Multi-plane Microphone Array Beamforming with Covariance Matrix
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Solution Overview
Problem
Existing beamforming systems in audio systems perform poorly when isolating audio from specific azimuth directions and elevations, leading to inadequate audio boosting for tasks like automatic speech recognition (ASR) or speech-to-text processing.
Innovation Solution
A beamforming system utilizing two microphone arrays disposed on orthogonal planes with a covariance matrix to enhance audio signal processing, where the covariance matrix defines spatial relationships between microphones, allowing for better differentiation and boosting of audio from desired directions while suppressing unwanted noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single microphone array is used for beamforming, then the device complexity is low, but the audio isolation performance from specific azimuth directions and elevations is insufficient
Solution Approach 1:
The patent transitions from a single-plane microphone array to a multi-plane configuration, adding spatial dimensionality to the array structure. This enables the system to capture audio signals from multiple elevation angles simultaneously, improving audio isolation performance by creating more diverse spatial sampling points for beamforming operations.
Solution Approach 2:
The microphone array is divided into multiple independent planes, each containing its own set of microphones. This segmentation allows each plane to independently process audio signals from different spatial perspectives, and the results can be combined through beamforming to achieve superior directional audio isolation compared to a monolithic single-plane array.
2Measurement precision
If existing beamforming techniques are used, then the system is simple to operate, but the audio boosting for ASR and speech-to-text processing is inadequate
Solution Approach 1:
The patent modifies the beamforming parameters by incorporating data from multiple microphone planes, changing the spatial distribution parameters of the array. This enables more precise control over the beamforming weights and steering vectors, improving audio boosting accuracy for specific directions while maintaining systematic operation through standardized processing pipelines.
Solution Approach 2:
The patent introduces covariance matrix computation as an intermediary step between raw microphone signals and final beamformed output. This intermediary processing layer analyzes the spatial correlations between microphones across different planes, enabling more accurate estimation of signal directions and improving audio boosting precision for speech recognition applications.
Data Source
AI summary
A beamformer system isolates a desired direction of an audio signal received from a first microphone array disposed on a first plane of the system and a second microphone array disposed on a second plane of the system. A spatial covariance matrix (SCM) defines the spatial covariance between pairs of microphones. A diagonal of the SCM is varied based on the placement of the microphones; values corresponding to one microphone array are increased, and values corresponding to the other microphone array are decreased.