Microphone Gain Equalization via Cross-Talk Evaluation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-microphone systems in vehicles face challenges with microphone gain mismatch, leading to unreliable speech signal enhancement and speaker zone detection due to fabrication tolerances, which affect the evaluation of room acoustics and speaker positions.
Innovation Solution
A system and method that applies automatic microphone signal gain equalization based on the evaluation of acoustic cross-talk components, using a computing unit to estimate gain factors and calculate cross-talk speech components related to existing room acoustics, without the need for direct absolute references or calibration phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microphone gain equalization is applied to compensate for fabrication tolerances, then speech signal enhancement and speaker zone detection reliability are improved, but device complexity increases due to the need for cross-talk evaluation and automatic gain calculation
Solution Approach 1:
The system performs self-calibration by automatically evaluating cross-talk components and calculating gain factors without requiring external calibration equipment or manual intervention. The microphones use the acoustic cross-talk present in the environment to self-determine their relative gain levels, making the system self-sufficient and eliminating complex external calibration procedures
Solution Approach 2:
The patent uses acoustic cross-talk as an intermediary to indirectly measure and equalize microphone gain differences. Instead of directly measuring each microphone's absolute gain (which would require complex reference equipment), the system measures the cross-talk coupling between microphones, which serves as a proxy indicator for relative gain levels, simplifying the equalization process
2Ease of operation
If cross-talk evaluation is used for gain estimation, then calibration phase and absolute reference requirements are eliminated, but measurement precision challenges arise due to the need to accurately separate cross-talk components from direct speech signals
Solution Approach 1:
The patent segments the acoustic signal into direct speech components and cross-talk components for separate analysis. By dividing the total microphone signal into these distinct parts, the system can specifically evaluate the cross-talk portion for gain estimation without being contaminated by the dominant direct speech signal, improving measurement precision
Solution Approach 2:
The patent replaces physical calibration equipment and manual adjustment mechanisms with an acoustic-based electronic evaluation system. Instead of using mechanical reference standards or physical calibration tools, the system uses acoustic cross-talk measurements and digital signal processing to automatically determine and apply gain equalization
Data Source
AI summary
Gain mismatch and related problems can be solved by a system and method that applies an automatic microphone signal gain equalization without any direct absolute reference or calibration phase. The system and method performs the steps of receiving, by a computing device, a speech signal from a speaking person via a plurality of microphones, determining a speech signal component in the time-frequency domain for each microphone of the plurality of microphones, calculating an instantaneous cross-talk coupling matrix based on the speech signal components across the microphones, estimating gain factors based on calculated cross-talk couplings and a given expected cross-talk attenuation, limiting the gain factors to appropriate maximum and minimum values, and applying the gain factors to the speech signal used in the control path to control further speech enhancement algorithms or used in the signal path for direct influence on the speech enhanced audio output signal.