Design of optical field of vision imaging for defect detection of paper and transparent film
To achieve synchronous detection of defects in the paper and transparent film layers of packaging boxes,we studied the synchronous imaging of the paper and film defect.Firstly,we established models for a standard sphere integral light field,an ellipsoidal integral light field,and an arc integral light field.We then simulated three different light fields using COMSOL Multiphysics 5.6 and compared their ray angle uniform-ity and irradiation uniformity.The parameters of ellipsoidal area integral light field are optimized by ortho-gonal simulation.Secondly,the packaging box was imaged using the ellipsoidal integral light field,the bright and dark field forward lighting.Physical detection and machine vision were used to detect five common de-fects in the packaging box,including oil stains,pressure marks,openings,bubble wrinkles,and breakages,to verify the effectiveness of defect imaging.The results show that the images can clearly present defect charac-teristics in the paper base and transparent film layers under ellipsoidal integral light field.The physical detec-tion rates for oil stains,pressure marks,openings,bubble wrinkles,and breakages were 96.2%,92.5%,100%,95%,and 92%,respectively.Anomaly detection rates were 98.6%,97.5%,100%,100%,98.4%,respectively.Detection rates of defects were 97.6%,96%,100%,97%,and 96%,respectively.This study indicates that the consistent optical path angle and irradiation intensity result in a uniform ellipsoidal integral light field.Con-sequently,transparent film imaging of the packaging box shows clear defect characteristics that satisfy the standards for industrial detection application.
optical path simulationtransparent film imagingspherical integrated light fielddefect feature imagingvisual inspectionCOMSOL Multiphysics 5.6 ray simulation
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