UAV Microphone Wind Noise Suppression via Segmentation
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Solution Overview
Problem
Unmanned air vehicles face challenges in properly sensing ambient sounds due to wind noise generated by propellers, which interferes with noise cancellation techniques, making it difficult to distinguish and remove propeller noise from ambient sounds.
Innovation Solution
The unmanned air vehicle is equipped with multiple generators, first microphones located outside airflow regions, and second microphones positioned between generators and first microphones, along with a processor that processes signals from both to suppress wind noise and accurately sense noise generated by the propellers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the microphone is disposed close to the propeller to properly detect propeller noise, then the noise detection accuracy is improved, but wind noise is generated by the propeller airflow hitting the microphone which degrades the detection accuracy
Solution Approach 1:
The patent divides the microphone system into two separate microphones: a first microphone positioned away from the propeller to capture ambient sound without wind noise, and a second microphone positioned close to the propeller to capture propeller noise. This segmentation allows each microphone to perform its specific function optimally without interference from wind noise.
Solution Approach 2:
The patent introduces a wind noise estimation mechanism that uses the signal from the first microphone (which captures ambient sound without propeller interference) as an intermediary to estimate and subtract wind noise components from the signal captured by the second microphone. This intermediary approach enables accurate propeller noise detection by separating it from wind noise through mathematical processing.
2Reliability
If the microphone is disposed close to the propeller to capture propeller noise, then the noise cancellation effectiveness is improved, but the wind noise from propeller airflow degrades the signal quality
Solution Approach 1:
The patent segments the sound capture function into two dedicated microphones: one for ambient sound capture (first microphone) and one for propeller noise capture (second microphone). This segmentation ensures that the second microphone can be positioned optimally close to the propeller for effective noise cancellation without compromising signal quality, as the wind noise affecting it can be estimated and removed using the first microphone's clean ambient sound signal.
Solution Approach 2:
The patent implements a feedback mechanism where the signal from the first microphone is used to estimate wind noise components, which are then subtracted from the second microphone's signal to produce a cleaned propeller noise signal. This feedback loop continuously refines the noise estimation and removal process, maintaining high signal quality for effective noise cancellation.
3Object-affected harmful factors
If the microphone is positioned away from the propeller to avoid wind noise, then wind noise input is reduced, but the ability to detect and remove propeller noise from ambient sounds is degraded
Solution Approach 1:
The patent resolves this contradiction by segmenting the measurement function across two microphones: the first microphone is positioned away from the propeller to avoid wind noise and capture clean ambient sound, while the second microphone is positioned close to the propeller to capture propeller noise directly. This segmentation allows both objectives to be achieved simultaneously through coordinated signal processing.
Solution Approach 2:
The first microphone's clean ambient sound signal serves as an intermediary reference that enables the system to estimate and remove wind noise components from the second microphone's signal. This intermediary approach allows accurate propeller noise detection and removal even though the first microphone itself does not capture propeller noise directly.
Data Source
AI summary
An unmanned air vehicle is provided. The unmanned air vehicle includes one or more generators, each of which generates a force that drives the unmanned air vehicle to fly and also generates an airflow. Each of one or more first microphones is located in an external region that is not included in any of one or more first airflow regions. Each of the one or more first airflow regions corresponds to the airflow generated by one of the one or more generators. Each of one or more second microphones is located in the external region between at least one of the one or more generators and the one or more first microphones. A processor performs processing on one or more first signals output from the one or more first microphones and one or more second signals output from the one or more second microphones.