Patent Application
20050105750
This application claims priority to the German application No. 10347211.8, filed Oct. 10, 2003 and which is incorporated by reference herein in its entirety.
The present invention relates to a method for retraining a hearing aid by provision of an acoustic input signal, provision of two or more hearing situation identifications and association of the acoustic input signal with one of the hearing situation identifications by a hearing aid wearer. The present invention furthermore relates to a corresponding hearing aid which can be retrained, and to a method for operation of a hearing aid such as this after retraining.
Classifiers are used in hearing aids in order to identify different situations. The preset parameters need not, however, necessarily be optimal for the corresponding situations for an individual hearing aid wearer. In specific situations, the identification rate with regard to the individual constraints can be improved by retraining, as is normally used for speaker-related speech recognition systems. This is of particular importance especially for the situation in which the wearer's own voice is being presented. The classifier may likewise be set optimally for specific noise Situations, which are typical of the acoustic environment of the hearing aid wearer.
In this context, the document EP 0 681 411 A1 discloses a programmable hearing aid, which automatically matches itself to changing environmental situations. The hearing aid parameters are in this case continuously matched to the existing environmental noise, in which case “fuzzy” inputs from the hearing aid wearer may be used in addition to the measured input signals. The objective in this case is to optimize the parameters directly, although the hearing situation is not described explicitly.
Furthermore, the document EP 0 814 634 A1 describes a method by means of which the hearing aid wearer sets the hearing aid optimally himself by carrying out a retraining process which he initiates himself. For selection purposes, the hearing aid wearer is provided with a range of predefined parameter sets for that hearing situation which he signals to the hearing aid. From this limited range of parameter sets, which each correspond to one hearing aid preset, he selects that which he finds to be the optimum. The corresponding hearing aid setting is learnt by a control mechanism, so that the same hearing aid setting is produced for a similar acoustic input Signal. This means that the control mechanism maps the acoustic input variables onto the Optimum hearing aid Parameter Set. During this retraining process, the hearing Situation is taken into ac-count only indirectly, by making available for selection only those Parameter sets which correspond to this hearing Situation. However, direct matching of the hearing Situation to the acoustic input data is not carried out. This has the disadvantage that the hearing aid wearer has to assess the sound of the hearing aid, which is defined by the Parameter set being used, during such retraining. For example, he has to assess whether he wishes to be presented with the sound in a lighter or darker form. However, it is difficult, or even completely impossible, for the hearing aid wearer to distinguish between different Parameter sets for certain complex algorithms and dynamic adaptive Parameters, for example for controlling an adaptive directional microphone.
An object of the present invention is thus to simplify the retraining of a hearing aid for the hearing aid wearer, and to correspondingly improve the Operation of the hearing aid.
According to the invention, this object is achieved by the claims.
The invention is based on the discovery that, although it is difficult for the hearing aid wearer to distinguish between different Parameter Sets, the hearing aid wearer can in most cases very reliably name an acoustic Situation which currently exists, for example the Situation of “his own voice” or “being located in an automobile”. These Situations go beyond the hearing Situations that are conventionally used in hearing aids, such as “Speech in a quiet environment” and “Speech in the presence of interference noise”. This means that the hearing Situations between which a distinction is being drawn may relate to those aspect elements of these “classical” Situations which are relevant to Signal processing. The acoustic more representations on which these novel, comprehensive Situations are based, may be retrained individually in a simple manner by naming them specifically. For example, the sound of the hearing aid wearer's own voice or the specific sound of his own automobile may be learnt by the hearing aid, for example by means of a neural network. Thus, in contrast to the cited prior art according to EP 0 813 634 A1, the neural network does not map the acoustic input variables onto the resultant Overall Setting (Parameter Setting) of the hearing aid, but maps it onto the internal Situation representation (hearing Situation identification). The hearing aid Parameter Set to be used is then derived from this on the basis of audiological expert knowledge, with the relevant Parameters being varied and/or supplemented. In particular, the adaptive algorithms can use this information further without the hearing aid wearer having to assess the results. This simple association between the acoustic input Signal and predetermined hearing Situations is far less difficult for the hearing aid wearer than direct sound assessment such as assessment of the frequency response and/or compression relationships/knee Points, according to the prior art, owing to the adaptivity of the algorithms and the time dynamic response associated with them.
