Thalmann R, Dändliker R
Appl Opt. 1987 May 15;26(10):1964-71. doi: 10.1364/AO.26.001964.
Heterodyne holographic interferometry provides automated interference phase measurement with high resolution and allows the quantitative evaluation of 3-D displacement and strain on solid objects. The fundamentals of heterodyning in double-exposure holography are reviewed and its possibilities and limitations are discussed in detail. Experimental results of strain measurement on a curved object surface are reported. Three double-exposure hologram recordings with different illuminations are used to get the vector displacement. Based on locally calculated derivatives of the displacement field, a sensitivity for the strain components of 1 microm/m with a spatial resolution of a few millimeters has been achieved. The features of heterodyne holographic interferometry are compared with those of quasiheterodyne (phase stepping) fringe interpolation.
外差全息干涉测量法可实现高分辨率的自动干涉相位测量，并能对固体物体上的三维位移和应变进行定量评估。本文回顾了双曝光全息术中的外差原理，并详细讨论了其可能性和局限性。报道了在弯曲物体表面进行应变测量的实验结果。使用具有不同照明的三张双曝光全息图记录来获取矢量位移。基于局部计算的位移场导数，实现了应变分量灵敏度为1微米/米，空间分辨率为几毫米。将外差全息干涉测量法的特点与准外差（相移）条纹插值法的特点进行了比较。
