Vibration amplitude analysis with a single frame using a structured light pattern of a four-core optical fibre

Vibration amplitude measurement with a single frame using a structured light pattern of a four-core optical fibre is demonstrated both theoretically and experimentally for the first time. The structured light pattern of the four-core optical fibre consists of vertical and horizontal interference fringes. Using a digital CCD camera and the Fourier Transform analysis, such a light pattern is employed to study amplitude information of a vibrating object. Since the structured light pattern contains its own reference inside as the object vibrates there is no need to bring the object to a halt for taking a second digital frame at rest to utilise it for referencing purposes.