Research On The Inspection System Of PCB's Components

With the development of science and technology, electronic components integrated in the printed circuit board (PCB) are more and more, once a bit quality problem is found, the entire product becomes the scrap, then to bring huge loss to the manufacturer, therefore needing PCB's real-time inspection, but the artificial detection because of easy to leak and inefficient reasons already cannot satisfy requirement of production, otherwise the PCB's on-line automatic inspection system can solve these problems.This paper studies the application of the digital image processing technology in the printed circuit board defects online automatic inspection system, and designs the software. The whole system structure mainly includes PCB image Pre-processing, image fixing, bare PCB plate detection and electronic components testing four parts.(1) The paper studies color space transform,image enhancement, denoising and edge detection of PCB image separately, then puts forward an improved Canny color edge technology, and the results show that these edge position is accurate, edge information extracted are rich.(2) The PCB inspection requires high precision, a methord of image fixing to locate the image is proposed.(3) In view of bare PCB plate existing such as short-circuit, breakers, sag and convex defects, using euler number and regional area detection method to identify, and the results show that the detection algorithm is reliable.(4) The paper analyses recognition algorithm on components defects, including the horizontal resistance and capacitance identified by testing the H component color figure in HSI space, the SMD resistor using vertical projective method for testing, and chip polarity round detected by Hough transform, as well as proves the reliability of detection algorithm through the experiments.