The study of vibration patterns using real-time hologram interferometry

Abstract

The authors have applied real-time and real-time/time-averaged hologram interferometry and time-averaged holography to the visualization of the complete vibrational patterns on a variety of large objects. A simple hologram plate holder has been developed, which with normal processing techniques using selected photographic plates, enables the zero fringe condition to be readily obtained and maintained. The use of retro-reflective painted models with point source illumination enables small, inexpensive lasers to illuminate large objects and still retain short exposures by using fast photographic plates at the focused point of reflected object light. The retro-reflective paint does not depolarize the reflected light and thus high contrast fringes can be seen through the viewing hologram.