Metrological limitations of optical probing techniques for dimensional measurements.

Based on experimental results from a series of investigations, this paper deals with the metrological limitations of optical probing techniques in the field of dimensional metrology. The optical probing systems considered herein comprise an optical coordinate measuring machine, an experimental optical roundness tester and an optical measuring station for dimensions which is under development for integration in a production line. In all these cases, a single measurement micrometer accuracy is required but hard to achieve. The influences from sensor, optical system, illumination, object, background, and mechanical system, are evaluated. Guidelines are suggested which can be used to optimize the accuracy in measuring situations.