Adaptive Microphone Array Beamforming for Compact Noise Suppression
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Solution Overview
Problem
Conventional microphone arrays are unsuitable for hands-free or handheld speech acquisition devices due to their large and bulky size, which is required to effectively handle broadband speech applications with wide bandwidth signals, and they fail to suppress ambient noise effectively.
Innovation Solution
A microphone array system comprising an array of sound sensors in an arbitrary configuration, a sound source localization unit, an adaptive beamforming unit, and a noise reduction unit, which estimates the spatial location of the target sound signal and steers the directivity pattern to enhance the target sound while suppressing ambient noise using adaptive beamforming and noise reduction algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional microphone arrays are used to handle broadband speech applications, then the bandwidth coverage is improved, but the device size becomes large and bulky
Solution Approach 1:
The patent divides the broadband speech signal processing into multiple narrowband frequency bands. Each band is processed independently by separate beamforming channels, allowing the use of smaller sensor spacing while maintaining effective broadband coverage. This segmentation enables compact device design without sacrificing bandwidth adaptability.
Solution Approach 2:
The patent transitions from spatial domain processing to frequency domain processing by applying Fast Fourier Transform (FFT) to divide the broadband signal into multiple frequency bins. This dimensional transformation allows independent optimization of each frequency band, enabling compact array design that would be impossible with conventional broadband approaches requiring large physical apertures.
2Measurement precision
If conventional microphone arrays are used, then directional gain can be achieved, but the device becomes unsuitable for hands-free or handheld applications
Solution Approach 1:
By segmenting the broadband signal into narrowband frequency components, the patent enables effective directional beamforming at each frequency bin with reduced sensor spacing. This allows the array to maintain portability for handheld devices while achieving precise directional gain through frequency-specific beamforming operations.
Solution Approach 2:
The patent dynamically adjusts beamforming parameters (weights, delays, phases) for each frequency band based on the estimated direction of arrival. This parameter optimization across multiple frequency dimensions enables high directional gain in compact configurations suitable for portable devices.
3Device complexity
If a single microphone is used, then the device remains simple and compact, but ambient noise suppression capability deteriorates
Solution Approach 1:
The patent applies segmentation to both spatial and frequency domains, creating multiple processing channels that independently analyze different frequency bands. This segmented approach enables sophisticated noise suppression through comparative analysis across channels while maintaining relatively simple individual channel processing, achieving effective noise rejection without excessive overall complexity.
Solution Approach 2:
The patent implements adaptive feedback mechanisms where the system continuously estimates the direction of arrival of desired speech signals and adjusts beamforming weights accordingly. This feedback loop enables dynamic suppression of ambient noise from directions other than the estimated speech source, significantly improving noise rejection capability.
Data Source
AI summary
A method and system for enhancing a target sound signal from multiple sound signals is provided. An array of an arbitrary number of sound sensors positioned in an arbitrary configuration receives the sound signals from multiple disparate sources. The sound signals comprise the target sound signal from a target sound source, and ambient noise signals. A sound source localization unit, an adaptive beamforming unit, and a noise reduction unit are in operative communication with the array of sound sensors. The sound source localization unit estimates a spatial location of the target sound signal from the received sound signals. The adaptive beamforming unit performs adaptive beamforming by steering a directivity pattern of the array of sound sensors in a direction of the spatial location of the target sound signal, thereby enhancing the target sound signal and partially suppressing the ambient noise signals, which are further suppressed by the noise reduction unit.