New method for measuring dynamic response of small components by fringe projection

Abstract

We describe the use of an optical fringe projection method to measure the dynamic response of small components. In this method, sinusoidal fringes are projected on a small component using a programmable liquid crystal display (LCD) projector and a long-working-distance microscope (LDM). The image of the fringe pattern is captured by another LDM and a high-speed camera and subsequently processed by the fast Fourier transform (FFT) technique. A simple procedure is described that enables calibration of the optical setup for subsequent amplitude and frequency measurement of small vibrating components. A method that enhances the detection range of the system is also included.