National Taiwan University of Science and Technology
Deep learning-based automatic optical inspection system empowered by online multivariate autocorrelated process control
Defect identification of tiny-scaled electronics components with high-speed throughput remains an issue in quality inspection technology. Convolutional neural networks (CNNs) deployed in automatic optical inspection (AOI) systems are powerful for detecting defects. However, they focus on individual samples but suffer from poor process control and lack of monitoring and providing the online status regarding the production process. Integrating CNN and statistical process control models will empower high-speed production lines to achieve proactive quality inspection. With the performance of the average run length for a certain range of the shifts, the proposed control chart has high detection performance for small mean shifts in quality. The proposed control chart is successfully applied to an electronic conductor manufacturing process. The proposed model facilitates a systematic quality inspection for tiny electronics components in a high-speed production line. The CNN-based AOI model empowered by the proposed control chart enables quality checking at the individual product level and process monitoring at the system level simultaneously. The contribution of the present study lies in the proposed process control framework integrating with the CNN-based AOI model in which a residual-based mixed multivariate cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control chart for monitoring online multivariate autocorrelated processes to efficiently detect defects.