Scan patterns for lidar systems

• US 9,869,754 B1
• Filed: 03/22/2017
• Issued: 01/16/2018
• Est. Priority Date: 03/22/2017
• Status: Active Grant

• Current Assignee: Luminar Technologies, Inc.
• Original Assignee: Luminar Technologies, Inc.
• Inventors: Campbell, Scott R., Cleye, Rodger W., Eichenholz, Jason M., Martin, Lane A., Weed, Matthew D.
• Primary Examiner(s): Abraham, Samantha K
• Application Number:
  US15/466,702
• Time in Patent Office: 300 Days
• 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 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4812 transmitted and received beams following a coaxial path
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: G01S 7/4817 relating to scanning
• 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: G01S 7/487 Extracting wanted echo signals , e.g. pulse detection

Abstract

In one embodiment, a system includes a first lidar sensor, which includes a first scanner configured to scan first pulses of light along a first scan pattern and a first receiver configured to detect scattered light from the first pulses of light. The system also includes a second lidar sensor, which includes a second scanner configured to scan second pulses of light along a second scan pattern and a second receiver configured to detect scattered light from the second pulses of light. The first scan pattern and the second scan pattern are at least partially overlapped. The system further includes an enclosure, where the first lidar sensor and the second lidar sensor are contained within the enclosure. The enclosure includes a window configured to transmit the first pulses of light and the second pulses of light.

Claims

1. A system comprising:

a first lidar sensor comprising;

a first scanner configured to scan a first set of pulses of light along a first scan pattern; and

a first receiver configured to detect scattered light from the first set of pulses of light;

a second lidar sensor comprising;

a second scanner configured to scan a different second set of pulses of light along a second scan pattern, wherein the first scan pattern and the second scan pattern are at least partially overlapped; and

a second receiver configured to detect scattered light from the second set of pulses of light; and

an enclosure, wherein;

the first lidar sensor and the second lidar sensor are contained within the enclosure; and

the enclosure comprises a window configured to transmit the first set of pulses of light and the second set of pulses of light.

2. The system of claim 1, wherein the first scan pattern and the second scan pattern are scanned out of synchronization with respect to one another.

3. The system of claim 2, wherein the first and second scan patterns being scanned out of synchronization with respect to one another is associated with:

the first receiver detecting substantial cross-talk light from the second pulses of light for less than approximately 0.1% of pixels in the first scan pattern; and

the second receiver detecting substantial cross-talk light from the first pulses of light for less than approximately 0.1% of pixels in the second scan pattern.

4. The system of claim 2, wherein:

the first scan pattern comprises a first-scan-pattern x-component and a first-scan-pattern y-component; and

the second scan pattern comprises a second-scan-pattern x-component and a second-scan-pattern y-component.

5. The system of claim 4, wherein the first and second scan patterns being scanned out of synchronization comprises the first-scan-pattern x-component having a particular phase shift relative to the second-scan-pattern x-component.

6. The system of claim 4, wherein the first and second scan patterns being scanned out of synchronization comprises the first-scan-pattern y-component having a particular phase shift relative to the second-scan-pattern y-component.

7. The system of claim 4, wherein the first and second scan patterns being scanned out of synchronization comprises the first-scan-pattern y-component being inverted with respect to the second-scan-pattern y-component.

8. The system of claim 1, further comprising a light source configured to emit pulses of light, wherein the emitted pulses of light are split into the first pulses of light and the second pulses of light, wherein the first pulses of light are supplied to the first scanner, and the second pulses of light are supplied to the second scanner.

9. The system of claim 1, wherein:

the first lidar sensor further comprises a first light source configured to emit the first pulses of light which are supplied to the first scanner; and

the second lidar sensor further comprises a second light source configured to emit the second pulses of light which are supplied to the second scanner.

10. The system of claim 1, wherein the first pulses of light and the second pulses of light are each incident on the window at nonzero angles of incidence.

11. The system of claim 1, wherein the window comprises an interior surface and an exterior surface, wherein the interior and exterior surfaces each comprise a dielectric coating that is anti-reflecting at a wavelength of the first pulses of light and a wavelength of the second pulses of light.

12. The system of claim 11, wherein the dielectric coating of the exterior surface is further high-reflecting at wavelengths away from the wavelengths of the first pulses of light and the second pulses of light.

13. The system of claim 1, wherein the window has an optical transmission of greater than or equal to 70% for a wavelength of the first pulses of light and a wavelength of the second pulses of light.

14. The system of claim 1, wherein the window comprises an exterior surface with a coating that is oleophobic, hydrophobic, or hydrophilic.

15. The system of claim 1, wherein the first scan pattern and the second scan pattern are overlapped in a crossing manner.

16. The system of claim 1, wherein the first scan pattern and the second scan pattern are overlapped in a non-crossing manner.

17. The system of claim 1, further comprising a third lidar sensor contained within the enclosure, wherein the third lidar sensor comprises:

a third scanner configured to scan third pulses of light along a third scan pattern, wherein the second scan pattern and the third scan pattern are at least partially overlapped; and

a third receiver configured to detect scattered light from the third pulses of light.

18. The system of claim 1, wherein the first scanner and the second scanner each comprise one or more mirrors, wherein each mirror is mechanically driven by one or more mechanical actuators, wherein each actuator comprises a galvanometer scanner, a resonant scanner, a microelectromechanical systems (MEMS) device, or a voice coil motor.

19. The system of claim 1, further comprising a processor configured to determine a distance from the system to a target based on a time of flight for one or more of the first or second pulses of light to travel from the system to the target and back.

20. The lidar system of claim 1, wherein:

the first pulses of light and the scattered light from the first pulses of light are substantially coaxial; and

the second pulses of light and the scattered light from the second pulses of light are substantially coaxial.

21. The lidar system of claim 20, wherein:

the first lidar sensor further comprises a first overlap mirror configured to overlap the first pulses of light and the scattered light from the first pulses of light so that they are substantially coaxial, wherein the first overlap mirror comprises;

a first hole which the first pulses of light pass through; and

a first reflecting surface that reflects at least a portion of the scattered light from the first pulses of light toward the first receiver; and

the second lidar sensor further comprises a second overlap mirror configured to overlap the second pulses of light and the scattered light from the second pulses of light so that they are substantially coaxial, wherein the second overlap mirror comprises;

a second hole which the second pulses of light pass through; and

a second reflecting surface that reflects at least a portion of the scattered light from the second pulses of light toward the second receiver.