Patent ID: 7184584

Claim:
A method for qualitatively evaluating a material including; providing at least one identification characteristic on a material to be evaluated; providing an evaluation device; determining at least one background reference value representing properties of a material to be evaluated in at least a part of a surrounding area of a material to be evaluated extending around said at least one identification characteristic; providing at least one mask reference representing one of a geometric outline of said at least one identification characteristic and a relative arrangement of said at least one identification characteristic and a second identification characteristic; storing said at least one background reference value and said at least one mask reference in said evaluation device; inspecting a material to be evaluated and determining actual image data of the material to be evaluated; forming a difference image using said actual image value and said background reference value; comparing said difference image and said at least one mask reference in said evaluation device and determining an actual position of said identification characteristic of a material to be evaluated; and using said actual position of said identification characteristics and blanking out areas of a material to be evaluated corresponding to said determined location of said actual position of said identification characteristic in a subsequent qualitative evaluation of a material to be evaluated.