Pcb Visual Inspection System

Nowadays, Printed Circuit Board (PCB) plays an important role in electronic devices. The quality of electronic productions somewhat depends on that of Printed Circuit Board. Due to the fatigue, subjectivity and speed requirement, manual inspection is ineffective to inspect every complex board. To realize defect inspection autom atically, some vision detection system for the PCB by Virtual Instrument and computer vision are studied in this article.This paper proposes a new method for automatic component detection by computer. Based on digital image processing, we have studied different features of the PCB defection . In order to identify the disfiguration, we colligate advantages of some other Image identify methods and develop a way belonged to this thesis which based on image recognition technology. Some image preprocesses algorithms such as Histogram equalization, Median Filter are used for enhancing the SNR (Signal Noise Ratio) of the PCB image. In the procedure of defect detection and identification, a series of digital image processing algorithms are adopted to detect the lost and polarity fault of components by the way of Template Matching Algorithm. This process achieve the fast alignment and reference comparison between the PCB image with the template image. In a case of solder inspection, Mathematical Morphology is used to extract features of solder joints and judge whether there is solder joint or not. At last,to detect the fault of short Circuit and open circuit, Edge detecting Algorithm is used.In this paper,the software development adopts the NI Company's Virtual Instrument Labview and vision took it IMAQ Vision. The software realizes the function of complete detecting, image collection, image pre-process, the fault inspection of bared PCB, component matching inspection and solder joint inspection. It has the merit of easily operation, friendly interface, high reliability and so on.