Methods and systems for detection of reflective markers at long range

• US 9,080,866 B1
• Filed: 06/26/2013
• Issued: 07/14/2015
• Est. Priority Date: 06/26/2013
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Zhu, Jiajun, Droz, Pierre-yves, Wachter, Luke, Dowdall, Jonathan Baldwin, Iordache, Dorel Ionut
• Primary Examiner(s): NGUYEN, SANG H
• Application Number:
  US13/927,518
• Time in Patent Office: 748 Days
• Field of Search: 356600-625, 356/4.01, 701/70, 701/34, 701/446, 701/301, 701/23, 701/26, 702/3, 702/94, 702/95, 702/97, 702/134, 702/155, 702/158
• US Class Current: 1/1
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road
• CPC Class Codes: G08G 5/0026 located on the ground
• CPC Class Codes: G08G 5/065 Navigation or guidance aids, e.g. for taxiing or rolling

Abstract

Example methods and systems for detecting reflective markers at long range are provided. An example method includes receiving laser data collected from successive scans of an environment of a vehicle. The method also includes determining a respective size of the one or more objects based on the laser data collected from respective successive scans. The method may further include determining, by a computing device and based at least in part on the respective size of the one or more objects for the respective successive scans, an object that exhibits a change in size as a function of distance from the vehicle. The method may also include determining that the object is representative of a reflective marker. In one example, a computing device may use the detection of one reflective marker to help detect subsequent reflective markers that may be in a similar position.

Claims

1. A method comprising:

receiving laser data collected from successive scans of an environment of a vehicle, wherein the laser data includes a plurality of laser data points that are associated with one or more objects in the environment;

determining a respective size of the one or more objects based on the laser data collected from respective successive scans;

determining, by a computing device based at least in part on the respective size of the one or more objects for the respective successive scans, an object that exhibits a decrease in size in the respective successive scans above a threshold as the vehicle travels closer to the object; and

based at least in part on determining that the object exhibits the decrease in size in the respective successive scans above the threshold as the vehicle travels closer to the object, determining that the object is representative of a reflective marker.

2. The method of claim 1, further comprising:

determining an intensity of the plurality of laser data points; and

wherein determining the respective size of the one or more objects based on the laser data collected from respective successive scans comprises;

determining the respective size of the one or more objects for the plurality of laser data points having an intensity above a threshold level.

3. The method of claim 1, further comprising determining to disregard respective laser data corresponding to the object representative of the reflective marker for obstacle avoidance functionality.

4. The method of claim 1, wherein the vehicle is configured to operate in an autonomous mode.

5. The method of claim 1, further comprising determining, based on determining that the object is representative of a reflective marker, a lane position of the vehicle.

6. The method of claim 1, further comprising determining subsequent reflective markers based at least in part on prior received respective laser data corresponding to the object representative of the reflective marker.

7. A system, comprising:

at least one processor; and

a memory having stored thereon instructions that, upon execution by the at least one processor, cause the system to perform functions comprising;

receiving laser data collected from successive scans of an environment of a vehicle, wherein the laser data includes a plurality of laser data points that are associated with one or more objects in the environment;

determining a respective size of the one or more objects based on the laser data collected from respective successive scans;

determining, based at least in part on the respective size of the one or more objects for the respective successive scans, an object that exhibits a decrease in size in the respective successive scans above a threshold as the vehicle travels closer to the object; and

based at least in part on determining that the object exhibits the decrease in size in the respective successive scans above the threshold as the vehicle travels closer to the object, determining that the object is representative of a reflective marker.

8. The system of claim 7, wherein the functions further comprise:

determining an intensity of the plurality of laser data points; and

wherein determining the respective size of the one or more objects based on the laser data collected from respective successive scans comprises;

determining the respective size of the one or more objects for the plurality of laser data points having an intensity above a threshold level.

9. The system of claim 7, wherein the functions further comprise:

determining to disregard respective laser data corresponding to the object representative of the reflective marker for obstacle avoidance functionality.

10. The system of claim 7, wherein the vehicle is configured to operate in an autonomous mode.

11. The system of claim 7, wherein the functions further comprise determining, based on determining that the object is representative of a reflective marker, a lane position of the vehicle.

12. The system of claim 7, wherein the functions further comprise determining subsequent reflective markers based at least in part on prior received respective laser data corresponding to the object representative of the reflective marker.

13. A non-transitory computer readable medium having stored thereon instructions that, upon execution by a computing device, cause the computing device to perform functions comprising:

receiving laser data collected from successive scans of an environment of a vehicle, wherein the laser data includes a plurality of laser data points that are associated with one or more objects in the environment;

determining a respective size of the one or more objects based on the laser data collected from respective successive scans;

determining, based at least in part on the respective size of the one or more objects for the respective successive scans, an object that exhibits a decrease in size in the respective successive scans above a threshold as the vehicle travels closer to the object; and

based at least in part on determining that the object exhibits the decrease in size in the respective successive scans above the threshold as the vehicle travels closer to the object, determining that the object is representative of a reflective marker.

14. The non-transitory computer readable medium of claim 13, wherein the functions further comprise:

determining an intensity of the plurality of laser data points; and

wherein determining the respective size of the one or more objects based on the laser data collected from respective successive scans comprises;

determining the respective size of the one or more objects for the plurality of laser data points having an intensity above a threshold level.

15. The non-transitory computer readable medium of claim 13, wherein determining that the object is representative of a reflective marker includes determining that the object is representative of a reflective marker.

16. The non-transitory computer readable medium of claim 13, wherein the functions further comprise determining, based on determining that the object is representative of a reflective marker, a lane position of the vehicle.

17. The non-transitory computer readable medium of claim 13, wherein the functions further comprise determining subsequent reflective markers based at least in part on prior received respective laser data corresponding to the object representative of the reflective marker.