Stroboscopic Holographic Interferometry Application Of Digital Techniques To The Study Of Vibrating Objects

Stroboscopic holographic interferometry is a very powerful tool for the study of vibrating objects1-3). Typically, a hologram of the stationary object is recorded with continuous illumination and processed in situ. The vibrating object is then viewed through the hologram using pulsed illumination at the vibration frequency. Real-time fringes are seen correponding to the deformation of the surface relative to its rest position. However, quantitative information is available only along the fringe maxima and minima. If the fringes are far apart and unequally spaced, determination of the actual amplitude distribution over the surface of the object is quite laborious and subject to errors. Ambiguities can also arise if some parts of the surface are vibrating in antiphase.