Fig. 2.

Multiplexed off-axis holography: (a) schematic of the recording procedure by simultaneous illumination with three pairs of reference and object beams; (b) spectrum of the recorded multiplexed off-axis hologram consisting of three incoherently superimposed interference patterns; and (c) representative numerically reconstructed double-exposure multiplexed hologram that is used for 3-D displacement measurements. The object of interest is a 1-cm diameter latex membrane, acoustically excited by a tone of 1.5 kHz. Sound-induced concentric fringe patterns and four painted marks used to test registration algorithms are visible on each of the reconstructed images.