This paper analyzes the process of lane departure detection approach.In our vision-based Lane Departure Detection system

we use a single camera as input.In this paper

we discuss how to detect the lanes marking on the road and get the relationship between vehicle and road.Some measurements are derived to calculate TLC(time to lane crossing)

for measuring the position of the vehicle relative to the lanes.Besides

the forward-looking predicting mode is introduced to establish the relationship among driver

vehicle

and road.Further more

the criterion can be got to tell whether the vehicle is going to depart the lane without conscious.Simulations show that our vision-based lane departure approach does provide an effective alarm when the state of driver goes wrong.Experiments are taken on vision navigation system for HONGQI prototype

using lane change rather than lane departure.Images obtained from forward looking camera are preprocessed to gain lane markers

and TLC curve is then gained from the alteration of the lane markers position.The results prove that the analysis and simulation above can be feasible.The hazard of lane departure can be forecasted through the alteration of vehicle-road relationship and TLC parameter.