Research on surface defect inspection for small magnetic rings

Surface defect characters of the small magnetic ring is diversiform and the diameter of surface defect is usually about 0.1mm, thus the magnetic ring existing defects used in industrial production is great security risks. However, currently the disadvantages of artificial visual method are cost high, efficiency low and etc. Therefore, a new method is needed to detect small magnetic ring automatically. In this paper, the design of the automatic inspection system is illustrated, the modified BHPF filter is used for de-noising and eventually the defect is located and recognized.