LIDAR with enhanced utilization of a remotely located mirror

• US 10,151,836 B2
• Filed: 11/22/2017
• Issued: 12/11/2018
• Est. Priority Date: 08/10/2016
• Status: Active Grant

• Current Assignee: O'Keeffe, James Thomas
• Original Assignee: O'Keeffe, James Thomas
• Inventors: O'Keeffe, James Thomas
• Primary Examiner(s): Abraham, Samantha K
• Application Number:
  US15/820,438
• Publication Number:
  US 20180095175A1
• Time in Patent Office: 384 Days
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• 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 17/66 Tracking systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/4808 Evaluating distance, position or velocity data
• CPC Class Codes: G02B 5/08 Mirrors vehicle mirrors involving special optical features B60R1/08

Abstract

A LIDAR can utilize remote mirrors discovered in the local environment to gather reflections from remote locations. In one embodiment, a laser range finder identifies and tracks a remote mirror with variable placement in a field of view (e.g. a roadside mirror at an traffic intersection) and generates a dense non-uniform subset of outgoing laser pulses designed to cover the mirror portion of the field of view, thereby interrogating or data mining the indirect field of view offered by the remote mirror. In several embodiments a light detection and ranging (LIDAR) system, learns the position of a remotely located mirror, then identifies a subset of the laser reflections that have undergone deflection by that remote mirror and performs a correction step in the process of calculating 3D locations for the deflected subset of laser reflections.

Claims

1. A method comprising:

a. generating with a laser generator an outgoing laser pulse sequence;

b. detecting with a detector a set of laser reflections from at least one laser pulse in the outgoing laser pulse sequence;

wherein at least one of the set of laser reflections has undergone deflection by a remote mirror,

c. computing for each of the set of laser reflections a corresponding 3-dimensional (3D) location indicative of a corresponding reflection location, comprising the steps of;

determining whether the each of the set of laser reflection has undergone deflection by the remote mirror; and

performing at least one correction step in the process of computing the corresponding 3D location when the each of the set of laser reflections is determined to have undergone deflection by the remote mirror.

2. The method of claim 1 further comprising the step of computing a location of the remote mirror by processing sensor data;

and wherein the step of determining whether the each of the set of laser reflection has undergone deflection by the remote mirror is based at least in part on the computed location of the remote mirror.

3. The method of claim 1, further comprising the step of:

generating reflection data operable to indicate for each of the set of laser reflections a corresponding distance to the corresponding reflection location and a corresponding direction; and

wherein the step of computing for each of the set of laser reflections the corresponding 3D location indicative of the corresponding reflection location uses at least some of the reflection data.

4. The method of claim 3 wherein the step of determining whether the each of the set of laser reflections has undergone deflection by the remote mirror is performed by processing at least some of the reflection data.

5. The method of claim 1 further comprising the step of computing a location of the remote mirror based at least in part on data sensed from a local environment in a vicinity of the remote mirror;

and

wherein the step of determining whether the each of the set of laser reflections has undergone deflection by the remote mirror is based at least in part on the computed location of the remote mirror.

6. The method of claim 1 wherein the step of determining whether the each of the set of laser reflections has undergone deflection by the remote mirror is based on signals received from the remote mirror indicating an aspects of the remote mirror from a set of aspects consisting of (a classification for the remote mirror, a position of the remote mirror, an orientation of the remote mirror, a shape of the remote mirror, a curvature of the remote mirror and a transfer function indicating a relationship between incident and deflected angles for the remote mirror).

7. The method of claim 1 wherein the detector has a field of view;

and

wherein the remote mirror has a variable position in the field of view such that the remote mirror can occupy a variable portion of the field of view.

8. The method of claim 1 wherein the step of determining whether the each of the set of laser reflections has undergone deflection by the remote mirror is based at least in part on processing reflection data from at least one laser reflection in the set of laser reflections.

9. The method of claim 1 further comprising the step of tracking a location of the remote mirror;

and

wherein the step of determining whether the each of the set of laser reflection has undergone deflection by the remote mirror is based at least in part on the tracked location of the remote mirror.

10. The method of claim 1 further comprising the step of estimating a trajectory of the remote mirror relative to the detector;

and

wherein the step of determining whether the each of the set of laser reflection has undergone deflection by the remote mirror, is based at least in part on the estimated trajectory of the remote mirror.

11. A laser range finder comprising:

a. a laser generator that produces an outgoing laser pulse sequence;

b. a detector that detects a set of laser reflections from one or more laser pulses in the outgoing laser pulse sequence;

wherein upon detection, at least some of the laser reflections in the set of laser reflections have undergone deflection by a remote mirror, and

c. electronic circuitry, at least some of the electronic circuitry being coupled to the detector, wherein the electronic circuitry;

determines a deflected subset of the set of laser reflections that have undergone deflection by the remote mirror;

computes for each laser reflection in the set of laser reflections a corresponding 3-dimensional (3D) location indicative of a corresponding reflection location; and

performs for the each laser reflection in the deflected subset of laser reflections a correction step when computing the corresponding 3D location.

