Sampling moiré method (SMM) is widely used for measuring high-accurate displacements and strains. However, it provides accurate measurement only when the displacement is smaller than half of grating pitch due to defects on phase difference calculation. To overcome the shortage of SMM, we improve the performance of SMM by adapting the integer-pixel digital image correlation (DIC). The improved SMM is capable of measuring much larger displacements than half of the grating pitch with high accuracy. Through computer simulation, we analysed the displacement measurement accuracy of the improved SMM under various grating pitches and sampling pitches with multiple noise levels. Then the proper range of sampling pitch was obtained. Two independent experiments with short- and long-range sight-distances, respectively, were conducted to validate the accuracy of the improved SMM successfully. In conclusion, with a mean measurement accuracy of up to 1/350 of a pitch, the improved SMM can be used for measuring high-accurate in-plane displacement whether the displacement is greater than a half of grating pitch or not.

采样莫尔法 (SMM) 广泛用于测量高精度位移和应变。但是，由于相位差计算的缺陷，只有当位移小于光栅间距的一半时，它才能提供准确的测量。为了克服 SMM 的不足，我们通过调整整数像素数字图像相关 (DIC) 来提高 SMM 的性能。改进后的 SMM 能够以高精度测量比光栅间距一半大得多的位移。通过计算机仿真，分析了改进型SMM在不同光栅间距和多噪声级采样间距下的位移测量精度。然后得到合适的采样间距范围。分别具有短程和长程视距的两​​个独立实验，成功地验证了改进的 SMM 的准确性。综上所述，改进后的SMM平均测量精度可达1/350节距，无论位移是否大于光栅节距的一半，都可用于高精度的面内位移测量。