Driving fatigue is one of the main causes that result in highway crashes.The information from lane departure detection can evaluate the state of driving fatigue.This paper presents an algorithm combining scan line and region-growing method based on video images analysis

in which lane-marking recognition and driving deviation detection are realized.We use the region of interest(ROI) to figure out the current track of the driving vehicle

and give a frame disposal strategy concerning the track's parameter so as to meet the need for real time management.The result of our algorithm will provide necessary data for the future analysis of driving fatigue.