Comparing laser and polychromatic confocal optical displacement sensors for the 3D measurement of cylindrical artefacts containing microscopic grooved structures. [In special issue: Metrology and Properties of Engineering Surfaces]

摘要

A scanning system has been developed for measuring the surface of early cylinder mechanical soundrecordings to high precision, both for surface preservation and for post-processing of the data to recoverthe sound encoded in the grooves. Research has identified that high sensor axial resolution is requiredto resolve the smallest amplitude groove modulations contained on typical cylinder artefacts resultingin the selection of confocal laser and white light (polychromatic) confocal sensors as suitable sensingtechnologies. This paper presents data acquired by the two confocal sensor technologies, comparing themeasured surface profiles with data obtained using a stylus profilometer. We investigate limitations ofthe sensors, relating their characteristics to the ongoing development of the scanning system.