Post-Mixing Acoustic Echo Cancellation Using Shared Filters
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Solution Overview
Problem
Existing acoustic echo cancellation systems are computationally intensive and complex, particularly when dealing with dynamic mixers and multiple microphones, leading to inefficiencies and increased resource requirements.
Innovation Solution
The proposed system generates an echo-cancelled mixed audio signal by selecting tap coefficients of background, hidden, and mix filters based on error power comparisons, and uses a non-linear processor to further suppress echoes when the filters have not converged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate echo cancellers are used for each microphone, then echo cancellation effectiveness is improved, but computational complexity and system resource requirements increase
Solution Approach 1:
The patent combines multiple separate echo cancellers into a single shared echo canceller that processes the mixed audio signal from all microphones simultaneously. This merging approach maintains effective echo cancellation while significantly reducing computational complexity and system resource requirements, directly resolving the technical contradiction between cancellation effectiveness and system complexity.
Solution Approach 2:
The shared echo canceller performs multiple functions by processing the combined audio signal from all microphones, effectively handling echo cancellation for the entire conference room environment. This universal approach eliminates the need for separate dedicated processing channels for each microphone, reducing overall system complexity while maintaining comprehensive echo suppression.
2Reliability
If separate echo cancellers are used for each microphone, then echo cancellation effectiveness is improved, but computational resources and processing power requirements increase
Solution Approach 1:
The patent merges multiple separate echo cancellation processing channels into a single shared processing channel that handles the mixed audio signal. This consolidation dramatically reduces the computational resources required, as the system performs one echo cancellation operation on the combined signal rather than multiple separate operations, directly addressing the contradiction between cancellation effectiveness and computational resource consumption.
3Reliability
If a typical acoustic echo canceller is placed after a mixer, then echo cancellation can be performed, but the system becomes unstable when the mixer is dynamic with changing gains
Solution Approach 1:
The patent performs echo cancellation on the mixed audio signal before the mixer applies its dynamic gain adjustments. By preliminarily processing the echo cancellation on the pre-mix signal, the system avoids the instability that would result from attempting to adapt to continuously changing mixer gains, thereby maintaining system stability while preserving echo cancellation capability.
Data Source
AI summary
Acoustic echo cancellation systems and methods are provided that can cancel and suppress acoustic echo from the output of a mixer that has mixed audio signals from a plurality of acoustic sources, such as microphones. The microphones may have captured speech and sound from a remote location or far end, such as in a conferencing environment. The acoustic echo cancellation may generate an echo-cancelled mixed audio signal based on a mixed audio signal from a mixer, information gathered from the audio signal from each of the plurality of acoustic sources, and a remote audio signal. The systems and methods may be computationally efficient and resource-friendly.