Adaptive Echo Suppressor for Multi-Channel Audio Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional echo cancellation systems in audio systems face instability and echo leakage due to inaccurate echo prediction, especially in multi-channel outputs with unexpected system changes and nonlinearities, leading to significant echo leaks in real-time communication systems.
Innovation Solution
The proposed solution involves an adaptive echo suppressor that modifies echo suppression behavior independently of the echo cancellation system, forcing higher suppression and adaptation rates in response to detected echo power or system events, and using predicted echo power values and worst-case filter coefficients to enhance echo suppression, particularly in scenarios with non-full rank covariance matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional echo cancellation is used in multi-channel audio systems, then echo suppression is provided, but echo leakage occurs due to inaccurate echo prediction and system instability
Solution Approach 1:
The system dynamically adjusts the adaptation rate of the echo suppressor based on detected conditions. When rendering changes are detected or echo power exceeds thresholds, the adaptation rate is increased to quickly respond to inaccurate echo prediction. This dynamic adjustment allows the system to maintain stability during normal operation while rapidly adapting when echo leakage occurs.
Solution Approach 2:
The system implements feedback mechanisms by monitoring residual echo power and comparing it against thresholds. When echo power exceeds the threshold or rendering changes are detected, the system triggers modified echo suppression with forced adaptation. This feedback loop ensures the system responds to actual echo leakage conditions and adjusts suppression levels accordingly.
Solution Approach 3:
The system changes key parameters including adaptation rate, echo power thresholds, and suppression levels based on operating conditions. By scaling the predicted echo power value and adjusting the adaptation rate dynamically, the system adapts to different acoustic environments and rendering configurations, resolving the contradiction between suppression effectiveness and stability.
2Object-generated harmful factors
If echo suppression is increased to reduce echo leakage, then echo cancellation performance improves, but desired signal may be misclassified and suppressed
Solution Approach 1:
The system applies partial suppression by targeting only pre-selected frequency bands where echo is most prominent, rather than suppressing all frequencies. The modification forces adaptation and increases suppression selectively based on detected echo power levels, applying excessive suppression only when and where needed to reduce echo leakage without unnecessarily suppressing desired speech signals.
Solution Approach 2:
The system replaces conventional echo cancellation mechanisms with an adaptive echo suppressor that operates independently. This suppressor uses predicted echo power values and adaptation rate control to distinguish between echo and desired signal, substituting the traditional mechanical echo cancellation approach with a more flexible adaptive system that reduces misclassification.
3Speed
If adaptation rate is increased to respond to rendering changes, then echo suppression responsiveness improves, but system instability increases
Solution Approach 1:
The system uses periodic monitoring of rendering changes and echo power levels to trigger adaptation rate adjustments. Rather than continuously adjusting at maximum rate, the system periodically checks for conditions (rendering changes, echo power thresholds) and only increases adaptation rate when needed, maintaining stability during normal operation while responding quickly to actual changes.
Solution Approach 2:
The system prepares for potential instability by using conservative adaptation rates during normal operation and only increasing the rate when rendering changes are detected or echo leakage is confirmed. This beforehand cushioning approach prevents unnecessary rapid adaptation that could cause instability while ensuring quick response when actually needed.
Data Source
AI summary
Systems and methods are described for compensating for inaccurate echo prediction in audio systems. A signal may be received at a microphone of an audio system, the signal including audio rendered using a spatial audio renderer across a multi-channel audio output. A signal may be received from the spatial audio renderer that indicates a change in rendering of audio. The audio system may then determine if there is echo power within the received signal greater than an expected echo power. After the signal from the spatial audio renderer has been received, the echo suppression applied to the received signal may be modified in response to a determination that the echo power is greater than the expected echo power, the echo suppression attenuating pre-selected frequency bands of the received signal.