Research On The Method Of Measuring The Initial Angle And Height Of The Wheel

Automobile wheels are the main stress component in automobilism,which bear various external forces.Therefore,whether there is fatigue crack in automobile wheel will affect the stability and safety of driving safety.At present,X-ray detection has been widely used due to its advantages of high imaging accuracy,wide detection depth and high real-time performance.In accordance with the need of wheel before undergoing X-ray flaw detection measuring wheel location problem in advance,this paper designed a set of measuring system measuring initial angle and the height,and then selected a appropriate device camera,and then completed camera calibration and color camera and depth camera registration to eliminate camera distortion influence on the accuracy of measurement.Next,in order to meet the measurement requirements of Angle and height,this paper mainly carried out three stages of work :(a)Wheel image preprocessing and interested area positioning;(b)Establishment of hub template database;(c)Design of Angle and height measurement algorithms.In the stage of wheel image preprocessing and interested area positioning,this paper designed a set of algorithm based on bilateral filtering to locate the region of interest hough circle transformation.In view of the disadvantage of traditional hough circle transform in the scene of automobile wheel image with low positioning accuracy,a set of hough circle screening algorithm based on Canny edge detection was proposed,and proved its advantages of high accuracy by experiments.In the stage of wheel database establishment,the purpose is to provide template image for subsequent angle detection algorithm and tell subsequent flaw detection system the current wheel hub model.For these two purposes,this paper compared and experimented the SIFT algorithm and SURF algorithm,and finally used SURF algorithm to extract the wheel image feature points to the database.When the hub comes,feature points are selected as matching points by using the ratio of minimum Euclidean distance and sub-small Euclidean distance,which needs to be less than 0.8.In the stage of measurement,for the measurement of the initial angle,this paperfirst implemented the hough line transform to detect the spoke line algorithm,and calculated its slope to calculate the angle algorithm.For the problem of the algorithm is not universal,then proposed an angle measurement algorithm based on gray scale comparison.For the measurement of wheel height,this paper first realized a set of process based on infrared light screen height measurement,and then because of its low simplicity,then designed a set of process based on Kinect’s infrared depth measurement system,which has the advantages of high real-time performance and good simplicity.