Ranging Device Irregular Pulse Emission Interference
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Solution Overview
Problem
Existing ranging devices face interference issues due to synchronized light emission intervals, leading to decreased frame rates when multiple devices are used in proximity.
Innovation Solution
A ranging device with a light emission control unit that emits pulse light at irregular intervals, utilizing a light receiving unit to detect and convert light signals, and a count holding unit to manage exposure periods, ensuring interference suppression while maintaining frame rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light emission timing is set randomly to suppress interference between ranging devices, then interference is reduced, but the light emission interval is lengthened and frame rate decreases
Solution Approach 1:
The patent applies periodic action by dividing the detection period into multiple unit detection periods with regular intervals, while varying the number of pulses emitted in each unit detection period according to a predetermined pattern. This creates a structured emission sequence that maintains timing predictability for the receiver while introducing variability to suppress interference with other ranging devices, thus avoiding the frame rate penalty of completely random emission timing.
Solution Approach 2:
The patent implements dynamics by making the light emission interval variable rather than fixed or purely random. The control unit adjusts the number of pulses emitted in each unit detection period based on predetermined values, creating a dynamic emission pattern that adapts to suppress interference while maintaining efficient frame rates. This dynamic adjustment allows the system to optimize between interference suppression and productivity.
2Productivity
If the light emission interval is shortened to increase frame rate, then productivity improves, but interference with other ranging devices increases
Solution Approach 1:
By structuring the emission into periodic unit detection periods with predictable intervals, the system can maintain shorter overall emission intervals for higher frame rates while using controlled variation in pulse numbers within each period to suppress interference. The periodic structure ensures timing synchronization is maintained for accurate distance measurement despite the shortened intervals.
Solution Approach 2:
The patent maintains continuous useful action by ensuring that pulse emissions occur in every unit detection period without gaps, maximizing the utilization of the shortened emission interval. The varied pulse counts within each continuous period maintain interference suppression while keeping the overall frame rate high through uninterrupted measurement cycles.
3Device complexity
If multiple ranging devices operate simultaneously with the same light emission interval, then device complexity is reduced, but measurement precision deteriorates due to light interference
Solution Approach 1:
The patent uses periodic action with a predetermined pattern of varied pulse emissions in each unit detection period. This creates a recognizable signature for each ranging device that can be distinguished by the receiving device, allowing multiple devices to operate simultaneously with the same basic emission interval structure while maintaining measurement precision through pattern-based interference rejection.
Solution Approach 2:
The receiving device is pre-configured with knowledge of the predetermined emission pattern, allowing it to anticipate and correctly identify pulses from specific devices. This preliminary action of pattern recognition enables multiple devices to share the same frequency band without compromising measurement accuracy, as the receiver can distinguish between devices based on their unique emission patterns.
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 between ranging devices while preserving frame rate by controlling light emission intervals, enhancing accuracy and efficiency in distance measurement.
Implementation Method 1
a light receiving unit configured to detect a light signal including light emitted from the light emitting unit and reflected by an object in a measurement target region and convert the light signal into a pulse signal
Data Source
AI summary
A ranging device includes a light emission control unit configured to control a light emitting unit; a light receiving unit; an exposure period setting unit configured to set one of a plurality of detection periods to an exposure period of the light receiving unit for each emission of the pulse light; and a count holding unit configured to count and hold the number of the pulse signals in each of the exposure periods, wherein when each of the plurality of detection periods is set, the light emission control unit causes the pulse light to be emitted at irregular light emission intervals that are shorter than a length corresponding to a length of a unit detection period which is defined as a period from the emission of the pulse light to an elapse of the detection period having the latest start timing among the plurality of detection periods.