LIDAR sensor window configuration for improved data integrity

• US 10,168,423 B2
• Filed: 01/27/2017
• Issued: 01/01/2019
• Est. Priority Date: 01/27/2017
• Status: Active Grant

• Current Assignee: Waymo LLC (Alphabet Inc.)
• Original Assignee: Waymo LLC (Alphabet Inc.)
• Inventors: Lombrozo, Peter Craig, Rivera, Felix Jose Alvarez
• Primary Examiner(s): Ismail, Mahmoud S
• Application Number:
  US15/417,654
• Publication Number:
  US 20180217242A1
• Time in Patent Office: 704 Days
• Field of Search: 701 28, 356409, 356246, 356 501, 25027725, 235454
• 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 2007/4977 including means to prevent or remove the obstruction
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G06T 7/00 Image analysis

Abstract

The disclosure relates to determining whether an optical interferent is located on a sensor window and providing a way to identify and discard erroneous sensor data. An example system includes a housing, having a first sensor window and a second sensor window, a laser light source, and an optical sensor. The first window has a first property for deflecting water, and the second window has a second property for deflecting water different from the first property. The source is configured to generate a beam of light through the first window. One or more processors are configured to receive sensor data from the optical sensor and determine that an optical interferent is located on a surface of at least one of the first window and the sensor window based on a comparison between sensor data corresponding to the first window and sensor data corresponding to the second window.

Claims

1. A system for determining whether an optical interferent is located on a sensor window, the system comprising:

a housing including a first sensor window and a second sensor window, the first sensor window having a first external surface property for deflecting water and the second sensor window having a second external surface property for deflecting water different from the first external surface property;

a laser configured to generate a beam of light through at least the first sensor window;

an optical sensor; and

one or more processors configured to;

receive sensor data corresponding to light from the beam of light detected by the optical sensor identifying distances from the optical sensor to an object in an external environment of the housing;

determine that an optical interferent is located on a surface of at least one of the first sensor window and the second sensor window based on a comparison between a portion of the sensor data from the first sensor window corresponding to the object and a portion of the sensor data from the second sensor window corresponding to the object; and

when the comparison indicates that the optical interferent is located on the surface of at least one of the first sensor window and the second sensor window, control the vehicle in an autonomous driving mode based on the comparison.

2. The system of claim 1, wherein the first external surface property corresponds to an external surface of the first sensor window being more hydrophobic than an external surface of the second sensor window.

3. The system of claim 1, wherein the first external surface property corresponds to an external surface of the first sensor window being more hydrophilic than an external surface of the second sensor window.

4. The system of claim 1, wherein the first external surface property corresponds to a first coating applied to the first sensor window.

5. The system of claim 4, wherein the second external surface property corresponds to a second coating applied to the second sensor window, wherein the first coating and the second coating have different properties for deflecting water.

6. The system of claim 5, wherein the first external surface property corresponds to a first material of the first sensor window.

7. The system of claim 6, wherein the second external surface property corresponds to a second material of the second sensor window, wherein the first material and the second material have different properties for deflecting water.

8. The system of claim 1, wherein the comparison includes a comparison of a first distance to an object determined from the portion of the sensor data from the first sensor window and a second distance to the object determined from the portion of the sensor data from the second sensor window.

9. The system of claim 8, wherein the first distance and the second distance correspond to different locations of an object detected within a predetermined period of time.

10. The system of claim 1, wherein the first sensor window and the second sensor window comprise different portions of a single window.

11. The system of claim 1, wherein the optical interferent is water.

12. The system of claim 1, further comprising a vehicle, and wherein the housing is attached to the vehicle.

13. The system of claim 1, wherein the one or more processors are further configured to, when the comparison indicates that the optical interferent is located on the first sensor window, temporarily ignore the sensor data from the first sensor window when controlling the vehicle in the autonomous driving mode.

14. The system of claim 1, wherein the one or more processors are further configured to, when the comparison indicates that the optical interferent is located on the second sensor window, temporarily ignore the sensor data from the second sensor window when controlling the vehicle in the autonomous driving mode.

15. The system of claim 1, wherein the housing is configured to rotate such that the laser is configured to generate a beam of light through both the first sensor window and the second sensor window at different times while the housing is rotating.

16. The system of claim 15, further comprising a mirror element configured to rotate and reflect the beam of light through both the first sensor window and the second sensor window at different times while the housing is rotating.

17. The system of claim 1, further comprising a second laser configured to generate a second beam of light through the second sensor window while the laser generates the beam of light through the first sensor window.

18. The system of claim 17, wherein the second laser is fixed relative to the second sensor window and the laser is fixed relative to the first sensor window.

19. The system of claim 18, wherein the housing is configured to rotate 360 degrees such that the laser and the second laser rotate with the housing.

20. The system of claim 1, wherein the laser is semiconductor waveguide laser, a fiber laser or an excimer laser.