Sound Field Spatial Stabilizer for Microphone Arrays
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Solution Overview
Problem
Stereo and multichannel microphone configurations often lose spatial information due to noise suppression processes, resulting in a single, mono output signal that lacks spatial stability.
Innovation Solution
A system and method that calculates balance gains for each microphone signal to maintain spatial stability by adjusting and mixing signals, using echo cancellation, noise reduction, and background noise estimation techniques to mitigate distortions and preserve spatial information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise suppression processes are applied to improve noise performance, then noise is reduced, but spatial information is lost
Solution Approach 1:
The patent applies different processing characteristics to different frequency components and spatial channels. By treating each spatial channel independently and applying frequency-dependent gain adjustments, the system preserves spatial information locally while suppressing noise, rather than applying uniform noise suppression that would destroy spatial cues.
Solution Approach 2:
The system dynamically adjusts signal parameters (gains, spatial coordinates) based on the estimated sound field characteristics. By changing parameters adaptively rather than using fixed noise suppression, the system maintains spatial stability while reducing noise, resolving the contradiction between noise reduction and spatial information preservation.
2Object-affected harmful factors
If multiple microphone signals are processed to improve noise performance, then noise suppression is enhanced, but spatial stability deteriorates
Solution Approach 1:
The system uses feedback from spatial coherence measurements and sound field estimation to continuously adjust processing parameters. This feedback mechanism ensures that noise suppression operations maintain spatial stability by adapting to the actual spatial characteristics of the sound field rather than applying fixed transformations.
Solution Approach 2:
The patent implements dynamic spatial processing where gain factors and spatial parameters are continuously updated based on real-time sound field analysis. This dynamic approach allows the system to maintain spatial stability under varying noise conditions, unlike static processing that would compromise spatial consistency.
3Object-affected harmful factors
If signal gains are adjusted to improve noise suppression, then noise reduction is improved, but audible distortions increase
Solution Approach 1:
The system applies partial noise suppression by selectively attenuating only the noise components rather than aggressively suppressing all signals. By using moderate, frequency-selective gain adjustments rather than extreme suppression, the system reduces noise while minimizing audible distortions that would result from excessive processing.
Data Source
AI summary
In a system and method for maintaining the spatial stability of a sound field a balance gain may be calculated for two or more microphone signals. The balance gain may be associated with a spatial image in the sound field. Signal values may be calculated for each of the microphone. The signal values may be signal estimates or signal gains calculated to improve a characteristic of the microphone signals. The differences between the signal values associated with each microphone signal may be limited although some difference between signal values may be allowable. One or more microphone signals are adjusted responsive to the two or more balance gains and the signal gains to maintain the spatial stability of the sound field. The adjustments of one or more microphone signals may include mixing of two or more microphone. The signal gains are applied to the two or more microphone signals.