Abstract: Side illumination is combined with scanning interferometry to provide a means for measuring with a single data-acquisition scan surfaces that contain sections suitable for interferometric processing as well as sections that are not suitable because of lack of fringes produced by the measurement. In the sections where no fringes are produced, the irradiance detected during the scan is processed using a depth-from-focus mapping method to yield a corresponding measurement. The result is a complete profilometric measurement of the sample surface with a single scan. In addition, by increasing sample irradiance through side illumination, the structural features of the sample become markedly more visible than when illuminated only by the object beam of the interferometer, which greatly facilitates finding focus and identifying regions of interest for the measurement.

Abstract: A coordinate measuring machine is calibrated by taking optical measurements of an optical flat that includes a grating placed on its surface. The arm of the CMM capable of multi-directional translation in relation to an object is fitted with a white-light interferometric objective and optical measurements are taken of the flat while translating the objective (or the flat) in the coordinate direction subject to calibration. The objective may serve also as the probe of the CMM.