EP1962556A2 - Method for improving spatial awareness and corresponding hearing device - Google Patents

Abstract

The method involves receiving an input signal of a binaural hearing apparatus, and processing of the input signal into an output signal that leads to spatial perception. A variable of the output signal of the hearing apparatus is controlled, based upon the input signal, such that spatial perception is altered. The input signal is analyzed by separating sound sources and determining a fading of the input signal, where the separation is effected via a directional microphone or a blind source separation algorithm. An independent claim is also included for a hearing apparatus for binaural supply of a human hearing.

Description

The present invention relates to a method for the binaural supply of a human hearing by means of a binaural hearing device. Moreover, the present invention relates to a corresponding hearing aid for binaural care. A hearing device is understood to mean in particular a hearing device or a plurality of hearing aids as well as a headset or headphones.

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) and in-the-ear hearing aids (ITO), e.g. also Concha hearing aids or canal hearing aids (CIC), provided. 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. As a signal input but for example, an audio shoe into consideration, so that z. B. signals from a stereo system can be received. The output transducer is usually used as an electroacoustic transducer, z. As miniature speaker, or as an electromechanical transducer, z. B. bone conduction, realized. The amplifier is usually integrated in a signal processing unit. The latter usually creates a surround sound mixing for a free field, which in a room naturally arising spatiality is destroyed. 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 of the signal processing unit 3 is carried out by a likewise integrated into the hearing aid housing 1 battery. 5

Traditional hearing aid signal processing and the acoustics of hearing aids change the natural surround sound or reduce spatial perception. The sound quality suffers from this. The noise sensation is also affected. The brain is able to separate spatially differently perceived sources.

The aspects of spatial perception are rarely addressed today in hearing aids. It is only known that directional microphones influence the spatial transfer function and impair the quality of the signal in terms of natural perception. Thus, by reducing the effect of a directional microphone, the spatial perception can be improved, but this contradicts just the purpose of a directional microphone.

From the article by Anemüller, Jörn: "Blind source separation as preprocessing for robust speech recognition", DEGA 2000, Oldenburg describes how "blind source separation" can contribute to improved speech recognition. Here, a mixed signal from a useful and a source of interference is recorded with multiple microphones. By suitable filtering then the signals of the individual sources can be separated.

In addition, from the document DE 103 51 509 A1 a method for adapting a hearing aid with consideration of the head position is known. The starting point is that a "blind source separation" is used to separate the signals of spatially distributed sources. However, in a hearing aid this requires a certain adaptation time, which would have to be waited for every movement again. To avoid this, a position determination is provided for determining the current position of the head of the hearing device wearer, so that the position of the head in a processing unit allows the relative change of the sound source positions to be taken into account quickly.

The object of the present invention is therefore to propose a method and a corresponding hearing device with which an improved spatial perception is possible.

According to the invention, this object is achieved by a method for the binaural supply of a human hearing by means of a binaural hearing device by receiving an input signal of the hearing device, processing the input signal to an output signal that leads to a spatial perception, and controlling at least one size of the input signal based Output signal of the hearing such that the spatial perception is changed.

In addition, the invention provides a hearing aid for the binaural supply of a human hearing with a recording device for receiving an input signal of the hearing device, a processing device for generating an output signal that leads to a spatial perception, based on the input signal and a control device for controlling the processing device with respect at least one size of the output signal of Hearing apparatus such that the spatial perception is changed.

Advantageously, it is thus possible to restore or replicate parts of a "destroyed spatiality". Through targeted use of virtual spatial imaging, the brain can be helped to separate different sources without having to suppress them. Rather, for example, by introducing processing blocks into the signal path, the spatial impression can be restored or desired spatial effects can be achieved.

Preferably, the input signal or signals are analyzed and / or classified, and the control is performed according to the classification result. Thereby, the spatial perception can be influenced depending on certain types or types of input signals.

Analyzing the input signal (s) may also include determining the reverberation of the input signal. The control then takes place according to the reverberation. Thus, the control can be done, for example, depending on the acoustic situation of a room.

Furthermore, the analyzing may include separating sound sources, and controlling corresponding to the separated sound sources. Specifically, the separation can be done by a directional microphone and / or a blind source separation algorithm. This makes it possible to control the spatial reproduction as a function of specific useful sound sources or noise sources.

The analyzing may further include noise detection, and the controlling according to the noise component. Thus, the spatial reproduction independent of specific sound sources can be influenced as a whole depending on noise components.

