Ear Mould Fitting Detection via Feedback Path Comparison
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Solution Overview
Problem
Existing listening devices, such as hearing aids, face challenges in detecting optimal ear canal coupling due to suboptimal mounting or changes in ear anatomy, particularly in children whose ears grow rapidly, leading to acoustic feedback issues like howling and the need for improved fitting verification.
Innovation Solution
A method involving a feedback estimation unit that compares long-term and current feedback path estimates to determine if an ear mould is correctly mounted, using a probe signal to assess the feedback path and provide a feedback difference measure, which indicates the fitting quality and triggers warnings or adjustments.
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 size is reduced and it can be properly mounted in the ear canal, but acoustic feedback occurs causing howling and instability
Solution Approach 1:
The patent implements a feedback cancellation system that continuously monitors the acoustic feedback path from the loudspeaker to the microphone and generates an anti-phase signal to cancel the feedback. This allows the microphone and loudspeaker to be placed closely together while preventing acoustic feedback howling through active control.
2Reliability
If the ear mould mounting is not optimal or the ear canal changes over time (especially in children), then the hearing aid becomes less effective, but detecting the optimal fitting is difficult without specialized equipment
Solution Approach 1:
The hearing aid performs self-diagnosis of its own fitting quality by analyzing the acoustic feedback characteristics. The device automatically detects changes in the feedback path that indicate improper mounting or ear canal changes, eliminating the need for external specialized equipment to assess fitting quality.
Solution Approach 2:
The system uses the acoustic feedback path as a diagnostic tool to monitor fitting quality. By analyzing changes in the feedback characteristics over time, the device can detect when the ear mould mounting becomes suboptimal or when the ear canal geometry changes, providing continuous feedback on fitting status.
Data Source
AI summary
A method detects whether an ear mold of a listening device is correctly mounted in the ear of a user. An indication of whether or not a mold of a listening device is correctly mounted in an ear canal of a user is provided. The method comprises a) providing a long term estimate of the feedback path; b) providing an estimate of the current feedback path; c) comparing the long term feedback path estimate with the current feedback path estimate, and providing a measure of their difference, termed the feedback difference measure FBDM; and optionally d) providing an alarm indication, if the feedback difference measure exceeds a predefined threshold.