Research On Image Algorithm Of PCB Hole Detection System Based On AOI

With the development of the electronic industry,the market of Printed Circuit Board(PCB)needs to be improved,the PCB board drilling quality requirements are getting higher and higher for the market.PCB defect detection technology is a main technologies to improve the productivity of PCB industry and the level of industrialization.Automatic optical inspection(AOI)technology has been widely used in the industry,PCB detection technology research based on AOI in China is more backward than other countries,affected the domestic PCB product quality and market competitiveness.PCB image processing algorithm is the core of the PCB hole detection system,the complexity and stability of the PCB hole detection system is greatly affected by them.This paper studies the techniques of PCB algorithm for image hole detection system based on AOI are,the main contents are as follows:(1)By comparing with the traditional PCB detection methods,this paper introduces the advantage of AOI for PCB detection technology and the mainstream performance indication based on AOI for PCB detection machine,and a detailed description of the modules in the PCB hole detection system.(2)In the image pre-processing stage,through the research on PCB imaging characteristics,using median filtering,thresholding and contour tracking algorithm to extract the features of the PCB hole for subsequent operation.(3)In the stage of image registration,in contrast with the special area search method,the auxiliary positioning hole method,proposed a hole registration method based on RANSAC,the method through in certain conditions were randomly selected in line with the conditions of searching the hole pairs of points,by pairing points of transformation matrix treat the measured PCB and the corresponding standard edition of registration data,this method is not a positioning hole,adaptive search and the speed is so fast,fully meet the speed requirements for high speed testing.(4)Through the research of defect type hole PCB,designed to meet the requirements of the detection system of PCB hole matching algorithm.Through the experiment,this method shows the accuracy,stability,high speed etc.