Automated Optical Inspection System for O-ring based on Photometric Stereo and Machine Vision

摘要

This research is aimed to develop an AOI (Automated Optical inspection) system for O-ring inspection. Frist, an AOI system was implemented for the detection of surface scratches, flow marks, non-fills and indentations on elastomer O-rings with high surface reflection coefficients. The proposed system employs a multiple light source structures to realize Photometric Stereo. This eases the identification of O-ring contour and Bézier control points. Overall, the detection recall rate is 100% and accuracy reaches 96.56%. This paper also develops an AOI system for O-ring dimension measurement. The system analyzes the contour of O-ring and reversely calculate Bézier curve control points. Then, those control points utilized with De Casteljau's algorithm to estimate O-ring dimension with high accuracy.