Hyper temporal lidar with elevation-prioritized shot scheduling

Patent metadata

Field	Value
Publication number	US-11675059-B2
Application number	US-202117482983-A
Country	US
Kind code	B2
Filing date	Sep 23, 2021
Priority date	Mar 26, 2021
Publication date	Jun 13, 2023
Grant date	Jun 13, 2023

Abstract

A lidar system that includes a laser source can be controlled to schedule the firing of laser pulse shots at range points in a field of view. As part of this scheduling, the system can prioritize which elevations will be targeted with shots before other elevations based on defined criteria. Examples of such criteria can include prioritizing elevations corresponding to a horizon, prioritizing elevations which contain objects of interest (e.g., nearby objects, fast moving objects, objects heading toward the lidar system, etc).

First claim

What is claimed is:

1. A lidar apparatus comprising:
a laser source;
a mirror subsystem that defines where the lidar apparatus is aimed within a field of view, wherein the mirror subsystem is optically downstream from the laser source; and
a control circuit that orders a list of range points into a shot list of laser pulse shots that are to be fired by the laser source at the range points, each range point having a corresponding azimuth and elevation so that the range points on the range point list encompass a plurality of different azimuths and a plurality of different elevations;
wherein the control circuit orders the range point list into the shot list by (1) selecting which of the elevations are to be prioritized within the shot list over others of the elevations based on defined criteria and (2) ordering the range points into the shot list based on the selected elevation prioritizations so that the shot list defines an order for the laser pulse shots where laser pulse shots which target range points from the range point list at the selected prioritized elevations are to be fired before laser pulse shots which target range points from the range point list at the other elevations; and
wherein the defined criteria comprise (1) which of the elevations corresponds to a horizon in the field of view, (2) range information applicable to one or more detected objects in the field of view, (3) velocity information applicable to one or more detected objects in the field of view, (4) directional heading information applicable to one or more detected objects in the field of view, and/or (5) eye safety criteria.

2. The apparatus of claim 1 wherein the defined criteria comprises which of the elevations corresponds to a horizon in the field of view.

3. The apparatus of claim 2 wherein the horizon comprises a road horizon and wherein the control circuit prioritizes a selection of elevations that correspond to the road horizon.

4. The apparatus of claim 1 wherein the defined criteria comprises range information applicable to one or more detected objects in the field of view.

5. The apparatus of claim 4 wherein the control circuit prioritizes a selection of elevations which encompass one or more detected objects having a corresponding range beyond a defined range threshold.

6. The apparatus of claim 4 wherein the control circuit prioritizes a selection of elevations which encompass one or more detected objects having a corresponding range closer than a defined range threshold.

7. The apparatus of claim 4 wherein the range information comprises relative ranges for a plurality of the detected objects.

8. The apparatus of claim 1 wherein the defined criteria comprises velocity information applicable to one or more detected objects in the field of view.

9. The apparatus of claim 8 wherein the control circuit prioritizes a selection of elevations which encompass one or more detected objects having a corresponding velocity faster than a defined velocity threshold.

10. The apparatus of claim 8 wherein the velocity information comprises relative velocities for a plurality of the detected objects.

11. The apparatus of claim 1 wherein the defined criteria comprises directional heading information applicable to one or more detected objects in the field of view.

12. The apparatus of claim 1 wherein the defined criteria comprises eye safety criteria.

13. The apparatus of claim 12 wherein the control circuit employs a defined skip interval between successive elevation selections.

14. The apparatus of claim 1 wherein the defined criteria further comprises camera safety criteria.

15. The apparatus of claim 14 wherein the control circuit employs a defined skip interval between successive elevation selections.

16. The apparatus of claim 1 wherein the mirror subsystem comprises (1) a first mirror that is scannable through a plurality of azimuth scan angles and (2) a second mirror that is scannable through a plurality of elevation scan angles, and wherein the control circuit drives the first and second mirrors to control where the lidar apparatus is aimed in the field of view.

17. The apparatus of claim 16 wherein the control circuit generates firing commands for the laser source to fire laser pulse shots toward the range points via the first and second mirrors in accordance with the shot list.

18. The apparatus of claim 16 wherein the control circuit (1) drives the first mirror to scan through the azimuth scan angles in a resonant mode and (2) drives the second mirror to scan through the elevation scan angles in a point-to-point mode that varies as a function of the elevations applicable to the elevation scan angles for the range points targeted by laser pulse shots from the shot list.

19. The apparatus of claim 18 wherein the control circuit (1) drives the first mirror as a fast axis mirror and (2) drives the second mirror as a slow axis mirror.

20. The apparatus of claim 18 wherein the control circuit orders the range points into the shot list so that a plurality of range points from the range point list that are targeting a common elevation scan angle are grouped together in a sequence within the shot list.

21. The apparatus of claim 20 wherein the control circuit orders the range points into the shot list by (1) sorting the range points from the range point list into groups corresponding to different common elevation scan angles among the range points so that different ones of the groups comprise range points from the range point list that target different common elevation scan angles, (2) scheduling laser pulse shots targeting the range points in each group based on (i) a laser energy model that models how much energy is available from the laser source for laser pulse shots over time as compared to a plurality of energy requirements for the laser pulse shots and (ii) a mirror motion model that models the azimuth scan angles for the first mirror over time, and (3) ordering the groups of scheduled laser pulse shots in the shot list according to the defined criteria.

22. The apparatus of claim 21 wherein the laser energy model quantitively predicts available laser energy amounts for laser pulse shots based on a history of prior laser pulse shots.

23. The apparatus of claim 18 wherein the control circuit drives the first mirror to scan through the azimuth scan angles at a frequency between 100 Hz and 20 kHz.

24. The apparatus of claim 18 wherein the control circuit drives the first mirror to scan through the azimuth scan angles at a frequency between 10 kHz and 15 kHz.

25. The apparatus of claim 18 wherein the control circuit drives the second mirror according to a step control signal that varies as a function of the elevations applicable to the elevation scan angles for the range points targeted by laser pulse shots from the shot list.

26. The apparatus of claim 16 wherein the control circuit comprises (1) a system controller and (2) a beam scanner controller;
wherein the system controller performs the ordering and prioritization operations; and
wherein the beam scanner controller (1) provides firing commands to the laser source in accordance with the shot list and (2) drives scanning of the first and second mirrors.

27. The apparatus of claim 1 wherein the ordering of range points into the shot list based on the selected elevation prioritizations includes the control circuit ordering the

Assignees

• Aeye Inc

Inventors

• Feru Philippe
• Dussan Luis
• Benscoter Joel
• Jung Il Woong
• Liang Alex
• Polishchuk Igor
• Steinhardt Allan

Classifications

• G01S7/4817

  relating to scanning · CPC title

• G01S17/89

  for mapping or imaging · CPC title

• G01S17/10

  using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) · CPC title

• G01S7/4814

  of transmitters alone · CPC title

• G01S17/42

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) · CPC title