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Application of CCD Technique to Stress and Strain Measurements of Metals
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作者 XING Kai,CAO Chang-nian,YANG Dong-sheng GAO Hong-wen,LIU Lin,YANG Yong-zheng (Dept.of Appl.Phys.,Northwestern Polytechnical University,Xi’an 710072,CHN) 《Semiconductor Photonics and Technology》 CAS 1999年第4期242-246,共5页
Crossed grating stuck to metal surface was used as a strain sensor in the present work, and stress as well as strain were then investigated by accurately determining the change in the position of diffraction spot befo... Crossed grating stuck to metal surface was used as a strain sensor in the present work, and stress as well as strain were then investigated by accurately determining the change in the position of diffraction spot before and after deformed. A hardware testing system for linear CCD array, data gathering and processing was therefore developed for this purpose. Experimental results showed that the system has a good accuracy and can be used to measure stress and strain of metal surface in a real-time and quantitative manner. 展开更多
关键词 Crossed Grating linear ccd array Metal Stress STRAIN
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Real-time auto-focusing technique using centroid method for space camera
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作者 匡海鹏 李朝辉 +3 位作者 刘明 刘刚 修吉宏 翟林培 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2007年第4期577-579,共3页
A real-time auto-focusing system with auto-collimation method is introduced, which is used in auto-detecting the focus of the space camera with long focus. Auto-focusing is the key technique to ensure high quality in ... A real-time auto-focusing system with auto-collimation method is introduced, which is used in auto-detecting the focus of the space camera with long focus. Auto-focusing is the key technique to ensure high quality in space imaging. It can measure and compensate the defocus caused by the change of temperature and air pressure etc. in space. To solve the problem of auto-focusing with auto-collimation method of the camera whose axis is perpendicular to the ground, it is designed that two small caliber pentagonal prisms are placed in the area of aperture suitable to the camera’s relative aperture based on the theory of auto-focusing with auto-collimation, which can replace the big caliber plane reflector used in other cameras. Using the characteristic of pentagonal prism refracting light vertically, the target slit is imaged in CCD through the two-separated lens. It transforms the detecting of the axial defocusing quantity to the landscape orientation measurement of the faculae’s position in the direction of CCD pixels. The defocusing quantity is obtained by measuring the opposite position of the two faculae on the CCD. The Centroid method is adopted to measure the position of the auto-collimation faculae. The arithmetic error is analyzed especially, and the causation is given. Experiments show that this real-time auto-focusing system using centroid method is reliable and the focusing precision can reach ±0.01 mm. 展开更多
关键词 AUTO-FOCUSING linear array ccd centroid method
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