Rapid procedure for obtaining time-average interferograms of vibrating bodies

摘要

Abstract: A method for vibrational analysis by time-average holographic interferometry was developed, based on conventional holography, and especially suitable for laboratories not equipped with ESPI system. It overcomes the main drawback of conventional time-average recording: the inhibitively cumbersome procedure which requires recording a new hologram for each set of vibrational parameters. Only one holographic recording of the tested object at rest is needed, and image processing techniques are used to construct time-average holographic pictures of the vibrating body over any desired frequency (and amplitude) range. The method is simple, almost as rapid as ESPI (approaching real time), yielding pictures of good quality and fine details with resolution limited by that of the TV camera used. The method was applied to, and is demonstrated in the determination of vibrational modes of jet-engine blades. !