Audio Decoder Wind Noise Reduction via Hidden Signal
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Solution Overview
Problem
Directional audio systems experience increased wind noise in the low frequency range of beamformed audio signals, which is undesirable and affects noise performance.
Innovation Solution
An audio encoding and decoding system that includes a 'hidden' representation of a non-beamformed audio signal, where the low frequency portion is modulated to a high frequency range or level-limited to reduce wind noise, allowing for selective processing to either reconstruct a reduced wind noise signal or output a fully beamformed signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If beamforming is applied to capture directional audio signals, then directionality and audio focus are improved, but wind noise in the low frequency range increases
Solution Approach 1:
The audio signal is segmented into frequency bands, with separate processing applied to low frequency components (prone to wind noise) and high frequency components. The system processes different frequency segments differently to maintain directionality while reducing wind noise.
Solution Approach 2:
An intermediary signal processing stage is introduced between the beamforming process and the final audio output. This intermediary stage includes noise reduction modules that act as mediators to remove wind noise while preserving the directional characteristics of the audio signal.
2Object-affected harmful factors
If wind noise reduction processing is applied to beamformed audio, then wind noise is reduced, but directionality and audio quality may be compromised
Solution Approach 1:
Different quality characteristics are applied locally to different frequency components. The low frequency band receives enhanced noise reduction treatment while the high frequency band maintains its directional characteristics, allowing each component to have optimized processing tailored to its specific characteristics.
Solution Approach 2:
The system changes processing parameters dynamically based on the frequency content and detected noise conditions. Processing strength, filter characteristics, and noise thresholds are adjusted as parameters to reduce wind noise while preserving audio quality and directionality.
3Object-affected harmful factors
If aggressive noise reduction is applied to eliminate wind noise, then wind noise is minimized, but audio fidelity and dynamic range are reduced
Solution Approach 1:
Instead of applying excessive noise reduction that would harm audio fidelity, the system applies partial noise reduction tailored to the specific characteristics of wind noise. The processing strength is optimized to remove only the harmful wind noise components while preserving legitimate audio content and dynamic range.
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
Effectively reduces wind noise in the low frequency range of beamformed audio signals while maintaining directionality, allowing for improved noise performance without compromising audio quality.
Implementation Method 1
the low frequency portion is modulated to a high frequency range
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.