Online automatic measurement of deflection for automobile based on digital image

It is an essential requirement to keep vehicles running along straight line on road for automobiles and it is also a key guarantee for traffic safety. However, because of certain errors during manufacture and assembly for automobile, there are some vehicles with big deflection lean to certain direction while running on flat road. To avoid vehicles with big deflection exceeding the limit offset coming down from product lines and selling to customers, automobile companies must pay a great attention to measurement of deflection for vehicles. In this paper, the development of a digital image system for the automatic measurement of deflection for automobile is reported. Such system facilitates automatic, efficient, robust and high precision measuring of deflection for vehicles. The digital image approach is described fully, with emphasis upon dedicated CCD imaging system, the image processing algorithms and the photogrammetry processing algorithms. Finally, the results of experimental testing of deflection measuring system in practical automobile company are presented. From analysis of the system and results, we can see that such digital image processing technique is available for measuring the offset of vehicles and such digital image system have the advantages of high accuracy, automatization, high efficiency and robustness.