Patent ID: 6927409

Claim:
A method to detect defects ( 11 a, 11 b, 11 c ) in the section shape of a product ( 10 ), characterized in that it provides: a step of constructing and memorizing a plurality of families of functions, each family being able to describe a correlated type of defect ( 11 a, 11 b, 11 c ), or combination of defects, which can be found in a product ( 10 ) observed in relation to the processing performed on said product ( 10 ); a step of dimensional measuring of the shadow cast by said product ( 10 ) when it is illuminated by at least a beam of light; a step of constructing a graphical representation relating to the development of said dimension of the shadow for at least a specific dimensional sector of said product ( 10 ); and a step of comparing said graphical representation and said functions memorized to identify the function which most resembles the representation obtained by the detection in order to classify the type, and to determine the entity, of the defect ( 11 a, 11 b, 11 c ) present in the section of said product ( 10 ), wherein said graphical representation is the polar diagram of the development of the nominal diameter (“d”) of said product ( 10 ) as the angle at the center varies.