Apparatus and method for detecting obstacles

• US 20050088642A1
• Filed: 05/15/2003
• Published: 04/28/2005
• Est. Priority Date: 05/15/2002
• Status: Active Grant

• Current Assignee: Carnegie Mellon University
• Original Assignee: Carnegie Mellon University
• Inventors: Batavia, Parag, Singh, Sanjiv
• Granted Patent: US 7,092,075 B2
• Time in Patent Office: Days
• US Class Current: 356/5.10
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 17/93 for anti-collision purposes
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver

Abstract

A method for detecting an obstacle in a spatial area is disclosed. The method includes scanning the spatial area, classifying each reflection point in the spatial area as one of an obstacle reflection point and a non-obstacle reflection point, fusing the obstacle reflection points, and generating statistics associated with the obstacle.

Claims

1. A method for detecting an obstacle in a spatial area, the method comprising:

scanning the spatial area;

classifying each reflection point in the spatial area as one of an obstacle reflection point and a non-obstacle reflection point;

fusing the obstacle reflection points; and

generating statistics associated with the obstacle.

2. The method of claim 1, wherein scanning the spatial area includes scanning the spatial area in elevation with a single axis laser range finder while sweeping the single axis laser range finder in azimuth.

3. The method of claim 2, wherein scanning the spatial area in elevation with the single axis range finder while sweeping the single axis range finder in azimuth includes scanning the spatial area in elevation with a single axis laser range finder at a first frequency while sweeping the single axis laser range finder in azimuth at a second frequency, wherein the first frequency is greater than the second frequency.

4. The method of claim 3, wherein scanning the spatial area in elevation includes emitting a succession of light pulses and receiving a succession of reflected light pulses.

5. The method of claim 4, wherein emitting the succession of light pulses includes emitting the succession of light pulses over a predetermined angular range.

6. The method of claim 3, wherein sweeping the single axis laser range finder in azimuth includes sweeping the single axis laser range finder over a predetermined angular range.

7. The method of claim 1, wherein classifying each reflection point in the spatial area as one of an obstacle reflection point and a non-obstacle reflection point includes classifying each reflection point from an individual scan as one of an obstacle reflection point and a non-obstacle reflection point.

8. The method of claim 7, wherein classifying each reflection point from the individual scan includes generating a scan line.

9. The method of claim 8, wherein generating the scan line includes converting the reflection points to Cartesian coordinates in a scanner-centric frame.

10. The method of claim 8, wherein classifying each reflection point from the individual scan includes determining a gradient along a dimension of the scan line.

11. The method of claim 10, wherein classifying each reflection point from the individual scan includes classifying each reflection point from the individual scan based on a gradient threshold.

12. The method of claim 11, wherein classifying each reflection point in the spatial area includes transforming the obstacle reflection points to a common coordinate frame at a predetermined rate.

13. The method of claim 1, wherein fusing the obstacle reflection points includes defining a cluster of obstacle reflection points.

14. The method of claim 13, wherein defining the cluster of obstacle reflection points includes defining the cluster based on nearest neighbor criterion.

15. The method of claim 13, wherein defining the cluster of obstacle reflection points includes defining more than one cluster of obstacle reflection points.

16. The method of claim 1, wherein generating statistics associated with the obstacle includes defining a height of the obstacle.

17. The method of claim 1, wherein generating statistics associated with the obstacle includes defining a width of the obstacle.

18. The method of claim 1, wherein generating statistics associated with the obstacle includes defining a distance the obstacle is positioned from a reference point.

19. The method of claim 1, wherein generating statistics associated with the obstacle includes defining an angle the obstacle is positioned relative to a reference point.

20. The method of claim 1, wherein generating the statistics associated with the obstacle includes filtering the obstacle.

21. The method of claim 20, wherein filtering the obstacle includes filtering the obstacle based on a size threshold.

22. A computer-readable medium having stored thereon a set of instructions which, when executed by a processor, cause the processor to:

classify data as one of an obstacle and a non-obstacle;

fuse the obstacle data; and

generate statistics associated with the obstacle.

23. An apparatus for detecting an obstacle in a spatial area, the apparatus comprising:

a single axis laser range finder configured for scanning the spatial area in elevation;

an assembly connected to the single axis laser range finder, wherein the assembly is for sweeping the single axis laser range finder in azimuth;

a synchronizer in communication with the single axis laser range finder and the assembly; and

a processor in communication with the synchronizer, wherein the processor includes;

a classifying module for classifying data received from the synchronizer as being representative of one of an obstacle and a non-obstacle;

a fusing module for fusing the data representative of the obstacle; and

a generation module for generating statistics associated with the obstacle.

24. The apparatus of claim 23, wherein the assembly includes a servo-motor.

25. The apparatus of claim 23, wherein the assembly includes an encoder for determining a sweep angle of the single axis laser range finder.

26. The apparatus of claim 23, wherein the assembly includes a sensor for sensing pitch information associated with the single axis laser range finder.