A lane line fast detection algorithm is proposed for lane departure warning in car assisted driving.DROI in the current lane is introduced

and the front area of vehicle at the bottom of the camera field is removed according to the space coordinate system. DROI is adjusted in real time based on PPHT to effectively solve vehicle interference in other lanes. In view of the disturbance of shrubs

fences

road piles and road surface signs in special road circumstances

an optimization model for lane line detection is established based on dynamic planning

which is selected from the candidate line segment detected by PPHT. On this basis

the center line position of the lane is further accurately positioned

and a lane departure warning model is established to realize lane departure warning.Experimental results show that the proposed algorithm can effectively improve the accuracy and robustness of lane departure warning.