CALIBRATING APPARATUS FOR ON-BOARD CAMERA OF VEHICLE

• US 20100245576A1
• Filed: 03/19/2010
• Published: 09/30/2010
• Est. Priority Date: 03/31/2009
• Status: Active Grant

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: SAIKI, Mitsuyoshi, INUI, Yoji, NAKAMURA, Keiichi
• Granted Patent: US 8,866,904 B2
• Time in Patent Office: Days
• US Class Current: 348/148
• CPC Class Codes: G06T 7/80 Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration

Abstract

There is provided a calibrating apparatus for an on-board camera of a vehicle, which allows speedy, yet reliable decision of acceptance/rejection of calibration result, with a simple apparatus construction, without depending on or being influenced by the calibration environment. An image processing target region on which an image processing for detection of each calibration point in each one of calibration markers in a camera-captured image which is a projecting plane of a camera coordinate system is displayed as a region frame in the form of a graphic image, in superposition with the camera-captured image.

Claims

1. A calibrating apparatus for an on-board camera mounted to a vehicle, comprising:

an image acquiring section for acquiring a captured image captured by the camera including, within a field of view, calibration markers arranged at a plurality of differing positions;

an image processing target region setting section for setting an image processing target region on which an image processing is to be effected for detecting a calibration point in each one of the plurality of calibration markers in the captured image;

a calibration point detecting section for detecting the calibration point in each one of the plurality of calibration markers in the image processing target region included in the captured image;

an adjusting section for automatically adjusting a camera parameter of the on-board camera, based on the detected calibration point; and

a display controlling section for causing a displaying section to display the image processing target region as a region frame in the form of a graphic image, with the image processing target region being superposed on the captured image.

6. The calibrating apparatus for an on-board camera according to claim 1, wherein:

when an initial value of the camera parameter when the on-board camera is mounted under the designed posture and at the designed position is set in the calibrating apparatus for the on-board camera, if the value of the camera parameter at the time of completion of the automatic adjustment by the adjusting section is same as the initial value of the camera parameter, said display controlling section causes the displaying section to display the region frame in a different display form than the form when the calibration point is detected by the calibration point detecting section.

8. The calibrating apparatus for an on-board camera according to claim 1, wherein said display controlling section causes the region frame to be displayed in a different display form than the form when the calibration point is detected by the calibration point detecting section, if a difference between confirmed coordinate as the theoretical calibration point obtained by using the camera parameter at the time of completion of the automatic adjustment by the adjusting section and the actual coordinate is equal to or greater than a predetermined decision threshold value.

10. The calibrating apparatus for an on-board camera according to claim 1, wherein said display controlling section superposes the region frame with the captured image during execution of the automatic adjustment by the adjusting section.

12. The calibrating apparatus for an on-board camera according to claim 1, wherein the apparatus further comprises an instruction input receiving section for receiving an instruction input for stopping/suspending the automatic adjustment by the adjusting section.

13. The calibrating apparatus for an on-board camera according to claim 12, wherein said display controlling section superposes a touch button for providing the instruction input with the captured image during execution of the automatic adjustment by the adjusting section;

and

said instruction input receiving section receives the instruction input in response to an operation made on said touch button.

2. A calibrating apparatus for an on-board camera of a vehicle, comprising:

an image acquiring section for acquiring a captured image captured by the camera including, within a field of view, calibration markers arranged at a plurality of differing positions in a three-dimensional reference coordinate system;

a calibration point distribution region setting section for setting, as a calibration point distribution region where initial coordinates of the respective calibration points in the calibration markers are distributed in a projecting plane of a three-dimensional camera coordinate system when the on-board camera has rotated by a predetermined angle about three respective orthogonal axes of the three-dimensional camera coordinate system,

said initial coordinates being coordinates of the calibration points which are determined in the projecting plane of the camera coordinate system, based upon an initial value of a camera parameter defining said camera coordinate system relative to said reference coordinate system,

said initial value of said camera parameter being a parameter that causes said camera coordinate system and said reference coordinate system to satisfy an ideal relationship with each other when the on-board camera is mounted under a designed posture and at a designed position;

a calibration marker distribution region setting section for setting the region where the calibration markers are distributed on the projecting plane as a calibration marker distribution region, based on the calibration point distribution region;

a calibration point detecting section for detecting the calibration point in each one of the plurality of calibration markers in the calibration point distribution region in the captured image corresponding to the projecting plane;

an adjusting section for automatically adjusting said camera parameter of the on-board camera, based on the initial coordinates and actual coordinates comprising the coordinates of said calibration point detected on the captured image as being specified as actual coordinates on the captured image; and

a display controlling section for causing a displaying section to display the calibration marker distribution region as a region frame in the form of a graphic image, with the calibration marker distribution region being superposed on the captured image.

3. The calibrating apparatus for an on-board camera according to claim 2, wherein said calibration point detecting section detects each calibration point in each one of the calibration markers for the calibration marker distribution area corresponding to the projecting plane as the target area.

4. The calibrating apparatus for an on-board camera according to claim 2, wherein said adjusting section effects the adjustment of the camera parameter, with correction of rotation of the camera coordinate system defined relative to the reference coordinate system.

5. The calibrating apparatus for an on-board camera according to claim 3, wherein said adjusting section effects the adjustment of the camera parameter, with correction of rotation of the camera coordinate system defined relative to the reference coordinate system.

7. The calibrating apparatus for an on-board camera according to claim 2, wherein:

when an initial value of the camera parameter when the on-board camera is mounted under the designed posture and at the designed position is set in the calibrating apparatus for the on-board camera, if the value of the camera parameter at the time of completion of the automatic adjustment by the adjusting section is same as the initial value of the camera parameter, said display controlling section causes the displaying section to display the region frame in a different display form than the form when the calibration point is detected by the calibration point detecting section.

9. The calibrating apparatus for an on-board camera according to claim 2, wherein said display controlling section causes the region frame to be displayed in a different display form than the form when the calibration point is detected by the calibration point detecting section, if a difference between confirmed coordinate as the theoretical calibration point obtained by using the camera parameter at the time of completion of the automatic adjustment by the adjusting section and the actual coordinate is equal to or greater than a predetermined decision threshold value.

11. The calibrating apparatus for an on-board camera according to claim 2, wherein said display controlling section superposes the region frame with the captured image during execution of the automatic adjustment by the adjusting section.

14. The calibrating apparatus for an on-board camera according to claim 2, wherein the apparatus further comprises an instruction input receiving section for receiving an instruction input for stopping/suspending the automatic adjustment by the adjusting section.

15. The calibrating apparatus for an on-board camera according to claim 14, wherein said display controlling section superposes a touch button for providing the instruction input with the captured image during execution of the automatic adjustment by the adjusting section;

and

said instruction input receiving section receives the instruction input in response to an operation made on said touch button.