Bridge Vehicle Detection Using Blind Source Separation

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Solution Overview

Problem

Existing vehicle detection algorithms, such as the AVD algorithm, struggle to accurately identify and discriminate individual vehicles in complex traffic situations, including parallel traffic, serial traffic, and mixed traffic models, due to the combination of vehicle types and overlapping vibrations.

Innovation Solution

A vehicle detection apparatus and method that utilizes blind source separation (BSS) to separate and adjust oscillation signals from multiple sensors on a bridge, allowing for the accurate identification and counting of individual vehicles on parallel lanes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple sensors are arranged in each lane to detect axle intervals and vehicle types, then vehicle classification accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvevehicle classification accuracyVSAvoidsensor arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The bridge is divided into multiple detection sections with sensors arranged at different positions (e.g., under the bridge at specific intervals). Each sensor detects vibrations from vehicles passing through its section, and the detection results from multiple sections are combined to identify vehicle types based on axle intervals and vibration patterns, reducing the need for dense sensor coverage in any single location

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A single sensor arrangement serves multiple detection functions simultaneously: detecting axle intervals, classifying vehicle types, and monitoring traffic flow. The vibration detection system is designed to extract multiple pieces of information from the same sensor data, eliminating the need for separate detection systems for each function

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Speed

If AVD algorithm uses minimum time headway threshold to distinguish vehicles, then processing speed is improved, but vehicle discrimination accuracy deteriorates in parallel and mixed traffic scenarios

Engineering Contradiction:
Improvevehicle detection speedVSAvoidvehicle discrimination accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The detection system transitions from relying solely on time-based separation (time headway threshold) to incorporating spatial dimension information. Sensors are positioned at multiple locations across the bridge width and length, detecting vibrations from different spatial zones. This spatial distribution allows the system to distinguish between vehicles in parallel lanes and serial traffic simultaneously, maintaining high detection speed while improving discrimination accuracy in complex traffic patterns

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system uses multiple detection parameters beyond time headway, including vibration amplitude, frequency characteristics, and spatial distribution of vibration signals. By analyzing changes in these parameters across multiple sensor locations, the system can accurately distinguish vehicles even when time headway is below the minimum threshold, resolving the contradiction between detection speed and accuracy

Inventive Principle:
Principle #35Parameter changes

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 proposed solution effectively detects and identifies individual vehicles in complex traffic scenarios by separating specific oscillation signals for each lane, improving the accuracy of vehicle counting and classification.

Implementation Method 1

sensors, respectively, each provided for each lane of a bridge that includes a plurality of lanes running in parallel and capable of sensing oscillation of the bridge induced by an individual axle of a vehicle passing on the lane

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentUS12236777B2Vehicle detection apparatus, method and program
Publication Date: 2025.02.25 NEC CORP
  • US12236777B2 patent drawing
  • US12236777B2 patent drawing
  • US12236777B2 patent drawing

AI summary

An apparatus includes a signal acquisition part acquires oscillation signals from sensors provided under lanes of a bridge and close to an expansion joint, a signal separation part applies BSS to the oscillation signals to estimate source oscillation signals respectively separated in the plurality of lanes, and adjusts amplitude of the source oscillation signals to output amplitude adjusted oscillation signals, and a vehicle estimation part estimates, from the amplitude adjusted oscillation signal, a response oscillation due to a vehicle passing on the lane of interest to detect and count vehicles passing on the lane.