EP2230860A1 - Method for regulating a directional characteristic of a hearing aid - Google Patents

Abstract

The adjustment of the directional characteristic of a hearing device and in particular a hearing aid should be improved. Therefore, a method is provided in which a microphone signal (m) having a plurality of frequency bands, is obtained from an input sound with a microphone system of at least two microphones (10, 11). In addition, a property of the microphone signal (m), z. B. determines the level (p). The directional characteristic of the microphone system is set as a function of the determined property (p) of the microphone signal (m). To set the directional characteristic, two or more frequency bands are combined as a function of the determined characteristic of the microphone signal. Alternatively, one of the microphones can be attenuated, so that the directionality of the directional microphone is deliberately reduced.

Description

Method for setting a directional characteristic and hearing device

The present invention relates to a method for adjusting a directional characteristic of a hearing device by obtaining a microphone signal having a plurality of frequency bands, an input sound with a microphone system of at least two microphones, determining a property of the microphone signal and adjusting the directional characteristic of the microphone system in dependence on the determined property of the microphone signal. Moreover, the present invention relates to a corresponding hearing device. A hearing device is here understood to mean any sound-emitting device which can be worn in or on the ear or on the head, in particular a hearing aid, a headset, headphones and the like.

Hearing aids are portable hearing aids that are used to care for the hearing impaired. In order to meet the numerous individual needs, different types of hearing aids such as behind-the-ear hearing aids (BTE), hearing aid with external receiver (RIC: receiver in the canal) and in-the-ear hearing aids (IDO), e.g. Concha hearing aids or canal hearing aids (ITE, CIC). The hearing aids listed by way of example are worn on the outer ear or in the ear canal. In addition, bone conduction hearing aids, implantable or vibrotactile hearing aids are also available on the market. The stimulation of the damaged hearing takes place either mechanically or electrically.

Hearing aids have in principle as essential components an input transducer, an amplifier and an output transducer. The input transducer is usually a sound receiver, z. As a microphone, and / or an electromagnetic receiver, for. B. an induction coil. The output transducer is usually used as an electroacoustic transducer, z. B. miniature speakers, or as an electromechanical transducer, z. B. bone conduction, realized. The amplifier is usually integrated in a signal processing unit. This basic structure is in FIG. 1 shown using the example of a behind-the-ear hearing aid. In a hearing aid housing 1 for carrying behind the ear, one or more microphones 2 for receiving the sound from the environment are installed. A signal processing unit 3, which is also integrated in the hearing aid housing 1, processes the microphone signals and amplifies them. The output signal of the signal processing unit 3 is transmitted to a loudspeaker or earpiece 4, which outputs an acoustic signal. The sound is optionally transmitted via a sound tube, which is fixed with an earmold in the ear canal, to the eardrum of the device carrier. The power supply of the hearing device and in particular the signal processing unit 3 is effected by a likewise integrated into the hearing aid housing 1 battery. 5

From the publication WO 2007/096247 A1 is a hearing aid known in which can be switched back and forth between two modes of operation gently. In each channel of the output signal of a microphone system, an omni-directional signal and a directional signal are respectively formed. Depending on the level of the signal of the microphone signal, the omni-directional signal and the directional signal are mixed.

In addition, from the document US 2001/0038699 A1 an automatic directional control for a multi-microphone system known. The activation and deactivation of the directional processing is controlled depending on disturbances.

The patent DE 103 34 396 B3 discloses a hearing aid with a directional microphone system including at least three microphones. In each case several microphones are interconnected to microphone units, the order of the directional characteristic of these microphone units coincide. Finally, the microphone signals of these microphone units added, so that the order of the directional characteristic of the resulting microphone system corresponds to the order of the directional characteristic of the individual microphone units.

Further, the patent discloses DE 103 31 956 B3 a hearing aid in which different directional characteristics are adjustable. By changing delay times, the directivity is increased when the level is increased.