In analyzing, moreover, a level of the input signal can be detected, so that the control of the spatial reproduction can be performed depending on the detected level. As a result, a desired spatial perception can be achieved in a simple manner as a function of the volume.

According to another embodiment, at least one z. B. via an audio shoe externally fed signal, if necessary, be detected in addition to a microphone signal, and the control carried out according to the detected signals. This can be achieved by specific spatial reproduction, for example, inductively fed signals in large lecture halls or churches a different spatial impression than in conventional microphone signals.

The spatial perception influencing variables may be a distance of a source from the hearing device, a spatial direction of a source with respect to a predetermined zero-degree direction of the hearing device, a source location and / or a property of the room reverb. These parameters significantly affect spatial rendering.

FIG 1

den prinzipiellen Aufbau eines Hörgeräts mit seinen wesentlichen Komponenten;

FIG 2

ein Blockschaltdiagramm eines erfindungsgemäßen Hörgeräts;

FIG 3

ein Prinzipschaltbild eines erfindungsgemäßen Hörgeräts mit FIR-Filter;

FIG 4

ein Schaltbild eines FIR-Filters (finite impulse response) und

FIG 5

Realisierungsformen des Verarbeitungsblocks für räumliche Wahrnehmung.

The present invention will be explained in more detail with reference to the accompanying drawings, in which:

FIG. 1

the basic structure of a hearing aid with its essential components;

FIG. 2

a block diagram of a hearing aid according to the invention;

FIG. 3

a schematic diagram of a hearing aid according to the invention with FIR filter;

FIG. 4

a circuit diagram of an FIR filter (finite impulse response) and

FIG. 5

Embodiments of the processing block for spatial perception.

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

• die Distanz der Quelle (n) vom Hörer; sie beeinflusst unter anderem das Verhältnis zwischen Direktschall und Reflexionen sowie die Ausprägung der ersten Wellenfront.
• die wahrgenommene Stereobreite; diese entspricht dem Raumwinkel, über den die Schallquellen verteilt sind.
• die Lokalisation der Quelle (n); dies entspricht der genauen Ortsbestimmung einer Quelle anhand von Winkel und Abstand.
• die Eigenschaften des Raumhalls; so lässt sich beispielsweise leiser Nachhall aus dem Signal entfernen.

The present invention is based on the recognition that there are numerous properties of binaurally presented audio signals that influence spatial perception. From audio technology, various methods are known, which influence these properties in the presence of a stereo signal, so that a desired perception is achieved. Target variables include:

• the distance of the source (s) from the listener; Among other things, it influences the relationship between direct sound and reflections as well as the characteristics of the first wavefront.
• the perceived stereo width; this corresponds to the solid angle over which the sound sources are distributed.
• the localization of the source (s); this corresponds to the exact location of a source based on angle and distance.
• the properties of the space reverb; For example, quiet reverberation can be removed from the signal.

For the invention, however, it is not absolutely necessary that stereo signals are present. Rather, the invention can also be applied to methods that simulate the head-related, spatial transfer function. The hearing aids can also receive exactly the same signals (eg mono signals).

The starting point for improving the spatial reproduction is that the algorithms present in a hearing aid (for example noise suppression) and the microphone positions can cause the naturally perceived sound to be alienated. Furthermore, the sources can be perceived very close to the head or even in the head, making it difficult to separate the sources while listening. Especially with the use of directional microphones, an improvement of the spatial reproduction may be necessary, because a directional microphone makes it possible to hide interference signals, but the sense of spatial perception is thereby also strongly negatively affected.

For improved spatial reproduction, it is therefore provided according to the invention to include one or more signal processing blocks in the signal path, possibly also in different channels or spatial signal parts, which influences one or more of the abovementioned target variables. The goal is either to restore a natural sound or to achieve certain virtual perceptions.

An example of a general structure of a hearing aid with such a signal processing block for improving the spatial perception is in FIG. 2 shown schematically. As in the example of FIG. 1 one or more microphones 2 are connected to a signal processing unit 3. The latter serves practically as a processing and control device. As an analysis device, the processing unit 3 has a classifier 6, which provides a corresponding classification signal as an output signal. In addition to the microphone input signals, the signal processing unit 3 may optionally have further inputs. For example, a signal H2 from a hearing aid on the other side of the head can be used as an input signal. Furthermore, a signal EQ from an external source can be used as an input signal. For example, a signal from a stereo system can be coupled into the hearing aid via an audio shoe become. The output of signals of the processing unit 3 is optionally separated according to interference and useful signals.

