Figure 4.
Minimal errors were found for the optically measured displacement and strain. A) In-plane edge distortion; B) Out-of-plane focus shifting; C) Large displacement tests showed the mean and maximal errors are −0.02 and 0.61-µm, respectively; D) Small displacement tests showed the mean and maximal errors are −0.03 and 0.38-µm, respectively. The initial gauge separation was 3.0-mm for panels C & D. LVDT value of zero corresponds to the center of the camera FOV. Linear regression and 95% confidence intervals are shown.