In the EP 1 489 882 A2 a method for operating a hearing aid is described in which microphone signals from microphone units with different directivity depending on a signal level of the microphone signals are weighted. Following the different weighting of the microphone signals of the directional microphones in the individual frequency bands, the output signals of the amplifiers are first added within the frequency bands. Due to the different weighting of the microphone signals of the directional microphones in the individual frequency bands, the directional characteristic in the individual frequency bands is optimized.

In the DE 103 27 890 A1 a method for operating a hearing aid is described in which weighted and summed for individual frequency bands a microphone signal of an omnidirectional microphone and a microphone signal of a microphone unit with directivity. The weighting adjusts a signal level of the microphone signals in the individual frequency bands. The method makes it possible to switch or superimpose in individual frequency bands between microphone units with different directional characteristics.

Modern hearing aids have powerful directional microphones, which are often adaptive and multi-channel realized. In addition, directional microphones can be activated and deactivated by situation detection algorithms. Overall, the complex directional microphone leads in modern hearing aids to an effective shading backward sources of interference and a sharply tuned club in front direction. Hearing aid wearers report in recent times, however, again and again that the directivity is too strong and the sensitivity of the side is already in a quiet noisy environment too weak and orientation and localization were disturbed.

The object of the present invention is thus to improve the setting of a directional characteristic of a hearing device and to provide a corresponding hearing device.

• Gewinnen eines Mikrofonsignals (m), das mehrere Frequenzbänder aufweist, aus einem Eingangsschall mit einem Mikrofonsystem aus mindestens zwei Mikrofonen (10, 11),
• Ermitteln einer Eigenschaft des Mikrofonsignals (m) und
• Einstellen der Richtcharakteristik des Mikrofonsystems in Abhängigkeit von der ermittelten Eigenschaft des Mikrofonsignals, wobei
• zum Einstellen der Richtcharakteristik zwei oder mehr Frequenzbänder in Abhängigkeit von der ermittelten Eigenschaft des Mikrofonsignals zu einem verbreiterten Frequenzband zusammengefasst werden und hierdurch für die zusammengefassten Frequenzbänder eine gemeinsame Richtcharakteristik bereitgestellt wird, welche im Vergleich zu Richtcharakteristiken für die zwei oder mehr Frequenzbänder verschliffen ist, so dass bei der gemeinsamen Richtcharakteristik eine Direktivität verringert ist.

According to the invention, this object is achieved by a method for setting a directional characteristic of a hearing device

• Obtaining a microphone signal (m) having a plurality of frequency bands from an input sound with a microphone system comprising at least two microphones (10, 11),
• Determining a property of the microphone signal (m) and
• Adjusting the directional characteristic of the microphone system as a function of the determined property of the microphone signal, wherein
• for adjusting the directional characteristic, two or more frequency bands are combined into a widened frequency band as a function of the determined characteristic of the microphone signal and thereby a common directional characteristic is provided for the combined frequency bands, which is ground in comparison to directional characteristics for the two or more frequency bands such that in the common directional directivity is reduced.

• einem Mikrofonsystem aus mindestens zwei Mikrofonen (10, 11) zum Gewinnen eines Mikrofonsignals (m), das mehrere Frequenzbänder aufweist, aus einem Eingangsschall,
• einer Analyseeinrichtung (13) zum Ermitteln einer Eigenschaft des Mikrofonsignals (m) und
• einer Verarbeitungseinrichtung (12) zum Einstellen der Richtcharakteristik des Mikrofonsystems in Abhängigkeit von der ermittelten Eigenschaft des Mikrofonsignals (m), wobei
• von der Verarbeitungseinrichtung (12) beim Einstellen der Richtcharakteristik zwei oder mehr Frequenzbänder in Abhängigkeit von der ermittelten Eigenschaft des Mikrofonsignals (m) zu einem verbreiterten Frequenzband zusammenfassbar sind und hierdurch für die zusammengefassten Frequenzbänder eine gemeinsame Richtcharakteristik bereitstellbar ist, welche im Vergleich zu Richtcharakteristiken für die zwei oder mehr Frequenzbänder verschliffen ist, so dass bei der gemeinsamen Richtcharakteristik eine Direktivität verringert ist.

