Method and System for Ladar Transmission with Spiral Dynamic Scan Patterns

• US 20160047898A1
• Filed: 08/14/2015
• Published: 02/18/2016
• Est. Priority Date: 08/15/2014
• Status: Active Grant

• Current Assignee: AEye, Inc.
• Original Assignee: US Ladar, Inc.
• Inventors: Dussan, Luis Carlos
• Granted Patent: US 10,088,558 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 17/87 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 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4861 Circuits for detection, sampling, integration or read-out
• CPC Class Codes: G01S 7/499 using polarisation effects

Abstract

Various embodiments are disclosed for improved scanning ladar transmission, including but not limited to an example embodiment where a scanning ladar transmission system employs a spiral dynamic scan pattern.

Claims

1. A method comprising:

processing a shot list, the shot list comprising a plurality of range points for targeting by a scanning ladar transmission system;

controlling a spiral dynamic scan pattern for the scanning ladar transmission system by scanning a mirror to a plurality of mirror scan positions based on the processed shot list to target the range points of the processed shot list according to the spiral dynamic scan pattern, wherein the mirror scan positions define where the scanning ladar transmission system is targeted; and

transmitting, by the controlled scanning ladar transmission system, a plurality of ladar pulses toward the range points of the processed shot list in accordance with the spiral dynamic scan pattern.

2. The method of claim 1 wherein the spiral dynamic scan pattern comprises an elliptical spiral dynamic scan pattern.

3. The method of claim 2 wherein the elliptical spiral dynamic scan pattern includes a member of the group consisting of interellipse skipping and interellipse detouring.

4. The method of claim 1 wherein the mirror comprises a first mirror and a second mirror, the first mirror scanning with respect to a first axis for targeting the scanning ladar transmission system along the first axis, the second mirror scanning with respect to a second axis that is orthogonal to the first axis for targeting the scanning ladar transmission system along the second axis, wherein the combination of the mirror scan positions for the first and second mirrors defines the range points to which the scanning ladar transmission system is targeted;

and

wherein the controlling step comprises;

scanning the first mirror in a plurality of directions in a resonant mode based on the processed shot list; and

scanning the second mirror in a plurality of directions in a resonant mode based on the processed shot list.

5. The method of claim 4 further comprising:

controlling the scanning steps by applying a first driving voltage to the first mirror and applying a second driving voltage to the second mirror, each driving voltage having an amplitude.

6. The method of claim 5 further comprising:

controlling an amplitude of the spiral for the spiral dynamic scan pattern by varying the amplitudes of the first and second driving voltages.

7. The method of claim 6 wherein the spiral dynamic scan pattern comprises an elliptical spiral dynamic scan pattern, the method further comprising:

varying the amplitudes of the first and second driving voltages to perform an interellipse skip for the elliptical spiral dynamic scan pattern.

8. The method of claim 6 wherein the spiral dynamic scan pattern comprises an elliptical spiral dynamic scan pattern, the method further comprising:

varying the amplitudes of the first and second driving voltages to perform an interellipse detour for the elliptical spiral dynamic scan pattern.

9. The method of claim 6 wherein the spiral dynamic scan pattern comprises an elliptical spiral dynamic scan pattern, the method further comprising:

varying the amplitudes of the first and second driving voltages to perform an ellipse skip for the elliptical spiral dynamic scan pattern.

10. The method of claim 6 wherein the spiral dynamic scan pattern comprises an elliptical spiral dynamic scan pattern, the method further comprising:

varying the amplitudes of the first and second driving voltages to perform an ellipse repeat for the elliptical spiral dynamic scan pattern.

11. The method of claim 4 wherein the first and second mirrors comprise microelectromechanical systems (MEMS) mirrors.

12. The method of claim 4 further comprising:

a light source directing a plurality of ladar pulses onto the first mirror;

the first mirror reflecting the ladar pulses onto the second mirror; and

the second mirror reflecting the ladar pulses for transmission toward the targeted range points, the targeted range points being defined by the combination of mirror scan positions for the first and second mirrors when the ladar pulses are incident thereon.

13. The method of claim 12 wherein the step of the first mirror reflecting the ladar pulses onto the second mirror comprises the first mirror reflecting the ladar pulses through relay imaging optics onto the second mirror.

14. The method of claim 1 further comprising;

generating the shot list to define the spiral dynamic scan pattern.

15. The method of claim 14 wherein the spiral dynamic scan pattern comprises an elliptical spiral dynamic scan pattern, and wherein the generating step comprises;

a processor sorting a plurality of the range points into a sort order to create the shot list, wherein the sorting comprises the processor identifying a plurality of interellipse skips within the elliptical spiral dynamic scan pattern based on a parameter indicative of an amount of time needed by the scanning ladar transmission system to scan from a current ring of the spiral to another ring of the spiral.

16. The method of claim 14 wherein the generating step comprises;

a processor sorting a plurality of the range points into a sort order to create the shot list, wherein the sorting comprises the processor identifying a plurality of ellipse repeats within the elliptical spiral dynamic scan pattern based on a parameter indicative of an amount of time needed between successive ladar pulses.

17. The method of claim 14 wherein the generating step comprises;

a processor sorting a plurality of the range points into a sort order to create the shot list, wherein the sorting comprises the processor identifying a plurality of interellipse detours within the elliptical spiral dynamic scan pattern based on a parameter indicative of an amount of time needed by the scanning ladar transmission system to (i) scan from a current ring of the spiral to another ring of the spiral, (ii) scan to a range point in the another ring, and (iii) return to the current ring.

