Audio Encoder for Wind Noise Reduction in Microphone Arrays
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Solution Overview
Problem
Directional audio systems suffer from increased wind noise in the low frequency range of beamformed audio signals, which traditional methods fail to effectively mitigate without compromising audio directionality or introducing additional noise issues.
Innovation Solution
An audio encoding and decoding system that combines a beamformed audio signal with a 'hidden' representation of a non-beamformed audio signal, where the low frequency portion of the non-beamformed signal is modulated to a high frequency range above the audible range, allowing for selective reduction of wind noise in the decoded audio signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If beamforming is applied to directional audio recording, then audio directionality is improved, but wind noise in the low frequency range increases
Solution Approach 1:
The audio signal is segmented into different frequency ranges (low frequency and mid/high frequency). Beamforming is applied selectively to mid and high frequencies where it provides directional control, while low frequencies are processed separately to avoid wind noise amplification. This segmentation allows the system to achieve directional audio recording without the harmful low-frequency wind noise that plagues traditional beamforming approaches.
2Object-affected harmful factors
If wind noise reduction is applied to beamformed audio signal, then wind noise is reduced, but audio directionality is compromised
Solution Approach 1:
The system segments the frequency spectrum and applies different processing strategies to different bands. Low frequency components are processed with wind noise reduction techniques, while mid and high frequency components maintain beamforming processing to preserve directionality. This frequency-dependent segmentation resolves the contradiction by allowing wind noise reduction without compromising the directional information carried in higher frequencies.
3Ease of manufacture
If traditional beamforming is used, then audio directionality is achieved, but additional noise issues are introduced
Solution Approach 1:
The system segments the audio processing into frequency-specific paths. By applying beamforming only to mid and high frequency ranges where directional information is most valuable and where microphone noise is less problematic, while handling low frequencies separately with noise reduction techniques, the system achieves directional audio recording without introducing the additional noise issues that arise from applying uniform beamforming across all frequencies.
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 effectively reduces wind noise in the low frequency range of beamformed audio signals while maintaining audio directionality, ensuring that the noise reduction is only applied when needed, and the hidden signal remains inaudible when not processed.
Implementation Method 1
The selected audio signal is processed to modulate the selected audio signal based on a high frequency carrier signal to generate a high frequency signal
Data Source
AI summary
An audio system encodes and decodes audio captured by a microphone array system in the presence of wind noise. The encoder encodes the audio signal in a way that includes beamformed audio signal and a “hidden” representation of a non-beamformed audio signal. The hidden signal is produced by modulating the low frequency signal to a high frequency above the audible range. A decoder can then either output the beamformed audio signal or can use the hidden signal to generate a reduced wind noise audio signal that includes the non-beamformed audio in the low frequency range.