1. School of Instrumentation Science and Opto-electronics Engineering, Beihang University, Beijing 100191, China
2. Computer Department, Xinzhou Teachers University, Xinzhou, Shanxi 034000, China
Abstract：These errors of video extensometer are analyzed from the aspects of mechanical assembly, external vibration, and image processing. In addition, the out-plane error is analyzed in details and the correction method is proposed. To evaluate the performance of the correction method, real experiments were performed. The results showed the errors can be reduced by the optimization algorithm, and the relative accuracy can be maintained at 0.5%, which achieved the extensometer classification of 0.5 level.
［1］Baida H A, Kermouche G, Langlade C. Development of an improved method for identifying material stress-strain curve using repeated micro-impact testing ［J］. Mech Mater, 2015, 86(2): 11-20.
［2］徐汉涛. 一种组合双悬臂夹式引伸计 ［J］. 计量技术, 1990, (7): 9-11.
［3］邹广平, 邹佳星, 唱忠良, 等. 基于LabVIEW力与变形信号数据自动采集与检测 ［J］. 计量技术, 2007, (2): 33-35.
［4］张阳, 臧顺来, 郭翔, 等. 基于数字散斑应变测量法的薄板各向异性力学性能研究 ［J］. 材料工程, 2012, (4): 6-11.
［5］李婧宇, 朱飞鹏, 雷冬. 三维DIC在铸铁拉伸试验中的应变测量精度研究 ［J］. 力学季刊, 2015, 36(3): 434-441.
［6］孙涛, 梁晋, 蔡勇, 等. 用数字散斑法测量铜/铝复层板拉伸变形 ［J］. 光学精密工程, 2012, 20(12): 2599-2606.
［7］张敬敏,王春华,周巍松,等,视频引伸计的误差源解析 ［J］. 物理测试, 2013, 31(3): 25-28.
［8］Bathurst R J, Shinoda M. Strain measurement of geogrids using a video-extensometer technique ［J］. Geotech Test J, 2004, 27(5): 456-463.
［9］黄桂平, 李广云, 王保丰,等. 单目视觉测量技术研究 ［J］. 计量学报, 2004, 25(4): 314-317.
［10］Wang J, Shi F , Zhang J,et al. A new calibration model of camera lens distortion ［J］. Pattern Recognition, 2008, 41(2): 607-615.
［11］Zhou F Q, Chai X H, YE T, et al. Two-diemensional vision measurement approach based on local sub-plane mapping ［J］. Chin Opt Lett, 2015, 13(12): 121501.
［12］赵斌, 周军. 基于改进棋盘的角点自动检测与排序 ［J］. 光学精密工程, 2015, 23 (1): 237-244.
［13］Bai P, Zhu F, He X. Optical extensometer and elimination of the effect of out-of-plane motions ［J］. Opt Lasers Eng, 2015, 65: 28-37.
［14］赵启成, 王振清, 杜永军,等. 油管螺纹应力应变场的有限元分析与检测 ［J］. 计量学报, 2005, 26(3): 253-258.
［15］戴相录, 谢惠民, 王怀喜. 二维数字图像相关测量中离面位移引起的误差分析 ［J］. 实验力学, 2013, 28(1): 10-19.
［16］Gao D K, Wang Y Q, Zhou C L, et al. The 2d calibration error analysis and compensation in the visual measurement ［C］//IEEE 4th International Conference on Intelligent Human-Machine Systems and Cybernetics(IHMSC), Nanchang, China, 2012, 238-241.
［17］国家质量监督检验检疫总局.JJG 762—2007 引伸计 ［S］.2007.
2017, Vol. 38 
