The Application Of Image Processing In The Positioning System For The Test Point Of PCB

Nowadays,electronic products are of great importance in various fields.As PCB is the vital part of telectronic products,its quality greatly affects the quality of electronic products.With the development of high-precision and high-density PCB,traditional methods of fault detection cannot meet the fault-positioning requirements of PCB with complex structures.Therefore,the research on the positioning faults of PCB has practical significance and economic value.The technology of image processing is applied to the positioning system for the test point of PCB in this paper,to realize the automation and intelligentization of the system.First of all,we design the overall scheme of the positioning system for the test point of PCB.We propose the hardware selection basis and select the light source,industrial camera and optical lens,to construct the system hardware platform.Based on the theory of image processing,the image processing system is designed.Then,we study the preprocessing algorithms of PCB.Through comparing and experimenting with different algorithms,we finally choose the algorithms of weighted average,median filtering,histogram equalization,optimal threshold segmentation and canny operator edge detection.And,we analyze the algorithms of positioning mark point and test point.Based on the features of algorithms and the application scenario,the algorithm of hough transform and template matching are applied to positioning the mark point of standard PCB image and real-time PCB image respectively.We design the method of positioning test point and choose the algorithm of decoupling after evaluation.Finally,we develop the software of the positioning system for the test point of PCB.Using Matlab and VisionPro,the software interface is developed.The software structure and overall flow are given,and the function of positioning test point is realized based on the algorithms above.Experiments on the image processing system and the integrated system show that the system designed can meet the positioning requirements of PCB test point.