Function: Mark the lane lines from the video and save it
Description: This program designed for labeling the lane from the video. Only if you press the 'n' the present quadrilateral data will be written into txt file.
Hot keys:
ESC - quit the program
n - next frame of the video
z - undo the last label point
c - clear all the label
l - no left lane on the road
r - no right lane on the road
x - no lane on the road