A high speed AOI algorithm for chip component based on image difference

In this paper, based on the images acquired from a 3-CCD color camera and a 3-color hemispherical circular illumination, a high speed algorithm is given to inspect the chip component. A statistical appearance modeling technique (SAM) is used to get the template which has preponderance than a rigid one. Before inspection, we use a high speed method to adjust the position of the component. Based on the difference image between component image and its template image, we use region differences to diagnose the defect. Finally, some experiment results are presented to show the validity of the algorithm. The common defects of missing component, insufficient solder, excessive solder, and open solder etc. can be identified properly by using the proposed algorithm. And the time spent on each component is less than 5 ms.