Multi-Microphone Array Noise Reduction via Frequency Sub-Band Segmentation
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Solution Overview
Problem
Current multi-microphone array technologies are ineffective in inhibiting broad-band noises and are not suitable for widespread broad-band communication, as they require a large number of microphones and a significant microphone array size, making them unsuitable for small devices like cameras and TVs.
Innovation Solution
The method involves dividing the full frequency band into sub-bands based on the number of spacings between microphones, decomposing signals into corresponding sub-bands, and using adaptive filters to reduce noise in each sub-band, then synthesizing the noise-reduced signals to achieve effective broad-band noise reduction with a smaller microphone array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If constant beamwidth beamforming technology is used to inhibit broad-band noises, then noise reduction effect is improved, but the number of microphones and array size increase significantly
Solution Approach 1:
The patent divides the full frequency band into multiple sub-bands (e.g., low-frequency band, mid-frequency band, high-frequency band) and applies different beamforming technologies to each sub-band. This segmentation allows the system to use a smaller number of microphones while achieving effective noise reduction across the entire frequency spectrum, as each sub-band can be processed with optimized parameters rather than requiring a comprehensive array for the entire band.
Solution Approach 2:
The patent applies different beamforming methods to different frequency sub-bands based on their specific characteristics. For example, narrow-band beamforming is used for certain sub-bands while constant beamwidth beamforming is applied to others. This local optimization allows each sub-band to receive the appropriate processing technique, improving overall noise reduction effectiveness without requiring a uniformly large microphone array across all frequencies.
2Object-affected harmful factors
If narrow-band beamforming technology is used, then noise reduction is achieved for specific frequency bands, but it cannot effectively inhibit broad-band noises
Solution Approach 1:
The patent segments the frequency spectrum into multiple sub-bands and applies appropriate beamforming techniques to each. This allows the system to maintain the effectiveness of narrow-band beamforming for specific frequency ranges while extending its capability to handle broad-band noises through the combined processing of multiple sub-bands, thereby improving adaptability to various noise types and communication scenarios.
Solution Approach 2:
The patent creates a multi-functional noise reduction system that can handle both narrow-band and broad-band noises by combining different beamforming technologies. The system universally applies to various communication scenarios (e.g., video conferencing, telephony) by adapting its processing based on the detected noise characteristics and frequency band, making it versatile for broad-band communication applications.
Data Source
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AI summary
To solve the problems with the prior art that a multi-microphone array cannot inhibit broad-band noises well and cannot be used in the increasingly widespread broad-band communication, embodiments of the present invention disclose a method, a device and a system for eliminating noises with multi-microphone array. The method according to an embodiment of the present invention comprises according to the number of different spacings between each of pairs of microphones of the multi-microphone array, dividing a full frequency band into the same number of sub-bands; decomposing signals of each of the pairs of microphones with the different spacings into a corresponding one of the sub-bands, wherein the larger the spacing between each pair of microphones is, the lower the frequencies of the sub-band into which the signals of the pair of microphones are decomposed will be; adaptively reducing the noises in the decomposed signals of each of the pairs of microphones with the different spacings in the corresponding sub-band to obtain noise-reduced signals for each of the sub-bands; and synthesizing the noise-reduced signals of each of the sub-bands to obtain a signal in which the noises have been reduced with the multi-microphone array in the full frequency band. The embodiments of the present invention can be used in scenarios of hands-free video calls.