A Vehicle Outer Contour Dimension Measuring System Based On Computer Vision Technology

In recent years,car ownership in China is increasing,people are enjoying the convenience of a motor vehicle at the same time,early damage accidents and road infrastructure and other issues also occur frequently.Comprehensive Performance Testing vehicles become an effective means of maintaining good vehicle production and road traffic order to ensure good road infrastructure and road traffic safety,vehicle outer contour dimension detection is important in vehicle comprehensive performance testing.The traditional measurement methods are mostly manual measurement with measurement error and low efficiency,however automated measurement method commonly used infrared light curtains and laser radar combined computer vision laser radar measurement method,Features of infrared light curtain combination of laser radar measurements are: sampling frequency curtains restricted existing products with and measured the infrared light curtain needs to be installed wide receivers on the ground with is not conducive to the maintenance and difficult to achieve high measurement accuracy comprehensive measurement error of this approach is <2.5%;laser radar combined with computer vision measurement method with the hardware cost of this measurement method has decreased,but as it is difficult to improve the measurement sampling rate and occupy a larger space with a comprehensive measurement error <2%.In this paper,we have developed a vehicle outer contour dimension measuring system based on advanced computer vision detection technology,optics,electronics,computers and other high-tech.after solving a series of core technologies,we have developed a fully automated,visualization,network the outside dimensions measuring system.According to the machine vision inspection principles,we have established the vehicle outer contour detection system model,we studied the sequence of image stitching algorithm,template matching algorithm and target labeling algorithm,detail designed camera driver circuit,laser screen drive circuit,FPGA data acquisition circuit to solve the length,width,height data synchronization between measurement modules,established vehicle information management database for outside dimensions measured information storage and stored outside the vehicle contour projection and measurement process monitoring chart in the form of pictures to achieve a scientific and efficient data management.In the system development process,we resolved image stitching,image fusion,the camera speed synchronous acquisition infrared laser point cloud image,target labeling algorithm,camera calibration,error analysis and compensation and other technical difficulties.Ultimately we combine machine vision and laser technology to develop a set of curtains simplistic,low-cost,high-performance vehicle has independent intellectual property rights outer outline dimensions intelligent online measurement system,without affecting the normal running of the vehicle condition,can complete vehicle precision measure length,width,height and other characteristic parameters,real fast measurement line vehicle outer contour dimensions measuring instrument has been certificated at the Sichuan Provincial quality and Technical Supervision meteorology,and is currently the only one outside the vehicle the most accurate measurement contour size measurement system,and applied to Anyang,Zhengzhou,Luoyang and other places inspection station with good running results.