不同的散斑场会显示出不同的灰度分布特征,并对数字图像相关方法的计算结果有着重要影响。使用计算机模拟生成一系列单向拉伸图像和双向拉伸图像,并在生成的图像中添加噪声,从而获得一系列含噪声单向拉伸图像和含噪声双向拉伸图像。使用数字图像相关方法对无噪声图像和含噪声图像分别进行相关计算,并分析研究图像应变量与相关计算结果正确率间的关系,研究结果表明发现当图像的应变量在一定范围内时,数字图像相关方法计算结果的正确率较高。同时发现,当图像的应变量较小时,噪声对相关计算结果的影响较大,随着图像应变量的增大,噪声对相关计算结果的影响逐渐减小,当图像的应变量到达一定程度时,噪声对相关计算的影响就不明显了。

Different speckle fields show different gray distributions, which have an important influence on the results of the digital image correlation calculation. The computer simulation is used to generate a set of uniaxial tensile image and two-way tensile image. And then the noises are added in the generated images to get a new set of images. The digital image correlation is used to calculate the images before and after deformation. The results of the study show that the digital image correlation method calculation results get higher accuracy within a certain range of the image variable. At the same time, when the variable of the image is less, the noise has great influnce on the related calculation results. With the increasirg of the image variable, the effect of the noise gragually decreases. When the image variable achieves to a certain extent, the effect of the noise is unconspicuous.