LISTENING DEVICE AND A METHOD OF MONITORING THE FITTING OF AN EAR MOULD OF A LISTENING DEVICE

• US 20130170660A1
• Filed: 01/02/2013
• Published: 07/04/2013
• Est. Priority Date: 01/03/2012
• Status: Active Grant

• Current Assignee: Oticon A/S (William Demant Fonden)
• Original Assignee: Oticon A/S (William Demant Fonden)
• Inventors: PEDERSEN, Michael Syskind, KAULBERG, Thomas, KRISTENSEN, Michael Smed
• Granted Patent: US 10,306,374 B2
• Time in Patent Office: Days
• US Class Current: 381/60
• CPC Class Codes: H04R 2460/15 Determination of the acoustic seal of ear moulds or ear tips of hearing devices
• CPC Class Codes: H04R 25/30 Monitoring or testing of hearing aids, e.g. functioning, settings, battery power
• CPC Class Codes: H04R 25/305 Self-monitoring or self-testing
• CPC Class Codes: H04R 25/453 electronically
• CPC Class Codes: H04R 25/554 using a wireless connection, e.g. between microphone and amplifier or using Tcoils
• CPC Class Codes: H04R 25/558 Remote control, e.g. of amplification, frequency

Abstract

A method detects whether an ear mould of a listening device is correctly mounted in the ear of a user. An indication of whether or not a mould 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.

Claims

1. A method of detecting whether an ear mould of a listening device is correctly mounted in the ear of a user, the listening device comprising

a forward path between an input transducer for converting an input sound to an electric input signal and an output transducer for converting an electric output signal to a stimulus perceived by the user as an output sound, the forward path comprising a signal processing unit for applying a frequency dependent gain to the electric input signal or a signal originating therefrom and for providing a processed signal, and feeding the processed signal or a signal originating therefrom to the output transducer;

an analysis path for analysing a signal of the forward path and comprising a feedback estimation unit for estimating a feedback path from the output transducer to the input transducer,

the method comprising

a) providing a long term estimate of the feedback path;

b) providing a probe signal, which can be relayed to the environment of the listening device by the output transducer;

b) providing an estimate of the current feedback path based on said probe signal;

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.

2. A method according to claim 1 comprising:

providing the long term estimate of the feedback path and/or the current feedback path at a number NI of feedback calculation frequencies f₁, f₂, . . . , f_NI.

3. A method according to claim 2 wherein the feedback difference measure depends on the difference between the long term feedback path estimate and the current feedback path estimate determined at a number of frequencies comprising at least some of said feedback calculation frequencies f₁, f₂, . . . , f_NI.

4. A method according to claim 1, wherein the long term feedback path estimate and/or the current feedback path estimate is/are based on an adaptive algorithm of the feedback estimation unit.

5. A method according to claim 1, wherein the current feedback path estimate is based on an open loop estimation where the probe signal is played by a loudspeaker of the listening device.

6. A method according to claim 1 wherein the probe signal comprises one or more tones located at one or more predefined frequencies f₁, f₂, . . . , f_NT.

7. A method according to claim 2 wherein the probe signal comprises one or more tones located at one or more of said feedback calculation frequencies f₁, f₂, . . . , f_NI, where the current feedback path is estimated.

8. A method according to claim 1 wherein the probe signal comprises a number of tones located at the frequencies exhibiting the largest long term feedback path estimates.

9. A method according to claim 1 wherein the probe signal comprises one or more tones, the level and/or duration of the tones and/or order in which the tones are played when activating the probe signal depend(s) on the level of the input signal of the frequency channel(s) wherein the probe signal tone(s) in question is/are located.

10. A method according to claim 6 wherein a first selected tone of frequency f₁ is played at a first time t₁, and a second selected tone of frequency f₂ is played at a second time t₂., and wherein the time interval (Δ

t=t₂−

t₁) between the playing of the first and second tones is sufficiently long to ensure that the feedback path estimate at the first frequency f₁ has converged, and wherein a first, relatively large adaptation rate AR₁ of the adaptive algorithm of the feedback path estimate is used during an initial, first part of the time interval Δ

t and a second relatively smaller adaptation rate AR₂ is used during a second part of the time interval Δ

t.

11. A method according to claim 1, wherein the probe signal comprises the electric input signal picked up by the input transducer of the listening device.

12. A method according to claim 11, wherein the electric input signal comprises a wirelessly received signal from an auxiliary device.

13. A method according to claim 1 wherein the probe signal is applied in a particular mode of the listening device, e.g. as part of a start-up procedure, or at the request of a user, e.g. initiated via a user interface, e.g. a remote control.

14. A method according to claim 1, wherein the current and/or long term feedback path estimate is based on a closed loop estimation based on external sounds and/or internally generated probe signals.

15. A method according to claim 1, wherein the long term feedback path estimate is determined based on values of the current feedback path estimate stored in a memory of the listening device.

16. A method according to claim 1 comprising the step of providing an alarm indication, if the feedback difference measure fulfils a predefined criterion, e.g. exceeds a predefined threshold.

17. A method according to claim 11 wherein an initial indication of the fitting of an ear mould during a first time fitting of the ear mould in question to a user is provided.

18. A method according to claim 17, wherein an initial long term feedback estimate or IG_max,LT is stored in the listening device, and a current feedback estimate based on the probe signal is compared with the initial long term estimate, whereby—

when an audiologist or other skilled person has ensured that the ear mould is correctly mounted in the ear of the user—

a conclusion concerning the quality of the fitting of the ear mould can be drawn.

19. A method according to claim 1, wherein the initial long term estimate is based on a user'"'"'s hearing profile, including a maximum prescribed gain IG_max(f) in a quiet environment including a possible volume gain applied by the user at a number of frequencies distributed over the frequency range of operation of the listening device.

23. A data processing system comprising a processor and program code means for causing the processor to perform the steps of the method of claim 1.

20. A listening device comprising an ear mould adapted for being mounted in the ear of a user, the listening device comprising

a forward path between an input transducer converting an input sound to an electric input signal and an output transducer for converting an electric output signal to an output sound, the forward path comprising a signal processing unit for applying a frequency dependent gain to the electric input signal or a signal originating therefrom and for providing a processed signal, and feeding the processed signal or a signal originating therefrom to the output transducer;

an analysis path for analysing a signal of the forward path and comprising a feedback estimation unit for estimating a feedback path from the output transducer to the input transducer,

the listening device further comprising

a probe signal generator for generating a probe signal and adapted to allow a relay of the probe signal to the environment of the listening device by the output transducer;

a feedback management unit for

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 for their difference.

21. A listening device according to claim 20 comprising an alarm indication unit for providing an alarm indication, if the feedback difference measure exceeds a predefined threshold.

22. A listening device according to claim 21 adapted to provide that the alarm indication indicates a degree of fitting of the ear mould.

24. A listening system comprising a listening device according to claim 20 AND an auxiliary device, the listening device and the auxiliary device being adapted to establish a communication link between them to provide that information can be exchanged or forwarded from one to the other.

25. A listening system according to claim 24 wherein an alarm indication concerning the degree of fitting of the ear mould of a listening device of the system is provided in the auxiliary device.

26. A listening system according to claim 24 adapted to provide that the probe signal generator for applying a probe signal to the output signal of the listening device(s) is controllable from the auxiliary device.