Method and device for recording the motion of reference points on vibrating structures

摘要

A vibrating object (3) track recording unit uses an electronic camera to record a measurement mark (2) on the object with exposure time adjusted for one period. Alternatively the exposure is adjusted for a series of images recording different parts of the track with varying camera aperture and correction processing to determine the light dark boundary. An independent claim is included for the procedure used by the unit. The measurement mark may be a laser (1) beam reflected onto a matte screen (5) by a mirror (3), the end of a fiber optic light guide bundle or a colored mark.