Tetrahedral Microphone Array for Acoustic Source Localization
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Solution Overview
Problem
Existing sound source localization systems are poorly suited for external use due to complex microphone positioning and sensitive weather conditions, and require precise antenna positioning for accurate sound mapping.
Innovation Solution
A tetrahedral microphone array with MEMS microphones and an optical sensor, integrated into a robust, weather-protected antenna structure, utilizing time difference of arrival calculations and phase transformation methods for precise sound source localization and mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a network of spatially offset microphones is used for sound source localization, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system divides the sound source localization task into multiple measurement points distributed across the monitored area. Each measurement point contains a simplified microphone array (e.g., tetrahedral configuration with 4 microphones), and the collective data from all segments enables comprehensive 3D localization without requiring a single complex centralized array.
Solution Approach 2:
The patent transitions from 2D microphone arrays to 3D spatial distribution of measurement points. By positioning multiple simplified arrays at different locations in three-dimensional space, the system achieves accurate sound source localization throughout the volume without requiring each individual array to be complex.
2Adaptability or versatility
If measurement systems are deployed for external use, then adaptability is improved, but reliability deteriorates due to weather sensitivity
Solution Approach 1:
Each measurement point is enclosed in a protective housing that shields the microphones and electronics from weather conditions while allowing acoustic signals to pass through. This protective enclosure enables reliable operation in outdoor environments without compromising the measurement capability.
Solution Approach 2:
The system uses acoustic wave propagation through the environment as an intermediary to transfer sound information from the source to the protected measurement points. This allows the measurement system to remain isolated from weather conditions while still capturing environmental sound data accurately.
3Measurement precision
If precise antenna positioning is required for accurate sound mapping, then measurement precision is improved, but ease of operation worsens
Solution Approach 1:
Each measurement point automatically performs self-calibration and self-positioning using the acoustic signals themselves. The system estimates the position of each measurement point relative to the sound source by analyzing the acoustic arrival times, eliminating the need for manual surveying and precise positioning of each antenna.
Solution Approach 2:
The patent replaces mechanical positioning systems (tripods, surveying equipment, precise mounting structures) with computational positioning methods. The 3D coordinates of each measurement point are determined through acoustic signal processing and mathematical algorithms rather than physical positioning mechanisms.
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 system provides accurate and robust sound source localization with reduced parallax errors and improved weather resistance, enabling effective noise pollution monitoring and mapping in various environments.
Implementation Method 1
computer processing determines the direction of arrival of a sound wave by calculating its capture times by each microphone to deduce the delay (τ) or the difference in arrival times (TDOA) recorded between two microphones
Implementation Method 2
an imaging lens fixed to the upper part on one side of the spherical body so as to be exposed upwards, which allows an optical image to be taken reflected in the reflecting mirror
Data Source
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AI summary
The present invention relates to a system for locating at least one sound source, comprising an acoustic antenna consisting of four microphones positioned at the vertices of a tetrahedron, and an electrical signal processing circuit for calculating information representative of the direction of the sound source relative to the acoustic antenna. The acoustic antenna further comprises at least one imaging means (46), the optical centre of which coincides with the geometric centre of said antenna.