Abstract: In view of that the longitudinal warning system delay phenomenon caused by the low accuracy of longitudinal ranging results in traditional computer vision,a visual revision and projection reversion technique based method was developed for measuring the longitudinal distance between the two vehicles running in the same direction and having a significant risk of collision.A convergence state longitudinal early warning model was built after analyzing the defects in the traditional emanative distance detection models by using the elk test method.The static experiment based on target source plate shown that the average absolute and relative errors of distance measurement by the method are less than 2.6 m and 3.5% respectively in the 30-100 m range of distance.

Key words: computer vision, dynamics simulation, elk test, break distance, data fitting