Microphone Beamforming Cross-Pattern Analysis Narrower Beams
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Solution Overview
Problem
Traditional beamforming methods suffer from performance compromises such as system size, dynamic range, noise gain, and limited sidelobe suppression, particularly due to the inflexibility of postfiltering schemes that hinder narrow beam formation.
Innovation Solution
A microphone signal beamforming processing method involving time-frequency transforming, beamforming preprocessing, cross-pattern analysis, and inverse time-frequency transforming to obtain weighted spectral components, utilizing steerable beamformers and cross-pattern analysis to enhance channel separation and achieve narrower beams with improved signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional postfiltering schemes are used for beamforming, then system complexity is reduced, but beam flexibility and narrow beam capability are limited
Solution Approach 1:
The beamforming process is divided into multiple independent frequency subbands, with each subband processed separately through its own filter bank. This segmentation allows each subband to be optimized independently, providing flexibility in beam shaping while keeping individual subband processors relatively simple.
Solution Approach 2:
The patent transforms the beamforming problem from a single-frequency approach to a multi-frequency dimension by processing signals across multiple frequency subbands simultaneously. This dimensional expansion enables complex beam patterns to be achieved through simple operations in each subband, resolving the contradiction between simplicity and flexibility.
2Object-generated harmful factors
If traditional beamforming methods are used, then sidelobe suppression is achieved, but noise gain increases and dynamic range is compromised
Solution Approach 1:
Different filter banks are designed for different frequency subbands, with each subband having optimized filter characteristics tailored to its specific frequency range. This local optimization allows sidelobe suppression to be achieved in each subband without uniformly increasing noise gain across the entire frequency spectrum.
Solution Approach 2:
The patent changes the filtering parameters dynamically across different frequency subbands, adjusting filter coefficients, orders, and characteristics to optimize the trade-off between sidelobe suppression and noise gain for each specific frequency range, rather than using fixed parameters for all frequencies.
3Ease of operation
If fixed polar patterns are used in beamforming, then implementation is simplified, but frequency independence and adaptability are reduced
Solution Approach 1:
The filter bank structure serves multiple functions simultaneously: it performs frequency decomposition, enables independent beam shaping for each subband, and provides adaptive polar pattern control. This multi-functionality allows the same basic structure to achieve both simplicity and frequency-independent adaptability.
Data Source
AI summary
A microphone signal beamforming processing method and related products are provided. The method includes: obtaining a frequency domain signal of each of at least three microphones by performing time-frequency transforming on first output signals, and performing a plurality of different groups of beamforming preprocessing on the frequency domain signals; performing a plurality of different groups of cross-pattern analysis on the plurality of beam signals to obtain a plurality of positive weighting coefficients, multiplying the plurality of positive weighting coefficients to obtain a combined coefficient, and multiplying the combined coefficient with the frequency domain signal of any one of the at least three microphones to obtain a weighted spectral component; and performing inverse time-frequency transforming on the weighted spectral component. In the disclosure, channel separation is better achieved using combined cross-pattern analysis than using traditional methods, resulting in narrower beams with excellent sidelobe suppression and higher signal-to-noise ratio.