Users of full-field measurement methods like Digital Image Correlation (DIC) often aim to perform measurements with the best trade-off between spatial resolution, bias and measurement resolution. Whenever two full-field methods are compared, it is essential that these criteria are taken into consideration. Recently a metrological efficiency indicator for full-field measurements has been proposed and discussed. This indicator combines measurement resolution and spatial resolution. It has been shown to be invariant to the subset size in the case of Local DIC. The goal of this article is to discuss a method, which determines both the spatial and the measurement resolutions for a given bias for two different DIC methods, in order to obtain the metrological efficiency indicator for each of these methods. The benefit of this indicator is that it does not depend on setting parameters such as the subset size, which are chosen by the user. As such, it can be considered as intrinsic to each technique, thus enabling fair comparison. Local DIC and triangular finite element based Global DIC will be the subject of this investigation. With this setting, their respective subset and triangular element sizes will be related to the spatial resolution of both methods for a given acceptable bias. By using the metrological efficiency indicator, the performance of the two methods will be compared and discussed to a new level of detail. Generally speaking, the indicator shows that the metrological performance of both methods is similar, confirming their popularity. However, it will be shown that, depending on the choice of what an acceptable bias is, one of the method may be preferred to another. The results show that for the specific DIC versions used in the study, for cases for which a significant bias is acceptable, Local DIC outperforms Global DIC, while the opposite is true in the case for which the bias requirements are more stringent. Finally, the quadratic versions of both DIC versions are shown to significantly outperform their respective linear versions.

中文翻译：

---

迈向表征全场测量技术的计量性能的标准

数字图像相关 (DIC) 等全场测量方法的用户通常旨在在空间分辨率、偏差和测量分辨率之间进行最佳权衡。无论何时比较两种全场方法，都必须考虑这些标准。最近提出并讨论了用于全场测量的计量效率指标。该指标结合了测量分辨率和空间分辨率。在本地 DIC 的情况下，它已被证明对子集大小是不变的。本文的目的是讨论一种方法，该方法为两种不同的 DIC 方法确定给定偏差的空间分辨率和测量分辨率，以获得这些方法中的每一种的计量效率指标。该指标的好处是它不依赖于用户选择的子集大小等设置参数。因此，它可以被视为每种技术的固有特性，从而能够进行公平的比较。局部 DIC 和基于三角形有限元的 Global DIC 将成为本次调查的主题。使用此设置，对于给定的可接受偏差，它们各自的子集和三角形元素大小将与两种方法的空间分辨率相关。通过使用计量效率指标，这两种方法的性能将被比较和讨论到一个新的细节水平。总体而言，该指标表明两种方法的计量性能相似，证实了它们的受欢迎程度。然而，将表明，取决于可接受的偏差是什么的选择，其中一种方法可能优于另一种方法。结果表明，对于研究中使用的特定 DIC 版本，对于可以接受显着偏差的情况，本地 DIC 优于全局 DIC，而在偏差要求更严格的情况下，情况正好相反。最后，两个 DIC 版本的二次版本都显示出明显优于它们各自的线性版本。