Calibration algorithms for stylus profilometer

Abstract

In manufacturing the aspheric surface such as contact lens and compact disc, a precise measurement is required by the stylus profilometer. The form talysurf profilometer developed by Rank Taylor Hobson Ltd. is the most popular instrument which achieves very high resolution using laser interferometer tranducer. Due to the arcuate movement of the stylus tip, the measurement data are distorted from the exact form of a surface. It is therefore necessary to compensate the data to get the true locus of the stylus tip as the tranducer moves in lateral direction. Several constants which are coefficients of polynomials used for the compensation are computed through the calibration process. This thesis describes the measurement process by the form talysurf and the calibration process. Finally we develop the calibration algorithm which is competitive with the form talysurf in computing the calibration constants.