POSITION AND ORIENTATION ESTIMATION METHOD AND APPARATUS THEREFOR

• US 20120320053A1
• Filed: 01/12/2011
• Published: 12/20/2012
• Est. Priority Date: 02/25/2010
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Miyatani, Sonoko
• Granted Patent: US 9,153,030 B2
• Time in Patent Office: Days
• US Class Current: 345/420
• CPC Class Codes: G06T 2207/10004 Still image; Photographic image
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/75 involving models

Abstract

There is provided a method for accurately estimating a position and orientation of an object even if the object is more dispersive in shape than a three-dimensional geometric model with a standard shape. The statistic of deviation of a feature constituting a three-dimensional model representing a three-dimensional standard shape of an object is estimated to determine a reliability for each feature. The amount of deviation is calculated between the feature extracted from observation data obtained by an imaging apparatus and the feature in the three-dimensional model. The three-dimensional position and orientation of the object is estimated based on the amount of deviation and the reliability related to each feature extracted from the three-dimensional model.

Claims

1. A position and orientation estimation method comprising:

calculating a statistic of deviation of a geometric feature constituting a three-dimensional geometric model of the held object;

calculating a reliability for each geometric feature based on the statistic of deviation;

extracting an image feature of a captured image captured;

associating the geometric feature with the image feature;

calculating an amount of deviation between the geometric feature and the image feature; and

estimating the position and orientation of the object based on the reliability and the amount of deviation.

2. The position and orientation estimation method according to claim 1, wherein the statistic is calculated based on tolerance data of the three-dimensional geometric model

3. The position and orientation estimation method according to claim 2, wherein calculating a statistic comprises:

extracting a line segment constituting the three-dimensional geometric model;

extracting a tolerance causing a deviation of the line segment;

calculating the tolerance for each predetermined interval of the line segment; and

generating a vector of a tolerance in the maximum tolerance and taking the vector as the statistic.

4. The position and orientation estimation method according to claim 2, wherein the statistic is represented by probability distribution.

5. The position and orientation estimation method according to claim 4, wherein calculating a statistic comprises:

extracting a line segment constituting the three-dimensional geometric model;

extracting a tolerance causing a deviation of the line segment;

calculating the tolerance for each predetermined interval of the line segment; and

generating a vector of a normal distribution based on the tolerance and taking the vector as the statistic.

6. The position and orientation estimation method according to claim 2, wherein calculating a statistic comprises:

extracting a surface constituting the three-dimensional geometric model;

calculating a tolerance in the center of gravity of the surface; and

generating a vector of a tolerance in the maximum tolerance and taking the vector as the statistic.

7. The position and orientation estimation method according to claim 1, further comprising measuring a geometric feature constituting a shape of the object,

wherein calculating a statistic includes measuring the statistic based on a deviation between the measured result and the three-dimensional geometric model.

8. The position and orientation estimation method according to claim 7, wherein measuring a geometric feature includes performing measurement a plurality of times for each plurality of objects.

9. The position and orientation estimation method according to claim 7, wherein measuring a geometric feature includes performing measurement a plurality of times for each plurality of measurement positions.

10. The position and orientation estimation method according to claim 1, wherein the geometric feature is a point, line segment, or surface.

11. The position and orientation estimation method according to claim 1, wherein the reliability is calculated higher as the statistic is smaller.

12. The position and orientation estimation method according to any one of claim 1, wherein calculating the reliability is calculated using a likelihood function.

13. The position and orientation estimation method according to claim 1, further comprising inputting an approximate value of position and orientation of the object,

wherein inputting an approximate value includes:

calculating a correction value of position and orientation of the object based on the reliability, the amount of deviation, and the approximate value; and

correcting the approximate value of position and orientation of the object based on the correction value.

15. A storage medium storing a program for causing a computer to execute the position and orientation estimation method according to claim 1.

14. (canceled)

16. A position and orientation estimation apparatus comprising:

statistic calculation unit configured to calculate a statistic of deviation of a geometric feature constituting a three-dimensional geometric model of the object;

reliability calculation unit configured to calculate a reliability for each geometric feature based on the statistic of deviation;

image feature extraction unit configured to extract an image feature of a captured image captured by image capture means;

association unit configured to associate the geometric feature with the image feature;

deviation-amount calculation unit configured to calculate an amount of deviation between the geometric feature and the image feature; and

position and orientation estimation unit configured to estimate the position and orientation of the object based on the reliability and the amount of deviation.

17. The position and orientation estimation apparatus according to claim 16, further comprising the image capture unit configured to capture an image of the object.

18. The position and orientation estimation apparatus according to claim 17, wherein the image capture unit captures a range image in a real space as the captured image.