Effective procedure for determination of unknown vibration frequency and phase using time-averaged digital holography

In time-averaged digital holography (TADH), one records a hologram of a periodically oscillating object by using the exposure time typically much longer than the oscillating period. Problems arise when the total available exposure time is restricted or when the oscillation period is unknown. In this work we investigate effects of short exposure time to the quality of the recorded hologram and show that, to record high fidelity information in a shortest possible time, close estimates of the oscillating period and the phase are required. To that end we propose an advanced procedure based on short hologram exposures that allows obtaining such estimates. The procedure is efficient both in the number of recordings and their total exposure time.