VISUAL NAVIGATION SYSTEM AND METHOD BASED ON STRUCTURED LIGHT

• US 20090118890A1
• Filed: 02/15/2008
• Published: 05/07/2009
• Est. Priority Date: 11/05/2007
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Wu, Chao-Chi, Chen, Yao-Jiunn, Lin, Yen-Chun
• Granted Patent: US 8,244,403 B2
• Time in Patent Office: Days
• US Class Current: 701/28
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means

Abstract

A visual navigation system and method based on structured light are provided. The visual navigation system at least includes at least one projector for generating a specific path pattern formed by structured light, and a visual server. In addition to facilitating the visual navigation system to detect an obstacle, the pattern formed by the structured light provides a specific path pattern followed by robots during the navigation. In the visual navigation method, when detecting the obstacle, the visual server routes a virtual path and issues a movement-control command to the robots, which in turn follow the virtual path. The present invention is capable of raising the accuracy for the robot navigation and reducing operation burden of the visual server by using the structured light to guide the robots.

Claims

1. A visual navigation system based on structured light, comprising:

a projector, constructed in an environment, for projecting the structured light into a navigation space to form a specific path pattern;

an image capture device, constructed in the environment, for capturing an image in the navigation space;

a robot, moving along the specific path pattern; and

a visual server, for receiving the image in the navigation space transmitted by the image capture device, so as to identify the position of the robot in the image, and confirming a position of an obstacle from a distorted portion of the specific path pattern in the image, and a virtual path neighbouring the obstacle is routed;

wherein when the robot moves along the specific path pattern to reach a place neighbouring the obstacle, the visual server issues a navigation instruction to the robot to make the robot follow the virtual path, and after the robot'"'"'s moving along virtual path is finished, the robot continues moving along the specific path pattern.

2. The visual navigation system based on structured light according to claim 1, wherein the image capture device and the projector are disposed at the same side or other opposite positions in the environment.

3. The visual navigation system based on structured light according to claim 1, wherein the number of the projector is more than one, and the projectors are constructed at the same side or other opposite positions in the environment.

4. The visual navigation system based on structured light according to claim 3, wherein a reflector is further installed in the environment, for reflecting the structured light projected by one of the projectors into the navigation space, such that the reflected light together with specific path patterns respectively projected by the other projectors forms a complete path pattern large enough for covering the navigation space.

5. The visual navigation system based on structured light according to claim 3, wherein as the specific path patterns respectively projected from the projectors together form a combined path pattern large enough for covering the navigation space around the obstacle, the obstacle does not block the projection of the structured light due to the volume thereof to result in a region without the combined path pattern nearby.

6. The visual navigation system based on structured light according to claim 5, wherein the number of the reflector is more than one.

7. The visual navigation system based on structured light according to claim 1, wherein the robot senses the specific path pattern through an optical sensor or an image sensor, and thus the robot moves along the specific path pattern.

8. A visual navigation method based on structured light, comprising:

generating a specific path pattern formed by structured light in a navigation space through a projection of a projector;

capturing an image in the navigation space;

detecting an obstacle according to a distorted portion of the specific path pattern in the image, wherein if no obstacle exists, a robot moves along the specific path pattern in the navigation space;

if an obstacle exists, a portion of the specific path pattern in the image distorted due to the obstacle is eliminated and a virtual boundary neighbouring the obstacle is set, and a virtual path is routed;

determining whether a target point is reached, if yes, the navigation is finished;

if not, it is determined whether the previously routed virtual path is met;

wherein if the virtual path is met, the robot follows the virtual path;

if not, the robot continues moving along the specific path pattern, and the above steps of determining “

whether a target point is reached” and

“

whether the previously routed virtual path is met”

are performed repeatedly till the robot reaches the target point.

9. The method according to claim 8, wherein the projection and capturing of the image are performed at the same side or other opposite positions in the environment.

10. The method according to claim 8, wherein the structured light comes from an optical projector or any other optical projection devices.

11. The method according to claim 8, wherein the detection of an obstacle, the routing of a path, or other operations is performed by a computer or any other embedded operating devices.

12. The method according to claim 8, wherein the robot senses the specific path pattern through an optical sensor or an image sensor, and thus the robot moves along the specific path pattern.

13. The method according to claim 8, wherein a distance between the virtual path and the virtual boundary of the obstacle is at least the same as that from a heart of the robot to an outermost shell thereof, or determined by a distance between several marks attached on the robot, or obtained by other algorithms for routing a path.

14. A visual navigation method based on structured light, comprising:

generating a plurality of specific path patterns formed by structured light in a navigation space through projection of a plurality of projectors;

capturing a pattern image in the navigation space;

detecting an obstacle according to a distorted portion of the specific path patterns in the image, wherein if no obstacle exists, a robot moves along the specific path patterns in the navigation space;

if an obstacle exists, a portion of the specific path patterns in the image distorted due to the obstacle is eliminated and a virtual boundary neighbouring the obstacle is set, and a virtual path is routed;

determining whether a target point is reached, if yes, the navigation is finished;

if not, it is determined whether the previously routed virtual path is met;

wherein if the virtual path is met, the robot follows the virtual path;

if not, the robot continues moving along the specific path patterns, and the above steps of determining “

whether a target point is reached” and

“

whether the previously routed virtual path is met”

are performed repeatedly till the robot reaches the target point;

the specific path patterns are overlapped or are not overlapped with each other, and if the specific path patterns are overlapped with each other, each specific path pattern has a different colour.

15. The method according to claim 14, wherein if the specific path patterns are not overlapped with each other, the projectors respectively project towards the same region in the navigation space at different time or project towards different separated regions in the navigation space at the same time.

16. The method according to claim 15, wherein as different separated regions in the navigation space form a combined path pattern large enough for covering the navigation space around the obstacle, the obstacle does not block the projection of the structured light due to the volume thereof to result in a region without the combined path pattern nearby.

17. The method according to claim 14, wherein the projection and capturing of the image are performed at the same side or other opposite positions in the environment.

18. The method according to claim 14, wherein the projectors are constructed at the same side or other opposite positions in the environment.

19. The method according to claim 18, wherein the projectors are optical projectors or any other optical projection devices.

20. The method according to claim 14, wherein a reflector is further installed in the environment, for reflecting the structured light projected by one of the projectors into the navigation space.

21. The method according to claim 20, wherein the number of the reflector is more than one.

22. The method according to claim 14, wherein the detection of the obstacle, the routing of the visual path, or other operations is performed by a computer or any other embedded operating devices.

23. The method according to claim 14, wherein the robot senses the specific path patterns through an optical sensor or an image sensor, and thus the robot moves along the specific path patterns.

24. The method according to claim 14, wherein the structured light is generated continuously, or intermittently, or only once.

25. The method according to claim 14, wherein a distance between the virtual path and the virtual boundary of the obstacle is at least the same as that from a heart of the robot to an outermost shell thereof, or determined by a distance between several marks attached on the robot, or obtained by other algorithms for routing a path.