Adaptive Microphone Array for Wind Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wind-induced noise significantly limits communication quality in microphone systems, particularly in outdoor and directional hearing aids, cell phones, and hands-free headsets, as existing solutions like windscreens are not effective in varying acoustic environments.
Innovation Solution
A method combining a constrained adaptive two-element differential microphone array with a multichannel parametric noise suppression scheme, allowing the microphone array to adjust its directional response to minimize wind noise and transition from directional to non-directional operation based on wind conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a directional microphone array is used to improve speech pickup, then communication quality is improved, but wind-induced noise increases significantly
Solution Approach 1:
The system dynamically adjusts the beamwidth parameter based on detected wind noise levels. When wind noise is detected, the beamwidth is widened to reduce sensitivity to wind-induced pressure changes while maintaining directional speech pickup capability. This dynamic adaptation resolves the contradiction by allowing the system to switch between narrowbeam mode (for speech clarity) and widebeam mode (for wind noise reduction).
Solution Approach 2:
The invention changes the operational parameters of the microphone array by adjusting the beamwidth parameter in response to wind conditions. The system monitors wind noise levels and modifies the beamforming parameters accordingly, transitioning from a fixed directional pattern to a variable pattern that can widen to exclude wind noise while maintaining speech directionality.
2Stability of the object's composition
If a fixed directional pattern is used to maintain consistent speech pickup, then directional performance is stable, but adaptability to varying wind conditions deteriorates
Solution Approach 1:
The system transitions from a static directional pattern to a dynamic one that automatically adjusts based on environmental conditions. The beamwidth parameter is modified in real-time according to wind noise detection, enabling the system to maintain stable speech pickup characteristics while adapting to varying wind conditions through controlled parameter changes.
Solution Approach 2:
The system implements a feedback mechanism where wind noise is continuously monitored and detected. Based on this feedback, the beamwidth parameter is automatically adjusted to optimize performance. The feedback loop ensures that the directional pattern remains stable for speech pickup while adapting to wind conditions by widening the beam when necessary.
3Object-affected harmful factors
If the beamwidth is widened to reduce wind noise sensitivity, then wind-induced noise is reduced, but speech pickup directionality deteriorates
Solution Approach 1:
The system dynamically adjusts beamwidth based on detected wind noise levels rather than using a fixed wide or narrow pattern. When wind noise is detected, the beamwidth is temporarily widened to reduce wind sensitivity; when wind conditions are calm, the beamwidth returns to a narrower configuration for optimal speech directionality. This dynamic adjustment resolves the contradiction by allowing both wide and narrow beam configurations as needed.
Solution Approach 2:
The system periodically monitors wind noise conditions and adjusts the beamwidth parameter accordingly. This periodic adjustment allows the system to switch between narrowbeam mode (for speech directionality) and widebeam mode (for wind noise reduction) based on current environmental conditions, optimizing both speech pickup and wind rejection over time.
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
In one embodiment, a directional microphone array having (at least) two microphones generates forward and backward cardioid signals from two (e.g., omnidirectional) microphone signals. An adaptation factor is applied to the backward cardioid signal, and the resulting adjusted backward cardioid signal is subtracted from the forward cardioid signal to generate a (first-order) output audio signal corresponding to a beampattern having no nulls for negative values of the adaptation factor. After low-pass filtering, spatial noise suppression can be applied to the output audio signal. Microphone arrays having one (or more) additional microphones can be designed to generate second- (or higher-) order output audio signals.