Research On Vehicle Weld Gap Detection Technology Based On Image Processing

The position of the automotive industry in the national economy is extremely important.In its manufacture,the weld gap detection accuracy of vehicle affects the safety performance of automobiles.At present,the measurement of the gap size of the weld seam of the vehicle is basically measured by the feeler tool.The measurement accuracy of the method is not high and there is human error.In recent years,measurement technology based on image processing is a non-destructive testing method,improving the accuracy and stability of the measurement results.Based on the analysis of production requirements of vehicle weld gap detection,this paper designs a vehicle weld gap detection system based on image processing and completes hardware selection.During the actual measurement process,the camera illumination angle will cause the acquired weld image to be distorted.In addition,the rough and non-parallel edges of the weld seam of the vehicle cause problems such as broken lines,overlapping lines,and abnormal straight lines in the detected weld line.In order to solve the problems of the above detection,this paper mainly studies the following two aspects:1)The image distortion is eliminated by detecting the standard round workpiece,and the absolute size of the image pixels is obtained.In the aspect of standard circle detection,the ellipse detection algorithm of standard circle is studied.The ellipse fitting of the detected contour is performed by least square method.According to the detected long axis of the ellipse,the ellipse of the geometric deformation is corrected into a circle by using the projection transformation matrix.The image pixel unit is calibrated according to the pixel diameter of the detection standard circle.2)Detection of the weld gap straight line.In the aspect of weld gap linear detection,the straight line detection algorithm of weld gap is studied.The Hough transform is used to extract the linear parameters,and the extracted parameters are straight-line fitted by the least squares method to improve the detection accuracy to the sub-pixel level.In this paper,the effective straight line extraction method of weld gap is used to extend the broken lines in the inspection,the overlapping lines are combined,and the slope abnormal lines are eliminated.The weld gap calculation method is studied to obtain the actual distance of the weld gap.This paper mainly studies the key technology of vehicle weld gap detection system and develops a weld gap detection software.Through multiple sets of measurement experiments,it is shown that the measurement accuracy of the detection system designed in this paper meets the requirements of weld gap detection index,and the system can achieve accurate and stable measurement of the weld gap of the vehicle.