System and method for extracting corner point in space using pixel information, and robot using the system

• US 7,653,247 B2
• Filed: 09/29/2005
• Issued: 01/26/2010
• Est. Priority Date: 10/15/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Hyoung-Ki, Jung, Myung-Jin, Bang, Seok-Won, Park, Dong-Ryeol
• Primary Examiner(s): Mehta; Bhavesh M
• Assistant Examiner(s): Thirugnanam; Gandhi
• Application Number:
  US11/237,660
• Publication Number:
  US 20060083427A1
• Time in Patent Office: 1,580 Days
• Field of Search: 382/153, 382/190, 382/201, 701/245
• US Class Current: 382/201
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/20164 Salient point detection; Corner detection
• CPC Class Codes: G06T 2207/30204 Marker
• CPC Class Codes: G06T 2207/30248 Vehicle exterior or interior
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06V 20/64 Three-dimensional objects

Abstract

A system and method for extracting a corner point in a space using pixel information obtained from a camera are provided. The corner point extracting system includes a light generation module emitting light in a predetermined form (such as a plane form), an image acquisition module acquiring an image of a reflector reflecting the light emitted from the light generation module, and a control module obtaining distance data between the light generation module and the reflector using the acquired image and extracting a corner point by performing split-merge using a threshold proportional to the distance data. The threshold is a value proportional to the distance data which corresponds to pixel information of the image acquisition module.

Claims

1. A corner point extracting system comprising:

a light generator emitting light in a predetermined form;

an image acquisition device acquiring an image of a reflector reflecting the light emitted from the light generator; and

a control module obtaining pixel information of the acquired image and obtaining distance data between the light generator and the reflector using the pixel information of the acquired image and a geometrical relationship among the light generator, the reflector and the image acquisition device and obtaining a corner point by performing split-merge using a threshold proportional to the distance data, the distance data representing coordinate values of points on a plane obtained when the light generator and the reflector are viewed from above, the points being converted from pixels in the acquired image,

wherein the threshold is a value proportional to the distance data which corresponds to the pixel information obtained from the image acquisition device,

wherein split-merge is performed by connecting a line between two end points of the distance data, measuring distances between the line and each of the distance data points, performing a split of the line if the measured distance exceeds a predetermined threshold to create additional lines, continuously performing the splitting of the line to produce continuous lines until no measured distance exceeds the predetermined threshold and thereafter creating a common line to the continuous lines to merge the continuous lines.

2. The corner point extracting system of claim 1, wherein the light is laser light.

3. The corner point extracting system of claim 1, wherein the threshold is the value proportional to the distance data, the distance data corresponding to a 1 pixel distance in the image acquisition module.

4. The corner point extracting system of claim 1, wherein the threshold is proportional to |F(x_s, y_s)−

F(x_s, y_s+1)|, where x_s and y_s indicate random coordinates in the acquired image, y_s+1 is a coordinate shifted from the position y_s by 1 pixel in a y-direction, and F(a, b) is a coordinate value on a new plane, into which a coordinate value is converted using the triangulation, the coordinate value being represented by [a b]^T.

5. The corner point extracting system of claim 1, wherein the control module obtains the distance data using coordinates of the acquired image in a triangulation.

17. The corner point extracting system of claim 1, wherein the predetermined form comprises a plane form.

6. A method of extracting a corner point, comprising:

emitting light to a reflector in a predetermined form from a light generator;

acquiring an image of the reflector reflecting the light from an image acquiring device and obtaining pixel information of the acquired image;

obtaining distance data between a light emission point and the reflector using the pixel information of the acquired image and a geometrical relationship among the light generator, the reflector and the image acquiring device, the distance data representing coordinate values of points on a plane obtained when the light generator and the reflector are viewed from above, the points being converted from pixels in the acquired image; and

obtaining a corner point by performing split-merge based on a threshold proportional to the distance data,

wherein the threshold is a value proportional to the distance data which corresponds to the pixel information of the acquired image,

wherein split-merge is performed by connecting a line between two end points of the distance data, measuring distances between the line and each of the distance data points, performing a split of the line if the measured distance exceeds a predetermined threshold to create additional lines, continuously performing the splitting of the line to produce continuous lines until no measured distance exceeds the predetermined threshold and thereafter creating a common line to the continuous lines to merge the continuous lines.

7. The method of claim 6, wherein the light is laser light.

8. The method of claim 6, wherein the threshold is the value proportional to the distance data, the distance data corresponding to a 1 pixel distance in the image acquisition module.

9. The method of claim 6, wherein the threshold is proportional to |F(x_s, y_s)−

F(x_s, y_s+1)|, where x_s and y_s indicate random coordinates in the acquired image, y_s+1 is a coordinate shifted from the position y_s by 1 pixel in a y-direction, and F (a, b) is a coordinate value on a new plane, into which a coordinate value is converted using the triangulation, the coordinate value being represented by [a b]^T.

10. The method of claim 6, wherein the obtaining of the distance data includes obtaining the distance data using coordinates of the acquired image in a triangulation.

18. The method of claim 6, wherein the predetermined form comprises a plane form.

11. A mobile robot, comprising:

a corner point obtaining system acquiring an image of a reflector which reflects light emitted thereto in a predetermined form and obtaining a corner point using pixel information of the acquired image, the corner point being obtained by performing split-merge based on a threshold proportional to distance data that corresponds to the pixel information of the acquired image, the distance data being obtained between a light emission point and the reflector using the pixel information of the acquired image and a geometrical relationship among a light generation module, the reflector and an image acquisition module and representing coordinate values of points on a plane obtained when the light generator and the reflector are viewed from above, the points being converted from pixels in the acquired image;

a central control system determining a moving direction and speed of the mobile robot based on a position of the extracted corner point; and

a driving system moving the mobile robot according to the moving direction and speed determined by the central control system,

wherein split-merge is performed by connecting a line between two end points of the distance data, measuring distances between the line and each of the distance data points, performing a split of the line if the measured distance exceeds a predetermined threshold to create additional lines, continuously performing the splitting of the line to produce continuous lines until no measured distance exceeds the predetermined threshold and thereafter creating a common line to the continuous lines to merge the continuous lines.

12. The mobile robot of claim 11, wherein the corner point extracting system comprises:

the light generation module emitting the light in the plane form;

the image acquisition module acquiring the image of the reflector reflecting the light emitted from the light generation module; and

a control module obtaining the distance data between the light generation module and the reflector using the acquired image and extracting the corner point by performing the split-merge using the threshold proportional to the distance data.

13. The mobile robot of claim 12, wherein the light is laser light.

14. The mobile robot of claim 12, wherein the threshold is the value proportional to the distance data, the distance data corresponding to a 1 pixel distance in the image acquisition module.

15. The mobile robot of claim 12, wherein the threshold is proportional to |F(x_s, y_s)−

F(x_s, y_s+1)|, where x_s and y_s indicate random coordinates in the acquired image, y_s+1 is a coordinate shifted from the position y_s by 1 pixel in a y-direction, and F(a, b) is a coordinate value on a new plane, into which a coordinate value is converted using the triangulation, the coordinate value being represented by [a b]^T.

16. The mobile robot of claim 12, wherein the control module obtains the distance data using coordinates of the acquired image in a triangulation.

19. The mobile robot of claim 11, wherein the predetermined form comprises a plane form.