Pulsed-based time of flight methods and system

Patent metadata

Field	Value
Publication number	US-10585176-B2
Application number	US-201715708294-A
Country	US
Kind code	B2
Filing date	Sep 19, 2017
Priority date	Sep 19, 2017
Publication date	Mar 10, 2020
Grant date	Mar 10, 2020

Abstract

A time of flight sensor device is provided that is capable of generating accurate information relating to propagation time of emitted light pulses using a small number of measurements or data captures. By generating pulse time of flight information using a relatively small number of measurement cycles, object distance information can be generated more quickly, resulting in faster sensor response times. Embodiments of the time of flight sensor can also minimize or eliminate the adverse effects of ambient light on time of flight measurement. Moreover, some embodiments execute time of flight measurement techniques that can achieve high measurement precision even when using relatively long light pulses having irregular, non-rectangular shapes.

First claim

What is claimed is:

1. A time of flight sensor device, comprising:
an emitter component configured to emit a first light pulse at a first time that is delayed relative to a start of a first measuring sequence by a first delay, and a second light pulse at a second time that is delayed relative to a start of a second measuring sequence by a second delay longer than the first delay;
a photo-sensor component comprising a photo-detector, the photo-detector comprising
a photo device configured to generate electrical energy in proportion to a quantity of received light, and
a measuring circuit configured to
capture a first portion of the electrical energy proportional to a first leading portion of a first received reflected light pulse corresponding to the first light pulse, and a second portion of the electrical energy proportional to a first trailing portion of the first received reflected light pulse, wherein the first leading portion and the first trailing portion are divided at a first sampling time that is delayed relative to the start of the first measuring sequence by a third delay, and
capture a third portion of the electrical energy proportional to a second leading portion of a second received reflected light pulse corresponding to the second light pulse, and a fourth portion of the electrical energy proportional to a second trailing portion of the second received reflected light pulse, wherein the second leading portion and the second trailing portion are divided at a second sampling time that is delayed relative to the start of the second measuring sequence by the third delay; and

a distance determination component configured to determine a propagation time for the first light pulse or the second light pulse based on a first measured value of the first portion, a second measured value of the second portion, a third measured value of the third portion, and a fourth measured value of the fourth portion.

2. The time of flight sensor device of claim 1 , wherein the distance determination component is configured to determine the propagation time based on a first difference between the first measured value and the second measured value, and a second difference between the third measured value and the fourth measured value.

3. The time of flight sensor device of claim 1 , wherein the distance determination component is configured to determine the propagation time tp based on

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Assignees

• Rockwell Automation Tech Inc

Inventors

• Boutaud Frederic
• Li Mei

Classifications

• 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

• G01S17/894

  Three-dimensional [3D] imaging with simultaneous measurement of time-of-flight at a two-dimensional [2D] array of receiver pixels, e.g. time-of-flight cameras or flash lidar · CPC title

• G01S7/497

  Means for monitoring or calibrating · CPC title

• G01S17/89

  for mapping or imaging · CPC title