques for detection cracks reinforced concrete structures. We present some results with classical double-pulse holography double reference technique. also on CCD camera.

L'infrarouge thermique et l'intensification de lumière ont longtemps eu le monopole des techniques vision nuit. L'imagerie active, comme alternative à ces deux méthodes, a connu dernières années un développement considérable grâce aux progrès réalisés au niveau sources laser intensificateurs lumière. Outre ses capacités nuit, l'imagerie active permet d'améliorer la en conditions météorologiques dégradées, reconstruire 3D zone visualisée ou d'étudier nature matériaux qui constituent une scène...

One coherent processor and one incoherent processor, both including an active contour optical implementation were constructed are presented. The consists of a complete target tracking combining Joint Transform Correlator with segmentation method based on contours or "snakes". is optoelectronic multichannel that able to segment object in real image. process algorithm has been transposed optics order accelerate image processing. correlator, its version, speeds up the overall frame rate...

Buried mine detection is a very complex problem. Many types of mines contain few metallic parts, which complicates the with classical electromagnetic systems. In this work we have studied application holographic interferometry techniques to visualization seismic wave propagation. Perturbations propagation can reveal presence buried object. At first, tested follow wave. To make acquisition system more portable, also speckle technique. Results concerning both methods are shown and discussed.

A complete target tracking processor including a segmentation method based on active contours or "snakes" has been optically implemented and its behavior evaluated. The purpose of this is to darken the background in order avoid disruptive influence tracking. optical includes Joint Transform correlator (JTC) with improved performance since proposed will appear maximum details reference. very complex depends technology several photonic devices. It consists three nematic liquid crystal spatial...