A visual inspection system for surface mounted components based on color features

The object of this study is to develop a reliable and fast visual inspection system for surface mounted components after they have been placed in wet solder paste on a printed circuit board (PCB). In order to reach this goal, firstly, the features of the components under three colors (red, greed, blue) structure light source are analyzed. Then, a two-stages inspection process is presented. In the first stage, the horizontal and vertical integral projections of the component electrode were obtained after segmentation in the red subimage, based on the projections, the location of component was gotten by the sliding location window algorithm, then, the defects such as missing component, wrong component, shift and rotation were detected. In the second stage, the three color features were extracted from the component body and the Bayes classifier was used to inspect another wrong component class. The proposed inspection system have been implemented and tested with various types of components collected from production line. The experiment results have verified the validity of this scheme in terms of recognition rate and speed.