Vibration measurement of micro-components by fringe projection method

Abstract

This paper presents an optical fringe projection method for measuring the dynamic micro-components. Using a programmable liquid crystal display (LCD) projector and a long working distance microscope (LDM), sinusoidal fringes are projected onto a micro-component. 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 which enables calibration of the optical setup for subsequent amplitude and frequency measurement of the vibrating components. To overcome the underexposure problem, a white light source (WLS) is incorporated and the dynamic range of the camera is increased by a factor of 6. Discrepancy in the measured vibration amplitude is less than 1%.