1. wbk Institute of Production Science , 150232 Karlsruhe Institute of Technology , Karlsruhe , Germany
2. Institute for Measurement and Sensor Technology , TU Kaiserslautern , Kaiserslautern , Germany
3. Institute of Machining Technology , 14311 TU Dortmund University , Dortmund , Germany
4. 28464 Fraunhofer Institute for Nondestructive Testing IZFP , Saarbrücken , Germany