Method for operating a hearing device, and hearing device system
A signal processor of a hearing device has a feedback canceller for determining and, if present, canceling feedback. A method of operating the hearing device includes retrieving for a predetermined sample period a set of data of the feedback canceller that represents an acoustic feedback path between the speaker and the microphone; reducing an amount of the data within the set of data; applying a denoising step to the set of data; generating a representative set that is representative for the data within the set; inputting the representative set to a neural network that is trained to retrieve from the input data a measure indicating proper or improper positioning of the hearing device within the ear canal; and issuing a notice to a user of the hearing device at least when the measure indicates an improper positioning.
1. A method of operating a hearing device, the hearing device having a microphone for receiving ambient sound, a signal processor for processing a microphone signal based on the received ambient sound into an output signal, a speaker for outputting the output signal, and the signal processor including a feedback canceller for determining and, if present, canceling feedback, the method comprising:
retrieving for a predetermined sample period a set of data of the feedback canceller that represents an acoustic feedback path between the speaker and the microphone;
applying at least one step of reducing an amount of data within the set of data;
applying a denoising step to the set of data;
generating a representative set that is representative for the data within the set of data;
inputting, directly or indirectly, the representative set to a neural network that is trained to retrieve from the input data a measure indicating a proper positioning or an improper positioning of the hearing device within the ear canal; and
issuing a notice to a user of the hearing device when the measure indicates an improper positioning of the hearing device.
2. The method according to claim 1 , which comprises also issuing a notice to the user of the hearing device when the measure indicates a proper positioning of the hearing device.
3. The method according to claim 1 , wherein the data retrieved from the feedback canceller comprise adaptive filter coefficients determined by the feedback canceller.
4. The method according to claim 1 , which comprises transforming the set of data retrieved from the feedback canceller to the frequency domain before applying any further data manipulation steps.
5. The method according to claim 4 , wherein the set of data transformed to the frequency domain contains a plurality of magnitude arrays) and phase arrays).
6. The method according to claim 5 , wherein the magnitude array) and the phase array) have a length of 64.
7. The method according to claim 1 , which comprises subtracting from the representative set a hardware correction curve to compensate for device specific frequency-shaping effects.
8. The method according to claim 7 , which comprises, after subtracting the correction curve, applying within the step of reducing the amount of data a principal component analysis transformation to the representative set.
9. The method according to claim 8 , which comprises using the principal component analysis transformation to reduce a dimensionality of the set of data by a factor of two to four.
10. The method according to claim 8 , which comprises, before applying the principal component analysis transformation, joining together the averaged magnitude and phase arrays for a joint representative set.
11. The method according to claim 7 , wherein the step of reducing the amount of data comprises applying a principal component analysis transformation to the representative set.
12. The method according to claim 11 , which comprises using the principal component analysis transformation to reduce a dimensionality of the set of data by a factor of two to four.
13. The method according to claim 1 , wherein steps of denoising and of generating the representative set comprise applying an averaging to the set of data of the respective sample period.
14. The method according to claim 13 , wherein the step of averaging comprises a time averaging.
15. The method according to claim 1 , which comprises performing a further step of reducing the amount of data by discarding frequency channels of predetermined high and low frequency bands from the set of data.
16. The method according to claim 15 , which comprises carrying out the further step of reducing the amount of data before the denoising step.
17. The method according to claim 1 , which comprises using as the neural network a shallow feed-forward multi-layer perceptron neural network containing only few hidden layers.
18. The method according to claim 17 , wherein the neural network contains three or fewer hidden layers.
19. A hearing device system, comprising:
a hearing device comprising a microphone for receiving ambient sound, a signal processor for processing a microphone signal based on the ambient sound received by said microphone into an output signal, a speaker for outputting the output signal;
said signal processor including a feedback canceller configured for determining and, if present, canceling feedback; and
a controller configured to perform the method according to claim 1 .