Robot cleaner and method for controlling the same

• US 10,255,501 B2
• Filed: 03/27/2018
• Issued: 04/09/2019
• Est. Priority Date: 10/14/2014
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Noh, Dongki, Kim, Yeonsoo, Baek, Seungmin
• Primary Examiner(s): Bitar, Nancy
• Application Number:
  US15/937,078
• Publication Number:
  US 20180218216A1
• Time in Patent Office: 378 Days
• Field of Search: None
• CPC Class Codes: B25J 9/1664 characterised by motion, path, trajectory planning
• CPC Class Codes: B25J 9/1676 Avoiding collision or forbidden zones
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G05D 1/0248 in combination with a laser lasers per se H01S
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: G06T 7/74 involving reference images or patches
• CPC Class Codes: G06V 20/10 Terrestrial scenes scenes under surveillance with static cameras G06V20/52; scenes perceived from the exterior of a vehicle G06V20/56; scenes perceived from the interior of a vehicle G06V20/59
• CPC Class Codes: Y10S 901/01 Mobile robot

Abstract

A method for controlling a robot cleaner configured to project light of a predetermined pattern to a floor of an area in front thereof in a specific direction and to acquire an image of the area to which the light is projected, according to the present disclosure, includes: (a) acquiring a front view image of the robot cleaner; (b) detecting the pattern from the image acquired in (a); and (c) discriminating a pattern formed by reflected light from a pattern formed by light directly projected from the robot cleaner, from among patterns indicated in the acquired image, on the basis of geometrical characteristics defined by a projection direction of the light and the direction of an optical axis in which the image is acquired when two or more patterns are detected from the image.

Claims

1. A method for controlling a robot cleaner configured to project light of a predetermined pattern to a floor of an area in front of the robot cleaner in a downward direction and to acquire an image of the area to which the light is projected, comprising:

(a) acquiring an image of an area in front of the robot cleaner, wherein the acquired image including information regarding at least a first pattern and a second pattern, the first and second pattern being vertically aligned with regard to the acquired image, the first pattern formed by light directly projected from the robot cleaner, and the second pattern formed by light projected from the robot cleaner and then reflected to form the second pattern;

(b) detecting at least the first and second patterns from the acquired image;

(c) discriminating, at a controller of the robot cleaner, the first pattern from the second pattern based on geometrical characteristics defined by a projection direction of the light and a direction of an optical axis in which the image is acquired, wherein discriminating the first pattern from the second pattern includes determining the first pattern as being a valid pattern and determining the second pattern as being reflected light, wherein the discriminating based on the geometrical characteristics defined by the projection direction of the light and the direction of the optical axis is performed at the controller of the robot cleaner,

three-dimensionally configuring obstacle information around the robot cleaner based at least on the detected valid pattern; and

controlling movement of the robot cleaner based on the three-dimensionally configured obstacle information.

2. The method of claim 1, wherein, when a position of a third pattern formed by light directly projected to the floor is defined as a reference position in the acquired image, step (c) comprises selecting a pattern detected at the reference position as the first pattern when one of the two or more patterns is detected at the reference position and at least one other pattern is detected from a region above the reference position.

3. The method of claim 1, wherein, when a position of a third pattern formed by light directly projected to the floor is defined as a reference position in the acquired image, step (c) comprises selecting a pattern detected from a region above the reference position as the first pattern when patterns are respectively detected from the region above the reference position and a region below the reference position.

4. The method of claim 3, comprising obtaining a distance to an object based on the first pattern.

5. The method of claim 4, wherein the obtaining of the distance includes obtaining the distance to the object based on a location relation between the reference position and the first pattern in the acquired image.

6. The method of claim 5, wherein the obtaining of the distance includes determining that the distance to the object is shorter as the distance between the reference position and the first pattern increases.

7. The method of claim 2, further comprising updating the reference position,

wherein the updating of the reference position comprises:

(d-1) acquiring an image of an area in front of the robot cleaner;

(d-2) detecting a fourth pattern formed by light directly projected to the floor from the robot cleaner from the image acquired in step (d-1);

(d-3) comparing a distance between the fourth pattern and the reference position with a predetermined allowable distance; and

(d-4) updating the reference position to a position of the fourth pattern based on a comparison result in step (d-3).

