Research On Measurement System Of Machine Vision Based On Line Array CCD

With the development of automobile industry boom, the requirements of thedetection accuracy, efficiency and production automation for the parts are increasinglyhigh. Thanks to the rapid development of optical, electronic, precision machinery andcomputer control technology, visual inspection has gradually developed into a modernintegrated science technology, and with its advantages of high precision, fast speed,non-contact, it has been widely applied into many engineering testing in the neighborhood.By selecting the spark plug as the research subject, a set of static visual detectionsystem based on area array camera of existing production line is further improved andperfected. The line array camera for dynamic acquisition of image is carried out tocomplete clearance measurement of spark plug.(1) According to the function and main design requirements of the detectionsystem, automatic detecting device system for workpiece is designed. The hardware partsof the detecting devic are divided into mechanical transmission and vision imagingstructure. For the mechanical transmission structure, with the design of the servo system tocontrol ball screw motion, the move and accurate positioning of workpiece are realized.For the vision imaging structure, after the image acquisition card receives the signal pulseof encoder, the high frequency scan and high resolution linear array camera scan themoving workpiece line by line to finish the continuous shooting. Build up the testingsystem successfully, and configure the parameters of hardware equipment, and implementthe image datas acquisition for detecting parts.(2) Use the design software ProE to establish3D model of the camera-sidecomponents. Depending on the different installation locations in space of camera, useANSYS Workbench sofeware to set material property and meshing of the profile fixedwith camera. The finite element simulation of flexural deformation is made under thegravity of releted spare parts. According to the flexural deformation value obtained from the finite element simulation and the error value got from the assembly tolerance ofdetection device system, use fine-tuning adjustment devices to offset error, so as to ensurethe CCD plane and the workbench plane to keep a certain parallel to make the line arraycamera capture image which is not distorted, therefore improve image quality and reducethe systematic measurement error.(3) Based on the acquired images, select reasonable image processing algorithms.First use the median filter for image denoising. Then select the maximum variance methodin order to obtain the optimal threshold of the image, according to the threshold value tomake image threshold segmentation, so as to obtain the two value image clearly. Finallywith the Roberts edge operator, fast detection of image edge is realized. Through analysisof test results of several images processing, image features are obtained extractly by thisalgorithm, and the accuracy of measurement is ensured.(4) Design and Research on the software design of the detection system, realize theautomatic detection function for workpiece. Use MATLAB to complete the design of theuser interface of image processing. With the analysis of the experimental results obtainedfrom the detection device, the requirement of the measurement precision is matained,and it proves this measurement system design is of great feasibility.Practice has proved that with the linear array CCD capturing image, the accuracy andefficiency of spark plug measuring system can be improved. And provide the real-timeefficient technical means for automatic detection of manufacturing enterprises, and hasimportant theoretical research value and broad market application prospect.