Trade Fair Highlight

Exhibition hall 6 – Booth 6301

All-around 3D shape measurement of transparent objects with thermal fringe projection

The applicability of optical surface measurement methods depends strongly on the reflective properties of the material to be measured. Bright, matt-reflecting surfaces are ideal for optical 3D sensors. Such cooperative properties are not always present on parts and assemblies in production. Uncooperative, i.e. transparent, reflective or jet-black surfaces can only be measured with lower accuracy or not at all using conventional optical measurement systems, or require the application of an additional matte coating prior to measurement.

With sequential thermal fringe projection, the Fraunhofer Institute for Applied Optics and Precision Engineering IOF Jena has developed a method that makes uncooperative surfaces directly measurable. While conventional optical sensors record the light diffusely reflected from the surface, the »Glass360Dgree« system uses the thermal radiation emitted by the surface itself.

The sensor of the »Glass360Dgree« consists of a stereo pair of two thermal imaging cameras and a special projection system. The projection system directs the light of a 40-watt CO2 laser (wavelength 10.6 µm) as a narrow line onto the surface. After just a few milliseconds of irradiation, the object at this line shows an increased temperature of a few Kelvin. The thermal imaging cameras see this as a clear radiance contrast.

The principle of »Glass360Dgree« allows to apply the advantages of fast, optical, non-contact measurement technology even at uncooperative material classes. Objects made of transparent glass or plastic become just as measurable as highly glossy or jet-black components.

Contact

Product group

Systems and apparatus for image processing

Contact

  • Fraunhofer IOF
    Bildgebung und Sensorik
  • Albert-Einstein-Straße 7
  • 07745 Jena
  • Germany