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19 September 2001 Field measurements with 1574-nm imaging and scannerless eye-safe laser radar
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The development of eye-safe, imaging, scannerless laser radar systems based on gated viewing with a range of some hundred meters is difficult due to the lack of fast switchable and sufficiently sensitive detectors for NIR wavelengths. Nevertheless, one basic approach is to gate an InGaAs-FPA-camera with an electro-optical modulator (EOM) in the range of about 30ns to achieve a sufficiently high resolution of depth. In this paper, we present field measurements of a system with a Nd:YAG-OPO laser of 1574nm wavelength, 7ns pulse length, 25Hz pulse frequency, and 80mJ pulse energy. Because of the special optical behavior of the EOM in conjunction with an adapted lens design and a resolution of a 128 by 128 pixel FPA the main interest is object detection, which leads to imaging with improved system performance. The experimental data will be compared with the theoretical performance model and a second system (at a wavelength of 532nm), concerning imaging under certain weather conditions. Based on the current system design we discuss problems of contrast modulation and speckle effects leading to an outlook for improvements of the system design.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ulrich Schael and Hendrik Rothe "Field measurements with 1574-nm imaging and scannerless eye-safe laser radar", Proc. SPIE 4377, Laser Radar Technology and Applications VI, (19 September 2001);

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