Method and apparatus for determining camera pose

• US 20060013437A1
• Filed: 06/22/2005
• Published: 01/19/2006
• Est. Priority Date: 06/22/2004
• Status: Active Grant

• Current Assignee: SRI International, Inc.
• Original Assignee: Sarnoff Corporation (SRI International, Inc.)
• Inventors: Bergen, James, Nister, David
• Granted Patent: US 7,613,323 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 7/73 using feature-based methods

Abstract

A method and apparatus for determining camera pose characterized by six degrees of freedom (e.g., for use in computer vision systems) is disclosed. In one embodiment an image captured by the camera is received, and at least two constraints on the potential pose are enforced in accordance with known relations of the image to the camera, such that the potential pose is constrained to two remaining degrees of freedom. At least one potential pose is then determined in accordance with the remaining two degrees of freedom.

Claims

1. A method for determining a potential pose of an image capturing device, said potential pose having six degrees of freedom, the method comprising:

receiving an image captured by said image capturing device, said image including images of at least;

a first known world point, a second known world point and a third known world point; and

imposing constraints on said potential pose in accordance with known relations of said image to said image capturing device, said imposing comprising;

enforcing constraints given by a first ray, a second ray and a third ray, where said first ray, said second ray and said third ray each project from said image capturing device to, respectively, said first known world point, said second known world point and said third known world point; and

determining at least one potential pose in accordance with said constraints.

2. The method of claim 1, wherein said enforcing comprises:

first enforcing constraints given by said first ray and said second ray, such that said potential pose is constrained to two remaining degrees of freedom; and

further constraining said potential pose in accordance with said third point, said third ray and said remaining two degrees of freedom.

3. The method of claim 2, wherein said remaining two degrees of freedom comprise:

a first degree of freedom representing a transformation of said third known world point; and

a second degree of freedom representing at least one possible position of a third ray projecting from said image capturing device to said third known world point,

4. The method of claim 3, wherein said first degree of freedom constrains a position of said third known world point relative to said image capturing device within an area defined by a circle and said second degree of freedom constrains a position of said third ray relative to said image capturing device within an area defined by a ruled quartic surface, said circle and said ruled quartic surface having a plurality of intersection points.

5. The method of claim 4, wherein each of said plurality of intersection points identifies a potential pose of said image capturing device with respect to said first world point, said second world point and said third world point.

6. The method of claim 5, wherein each of said plurality of intersection points is determined by extracting the roots of an octic polynomial.

7. The method of claim 1, wherein said image capturing device conforms to a non-central projection image formation model.

8. The method of claim 7, wherein said image capturing device comprises at least one of:

a multi-camera rig, a catadioptric camera, a dioptric camera or a multi-lens camera.

9. The method of claim 7, wherein said image capturing device is a stereo camera head.

10. The method of claim 7, wherein said image capturing device comprises a plurality of cameras positioned at different locations, relative orientations of said plurality of cameras being known.

11. The method of claim 7, wherein said image capturing device comprises a camera mounted to a vehicle for capturing a plurality of images as said vehicle moves.

12. A computer-readable medium having stored thereon a plurality of instructions, the plurality of instructions including instructions which, when executed by a processor, cause the processor to perform the steps of a method for determining a potential pose of an image capturing device, said potential pose having six degrees of freedom, the method comprising:

receiving an image captured by said image capturing device, said image including images of at least;

a first known world point, a second known world point and a third known world point; and

enforcing constraints on said potential pose in accordance with known relations of said image to said image capturing device, said enforcing comprising;

enforcing constraints given by a first ray, a second ray and a third ray, where said first ray, said second ray and said third ray each project from said image capturing device to, respectively, said first known world point, said second known world point and said third known world point; and

determining at least one potential pose in accordance with said constraints.

13. The computer readable medium of claim 12, wherein said enforcing comprises:

first enforcing constraints given by said first ray and said second ray, such that said potential pose is constrained to two remaining degrees of freedom; and

further constraining said potential pose in accordance with said third point, said third ray and said remaining two degrees of freedom.

14. The computer-readable medium of claim 13, wherein said remaining two degrees of freedom comprise:

a first degree of freedom representing a transformation of said third known world point; and

a second degree of freedom representing at least one possible position of a third ray projecting from said image capturing device to said third known world point,

15. The computer-readable medium of claim 14, wherein said first degree of freedom constrains a position of said third known world point relative to said image capturing device within an area defined by a circle and said second degree of freedom constrains a position of said third ray relative to said image capturing device within an area defined by a ruled quartic surface, said circle and said ruled quartic surface having a plurality of intersection points.

16. The computer-readable medium of claim 15, wherein each of said plurality of intersection points identifies a potential pose of said image capturing device with respect to said first world point, said second world point and said third world point.

17. The computer-readable medium of claim 16, wherein each of said plurality of intersection points is determined by extracting the roots of an octic polynomial.

18. The computer-readable medium of claim 12, wherein said image capturing device conforms to a non-central projection image formation model.

19. The computer-readable medium of claim 18, wherein said image capturing device comprises at least one of:

a multi-camera rig, a catadioptric camera, a dioptric camera or a multi-lens camera.

20. The computer-readable medium of claim 19, wherein said image capturing device is a stereo camera head.

21. The computer-readable medium of claim 18, wherein said image capturing device comprises a plurality of cameras positioned at different locations, relative orientations of said plurality of cameras being known.

22. The computer-readable medium of claim 18, wherein said image capturing device comprises a camera mounted to a vehicle for capturing a plurality of images as said vehicle moves.

23. An apparatus for determining a potential pose of an image capturing device, said potential pose having six degrees of freedom, the apparatus comprising:

means for receiving an image captured by said image capturing device, said image including images of at least;

a first known world point, a second known world point and a third known world point; and

means for enforcing constraints on said potential pose in accordance with known relations of said image to said image capturing device, said means for enforcing comprising;

means for enforcing constraints given by a first ray, a second ray and a third ray, where said first ray, said second ray and said third ray each project from said image capturing device to, respectively, said first known world point, said second known world point and said third known world point; and

means for determining at least one potential pose in accordance with said constraints.