Method Of Estimating Imaging Device Parameters

• US 20150287203A1
• Filed: 04/08/2015
• Published: 10/08/2015
• Est. Priority Date: 04/08/2014
• Status: Active Grant

• Current Assignee: I2o3d Holdings Limited
• Original Assignee: I2o3d Holdings Limited
• Inventors: Baumberg, Adam Michael
• Granted Patent: US 9,396,542 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06T 19/006 Mixed reality object pose determination, tracking or camera calibration for mixed reality G06T7/00
• CPC Class Codes: G06T 2207/10004 Still image; Photographic image
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30204 Marker
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 7/73 using feature-based methods
• CPC Class Codes: G06T 7/74 involving reference images or patches
• CPC Class Codes: H04N 23/60 Control of cameras or camera modules

Abstract

A method is provided for estimating parameters of an imaging device with respect to an image of a scene said method comprising the steps of locating a target coordinate system in a scene, using an imaging device to capture an image of the scene, and processing the image using the target coordination system as a reference to estimate the parameters of the imaging device with respect to the image, wherein the target coordinate system comprises at least one planer target and wherein the at least one planar target contains a set of identifiable features with known relative positions.

Claims

1. A method for estimating parameters of an imaging device with respect to an image of a scene said method comprising the steps of:

locating a target coordinate system, comprising at least two planer targets, wherein each of the at least two planar targets individually contains a set of identifiable features with known relative positions within each respective planar target, in a scene;

using an imaging device to capture an image of the scene; and

processing the image using the target coordination system as a reference to estimate the parameters of the imaging device with respect to the image comprising the steps of;

identifying the identifiable features of the at least two planer targets belonging to target planes;

determining the relationships between the at least two planar targets to calculate the positions of the identifiable features in a 3D space; and

estimating the imaging device parameters using the calculated position of each of the identifiable features in the 3D space and associated 2D co-ordinates of each of the identifiable features determined from the image.

2. The method as claimed in claim 1 further comprising augmenting the image of the scene by displaying a rendered 3D model over the image of the scene.

3. The method as claimed in claim 1 wherein each planer target comprises a pattern of known size and position.

4. The method as claimed in claim 3 wherein each planer target comprises a series of dots with known relative positions.

5. The method as claimed in claim 4 wherein each planer target comprises a series of dots in an array.

6. The method as claimed in claim 5 wherein each planer target comprises a series of dots in a 2×

3 array.

7. The method as claimed in claim 4 wherein at least one of the dots is a contrasting colour to the other dots.

8. The method as claimed in claim 6 wherein the pattern of dots is arranged such that the pattern is not identical after a 180°

rotation.

9. The method as claimed in claim 1 wherein the imaging device comprises a camera.

10. The method as claimed in claim 1 wherein the image is a photograph or video still.

11. The method as claimed in claim 1 wherein the parameters of the imaging device to be estimated comprise the position and orientation of the imaging device.

12. The method as claimed claim 1 in which a plurality of images are captured.

13. The method as claimed in claim 1 wherein the step of determining the relationships between the at least two planar targets to calculate the positions of the identifiable features in a 3D space includes determining the relationships between a plurality of pairs of planar targets to calculate the positions of the identifiable features in a 3D space and combining the results.

14. The method as claimed in claim 13 wherein the combined results are averaged.

15. The method as claimed in claim 11 wherein more reliable results are combined and less reliable results are omitted.

16. The method as claimed in claim 15 wherein the reliability of the results are based on the percentage of images in which each of the planar targets of a pair are visible.

17. The method as claimed in claim 1 wherein processing may be offline, real-time or a combination of the two.

18. The method as claimed in claim 1 wherein the estimated parameters of the imaging device in relation to the image are used in the reconstruction of 3D information.

19. The method as claimed in claim 18 wherein the reconstruction of 3D information utilises standard techniques including shape-from-silhouettes.

20. The method as claimed in claim 18 wherein the 3D information may comprise surface geometry, 3D point data or 3D mesh models.

21. The method as claimed in claim 1 wherein 3D graphical elements are superimposed onto the images using the estimated parameters of the imaging device.

22. The method as claimed in claim 1 for use in augmented reality applications.

28. The method as claimed in claim 13 wherein more reliable results are combined and less reliable results are omitted.

29. The method as claimed in claim 28 wherein the reliability of the results are based on the percentage of images in which each of the planar targets of a pair are visible.

30. The method as claimed in claim 19 wherein the 3D information may comprise surface geometry, 3D point data or 3D mesh models.

23. A method for estimating parameters of an imaging device with respect to an image of a scene said method comprising the steps of:

locating a target coordinate system, in a scene;

using an imaging device to capture an image of the scene; and

processing the image using the target coordination system as a reference to estimate the parameters of the imaging device with respect to the image,

wherein the target coordinate system comprises at least two planer targets, wherein each of the at least two planar targets individually comprises a series of dots with known relative positions.

24. The method as claimed in claim 23 wherein each planer target comprises a series of dots in an array.

25. The method as claimed in claim 24 wherein each planer target comprises a series of dots in a 2×

3 array.

26. The method as claimed in any of claims claim 23 wherein at least one of the dots is a contrasting colour to the other dots.

27. The method as claimed in claim 26 wherein the pattern of dots is arranged such that the pattern is not identical after a 180°

rotation.