Bilateral Microphone Array Wind Noise Control
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Solution Overview
Problem
Bilateral microphone arrays face challenges in effectively controlling wind noise, which interferes with both far-field and near-field sound detection, impacting conversation assistance and remote communication quality.
Innovation Solution
A processor-controlled bilateral microphone array system that combines signals from four microphones to generate far-field and near-field signals, with adjustable filters to prioritize voice detection over wind noise, using omnidirectional and directional modes based on wind noise levels, and applying gain and high-pass filters to optimize sound sensitivity and noise rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the microphone array uses directional filtering to enhance far-field sound detection, then sensitivity to distant sounds improves, but wind noise interference increases
Solution Approach 1:
The system dynamically adjusts filter characteristics based on detected wind noise levels. When wind noise is detected, the processor modifies the filtering parameters in real-time to reduce wind noise passage while maintaining far-field sound detection capability. This dynamic adaptation resolves the contradiction by making the system responsive to environmental conditions rather than using fixed directional filtering.
Solution Approach 2:
The processor changes filtering parameters based on wind noise detection. By monitoring wind noise levels and adjusting filter characteristics accordingly, the system optimizes the balance between far-field sensitivity and wind noise rejection. This parameter adjustment allows the system to maintain measurement precision while reducing harmful wind noise effects.
2Object-affected harmful factors
If the microphone array uses omnidirectional filtering to capture all sounds equally, then wind noise rejection improves, but near-field voice detection sensitivity decreases
Solution Approach 1:
The system dynamically switches between omnidirectional and directional filtering modes based on wind noise conditions. When wind noise is detected, omnidirectional filtering is applied to reject wind noise. When wind noise is absent, directional filtering is used to enhance near-field voice detection. This dynamic mode switching resolves the contradiction by optimizing filter characteristics for current environmental conditions.
Solution Approach 2:
The processor periodically evaluates wind noise levels and adjusts filtering mode accordingly. This periodic assessment allows the system to transition between omnidirectional and directional modes, ensuring optimal performance for both wind noise rejection and near-field voice detection at different times based on environmental conditions.
3Reliability
If the system applies aggressive filtering to reduce wind noise, then audio quality improves, but conversation assistance capability deteriorates
Solution Approach 1:
The system applies different filtering strategies to different frequency ranges and signal types. For far-field conversation sounds, gentle filtering is applied to preserve speech quality and assistance capability. For wind noise frequencies, more aggressive filtering is applied to improve audio quality. This localized differentiation resolves the contradiction by tailoring filter aggressiveness to specific signal characteristics rather than applying uniform filtering.
Solution Approach 2:
The filtering aggressiveness is dynamically adjusted based on the detected signal type and wind noise conditions. When conversation is detected, the system reduces filtering aggressiveness to maintain conversation assistance capability. When wind noise is detected without conversation, more aggressive filtering is applied to improve audio quality. This dynamic adjustment resolves the contradiction between audio quality and conversation assistance.
Data Source
AI summary
A pair of earphones have microphone arrays each providing a plurality of microphone signals. A processor receives the microphone signals and applies a first set of filters to a subset of the plurality of microphone signals from each of the arrays, the first set of filters inverting the signals below a cutoff frequency, and provides the first-filtered signals and the remainder of the microphone signals from each of the arrays to a second set of filters. The processor uses the second set of filters to combine the signals to generate a far-field signal that is more sensitive to sounds originating a short distance away from the earphones than to sounds close to the earphones above the cutoff frequency and omnidirectional below the cutoff frequency, determines a level of wind noise present in the microphone signals, and adjusts the cutoff frequency as a function of the determined level of wind noise, and provides the far-field signal to the speakers for output.