A dual-band IR camera system based on a dual-band QWIP focal plane array in 384x288x2 format was developed. The camera delivers exactly pixel-registered simultaneously acquired images and exhibits an excellent NETD of <30 mK at an integration time of less than 10 ms. It is equipped with Camera Link and Gigabit Ethernet data interface and is connected to and operated from a personal computer.
The camera is equipped with a special dual-band, dual-field-of-view lens (14.6 degree and 2.8 degree diagonal FOV). Radiometric calibration was performed for real quantitative comparison of MWIR and LWIR radiant power.
The system uses special software to extract and visualize the - often quite small - differences of MWIR and LWIR images. The software corrects and processes the images and permits to overlay them with complementary colors such that differences become apparent and can easily be perceived.
As a special feature, the system has advanced software for real-time image processing of dynamic scenes. It has an image stabilization feature which compensates for the movement of the camera sensor relative to the scene observed. It also has a powerful image registration capability for automatic stitching of live images to create large mosaic images.
The camera system was tested with different scenes and under different weather conditions. It delivers large-format sharp images which reveal a lot of details which would not be perceptible with a single-band IR camera. It permits to identify materials (e.g. glass, asphalt, slate, etc.), to distinguish sun reflections from hot objects and to visualize hot exhaust gases.
A dual-band infrared camera system based on a dual-band quantum well infrared photodetector (QWIP) has been developed for acquiring images from both the mid-wavelength (MWIR) and long-wavelength (LWIR) infrared spectral band. The system delivers exactly pixel-registered simultaneously acquired images. It has the advantage that appropriate signal and image processing permit to exploit differences in the characteristics of those bands. Thus, the camera reveals more information than a single-band camera. It helps distinguishing between targets and decoys and has the ability to defeat many IR countermeasures such as smoke, camouflage and flares. Furthermore, the system permits to identify materials (e.g. glass, asphalt, slate, etc.), to distinguish sun reflections from hot objects and to visualize hot exhaust gases.
Furthermore, dedicated software for processing and exploitation in real-time extends the application domain of the camera system. One component corrects the images and allows for overlays with complementary colors such that differences become apparent. Another software component aims at a robust estimation of transformation parameters of consecutive images in the image stream for image registration purposes. This feature stabilizes the images also under rugged conditions and it allows for the automatic stitching of the image stream to construct large mosaic images. Mosaic images facilitate the inspection of large objects and scenarios and create a better overview for human observers. In addition, image based MTI (moving target indication) also for the case of a moving camera is under development. This component aims at surveillance applications and could also be used for camouflage assessment of moving targets.
For evaluation of the possibilities and potentials of multispectral infrared imaging a filter wheel camera system was developed. The camera is designed for high speed operation permitting acquisition of subsequent MWIR spectral images in short time. Potential applications of a multispectral camera are temperature measurement, gas and fire visualisation. Some experiments were performed to validate the applicability of the camera system.
Analysis and optimization of camouflage and the development of countermeasures requires careful examination of infrared signatures in the MWIR (3 - 5 μm) and LWIR (8 - 14 μm) atmospheric windows. A dual band infrared camera system based on two FPA detectors (640 x 512 pixels) was developed for simultaneous infrared image acquisition in the MWIR and LWIR spectral range, the <i>Dual-Band FPA640 Aero "Clementine"</i>. For the camera system most recent
quantum well infrared photo detector (QWIP) and MCT technologies are utilized. The system is designed for a helicopter-borne stabilized platform. It is equipped with two f=100 mm motorized IR lenses with identical fields of view. The image data are transmitted via optical fibers from the camera system to the CompactPCI based computing
unit. The computing unit performs non-uniformity correction and digital IR video recording to hard disk drives at full 14 bit dynamic resolution. GPS data are recorded simultaneously. During flight the camera system is operated with a compact remote display and control panel on which the live images are displayed. Sophisticated software permits overlay of MWIR and LWIR images of recorded IR videos with various algorithms. The system is prepared for upgrading with a third FPA detector covering the SWIR atmospheric window in the spectral range 1.3 - 2.5 μm. In the presentation an overview of the system specifications are given. First experiences with helicopter-borne operation are reported.
Infrared cameras are sometimes not fast or sensitive enough when short events with low temperature dynamics have to be measured. Thermal imaging systems sensitive at 3micrometers - 5micrometers usually operate with integration times of 1 ms and more for room temperature scene measurements. Thus very short events with low dynamics cannot be resolved with sufficient temporal and thermal resolution. Advanced measurement techniques which make use of triggering, summing or even lock-in must be used then. We present an infrared imaging system, based on a high quantum efficiency 384x288 pixel HgCdTe FPA detector, for temperature measurements of gasoline sprays ejected out of injection nozzles for automobile motors. The temperature distribution of the gasoline jet while ejected out of a injection nozzle (the process is finished after 2 ms) is urged to be known with high accuracy at high temporal and spatial resolution. With highly advanced instrumentation we are able to measure with both high temporal and temperature resolution. The system described here helps automotive engineers to better understand and improve the combustion process in modern motors.
Conference Committee Involvement (10)
Thermosense: Thermal Infrared Applications XLII
26 April 2020 | Anaheim, California, United States
Thermosense: Thermal Infrared Applications XLI
15 April 2019 | Baltimore, Maryland, United States
Thermosense: Thermal Infrared Applications XL
16 April 2018 | Orlando, Florida, United States
Thermosense: Thermal Infrared Applications XXXIX
11 April 2017 | Anaheim, California, United States