LED cosmetic flaw vision inspection system

The paper describes a vision inspection system that is developed to detect diffused LED defects, namelyscratches, bubbles, contamination, blister/blemish, fuzzy dome andoff centre defects in less than 200 ms using a 200 MHz Pentium PC, a Matrox Genesis frame grabber and a Pulnix high speed camera. Various image-processing techniques are utilised for the inspection task. A machine vision approach that comprises pre-processing, image segmentation, clean up and feature extraction operations is implemented to perform the automated cosmetic flaw inspection. Based on 200 LED samples, the system was found to be 100% accurate in detecting LED dome defects on LEDs of different colour and intensity. The system can also classify defects into different categories and was found to be 90% accurate.