Time-of-Flight Distance Measurement With Dual-Interval Sampling

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Solution Overview

Problem

Pulse modulation in time-of-flight distance measuring techniques faces challenges in high dynamic range applications, particularly in accurately measuring distance and regulating the impact of background light on distant information.

Innovation Solution

A time-of-flight distance measuring method and system that intermittently transmits pulses and adjusts sampling intervals or pulse patterns to enhance high dynamic range sampling, using a TOF sensor for continuous signal sampling and phase shift calculations to determine distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If pulse modulation is used for time-of-flight distance measurement, then the measurement mechanism is simple, but the accuracy of time measurement must be very high and the range of distance measurement is limited in high dynamic range applications

Engineering Contradiction:

Improvemeasurement mechanism complexityVSAvoidtime measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent divides the distance measurement process into multiple segments by implementing multiple sampling stages with different integration times. The first sampling stage uses a shorter integration time for near objects, while the second sampling stage uses a longer integration time for distant objects. This segmentation allows the system to measure a wider distance range without requiring extremely high time measurement precision across the entire range.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent dynamically adjusts the sampling integration time based on the detected signal strength and distance requirements. The system switches between different sampling modes (first sampling with shorter integration time, second sampling with longer integration time) depending on the measurement conditions. This dynamic adaptation enables the system to maintain measurement accuracy across varying distances without requiring uniformly high precision throughout.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If pulse modulation is used for time-of-flight distance measurement, then the measurement mechanism is simple, but the regulation of background light impact on distant information is insufficient in high dynamic range applications

Engineering Contradiction:

Improvemeasurement mechanism complexityVSAvoidbackground light impact

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the signal sampling process into multiple stages with different integration times. The first sampling stage with shorter integration time captures signals from nearer objects while minimizing background light accumulation. The second sampling stage with longer integration time captures signals from distant objects where background light impact is more significant. This segmented approach allows differential regulation of background light impact across different distance ranges.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the integration time parameter between different sampling stages to regulate background light impact. By using a shorter integration time in the first sampling stage and a longer integration time in the second sampling stage, the system adapts to different signal strengths and background light conditions. This parameter adjustment enables effective background light rejection while maintaining sensitivity for distant object detection.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances the effectiveness of high dynamic range sampling by modulating the sampling interval or pulse pattern, improving distance measurement accuracy and reducing the influence of background light noise.

Implementation Method 1

measures the distance of a target using the time difference between the transmission and reception of an optical pulse

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Implementation Method 2

the plurality of first pulses are reflected by a target to generate a plurality of first reflected signals

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS12436244B2Time-of-flight distance measuring methods and related distance measuring systems

Publication Date: 2025.10.07 SHENZHEN GOODIX TECH CO LTD

AI summary

A time-of-flight distance measuring system includes: intermittently transmitting a plurality of first pulses, wherein the plurality of first pulses are reflected by a target to generate a plurality of first reflected signals; using a TOF sensor to selectively perform a first signal sampling or a second signal sampling upon the plurality of first reflected signals respectively to generate a first sampling result, wherein there is a first time difference between a starting time point of the first signal sampling and a transmitting time point of the corresponding first pulse, and the first signal sampling lasts for a first predetermined time, and there is a second time difference between a starting time point of the second signal sampling and a transmitting time point of the corresponding first pulse, and the second signal sampling lasts for second predetermined time, and the first time difference is smaller than the second time difference.