Method of calibrating a vehicular camera

• US 9,296,337 B2
• Filed: 10/05/2015
• Issued: 03/29/2016
• Est. Priority Date: 01/13/2010
• Status: Active Grant

• Current Assignee: Magna Electronics Incorporated (Magna International Incorporated)
• Original Assignee: Magna Electronics Incorporated (Magna International Incorporated)
• Inventors: Vico, Marko, Zibman, Sharon, Stefanovic, Aleksandar
• Primary Examiner(s): HSIA, SHERRIE Y
• Application Number:
  US14/874,999
• Publication Number:
  US 20160023603A1
• Time in Patent Office: 176 Days
• Field of Search: 348/148, 348/187, 348/188, 340/932.2, 340/937, 340/995.28, 340/435, 702/85, 702/94, 702/104
• US Class Current: 1/1
• CPC Class Codes: B60R 1/00 Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
• CPC Class Codes: B60R 11/04 Mounting of cameras operative during drive; Arrangement of controls thereof relative to the vehicle
• CPC Class Codes: B60R 2300/304 using merged images, e.g. merging camera image with stored images
• CPC Class Codes: B60R 2300/402 Image calibration
• CPC Class Codes: B60R 2300/806 for aiding parking
• CPC Class Codes: G06T 11/60 Editing figures and text; Combining figures or text
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30252 Vehicle exterior; Vicinity of vehicle
• CPC Class Codes: G06T 2207/30264 Parking
• CPC Class Codes: G06T 7/80 Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration

Abstract

A method of calibrating a vehicular camera installed in a vehicle, with the camera having an imager and a camera microcontroller, includes searching for and/or determining a reference point in the images and adjusting the position of an overlay applied to displayed images depending on the reference point. The method may include comparing the determined reference point'"'"'s actual position to its expected position and determining an offset amount with which to shift the overlay on the images displayed at an in-vehicle display responsive to the determined offset amount, and adjusting the position of the overlay applied to the images displayed at the in-vehicle display responsive to the determined offset amount.

Claims

1. A method of calibrating a vehicular camera installed in a vehicle, wherein the camera has an imager and a camera microcontroller, said method comprising:

(a) determining whether the contrast in images received by the imager is beyond a selected threshold value;

(b) searching for a reference point in the images depending on the result of step (a) using the camera microcontroller; and

(c) adjusting the position of an overlay applied by the microcontroller to the images depending on the result of step (b).

2. The method as claimed in claim 1, wherein step (b) includes:

(d) selecting a search window within the images;

(e) dividing the search window into a plurality of bars, wherein each bar corresponds to a plurality of pixels on the imager;

(f) receiving data relating to brightness levels of the bars; and

(g) detecting the position of the reference point based on changes in brightness levels from bar to bar.

3. The method as claimed in claim 2, wherein the search window selected in step (d) is a vertical position search window and wherein step (b) further includes:

(h) selecting a rotation angle detection search window;

(i) searching for the positions of a plurality of rotation angle reference points; and

(j) determining whether to adjust the position of the overlay rotationally based on the results of step (i).

4. The method as claimed in claim 1, wherein step (b) includes:

(d) selecting a search window within the images;

(e) selecting a rotation angle detection search window;

(f) searching for the positions of a plurality of rotation angle reference points; and

(g) determining whether to adjust the position of the overlay rotationally based on the results of step (f).

5. The method as claimed in claim 1, wherein step (b) includes determining the reference point iteratively using data from the camera.

6. The method as claimed in claim 1, wherein step (b) includes determining the reference point and determining an offset amount with which to shift the overlay on the images.

7. The method as claimed in claim 6, wherein the reference point is at an edge of the bumper of the vehicle.

8. The method as claimed in claim 1, comprising determining a rotation angle of the camera and adjusting the position of the overlay based on the determined rotation angle.

9. The method as claimed in claim 8, comprising emitting near-infrared light via a near-infrared light source towards a location where the reference point may be determined.

10. The method as claimed in claim 9, wherein the reference point is at an edge of the bumper of the vehicle, and wherein near-infrared light is emitted towards the bumper of the vehicle.

11. The method as claimed in claim 1, comprising providing images captured by said camera to an in-vehicle display.

12. The method as claimed in claim 11, comprising applying the adjusted overlay to images displayed at the in-vehicle display.

13. A method of calibrating a vehicular camera installed in a vehicle, wherein the camera has an imager and a camera microcontroller, said method comprising:

(a) searching for a reference point in images captured by the camera using the camera microcontroller;

(b) providing the images to an in-vehicle display;

(c) applying an overlay to images displayed at the in-vehicle display;

(d) determining the reference point and determining an offset amount with which to shift the overlay on the images displayed at the in-vehicle display; and

(e) adjusting the position of the overlay applied to the images displayed at the in-vehicle display responsive to the result of steps (a) and (d).

14. The method as claimed in claim 13, wherein step (a) includes:

(f) selecting a search window within the images;

(g) selecting a rotation angle detection search window;

(h) searching for the positions of a plurality of rotation angle reference points; and

(i) determining whether to adjust the position of the overlay rotationally based on the results of step (h).

15. The method as claimed in claim 13, wherein step (a) includes determining the reference point iteratively using data from the camera.

16. The method as claimed in claim 13, comprising determining a rotation angle of the camera and adjusting the position of the overlay based on the determined rotation angle.

17. A method of calibrating a vehicular camera installed in a vehicle, wherein the camera has an imager and a camera microcontroller, said method comprising:

(a) determining a reference point in images captured by the camera using the camera microcontroller;

(b) comparing the determined reference point'"'"'s actual position to its expected position;

(c) providing the images to an in-vehicle display;

(d) applying an overlay to images displayed at the in-vehicle display;

(e) determining an offset amount with which to shift the overlay on the images displayed at the in-vehicle display responsive to step (b); and

(f) adjusting the position of an overlay applied to the images displayed at the in-vehicle display responsive to the result of step (e).

18. The method as claimed in claim 17, comprising determining a rotational offset in the images responsive to step (b) and adjusting the position of the overlay based on the determined rotational offset.

19. The method as claimed in claim 17, wherein step (a) includes determining the reference point iteratively using data from the camera.

20. The method as claimed in claim 17, wherein step (a) includes:

(f) selecting a search window within the images;

(g) selecting a rotation angle detection search window;

(h) searching for the positions of a plurality of rotation angle reference points; and

(i) determining whether to adjust the position of the overlay rotationally based on the results of step (h).