The Development Of Detection System For Grating Surface Defect Based On Machine Vision

With the rapid development of Measurement and Control Technology,photoelectric encoder has gained wide applications. The grating that is the corecomponent of photoelectric encoder has an influence on the resolution, measurementaccuracy, and usability if its surface contains defect image. Nowadays, manualdetection is used as the main way for grating surface defect image detection, whichhas the characteristics of low precision, low detection efficiency and low automation.For the above shortcomings, a hardware platform for the grating surface defectdetection system has been designed and processed, which can make the surfaceimage information of grating spread automatically. A software named gratingsurface defect detection also has been developed, which make it easy for the aidedinteractive detection of grating surface defect and the automatic segmentation ofdefect barcode.Firstly, the selection for CMOS camera, zoom lens, electric two-dimensionaltranslational platform, stepper motor and micro-adjustable bracket has beencompleted, according to the imaging requirements and deploy principle. The gratingsurface image deployable device has been designed and processed, which includesgrating box, special transmission light and grating fast fixture. In addition, somebrief overviews for the operation principle of deployable device have beenconducted.Secondly, this paper has presented the grating surface defect detection softwarebased on the machine vision and digital image processing technology, brieflyintroduced the function of semi-automatic interactive detection system, analyzed andlisted the defect segmentation principle and running effects of the defect imageprocessing system in detail, finally realized the automatic segmentation of defectbarcodes.Thirdly, According to the built hardware platform and control requirements, adual-control mode which is made up of the software control and keyboard control isdeveloped. This paper has proposed the overall scheme of control system,summarized respectively the control principle of the dual-control mode, introducedthe MPC08SP movement control card, control keyboard and data converter, analyzed the grating back origin movement, rapid alignment movement, page typeoperation movement and backlash compensation principle, compared the advantagesand disadvantages of dual-control mode.Finally, in order to test the feasibility and accuracy of hardware platform anddetection software, two experiments have respectively conducted. The lightcharacteristics, page type operation and statistical analysis have been validatedthrough the semi-automatic interactive detection experiment, and the end results alsohave been analyzed. The automatic segmentation for defect barcode form readingimage has been finished through the defect image processing experiment, and therunning results of respective algorithm also have been analyzed.