METHOD FOR DETERMINING THE POSE OF A CAMERA AND FOR RECOGNIZING AN OBJECT OF A REAL ENVIRONMENT

• US 20120237085A1
• Filed: 09/16/2010
• Published: 09/20/2012
• Est. Priority Date: 10/19/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Metaio GmbH (Apple Inc.)
• Inventors: Meier, Peter
• Granted Patent: US 8,837,779 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 2207/30232 Surveillance
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments
• CPC Class Codes: G06T 7/30 Determination of transform parameters for the alignment of images, i.e. image registration
• CPC Class Codes: G06T 7/33 using feature-based methods
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06T 7/73 using feature-based methods
• CPC Class Codes: G06T 7/75 involving models
• CPC Class Codes: G06V 10/245 by locating a pattern; Special marks for positioning
• CPC Class Codes: G06V 10/768 using context analysis, e.g. recognition aided by known co-occurring patterns
• CPC Class Codes: G06V 20/20 in augmented reality scenes
• CPC Class Codes: G06V 20/64 Three-dimensional objects

Abstract

A method for determining the pose of a camera (22, 32) relative to a real environment (40) comprises the following steps: taking at least one image (50) of a real environment by means of a camera (22, 32), the image containing at least part of a real object (41), performing a tracking method that evaluates information with respect to correspondences between features associated with the real object (41) and corresponding features of the real object (41) as it is contained in the image (50) of the real environment, so as to obtain conclusions about the pose of the camera (22, 32), determining at least one parameter of an environmental situation, and performing the tracking method in accordance with the at least one parameter. Analogously, the method can also be utilized in a method for recognizing an object of a real environment in an image taken by a camera.

Claims

1. A method for determining the pose of a camera relative to a real environment, said method comprising the following steps:

taking at least one image of a real environment by means of a camera, the image containing at least part of a real object;

determining at least one parameter of an environmental situation;

performing a tracking method that evaluates information with respect to correspondences between features associated with the real object and corresponding features of the real object as it is contained in the image of the real environment, so as to obtain conclusions about the pose of the camera;

performing the tracking method in accordance with the at least one parameter.

2. The method of claim 1,

wherein the tracking method makes use of at least one optical tracking method that is initialized in accordance with the at least one parameter.

3. The method of claim 1,

wherein by means of the tracking method the pose of the camera is determined with one, two, three, four, five or six degrees of freedom.

4. The method of claim 1,

wherein the tracking method employs several tracking sensors that are different with respect to the sensor type.

5. The method of claim 4,

wherein the tracking method includes weighting of at least one of the tracking sensors in accordance with the at least one parameter.

6. The method of claim 1,

wherein the tracking method includes prioritization of method partial steps in accordance with the at least one parameter.

7. The method of claim 1, wherein a data model is employed that is compared with data of the image taken by the camera, the data model being selected in consideration of the at least one parameter of the environmental situation.

8. The method of claim 1,

wherein calculation of an uncertainty is effected in determining the camera pose by determination of a distance measure of the at least one parameter of the environmental situation and known ideal parameters of the tracking method with respect to a known environmental situation.

10. The method of claim 1,

wherein, for determining the at least one parameter of the environmental situation, at least one or more of the following items of information are used:

time of the day;

time of the year;

weather, in particular rain, clouds, sun and fog;

position of the moon;

snow conditions;

foliage of the trees;

altitude above sea level;

public events, in particular strong movements;

traffic situation;

position;

orientation in a world coordinate system;

histogram of the image;

temperature;

maintenance step.

11. The method of claim 1,

wherein the at least one parameter has an effect on minimum requirements with respect to successful retrieval of model data in the image, in particular determines a number of features associated with the real object, which are to be brought info conformity with corresponding features of the image of the real object in the image of the real environment.

12. The method of claim 1,

wherein a data model is used that is compared with data of the image of the real object in the image of the real environment;

and

wherein the at least one parameter has influence on the preparation and/or use of the data model.

13. The method of claim 12,

wherein a parameter vector per data model or per feature within the data model is stored.

14. The method of claim 12,

wherein the at least one parameter influences the kind of preparation of the data model, in particular influences the preparation of feature detectors and descriptors.

15. The method of claim 1,

wherein a data model is extracted from a number of individual models, said data model containing an intersection of information present in several environmental situations.

16. The method of claim 1,

wherein several partial systems respectively perform the method, wherein not each of the partial systems calculates a tracking situation itself, but finished situation information is made available to all partial systems, advantageously even a finished recognition or initialization model is made available to the partial systems.

17. The method of claim 16,

wherein the partial systems provide information on the environmental situation to a server provided or to a peer-to-peer process.

18. The method of claim 1,

wherein, by determining the camera pose, depth information with respect to at least one real object contained in the image is calculated, the depth information being used to blend in, in a display device, an occlusion model for occluding a real object, when virtual information superimposed on the real environment is occluded in the view by the real object to be occluded.

24. The method of claim 10,

which combines a SLAM method with the ascertaining of the environmental situation and stores a prepared data model together with information on the environmental situation.

9. A method for recognizing an object of a real environment in an image taken by a camera, said method comprising the following steps:

taking at least one image of a real environment by means of a camera, the image containing at least part of a real object;

performing an image recognition method providing information as to the recognition of the at least one real object in the image;

determining at least one parameter of an environmental situation; and

performing the image recognition method in accordance with the at least one parameter.

19. A method for providing a data model that is intended to be compared with data of an image taken by a camera in a method for determining the pose of a camera relative to a real object of a real environment or in a method for recognizing a real object of a real environment,

wherein

an environmental situation is ascertained or simulated and at least one parameter of the environmental situation is determined;

and

a data model is prepared that contains a basic description of the real object, various environmental situations are set or simulated and, for different environmental situations, a respective adapted data model is provided in accordance with the respective at least one parameter.

20. The method of claim 19,

wherein the basic description is a virtual 3D model of an environment.

21. The method of claim 20,

wherein the 3D model has textures applied thereto which before was freed from environmental situation-specific properties.

22. The method of claim 20,

wherein the 3D model is projected to the image plane with different light situations.

23. The method of claim 19,

wherein a data model is prepared that contains an intersection of information present in several different environmental situations.