In addition, the invention provides a hearing device

• a microphone system comprising at least two microphones (10, 11) for obtaining a microphone signal (m) having a plurality of frequency bands from an input sound,
• an analysis device (13) for determining a property of the microphone signal (m) and
• a processing device (12) for adjusting the directional characteristic of the microphone system as a function of the determined characteristic of the microphone signal (m), wherein
• two or more frequency bands depending on the determined property of the microphone signal (m) can be combined to form a widened frequency band by the processing device (12) and thus a common directional characteristic can be provided for the combined frequency bands, which compared to directivity characteristics for the two or more frequency bands are ground, so that in the common directional directivity is reduced.

Advantageously, it is possible to deliberately deteriorate the directionality of a microphone system in response to the ambient switch. This reduction in directionality creates directionality in certain listening situations that more closely matches natural sound perception and promotes localization.

Preferably, the characteristic of the microphone signal that is detected comprises the level of the microphone signal. This means that the directional characteristic can be adjusted depending on the level of the microphone signal. It is particularly advantageous to increase the directionality of the microphone system with increasing level. At a very low level, a directional microphone with only one very wide channel is offered.

Optionally, the characteristic of the microphone signal may also characterize one of several predetermined acoustic situations. This allows the directionality of the microphone system in dependence on a predefined complex acoustic situation, such as "speech in noise", control.

According to one embodiment of the invention, it is possible that the number of combined bands is changed manually and the current number is learned together with the current property of the microphone signal for later automatic adjustment of the hearing. Thus, the polishing of the directional characteristics, which are optimal for the individual frequency bands, is stored for the individual hearing situations in the hearing device and can then be set automatically upon recognition of such a hearing situation.

Optionally, it is possible to switch from a static operating mode to an adaptive operating mode. This would also be perceptive for achieving the o. G. Goal, since a static directional microphone in quiet environments attenuates sounds from the rear half-plane only moderately. An adaptive directional microphone, on the other hand, would be perceived as significantly more powerful in noisy environments.

• Gewinnen eines Mikrofonsignals aus einem Eingangsschall mit einem Mikrofonsystem, das mindestens zwei Mikrofone aufweist,
• Ermitteln einer Eigenschaft des Mikrofonsignals und
• Einstellen der Richtcharakteristik des Mikrofonsystems in Abhängigkeit von der ermittelten Eigenschaft des Mikrofonsignals, wobei
• zum Einstellen der Richtcharakteristik eines der beiden Mikrofone in Abhängigkeit von der ermittelten Eigenschaft des Mikrofonsignals bedämpft wird oder beide Mikrofone in Abhängigkeit von der ermittelten Eigenschaft des Mikrofonsignals zueinander fehlangepasst sind und hierdurch eine Direktivität der Richtcharakteristik verringert wird.

The above-mentioned object, to achieve a better adjustment of the directional characteristic, is also achieved according to the invention by a method for setting a directional characteristic of a hearing device

• Obtaining a microphone signal from an input sound with a microphone system having at least two microphones,
• Determining a property of the microphone signal and
• Adjusting the directional characteristic of the microphone system as a function of the determined property of the microphone signal, wherein
• for adjusting the directional characteristic of one of the two microphones in response to the determined property of the microphone signal is attenuated or both microphones are mismatched depending on the determined characteristic of the microphone signal to each other and thereby a directivity of the directional characteristic is reduced.

• einem Mikrofonsystem, das mindestens zwei Mikrofone aufweist, zum Gewinnen eines Mikrofonsignals aus einem Eingangsschall,
• einer Analyseeinrichtung zum Ermitteln einer Eigenschaft des Mikrofonsignals und
• einer Verarbeitungseinrichtung zum Einstellen der Richtcharakteristik des Mikrofonsystems in Abhängigkeit von der ermittelten Eigenschaft des Mikrofonsignals, wobei
• von der Verarbeitungseinrichtung beim Einstellen der Richtcharakteristik eines der beiden Mikrofone in Abhängigkeit von der ermittelten Eigenschaft des Mikrofonsignals bedämpfbar ist oder beide Mikrofone in Abhängigkeit von der ermittelten Eigenschaft des Mikrofonsignals zueinander fehlangepasst werden, so dass eine Verringerung einer Direktivität der Richtcharakteristik bewirkt wird.

