Multi-Threshold Distance Sensing for Single-Photon Range Accuracy
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Solution Overview
Problem
Existing distance measuring devices have limitations in extending the range of measurable distances, achieving high point cloud density, and maintaining distance accuracy, particularly in environments with high external light interference.
Innovation Solution
A distance measuring device equipped with a light-receiving element capable of single-photon detection, an extraction section, an amplification section, and at least three comparators with different threshold voltages, allowing for extended range measurement and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional light-receiving elements are used, then device complexity is reduced, but measurement precision and detectable distance range are limited
Solution Approach 1:
The patent segments the signal processing function by dividing the comparator stage into multiple comparators with different threshold voltages. This allows the system to detect different photon count levels (single-photon, multi-photon events) separately, improving measurement precision while keeping each individual comparator relatively simple
Solution Approach 2:
The patent dynamically adjusts the threshold voltages of the comparators based on the expected photon count for the current measurement range. This dynamic adaptation allows the system to maintain high measurement precision across varying distances without requiring a completely different device configuration
2Length of stationary object
If single-photon detection is implemented, then measurable distance range is extended, but susceptibility to false signals from external light increases
Solution Approach 1:
The patent segments the detection process into multiple threshold levels using multiple comparators. By comparing the signal against different thresholds (Vth1, Vth2, Vth3), the system can distinguish between genuine single-photon events and false signals from external light, thereby extending measurable distance while maintaining reliability
Solution Approach 2:
The patent implements feedback mechanisms where the detection results from multiple comparators are综合分析 to determine the final measurement. The system uses the outputs from comparators with different thresholds to verify and validate single-photon detection events, reducing false positives from external light interference
3Quantity of substance
If multiple comparators with different threshold voltages are used, then point cloud density increases, but device complexity increases
Solution Approach 1:
The patent uses multiple comparators with different threshold voltages to segment the photon detection into multiple categories (single-photon, multi-photon events). Each comparator contributes to generating point cloud data, thereby increasing overall point cloud density while keeping each individual comparator circuit relatively simple and modular
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 achieves extended range measurement, increased point cloud density, and enhanced distance accuracy by minimizing the influence of false signals through single-photon detection and advanced signal processing.
Implementation Method 1
a light-receiving element that is able to achieve single-photon detection and that generates an analog output that varies with the number of simultaneously received photons
Data Source
AI summary
A distance measuring device is capable of extending the range of measurable distance and includes a light-receiving element, an extraction section, an amplification section, and at least three comparators. The light-receiving element is able to achieve single-photon detection and generates an analog output that varies with the number of simultaneously received photons. The extraction section extracts high-frequency components of an output of the light-receiving element. The amplification section amplifies an output of the extraction section. The first comparator, the second comparator, and the third comparator receive supply of an output from the amplification section and have different threshold voltages. The threshold voltage (third threshold voltage) set for a predetermined comparator (third comparator) is a threshold voltage (Vth1) corresponding to single-photon detection in at least a part of a measurement period. The distance measuring device corrects a provisional time lag so as to cancel a time walk error.