The combination of digital image correlation (DIC) and scanning electron microscopy (SEM) enables to extract high resolution full field displacement data, based on the high spatial resolution of SEM and the sub-pixel accuracy of DIC. However, SEM images may exhibit a considerable amount of imaging artifacts, which may seriously compromise the accuracy of the displacements and strains measured from these images. The current study proposes a unified general framework to correct for the three dominant types of SEM artifacts, i.e. spatial distortion, drift distortion and scan line shifts. The artifact fields are measured alongside the mechanical deformations to minimize the artifact induced errors in the latter. To this purpose, Integrated DIC (IDIC) is extended with a series of hierarchical mapping functions that describe the interaction of the imaging process with the mechanics. A new IDIC formulation based on these mapping functions is derived and the potential of the framework is tested by a number of virtual experiments. The effect of noise in the images and different regularization options for the artifact fields are studied. The error in the mechanical displacement fields measured for noise levels up to 5% is within the usual DIC accuracy range for all the cases studied, while it is more than 4 pixels if artifacts are ignored. A validation on real SEM images at three different magnifications confirms that all three distortion fields are accurately captured. The results of all virtual and real experiments demonstrate the accuracy of the methodology proposed, as well as its robustness in terms of convergence.

中文翻译：

---

新型数字图像相关框架中扫描电子显微镜成像伪影的校正

基于 SEM 的高空间分辨率和 DIC 的亚像素精度，数字图像相关 (DIC) 和扫描电子显微镜 (SEM) 的结合能够提取高分辨率的全场位移数据。然而，SEM 图像可能会出现大量的成像伪影，这可能会严重影响从这些图像测量的位移和应变的准确性。目前的研究提出了一个统一的通用框架来校正三种主要类型的 SEM 伪影，即空间失真、漂移失真和扫描线偏移。伪影场与机械变形一起测量，以最大限度地减少后者中由伪影引起的误差。为此，集成 DIC (IDIC) 扩展了一系列分层映射函数，这些函数描述了成像过程与力学的相互作用。导出了基于这些映射函数的新 IDIC 公式，并通过大量虚拟实验测试了该框架的潜力。研究了图像中噪声的影响以及伪影场的不同正则化选项。对于高达 5% 的噪声水平测量的机械位移场中的误差在所有研究案例的通常 DIC 精度范围内，而如果忽略伪影，则误差超过 4 个像素。在三种不同放大倍数下对真实 SEM 图像的验证证实，所有三个畸变场都被准确捕获。所有虚拟和真实实验的结果都证明了所提出方法的准确性，