Wide-view LIDAR with areas of special attention

• US 9,983,590 B2
• Filed: 06/01/2016
• Issued: 05/29/2018
• Est. Priority Date: 09/26/2012
• Status: Active Grant

• Current Assignee: Waymo LLC (Alphabet Inc.)
• Original Assignee: Waymo LLC (Alphabet Inc.)
• Inventors: Templeton, Bradley, Droz, Pierre-yves, Zhu, Jiajun
• Primary Examiner(s): Cass, Jean Paul
• Application Number:
  US15/170,470
• Publication Number:
  US 20160274589A1
• Time in Patent Office: 727 Days
• Field of Search: None
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• 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: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4865 Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak peak detection in noise, signal conditioning G01S7/487
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means

Abstract

A system and method include scanning a light detection and ranging (LIDAR) device through a range of orientations corresponding to a scanning zone while emitting light pulses from the LIDAR device. The method also includes receiving returning light pulses corresponding to the light pulses emitted from the LIDAR device and determining initial point cloud data based on time delays between emitting the light pulses and receiving the corresponding returning light pulses and the orientations of the LIDAR device. The initial point cloud data has an initial angular resolution. The method includes identifying, based on the initial point cloud data, a reflective feature in the scanning zone and determining an enhancement region and an enhanced angular resolution for a subsequent scan to provide a higher spatial resolution in at least a portion of subsequent point cloud data from the subsequent scan corresponding to the reflective feature.

Claims

1. A method comprising:

scanning a light detection and ranging (LIDAR) device through a range of orientations corresponding to a scanning zone while emitting light pulses from the LIDAR device according to an initial angular resolution, wherein the initial angular resolution corresponds to a first angular separation between each successive pulse emitted from the LIDAR device;

receiving returning light pulses corresponding to the light pulses emitted from the LIDAR device;

determining initial point cloud data based on time delays between emitting the light pulses and receiving the corresponding returning light pulses and the orientations of the LIDAR device, wherein the initial point cloud data has an initial angular resolution;

identifying, based on the initial point cloud data, a reflective feature in the scanning zone;

locating at least one edge of the reflective feature;

based on the located at least one edge of the reflective feature, determining;

(i) an enhancement region that corresponds to the reflective feature, and (ii) an enhanced angular resolution for a subsequent scan, wherein the enhanced angular resolution corresponds to a second angular separation between each successive pulse emitted from the LIDAR device, wherein the second angular separation is less than the first angular separation, and wherein the enhanced angular resolution is determined so as to provide a higher spatial resolution in at least a portion of subsequent point cloud data from the subsequent scan, wherein the portion corresponds to the determined enhancement region.

2. The method according to claim 1, further comprising, during the subsequent scan, scanning the LIDAR device through a subsequent range of orientations corresponding to at least the enhancement region such that the portion of the subsequent point cloud data corresponding to the reflective feature has the higher spatial resolution.

3. The method according to claim 2, wherein the scanning the LIDAR device during the subsequent scan is initiated responsive to determining, based on the initial point cloud data, that the reflective feature is located at a distance exceeding a threshold distance.

4. The method according to claim 1, wherein identifying the reflective feature in the scanning zone is based on detecting a discontinuity in distances to the LIDAR device of points in the initial point cloud data that are angularly adjacent, with respect to the LIDAR device.

5. The method according to claim 1, wherein identifying the reflective feature further comprises identifying a reflective feature in motion based on the initial point cloud data.

6. The method according to claim 5, further comprising predicting a position of the reflective feature in motion, based on one or more previous point cloud data indicating previous positions of the reflective feature in motion, wherein a position of the enhancement region is determined based on the predicted position of the reflective feature in motion.

7. The method according to claim 1, wherein the LIDAR device is configured to complete a scan of the entire scanning zone during a scanning interval, and wherein the subsequent scan is initiated during a subsequent scanning interval based on information indicative of the reflective feature received during the scanning interval.

