Metrology comprises a pointwise sampling method and apparatus to determine the surface shape of an object. When applied to a plano, spherical, or aspherical surface of an optical element, suitable sensors must be used to avoid damaging.
Unlike surface-covering interferometric metrology, tactile profile measuring does not need any null systems or compensators. Coordinates of sample points are referenced against an intrinsic coordinate system, which is supplied by the machine after a calibration process.
Online access to SPIE eBooks is limited to subscribing institutions.