Research On The Surface Defect Detection Method Of Mobile Phone Cover Plate Based On Machine Vision

As an important part of the mobile phone,the defects on the cover will seriously affect the use value of the mobile phone.In view of the large production of mobile phone cover plates and the fact that the traditional manual inspection cannot meet the market demand,it is also the development trend of the industry to use machine vision instead of traditional manual inspection.Therefore,this project discusses some common types of surface defects and the existing detection theory,designs the overall scheme of the mobile phone cover surface defect detection system,compares and analyzes the experimental results of different pretreatment methods,makes in-depth research and designs on the mobile phone cover surface defect detection algorithm,and completes the relevant verified experiment.The main contents of this project are as follows:(1)The whole scheme design of mobile phone cover surface defect detection system is realized,the software and hardware components of the defect detection system are given,completed the analysis and selection of related hardware equipment and software algorithm.(2)The current commonly used image preprocessing technologies are compared and analyzed.According to the characteristics and detection requirements of the surface defects of mobile phone cover plate,Gaussian filter,maximum inter class variance method and Canny edge detection are used to process the detected image.(3)Aiming at the defect of IR hole on the surface of mobile phone cover plate,a roundness determination method of IR hole based on least square circle method is proposed.The circular IR hole is selected for roundness defect detection,and the roundness error evaluation method is mainly analyzed.Finally,the least square circle method is used to evaluate the roundness of circular IR hole.The feasibility and the effectiveness of the algorithm is verified by simulation and actual experiments.(4)Aiming at the defect of ink point on the surface of mobile phone cover plate,a surface defect detection method based on image difference algorithm is proposed;aiming at the defect logo on the surface of mobile phone cover plate,an improved surface defect detection method based on template matching is proposed.The typical surface defects of mobile phone cover plates are divided into ink point defects and logo defects.The image difference method and template matching method are mainly analyzed.Combined with the characteristics of the above defects,the traditional template matching algorithm is improved and the automatic edge searching algorithm is introduced,and the feasibility and effectiveness of the above method are verified by simulation and experiment.The experimental results show that the proposed algorithm is efficient and can effectively detect the surface defects of mobile phone cover,which has a certain guiding and promoting significance for the production of mobile phone cover.