12. The laser range finder of claim 11 wherein the electronic circuitry is configured to correct with the correction step for the deflection of the deflected subset of the set of laser reflections by the remote mirror.

13. The laser range finder of claim 11 wherein the electronic circuitry determines a first portion of a field of view of the detector that contains at least some of the remote mirror and determines the deflected subset of the set of laser reflections that have undergone deflection by the remote mirror, based at least in part on the first portion of the field of view of the detector.

14. The laser range finder of claim 11 wherein the correction step functions to correct at least in part for the deflection by the remote mirror of a laser reflection from the set of laser reflections, in the computing of the corresponding 3D location.

15. The laser range finder of claim 11 wherein the detector has a field of view;

wherein the remote mirror has transient placement in the field of view of the detector; and

wherein at least some of the electronic circuitry functions to detect when the remote mirror is present in the field of view of the detector.

16. The laser range finder of claim 11 wherein some of the set of laser reflections are exclusive from the deflected subset of laser reflections in the set of laser reflections.

17. The laser range finder of claim 11 wherein the detector has a field of view comprising a set of all directions in which the detector can directly detect laser reflections;

and

wherein the correction step functions to provide a 3D location for at least one laser reflection from the deflected subset of laser reflections that is outside of the field of view, thereby utilizing the remote mirror to provide a 3D location from an indirect field of view.

18. The laser range finder of claim 11 wherein the laser generator scans a field of view comprising a set of all locations that can be directly illuminated by a laser pulse from the laser generator;

and

wherein at least one of the laser pulses in the outgoing laser pulse sequence is deflected by the remote mirror and thereby illuminates a corresponding reflection location exclusive form the set of all locations that can be directly illuminated by a laser pulse in the field of view.

19. The laser range finder of claim 11 further comprising a communication link between the laser range finder and the remote mirror to transmit one or more commands to the remote mirror and thereby cause the remote mirror to change a position or orientation of the remote mirror.

20. The laser range finder of claim 11 wherein the laser range finder is unattached to the remote mirror and can move independently of the remote mirror.

21. The laser range finder of claim 11, wherein for each of the set of laser reflections the corresponding 3D location has a corresponding accuracy for indicating the corresponding reflection location;

and wherein for each laser reflection in the set deflected subset of laser reflections the correction step functions to improve the accuracy of the corresponding 3D location for indicating the corresponding reflection location.

22. The laser range finder of claim 11 wherein the remote mirror has a position that is initially unknown to the laser range finder upon generation of a first laser pulse in the outgoing laser pulse sequence.

23. The laser range finder of claim 11 wherein the correction step is based at least in part on a previous 3D location calculated from a previous laser reflection detected by the detector.

24. A method comprising:

a. generating with a laser generator an outgoing laser pulse sequence;

b. detecting with a detector a set of laser reflections from one or more laser pulses in the outgoing laser pulse sequence and thereby generating reflection data indicative for each laser reflection in the set of laser reflections of a corresponding reflection location,

wherein upon detection by the detector, some of the laser reflections in the set of laser reflections have undergone deflection by a remote mirror;

c. determining a deflected subset of the set of laser reflections that have undergone deflection by the remote mirror; and

d. processing, for each laser reflection in the set of laser reflections, at least some of the reflection data to thereby generate a corresponding 3-dimensional (3D) location indicative of the corresponding reflection location; and

wherein the processing of the at least some of the reflection data to generate the corresponding 3D location includes a correction step performed exclusively when the each laser reflection in the set of laser reflections is in the deflected subset of the set of laser reflections.

25. The method of claim 24 further comprises the step of generating for each laser reflection in the set of laser reflections a corresponding initial 3D location and wherein for each laser reflection in the deflected subset of the set of laser reflections the correction step modifies the corresponding initial 3D locations to account at least in part for deflection by the remote mirror in the process of generating the corresponding 3D location.

26. The method of claim 24 wherein the deflected subset of the set of laser reflections is determined based on sensor data from an environment local to the detector, and wherein the sensor data is received by electronic circuitry coupled to the detector.

27. The method of claim 24 wherein the deflected subset of the set of laser reflections is determined based at least in part on a change of position of the remote mirror.

28. The method of claim 24 wherein for each laser reflection in the deflected subset of the set of laser reflections the correction step functions at least in part to correct the corresponding 3D location for deflection caused by the remote mirror.

29. The method of claim 24 wherein the detector has a field of view;

wherein the remote mirror has transient placement in the field of view; and

wherein the step of determining the deflected subset of the set of laser reflections that have undergone deflection by the remote mirror, is performed at least in part in response to detecting a presence of the remote mirror in the field of view.

30. The method of claim 24 further comprising the step of calculating a transfer function for the remote mirror and wherein the correction step, performed exclusively when the each laser reflection in the set of laser reflections is in the deflected subset of the set of laser reflections, is based at least in part on the transfer function for the remote mirror.