18. A method comprising:

translating by a processor a range point list for ladar scanner targeting into a shot list for ladar scanner targeting in a manner whereby the shot list supports a spiral dynamic scan pattern, wherein the range point list comprises a plurality of range points, and wherein the shot list comprises a plurality of ordered range points from the range point list.

19. An apparatus comprising:

a scanning ladar transmission system configured to direct a plurality of ladar pulses toward a plurality of range points via a plurality of scanable mirrors, wherein the scanning ladar transmission system comprises;

a beam scanner, the beam scanner including a first mirror and a second mirror, wherein the beam scanner is configured to (1) scan the first mirror to a plurality of mirror scan positions in response to a first driving voltage to target the scanning ladar transmission system along a first axis, and (2) scan the second mirror to a plurality of mirror scan positions in response to a second driving voltage to target the scanning ladar transmission system along a second axis, and wherein the combination of the mirror scan positions for the first and second mirrors defines the range points to which the scanning ladar transmission system is targeted; and

a beam scanner controller, wherein the beam scanner controller is configured to generate the first and second driving voltages for use by the beam scanner such that the first and second driving voltages define a spiral dynamic scan pattern for the scanning ladar transmission system with respect to the range points.

20. The apparatus of claim 19 wherein the spiral dynamic scan pattern comprises an elliptical spiral dynamic scan pattern.

21. The apparatus of claim 19 wherein the scanning ladar transmission system further comprises:

a light source positioned and configured to direct a plurality of ladar pulses onto the first mirror, whereupon the first mirror is configured to reflect the ladar pulses onto the second mirror, whereupon the second mirror is configured to reflect the ladar pulses for transmission toward the targeted range points, the targeted range points being defined by the combination of mirror scan positions for the first mirror and the second mirror when the ladar pulses are incident thereon.

22. The apparatus of claim 21 wherein the first and second mirrors comprise a microelectromechanical systems (MEMS) mirrors.

23. The apparatus of claim 21 wherein the beam scanner is further configured to (1) scan the first mirror in plurality of directions in a resonant mode in response to the first driving voltage, and (2) scan the second mirror in a plurality of directions in a resonant mode in response to the second driving voltage.

24. The apparatus of claim 23 wherein the spiral dynamic scan pattern comprises an elliptical spiral dynamic scan pattern, and wherein the beam scanner controller is configured to vary an amplitude of the first driving voltage and an amplitude of the second driving voltage to control an amplitude of the spiral for the elliptical spiral dynamic scan pattern.

25. The apparatus of claim 24 wherein the beam scanner controller is further configured to vary the amplitudes of the first and second driving voltages to cause the beam scanner to scan the first the second mirrors in a fashion that defines an interellipse skip for the elliptical spiral dynamic scan pattern.

26. The apparatus of claim 25 wherein the beam scanner controller is further configured to generate the first and second driving voltages based on a shot list that defines a targeting order for the range points, the apparatus further comprising:

a processor configured to identify a plurality of interellipse skips within the elliptical spiral dynamic scan pattern for the shot list based on a parameter indicative of an amount of time needed by the scanning ladar transmission system to scan from a current ring of the spiral to another ring of the spiral.

27. The apparatus of claim 26 wherein the processor is part of the beam scanner controller.

28. The apparatus of claim 24 wherein the beam scanner controller is further configured to vary the amplitudes of the first and second driving voltages to cause the beam scanner to scan the first the second mirrors in a fashion that defines an interellipse detour for the elliptical spiral dynamic scan pattern.

29. The apparatus of claim 28 wherein the beam scanner controller is further configured to generate the first and second driving voltages based on a shot list that defines a targeting order for the range points, the apparatus further comprising:

a processor configured to identify a plurality of interellipse detours within the elliptical spiral dynamic scan pattern for the shot list based on a parameter indicative of an amount of time needed by the scanning ladar transmission system to (i) scan from a current ring of the spiral to another ring of the spiral, (ii) scan to a range point in the another ring, and (iii) return to the current ring.

30. The apparatus of claim 29 wherein the processor is part of the beam scanner controller.

31. The apparatus of claim 24 wherein the beam scanner controller is further configured to vary the amplitudes of the first and second driving voltages to cause the beam scanner to scan the first the second mirrors in a fashion that defines an ellipse repeat for the elliptical spiral dynamic scan pattern.

32. The apparatus of claim 31 wherein the beam scanner controller is further configured to generate the first and second driving voltages based on a shot list that defines a targeting order for the range points, the apparatus further comprising:

a processor configured to identify a plurality of ellipse repeats within the elliptical spiral dynamic scan pattern for the shot list based on a parameter indicative of an amount of time needed between successive ladar pulses.

33. The apparatus of claim 32 wherein the processor is part of the beam scanner controller.

34. The apparatus of claim 24 wherein the beam scanner controller is further configured to vary the amplitudes of the first and second driving voltages to cause the beam scanner to scan the first the second mirrors in a fashion that defines an ellipse skip for the elliptical spiral dynamic scan pattern.

35. The apparatus of claim 21 wherein the beam scanner further comprises relay imaging optics between the first and second mirrors.