Furthermore, a hearing device is also provided here

• a microphone system having at least two microphones for obtaining a microphone signal from an input sound,
• an analysis device for determining a property of the microphone signal and
• a processing device for adjusting the directional characteristic of the microphone system as a function of the determined characteristic of the microphone signal, wherein
• is attenuatable by the processing device when adjusting the directional characteristic of one of the two microphones in dependence on the determined characteristic of the microphone signal or both microphones are mismatched depending on the determined characteristic of the microphone signal to each other, so that a reduction of directivity of the directional characteristic is effected.

In this method or in this hearing apparatus, too, it is advantageously possible to intentionally worsen the directionality as a function of a hearing situation, namely by attenuating one of a plurality of microphone signals. Steaming automatically reduces the directional characteristics of the microphone system. The same effect of reducing directionality can be achieved by deliberately mismatching the microphones with each other. This can be achieved for example by a phase rotation of the microphone signal.

In a particular embodiment, the attenuation or mismatch may occur depending on a current amplification of the hearing device. Then it is not necessary Specifically for the adjustment of the directional characteristic to determine a property directly of the microphone signal and to change the directional characteristic accordingly. Rather, as a clue for the adjustment of the directional characteristic, the gain can be used, which indirectly reflects the level of the microphone signal via the implemented amplification characteristic of the hearing device.

If the microphone system has a front and a rear microphone with respect to a given wearing position of the hearing device, it is advantageous to damp the rear microphone to reduce the directionality. As a result, a frontal alignment of the directional characteristic is preserved rather than the case that a front or a middle microphone is attenuated.

FIG 1

den prinzipiellen Aufbau eines Hörgerätes gemäß dem Stand der Technik;

FIG 2

eine Schaltplanskizze der Signalverarbeitungsein- heit eines erfindungsgemäßen Hörgeräts;

FIG 3

eine Abhängigkeit des Artikulations-Index- Direktivitäts-Index vom Pegel;

FIG 4

ein Richtdiagramm bei zusammengefassten Frequenzka- nälen und

FIG 5

eine Abhängigkeit der Anzahl der zusammengefassten Kanäle vom Pegel.

The present invention will now be described with reference to the accompanying drawings, in which show

FIG. 1

the basic structure of a hearing aid according to the prior art;

FIG. 2

a circuit diagram of the signal processing unit of a hearing aid according to the invention;

FIG. 3

a dependence of the articulation index directivity index on the level;

FIG. 4

a directional diagram for combined frequency channels and

FIG. 5

a dependence of the number of combined channels on the level.

The embodiments described in more detail below represent preferred embodiments of the present invention.

The idea of the invention is that the effect of the directional microphone is ground, that is, artificially degraded. This smoothing is adaptive depending on the acoustic environment or personal preference. As features or properties of the acoustic environment are level criteria, or even the result of an arbitrarily fine situation recognition conceivable. The personal preference can for example be applied by the indirect hearing aid wearer via a control element. Optionally, the manually selected setting in the hearing device or in the hearing aid is stored together with the level or a situation identifier, d. H. learned. After a learning phase, the learned grinding can be performed automatically in the particular measure learned in the presence of a specific hearing situation or a specific level.

The inventive idea may, for example, in a hearing aid with the circuit components according to FIG. 2 be technically realized. The microphones 10 and 11 (it may also be more than two microphones) each produce a signal which is supplied to a microphone unit 12. This microphone unit 12 processes the signals into a resulting microphone signal m. The processing can take place in several frequency bands in parallel. In the microphone unit 12, the microphones 10 and 11 are interconnected as needed to an omnidirectional microphone or a directional microphone with variable directionality.

