Method for dynamically controlling laser power

• US 10,114,111 B2
• Filed: 11/28/2017
• Issued: 10/30/2018
• Est. Priority Date: 03/28/2017
• Status: Active Grant

• Current Assignee: Luminar Technologies, Inc.
• Original Assignee: Luminar Technologies, Inc.
• Inventors: Russell, Austin K., Eichenholz, Jason M., Lingvay, Laurance S.
• Primary Examiner(s): Bolda, Eric L
• Application Number:
  US15/824,416
• Publication Number:
  US 20180284244A1
• Time in Patent Office: 336 Days
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 2007/4975 of sensor obstruction by, e.g. dirt- or ice-coating, e.g. by reflection measurement on front-screen
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 7/4804 Auxiliary means for detecting or identifying lidar signals or the like, e.g. laser illuminators
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4868 Controlling received signal intensity or exposure of sensor
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

To dynamically control power in a lidar system, a controller identifies a triggering event and provides a control signal to a light source in the lidar system adjusting the power of light pulses provided by the light pulse. Triggering events may include exceeding a threshold speed, being within a threshold distance of a person or other object, an atmospheric condition, etc. In some scenarios, the power is adjusted to address eye-safety concerns.

Claims

1. A method for dynamically varying an amount of laser power in a lidar system, the method comprising:

emitting light pulses by a light source in a lidar system;

identifying, by a controller in the lidar system, a triggering event for adjusting an amount of power for subsequent light pulses provided by the light source, the triggering event including detecting an atmospheric condition; and

providing, by the controller, a control signal to the light source adjusting the amount of power for the subsequent light pulses provided by the light source based on the triggering event.

2. The method of claim 1, wherein identifying the triggering event further includes detecting that a speed of a vehicle that includes the lidar system exceeds a threshold speed.

3. The method of claim 2, wherein adjusting the amount of power for the subsequent light pulses provided by the light source includes increasing the amount of power for the subsequent light pulses provided by the light source in response to identifying that the vehicle exceeds the threshold speed.

4. The method of claim 1, wherein:

the triggering event further includes a speed of a vehicle that includes the lidar system; and

adjusting the amount of power for the subsequent light pulses provided by the light source includes dynamically changing the amount of power based at least in part on the speed of the vehicle.

5. The method of claim 1, wherein identifying the triggering event further includes identifying an object within a threshold distance of the lidar system.

6. The method of claim 5, wherein adjusting the amount of power for the subsequent light pulses provided by the light source includes decreasing the amount of power for the subsequent light pulses provided by the light source in response to identifying the object within the threshold distance of the lidar system.

7. The method of claim 1, wherein adjusting the amount of power for the subsequent light pulses provided by the light source includes increasing the amount of power for the subsequent light pulses provided by the light source in response to detecting the atmospheric condition.

8. The method of claim 1, wherein identifying the triggering event further includes measuring an amount of ambient light present in the lidar system and determining that the amount of ambient light is less than a threshold light level.

9. The method of claim 8, wherein adjusting the amount of power for the subsequent light pulses provided by the light source includes decreasing the amount of power for the subsequent light pulses provided by the light source in response to determining that the amount of ambient light is less than the threshold light level.

10. The method of claim 1, wherein the amount of power for the subsequent light pulses is adjusted in one or more predetermined increments and further comprising:

upon adjusting the amount of power by a first predetermined increment, detecting light from some of the subsequent light pulses scattered by one or more remote targets to identify characteristics of return light pulses; and

adjusting the amount of power by a second predetermined increment based on the characteristics of the return light pulses.

11. The method of claim 1, wherein identifying the triggering event includes identifying a plurality of triggering events, wherein at least one of the plurality of triggering events is associated with increasing the amount of power and at least one other of the plurality of triggering events is associated with decreasing the amount of power;

determining a priority level for each of the plurality of triggering events; and

providing, by the controller, a control signal to the light source adjusting the amount of power for the subsequent light pulses provided by the light source based on the triggering event having a highest priority level.

12. A lidar system comprising:

a light source configured to emit light pulses;

a scanner configured to scan a field of view of the light source across a field of regard of the lidar system including direct the light pulses toward different points within the field of regard and at different angles relative to a forward-facing direction of a vehicle that includes the lidar system;

a detector configured to detect return light pulses from some of the light pulses scattered by one or more remote targets; and

a controller configured to adjust an amount of power for subsequent light pulses emitted by the light source, including;

identify a triggering event including measure an amount of ambient light present in the lidar system and determine that the amount of ambient light is less than a threshold light level; and

cause the light source to emit subsequent light pulses having an adjusted amount of power based on the triggering event

measuring an amount of ambient light present in the lidar system and determining that the amount of ambient light is less than a threshold light level.

