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	Far-field focusing of laser beam based on digital image processing techniques (EI CONFERENCE) 会议论文 OAI收割 Optoelectronic Imaging and Multimedia Technology, October 18, 2010 - October 20, 2010, Beijing, China 作者: Zhao S.; Tian Y.-Z.; Liu L.-S.; Guo J.; Zhang H.-Y. 收藏 \| 浏览/下载：28/0 \| 提交时间：2013/03/25 In order to lead the laser beam transmit in the atmosphere convergently an experiment of laser focus at the distance of 450m and 300m has been operated in the outdoor place. The actual manipulations are as follows: Firstly the laser was collimated by a beam expander then the near-parallel laser beam was transmitted with a Galileo telescope system and the distance between the concave lens and the convex lens can be tuned through a precise displacement platform so the focus of the system changed due to the tiny displacement of the concave lens. Secondly the average power of the laser spot can be measured using power meter the power is 47.67mW and the standard deviation is 0.67mW while the focal length is 450m. Thirdly the energy distribution was found through the laser beam analyzer. The spot images were saved using the beam analyzer then the saved image can be processed with Matlab software afterwards. The function named EDGE and Sobel operator was used in the pre-processing of the saved image then method of median filter was used in the course of image de-noising and 53H filter was adopted in the signal analysis. The diameter of laser spot was obtained by the method above the diameter is 5.56mm and the standard deviation is 0.24mm. The spot center excursion is 0.56mm it is 10.43% of the total diameter of the laser spot. At last the key factors of the energy dissipation in the focusing system can be summarized as follows: restriction of the diffraction limit attenuation in the atmosphere geometrical aberration of optical system and the diffraction limit and the geometrical aberration are significant in the three factors above so we can reduce the impact of the both factors during the design of optical system. The reliable referenced data of the system design can be acquired through the primary experiment research. 2010 SPIE.
	Study and calibration of azimuth effect in multi-position strap-down north seeking system (EI CONFERENCE) 会议论文 OAI收割 7th World Congress on Intelligent Control and Automation, WCICA'08, June 25, 2008 - June 27, 2008, Chongqing, China 作者: Wang Z.; Zhao J.; Wang Z. 收藏 \| 浏览/下载：11/0 \| 提交时间：2013/03/25 In order to reduce the influence of azimuth effect in multi-position strap-down north seeking system its cause of formation is studied based on the precession principle of the dynamically tuned gyro. A detecting system composed by true north prism two Leica theodolites and benchmark prism fixed in the strap-down north seeking system was designed to calibrate the azimuth effect. By two steps many measurements are gone on in every position to eliminate the random error. According to the homologous between the error and the position a sinusoid is made a fit as compensate curve after the error of twelve positions is measured. Then the azimuth effect of the arbitrary position can be corrected by the curve. The experiment result shows that the seeking north standard deviation is only 11.77 after compensation which is considerably less than the 87.75 without correction. 2008 IEEE.
	分析实验数据处理中的测量不确定度期刊论文 OAI收割分析测试技术与仪器, 2005, 卷号: 11, 期号: 2, 页码: 149-152 作者: 粱开伦; 焦天恕; 李树斌收藏 \| 浏览/下载：18/0 \| 提交时间：2016/10/27 测量不确定度测量误差标准不确定度实验标准偏差合成标准不确定度 uncertainty of measurment error of mesurment standard uncertainty experiment of standard deviation combined standard uncertainty