Application of two-dimensional correlation filters to laser-speckle interferometry

摘要

The method described here, based on the laser speckle interferometry, applies a two-dimensional correlation filter to speckle image data for driven and resting phases, to visualize the mode shapes of piezoelectric devices. Laser speckle interference, a periodic resonator excitation, charge coupled device (CCD) image captures and correlation filtering are effectively combined in this method. Even with a small amount of data, this method gives very clear, high-contrast mode shape images. We also show that both in-plane and out-of-plane vibrational images can easily be separated by choosing the incident angle of a collimated laser beam.