8. The method of claim 7, wherein the updating the reference position further comprises:

(d-5) moving the robot cleaner upon determining that the distance obtained in step (d-2) is greater than the allowable distance in step (d-2);

(d-6) acquiring an image of an area in front of the robot cleaner at a changed position of the robot cleaner;

(d-7) detecting a fifth pattern formed by light directly projected to the floor from the robot cleaner from the image acquired in step (d-6);

(d-8) comparing a position of the fifth pattern with a position of the fourth pattern detected in step (d-2); and

(d-9) updating the reference position to the position of the fourth pattern on the basis of a comparison result in step (d-8).

9. The method of claim 8, wherein step (d-9) comprises updating the reference position to the position of the fourth pattern when the position of the fifth pattern is the same as the position of the fourth pattern.

10. The method of claim 1, wherein when a position of a third pattern formed by the light directly projected to the floor is defined as a reference position in the acquired image,

(e) estimating a fourth position at which the boundary between the object and the floor will be detected on the basis of the reference position and a position of a fourth pattern generated by light directly projected to an object located in front of the robot cleaner;

and

(f) selecting a boundary from patterns detected in step (b) on the basis of the fourth position.

11. The method of claim 10, wherein step (f) comprises selecting a pattern closest to the fourth position from the patterns detected in step (b).

12. The method of claim 1, wherein the acquiring of the image includes acquiring the image including the first pattern and the second pattern by using a camera at the robot cleaner.

13. The method of claim 1, wherein the valid pattern is a pattern generated by light directly projected onto a surface from a projection device of the robot cleaner, and the second pattern is a pattern from light projected from the projection device and then reflected by the surface to form the second pattern.

14. A method for controlling a robot cleaner configured to project light in front of the robot cleaner in a downward direction and to acquire an image of the area to which the light is projected, comprising:

acquiring an image of an area in front of the robot cleaner, wherein the acquired image including information regarding at least a first pattern and a second pattern, the first and second pattern being vertically aligned with regard to the acquired image, the first pattern formed by light directly projected from the robot cleaner, and the second pattern formed by light projected from the robot cleaner and then reflected to form the second pattern;

detecting at least the first and second patterns from the acquired image;

discriminating, at a controller of the robot cleaner, the first pattern from the second pattern based on geometrical characteristics defined by a projection direction of the light and a direction of an optical axis in which the image is acquired when two or more patterns are detected from the image, wherein discriminating the first pattern from the second pattern includes determining the first pattern as being a valid pattern and determining the second pattern as being reflected light, wherein the discriminating based on the geometrical characteristics defined by the projection direction of the light and the direction of the optical axis is performed at the controller of the robot cleaner,

three-dimensionally configuring obstacle information around the robot cleaner based at least on the detected valid pattern; and

controlling movement of the robot cleaner based on the three-dimensionally configured obstacle information.

15. The method of claim 14, wherein when a position of a third pattern formed by light projected to a floor is defined as a reference position in the acquired image, the discriminating of the first pattern from the second pattern includes selecting a pattern detected at the reference position as the first pattern when one of the two or more patterns is detected at the reference position and at least one other pattern is detected from a region above the reference position.

16. The method of claim 14, wherein when a position of a third pattern formed by light projected to a floor is defined as a reference position in the acquired image, the discriminating of the first pattern from the second pattern includes selecting a pattern detected from a region above the reference position as the first pattern when patterns are respectively detected from the region above the reference position and a region below the reference position.

17. The method of claim 16, comprising obtaining a distance to an object based on the first pattern.

18. The method of claim 17, wherein the distance to the object is obtained based on a location relation between the reference position and the first pattern in the acquired image.

19. The method of claim 18, wherein the obtaining of the distance to the object includes determining that the distance to the object is shorter as the distance between the reference position and the first pattern increases.

20. The method of claim 15, comprising updating the reference position, wherein the updating of the reference position includes:

acquiring an image of an area in front of the robot cleaner;

detecting a fourth pattern formed by light projected to a floor from the robot cleaner from the acquired image;

comparing a distance between the fourth pattern and the reference position with a predetermined allowable distance; and

updating the reference position to a position of the fourth pattern based on a result of the comparing.