Hearing Echo Canceller with Near-End Sound Filtering
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Solution Overview
Problem
Existing hearing devices face challenges in effectively canceling acoustic echo due to noise or own voice from the near-end user, leading to poorer echo cancellation performance, especially when adaptive filters are updated using error signals that include these components.
Innovation Solution
A hearing device with processors that filter input audio signals to estimate and attenuate near-end sounds, using adaptive filters to update coefficients based on a signal where noise or own voice is minimized, thereby improving echo cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adaptive filter is updated using the error signal in traditional echo cancellation, then the echo cancellation adapts to changes in transfer function, but noise or own voice from the near-end user degrades the adaptation quality and results in poorer echo cancelling performance
Solution Approach 1:
The patent segments the error signal into two components: one containing echo information and another containing near-end speech/noise information. By separating these components, the system can update the adaptive filter using only the echo-related portion, preventing degradation from near-end interference while maintaining reliable echo cancellation performance
Solution Approach 2:
The patent extracts and removes the near-end speech and noise components from the error signal before using it for filter adaptation. This extraction process isolates the useful echo information while discarding the harmful interference, thereby improving adaptation quality without sacrificing echo cancellation reliability
2Reliability
If timing-based constraints are placed on the echo canceller adaptation to handle near-end speech, then noise degradation is reduced, but the ability to track changes in the transfer function is reduced
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the error signal for near-end speech activity and dynamically adjusts the adaptation process accordingly. When near-end speech is detected, the system modifies the update process to exclude contaminated portions, while maintaining full adaptability during clean echo-only periods, thus resolving the contradiction between stability and tracking ability
Data Source
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AI summary
A hearing device is disclosed. The hearing device comprises one or more processors, an input interface, and an output interface. The hearing device filters a first filter input signal to provide a first filtered signal, where filtering is performed to estimate an echo in a first input signal. The hearing device combines a first filtered output signal with the first input signal to provide a first output signal, the first filtered output signal is based on the first filtered signal. The hearing device filters a second filter input signal to provide a second filtered signal, where the filtering is performed to attenuate a near-end sound. The hearing device combines the second filtered output signal with the first filtered output signal to provide an update signal, where the second filtered output signal is based on the second filtered signal. The hearing device updates one or more filter coefficients based on the update signal.