IMAGE CAPTURE ENVIRONMENT CALIBRATION METHOD AND INFORMATION PROCESSING APPARATUS

• US 20080292131A1
• Filed: 08/08/2007
• Published: 11/27/2008
• Est. Priority Date: 08/10/2006
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Uchiyama, Shinji, Takemoto, Kazuki, Endo, Takaaki
• Granted Patent: US 7,974,462 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06T 2207/30208 Marker matrix
• 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 13/246 Calibration of cameras

Abstract

In a method of calibrating an image capture environment based on a captured image obtained by capturing an image of a physical space by an image capturing unit that captures the image of the physical space, an image of the physical space is captured using the image capturing unit, an index serving as a reference for calibration is detected from the captured image of the physical space, the position and orientation of the image capturing unit are calculated from the detected index, and image capturing unit unique information, geometric information associated with the physical space, or the relationship between the image capturing unit and the physical space is calibrated using the obtained data.

Claims

1. A method of calibrating an image capture environment based on a captured image obtained by capturing an image of a physical space by an image capturing unit that captures the image of the physical space, the method comprising:

an imaging step of capturing an image of the physical space using the image capturing unit;

a detecting step of detecting an index serving as a reference for calibration from the captured image of the physical space;

a calculating step of calculating a position and orientation of the image capturing unit from the index detected in the detecting step;

a presenting step of presenting a virtual three-dimensional object which designates the next target position and orientation of the image capturing unit required to acquire calibration information; and

a calibrating step of calibrating one of image capturing unit unique information, geometric information associated with the physical space, and a relationship between the image capturing unit and the physical space using the index detected in the detecting step.

2. The method according to claim 1, wherein in the calibrating step, intrinsic parameter information of the image capturing unit is calibrated.

3. The method according to claim 1, wherein in the calibrating step, a position and orientation of the index allocated on the physical space are calibrated.

4. The method according to claim 1, wherein the image capturing unit comprises a measuring unit which measures one of a position, an orientation, and a position and orientation of the image capturing unit on the physical space by another method which is not based on the captured image, and

in the calibrating step, the measuring unit is calibrated.

5. The method according to claim 1, wherein in the presenting step, the three-dimensional object is three-dimensionally displayed at the target position and orientation on the physical space to be superimposed on an image of the physical space to have a real scale.

6. The method according to claim 1, wherein in the presenting step, a three-dimensional image configured based on a viewpoint that allows to look down at the index on the physical space, an object indicating the target position and orientation, and an object indicating a current image capture position, is superposed on an image of the physical space.

7. The method according to claim 1, wherein in the presenting step, the index on the physical space, an object indicating the target position and orientation, and an object indicating a current image capture position are reduced while maintaining an allocation relationship thereof, and the reduced images of the index and the objects are three-dimensionally displayed at predetermined positions on the physical space.

8. The method according to claim 1, wherein in the presenting step, the target position and orientation are compared with a current position and orientation of the image capturing unit, the target position and orientation are presented in a first display form if a difference between the two sets of positions and orientations falls outside a predetermined range, and the target position and orientation are presented in a second display form if the difference falls within the predetermined range.

9. The method according to claim 8, wherein the first display form displays an object which imitates an outer shape of the image capturing unit.

10. The method according to claim 8, wherein the second display form displays a rectangular frame indicating an image range to be captured by the image capturing unit.

11. The method according to claim 10, wherein the second display form displays a virtual object indicating vertex positions of the rectangular frame inside the frame.

12. The method according to claim 10, wherein the second display form allocates and displays a plurality of circular objects along an axis of sighting to have the axis of sighting of the image capture position and orientation at the target position and orientation as a center.

13. The method according to claim 1, wherein in the presenting step, the target position and orientation are compared with a current position and orientation of the image capturing unit, and a message to prompt a user to capture an image is displayed when a difference between the two sets of the positions and orientations falls within a predetermined range.

14. The method according to claim 1, wherein in the presenting step, only one of sequentially calculated results is displayed when there are a plurality of target positions and orientations, and the current target position and orientation are updated to the next target position and orientation when an image at the displayed target position and orientation is obtained.

15. The method according to claim 1, wherein in the presenting step, symbols indicating an image capture order are displayed near a plurality of objects that represent the target positions and orientations.

17. A control program for making a computer execute an image capture environment calibration method according to claim 1.

18. A computer-readable medium storing a control program according to claim 17.

16. An information processing apparatus for calibrating an image capture environment based on a captured image obtained by capturing an image of a physical space by an image capturing unit that captures the image of the physical space, said apparatus comprising:

an imaging unit adapted to capture an image of the physical space;

a detecting unit adapted to detect a target object serving as an index from the image captured by said imaging unit;

a measuring unit adapted to measure a position and orientation of said imaging unit;

a designating unit adapted to present a target position and orientation of said image unit to a user using a virtual three-dimensional object; and

a calibrating unit adapted to execute calibration using the index detected by said detecting unit.