Stroboscopic phase-stepping digital speckle-pattern interferometry

In this paper, computer image processing techniques for the extraction of numerical data of vibration amplitude are presented using stroboscopic phase-stepping speckle interferograms. An automated analysis system based on IBM-PC microcomputer and PCVISION-plus Frame Grabber is developed which is able to acquire quantitative displacement information with high speed and accuracy. Effect of time integration during light pulses and f-number of image lens are discussed. Experimental results with out-of-plane resonant vibration metal plate are also given.