In the example of FIG. 2 the signal processing unit 3 is followed by a directional microphone or BSS unit 7. This may provide a desired number of directional microphones or directional microphone settings. Optionally, signals are separated by so-called "blind source separation" (BSS). The directional microphone or BSS unit 7 can also be arranged between the microphones 2 and the signal processing unit 3. Then the microphone signals or the signals of the external sources and signals of the other side are fed into the directional microphone. However, a directional microphone / BSS processing is not mandatory for the present invention, so that it may be possible to dispense with a corresponding processing unit.

In the example of FIG. 2 The BSS unit 7 is followed by a processing block 8 for spatial processing. In addition to FIR filtering, this block can also have many other functions, as shown by FIG. 5 will be explained in more detail. The aim is to influence the interaural cross-correlation, possibly the interaural time difference for the direction perception or a suitable frequency response shaping. The processing of the signals is always carried out in this block 8 so that associated signals of the left and right side are changed in their spatial impression.

The output signals of the spatial processing block 8 are mixed in a subsequent mixing unit 9 with corresponding weights. The mixing as well as the spatial processing is controlled by the control or signal processing unit 3 or its classifier 6. The output signal of the mixing unit 9 is supplied to the loudspeaker or receiver 4.

In addition, it should be noted that the use of a control unit 3, as in the example of FIG. 2 is not mandatory. The parameters for the mixture and the spatial processing are then fixed. Furthermore, a very simple form of implementation can also be that only one signal each from left and right is processed and the mixture is eliminated.

For example, it may be favorable to increase the distance depending on the signal type. This is possible in a hearing aid according to the invention, for example, by the in FIG. 2 schematically reproduced structure. The hearing aid has at the signal input a microphone 10. Downstream is a signal processing 11, which has a classifier 12. In addition, the signal processing 11 is for the usual gain. The output signal of the signal processing 11 is branched to two filters or directional microphones 13, 14. In the one branch, a finite impulse response (FIR) filter 15 with constant amplitude response (all-pass) is furthermore provided. It ensures a certain phase shift of the signal. The signals of both branches are mixed in a mixer 16 and fed to a loudspeaker 17. The classifier 12 influences the phase shift of the FIR filter 15 and / or the mixing ratio in the mixer 16.

The FIR filter 15 is in FIG. 4 shown in concrete. A digital input signal ES is multiplied in fixed predetermined time delay stages (z ^-1 ) with different coefficients K1, K2, K3 and K4. The sum of the individual signals leads to an output signal AS. Depending on the choice of the coefficients, a corresponding phase or time shift of the signal results. If the shift in the left ear signal is different from the right one, the perception of space is different. It can be z. B. the direction and / or distance perception can be influenced.

