Directional Audio Capture with Dynamic Microphone Subband Selection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current communication devices face challenges in achieving optimal directional audio capture due to limited microphone placement and the assumption of sound propagation in a lossless medium, which restricts the frequency range and quality of beamforming, especially with microphones being too far apart, leading to aliasing effects and suboptimal audio output.
Innovation Solution
The solution involves using array signal processing with beamforming technology, dividing microphone signals into subbands, optimizing beamformer parameters independently for each frequency subband, and accounting for the shadowing effect of the device's mechanics through measurement data, allowing for the selection of the best microphone sets for each subband and switching to secondary microphones when necessary to maintain directional audio quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If microphones are placed far apart to optimize other applications (telephony, noise cancellation, video), then the device can fulfill multiple application requirements, but the distance between microphones exceeds half the wavelength of sound causing aliasing effects and limiting beamforming to low frequencies only
Solution Approach 1:
The patent segments the frequency spectrum into multiple subbands and processes each subband independently with its own beamforming parameters. This allows the system to handle different frequency ranges separately, overcoming the limitation that far-apart microphones can only form beams at low frequencies. Each subband can have optimized beamforming parameters appropriate for its frequency range.
Solution Approach 2:
The patent dynamically selects and switches between different sets of microphones based on the frequency subband being processed. For low frequency subbands, it uses the far-apart microphones optimized for telephony and noise cancellation. For high frequency subbands, it switches to nearby microphones that are suitable for beamforming, thus adapting the microphone configuration to the specific frequency requirements.
2Ease of operation
If conventional beamforming is used with far-apart microphones, then the system can capture directional audio, but the assumption of sound propagation in a lossless medium is violated due to device mechanics shadowing, reducing audio quality
Solution Approach 1:
The patent changes the beamforming parameters (weights, delays, phase shifts) independently for each frequency subband to account for the shadowing effects of device mechanics. By adapting these parameters to the actual acoustic environment at different frequencies, the system compensates for the deviations from ideal lossless medium propagation and maintains audio quality across the full frequency range.
3Measurement precision
If microphones are placed close together for optimal beamforming, then directional audio quality is improved, but the device cannot simultaneously optimize microphone positions for telephony, noise cancellation, and video applications
Solution Approach 1:
The patent makes the microphone system universal by enabling it to serve multiple functions through dynamic configuration. The same physical microphones can be selectively grouped into different sets and assigned to different frequency subbands based on the current application requirements. This allows the system to achieve optimal beamforming when needed while maintaining capability for telephony, noise cancellation, and video applications.
Solution Approach 2:
The system dynamically reconfigures which microphones are active for beamforming based on the frequency subband and application context. For high frequency subbands requiring precise beamforming, it selects nearby microphones. For low frequency subbands where telephony and noise cancellation are priorities, it uses the far-apart microphone configuration. This dynamic adaptation allows the system to optimize for different functions at different times.
Data Source
AI summary
An apparatus for providing directional audio capture may include a processor and memory storing executable computer program code that cause the apparatus to at least perform operations including assigning at least one beam direction, among a plurality of beam directions, in which to direct directionality of an output signal of one or more microphones. The computer program code may further cause the apparatus to divide microphone signals of the microphones into selected frequency subbands wherein an analysis performed. The computer program code may further cause the apparatus to select at least one set of microphones of the apparatus for selected frequency subbands. The computer program code may further cause the apparatus to optimize the assigned at least one beam direction by adjusting a beamformer parameter(s) based on the selected set of microphones and at least one of the selected frequency subbands. Corresponding methods and computer program products are also provided.