Microphone Array Noise Reduction via Incidence Angle Adaptive Filtering
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Solution Overview
Problem
Existing speech enhancement technologies using microphone arrays struggle to accurately suppress non-steady noise and maintain speech quality, especially in low SNR environments, as they often damage speech while reducing noise due to inadequate control of adaptive filters and strict microphone consistency requirements.
Innovation Solution
The method involves determining incidence angles of acoustic signals using a microphone array, conducting statistical analysis to calculate a control parameter α, and using this parameter to control the adaptive filter's update rate, allowing for precise noise reduction without damaging speech. This approach eliminates the need for energy information and reduces strict microphone consistency requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If adaptive filter is used to counteract noise in microphone array, then noise suppression is improved, but speech quality deteriorates due to speech being counteracted along with noise
Solution Approach 1:
The patent applies local quality by making the adaptive filter's update rate spatially selective based on incidence angle. Different regions of the signal space receive different filtering treatments: signals from directions where speech is likely present use a slower update rate to protect speech, while signals from noise-dominated directions use a faster update rate for effective noise suppression. This resolves the contradiction by applying noise suppression locally where it benefits speech quality rather than uniformly across all signals.
Solution Approach 2:
The patent implements dynamics by making the adaptive filter's update rate adjustable and time-varying based on the detected incidence angle of incoming signals. The update rate transitions between slow and fast modes dynamically according to whether the signal direction corresponds to speech or noise sources. This dynamic adaptation allows the system to optimize between noise suppression and speech preservation in real-time, resolving the static contradiction between these two opposing goals.
2Object-affected harmful factors
If directive microphone is used to determine signal directions by comparing energy differences, then noise elimination is improved, but microphone consistency requirements increase and speech state determination accuracy decreases in high noise environments
Solution Approach 1:
The patent introduces an intermediary approach by using incidence angle detection as a mediator between raw signal energy and noise elimination control. Instead of directly using energy differences from directive microphones (which are sensitive to consistency errors), the system detects the angle of incoming signals and uses this angular information to control the adaptive filter. This intermediary measurement is more robust to microphone inconsistencies and provides more reliable speech state determination even in high noise environments.
3Object-affected harmful factors
If single microphone spectral subtraction is used, then steady-state noise suppression is achieved, but non-steady noise suppression fails and speech is damaged in low SNR conditions
Solution Approach 1:
The patent applies dynamics by enabling the noise suppression system to adapt its behavior based on the temporal characteristics of the noise and the detected signal direction. The incidence angle information allows the system to dynamically adjust whether to apply aggressive noise suppression or to prioritize speech preservation, making it effective for both steady-state and non-steady noise conditions. This resolves the contradiction by making the system versatile across different noise types rather than limited to steady-state only.
Data Source
AI summary
The present invention provides a noise reduction control method using a microphone array and a noise reduction control device using a microphone array wherein the method comprises the steps of: S1: collecting, by the microphone array, acoustic signals; S2: estimating incidence angles of all acoustic signals of the microphone array; S3: conducting a statistics on signal components according to incidence angles; S4: determining a parameter α from a ratio of noise components according to the statistical result and using the parameter α as a control parameter for controlling an adaptive filter. With the present invention, space position information of the sound is obtained directly with the microphone array to control update of the adaptive filter more accurately, so as to eliminate noise, enhance SNR and protect speech quality well at the same time.