Flat surfaces can be checked very well automatically by evaluating the reflection of a light source on the surface. Evaluable reflections, however, only occur if the alignment of both the lighting and the sensor relative to the surface is exactly the same. If the surfaces under consideration are not flat, this alignment does not fit everywhere and evaluation of the reflection requires considerably more effort.
The Fraunhofer IOSB's RRE principle (retro-reflection ellipsometry) is used to evaluate the reflection of a light source on the surface in retro-reflection. It is not necessary to align the components of the inspection system precisely with the surface under investigation. The real-time image acquisition and evaluation of an RRE inspection system allows the inspection of flat and curved surfaces in a continuous process.