Development of Surface Flaw Inspection System using 3-channel Detection of Polarized Light Reflection

Abstract

According to the increase of requirements for the surface quality of steel sheet for car outer panels, a new automatic on-line inspection system for fine defects, called “pattern-flaw”, has been developed. The system can certainly detect harmful pattern-flaws by distinguishing them from harmless patterns, oil and processing liquid remainder, by adopting the principle of the 3-channel polarizing camera detection of polarized ligiht reflection from the steel sheet. It is confirmed that it achieves 100% of detection rate and less than 1% of over-detection rate as a result of the on-line comparative examination with the human inspection.