Microphone Placement for Wind Noise Reduction
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Solution Overview
Problem
Existing audio systems in image capture devices face challenges in reducing wind noise, particularly when protruding features on the device cause turbulence, affecting microphone performance during physical activities and varying environmental conditions.
Innovation Solution
The implementation of a microphone drainage system with strategically positioned microphones and an audio processor that generates and combines frequency sub-band signals to minimize wind noise by selecting the sub-band signals with the lowest noise metric, optimizing microphone placement to receive direct freestream and turbulent air flows at specific angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single microphone is mounted near protruding features, then the device structure is simple, but wind noise increases due to turbulence
Solution Approach 1:
The audio capture function is segmented across multiple microphones positioned at different locations on the device housing. Each microphone captures audio from different airflow conditions, and the audio processor segments the audio spectrum into frequency sub-bands to selectively combine signals with lowest noise metrics.
Solution Approach 2:
Different microphones are positioned to experience different local airflow conditions - some receive direct freestream flow while others receive turbulent flow near protruding features. The audio processor selects signals based on local noise characteristics at each microphone position and frequency sub-band.
2Object-affected harmful factors
If microphones are positioned to receive direct freestream air flow, then wind noise is reduced, but audio capture is limited at certain device orientations
Solution Approach 1:
Multiple microphones serve multiple functions depending on device orientation - some microphones that capture wind noise at certain angles capture clean audio at other angles. The system universally adapts to different orientations by selecting the best available signal from any microphone at each frequency sub-band.
Solution Approach 2:
The system dynamically selects which microphone signals to use based on real-time conditions including device orientation and airflow patterns. The audio processor adapts the combination of microphone signals dynamically rather than using a fixed configuration.
3Object-affected harmful factors
If multiple microphones are strategically positioned, then wind noise is reduced through signal selection, but device complexity increases
Solution Approach 1:
Instead of using complex mechanical wind shields or positioning mechanisms to protect microphones, the patent substitutes a computational approach where the audio processor analyzes and combines signals from multiple microphones to electronically eliminate wind noise based on noise metric calculations.
Data Source
AI summary
An image capture device, having: a housing, a lens snout, a front microphone, a top microphone, and an audio processor. The housing has a top and front housing surface. The lens snout protrudes from the front housing surface. The front microphone mounted within or on the front housing surface and below the lens snout. The top microphone mounted within or on a top housing surface in a position biased toward the front housing surface. The audio processor comprises a memory that is configured to store instructions that when executed cause the audio processor to generate an output audio signal. The top microphone is located at a position to receive direct freestream air flow when the housing is positioned in a pitched forward orientation at a pitched forward angle relative to a vertical axis. The front microphone receives turbulent air flow from the lens snout when the housing is positioned in the pitched forward orientation.