Array Microphone Aperture Predistortion for Directivity
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Solution Overview
Problem
Array microphones experience suboptimal coverage due to changes in apparent aperture when steered, leading to the capture of undesired audio sources and failure to pick up all desired sources, as the apparent aperture differs from the base aperture at various steering vectors.
Innovation Solution
The system predistorts the aperture of array microphones using mask conditioning and optimal microphone element selection to regularize the apparent aperture, minimizing the number of elements used and improving directivity across different steering vectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If array microphones are steered to focus on specific audio sources, then directivity is improved, but the apparent aperture changes causing suboptimal coverage and capture of undesired audio
Solution Approach 1:
The system applies predistortion to the aperture before beamforming occurs. By pre-modifying the aperture characteristics based on the intended steering direction, the system compensates for the expected aperture distortion that would normally occur during steering, thereby maintaining both directivity and coverage
2Device complexity
If the number of microphone elements is reduced to minimize device complexity, then manufacturing cost decreases, but aperture regularization and directivity performance deteriorate
Solution Approach 1:
The system changes the operational parameters of the microphone elements through predistortion weighting and selection. By dynamically adjusting which elements are active and how their signals are weighted, the system achieves effective aperture regularization without requiring a fixed large number of physical elements, thus reducing device complexity while maintaining directivity
3Power
If all microphone elements are used for beamforming, then signal strength is improved, but computational complexity and processing time increase
Solution Approach 1:
The system extracts and selects only the most relevant microphone elements for each beamforming operation based on the steering direction and aperture requirements. By removing unnecessary elements from the processing chain through selection algorithms, the system reduces computational complexity and processing time while maintaining sufficient signal strength through optimal element utilization
Data Source
AI summary
Array microphone systems and methods for enabling predistortion of the aperture of an array microphone at various steering vectors are provided. The predistortion of the aperture can regularize the apparent aperture of the array microphone to be closer to that of the base aperture of the array microphone, while minimizing the number of microphone elements used. Improved directivity and more optimal pickup and capture of sound in the environment may result through the use of these systems and methods, which can help to avoid undesired noise and/or to more efficiently cover audio sources.