Applicative Framework for End-to-End AOI Implementation
• Porosity detection . Since radial light is not reflected by concavities , the defects are well visible and much darker than the general surface . In a grey-scale image , the darker the visual color the lower the correspondent pixel value . Thus , the algorithm computes the average of the pixel values inside the isolated circumference and compares it to a defined threshold to discriminate between good and bad parts ( Figure 3-5 ).
The threshold is set in advance by means of elemental statistical analysis : 250 images of good components have been collected and pixel average values computed for each image . The threshold is set by averaging once again all the results obtained and decreasing the result by a factor equal to three times the standard deviation of the original population .
In this study , after assessing a lack of information in literature regarding concrete implementations of end-to-end AOI systems , the authors described a framework easily able to be adapted to existing manufacturing processes and requiring limited investments . Its technical feasibility , as well as its scalability , were demonstrated through two different use cases , where the proposed solution was integrated into existing vacuum and oil pumps assembly lines in a noninvasive manner .
Adaptability and easy implementation were the main advantages achieved .
[ 1 ] M . -J . -J . Wang and C . -L . Huang , ‘‘ Evaluating the eye fatigue problem in wafer inspection ,’’ IEEE Trans . Semicond . Manuf .
[ 2 ] O . Hecht and G . Dishon , " Automatic optical inspection ( AOI )," 40th Conference Proceedings on Electronic Components and Technology , 1990 , pp . 659-661 vol . 1 , doi : 10.1109 / ECTC . 1990.122259 .
[ 3 ] A . A . R . M . A . Ebayyeh and A . Mousavi , " A Review and Analysis of Automatic Optical Inspection and Quality Monitoring Methods in Electronics Industry ," in IEEE Access , vol . 8 , pp . 183192-183271 , 2020 , doi : 10.1109 / ACCESS . 2020.3029127 .
[ 4 ] " Subject index ," in IEEE Transactions on Industrial Electronics , vol . 46 , no . 6 , pp . 5-18 , Dec . 1999 , doi : 10.1109 / TIE . 1999.808022 .
[ 5 ] W . C . K . Olalia , " Advance technique for automatic optical inspection process optimization ," 2016 e-Manufacturing and Design Collaboration Symposium ( eMDC ), 2016 , pp . 1-4 .
IIC Journal of Innovation 15