Frequency domain characterization of the vibrations of a tuning fork by vision and digital image processing

摘要

We demonstrate an experimental setup and associated digital image processing software for measuring the vibrational amplitude of a tuning fork with subpixel accuracy. Stroboscopic illumination allows the use of a standard video camera to explore the resonant frequencies up to the kHz range. No preliminary surface patterning is required because the image processing is based on features present in the object's structure. Because the tuning fork is a high quality-factor resonator, it can be used for demonstrating the spectral power distribution of various excitation signals and the temperature dependence of the resonance frequency. The procedure can be generalized to the measurement of the in-plane lateral displacements of any structure.