Full-field strain measurement using a two-dimensional Savitzky-Golay digital differentiator in digital image correlation
Full-field strain measurement using a two-dimensional Savitzky-Golay digital differentiator in digital image correlation
复制标题
DOI：
10.1117/1.2714926
复制
发表时间：
2007-03-01
影响因子：
1.3
通讯作者：
Hua, Tao
中科院分区：
文献类型：
--
作者：
Pan, Bing;Xie, Huimin;Hua, Tao
许多已发表的关于数字图像相关（DIC）的研究工作都集中在提高位移估计的精度上。然而，使用DIC在离散位置计算的原始位移场不可避免地被噪声污染。如果直接对原始位移场进行微分来计算应变场，则噪声会被放大，甚至在更高的水平上，并且由此产生的应变场是不可信的。基于二维多项式的局部最小二乘拟合原理，推导了二维Savitzky-Golay（SG）数字微分器，并将其用于由DIC得到的原始位移场计算应变场。计算过程可以通过将SG数字微分器与估计的位移场卷积来容易地实现。均匀和非均匀变形图像被用来验证所提出的技术。计算的应变场清楚地表明，所提出的技术是简单和有效的。(C)2007年，由光学仪器工程师协会（Society of Photo-Optical Instrumentation Engineers）主办。
Many published research works regarding digital image correlation (DIC) have been focused on the improvements of the accuracy of displacement estimation. However, the original displacement fields calculated at discrete locations using DIC are unavoidably contaminated by noises. If the strain fields are directly computed by differentiating the original displacement fields, the noises will be amplified even at a higher level, and the resulting strain fields are untrustworthy. Based on the principle of local least-square fitting using two-dimensional (2D) polynomials, a 2D Savitzky-Golay (SG) digital differentiator is deduced and used to calculate strain fields from the original displacement fields obtained by DIC. The calculation process can be easily implemented by convolving the SG digital differentiator with the estimated displacement fields. Both homogeneous and inhomogeneous deformation images are employed to verify the proposed technique. The calculated strain fields clearly demonstrate that the proposed technique is simple and effective. (C) 2007 Society of Photo-Optical Instrumentation Engineers.