Patent ID: 6166393
Filing Date: 2000-12-26
Classification: C23G,G01N

Abstract:
Method for automatic inspection of moving surfaces using at least three different illumination/observation channels, said method comprising the steps of:a) illuminating said surface to be inspected under a bright field condition by a first beam of light from a first light source, and receiving light of the first beam of light reemitted from said surface by a light sensitive sensor device to obtain a first signal;b) illuminating said surface 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, said first, second and third beams of light having different characteristics, and receiving light of the second beam of light and light of the third beam of light, respectively, reemitted from said surface by said light sensitive sensor device to obtain a second signal and a third signal; andc) deriving from said first, second and third signals a physical property of said surface.