In order to automatically adjust the line sensor in such a way that it is perpendicular to the measurement surface at a fixed working distance, a white-light interferometer was included in the line-based form-measuring system. By means of a fast white-light scan, the optimum angle of the sensor (with respect to the surface of the specimen) is determined in advance, before scanning the specimen using the line-based sinusoidal phase shifting interferometer. This produces accurate measurement results and makes it possible to also measure non-rotational specimens.
In this paper, the setup of the line-based form-measuring system is introduced and the measurement strategy of the sensor adjustment using an additional white-light interferometer is presented. Furthermore, the traceability chain of the system and the main error influences are discussed. Examples of form measurement results are shown.