Measurement of vibration amplitude by an optical fiber-based Moiré interferometer

A projected-fringe fiber-based moire interferometer is proposed to measure the local amplitude vibration of a diffuse surface. The technique is based on an optical fiber interferometer which projects interference fringes on the object surface. The visibility of these carrier fringes is modulated by a function of local amplitude vibration. Full-field quantitative analysis is performed by analyzing the fringe pattern with a 2-D Fourier transform method. Theoretical details, and experimental results are presented.