1. 1. Klassifikation des Eingangssignals
   1. a) Einstellung der Verfahren mittels eines Klassifikators
      • i) Distanzerhöhung in Abhängigkeit des Signaltyps (z. B. Musik oder Sprache); sie lässt sich mithilfe des Aufbaus von FIG 2 erzielen, wie dies oben bereits geschildert wurde.
      • ii) Stereobreitenerhöhung in Abhängigkeit des Signaltyps (z. B. Musik oder Sprache); sie lässt sich bei binauraler Versorgung durch entsprechend unterschiedlichen Versatz des linken und rechten Signals erreichen.
      • iii) Zumischen von Hall in Abhängigkeit der Klasse; das Mischen und Steuern mithilfe des Klassifikators lässt sich ähnlich dem Prinzip von FIG 2 durchführen.
   2. b) Hallabängigkeit (Feststellung mit dem Klassifikator oder einer anderen geeigneten Analyseeinheit)
      • i) Distanzerhöhung in Abhängigkeit der Verhalltheit des Signals (z. B. wenn das Signal verhallt ist, soll die Distanzerweiterung geringer ausfallen);
      • ii) Stereobreitenerhöhung in Abhängigkeit der Verhalltheit des Signals (z. B. wenn das Signal verhallt ist, soll die Stereoverbreitung geringer ausfallen);
      • iii) Zumischung von Hall in Abhängigkeit des im Signal detektierten Hallanteils
   3. c) Virtuelles auditorisches Display
      • i) Klassenabhängige Verschiebung eines Signals in eine Raumrichtung (z. B. Verschiebung eines Störgeräuschs nach hinten);
      • ii) Beliebige Kombination des Verfahrens 1.c.i mit einem oder mehreren Verfahren von 1.a und/oder 1.b
2. 2. Richtmikrofon oder separierte Signale
   1. a) Richtungsfilterung mittels eines Richtmikrofons und darauf folgende Veränderung der Quellendistanz je nach Richtung statt einer reinen Unterdrückung (mehrere Richtcharakteristiken müssten parallel gerechnet werden).
   2. b) Veränderung der Quellendistanz von Signalen, welche mithilfe eines Blinde-Quellentrennung-Algorithmus (blind source separation: BSS) gewonnen wurden, unter Umständen in Abhängigkeit der Quellenrichtung und/oder Distanz.
   3. c) Kombination der Verfahren von 2.a und/oder 2.b mit einem oder mehreren der Verfahren aus 1.
3. 3. Extern eingespeiste Signale
   Neben dem bzw. den Mikrofonsignalen können auch andere Signale beispielsweise elektromagnetisch in die Hörvorrichtung/das Hörgerät eingekoppelt werden. Eine unterschiedliche Behandlung der Mikrofonsignale und der elektrisch eingespeisten Signale kann zu einer Verbesserung der räumlichen Wiedergabe führen. So könnten beispielsweise die Mikrofonsignale weiter entfernt oder nach hinten geblendet werden, wenn ein extern eingespeistes Signal (Telefon, Stereoanlage, FM-Anlage, etc.) vorliegt.
4. 4. Störanteil der Geräuschbefreiung
   Statt den Störanteil zu unterdrücken, kann er in einer einstellbaren Distanz bzw. Richtung dem Signal wieder zugemischt werden. Auch dies kann mit einer ähnlichen Schaltungsstruktur erfolgen, wie sie in FIG 2 dargestellt ist.
5. 5. Pegelabhängigkeit
   Entsprechend einer weiteren zusätzlichen oder alternativen Option wird die Stärke der Wirksamkeit der Verfahren in Abhängigkeit des Signalpegels eingestellt. Dies lässt sich einfach durch einen entsprechenden Pegelmesser realisieren, der in der Regel ohnehin vorhanden ist.
6. 6. Benutzersteuerung
   Entsprechend einer weiteren Option kann vorgesehen sein, dass der Benutzer die Wirksamkeit der Algorithmen beispielsweise mithilfe einer Fernbedienung manuell steuert. Damit wäre eine manuelle oder halbautomatische Steuerung möglich.
7. 7. Binaurale Verfahren
   Die Parameter der Verfahren werden nach einer Analyse der Signale für das rechte und das linke Ohr eingestellt. Hierzu ist beispielsweise eine drahtlose Kopplung von Hörgeräten notwendig.

In the following, it is illustrated by means of several examples how the spatial reproduction can be improved as a function of certain parameters of the hearing device or of the hearing device. For this purpose, the corresponding parameter is displayed and in each case specified how the spatial reproduction can be changed by changing one of the above-mentioned target variables:

1. 1. Classification of the input signal
   1. a) setting the method by means of a classifier
      • i) increase in distance depending on the signal type (eg music or speech); she lets herself be helped by the construction of FIG. 2 achieve, as already described above.
      • ii) stereo enhancement depending on the signal type (eg music or speech); it can be achieved with binaural supply by correspondingly different offset of the left and right signal.
      • iii) mixing Hall depending on the class; mixing and controlling using the classifier is similar to the principle of FIG. 2 carry out.
   2. b) Hall dependence (detection with the classifier or another suitable analysis unit)
      • i) increase in distance as a function of the relationship of the signal (for example, if the signal has faded, the distance extension should be smaller);
      • ii) increase in stereo power depending on the signal's relationship (eg, if the signal is lost, the stereo spread should be lower);
      • iii) admixture of Hall as a function of the Hall content detected in the signal
   3. c) Virtual auditory display
      • i) class-dependent displacement of a signal in a spatial direction (eg shifting of a noise backwards);
      • ii) Any combination of the method 1.ci with one or more methods of 1.a and / or 1.b
2. 2. Directional microphone or separated signals
   1. a) Direction filtering by means of a directional microphone and subsequent change in the source distance depending on the direction instead of a pure suppression (several directional characteristics would have to be calculated in parallel).
   2. b) Change in the source distance of signals obtained using a blind source separation (BSS) algorithm, depending on source direction and / or distance.
   3. c) combining the processes of 2.a and / or 2.b with one or more of the processes of 1.
3. 3. Externally fed signals
   In addition to the microphone or the other signals, for example, electromagnetically coupled into the hearing / the hearing aid. Different treatment of the microphone signals and the electrically supplied signals can lead to an improvement of the spatial reproduction. For example, the microphone signals could be further removed or faded backwards if an externally fed signal (telephone, stereo system, FM system, etc.) is present.
4. 4. Noise component of noise removal
   Instead of suppressing the interference component, it can be remixed to the signal in an adjustable distance or direction. This can also be done with a similar circuit structure, as in FIG. 2 is shown.
5. 5. level dependence
   According to a further additional or alternative option, the strength of the effectiveness of the methods is adjusted as a function of the signal level. This can be easily realized by a corresponding level meter, which is usually present anyway.
6. 6. User control
   According to another option, it may be provided that the user manually controls the effectiveness of the algorithms, for example by means of a remote control. This would allow manual or semi-automatic control.
7. 7. Binaural methods
   The parameters of the methods are set after analyzing the signals for the right and left ears. For this purpose, for example, a wireless coupling of hearing aids is necessary.

