抄録
The production number of printed circuit boards (PCBs) is increasing very rapidly. To automize the PCB production, a visual inspection system for assembled PCB has been developed.
The system inspects many kinds of defects on assembled PCBs, such as parts missing, improper parts on PCBs, polarity error of diodes and capacitors and improper insertion of leads, using image processing techniques. The multi-step similarity vector method has been developed to read various character patterns of IC names from many manufacturers. To inspect polarity marks on movable parts with long leads, the flexible window system has been installed. The slitted light is casted on leads backside of PCB to inspect parts missing and improper insertion of leads.
To execute these variety of image processing at high-speed, the inspection system is equipped with a micro-programmable digital signal processor for image processing, the DSP-i. The DSP-i enables the system to inspect the various inspection functions 25 times faster than general purpose 16 bits microcomputers.
