Quantitative evaluation of vibration information

A fringe evaluation system for a vibration measurement is presented, which is based on the phase-stepping technique in stroboscopic double-exposure holographic interferometry. Vibration amplitude and bias deformation distributions can be derived directly from the phase- stepped patterns. Phase errors caused by the time integration during light pulses are investigated, and the selection of optimum system parameters is discussed. Digital image processing techniques are used to improve the signal-to-noise ratio in fringe patterns and provide high quality phase maps. Experimental results with out-of-plane resonant vibration objects are presented.