1. a) ein FIR-Filter 81 (finite impulse response) wie in dem Beispiel der FIG 3 und 4;
2. b) ein IIR-Filter 82 (infinite impulse response), das rekursiv ausgebildet ist;
3. c) eine Kreuzgliedstruktur 83, wodurch zwei Signale R, L durch kreuzweises Verknüpfen mit den Gewichten G1, G2, G12 und G21 zu Ausgangssignalen R_out und L_out werden;
4. d) ein zeitvariantes Filter 84, wodurch eine Zeitverschiebung des Signals erfolgt und
5. e) einen stochastischen Dekorrelator 85 zur Trennung von Störgeräuschen.

The processing block 8 for spatial processing (see FIG FIG. 2 ) can according to the example of FIG. 5 be realized in different ways. So this block can have one or more of the following elements:

1. a) a finite impulse response (FIR) filter 81 as in the example of FIG 3 and 4 ;
2. b) an infinite impulse response (IIR) filter 82 that is recursively constructed;
3. c) a cross-member structure 83, whereby two signals R, L are cross-linked to the weights G1, G2, G12 and G21 to output signals R _out and L _out ;
4. d) a time-varying filter 84, whereby a time shift of the signal takes place and
5. e) a stochastic decorrelator 85 for the separation of noise.

The above-described inventive method for improving the spatial perceptibility or the corresponding Hearing devices / hearing aids thus lead, for example, to improved sound perception. For example, music can sound more lively. In particular, the brain is supported by the deliberately controlled different localization of the sources to be able to better separate the "competing" sources.

Claims (13)

Method for the binaural supply of a human hearing by means of a binaural hearing device Recording an input signal of the hearing device, Processing the input signal into an output signal resulting in a spatial perception, and - Controlling at least one size of the output signal based on the input signal of the hearing device such that the spatial perception is changed. The method of claim 1, wherein the input signal is analyzed and the control is performed according to the analysis result. The method of claim 2, wherein the analyzing comprises determining the relationship of the input signal, and the controlling is according to the relationship. The method of claim 2 or 3, wherein the analyzing comprises separating sound sources, and the controlling is according to the separated sound sources. The method of claim 4, wherein the separating is performed by a directional microphone (13, 14) and / or a blind source separation algorithm. Method according to one of claims 2 to 5, wherein the analyzing comprises a noise detection, and the control is carried out according to the noise component. Method according to one of claims 2 to 5, wherein when analyzing a signal class or a level of the input signal is determined, and the control is carried out depending on the classification or the determined level. Method according to one of the preceding claims, wherein at least one externally fed in by the hearing device Signal is recorded next to a microphone signal, and the control is carried out according to the recorded signal. Method according to one of the preceding claims, wherein the size influencing the spatial perception is a distance of a source from the hearing device, a spatial direction of a source with respect to a predetermined zero-degree direction of the hearing device, a source location and / or a property of the room reverb. Hearing device for binaural care of a human hearing with a recording device (2) for recording an input signal of the hearing device, a processing means for generating an output signal resulting in a spatial perception on the basis of the input signal and - A control device (3) for controlling the processing device with respect to at least one size of the output signal of the hearing device such that the spatial perception is changed. Hearing apparatus according to claim 10, wherein the processing means comprises a classifier (6) whose classification result is fed to the control means (3) for control. Hearing apparatus according to claim 10 or 11, wherein the processing means for separating sources comprises a directional microphone and / or a blind source separation unit (7). Hearing apparatus according to one of claims 10 to 12, wherein the hearing device has a plurality of input channels and the control device (3) is controllable in dependence on the signal strength of one or more of the input channels.

Images