Microphone Array Gain Control Using Background Noise Estimation
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Solution Overview
Problem
Existing sound processing apparatuses experience delays in gain control, leading to potential signal saturation or misrecognition errors due to the time required to determine speech sections, resulting in suboptimal audio levels for speech recognition applications.
Innovation Solution
A sound processing apparatus utilizing multiple sound receiving units to estimate background noise power and compute gain control values based on this estimation and a predetermined target value, allowing for real-time gain control and reducing processing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If speech section detection is performed using conventional methods, then speech recognition accuracy is improved, but gain control delay increases
Solution Approach 1:
The patent divides the sound signal processing into two independent pathways: one for speech section detection using conventional methods (ensuring accuracy) and another for gain control using background noise power estimation (ensuring speed). This segmentation allows each pathway to optimize for its specific function without compromising the other.
Solution Approach 2:
The patent performs preliminary estimation of background noise power continuously before speech sections are detected. This preliminary action provides ready-to-use gain control values when speech is detected, eliminating the delay that would otherwise occur while waiting for speech section determination.
2Measurement precision
If sound signals are accumulated before gain control, then gain control accuracy is improved, but processing delay increases
Solution Approach 1:
The patent introduces background noise power as an intermediary parameter for gain control. Instead of directly analyzing accumulated sound signals (which causes delay), the system estimates background noise power levels and uses these estimates to determine appropriate gain control values, achieving accurate gain control without requiring signal accumulation.
3Speed
If rapid gain control is implemented, then response speed is improved, but audio level stability deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the estimated background noise power continuously informs the gain control adjustments. The system monitors noise levels and dynamically adjusts gain to maintain the audio signal at a target power level, providing both rapid response and stability through continuous feedback control.
Solution Approach 2:
The patent makes the gain control value dynamic by continuously adjusting it based on real-time background noise power estimates. Rather than using fixed or slowly-changing gain values, the system adapts gain control parameters dynamically to match current acoustic conditions, achieving both speed and stability.
Data Source
AI summary
A sound processing apparatus is provided for estimating the power of background noise using a directional sound receiving technology using a plurality of sound receiving units, computing a gain control value on the basis of the estimated power of background noise and a predetermined power target value, and outputting the gain control value, so that a delay time of starting gain control can be reduced, and a slow response of a speech recognition application program or degradation of the speech quality of a voice communication program can be prevented.