In one specific refinement according to the invention, one of the hearing Situations may correspond to the presentation of the hearing aid wearer's o m voice, so that his own voice can be identified once it has automatically be learnt. This is of major importance in many Situations, for example for directional microphone adjustment.
The automatic learning of the at least one hearing aid Setting Parameter for the associated hearing Situation on the basis of the automatic evaluation may be carried out during (online) or after (offline) the presentation of the acoustic input Signal. During online retraining, the acoustic input Signal need not be stored completely, although the hearing aid requires more computation power in Order to carry out the retraining process. In the case of off-line retraining, there is no need for this additional computation requirement in the hearing aid, although a Storage apparatus is required for the acoustic input Signal. Online evaluation avoids and the time-consuming reading, processing reprogramming of the data and/or of the hearing aid.
The input device for association of the acoustic input Signal with a hearing Situation may also be used for starting and stopping the retraining process. This simplifies the handling of the hearing aid and the process of carrying out the retraining for the hearing aid wearer.
Furthermore, the input device may comprise a receiver integrated in the hearing aid, or an external remote control. The remote control may be designed to communicate with the hearing aid with or without the use of wires. It is also feasible for the remote control to be used exclusively for retraining of the hearing aid. Alternatively, the remote control may be in the form of a multifunction device, for example a mobile telephone or a Portable Computer with a radio interface.
The input device may also comprise a programmable computation unit, in particular a PC, so that it is operated via appropriate programming Software.
Finally, in one specific embodiment, the input device may be operable verbally and, in particular, by means of one or more keywords. This makes the Operation of the hearing aid even more convenient for the hearing aid wearer.
Furthermore, the acoustic input Signal may comprise a Speech Signal which is preprocessed manually or automatically. This makes it possible to train the classifier very specifically.
During Operation of the hearing aid, that is to say after the retraining process, a currently applicable Parameter Set may be influenced by the automatic association between the current hearing Situation and hearing Situation identification. In particular, a Parameter in the Parameter Set may be varied and/or supplemented by the automatic association process. It is thus possible for the acoustic input Signal to be subjected to complex Signal processing on the basis of expert knowledge, when the neural network identifies a hearing Situation that it has learnt, for example a wearer's own voice. In this case, the Parameter Set which is currently used in the hearing aid may be appropriately modified, with appropriate filtering Operations being carried out.
The present invention will now be explained in more detail with reference to the attached drawings, in which:
The exemplary embodiment which will be described in more detail in the following text represents one preferred embodiment of the present invention. However, in Order to assist understanding of the invention, the method for retraining on the basis of the prior art will first of all be explained in more detail once again, with reference to
The hearing aid wearer or User 1 is in a specific acoustic Situation, as is illustrated in
A neural network 5 learns the desired Parameter Set 4 for the present acoustic input Signal 2, so that it will also once again select this Parameter Set 4 for a similar acoustic Situation after the training Phase. The subjective assessment of the Sounds, resulting from the different Parameter Sets for hearing aid Setting, is, however, very difficult for the hearing aid wearer 1, since this is dependent on large amounts of detailed knowledge about the effects of the hearing aid Parameters.
Thus, according to the present invention, the aim is for the hearing aid to be trained only by identification of the current Situation, rather than by using specific Parameter Sets. This is done in a corresponding manner to the method shown in
The neural network 5 therefore does not learn the association between a Parameter Set and the acoustic input Signal 2, but the association between a defined hearing Situation or a hearing Situation identification 3′ and the acoustic input Signal 2 (See the arrows with solid lines in
According to the invention, in contrast, the Situation of the “wearer's own voice” and the further Situation of “in his own automobile” are learnt separately. These hearing Situations each have a specific influence on the complex Signal processing. This results, for example, in the Situation of the “wearer's own voice” in a specific gain, possibly linked to a specific Setting of the directional effect of the hearing aid, and, in the Situation “in his own automobile” in interference noise Suppression that is once again highly specific in the hearing aid.
