ToF Distance Sensing with Dynamic Peak Selection Under Interference
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Solution Overview
Problem
Conventional distance measurement methods using the direct time of flight (ToF) method struggle to effectively suppress interference from multiple vehicles and are vulnerable to falsification by malicious third parties altering light emission timings.
Innovation Solution
A distance measurement device with a time measurement unit, histogram generation unit, light source control unit, selection unit, and distance calculation unit dynamically changes the light source's driving state to select a peak based on histogram analysis, thereby suppressing interference and ensuring accurate distance calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If light emission timing is randomly changed to suppress interference, then interference from other distance measurement devices is reduced, but distance measurement data may be falsified by malicious third parties who perform different light emission following the light emission timing
Solution Approach 1:
The light source control unit dynamically changes the driving state of the light source based on histogram analysis. When multiple peaks are detected in the histogram, the system adjusts the light emission timing and characteristics to eliminate ambiguous distance measurements, thereby preventing falsification while maintaining interference suppression
Solution Approach 2:
The histogram generation unit continuously monitors the received light signals and feeds back information to the light source control unit. This feedback mechanism allows the system to detect multiple peaks indicating potential falsification and adjust the light emission accordingly, creating a closed-loop system that maintains measurement integrity
2Object-affected harmful factors
If conventional direct ToF method is used with random light emission timing, then interference suppression is partially achieved, but distance measurement precision deteriorates due to multiple peaks in histogram
Solution Approach 1:
The system dynamically adjusts the light source driving state based on real-time histogram analysis. When multiple peaks are detected, the light source control unit modifies emission parameters to consolidate peaks, thereby maintaining interference suppression while restoring measurement precision
Solution Approach 2:
The light source control unit changes driving parameters such as emission timing and pulse characteristics based on histogram peak detection. This parameter adjustment eliminates multiple peaks caused by interference while preserving the interference suppression benefit, achieving both goals simultaneously
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 device effectively suppresses interference from other distance measurement devices and reduces the risk of falsification, while also minimizing circuit area and power consumption.
Implementation Method 1
light emitted from a light source and then reflected by an object to be measured is received by a light receiving element
Implementation Method 2
a distance to the object is measured on the basis of a time from the emission of the light to the reception of the reflected light
Data Source
AI summary
Provided is a distance measurement device that includes a time measurement unit, a histogram generation unit, a light source control unit, a selection unit, and a distance calculation unit. The time measurement unit measures time information indicating a time from a light emission timing at which a light source emits light to a light reception timing at which a light receiving element receives light. The histogram generation unit generates a histogram based on the time information. The light source control unit dynamically changes a driving state of the light source. The selection unit selects one peak based on the driving state of the light source in a case where a plurality of peaks are detected in the histogram in one frame. The distance calculation unit calculates a distance (D) to an object based on the selected peak.