Reconfigurable Fixed Beamformer Using Microphone Array Subsets
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Solution Overview
Problem
Conventional beamforming systems, particularly in audio systems, face challenges in effectively isolating desired audio while eliminating coherent noise from specific directions, especially under quiet conditions, where adaptive beamformers may distort desired signals, and struggle with complex calculations in three-dimensional environments.
Innovation Solution
The system employs a subset of microphones from a microphone array to generate target and reference signals, using directional and remote microphones to improve signal quality, and simplifies three-dimensional beamforming by reducing calculations to two-dimensional analyses, combining fixed and adaptive beamformers to enhance signal-to-noise ratio and reduce distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If adaptive beamformers are used to isolate desired audio, then noise cancellation capability is improved, but signal distortion occurs under quiet conditions
Solution Approach 1:
The system dynamically switches between fixed beamformer and adaptive beamformer based on noise conditions. A noise detector monitors the environment and controls the switch to select either the fixed beamformer (for quiet conditions) or the adaptive beamformer (for noisy conditions), preventing signal distortion while maintaining noise cancellation capability
Solution Approach 2:
The system changes the operational parameters by switching between two different beamforming modes. The fixed beamformer uses predetermined weights while the adaptive beamformer dynamically adjusts weights based on noise characteristics, allowing the system to adapt to varying acoustic environments without causing distortion
2Object-affected harmful factors
If three-dimensional beamforming is implemented to isolate audio from specific directions, then directional audio isolation is improved, but computational complexity increases
Solution Approach 1:
The three-dimensional beamforming problem is segmented into multiple two-dimensional beamforming problems. The system divides the 3D spatial environment into multiple 2D planes, performing beamforming operations on each plane separately, which reduces computational complexity while maintaining directional isolation capability
Solution Approach 2:
The system transforms the three-dimensional beamforming problem into multiple two-dimensional problems by projecting 3D spatial relationships onto 2D planes. This dimensionality reduction simplifies the computational burden while preserving the essential directional information needed for audio isolation
3Object-affected harmful factors
If all microphones in the array are used for beamforming, then audio isolation performance is improved, but processing load increases
Solution Approach 1:
The microphone array is segmented into multiple subsets, with different subsets used for different beamforming operations. This segmentation allows the system to process audio from fewer microphones at any given time, reducing processing load while maintaining isolation performance through coordinated processing of multiple subsets
Solution Approach 2:
The system uses partial action by selecting only the necessary subset of microphones for each beamforming operation rather than processing all microphones simultaneously. This selective approach reduces computational load while achieving sufficient audio isolation for the specific directional requirements
Data Source
AI summary
An acoustic interference cancellation system that performs beamforming using a subset of microphones from a microphone array. For example, a first group of microphones from an array can be used to generate target signals that focus on the direction of the desired speech in the audio and a second group of microphones from the array can be used to generate reference signals that include the environmental noise, audio from a loudspeaker, etc. The reference signals of the second group of microphones can then be used to isolate the actual speech from the target signals of the first group of microphones. The microphone array can be three dimensional, allowing a device to simplify beamforming calculations by selecting subsets of microphones along different planes. In addition, directional microphones and remote microphones may be used to improve a quality of the reference signals.