Predicting the effects of vibration in phase shifting interferometry

The objective of this study is to find an analytical means of calculating the measurement error in phase-shifting interferometry 1 (PSI) due to mechanical vibration. The mathematical approach is inspired by linear systems theory and Fourier methods recently developed by Freischlad and Koliopolous 2 and by Larkin and Oreb. 3 The sensitivity of the interferometer to vibration is reduced to a phase-error transfer function, which includes such factors as the data sampling characteristics of the PSI algorithm, the video camera frame rate and integration time.