We report on the development and field trials of an active polarimetric imager in the SWIR domain. Polarization states are controlled for both emission and analysis. Based on past experience, we focus on Orthogonal State Contrast (OSC) imaging for which two images with orthogonal polarizations are needed. An important feature of the imager is the use of two InGaAs imaging detectors mounted orthogonally on a polarization beam splitter. This allows the synchronous imaging with the two orthogonal polarizations and the real time acquisition of OSC images at video frame rate without temporal artefacts. The demonstrator has been operated during field trials with static and moving scenes. These trials were mainly aimed at the detection of man-made objects (weapons, vehicles …) in complex scenes at up to a few hundreds of meters. Along with the presentation of some example of results, we discuss different representation modes of the polarimetric information.
We present in this paper a flexible Wide Dynamic Range VGA ROIC for InGaAs SWIR imaging application.
The pixel design of this ROIC incorporates both the unique solar cell mode from NIT and also a source-follower
(SF) based direct injection linear mode. The solarcell mode operation can cover an instantaneous dynamic range
of more than 120dB in a single frame without off-chip digital NUC, while the SF mode can operation sensor in a
conventional SF linear mode but with a on-chip offset compensation. The off-chip digital KTC noise
cancellation is also possible in the SF mode. This ROIC has been designed and fabricated with a standard
0.18um 1P3M process, destinated to 640x512-pixel PDA of 15um pitch. The horizontal scanning speed is
maximum 100MHz and 80MHz guaranteed, giving more than 150 frames per second. The overall performance
of this ROIC coupled to III-VLab extended visible InGaAs PDA will be presented at the conference.
The widespread adoption of THz based applications has been hindered by the lack of a real-time, broad-band, cost-effective
THz camera with sufficient sensitivity to enable applications in markets as diverse as security, non-destructive
evaluation, and biomedical imaging. This technological gap can be filled through the development of an 80 x 64 pixel
array of Sb-heterostructure backward diodes (Sb-HBDs) monolithically integrated to broadband (600 GHz - 1200 GHz)
antennas that can be directly flip-chipped to a CMOS voltage-mode readout integrated circuit (ROIC). This paper
outlines the current progress of the project.
Uncooled infrared focal plane arrays are being developed for a wide range of thermal imaging applications. CEA/LETI developments are focused on the improvement of their sensitivity enabling the possibility to reduce the pixel pitch and the decrease of the system cost by using smaller optics. We present the characterization of a 160 x 120 infrared focal plane array with a pixel pitch of 35 μm. The amorphous silicon based technology is using recent process enhancement developed by CEA/LETI and transferred to ULIS. ULIS developed for this device a low cost package. The readout integrated circuit structure is using an advanced skimming function to enhance the pixel signal exploitation. This device is well adapted to high volume infrared imaging applications where spatial resolution (in term of pixel number) is less important than cost. The electro-optical characterization is presented. Besides, a unique and high precision molding technology has been developed by Umicore IR Glass to produce low cost chalcogenide infrared glass lenses with a high performance level. Spherical, aspherical and asphero-diffractive lenses have been manufactured with very accurate surface precision. The performances are comparable to those of an optic made with aspherical germanium. This new glass named GASIR offers an alternative solution to germanium for thermal imaging, especially for medium and high volumes applications. These two key technologies are well adapted to develop infrared driver vision enhancement (DVE) system for commercial application. A European project named ICAR has been setting up to exploit these advantages. An overview of the project will be given.
Uncooled infrared focal plane arrays are being developed for a wide range of thermal imaging applications. CEA / LETI developments are focused on the improvement of their sensitivity enabling the possibility to reduce the pixel pitch in order to decrease the total system cost by using smaller optics. We present the characterization of a 160 x 120 infrared focal plane array with a pixel pitch of 35 μm. The amorphous silicon based technology is the latest one developed by CEA / LETI and transferred to ULIS. ULIS developed for this device a low cost package based on existing technologies. The readout integrated circuit structure is using an advanced skimming function to enhance the pixel signal exploitation. This device is well adapted to high volume infrared imaging applications where spatial resolution is less important than device cost. The electro-optical characterization is presented. Besides, A unique and high precision molding technology has been developed by Umicore IR Glass to produce low cost chalcogenide infrared glass lenses with a high performance level. Spherical, aspherical and asphero-diffractive lenses have been manufactured with very accurate surface precision. The performances are comparable to those of an optic made with aspherical germanium. This new glass named GASIR2 offers an alternative solution to germanium for thermal imaging, especially for medium and high volumes applications. These two key technologies are well adapted to develop infrared enhanced driver vision (EDV) system for commercial application. A European project named ICAR has been setting up to exploit these advantages. An overview of the project will be given.