8. The method according to claim 2, further comprising analyzing the initial point cloud data and the subsequent point cloud data to identify one or more obstacles in the scanning zone interfering with a current path of an autonomous vehicle associated with the LIDAR device;

determining a modified path of the autonomous vehicle that avoids the identified one or more obstacles; and

causing the autonomous vehicle to navigate along the modified path.

9. The method of claim 1, wherein identifying, based on the initial point cloud data, a reflective feature in the scanning zone comprises defining a bounding region encompassing the reflective feature.

19. The method of claim 9, wherein the enhancement region is defined near edges of the bounding region.

10. An autonomous vehicle system comprising:

a light detection and ranging (LIDAR) device including;

a light source configured to be scanned through a range of orientations directed to a scanning zone while emitting light pulses; and

a light detector configured to receive returning light pulses reflected from features in the scanning zone, if any, each of the returning light pulses corresponding to an emitted light pulse; and

a controller configured to;

cause the LIDAR device to scan the scanning zone while emitting light pulses at a first pulse rate;

receive information from the LIDAR device indicative of the time delays between the emission of the light pulses and the reception of the corresponding returning light pulses;

determine, based on the time delays and orientations of the LIDAR device associated with each time delay, initial point cloud data having an initial angular resolution, wherein the initial angular resolution corresponds to a first angular separation between each successive pulse emitted from the LIDAR device;

identify, based on the initial point cloud data, a reflective feature in the scanning zone;

locate at least one edge of the reflective feature; and

based on the located at least one edge of the reflective feature, determine;

(i) an enhancement region that corresponds to the reflective feature, and (ii) an enhanced angular resolution for a subsequent scan, wherein the enhanced angular resolution corresponds to a second angular separation between each successive pulse emitted from the LIDAR device, wherein the second angular separation is less than the first angular separation, and wherein the enhanced angular resolution is determined so as to provide a higher spatial resolution in at least a portion of subsequent point cloud data from the subsequent scan, wherein the portion corresponds to the determined enhancement region.

11. The autonomous vehicle system according to claim 10, wherein the controller is configured to, during the subsequent scan, scan the LIDAR device through a subsequent range of orientations corresponding to at least the enhancement region such that the portion of the subsequent point cloud data corresponding to the reflective feature has the higher spatial resolution.

12. The autonomous vehicle system according to claim 11, wherein the controller is configured to scan the LIDAR device during the subsequent scan in response to determining, based on the initial point cloud data, that the reflective feature is located at a distance exceeding a threshold distance.

13. The autonomous vehicle system according to claim 10, wherein identifying the reflective feature in the scanning zone is based on detecting a discontinuity in distances to the LIDAR device of points in the initial point cloud data that are angularly adjacent, with respect to the LIDAR device.

14. The autonomous vehicle system according to claim 10, wherein identifying the reflective feature further comprises identifying a reflective feature in motion based on the initial point cloud data.

15. The autonomous vehicle system according to claim 14, wherein the controller is further configured to predict a position of the reflective feature in motion, based on one or more previous point cloud data indicating previous positions of the reflective feature in motion, wherein a position of the enhancement region is determined based on the predicted position of the reflective feature in motion.

16. The autonomous vehicle system according to claim 10, wherein the controller is configured to cause the LIDAR device to scan the entire scanning zone during a scanning interval, wherein the subsequent scan is initiated during a subsequent scanning interval based on information indicative of the reflective feature received during the scanning interval.

17. The autonomous vehicle system of claim 11, wherein the controller is further configured to analyze the initial point cloud data and the subsequent point cloud data to identify one or more obstacles in the scanning zone interfering with a current path of the autonomous vehicle.

18. The autonomous vehicle system of claim 17, wherein the controller is further configured to determine a modified path of the autonomous vehicle that avoids the identified one or more obstacles, and wherein the controller is further configured to cause the autonomous vehicle to navigate along the modified path.

20. The autonomous vehicle system of claim 10, wherein the controller configured to identify, based on the initial point cloud data, a reflective feature in the scanning zone comprises the controller configured to define a bounding region encompassing the reflective feature, and wherein the enhancement region is defined near edges of the bounding region.