Non-coherent Noise Reduction in Multi-channel Audio Sensing
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Solution Overview
Problem
Conventional multi-microphone devices lack effective methods for reducing non-coherent noise, such as wind noise, which interferes with signal processing and results in low-quality recordings.
Innovation Solution
A non-coherent noise reduction method that involves detecting the presence of non-coherent noise, estimating its power and contour, and enhancing audio sensing signals based on this information to effectively suppress the noise without degrading signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If suppression-based methods are used to reduce wind noise, then noise reduction is achieved, but signal quality deteriorates
Solution Approach 1:
The patent segments the audio signal processing into multiple independent stages: wind noise detection, noise power estimation, noise contour derivation, and signal enhancement. Each stage processes specific characteristics of the wind noise separately, allowing precise control over what aspects of the signal are modified and preserving other important signal qualities.
Solution Approach 2:
The patent applies different processing strategies to different parts of the signal based on local characteristics. The noise contour estimator derives frequency-specific contours that adapt the suppression level to each frequency bin, ensuring that suppression is applied locally where wind noise is present while preserving signal quality in frequency regions where wind noise is absent or minimal.
2Device complexity
If conventional noise reduction methods are applied, then processing simplicity is maintained, but non-coherent noise cannot be effectively cancelled
Solution Approach 1:
The patent changes the parameters used for noise characterization from simple power spectral density (used in conventional methods) to include noise contours in the frequency domain. This parameter change allows the system to capture the non-stationary and non-coherent characteristics of wind noise, enabling effective cancellation while maintaining a relatively simple processing framework.
Solution Approach 2:
The patent introduces intermediate processing components (noise detector, noise power estimator, noise contour estimator) that act as mediators between the raw audio signal and the final enhanced output. These intermediaries transform the raw signal into processed representations that highlight wind noise characteristics, enabling effective suppression without requiring complex direct filtering approaches.
3Object-affected harmful factors
If wind noise reduction methods are applied, then noise suppression is achieved, but interference with other signal processing components occurs
Solution Approach 1:
The patent performs wind noise reduction as a preliminary step before other signal processing operations. By detecting and suppressing wind noise early in the processing chain, the method prevents wind noise from interfering with subsequent processing stages such as speech enhancement, beamforming, or acoustic echo cancellation, thereby maintaining compatibility with other signal processing components.
Solution Approach 2:
The patent employs feedback mechanisms where the noise detector continuously monitors the input signal for wind noise characteristics, and the noise contour estimator adjusts the suppression parameters based on the detected noise levels. This feedback loop ensures that suppression is dynamically adapted to current conditions, preventing over-suppression that could interfere with other signal processing operations.
Data Source
AI summary
A non-coherent noise reduction method, comprising: (a) receiving a plurality of input audio sensing signals by a processor, wherein the input audio sensing signals correspond to a plurality of channels responsive to sensing by a plurality of audio sensors; (b) detecting whether non-coherent noise exists in at least one of the channels by a non-coherent noise detector; (c) estimating at least one noise power of the non-coherent noise by a noise power estimator, if the non-coherent noise exists in at least one of the channels; (d) deriving at least one noise contour of the non-coherent noise by a noise contour estimator, if the non-coherent noise exists in at least one of the channels; and (e) enhancing the input audio sensing signals according to the noise power and the noise contour if the non-coherent noise exists in at least one of the channels.