This paper aims to illustrate the advantages of Lock-In Thermography (LIT) as a non-destructive, real time and non- contact technique to analyze and to locate thermo-mechanical mechanisms in materials and structures. Due to the first and second principles of thermodynamics, there is a relationship between temperature and mechanical behavior laws. LIT is classically used to measure linear thermo-elastic effect to evaluate stresses in structures under periodic, random or transient loading. The new digital processing D-MODE presented allows extracting non-linear coupled thermo-mechanical effects (dissipated energy) cycle by cycle during a fatigue test on specimens and on real structures. This quantity much smaller than thermo-elastic source needs a high sensitive thermal imaging camera and a dedicated algorithm to separate dissipated energy from thermo-elastic source. On the other hand, it has been known for a long time that there is a correlation between plasticity in materials and the appearance of heat dissipation. More recently, it was shown there is a clear relationship between fatigue limit and occurrence of dissipated energy. We propose to improve these two methods by using LIT instead of temperature rise measurement to predict crack occurrence in real structures. At last we present some industrial applications in automotive and aircraft industries.
There is a trend today towards a reduction in target signatures, the signatures becoming increasingly adapted to the background in which the targets operate. In addition, new types of countermeasures are making the task for optical seekers increasingly difficult. One way to increase the capability of detecting low-signature targets in a countermeasure environment is to utilize not only the magnitude of the signature but also its distribution over the spectrum. For collection of information regarding the spectral signatures of targets, countermeasures and backgrounds, a multispectral imaging MWIR sensor has been developed by us. This device utilizes the high frame rate made possible by modern FPA arrays. Such an array has been combined with a rapidly rotating filter wheel, thereby producing images of 128 by 128 pixels in six wavelength bands in the 2 - 5 micrometer region at a frame rate exceeding 30 Hz in each band. The sensor has a field-of-view of 3.7 degrees and a pixel resolution of 0.5 mrad. The sensor has the capability to perform two point correction in real time, thereby compensating for the different dynamic ranges in each spectral band. An extensive measurement program is in progress for gathering data for targets, countermeasures and backgrounds. Selected results from this program are presented.
KEYWORDS: Long wavelength infrared, Cameras, Staring arrays, Digital signal processing, Image quality, Thermography, Image processing, Mercury cadmium telluride, Signal processing, Control systems
CEDIP is the first company to produce commercially available LWIR cameras using HgCdTe (MCT) staring arrays. This range of thermal imagers is available in various configurations including split Stirling cooler and integrated micro machine coolers. The design of thermal imagers with this technology requires advanced signal and image processing in order to correct for array non-uniformities, thermal drift and to display the highest quality images. This paper focuses on some of the technical solutions used inside the camera such as the proprietary DSP electronic board which controls in real time the image quality parameters as well as the optical solutions and lens arrangements which provide sharp and clear images. Experimental data and obtained performances are presented and discussed.
KEYWORDS: Digital signal processing, Cameras, Analog electronics, Nonuniformity corrections, Signal processing, Imaging systems, Staring arrays, Charge-coupled devices, Sensors, Thermography
In recent years, CEDIP has designed and produced several imaging systems using MCT-FPA from SOFRADIR. From the simple 64 element linear array to the advanced 128 by 128 LWIR matrix, a large amount of expertise has been gained in the design of advanced electronic modules and optics. The purpose of this paper is to present some of the technical solutions and basic concepts defined and used by CEDIP's engineers during the design phase. Performance data about the commercially available Peltier cooled IRFPA camera, based on these design concepts, also is given.
CEDIP 13S has designed the RTIS 8902 under license of ONERA, a Pc
compatible system for the digital recording of infrared images in real time and over a large
dynamic of digitization (12 bits). The RTIS 8902 operates with AGEMA cameras, an
extension to JI1FRAMETRICS camera is currently under development The unit is able to
store to hard disk evezy infrared image from a single camera or a dual camera, the
maximum storage time is related to the hard disk capacity and is about 10 minutes for a
600 MBytes hard disic
Several applications for the RTIS 8902 have already been developed among
whose infrared signature analysis, combustion analysis and nondestructive testing of
matezials.
The present paper describes a commercially available equipment, the PTR 9000,
developped and build with the RTLS 8902 unit, and dedicated to the NDT of materials.
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