To resolve the problem of vehicle distance measurement based on monocular vision on structural road

the formula of distance calculation based on vanishing point of lane lines is deduced from the basic theory of imaging by a pinhole model camera.The calculation is related only to the actual distance between the camera and the point of near field of view without calibrating all parameters of the camera.Then the error factors are analyzed and experiments for the measurement of distance between the camera and the horizontal markings on the road is performed under different camera installing height

pitching and orientation angles.Compared with the actual distance

the results indicate that the effect of the small changes of installing height and orientation angles on distance measurement can be ignored

while the change of pitching angle leads to a large error.At last

the experiment of vehicle distance measurement is also performed with a preceding vehicle on the road.The result demonstrates that the relative error is less than 3 % and a high precision is reached.