Optical Fiber Object Presence Detection Using Time-Distance Graphs
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Solution Overview
Problem
The existing optical fiber measurement system for road infrastructure struggles to accurately detect the presence of vehicles in specific lanes due to mixed detection of signals from both lanes, leading to potential inaccuracies in traffic information.
Innovation Solution
An object presence detection system that processes time-distance graph information from distributed sensing portions to detect impulse responses and determine the presence and direction of moving objects, using methods like Angle-of-Arrival and Time Difference of Arrival, to isolate and accurately identify vehicles in individual lanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If an optical fiber sensor is used to detect vibrations along the movement path, then the detection coverage is extended, but the measurement precision deteriorates because signals from both lanes are mixed
Solution Approach 1:
The patent segments the optical fiber sensor into multiple distributed sensing portions along the movement path. Each sensing portion independently detects vibrations in its local region, allowing the system to distinguish between vehicles in different lanes by analyzing which specific sensing portions detect the vibration signals.
Solution Approach 2:
The patent introduces a temporal dimension by analyzing the time difference of arrival (TDOA) of vibration signals at different sensing portions. By measuring when vibrations arrive at each sensing portion, the system can determine the direction of vehicle movement and distinguish between vehicles in opposite lanes, transforming a 1D spatial detection problem into a 2D spatio-temporal analysis.
2Device complexity
If raw vibration signals from both lanes are detected in a mixed manner, then the device complexity is reduced, but the reliability of traffic information deteriorates
Solution Approach 1:
The patent employs feedback mechanisms where the system continuously analyzes the time difference of arrival at distributed sensing portions and uses this information to determine vehicle direction. This feedback loop allows the system to dynamically distinguish between lanes and provide accurate traffic information for each lane separately, improving reliability without significantly increasing device complexity.
3Ease of operation
If the optical fiber detects traffic information in a mixed manner for both lanes, then the ease of operation is maintained, but the measurement precision for individual lane detection deteriorates
Solution Approach 1:
The patent enables the system to automatically distinguish between lanes using the inherent time difference of arrival information from the distributed sensing portions. The system self-calibrates and self-distinguishes lane information without requiring external intervention or complex manual configuration, maintaining ease of operation while achieving precise individual lane detection through automated spatio-temporal analysis.
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 enables more accurate detection of vehicle presence and direction, improving the precision of traffic information generation and reducing the likelihood of misidentification across lanes.
Implementation Method 1
uses an optical fiber sensor, which is an optical transmission line laid along the movement path of a moving body, and includes a detector that detects back-scattered light generated in response to the optical pulse in the optical fiber sensor
Data Source
AI summary
An object of the present disclosure is to provide an object presence detection system, an object presence detection method and a non-transitory computer readable medium capable of detecting the presence of an object more accurately. In one aspect, an object presence detection system includes at least one memory configured to store instructions; and at least one processor configured to execute the instructions to: obtain time-distance graph information of an oscillation signal for each distributed sensing portion, while the oscillation signal is acquired by the plurality of distributed sensing portions and is induced by traffic of a moving object, detect impulse response using the time-distance graph information measured by the plurality of distributed sensing portions, and detect a presence of the moving object, which includes moving direction information of the moving object, using the impulse response information in the time-distance graph information.