Multichannel Acoustic Echo Cancellation Using Segmented Filters
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Solution Overview
Problem
Multichannel loudspeaker systems pose challenges for effective acoustic echo reduction due to the increased complexity of signal interference from multiple loudspeakers, which many existing echo reduction systems fail to adequately address.
Innovation Solution
A multichannel acoustic echo reduction system employing an acoustic echo canceller with fixed and adaptive filters, calibrated using chirps or acoustic information, and a tracker component to continuously adjust for environmental changes, combined with a beamformer and acoustic echo suppression to minimize residual echo and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple loudspeakers are used to provide multichannel audio output, then audio quality and sound coverage are improved, but acoustic echo reduction becomes more difficult and existing systems fail to adequately address the interference
Solution Approach 1:
The patent segments the echo reduction problem by creating separate adaptive filters for each loudspeaker-microphone pair. Instead of treating the multichannel system as a single complex problem, it divides the interference from multiple loudspeakers into individual components that can be processed independently, then combines the results to achieve effective echo cancellation while preserving audio quality.
2Object-affected harmful factors
If acoustic echo reduction is applied to multichannel loudspeaker systems, then echo and noise are reduced, but the system complexity increases significantly
Solution Approach 1:
The patent reduces system complexity by segmenting the echo reduction task into independent filter operations for each loudspeaker-microphone combination. This modular approach allows the complex multichannel problem to be solved through multiple simple, parallel operations rather than one complex centralized system.
Solution Approach 2:
The patent merges the individual echo reduction results from each loudspeaker-microphone pair to produce the final filtered microphone signal. By combining the outputs of multiple simple filters rather than using one complex filter, the system achieves effective echo cancellation with manageable complexity.
3Measurement precision
If fixed filters are calibrated for each loudspeaker-microphone combination, then echo estimation accuracy is improved, but calibration time and processing overhead increase
Solution Approach 1:
The patent performs calibration of fixed filters for each loudspeaker-microphone combination in advance, before actual voice communication begins. This preliminary action ensures that echo estimation is already optimized when needed, without adding delay to the actual communication process.
Solution Approach 2:
The patent employs adaptive filters that can dynamically adjust the fixed filter parameters in real-time based on changing acoustic conditions. This allows the system to maintain high echo estimation accuracy even when environmental conditions change, without requiring complete recalibration.
Data Source
AI summary
A multichannel acoustic echo reduction system is described herein. The system includes an acoustic echo canceller (AEC) component having a fixed filter for each respective combination of loudspeaker and microphone signals and having an adaptive filter for each microphone signal. For each microphone signal, the AEC component modifies the microphone signal to reduce contributions from the outputs of the loudspeakers based at least in part on the respective adaptive filter associated with the microphone signal and the set of fixed filters associated with the respective microphone signal.