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6 August 2009 Solar blind UV and visible bispectral imaging detection system
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Corona discharge of high voltage lines and equipment has always been an operational and maintenance problem for electric power utilities. In addition to causing noise and radio interference problems, these luminous discharges, which result from the ionization of air around an electrode, may also indicate the presence of faulty, damaged or contaminated high voltage components. Corona can lead to the some components' premature aging and failure. Therefore, it's necessary to develop a system to identify corona discharge sources and pinpoint the offending component so that it may be replaced. The corona emission in the solar-blind ultraviolet (SBUV) region (240 - 280 nm) is much weaker but the solar background is nil. Accordingly, a beam-split scheme, including a catadioptric UV telescope, a solar-blind UV filter, an intensified-CCD (ICCD), and a visible camera, is applied in this system. The catadioptric UV telescope is especially designed in this paper. Twain reflecting spherical surfaces, composed the majority of the UV telescope, are combined with a pair of positive and negative lenses in the front, and a correction lens in the back-end. To be emphasized, all the elements' surfaces of the catadioptric telescope are spherical, so that it can be manufactured conveniently. In addition, it has a large aperture of 68 mm, with a focus length of 180mm, so as to improve the optical resolution, enhance the power of entrance pupil and elevate the sensitivity of the imaging system. A folding mirror is positioned in front of the telescope's central obscuration so that the UV and visible cameras have a common axis. In addition, the bispectral image fusion is based on digital signal processor TMS320DM642 of TI company, where the DM642 device has three configurable video port peripherals (VP0, VP1, and VP2), and each video port consists of two channels - A and B with a 5120-byte capture/display buffer that is splittable between the two channels. Therefore, DM642 has enough video ports to satisfy two video-in channels from the UV ICCD and the visible CCD, and one videoout channel for bispectral fusion. At last, an image fusion algorithm based on pixel is used in experiments, and a bispectral fused image is given clearly in this paper.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Li-gang Wu, Wei Huang, Tie-feng Xu, Rui-qin Tan, Yan Yang, and Ming-liang Tu "Solar blind UV and visible bispectral imaging detection system", Proc. SPIE 7384, International Symposium on Photoelectronic Detection and Imaging 2009: Advances in Imaging Detectors and Applications, 738424 (6 August 2009);

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