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	Influence of the Choice of Reference Planes on the Determination of 2D and 3D Joint Roughness Parameters 期刊论文 OAI收割 ROCK MECHANICS AND ROCK ENGINEERING, 2021, 页码: 14 作者: Wong, Louis Ngai Yuen; Meng, Fanzhen; Zhou, Hui; Yu, Jin; Cheng, Guangtan \| 收藏 \| 浏览/下载：32/0 \| 提交时间：2021/06/18 Roughness parameter Reference plane Best fit plane Anisotropy Influence factor
	Improved method of target detection on optoelectronic hybrid joint transform correlator in cluttered scences (EI CONFERENCE) 会议论文 OAI收割 2011 3rd International Conference on Mechanical and Electronics Engineering, ICMEE 2011, September 23, 2011 - September 25, 2011, Hefei, China 作者: Yang L.; Yang L. 收藏 \| 浏览/下载：22/0 \| 提交时间：2013/03/25 A classical joint transform correlator (JTC) usually yields large correlation sidelobes as well as a large correlation peak width strong zero-order peak and low diffraction efficiency which make the detection ability of JTC lower. To overcome these difficulties firstly a joint power spectrum (JPS) subtraction technique in Fourier plane was proposed where reference image power spectrum and object image power spectrum are subtracted from the JPS before inverse Fourier-transform operation it is obvious that the modified JPS removes the zero-order term. Secondly a fringe-adjusted filter (FAF) was presented to suppress sidelobes and noises. The modified JPS is multiplied by a FAF before the inverse Fourier-transform operation to obtain the cross-correlation peak. Computer simulations demonstrated the improved method can obviously remove zero-order diffraction and effectively suppress the sidelobes and noises compared with classic JTC and then improve the detection ability for JTC. Experimental results presented the sharp correlation peak and also confirmed the method effectiveness. (2012) Trans Tech Publications Switzerland.
	Method of improving the accuracy of image motion measurement for panoramic aerial cameras (EI CONFERENCE) 会议论文 OAI收割 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology, April 26, 2010 - April 29, 2010, Dalian, China 作者: Jia P. 收藏 \| 浏览/下载：25/0 \| 提交时间：2013/03/25 To improve the accuracy of image motion measurement for panoramic aerial cameras the paper proposed a method of real-time image motion measurement based on 2D spatial correlation. An auxiliary area CCD is positioned paralleled to the main linear TDI CCD in the focal plane of the camera. For every frame of the image sequence taken by the auxiliary CCD a prediction on the displacement of the current image in the flight direction is made based on the forward image motion velocity. The current and the reference images are combined together for 2D-correlation which products an image motion vector. By decomposing the vector both the forward and pendulum-swing image motions can be determined. The demanding computational requirements for the real-time 2D-correlation are covered by a joint transform optical correlator. Simulation test results show that the accuracy is improved and the measurement error is within 0.2 pixels for input images with SNR=1 dB. 2010 Copyright SPIE - The International Society for Optical Engineering.
	Design of co-path scanning long trace profiler for measurement of X-ray space optical elements (EI CONFERENCE) 会议论文 OAI收割 6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China Shun L.; Yan G.; Wei Z.; Yang Z. 收藏 \| 浏览/下载：29/0 \| 提交时间：2013/03/25 The Long Trace Profiler (LTP) is a precision surface slope error measurement instrument used in synchrotron radiation optics for many years. By making some modifications to the LTP system we developed a co-path scanning LTP (CSLTP) system to test the cylindrical aspherical surface which used in X-ray space optics. To reduce the mistake caused by air turbulence and manufacture faults of optical elements used the CSLTP is designed with the least difference between the testing beam path and the reference beam path. Also it uses multiple-beam interference but double beam interference to reduce the width of beam fringe. This improves the position precision of the beam fringe on the image plane. 2010 SPIE.
	Thermal difference analysis and athermalization design of infrared optical system (EI CONFERENCE) 会议论文 OAI收割 Optical Design and Testing IV, October 18, 2010 - October 20, 2010, Beijing, China 作者: Zhang X. 收藏 \| 浏览/下载：32/0 \| 提交时间：2013/03/25 When infrared optical system works in a large temperature range the thermal effect of optical lens and optical tube will produce image plane shift and lead to imaging quality deterioration. In order to eliminate the thermal aberration the athermalization design principles of infrared optical system were introduced and some commonly used methods of thermal difference compensation were described. Proceeding from single lens the thermal difference caused by temperature changing was analyzed and the relationship between temperature and focus shift was obtained. Considering optical tube thermal expansion a set of equations to estimate the thermal difference of lens group was given. Finally an infrared optical imaging system that can work under the temperature range of -40C to 60C was design according to athermal technique in which a new mechanical passive temperature compensation was proposed. Through simulation the athermalization design could make imaging plane shift the smallest. The simulation results coincided with the theoretical formula and the design had reference value in engineering. 2010 Copyright SPIE - The International Society for Optical Engineering.
	Study of high precision non-contact measurement based on CCD (EI CONFERENCE) 会议论文 OAI收割 4th International Conference on Information Technology and Applications, ICITA 2007, January 15, 2007 - January 18, 2007, Harbin, China Lin L.; Yun F. 收藏 \| 浏览/下载：22/0 \| 提交时间：2013/03/25 In this paper a method that measures relatively positionrelationshipquickly and accurately between two vehicles both on a horizontal plane is introduced. When the linear CCD camera placed on the end of manipulator scans two point targets located on the other vehicle by virtue of the spatial intersection principle and trigonometry theorem the relative position relationship between the loading vehicles and launching ones can be gotten(i.e. the spatial coordinate parameters of x y z and the angle displacement ). At the same time the paper establishes that the measurement error of length is less than 1mm by analysis of thee rror analysis and the simulation of computer. The angle displacement is less than 3 which satisfies the technical requests. So the vehicle orientation and loading missiles can be both done at the shortest time. It meets the demand of centralization between the measurement and execution. Forboth automatic transshipment and spatial position relationship measurement the study is valuable. And the manipulator is measure device as well as executive one so that residual inherent error decreases according to identical reference principle. Therefore the measure precision can be improved greatly.
	Developing of in-suit long trance profiler for testing slope error of aspherical optical Elements (EI CONFERENCE) 会议论文 OAI收割 ICO20: Optical Devices and Instruments, August 21, 2005 - August 26, 2005, Changchun, China Zhou C.; Li H.; Chen C.; Zhou C.; Qian S. 收藏 \| 浏览/下载：35/0 \| 提交时间：2013/03/25 Profile error of super smooth surface of optical elements at X-ray/EUV in synchrotron radiation (SR) light beam line is described as slope error of them generally. The Long Trace Profiler (LPT) is used for testing surface slope error of SR optical elements in world generally. It is requisite to use In-suit LTP measuring surface thermal distortion of SR optical elements with high heat under high bright SR source. Authors design an In-suit LTP by means of co-path interferometer with pencil light beam. The instrument not only can be used for testing slope error of mirrors in Lab. also in situation test the distortion of mirror with high heat load at synchrotron light beam line. The device can be used to test various absolute surface figures of optical elements such as aspherieal spherical and plane. It is needless standard reference surface. It is named by LTP-III. This paper describes its basic operating principle optical system mechanical constructions DC serve motor control system array detector data acquisition system and computer system for controlling and data analysis of LTP-III. The Instrument has advantages of high accuracy low cost multifunction and wide application. Length of surface measured of optical element accuracy is 0.04 arcsec.