Wind Noise Reduction Using Generalized Sidelobe Canceller
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Solution Overview
Problem
Existing devices with multiple microphones struggle to effectively reduce wind noise, as adaptive directional beamforming systems cannot identify and null wind noise due to its uncorrelated nature, leading to corrupted signal quality and often disabling beamforming in its presence.
Innovation Solution
A device and method utilizing a generalized sidelobe canceller with a blocking matrix filter and noise cancellation filter to produce speech and noise reference signals, which are then processed to generate a wind noise reduction signal, allowing for adaptive wind noise reduction while maintaining spatial noise cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive directional beamforming is used to reduce spatial noise, then signal quality in the direction of interest is improved, but wind noise is amplified because it is uncorrelated between microphones
Solution Approach 1:
The patent segments the noise reduction task into two independent parts: spatial noise cancellation using beamforming for correlated background noise, and wind noise reduction using a separate algorithm that processes the difference signal between microphones. This segmentation allows each algorithm to specialize in its respective noise type without interfering with the other, resolving the contradiction between maintaining beamforming performance and reducing wind noise.
Solution Approach 2:
The patent introduces an intermediary processing stage that computes the difference signal between the first and second microphone inputs before applying wind noise reduction. This intermediary difference signal serves as a mediator that isolates wind noise components while preserving the correlated spatial noise characteristics, enabling effective wind noise reduction without compromising beamforming's ability to cancel spatial background noise.
2Object-affected harmful factors
If beamforming is disabled in the presence of wind noise to avoid amplification, then wind noise amplification is avoided, but spatial noise cancellation capability is lost
Solution Approach 1:
The patent segments the noise handling into two parallel processing paths: one path maintains beamforming for spatial noise cancellation, while the other path processes the difference signal for wind noise reduction. This segmentation allows the system to retain spatial noise cancellation capability while independently addressing wind noise, eliminating the need to disable beamforming entirely.
Solution Approach 2:
The patent merges the outputs of the beamforming processor and the wind noise reduction processor to produce the final cleaned signal. By combining both processing paths, the system achieves both spatial noise cancellation and wind noise reduction simultaneously, resolving the contradiction between maintaining beamforming and avoiding wind noise amplification.
3Object-affected harmful factors
If additional filters are added to reduce wind noise, then wind noise reduction is improved, but device complexity increases
Solution Approach 1:
The patent makes the difference signal processing path serve multiple functions: it provides wind noise reduction through the main algorithm, and also generates error signals for adaptive feedback to refine the beamforming weights. This multi-functionality reduces the need for separate dedicated filters, thereby reducing overall device complexity while maintaining effective wind noise reduction.
Solution Approach 2:
The patent implements feedback mechanisms where the output of the wind noise reduction processing is fed back to adjust the beamforming weights adaptively. This feedback loop allows the system to learn from the processed difference signal and refine its spatial filtering, reducing the need for additional complex filters while improving wind noise reduction effectiveness.
Data Source
AI summary
A device for wind noise reduction and spatial noise reduction comprises a first microphone for capturing a nominal speech signal, and a second microphone for capturing a nominal noise signal. The device has a generalized sidelobe canceller for spatial noise reduction, comprising a blocking matrix filter configured to adaptively process the nominal speech signal to produce a speech cancellation signal, a first subtraction node for subtracting the speech cancellation signal from the nominal noise signal to produce a noise reference signal, a noise cancellation filter configured to adaptively filter the noise reference signal to produce a noise cancellation signal, and a second subtraction node for subtracting the noise cancellation signal from the nominal speech signal to produce a speech reference signal. The device has a wind noise reduction module for wind noise reduction, the wind noise reduction module comprising at least one filter derived from the blocking matrix filter of the generalized sidelobe canceller.