DYNAMIC CALIBRATION METHOD FOR SINGLE AND MULTIPLE VIDEO CAPTURE DEVICES

• US 20110285858A1
• Filed: 08/05/2011
• Published: 11/24/2011
• Est. Priority Date: 02/19/2008
• Status: Active Grant

• Current Assignee: National Chiao Tung University (Government of The Republic of China)
• Original Assignee: National Chiao Tung University (Government of The Republic of China)
• Inventors: CHEN, I-HSIEN, WANG, SHENG-JYH
• Granted Patent: US 8,270,706 B2
• Time in Patent Office: Days
• US Class Current: 348/187
• CPC Class Codes: G06T 7/80 Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration

Abstract

The present invention discloses a dynamic calibration method for a single and multiple video capture devices. The present invention can acquire the variations of the pan angle and tilt angle of a single video capture device according to the displacement of the feature points between successive images. For a plurality of video capture devices, the present invention includes the epipolar-plane constraint between a plurality of video capture devices to achieve the goal of dynamical calibration. The calibration method in the present invention does not require specific calibration patterns or complicated correspondence of feature points, and can be applied to surveillance systems with wide-range coverage.

Claims

1. A dynamic calibration method for video capture device, comprising:

providing at least one video capture device for capturing at least one initial image;

panning or tilting said video capture device for capturing at least one successive image with different angles;

extracting at least one initial feature point from said initial image, and extracting at least one feature point from said successive image, wherein said feature point is corresponding to said initial feature point; and

acquiring variations of a pan angle and a tilt angle of said video capture device according to the displacement between said initial feature point and said feature point.

2. The calibration method of claim 1, wherein when said initial feature point comes from a moving object, discard said initial feature point.

3. The calibration method of claim 1, wherein when said feature point comes from a moving object, discard said feature point.

4. The calibration method of claim 1, wherein the rotation radius of said video capture device is far smaller than the distance between said video capture device and the observed 3-D spatial point from which said initial feature point comes.

5. The calibration method of claim 1, wherein the variations of said pan angle and said tilt angle of said video capture device are minute.

6. The calibration method of claim 1, wherein the step of acquiring the variations of said pan angle and said tilt angle of said video capture device further comprises:

back-projecting said initial feature point onto a pseudo plane to form a corresponding pseudo point; and

searching a pose of said video capture device so as to back project said feature point to said pseudo point on said pseudo plane.

7. The calibration method of claim 1, wherein said video capture device is a video camera.