MOBILE ROBOT AND CONTROLLING METHOD OF THE SAME

• US 20120051595A1
• Filed: 08/26/2011
• Published: 03/01/2012
• Est. Priority Date: 08/31/2010
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Na, Sangik, Kim, Yiebin, Baek, Seungmin, Lee, Seongsu
• Granted Patent: US 8,781,164 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30

Abstract

Disclosed are a mobile robot and a controlling method of the same. The mobile robot is capable of reducing a position recognition error and performing a precise position recognition even in the occurrence of a change of external illumination, through geometric constraints, when recognizing its position with using a low quality camera (e.g., camera having a low resolution). Furthermore, feature points may be extracted from images detected with using a low quality camera, and the feature points may be robustly matched with each other even in the occurrence of a change of external illumination, through geometric constraints due to the feature lines. This may enhance the performance of the conventional method for recognizing a position based on a camera susceptible to a illumination change, and improve the efficiency of a system.

Claims

1. A mobile robot, comprising:

an image detection unit configured to detect one or more images in a vicinity of the mobile robot;

a straight line extraction unit configured to extract one or more straight lines from at least one of the one or more images;

a feature line extraction unit configured to extract, from the one or more straight lines, one or more feature lines toward a center of the at least one of the one or more images;

a feature point extraction unit configured to extract one or more feature points from the at least one of the one or more images; and

a control unit configured to match feature points of at least a subset of the one or more images with feature points of the at least one of the one or more images, and to recognize a position of the mobile robot based on a result of the feature point matching.

2. The mobile robot of claim 1, further comprising a storage unit configured to store therein image information including image information of the one or more images detected by the image detection unit, the one or more feature lines extracted by the feature line extraction unit, and the one or more feature points extracted by the feature point extraction unit.

3. The mobile robot of claim 2, wherein the control unit is configured to match a feature point stored in the storage unit with a feature point of an image detected by the image detection unit, and to recognize a position of the mobile robot based on a result of the feature point matching.

4. The mobile robot of claim 1, wherein the feature point extraction unit identifies an intersection point between one of the one or more feature lines and one of the one or more straight lines as a feature point.

5. The mobile robot of claim 4, wherein the identified feature point includes feature point information consisting of a position, an orientation and a descriptor of the identified feature point on the image, and the descriptor indicates extraction information of the identified feature point, wherein the extraction information is information indicating how the feature point has been extracted or how the feature point has existed in the image.

6. The mobile robot of claim 5, wherein the control unit calculates a similarity between pluralities of identified feature points based on the feature point information of the pluralities of identified feature points, and recognizes a position of the mobile robot based on feature points having a largest similarity therebetween.

7. The mobile robot of claim 1, further comprising:

a driving unit configured to move the mobile robot by driving wheels provided on the robot; and

a moving distance measuring unit connected to the wheels, and configured to measure a moving distance of the mobile robot.

8. The mobile robot of claim 1, wherein the image detection unit is implemented as an upper camera installed above the mobile robot, and configured to detect an upper image by capturing an upper side.

9. The mobile robot of claim 1, further comprising an obstacle detection unit configured to detect a peripheral obstacle, and to output obstacle information,

wherein the control unit is configured to create a map by using the obstacle information, or by using the obstacle information and the position of the mobile robot.

10. A method for controlling a mobile robot, the method comprising:

an image detection step of detecting, by an image detecting unit of the mobile robot, one or more images in a vicinity of the mobile robot;

a straight line extraction step of extracting one or more straight lines from at least one of the one or more images;

a feature line extraction step of extracting, from the one or more straight lines, one or more feature lines toward a center of the at least one of the one or more images;

a feature point extraction step of extracting one or more feature points from the at least one of the one or more images;

a feature point matching step of matching feature points with each other; and

a position recognition step of recognizing a position of the mobile robot based on a result of the feature point matching.

11. The method of claim 10, further comprising an image information storage step of storing therein image information including image information of the one or more images, the one or more feature lines, and the one or more feature points.

12. The method of claim 11, wherein in the position recognition step, a stored feature point is matched with a feature point of the at least one of the one or more images, and a position of the mobile robot is recognized based on a result of the feature point matching.

13. The method of claim 10, wherein the feature point is identified as an intersection point between one of the one or more feature lines and one of the one or more straight lines.

14. The method of claim 13, wherein the feature point includes feature point information comprising a position, an orientation and a descriptor of the feature point on the image, and the descriptor indicates extraction information of the feature point, wherein the extraction information is information indicating how the feature point has been extracted or how the feature point has existed in the image.

15. The method of claim 14, wherein the position recognition step includes:

calculating each similarity between the feature points based on the feature point information;

comparing the similarities with each other; and

recognizing a position of the mobile robot based on feature points having a largest similarity therebetween.

16. The method of claim 10, further comprising a moving distance measuring step of measuring a moving distance of the mobile robot.

17. The method of claim 10, further comprising:

an obstacle detecting step of detecting an obstacle in the vicinity of the mobile robot, and outputting obstacle information; and

a map creating step of creating a map based on the obstacle information.

18. The method of claim 17, further comprising correcting the map based on the position of the mobile robot.

19. A non-transient computer readable storage medium having an algorithm stored therein, the algorithm configured to cause a processor of a mobile robot to perform:

an image detection step of detecting one or more images by capturing a periphery;

a straight line extraction step of extracting one or more straight lines from the image;

a feature line extraction step of extracting, from the straight lines, one or more feature lines toward a center of the image;

a feature point extraction step of extracting one or more feature points from the image;

a feature point matching step of matching the feature points with each other; and

a position recognition step of recognizing a position of the mobile robot based on a result of the feature point matching.

20. The non-transient computer readable storage medium of claim 19, wherein the algorithm is further configured to cause the processor of the mobile robot to perform:

an obstacle detecting step of detecting a peripheral obstacle, and outputting obstacle information; and

a map creating step of creating a map based on the obstacle information.