Laser radar device and object detection method

Patent metadata

Field	Value
Publication number	US-9689985-B2
Application number	US-201414577776-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Dec 27, 2013
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A laser radar device includes: a projection part repeatedly performing processing of projecting measurement light that is of a pulsed laser beam to a predetermined monitoring area in a measurement period having a predetermined first length, the processing being repeated in c cycles (c≧2) in a detection period having a predetermined second length; a light receiver including n1 (n1≧2) light receiving elements and receiving reflected light of the measurement light in directions different from one another; a selector selecting light receiving signals of the n1 light receiving elements in each measurement period and output n2 (n2≧2) light receiving signals; a sampling part sampling the light receiving signals output from the selector s (s≧2) times every time the measurement light is projected; and a detector performing processing of detecting an object in a detection-period-based period based on sampling values.

First claim

The invention claimed is:

1. A laser radar device provided in a vehicle, comprising:
a projection part configured to repeatedly perform processing of projecting measurement light that is of a pulsed laser beam to a predetermined monitoring area in a measurement period having a predetermined first length, the processing being repeated in c cycles (c≧2) in a detection period having a predetermined second length;
a light receiver that comprises n1 (n1≧2) light receiving elements and is configured to receive reflected light of the measurement light in directions different from one another;
a selector configured to select light receiving signals of the n1 light receiving elements in each measurement period and output n2 (n2≧2) light receiving signals;
a sampling part configured to sample the light receiving signals output from the selector s (s≧2) times every time the measurement light is projected; and
a detector configured to perform processing of detecting an object in a detection-period-based period based on sampling values obtained by the sampling,
wherein the selector alternately repeats first selection processing of uniformly selecting the light receiving signal of each of the light receiving elements and second selection processing in which a frequency of selecting the light receiving signal of the light receiving element receiving reflected light from a traveling direction of the vehicle is increased when the detector does not detect the object, and the selector repeats the first selection processing when the detector detects the object.

2. The laser radar device according to claim 1 , wherein the selector selects the light receiving signals from the n1 light receiving elements, adds the plurality of selected light receiving signals, and outputs the added light receiving signal.

3. The laser radar device according to claim 1 , further comprising:
an integrator configured to integrate sampling values of the light receiving signals from the identical light receiving element, the sampling values being sampled at an identical sampling clock time in the detection period,
wherein the projection part projects the measurement light a plurality of times in the measurement period.

4. The laser radar device according to claim 3 , wherein the integrator integrates the sampling values throughout the plurality of detection periods.

5. The laser radar device according to claim 1 , wherein the selector makes a selection from the light receiving signals in each of n2 groups and outputs one light receiving signal in each group, the n1 light receiving elements being divided into the n2 groups.

6. The laser radar device according to claim 1 , wherein n1≦c×n2 holds.

7. The laser radar device according to claim 1 , wherein the sampling part comprises n2 A/D converters configured to concurrently sample the n2 light receiving signals output from the selector.

8. The laser radar device according to claim 1 ,
wherein the selector increases a frequency of selecting the light receiving signal of the light receiving element receiving reflected light from a traveling direction of the vehicle when the speed of the vehicle is greater than or equal to a predetermined threshold.

9. An object detection method provided in a vehicle, comprising:
a projection step of repeatedly performing processing of projecting measurement light that is of a pulsed laser beam to a predetermined monitoring area in a measurement period having a predetermined first length, the processing being repeated in c cycles (c≧2) in a detection period having a predetermined second length;
a light receiving step in which n1 (n1≧2) light receiving elements receive reflected light of the measurement light in directions different from one another;
a selection step of selecting light receiving signals of the n1 light receiving elements in each measurement period and outputting n2 (n2≧2) light receiving signals;
a sampling step of sampling the light receiving signals output from the selection steps s (s≧2) times every time the measurement light is projected; and
a detection step of performing processing of detecting an object in a detection-period-based period based on sampling values obtained by the sampling,
wherein the selection step alternately repeats first selection processing of uniformly selecting the light receiving signal of each of the light receiving elements and second selection processing in which of frequency of selecting the light receiving signal of the light receiving element receiving reflected light from a traveling direction of the vehicle is increased when the detection step does not detect the object, and the selection step repeats the first selection processing when the detection step detects the object.

Assignees

• Nishiguchi Tadao
• Itao Daisuke
• Hirota Satoshi
• Omron Automotive Electronics

Inventors

• Nishiguchi Tadao
• Itao Daisuke
• Hirota Satoshi

Classifications

• G01S7/4861

  Circuits for detection, sampling, integration or read-out · CPC title

• G01S17/931

  of land vehicles · CPC title

• G01S17/10

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

• G01S7/497

  Means for monitoring or calibrating · CPC title

• G01S17/04 Primary

  Systems determining the presence of a target · CPC title