Helmholtz Resonator Microphone Housing for Audio Source Tracking
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Solution Overview
Problem
Existing audio source localization systems face challenges in accurately localizing speakers in multi-person settings due to limited accuracy and noise interference, particularly with cheap microphones that have high self-noise, especially in high frequencies, which affects signal-to-noise ratio and tracking algorithms.
Innovation Solution
The proposed solution involves encapsulating microphones in a housing with a cavity and sound inlet channel to create a Helmholtz-resonator, enhancing high-frequency response and reducing self-noise, thereby improving signal-to-noise ratio and accuracy for audio source tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If microphones are placed close to the camera to enable vertical localization, then the design becomes less intrusive and more visually pleasing, but the distance between microphones decreases implying less accuracy in signal source tracking
Solution Approach 1:
The patent introduces a resonant cavity as an intermediary acoustic amplifier between the microphones and the audio signals. This cavity enhances the acoustic coupling between microphones at close distances by creating resonant pressure patterns, thereby maintaining tracking accuracy despite the reduced spacing between microphones.
Solution Approach 2:
The patent changes the acoustic parameters of the system by introducing a resonant cavity with specific volume and geometry. This modifies the acoustic impedance and pressure distribution in the region between microphones, enabling effective signal transmission over short distances while maintaining phase relationships necessary for accurate source localization.
2Ease of manufacture
If cheap microphones with high self-noise are used, then manufacturing costs are reduced, but signal-to-noise ratio deteriorates especially in high frequencies affecting tracking algorithms
Solution Approach 1:
The resonant cavity acts as an acoustic intermediary that amplifies the signal from the microphone while rejecting noise. By creating a resonant system with specific acoustic impedance, the cavity enhances the desired audio signal in the high-frequency range while the microphone's self-noise remains relatively unchanged, thereby improving the signal-to-noise ratio.
Solution Approach 2:
The patent utilizes acoustic vibration and resonance within the cavity to amplify the audio signal. The cavity is designed to resonate at specific frequencies, creating pressure patterns that enhance the acoustic signal from the microphone element, particularly in the high-frequency range where cheap microphones suffer from poor signal-to-noise ratio.
3Measurement precision
If more microphones are used to improve localization accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent merges multiple microphone functions into a compact arrangement where several microphones are positioned within a common resonant cavity structure. This combining approach allows the system to achieve high localization accuracy through multiple microphones while maintaining a compact, simple overall structure that is easy to manufacture and integrate.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design provides a significant acoustic amplification in the high-frequency range, enhancing the signal-to-noise ratio and improving the accuracy of audio source localization, allowing for more precise tracking and less intrusive camera control in video conferencing and other applications.
Implementation Method 1
encapsulating microphones in a housing with a cavity and sound inlet channel to create a Helmholtz-resonator, enhancing high-frequency response
Data Source
AI summary
An audio source tracking arrangement, integrated in or connected to a video conference system, for determining a position of a source creating a sound, including: at least an audio signal processing module configured to determine the position of the source creating the sound based on a plurality of audio signals originating from the source respectively captured by a plurality of microphones; and one or more microphone housings, respectively encapsulating at least one of the plurality of microphones, the one or more microphone housings including a cavity in which at least one of the plurality of microphones is localized, an aperture on a surface of the microphone housing, and a channel extending from the cavity to the aperture, wherein the channel and the cavity are dimensioned to form an acoustical amplifier with a frequency response having one or more high frequency peaks in a frequency band of the sound.