Retroreflector detection and avoidance in a LIDAR device

Patent metadata

Field	Value
Publication number	US-12025702-B2
Application number	US-202017028847-A
Country	US
Kind code	B2
Filing date	Sep 22, 2020
Priority date	Nov 29, 2019
Publication date	Jul 2, 2024
Grant date	Jul 2, 2024

Abstract

A light detection and ranging (LIDAR) device includes a light emitter configured to emit light pulses into a field of view and a detector configured to detect light in the field of view. The light emitter emits a first light pulse. The detector detects, during a first measurement period, at least one reflected light pulse that is indicative of reflection by a retroreflector based on a shape of a reflected light pulse, a magnitude of a reflected light pulse, and/or a time separation between two reflected light pulses. In response to detecting the at least one reflected light pulse indicative of reflection by a retroreflector, the light emitter is deactivated for one or more subsequent measurement periods. Additionally, the LIDAR device may inform one or more other LIDAR devices by transmitting to a computing device information indicative of the retroreflector being within the field of view of the light emitter.

First claim

What is claimed is:

1. A method, comprising:
emitting, by a light emitter of a light detection and ranging (LIDAR) device, a first light pulse into a field of view of the light emitter;
determining that a detector of the LIDAR device detects, during a first measurement period, at least one reflected light pulse indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter;
in response to detecting the at least one reflected light pulse indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter, deactivating the light emitter during one or more subsequent measurement periods, wherein the one or more subsequent measurement periods occur after the first measurement period; and
determining when to reactivate the light emitter, wherein determining when to reactivate the light emitter comprises:
determining whether the detector detects, during the one or more subsequent measurement periods, one or more additional reflected light pulses indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter.

2. The method of claim 1 , wherein deactivating the light emitter during the one or more subsequent measurement periods comprises:
controlling the light emitter such that the light emitter does not emit light during the one or more subsequent measurement periods.

3. The method of claim 1 , wherein deactivating the light emitter during the one or more subsequent measurement periods comprises:
controlling the light emitter such that the light emitter emits light at a reduced level during the one or more measurement periods.

4. The method of claim 1 , further comprising:
transmitting, from the LIDAR device to a computing device, information indicative of the retroreflector or other highly reflective object being within the field of view of the light emitter and detected during the first measurement period.

5. The method of claim 1 , wherein determining when to reactivate the light emitter further comprises:
making a determination that the detector detects, during a second measurement period, an additional reflected light pulse indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter, wherein the second measurement period occurs after the first measurement period; and
in response to the determination, deactivating the light emitter during a third measurement period, wherein the third measurement period occurs after the second measurement period.

6. The method of claim 5 , wherein the LIDAR device includes one or more additional light emitters, wherein the additional reflected light pulse indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter comprises stray light from the one or more additional light emitters that is reflected by the retroreflector or other highly reflective object within the field of view of the light emitter.

7. The method of claim 5 , further comprising:
emitting a secondary light pulse having a lower intensity than the first light pulse, wherein the additional reflected light pulse indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter comprises light from the secondary light pulse that is reflected by the retroreflector or other highly reflective object within the field of view of the light emitter.

8. The method of claim 1 , wherein determining when to reactivate the light emitter further comprises:
making a determination that the detector does not detect, during a second measurement period, an additional reflected light pulse indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter, wherein the second measurement period occurs after the first measurement period; and
in response to the determination, reactivating the light emitter such that the light emitter emits, during a third measurement period, a second light pulse into the field of view of the light emitter, wherein the third measurement period occurs after the second measurement period.

9. The method of claim 1 , wherein the light emitter emits the first light pulse during the first measurement period, wherein determining that the detector detects, during the first measurement period, at least one reflected light pulse indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter comprises:
detecting, by the detector, a reflected light pulse during the first measurement period; and
determining that the reflected light pulse is indicative of reflection by a retroreflector or other highly reflective object based on at least a shape of the reflected light pulse.

10. The method of claim 1 , wherein the light emitter emits the first light pulse during a preceding measurement period, wherein the preceding measurement period occurs before the first measurement period, wherein the light emitter is a primary light emitter of the LIDAR device, wherein the LIDAR device includes a secondary light emitter, wherein the primary light emitter does not emit light during the first measurement period, further comprising emitting, by the secondary light emitter, a secondary light pulse during the first measurement period, wherein the secondary light pulse has a lower intensity than the first light pulse, wherein determining that the detector detects, during the first measurement period, at least one reflected light pulse indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter comprises:
detecting, by the detector, a reflected light pulse during the first measurement period; and
determining that the reflected light pulse is indicative of reflection by a retroreflector or other highly reflective object based on at least the reflected light pulse having a magnitude that exceeds a predetermined threshold.

11. The method of claim 1 , wherein the light emitter is a primary light emitter of the LIDAR device, wherein the LIDAR device includes a secondary light emitter, and wherein the primary light emitter emits the first light pulse during the first measurement period, further comprising emitting, by the secondary light emitter, a secondary light pulse during the first measurement period, wherein the secondary light pulse has a lower intensity than the first light pulse, wherein the first light pulse and the secondary light pulse are separated in time by a predetermined time difference, wherein determining that the detector detects, during the first measurement period, at least one reflected light pulse indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter comprises:
detecting, by the detector, a first reflected light pulse at a first time during the first measurement period and a second reflected light pulse at a second time during the first measurement period; and
determining that the first and second reflected light pulses are indicative of reflection by a retroreflector or other highly reflective object within the field of view of the light emitter based on at least a time difference between the first time and the second time corresponding to the predetermined time difference.

12. A light detection and ranging (LIDAR) device, comprising:
a light emitter configured to emit light pulses into a field of view of the light emitter;
a detector configured to detect li

Assignees

• Waymo Llc

Inventors

• Droz Pierre-Yves
• Marx Michael
• Stark Ethan

Classifications

• G01S7/4815

  using multiple transmitters · CPC title

• G01S17/89

  for mapping or imaging · CPC title

• G01S7/484

  Transmitters · CPC title

• G01S7/4817

  relating to scanning · CPC title

• G01S17/931

  of land vehicles · CPC title