Grating Surface Defect Recognition Detection Algorithm And Application Research System

In recent years,the encoder is widely used in various industries,which makes the market demand a large proportion of increase.As a result,this also promotes the technical level of encoder manufacturers constantly development.Encoder uses circular grating chip as the signal storage element.It has a certain number of advantages such as high measuring precision,good running state stability,wide use interval,small occupied space,light weight,low power and low cost,etc.Its quality directly affects the service performance.Because of the limitations of grating manufacturing,its surface tends to produce star,chrome point,burr,break and other defects.At present,the detection methods of grating surface defects are mainly manual testing,which has a lot of shortcomings such as high labor intensity,strong subjectivity,high cost,and difficult to meet the detection requirements in terms of accuracy,efficiency and automation,etc.Therefore,this topic develop a detection system of grating surface defect based on image processing technology.Firstly,the technical requirements of this paper are analyzed,and the key technology of grating surface defect detection is determined,where the Optimization of some hardware must be carried out,for example designing the grating universal fixture and optimizing the control parameters.Secondly,using the image processing technology,preprocess of grating surface image is conducted,and several image processing algorithms are proposed.Preprocessing algorithms for image denoising,enhancement,and restoration of blurred image caused by motion are researched.Traditional image edge algorithms such as edge redrawing,edge detection are analyzed,and then a special edge redrawing algorithm is used to extract the grating surface profile.Then,ROI intercepts for the preprocessed image are conducted,and theareas to be detected are obtained.Parameter measurements are implemented after extracting the geometric features of target defect area.Defect feature extraction is carried out and then various surface defects of grating are identified and the detected unqualified area will be marked by algorithm.Finally,the application of this system is studied,such as the design of interactive keyboard and automatic warning device,and the optimization of the software system.Then different specifications of the grating are selected to make a test by this system.The overall performance,detection results and detection efficiency are significantly improved.Experimental results show that the grating surface detection system developed in this paper is feasible and effective.The defect recognition rate is above 95%,that is,the detection error rate is below 5%.Aiming at the grating whose diameter is less than 33-38 mm,the detection efficiency is up to 29 seconds each.