METHOD FOR CALIBRATING A CAMERA AND CALIBRATION SYSTEM

• US 20180160110A1
• Filed: 12/01/2017
• Published: 06/07/2018
• Est. Priority Date: 12/05/2016
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Koesters, Damian, Blott, Gregor
• Granted Patent: US 10,341,647 B2
• Time in Patent Office: Days
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30204 Marker
• CPC Class Codes: G06T 2207/30241 Trajectory
• CPC Class Codes: G06T 5/40 using histogram techniques
• CPC Class Codes: G06T 5/94 based on local image properties, e.g. for local contrast enhancement
• CPC Class Codes: G06T 7/30 Determination of transform parameters for the alignment of images, i.e. image registration
• CPC Class Codes: G06T 7/80 Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
• CPC Class Codes: H04N 1/3876 Recombination of partial images to recreate the original image
• CPC Class Codes: H04N 1/6027 Correction or control of colour gradation or colour contrast H04N1/6058 takes precedence
• CPC Class Codes: H04N 17/002 for television cameras
• CPC Class Codes: H04N 23/698 for achieving an enlarged field of view, e.g. panoramic image capture
• CPC Class Codes: H04N 23/81 for suppressing or minimising disturbance in the image signal generation

Abstract

A method for calibrating a camera. The method includes a step of reading in and a step of ascertaining, an imaging trajectory and a reference trajectory of a moving calibration object detected by using the camera being read in in the step of reading in, the imaging trajectory representing a trajectory imaged in image coordinates of the camera and the reference trajectory representing the trajectory in world coordinates, and at least one calibration parameter for the camera being ascertained in the step of ascertaining by using the imaging trajectory and the reference trajectory.

Claims

1. A method for calibrating a camera, the method comprising:

reading in an imaging trajectory and a reference trajectory of a moving calibration object detected by using the camera, the imaging trajectory representing a trajectory of the calibration object imaged in image coordinates of the camera and the reference trajectory representing the trajectory in world coordinates; and

ascertaining at least one calibration parameter for the camera by using the imaging trajectory and the reference trajectory.

2. The method as recited in claim 1, wherein in the reading in step, the imaging trajectory and the reference trajectory are read in in a time-synchronized manner.

3. The method as recited in claim 1, further comprising:

detecting the reference trajectory, in which at least one acceleration characteristic of the calibration object is detected to obtain the reference trajectory.

4. The method as recited in claim 3, wherein in the detecting step, a position of the calibration object is detected at a plurality of detection times in order to obtain the reference trajectory, in the reading in step, an image coordinate value of an image of the calibration object is read in at each detection time in order to obtain the imaging trajectory.

5. The method as recited in claim 3, wherein the detecting step is performed by using a detection device developed separately from the camera and the imaging trajectory is determined by using image information of the camera.

6. The method as recited in claim 1, further comprising:

moving the calibration object along the trajectory.

7. A calibration device designed to calibrate a camera, the calibration device designed to:

read in an imaging trajectory and a reference trajectory of a moving calibration object detected by using the camera, the imaging trajectory representing a trajectory of the calibration object imaged in image coordinates of the camera and the reference trajectory representing the trajectory in world coordinates; and

ascertain at least one calibration parameter for the camera by using the imaging trajectory and the reference trajectory.

8. A calibration system for calibrating a camera, the calibration system comprising:

a detection device for detecting a reference trajectory of a moving calibration object; and

calibration device designed to calibrate the camera, the calibration device designed to;

read in an imaging trajectory and the reference trajectory of the moving calibration object detected by using the camera, the imaging trajectory representing a trajectory of the calibration object imaged in image coordinates of the camera and the reference trajectory representing the trajectory in world coordinates, and

ascertain at least one calibration parameter for the camera by using the imaging trajectory and the reference trajectory.

9. The calibration system as recited in claim 8, wherein the detection device is developed as the calibration object that is movable along a trajectory and is detectable by the camera.

10. A non-transitory machine-readable storage medium on which is stored a computer program for calibrating a camera, the computer program, when executed by a processing unit, causing the processing unit to perform:

reading in an imaging trajectory and a reference trajectory of a moving calibration object detected by using the camera, the imaging trajectory representing a trajectory of the calibration object imaged in image coordinates of the camera and the reference trajectory representing the trajectory in world coordinates; and

ascertaining at least one calibration parameter for the camera by using the imaging trajectory and the reference trajectory.