Microphone Gain Control Using 3D Source Position and Path Loss
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Solution Overview
Problem
Current automatic gain control systems in audio conferencing fail to provide consistent performance due to unknown sound source and ambient noise levels, leading to inconsistent volume and user experience, as they rely on heuristic methods without knowing the position of sound sources.
Innovation Solution
A method utilizing positional 3D spatial sound power information to calculate and control individual microphone gains based on known path loss calculations, allowing for deterministic gain adjustments and maintaining consistent ambient sound levels by focusing on sound source location rather than overall signal strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heuristic-based automatic gain control is used to manage wide dynamic range audio signals, then audio conferencing system performance is enhanced, but the ambient sound levels track in proportion to volume changes causing inconsistent sound levels
Solution Approach 1:
The patent segments the audio processing into two independent gain control channels: one for the desired sound source signal and another for ambient sound. The system calculates separate gain values - a first gain value for the sound source based on its position and path loss, and a second gain value for ambient sound. This segmentation allows independent control of each component, preventing the coupling effect where ambient sound levels track with volume changes.
Solution Approach 2:
The patent applies different gain control strategies to different audio components based on their local characteristics. The sound source gain is determined by positional information and path loss calculations, while the ambient sound gain is controlled separately to maintain consistency. This local quality approach allows each audio component to be optimized independently according to its specific requirements.
2Device complexity
If automatic gain control operates on heuristic principles without knowing sound source position, then the system can function without additional sensors, but the performance is not deterministic and shows hunting behavior
Solution Approach 1:
The patent introduces feedback by using the output of the sound source position determination and path loss calculation to dynamically adjust the gain value. The system continuously monitors the sound source position, calculates the corresponding path loss, and feeds this information back to the gain control mechanism. This closed-loop feedback ensures deterministic performance by basing gain adjustments on actual measured positional data rather than heuristic assumptions.
Solution Approach 2:
The patent replaces the mechanical/heuristic gain adjustment system with an information-based system that uses positional data and path loss calculations. Instead of relying on heuristic principles and assumptions about sound source location, the system substitutes a computational approach that calculates gain based on measured position and known acoustic propagation characteristics, eliminating the hunting behavior associated with heuristic methods.
3Adaptability or versatility
If gain is adjusted to normalize to preset parameters, then the system can handle variable signal levels, but the preset parameters may not be suitable to the actual situation causing inconsistent volume
Solution Approach 1:
The patent transforms the static preset parameter approach into a dynamic system that adapts gain values in real-time based on sound source position. Instead of using fixed normalization parameters that may not suit actual situations, the system continuously updates the gain calculation based on the current sound source location and path loss. This dynamic adaptation ensures both versatility in handling variable signal levels and precision in maintaining consistent volume appropriate to the actual acoustic situation.
Data Source
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AI summary
Method and apparatus for automatic gain control utilizing sound source position information in a shared space having a plurality of microphones and a plurality of sound sources. Sound signals are received from the microphones. One or more processors locate position information corresponding to each of the sound sources. The processor(s) determine the distance to each of the sound sources from each of the microphones. The processor(s) define a predetermined gain weight adjustment for each of the microphones. The processor(s) apply the defined weight adjustments to the microphones to achieve a consistent volume of the desired plurality of sound sources. The processor(s) maintain a consistent ambient sound level regardless of the position of the sound sources and the applied gain weight adjustments. The processor(s) output a summed signal of the sound sources at a consistent volume with a constant ambient sound level across the plurality of sound source positions.