PCB Defect Inspection And Marking Based On X-ray Image

Aimed at the special requests for PCB defects test in X-ray image, the paper studies themain techniques in the inspection and marking process.In the industry defect detection,the defects, such as BGA joint short-circuit,missing theball and circuit breakage, occasionally appear in the PCB process,because it has manyproblems in the jointing process.The defect inspection and recognition is very important.Theinspection and recognition technology makes the X-ray real time inspection system objectiveand standard.According to detective theory of image system, the paper adopts a high resolution anddefinition X-ray real time inspection system on PCB defect.It can test and mark the defectsautomatically, at last distinguish the defect in PCB image. The following are the maincontents in the paper.1.There is much redundant background informations for defects detection in the image.Therefore we use an automatic method of PCB area based on the iterative thresholdsegmentation and mathematical morphology in this paper.This method detaches the defectsand background successfully and its results is satisfaction.2.The paper analyses PCB defects feature and fixs the method of the defectsextraction.The Hough can extract automatically PCB BGA joint missing the ball and thesubtraction method can extract automatically PCB BGA joint short-circuit and PCB circuitbreakage."Remove the peel"can get the regional center,so it can mark the accurate locationin the PCB defects image.3.According to pattern recognition theory and frame,the paper fixes the recognition methed in the PCB defects image. The"tree systematization"method and sequentialprobability ratio test can distinguish PCB BGA joint short-circuit and PCB circuit breakage.We can get the positions and classes of the defects clearly.