13. The lidar system of claim 12, wherein to identify the triggering event, the controller is further configured to detect that a speed of the vehicle that includes the lidar system exceeds a threshold speed.

14. The lidar system of claim 13, wherein to adjust the amount of power for the subsequent light pulses emitted by the light source, the controller is configured to increase the amount of power for the subsequent light pulses emitted by the light source in response to identifying that the vehicle exceeds the threshold speed.

15. The lidar system of claim 12, wherein:

the triggering event further includes a speed of the vehicle that includes the lidar system; and

the amount of power of the subsequent light pulses is dynamically adjusted based at least in part on the speed of the vehicle.

16. The lidar system of claim 12, wherein to identify the triggering event, the controller is further configured to identify an object within a threshold distance of the lidar system.

17. The lidar system of claim 16, wherein to adjust the amount of power for the subsequent light pulses emitted by the light source, the controller is configured to decrease the amount of power for the subsequent light pulses emitted by the light source in response to identifying the object within the threshold distance of the lidar system.

18. The lidar system of claim 12, wherein to identify the triggering event, the controller is further configured to detect an atmospheric condition.

19. The lidar system of claim 18, wherein to adjust the amount of power for the subsequent light pulses emitted by the light source, the controller is configured to increase the amount of power for the subsequent light pulses emitted by the light source in response to detecting the atmospheric condition.

20. The lidar system of claim 12, wherein to adjust the amount of power for the subsequent light pulses emitted by the light source, the controller is configured to decrease the amount of power for the subsequent light pulses emitted by the light source in response to determining that the amount of ambient light is less than the threshold light level.

21. A controller in a lidar system comprising:

one or more processors; and

a non-transitory computer-readable memory coupled to the one or more processors and storing instructions thereon that, when executed by the one or more processors, cause the controller to;

provide a control signal to a light source to emit light pulses having an amount of power;

identify a triggering event including a vehicle or atmospheric condition; and

in response to identifying the triggering event, provide a control signal to the light source to emit subsequent light pulses having an adjusted amount of power based on the triggering event for a threshold time period and upon expiration of the threshold time period, the light source emits light pulses having the default amount of power.

22. The controller of claim 21,

wherein to identify the triggering event, the instructions cause the controller to detect that a speed of a vehicle that includes the lidar system exceeds a threshold speed;

and

to adjust the amount of power for the subsequent light pulses emitted by the light source, the instructions cause the controller to increase the amount of power for the subsequent light pulses emitted by the light source in response to identifying that the vehicle exceeds the threshold speed.

23. The controller of claim 21, wherein:

the triggering event includes a speed of a vehicle that includes the lidar system; and

the amount of power of the subsequent light pulses is dynamically adjusted based at least in part on the speed of the vehicle.

24. A method for dynamically varying an amount of laser power in a lidar system, the method comprising:

emitting light pulses by a light source in a lidar system;

identifying, by a controller in the lidar system, a triggering event for adjusting an amount of power for subsequent light pulses provided by the light source, the triggering event including a vehicle or atmospheric condition;

providing, by the controller, a control signal to the light source adjusting the amount of power for the subsequent light pulses provided by the light source based on the triggering event in one or more predetermined increments upon identifying an object within a first threshold distance of the lidar system;

upon adjusting the amount of power by a first predetermined increment, identifying the object within a second threshold distance of the lidar system, wherein the second threshold distance is shorter than the first threshold distance; and

adjusting the amount of power by a second predetermined increment in response to identifying the object within the second threshold distance of the lidar system.

25. A method for dynamically varying an amount of laser power in a lidar system, the method comprising:

emitting light pulses by a light source in a lidar system;

identifying, by a controller in the lidar system, a triggering event for adjusting an amount of power for subsequent light pulses provided by the light source, the triggering event including one or more signals from one or more autonomous vehicles each operating a lidar system; and

providing, by the controller, a control signal to the light source decreasing the amount of power for the subsequent light pulses provided by the light source in response to an indication from at least one of the one or more autonomous vehicle to decrease the amount of power.