Road vertical contour detection

A driver assistance system mountable in a host vehicle, wherein the driver assistance system includes a camera operatively connectible to a processor, wherein the driver assistance system is operable while the host vehicle is moving to detect a vertical deviation in contour of a road, wherein a first image is captured at a first time, a second image is captured at a second time later than the first time and a third image is captured at a third time later than the second time,

• wherein image points of the road in the first image are matched to corresponding image points of the road in the second image to compute a first homography which transforms the first image of the road to the second image of the road,
• wherein image points of the road in the second image are matched to corresponding image points of the road in the third image to compute a second homography which transforms the second image of the road to the third image of the road;
• wherein a chained homography is computed by chaining the first homography with the second homography and
• and by using by using the chained homography as an initial guess, a third homography is computed which transforms the first image of the road to the third image of the road.

A computerized method for detecting a vertical deviation in contour of a road, the method performable by a driver assistance system mountable in a host vehicle while the host vehicle is moving, wherein the driver assistance system includes a camera operatively connectible to a processor, the method comprising:

• capturing from the camera a first image of the road at a first time and a second image of the road at a second time;
• by matching image points of the road in the first image and corresponding image points of the road in the second image, computing a homography which transforms the first image of the road to the second image of the road;
• use the homography to align and warp the first image toward the second image to produce thereby a warped first image;
• compute the optical flow between the second image to the warped first image;
• comparing the optical flow with a road surface optical flow based on a road surface model to produce thereby a residual optical flow different from the road surface model, thereby producing a residual optical flow different from the road surface optical flow.