It is particularly advantageous that the hearing aid can learn the wearer's own voice. This is done by subjecting the acoustic input Signal with the wearer's own voice to specific processing, by specifically Setting appropriate Parameters for the hearing aid, and by associating this with the hearing Situation of the “wearer's own voice”. A similar Situation applies to the learning, for example, of the hearing Situation of “his own automobile”, thus resulting in the capability to achieve highly specific interference noise Suppression. Thus, during the learning process, not only is the input Signal associated with a hearing Situation, but Parameters such as filter or gain Parameters are also determined highly specifically.
During use of the hearing aid after the retraining process, the neural network 5 associates an acoustic input Signal 2 with one or more specific hearing Situation identifications 3′, so that the currently applicable Parameter Set 4′ (including filter Parameters) is influenced appropriately. A complex Signal processing unit 6, for example with an adaptive directional microphone, will carry out the Signal processing on the basis of the influenced Parameter Set 4′. If, on the basis of the above example, the neural network now receives the input Signal “the wearer's own voice in his own automobile”, it associates this not only with the hearing Situation identification “the wearer's own voice” but also with the hearing Situation identification “in his own automobile”, so that the current Parameter Set is varied or supplemented, for ex-ample in terms of the specific gain, for his own voice and with respect to the specific filtering for Suppression of the interference noise in his own automobile.
Two specific exemplary embodiments of the present invention will be described in the following text:
An adaptive directional microphone is pointing in the direction from which the maximum useful sound, for example a Speech Signal, is arriving. If the hearing aid wearer is having a conversation with someone Walking alongside him, the directional microphone should be Set to the conversation Partner, that is to say to a maximum gain at an angle of about 90″. However, as soon as the hearing aid wearer speaks himself, the useful sound Signal Comes from his own mouth, that is to say from an angle of 0″. His own Speech thus draws the directional microphone characteristic away from the actual conversation Partner, to be precise normally with a certain time delay. If, in contrast, the hearing aid is trained to his own voice so that the adaptive microphone control which is associated with acoustic characteristics for his own voice is thus known, signals which are classified as “his own voice” can be ignored for the readjustment of the directional characteristic. This would be in contrast to the adjustment capability for the hearing aid according to the prior art from
An interference noise Suppression method can be specifically trained for complex noise which varies with time. This noise is then optimally suppressed, even though it may have similar spectral components or a modulation spectrum like Speech which should still be processed as a useful Suppression method can by individual training example the Situation mentioned above, by, Signal. The interference noise be automatically optimally Set for this acoustic Situation, for of “in his own automobile” as for example, Setting specific weighting factors for individual spectral bands, or by optimally matching the dynamic response to the interference noise characteristic. In this Situation as well, the differences between the Set-tings for the dynamic interference noise Suppression can be directly assessed only with difficulty while, in contrast, the Situation can be assessed very reliably.
In certain acoustic Situations, it may be advantageous to carry out retraining on the basis of the prior art in addition to the retraining according to the invention, in Order to allow the hearing aid wearer to assess different Parameter Sets.
The retraining process, as it appears to the hearing aid wearer, win now be explained in more detail with reference to
A number of hearing Situations are stored in the classifier. The hearing aid wearer knows that the hearing Situation “his own voice” corresponds, for example, to the Situation 3. He thus presses the push button 13 three times in Order to Signal to the classifier that the aim is to retrain the Situation 3.
In a subsequent step, an acoustic Signal (in this case the wearer's own voice) is presented to the hearing aid 10 for reception, as shown in
The actual retraining of the hearing aid 10 can be carried out while the acoustic Signal 14 is being presented. Alternatively, the acoustic Signal 14 is recorded in the hearing aid and is evaluated after being recorded, and is associated with the selected hearing Situation on the basis of characteristic acoustic properties. In the case of online retraining, the acoustic Signal 14 need not necessarily be permanently or temporarily stored.
Since the hearing aid 10 need be signaled only with the information about the current Situation, it is not absolutely necessary to have an external control unit, in contrast to the prior art according to EP 0 814 634 A1. However, this may be used for convenience reasons, for example as shown in
After the retraining process, the identification rate of the classifier can be increased considerably for specific Situations over the preset level, so that the hearing aid is Set more reliably in this Situation. The automatic starting and ending of the retraining phase by the hearing aid wearer also makes it possible to carry out reliable retraining for certain Situations, since the hearing aid wearer himself decides when the Signal can be associated with the Situation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10347211.8 | Oct 2003 | DE | national |
