Determining Travel Path Features Based on Retroreflectivity

• US 20100217529A1
• Filed: 02/20/2009
• Published: 08/26/2010
• Est. Priority Date: 02/20/2009
• Status: Active Grant

• Current Assignee: HERE Global B.V. (HERE Holding Corporation)
• Original Assignee: HERE Global B.V. (HERE Holding Corporation)
• Inventors: Lu, Victor, Moghaddam, Mahsa Kamali, Kohlmeyer, Bradley Dean, Stroila, Matei Nicolai, Chen, Xin
• Granted Patent: US 8,699,755 B2
• Time in Patent Office: Days
• US Class Current: 702/5
• CPC Class Codes: G01C 3/06 Use of electric means to obtain final indication
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G09B 29/008 Touring maps or guides to public transport networks

Abstract

Systems, devices, features, and methods for determining geographic features corresponding to a travel path to develop a map database, such as a navigation database, are disclosed. For example, one method comprises emitting light from a light source, such as a LIDAR device, while on the travel path. Returning light is received based on the emitted light. The returning light is used to generate data points representing an area about the travel path. The data points are filtered as a function of a return intensity value to identify a feature associated with the travel path, in which the feature is treated with a retroreflective substance.

Claims

1. A method for determining geographic features corresponding to a road network to develop a navigation database, the method comprising:

collecting data points via a LIDAR device while driving on a road of the road network;

filtering the collected data points based on a retroreflectivity threshold; and

identifying data points that correspond to a road feature based on the filtered data points,

wherein the road feature is treated with a retroreflective substance.

2. The method of claim 1, wherein the road feature comprises a road sign or a lane marking.

3. The method of claim 1, wherein identifying the data points comprises:

determining a plane that substantially fits a portion of the filtered data points.

4. The method of claim 3, further comprising:

calculating a normal vector relative to the plane.

5. The method of claim 4, further comprising:

comparing a driving direction with the calculated normal vector.

6. The method of claim 1, wherein identifying the data points comprises:

eliminating outlier data points based on a number of neighboring data points within a specific radius.

7. The method of claim 1, wherein identifying the data points comprises:

identifying a cluster of the filtered data points; and

applying a growing algorithm to identify additional data points corresponding to the road feature.

8. The method of claim 1, further comprising:

generating a data model representing the road feature based on the identified data points; and

storing the data model in the navigation database.

9. The method of claim 8, wherein generating the data model comprises:

fitting a geometric shape to a boundary associated with the identified data points.

10. The method of claim 8, wherein generating the data model comprises:

matching the identified data points with collected video or camera data.

11. The method of claim 1, wherein identifying the data points comprises:

applying a grid to a portion of the filtered data points to determine whether the portion of the filtered data points correspond to separate road features.

21. The method of claim 1, wherein filtering the data points comprises filtering a LIDAR point cloud to remove LIDAR points having values below the return intensity value.

12. A method for determining geographic features corresponding to a travel path to develop a map database, the method comprising:

emitting light from a light source while on the travel path;

receiving returning light based on the emitted light, the returning light used to generate data points representing an area about the travel path; and

filtering the data points as a function of a return intensity value to identify a feature associated with the travel path, the feature being treated with a retroreflective material.

13. The method of claim 12, wherein the light source comprises a LIDAR device.

14. The method of claim 12, wherein the travel path comprises a road or a pedestrian pathway.

15. The method of claim 12, wherein the feature comprises a sign or marking on the travel path.

16. The method of claim 12, wherein the retroreflective substance comprises a retroreflective paint or retroreflective sheeting.

17. The method of claim 12, wherein emitting the light comprises transmitting a laser signal in a near infrared spectrum.

18. The method of claim 12, further comprising:

collecting video images of path features.

19. The method of claim 12, further comprising:

determining a position of a device supporting the light source.

20. The method of claim 19, wherein determining a position of the device comprises using a GPS system supported by the device.

22. A method for determining a geographic feature on a travel path to develop a map database, the method comprising:

collecting data points via a laser device while moving on the travel path;

extracting data points representing a path surface of the travel path from the collected data points;

filtering the extracted data points based on a return intensity threshold; and

identifying data points that correspond to a marking on the travel path based on the filtered data points.

23. The method of claim 22, wherein the marking comprises a road lane marking.

24. The method of claim 22, wherein extracting the data points representing the path surface comprises:

calculating an average ground elevation of the travel path.

25. The method of claim 24, further comprising:

determining borders of the travel path based on the average ground elevation.

26. The method of claim 22, further comprising:

generating a data model of the marking based on the identified data points; and

storing the data model in the map database.

27. A system for determining geographic features corresponding to a path to develop a navigation database, the system comprising:

a transportation device; and

a LIDAR device supported by the transportation device, the LIDAR device configured to collect data points corresponding to the path,

wherein a path feature is identified by thresholding the collected data points as a function of retroreflectivity.

28. The system of claim 27, wherein the transportation device comprises a vehicle.

29. The system of claim 27, wherein the transportation device comprises a device configured to be carried by a pedestrian.

30. A computer-readable medium configured to store a computer program that performs a method of determining geographic features corresponding to a travel path, the method comprising:

receiving collected light data representing an area about the travel path, the collected light data configured in a data point cloud;

identifying, in the data point cloud, data representing a feature associated with the travel path as a function of a return intensity value, the feature being treated with a retroreflective substance; and

generating a data model of the feature based on the identified data.