Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.

Spectra-physics Visiontech Oy

Ari Harkonen

Timo H Piironen

Detlef Paul

Martti Karppinen

Pertti Kontio

In a method an an apparatus for automatic inspection of moving surfaces using at least three different illumination/observation channels, the surface to be inspected under a bright field condition is illuminated by a first beam of light from a first light source. The light of the first beam of light reemitted from the surface is received by a light sensitive sensor device to obtain a first signal. Then, the surface is illuminated under a dark field condition by a second beam of light and by a third beam of light from a second and a third light source, respectively, the first, second and third beams of light having different characteristics. The light of the second beam of light and the light of the third beam of light, respectively, reemitted from the surface are received by the light sensitive sensor device to obtain a second signal and a third signal. Finally, a physical property of the surface is derived from the first, second and third signals.

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Oulu, Finland

Ari Harkonen