Method and device for stabilization of a surround view image

1. A method for image stabilization of an image sequence of one or more cameras of a vehicle, the method comprising:

recording images of surroundings of the vehicle from one or more cameras of the vehicle;

projecting image points of the recorded images to a unit sphere, wherein the projection comprises applying a lens distortion correction;

calculating, for each of the one or more cameras, at least one vanishing point from the projected image points on the unit sphere;

tracking a motion of the at least one vanishing point; and

using the motion of the at least one vanishing point to calculate a corrected projection to a ground plane;

applying a lens distortion correction to obtain a corrected image;

detecting at least two corresponding straight lines in the corrected image;

deriving a position of a vanishing point of the at least two straight lines on a unit sphere;

tracking a motion of the vanishing point on the unit sphere;

deriving a change in orientation of the one or more cameras from the tracked motion of the vanishing point; and

deriving a scaling of the recorded images using the derived change in orientation.

2. The method of claim 1 , further comprising:

deriving, for each of the one or more cameras, a position deviation of the position of an image plane from the motion of the vanishing point and filtering the position deviation over time.

3. The method of claim 1 , further comprising:

detecting edges in the recorded images and projecting image points of the detected edges onto the unit sphere.

4. The method of claim 1 , wherein the distortion correction comprises applying a lens distortion correction that is based on a polynomial fish-eye model.

5. The method of claim 1 , wherein the recalculation of the corrected projection to a ground plane comprises deriving a scaling of the recorded images using the filtered position.

6. The method of claim 1 , wherein the image scaling comprises:

deriving a true distance between a camera of the surround view system and a ground surface; and

computing a scaling factor for an image pixel based on the derived true distance between the camera and the ground surface.

7. The method of claim 1 , wherein the vanishing point of the detected straight lines is derived by projecting the detected lines on a unit sphere and determining the intersection of corresponding great circles.

8. The method of claim 1 , wherein the tracking of the vanishing point comprises a tracking with a prediction filter.

9. The method of claim 8 , wherein input values of the prediction filter further comprise an input from a motion sensor of the vehicle.

10. A computer program product stored on a non-transitory computer readable medium for executing a method for image stabilization of an image sequence of one or more cameras of a vehicle, the method comprising:

recording images of surroundings of the vehicle from one or more cameras of the vehicle;

projecting image points of the recorded images to a unit sphere, wherein the projection comprises applying a lens distortion correction;

calculating, for each of the one or more cameras, at least one vanishing point from the projected image points on the unit sphere;

tracking a motion of the at least one vanishing point; and

using the motion of the at least one vanishing point to calculate a corrected projection to a ground plane;

applying a lens distortion correction to obtain a corrected image;

detecting at least two corresponding straight lines in a corrected image;

deriving a position of a vanishing point of the at least two straight lines on a unit sphere;

tracking a motion of the vanishing point on the unit sphere;

deriving a change in orientation of the one or more cameras from the tracked motion of the vanishing point; and

deriving a scaling of the recorded images using the derived change in orientation.

11. An image correction system for a motor vehicle comprising a computation unit with an input connection for receiving consecutive camera images from one or more cameras, the computation unit comprising an input connection for receiving images of surroundings of a vehicle from one or more cameras of the vehicle and a processing unit that is operative to:

project image points of the recorded images to a unit sphere, wherein the projection comprises applying a lens distortion correction;

calculate, for each of the one or more cameras, vanishing points from the projected image points on the unit sphere;

track a motion of the vanishing points;

calculate, for each of the one or more cameras, an error in a position of an image plane and filtering the position over time;

utilize the filtered position to calculate a corrected projection to a ground plane;

apply a lens distortion correction to obtain a corrected image;

detect at least two corresponding straight lines in the corrected image;

derive a position of a vanishing point of the at least two corresponding straight lines on a unit sphere;

track a motion of the vanishing point on the unit sphere;

derive a change in orientation of the one or more cameras from the tracked motion of the vanishing point; and

derive a scaling of the recorded images using the derived change in orientation.

12. A motor vehicle with an image correction system of claim 11 , wherein one or more cameras of the motor vehicle are connected to the computation unit of the image correction system.