Error-compensating phase-calculation algorithm in rapid-switching double-pulsed holographic interferometry.

An algorithm is presented for calculating the phase difference that is obtained with rapid-switching, double-pulsed holographic interferometry. Imperfect switching between reference beams in between two laser pulses causes a distortion in the phase-stepped interferograms that results in erroneous phase calculation when conventional phase-calculating algorithms are used. Instead of estimating the error that is involved, an extra step is added to a more conventional algorithm such as Carré's algorithm, so that this leakage effect is compensated for. Thus the desired phase difference is found. Also, a measure is found for excluding unreliable calculations, based on the light intensities and phase steps for each pixel and the leakage ratios.