3D Tetrahedral Microphone Array for Sound Source Localization
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Solution Overview
Problem
Miniaturized robots face challenges in localizing sound sources in three-dimensional space with minimal microphones and minimizing dead space, as existing methods require multiple microphones and involve significant computational complexity, making real-time localization difficult.
Innovation Solution
A hybrid sound source localization method using a Generalized Cross-Correlation (GCC)-Phase Transform (PHAT) algorithm to determine the direction and Steered Response Power (SRP)-PHAT algorithm to accurately localize the sound source, with four microphones disposed at the corners of an imaginary tetrahedron to minimize dead space and reduce computational load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If eight or more microphones are arranged in a cube form to localize sound source in three-dimensional space using GCC-PHAT algorithm, then sound source localization accuracy is improved, but device complexity and number of microphones increase
Solution Approach 1:
The patent transitions from two-dimensional planar microphone arrays to three-dimensional tetrahedral configuration. By positioning four microphones at the vertices of a tetrahedron in 3D space, the system achieves volumetric coverage and eliminates dead zones present in planar arrangements, enabling accurate sound source localization in three-dimensional space with fewer microphones
Solution Approach 2:
The patent pre-calculates and stores transfer function matrices and their inverses for different microphone pairs and sound source positions. This preliminary computation enables real-time sound source localization by simply comparing current microphone signals with pre-stored reference data, significantly reducing online computational complexity
2Measurement precision
If SRP-PHAT algorithm is used to achieve better sound source localization performance, then measurement precision is improved, but computational complexity increases making real-time processing difficult
Solution Approach 1:
The patent pre-calculates transfer function matrices H(f,θ,φ) and their inverses for all possible sound source positions in three-dimensional space before operation. These pre-computed matrices are stored in memory, allowing the system to perform rapid sound source localization by simply correlating current microphone signals with pre-stored reference patterns, eliminating the need for complex real-time matrix inversions
Solution Approach 2:
The patent creates a virtual acoustic model by storing transfer function characteristics for various sound source positions in advance. Instead of performing complex acoustic calculations in real-time, the system copies and compares current microphone signal patterns against the pre-stored virtual acoustic environment, achieving fast and accurate sound source localization through pattern matching
3Device complexity
If four microphones are disposed in a plane to reduce device complexity, then number of microphones is reduced, but dead space increases reducing localization capability
Solution Approach 1:
The patent positions four microphones at the vertices of a tetrahedron in three-dimensional space rather than arranging them in a two-dimensional plane. This 3D configuration ensures that microphone pairs exist in multiple spatial orientations, providing coverage for sound sources from all directions including above and below the robot, thereby eliminating the dead zones inherent in planar arrangements
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
Enables rapid and accurate sound source localization in three-dimensional space with minimal microphones, reducing dead space and processing complexity, allowing for real-time direction determination and precise positioning.
Implementation Method 1
a microphone unit, implemented by a plurality of microphones, picks up a sound from a three-dimensional space
Implementation Method 2
determining a direction of the sound source using difference in sound arrival times at a plurality of sensors, i.e., Time-Difference Of Arrivals (TDOAs) between sensors
Data Source
AI summary
An apparatus and method for localizing a sound source in a robot are provided. The apparatus includes a microphone unit implemented by one or more microphones, which picks up a sound from a three-dimensional space. The apparatus also includes a sound source localizer for determining a position of the sound source in accordance with Time-Difference of Arrivals (TDOAs) and a highest power of the sound picked up by the microphone unit. Thus, the robot can rapidly and accurately localize the sound source in the three-dimensional space with minimum dead space, using a minimum number of microphones.