ToF Sensor Interference Suppression via Dynamic Offset Timing

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Solution Overview

Problem

In environments where multiple Time-of-Flight (ToF) sensors overlap, interference occurs, leading to incorrect distance measurements due to overlapping light projection timings, resulting in delayed interference detection and reduced reliability of distance measurement results.

Innovation Solution

Implementing a system where multiple light projection timings are set and switched for each synchronization signal, allowing for timely adjustment of light projection timings to avoid interference, and using a comparison of distance measurement results with different offset times to determine interference and adjust accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If light projection timing is delayed or randomly changed after interference detection, then interference from other ToF sensors is suppressed, but undetectable time increases and measurement reliability decreases

Engineering Contradiction:

Improveinterference suppressionVSAvoidundetectable time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the light projection timing adjustable and switchable between fixed synchronization mode and offset mode. The system dynamically changes the projection timing based on detected interference conditions, allowing it to adapt between maintaining synchronization for normal operation and introducing offset for interference suppression, thereby reducing undetectable time while suppressing interference.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the timing parameter by introducing an offset time that shifts the light projection timing relative to the synchronization signal. This parameter change allows the system to avoid overlapping with other ToF sensors' projection timings, suppressing interference while maintaining continuous measurement capability and reducing undetectable time.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If light projection timing is fixed based on synchronization signal, then measurement timing is stable, but interference from other ToF sensors occurs due to overlapping projection timings

Engineering Contradiction:

Improvemeasurement timing stabilityVSAvoidinterference from other ToF sensors

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The system maintains stability through the synchronization signal while introducing dynamic adjustability via the offset time. The offset time can be modified based on interference detection, allowing the system to switch between stable synchronized operation and interference-avoiding offset operation, thus maintaining timing stability while eliminating interference.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies preliminary action by detecting interference conditions and adjusting the offset time in advance before interference occurs. By monitoring the environment and proactively changing the projection timing using offset, the system prevents interference from happening while maintaining stable measurement timing.

Inventive Principle:

Principle #10Preliminary action

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

This approach reduces undetectable time and enhances the reliability of distance measurements by immediately determining interference and adjusting the light projection timings, ensuring accurate measurements even in the presence of unknown ToF sensors.

Implementation Method 1

distance measurement by a ToF sensor has been performed in applications such as interaction with a user and obstacle detection by a mobile robot. The ToF sensor projects light and measures reflected light to perform distance measurement.

Methodology Applied

Scientific EffectTime of Flight: Time of Flight

Data Source

PatentUS20230288544A1Information processing device, information processing method, and program

Publication Date: 2023.09.14 SONY GROUP CORP

AI summary

An information processing device according to an embodiment includes: a distance measurement unit that performs distance measurement at a timing at which a plurality of set offset times are sequentially applied in a plurality of frames each corresponding to a synchronization signal, and outputs a distance measurement signal; and a distance measurement calculation unit that performs calculation based on the distance measurement signal and sequentially outputs a distance measurement result.