Patent ID: 6201602
Filing Date: 2001-03-13
Classification: G01B,G01N

Abstract:
Method for the detection of foreign materials in a measurement object, comprising:illuminating the measurement object in a measurement chamber, the measurement chamber surrounding the measurement object, or surrounding the measurement object except for one or more slots, there being at least one light source for illuminating the measurement object;detecting at least a representative sample of the light having one or more wavelengths inside the measurement chamber which is taken uniformly over the entire measurement chamber;generating an electrical signal in accordance with the light having one or more wavelengths detected in the detecting step;deriving from the electrical signal an absorption value of absorption by the measurement object of the light having one or more wavelengths in the measurement chamber by determining the amount of light having one or more wavelengths lost from the measurement chamber; anddetermining from said absorption value whether foreign material is present in the measurement object.