The temporal phase shifting method (TPS) is the most powerful technique in phase-shifting shearography. Numerous different phase-shifting algorithms have been developed to determine phase distribution for different applications. Most of them are applied with known phase shifts. In these cases, the accuracy of quantitative measurement using phase-shifting technique depends strongly on the accuracy of the phase shifter e.g. a piezoelectric transducer (PZT) which is responsible for generating the known phase shifts. Thus, phase shifter has to be calibrated. A new calibration method based on the so-called advanced iterative algorithm which provides stable convergence and accurate phase distribution with minimum three randomly shifted interferograms will be proposed in this paper. A fully automatic calibration procedure for calibrating of desired phase shifts and for evaluating the characteristic curve of phase shift over voltage change will also be presented.
展开▼
