Automatic camera calibration method

• US 20030156189A1
• Filed: 01/16/2003
• Published: 08/21/2003
• Est. Priority Date: 01/16/2002
• Status: Active Grant

• Current Assignee: Advanced Telecommunications Research Institute International
• Original Assignee: Advanced Telecommunications Research Institute International
• Inventors: Utsumi, Akira, Yamazoe, Hirotake
• Granted Patent: US 7,212,228 B2
• Time in Patent Office: Days
• US Class Current: 348/77
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

In an automatic camera calibration method in a system comprising a plurality of cameras, the automatic camera calibration method is characterized in that for each of the cameras, the estimated values of the position and posture of the camera are updated on the basis of observation information shared with the surrounding cameras and the estimated values of the respective current positions and postures of the surrounding cameras. An example of the observation information is the two-dimensional coordinate value of an image to be observed on an image plane of the camera and the size of the image to be observed.

Claims

1. In an automatic camera calibration method in a system comprising a plurality of cameras, the automatic camera calibration method comprising the step of:

updating, for each of the cameras, the estimated values of the position and posture of the camera on the basis of observation information shared with the surrounding cameras and the estimated values of the respective current positions and postures of the surrounding cameras.

2. The automatic camera calibration method according to claim 1, wherein

the observation information is the two-dimensional coordinate value of an image to be observed on an image plane of the camera and the size of the image to be observed.

3. The automatic camera calibration method according to claim 1, wherein

processing for updating the estimated values of the position and posture of each of the cameras comprises

a first step of calculating information related to the relative posture and relative position between the camera and the other surrounding cameras on the basis of the observation information shared with the other surrounding cameras and the estimated values of the respective current positions and postures of the camera and the other cameras, and

a second step of updating the estimated values of the position and posture of the camera on the basis of the information related to the relative posture and relative position calculated in the first step.

4. The automatic camera calibration method according to claim 3, wherein

each of the cameras holds the estimated value of the posture of each of the surrounding cameras, information related to the estimation precision of the respective postures of the camera and each of the surrounding cameras, the estimated value of the position of each of the surrounding cameras, and the estimation precision of the respective positions of the camera and each of the surrounding cameras, and

said second step of updating the estimated values of the position and posture of each of the cameras comprising the steps of

updating the estimated value of the posture of the camera on the basis of the information related to the relative posture calculated in said first step, the estimated value of the posture of each of the surrounding cameras which is held by the camera, and the information related to the estimation precision of the respective postures of the camera and each of the surrounding cameras, and

updating the estimated value of the position of the camera on the basis of the information related to the relative position calculated in said first step, the estimated value of the position of each of the surrounding cameras which is held by the camera, and the information related to the estimation precision of the respective positions of the camera and each of the surrounding cameras.

5. The automatic camera calibration method according to claim 1, wherein

the processing for updating the estimated values of the position and posture of each of the cameras is performed every time new observation information is obtained in the camera.

6. The automatic camera calibration method according to claim 1, wherein

the posture in a world coordinate system of at least one camera and the positions in the world coordinate system of at least two cameras are given as bases in order to determine world coordinates.

7. The automatic camera calibration method according to claim 1, wherein

the observation information is the two-dimensional coordinate value of an image to be observed on the image plane shared between at least the two cameras.

8. The automatic camera calibration method according to claim 7, wherein

in the processing for updating the estimated values of the position and posture of each of the cameras, processing for updating the estimated values of the position and posture of the camera on the basis of the observation information shared with the other surrounding cameras and the estimated values of the respective current positions and postures of the other cameras is performed in a distributed manner for the cameras.