The output signal m of the microphone unit 12 is fed to a level meter 13. This level meter 13 symbolizes any analysis unit that analyzes the microphone signal m or the underlying hearing situation. The level p of the level meter 13 or a corresponding hearing situation identifier is returned to the microphone unit 12. Depending on the level or the situation identifier then the directionality is optionally changed to omni-directionality.

The microphone signal m is then subjected to a usual signal processing of a processing unit 14. Finally, the output signal of the signal processing unit 14 is converted by a receiver 15 into sound.

In FIG. 3 is indicated, which effects the microphone unit 12 of FIG. 2 for example. In principle, the aim here is that the directionality (measured, for example, with the AIDI = Articulation Index Directivity Index) is tracked as a function of the input level. In particular, a low directivity should be given at low levels and a correspondingly higher directivity at high levels. According to the present example of FIG. 3 Therefore, the value AIDI initially increases linearly from an initial value until it reaches a maximum level at which it remains. This characteristic can be stored in a similar manner in the microphone unit for setting the directional characteristic.

In order to influence the directivity of a microphone system and in particular to worsen its directivity targeted, in particular, the following two options are available. On the one hand, the microphone signal of that microphone can be attenuated, which is arranged further behind when carrying the hearing device with respect to the forwards direction of the user. So one of the two microphones 10 or 11 is deliberately damped. Alternatively, the two microphones can also be mismatched to each other, ie it is an artificial mismatch between front and rear microphone brought about. This effectively leads to a lower attenuation of rear sounds, because the directivity decreases with the attenuation or the mismatch. For adapting to the environment, the attenuation or mismatch is then adjusted adaptively and the hearing aid offers more directionality as the level increases.

In the described adaptation, it is necessary that, for example, the level of the input signal, d. H. the microphone signal is measured. In order to avoid a special measuring device for this purpose, the damping of the rear microphone can also be done depending on the applied gain. The gain is indirectly a measure of the level of the input signal. Thus, due to the non-linear processing of hearing aids, for example, for high gains (realized with quiet input signals), the directionality can be reduced.

As a further measure for deliberately reducing the effect of a directional microphone, the combination of microphone channels or frequency channels can be considered. For this it is necessary to first know the mode of action of a special directional microphone type. This directional microphone type is characterized by the fact that the directional characteristic is set separately in the individual frequency bands. The adjustment is made by minimizing the level of the most dominant interferer in the rear half plane. Thus, the most dominant interferer is hidden in each frequency band. However, this may result in too high and undesirable directivity can be achieved. Therefore, the directivity is reduced according to the invention according to the second method. This method consists of combining several frequency bands depending on the level or listening situation before determining the most dominant interferer. This summary is in the FIG. 4 exemplified by two channels. At a first channel, for example, at 500 Hz results in a directional diagram, the directional characteristic 16 (dashed line) with strong Notches (constrictions) in 90 ° and 270 ° direction. In a second frequency band, for example, around 1000 Hz results in a different directional characteristic 17 (dotted line). The Notches this directional characteristic 17 are further directed to the rear. Now, if the signals of the two frequency bands are added, the two directional characteristics are ground to a common directional characteristic 18 (solid Line). The common directional characteristic 18 has significantly less pronounced Notches and the directivity is reduced accordingly. To the outline sketch of FIG. 4 It should be noted that it merely illustrates symbolically how the directional characteristics can change as a result of combining frequency bands. In any case, it shows the principle that combining the microphone channels or the frequency bands results in a lower overall directionality.

