title: Time-average TV holography for vibration fringe analysis.
abstract: Time-average TV holography is widely used method for vibration measurement. The method generates speckle correlation time-averaged J0 fringes that can be used for full-field qualitative visualization of mode shapes at resonant frequencies of an object under harmonic excitation. In order to map the amplitudes of vibration, quantitative evaluation of the time-averaged fringe pattern is desired. A quantitative evaluation procedure based on the phase-shifting technique used in two beam interferometry has also been adopted for this application with some modification. The existing procedure requires a large number of frames to be recorded for implementation. We propose a procedure that will reduce the number of frames required for the analysis. The TV holographic system used and the experimental results obtained with it on an edge-clamped, sinusoidally excited square aluminium plate sample are discussed.
authors.affiliation: Applied Optics Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai-600036, India.
authors.forename: Upputuri Paul
authors.initials: UP
authors.lastname: Kumar
authors.forename: Yanam
authors.initials: Y
authors.lastname: Kalyani
authors.forename: Nandigana Krishna
authors.initials: NK
authors.lastname: Mohan
authors.forename: Mahendra Prasad
authors.initials: MP
authors.lastname: Kothiyal