TOF Sensor Interference Suppression via Subframe Timing Control
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Solution Overview
Problem
Time of Flight (TOF) sensors used for distance measurement in vehicles experience interference from irradiation light and reflected light, leading to reduced accuracy, especially in scenarios with multiple vehicles performing automatic operations.
Innovation Solution
A distance measurement device with a light emitting unit, a light receiving unit, and a control unit that emits irradiation light in a controlled manner, including multiple subframes with varying timing and constant intervals, to minimize interference between frames and subframes, and optionally uses a random number generation unit to further adjust emission timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple TOF sensors are mounted in the vehicle to measure distance to objects in each direction, then the coverage and functionality of automatic operation is improved, but interference between sensors increases
Solution Approach 1:
The patent implements periodic action by dividing the measurement period into multiple frames, each containing multiple subframes with different emission timing patterns. The control unit alternates between these frames, creating a periodic structure that allows different sensors to be active at different times within each period, thereby reducing mutual interference while maintaining comprehensive coverage.
Solution Approach 2:
The patent applies dynamics by making the emission timing of subframes variable rather than fixed. The control unit dynamically adjusts the timing of subframe emissions based on the frame number and predetermined patterns, allowing the system to adaptively manage interference between multiple sensors while maintaining measurement accuracy.
2Measurement precision
If irradiation light is emitted continuously for accurate distance measurement, then measurement precision is improved, but interference with other vehicles and sensors increases
Solution Approach 1:
The patent segments the continuous emission process into discrete frames, each containing multiple subframes with specific timing patterns. This segmentation allows the system to control precisely when light is emitted, enabling accurate measurement while minimizing interference with other vehicles by creating structured gaps and timing variations between emissions.
Solution Approach 2:
The patent changes the timing parameter of light emission dynamically. By varying the start timing of subframes within each frame and adjusting the overall frame rate, the system maintains measurement precision through multiple samples while reducing interference by creating temporal differentiation that allows other vehicles to distinguish between different light sources.
3Device complexity
If subframes are emitted at fixed intervals for simple control, then device complexity is reduced, but interference suppression capability is limited
Solution Approach 1:
The patent implements periodic action through the frame-subframe structure where subframes are emitted at regular intervals within each frame, creating a predictable periodic pattern. This periodicity simplifies the control mechanism while enabling effective interference suppression through the variation between different frames and the structured timing within frames.
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
The solution effectively suppresses interference, maintaining the accuracy of distance measurements in environments with multiple TOF sensors, improving the reliability of automatic vehicle operations.
Implementation Method 1
a light emitting unit configured to emit irradiation light
Implementation Method 2
a light receiving unit configured to receive reflected light which is the irradiation light reflected by a target object
Implementation Method 3
time of flight (TOF) sensor that performs distance measurement for measuring a distance to a target object by emitting irradiation light and receiving reflected light
Data Source
AI summary
The present technology relates to a distance measurement device and a distance measurement method that can easily suppress interference.A first frame being a period that a distance to a target object is calculated includes a plurality of subframes being periods that irradiation light is emitted, and the emission of the irradiation light is controlled so that timing of head subframes differs between a first frame and a second frame following the first frame, and intervals between the subframes become constant during the period of the first frame. The present technology can be applied to a case where distance measurement for measuring a distance is performed.