Systematic errors in two-dimensional digital image correlation due to lens distortion
Systematic errors in two-dimensional digital image correlation due to lens distortion
复制标题
由于镜头畸变导致的二维数字图像相关的系统误差
DOI：
10.1016/j.optlaseng.2012.08.012
复制
发表时间：
2013-02-01
影响因子：
4.6
通讯作者：
Tang, Liqun
中科院分区：
文献类型：
--
作者：
Pan, Bing;Yu, Liping;Tang, Liqun
透镜畸变实际上存在于真实的光学成像系统中，引起记录图像中的非均匀几何畸变，并在二维数字图像相关（2D-DIC）测量的位移和应变结果中引起附加误差。在这项工作中，由于透镜失真的位移和应变的测量结果的系统误差的2D-DIC的理论研究使用径向透镜失真模型和实验通过易于实现的刚体，在平面内平移测试。理论分析表明，被测像点的位移和应变误差不仅与所用摄像机透镜的畸变系数成线性关系，而且还取决于它与畸变中心的距离和位移的大小。为了消除透镜畸变引起的系统误差，提出了一种简单的线性最小二乘算法，由刚体面内平移试验的畸变位移结果估计畸变系数，进而对畸变位移场进行校正，得到无偏的位移场和应变场。实验结果验证了理论推导的正确性和所提出的透镜畸变校正方法的有效性。(c)2012爱思唯尔有限公司保留所有权利。
Lens distortion practically presents in a real optical imaging system causing non-uniform geometric distortion in the recorded images, and gives rise to additional errors in the displacement and strain results measured by two-dimensional digital image correlation (2D-DIC). In this work, the systematic errors in the displacement and strain results measured by 2D-DIC due to lens distortion are investigated theoretically using the radial lens distortion model and experimentally through easy-to-implement rigid body, in-plane translation tests. Theoretical analysis shows that the displacement and strain errors at an interrogated image point are not only in linear proportion to the distortion coefficient of the camera lens used, but also depend on its distance relative to distortion center and its magnitude of displacement. To eliminate the systematic errors caused by lens distortion, a simple linear least-squares algorithm is proposed to estimate the distortion coefficient from the distorted displacement results of rigid body, in-plane translation tests, which can be used to correct the distorted displacement fields to obtain unbiased displacement and strain fields. Experimental results verify the correctness of the theoretical derivation and the effectiveness of the proposed lens distortion correction method. (c) 2012 Elsevier Ltd. All rights reserved.