Device for determining a distance from an object, and corresponding method

Patent metadata

Field	Value
Publication number	US-2018321363-A1
Application number	US-201815969070-A
Country	US
Kind code	A1
Filing date	May 2, 2018
Priority date	May 2, 2017
Publication date	Nov 8, 2018
Grant date	—

Abstract

The invention relates to a device for determining a distance from an object, including a transmission device for emitting several light pulses including a pulse duration, including a reception device for receiving signals and for generating detection signals, and including an evaluation device for evaluating the detection signals. The evaluation device determines, on the basis of a number of the light pulses emitted and on the basis of the detection signals, probability values of several time windows which each have a respective time period equaling the pulse duration which relate to probabilities for reception of a signal within one of the time windows, respectively. In addition, the evaluation device determines, in accordance with the time-of-flight method, a measure of the distance of the object on the basis of the probability values determined. In addition, the invention relates to a corresponding method.

First claim

1 . Device for determining a distance from an object,
comprising a transmission device for emitting several light pulses comprising definable pulse duration, comprising a reception device for receiving signals and for generating detection signals associated with detection times and/or detection time intervals, and comprising an evaluation device for evaluating the detection signals, the evaluation device determining, on the basis of a number of the light pulses emitted and on the basis of the detection signals, probability values of several time windows which each comprise a respective time period equaling the pulse duration and which relate to probabilities for reception of a signal within one of the time windows, respectively, and wherein the evaluation device determines a measure of the distance of the object on the basis of the probability values determined in accordance with the time-of-flight method.

2 . Device as claimed in claim 1 ,
wherein the evaluation device determines a measure of a background light, and wherein the evaluation device determines the measure of the distance of the object on the basis of the determined probability values of two among the several time windows and on the basis of the determined measure of the background light.

3 . Device as claimed in claim 2 ,
wherein the evaluation device determines the probability values of several time windows which are directly consecutive in terms of time.

4 . Device as claimed in claim 2 ,
wherein the evaluation device determines the probability values of three time windows and wherein the evaluation device determines the measure of the distance of the object on the basis of the determined probability values of two among the three time windows and of the determined probability value of a third time window as a measure of the background light.

5 . Device as claimed in claim 2 ,
wherein the evaluation device determines the probability values of three time windows which are directly consecutive in terms of time, a beginning of a first time window among the three time windows being defined by a time of emission of a light pulse, wherein the evaluation device determines the value of a time of flight of the light pulse from the transmission device to the object and from the object to the reception device on the basis of the following formula:

T
TOF

=

T
P



ln


(

1
-

P
2

)

-

ln


(

1
-

P
3

)

ln


(

1
-

P
1

)

+

ln


(

1
-

P
2

)

-

2


ln


(

1
-

P
3

)

,

wherein the time of flight is designated by T TOF ,
wherein the pulse duration is designated by T p ,
wherein the determined probability values of the three time windows are designated by P 1 , P 2 and P 3 , and
wherein In is used for designating the natural logarithm.

6 . Device as claimed in claim 2 ,
wherein the evaluation device determines the probability values of more than three time windows, wherein the evaluation device identifies, on the basis of the probability values determined for the time windows, a time window comprising a start of a detection of a light pulse reflected at the object, wherein the evaluation device determines an averaged probability value as the measure of the background light from the probability values of those time windows which differ from the identified time window and from a time window which immediately follows the identified time window, and wherein the evaluation device determines the measure of the distance of the object on the basis of the determined probability values of the identified time window and of the subsequent time window as well as on the basis of the averaged probability value.

7 . Device as claimed in claim 6 ,
wherein the evaluation device identifies the time window comprising the start of the detection of the light pulse reflected at the object by determining the time window comprising the highest probability value and by comparison with adjacent time windows.

8 . Device as claimed in claim 6 ,
wherein the evaluation device determines a value of a time of flight of the light pulse from the transmission device to the object and from the object to the reception device on the basis of the following formula:

T
TOF

=

T
P



(

n
-
1

)

+

T
P



Assignees

• Fraunhofer Ges Forschung

Inventors

• Beer Maik
• Schrey Olaf
• Brockherde Werner
• Schwinger Alexander
• Hosticka Bedrich

Classifications

• G01S7/4863

  Detector arrays, e.g. charge-transfer gates · CPC title

• G01S17/14 Primary

  wherein a voltage or current pulse is initiated and terminated in accordance with the pulse transmission and echo reception respectively, e.g. using counters · CPC title

• G01S7/4876

  by removing unwanted signals (G01S7/495 takes precedence) · CPC title

• G01S17/10

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

• G01S7/4865 Primary

  Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487) · CPC title