Hearing Aid Feedback Control Using Motion Data
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Solution Overview
Problem
Acoustic feedback in hearing aids causes significant performance degradation due to the microphone and loudspeaker being placed closely together, leading to howling and sound quality degradation, especially during events like yawning and chewing, which are difficult to detect and control.
Innovation Solution
A hearing aid system that incorporates motion data to adjust feedback control, utilizing a feedback control unit assisted by motion data to detect and adapt to rapid changes in the acoustic feedback path, and employs a filler signal to smooth the sound output, reducing audible artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the microphone and loudspeaker are placed closely together in a hearing aid, then the device can be made compact and wearable, but acoustic feedback occurs causing howling and sound quality degradation
Solution Approach 1:
The patent introduces a feedback control system that acts as an intermediary between the microphone and loudspeaker. This system detects the acoustic feedback path and applies adaptive filtering to cancel the feedback signal before it reaches the microphone, thereby eliminating howling while maintaining the compact placement of audio components
Solution Approach 2:
The patent implements a feedback control mechanism that continuously monitors the acoustic environment and adjusts the signal processing parameters in real-time. The system uses adaptive algorithms to track changes in the feedback path caused by user actions (yawning, chewing) and dynamically compensates for these changes, resolving the contradiction between compact design and feedback suppression
2Reliability
If the feedback control system tries to detect and respond to rapid feedback path changes (e.g., during yawning or chewing), then feedback stability can be improved, but the system may be too slow to detect these rapid changes
Solution Approach 1:
The patent employs motion sensors to detect user movements (yawning, chewing, talking) before they cause significant feedback path changes. By detecting these preliminary motions, the system can proactively adjust the feedback control parameters in advance, ensuring stable feedback suppression even during rapid transitions
Solution Approach 2:
The patent implements a dynamic feedback control system that adapts its detection and response characteristics based on the current operating conditions. The system switches between different detection modes and adjustment speeds depending on whether the user is stationary, talking, chewing, or yawning, thereby maintaining both reliability and responsiveness across all scenarios
3Object-affected harmful factors
If the hearing aid applies aggressive feedback suppression, then howling can be reduced, but audible artifacts and sound quality degradation occur
Solution Approach 1:
The patent applies feedback suppression selectively in specific frequency bands and time periods rather than uniformly across all frequencies. The system identifies which frequency bands are most prone to feedback and applies targeted suppression only to those bands, thereby eliminating howling while preserving overall sound quality and minimizing artifacts
Solution Approach 2:
The patent dynamically adjusts the feedback suppression parameters (filter coefficients, gain levels, time constants) based on the detected operating conditions and feedback characteristics. By continuously optimizing these parameters, the system achieves effective howling suppression while maintaining natural sound quality and avoiding audible artifacts
Data Source
AI summary
A hearing aid includes an input unit, an output unit, a signal processing unit connected to said input unit and output unit, where the input unit, the signal processing unit and the output unit are forming part of a forward path of the hearing aid, where the signal processing unit is configured to apply a forward gain to the at least one electric input signal or a signal originating therefrom. The hearing aid further includes a feedback control unit configured to reduce a risk of howl due to acoustic, electrical, and/or mechanical feedback of an external feedback path from the output unit to the input unit of said hearing aid, where the hearing aid is configured to receive motion data characterising movement and/or acceleration and/or orientation and/or position of the hearing aid to control processing.