| || Measurement of out of plane dynamic deformations by digital speckle pattern interferometry
Author : Rajesh Kumar;Chandra, Shakher
Source : Defence Science Journal ; Vol:53(1) ; 2003 ; pp 115-121
Subject : 620.1 Material Science and Technology
Keywords : Dynamic deformations;Large deformations;Histogram equalisation;Symlet wavelet;Daubechies wavelet;Phase filter;Wavelet filter;Minimum phase filter ;Digital speckle pattern interferometry;Signal to noise ratio
Abstract : In this paper, measurement of dynamic deformations in a rectangular plate fixed at one end, using digital speckle pattern interferometry (DSPI), has been presented. To improve the measurement accuracy, a new filtering scheme has been developed. This scheme is based on the combination of average/ median filtering and Symlet wavelet filtering which enhances the signal-to-noise ratio in the speckle interferogram obtained from the DSPI. Experimental results show that this filtering scheme is quite effective in improving signal-to-noise ratio of the speckle interferogram. The measurements by DSPI and accelerometer are in good agreement. The DSPI technique can be implemented for measuring the large deformations as well.