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Two-Grid Based Adaptive Proper Orthogonal Decomposition Method for Time Dependent Partial Differential Equations 期刊论文  OAI收割
JOURNAL OF SCIENTIFIC COMPUTING, 2020, 卷号: 84, 期号: 3, 页码: 27
作者:  
Dai, Xiaoying;  Kuang, Xiong;  Xin, Jack
  |  收藏  |  浏览/下载:13/0  |  提交时间:2020/10/12
Small roll angle measurement based on auto-collimation and moire fringe (EI CONFERENCE) 会议论文  OAI收割
2009 International Conference on Optical Instruments and Technology - Optoelectronic Measurement Technology and Systems, October 19, 2009 - October 22, 2009, Shanghai, China
Bai X.-G.; Cai S.; Qiao Y.-F.; Dai M.
收藏  |  浏览/下载:31/0  |  提交时间:2013/03/25
A novel method for small roll angle measurement based on auto-collimation and moire fringe is presented. A right-angle prism is used as an indicator of small roll angle around the optical axis  and a CCD is used to collect moire fringes that are generated by scale grating image which is reflected by prism and index grating. Any small roll angle of the prism will change the include angle of the grating pair and meanwhile induce a change in the moire fringe period. The relationship between roll angle and period of moire fringes is established. The period data is obtained by image processing. The experimental result certifies that the principle of small angle measurement method based on auto-collimation and moire fringe is correct and feasible. The measuring error is smaller than 0.2 within 7 range compared with 0.2 autocollimator. 2009 SPIE.  
Three-dimensional angle measurement based on auto-collimation and moire fringe (EI CONFERENCE) 会议论文  OAI收割
2008 International Conference on Optical Instruments and Technology: Optoelectronic Measurement Technology and Applications, November 16, 2008 - November 19, 2008, Beijing, China
Cai S.; Liang S.; Qiao Y.-F.
收藏  |  浏览/下载:25/0  |  提交时间:2013/03/25
A method for small three-dimensional (3D) angle measurement based on auto-collimation and moire fringe is proposed and analyzed. A right-angle prism is used as the indicator of angle change. The inclined plane indicates the pitch and yaw angles and roll angle in indicated by the rib which is the intersection of two right-angle sides. Pitch and yaw angles measurement are implemented by auto-collimation based on reticule and roll angle measurement is measured based on moire fringe. Roll angle measurement is separated from pitch and yaw by using two light sources with different frequencies. Any small change of pitch and roll angles will induce the shift of the reticule image after reflecting by inclined plane. And any small roll angle will induce a change in moire fringe width that is generated by scale grating image which is reflected by the prism and index grating. The math model of this method is built up and error analysis is presented. The theoretical calculation results show that the proposed method is feasible and can achieve high accuracy. 2009 SPIE.