The combining of the frequency bands can be done depending on a desired criterion. This criterion may again refer to a property of the microphone signal. For example, the directionality may depend on a determined hearing situation. Alternatively, the directionality can also be adapted level-dependent. In particular, the directionality can be increased with increasing ambient level. This will be according to FIG. 5 achieved in that the number k of the combined frequency bands or channels decreases with the level. In the present example, four bands are combined at low levels, only 3 or 2 at medium levels and only one channel for directionality at higher levels. This means that at low levels, the directivity is more sharpened than at high levels. From the above features results for the hearing aid user the advantage of being able to benefit in noisy environments of the full performance of a directional microphone, while the directionality z. B. decreases with decreasing ambient level and thus the localization ability and responsiveness from the rear remains guaranteed. The combination of frequency channels for the deliberate reduction of directionality has the additional advantage that the cost of design and construction of directional hearing aids can be reduced, because for arranging the microphones or the separation of microphone and handset to prevent feedback more freedom to disposal. Typically, the rear microphone is more sensitive mechanical feedback. In the case of an adaptive damping of the rear microphone, the expenditure for the construction and production can be reduced here, since the system has a lower feedback sensitivity due to the artificial attenuation.

Claims (11)

Method for setting a directional characteristic of a hearing device Obtaining a microphone signal (m) having a plurality of frequency bands from an input sound with a microphone system comprising at least two microphones (10, 11), - Determining a property of the microphone signal (m) and Adjusting the directional characteristic of the microphone system as a function of the determined characteristic of the microphone signal,
characterized in that two or more frequency bands are combined to form a broadened frequency band as a function of the determined characteristic of the microphone signal and thus a common directional characteristic is provided for the combined frequency bands, which is ground in comparison to directional characteristics for the two or more frequency bands that in the common directional directivity is reduced. The method of claim 1, wherein the characteristic of the microphone signal comprises its level. The method of claim 2, wherein the directionality of the microphone system with increasing level (p) is increased. Method according to one of the preceding claims, wherein the characteristic of the microphone signal (m) characterizes one of a plurality of predetermined acoustic situations. Method according to one of the preceding claims, wherein the number (k) of the combined bands is changed manually and the current number is learned together with the current characteristic of the microphone signal (m) for a later automatic adjustment of the hearing device. Method according to one of the preceding claims, wherein is switched from a static mode of operation, in which the number of combined frequency bands is fixed, in an adaptive mode of operation, in which the number of combined frequency bands is automatically adapted to the current situation. Hearing device with a microphone system comprising at least two microphones (10, 11) for obtaining a microphone signal (m) having a plurality of frequency bands from an input sound, - An analysis device (13) for determining a property of the microphone signal (m) and - a processing means (12) for adjusting the directivity of the microphone system in dependence on the determined characteristic of the microphone signal (m), characterized in that - By the processing means (12) when setting the directional characteristic two or more frequency bands in response to the determined property of the microphone signal (m) are summarized to a widened frequency band and thereby a common directional characteristic is provided for the combined frequency bands, which compared to directional characteristics for the two or more frequency bands are ground, so that directivity is reduced in the common directional characteristic. Method for setting a directional characteristic of a hearing device Obtaining a microphone signal (m) from an input sound with a microphone system having at least two microphones (10, 11), - Determining a property of the microphone signal (m) and Adjusting the directional characteristic of the microphone system as a function of the determined characteristic of the microphone signal (m),
characterized in that - For adjusting the directional characteristic of one of the two microphones (10, 11) in response to the determined property of the microphone signal (m) is attenuated or both microphones in dependence on the determined property of the microphone signal (m) are mismatched to each other and thereby a directivity of the directional characteristic is reduced. The method of claim 8, wherein the damping or mismatching occurs in response to a current gain of the hearing device. The method of claim 8 or 9, wherein the microphone system has a respect to a predetermined wearing position of the hearing front and a rear microphone, and the rear microphone is attenuated. Hearing device with a microphone system comprising at least two microphones (10, 11) for obtaining a microphone signal (m) from an input sound, - An analysis device for determining a property of the microphone signal (m) and - A processing device (12) for adjusting the directional characteristic of the microphone system as a function of the determined property of the microphone signal (m), characterized in that - By the processing means (12) when adjusting the directional characteristic of one of the two microphones (10, 11) in response to the determined property of the microphone signal (m) is attenuated or both microphones (10, 11) in dependence on the determined characteristic of the microphone signal to each other be mismatched so as to cause a reduction in directivity of the directional characteristic.

Images