Polyhedral Microphone Array for 3D Beampattern Control
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Solution Overview
Problem
Conventional spherical microphone arrays require a large number of microphones, leading to high implementation costs and complexity, while existing geometries struggle with efficient control of beampatterns in three-dimensional space without mechanical alterations.
Innovation Solution
A microphone array design utilizing a plurality of sensors mounted on an acoustically rigid polyhedron, enabling decomposition of audio signals into eigenbeams for higher-order harmonic expansions, allowing for precise control of beampatterns through eigenbeam processing and beamforming, reducing the need for multiple filters and enhancing computational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional spherical microphone arrays are used to achieve full 3-D control of beampatterns, then the beampattern can be steered to any direction in three-dimensional space without changing the shape of the pattern, but the number of microphones required increases significantly, leading to high implementation costs
Solution Approach 1:
The patent segments the continuous spherical surface into a polyhedral structure with discrete faces and vertices. Microphones are strategically placed at these geometric features rather than distributed continuously across the sphere. This segmentation allows the system to achieve 3-D beampattern control with a finite, reduced set of microphones by utilizing the geometric properties of the polyhedron to define eigenbeam patterns.
Solution Approach 2:
The patent transitions from traditional spherical coordinate systems to polyhedral geometry, introducing a new dimensional framework for array configuration. By using the faces, edges, and vertices of a polyhedron as the structural basis, the system achieves 3-D spatial control through a different geometric paradigm that requires fewer sensors while maintaining full directional capability.
2Adaptability or versatility
If conventional spherical microphone arrays are used to achieve full 3-D control of beampatterns, then directional patterns can be varied over a wide range with software control, but the implementation complexity and cost increase due to the large number of microphones required
Solution Approach 1:
The patent segments the complex continuous spherical array into a discrete polyhedral structure with a finite number of strategic microphone positions. This segmentation simplifies the overall system architecture by replacing a densely packed continuous array with a sparse discrete configuration, reducing both the number of components and the complexity of their interconnections while preserving 3-D control capability.
Solution Approach 2:
The patent changes the fundamental geometric parameters of the array configuration from spherical coordinates to polyhedral geometry. By altering the spatial arrangement parameters to match the symmetric properties of regular polyhedra, the system achieves simplified mathematical formulations for beamforming and eigenbeam decomposition, reducing computational complexity while maintaining adaptability.
3Measurement precision
If a large number of microphones are used in spherical arrays to achieve accurate auditory scene representation, then full 3-D control is achieved, but the implementation costs and processing requirements increase significantly
Solution Approach 1:
The patent segments the continuous spherical measurement surface into discrete polyhedral elements, placing microphones at vertices and face centers. This segmentation allows accurate sampling of the acoustic field by capturing information at strategically located points that represent the geometric structure, achieving precise auditory scene representation with fewer sensors through intelligent spatial sampling.
Solution Approach 2:
The patent creates a universal polyhedral framework that serves multiple functions simultaneously: it defines the geometric structure for microphone placement, establishes the basis for eigenbeam decomposition, provides the framework for 3-D beamforming, and enables accurate auditory scene representation. This multi-functional geometric structure reduces the need for additional components while maintaining measurement precision.
Data Source
AI summary
A microphone array-based audio system that supports representations of auditory scenes using second-order (or higher) harmonic expansions based on the audio signals generated by the microphone array. In one embodiment, a plurality of audio sensors are mounted on the surface of an acoustically rigid polyhedron that approximates a sphere. The number and location of the audio sensors on the polyhedron are designed to enable the audio signals generated by those sensors to be decomposed into a set of eigenbeams having at least one eigenbeam of order two (or higher). Beamforming (e.g., steering, weighting, and summing) can then be applied to the resulting eigenbeam outputs to generate one or more channels of audio signals that can be utilized to accurately render an auditory scene.