Logo PTB

R&D project

Workpiece influence on high-precision coordinate measurements with optical distance sensors

Period of the project

Start: January 2009
End:   March 2015 

Description of the project

High-precision optical sensors are used more and more frequently in the coordinate metrology. However, the determination of the measurement uncertainty is problematic for optical measurements. An important reason for this is the influence of the workpiece characteristics on the measurement result. In particular, errors caused by the reflection and scattering characteristics of the workpiece surface and the workpiece geometry are important.
It is intended to determine the workpiece influence (surface characteristics, inclination and material) on the measurement results of triangulation-based sensors (e.g. point triangulation, fringe projection, confocal microscopy and focus variation) experimentally and theoretically. For this purpose, reference standards with different characteristics will be developed and characterized. At the same time, the distribution of the scattered light will be modeled, which depends on the sensor and the surface of the workpiece. Afterwards the individual models will be combined into one complete model, and the modeling will be verified by experimental studies using the developed reference standards. Finally, it will be examined to what extent the results are applicable to correct systematic influences and whether the correction can be transferred to similar surfaces.


Deutsche Forschungsgemeinschaft (DFG), priority program 1159 (StraMNano)


Dr.-Ing. Ulrich Neuschaefer-Rube and Wiebke Ehrig