EP3110172A1 - Method for processing signals in a binaural hearing aid - Google Patents

Abstract

The invention specifies a method (20) for signal processing in a binaural hearing device (2) with a first hearing aid device (22) and a second hearing aid device (24), the first hearing aid device (22) having a first microphone for generating a first signal (26). and a first sound generator, wherein the second hearing aid (24) has a second microphone for generating a second signal (28) and a second sound generator, wherein based on the first signal (26) and the second signal (28) at least approximately one direction ( 30) of a main sound source (32) is determined, wherein in a deviation of the direction (30) of the main sound source (32) from a frontal direction (6) of the binaural hearing aid (2) each of the main sound source (32) closer located hearing aid (36) as a local hearing aid (36) and the main sound source (32) further remote hearing aid (38) are defined as remote hearing aid (38), wobe i) in the local hearing aid device (36) at least in one frequency band (39) the first signal (26) is filtered with at least one angle-dependent first filter factor (40), thereby producing a first filtered signal (42), on the basis of the first signal (26 ) and / or the second signal (28) and / or the direction (30) of the main sound source (32) an adaptation coefficient (44) is determined from the first signal (26) and the first filtered signal (42) Adjustment coefficients (44) a first adjusted signal (46) is generated, and from the first adjusted signal (46) and the second signal (28) a local directional characteristic (48) of a reproduced by the sound generator of the local hearing aid (36) reproduction signal (50 ) is determined.

Description

The invention relates to a method for signal processing in a binaural hearing aid having a first hearing aid and a second hearing aid, wherein the first hearing aid has a first microphone for generating a first signal and a first sound generator, and wherein the second hearing aid, a second microphone for generating a second microphone Having signal and a second sound generator.

A binaural hearing aid usually comprises one hearing aid per ear of the user, wherein in each of the two hearing aids are arranged in each case a microphone and an electro-acoustic transducer for generating sound. Due to their spacing, a directional characteristic can now be formed from the recording signals of the two microphones, with the directional characteristics in the respective output signal output to the electroacoustic transducer being different for both hearing aid devices in order to achieve better spatial perception. The term "microphone" used here and below is here understood as meaning both a single, then in particular substantially omnidirectional microphone, ie a single microphone, and a microphone which comprises a plurality of individual microphones, in particular two single microphones, and which such by interconnecting the single microphones already has a directional characteristic, that is a directional microphone. In other words, in the latter case, a hearing aid then has a monaural directional microphone system.

In a conversation situation with several interlocutors, which surrounds the user of a hearing aid in different directions, with a noticeable noise level in the environment adjusting the binaural directional characteristic can help to isolate the voice signals of individual interlocutors and thus for the user of the binaural hearing aid understanding of Speech signal, which comes from a specific target caller to improve. Interfering noise in the vicinity of the target call partner can be reduced as well as conversational contributions of other call partners, if they are not identified for the moment as the relevant useful signal. This is achieved in that the directional characteristic is aligned in a comparatively narrow angular range, for example with a total angular aperture of 90 degrees or even only 45 degrees, in the frontal direction of the user.

Usually, for an adaptation of the binaural directional characteristic a precise knowledge of the position of the target sound source or the target call partner, or equivalent to this, the exact direction required from which the useful signal comes. For the operation of hearing aids this is usually assumed that the position of the target sound source is located in the frontal direction, ie approximately 0 degrees with respect to the viewing direction of the user. A binocular directional characteristic oriented at 0 degrees with an angle apparture of 90 degrees or even only 45 degrees now suppresses a large part of the background noise, which initially improves the signal-to-noise ratio for the useful signal originating from the target call partner. Furthermore, voice signals of other call partners outside of the angular range, in which the directional characteristic has a high sensitivity to noise, are correspondingly suppressed. Such a listening situation, which is generally referred to as a "cocktail party situation", can always result for a user of a hearing device when a conversation is to be conducted in the presence of other persons who are themselves talking to one another.

In a normal conversation situation, both the caller makes small movements, which in an angular range of up to 10 or even up to 20 Degree can lie. Likewise, the user of the binaural hearing aid can perform by his gestures in conversation natural head movements, which can lead to similar angular deviations of his frontal direction with respect to the interlocutor. Due to these movements, the voice signal of the call partner can be appreciably attenuated in the conversation due to the narrow angular range of the directional characteristic. Since, in particular, head movements of the user of the binaural hearing device during a conversation situation are often barely perceptible to the user himself, and thus fluctuations in the signal level of the binaural hearing device are correspondingly short-term, the perception of hearing by the user can be significantly impaired, and in particular due to the Fluctuations in the sound level required higher concentration even be perceived as unpleasant.

From the DE 10 2013 207 149 A1 is a hearing aid system with at least two hearing aids known and a method for its operation known. The hearing aid system comprises in particular a signal processing device for processing audio signals and a signal connection for transmitting a first audio signal from each hearing aid to the signal processing device. The signal processing device evaluates a signal component from the preferred direction with respect to the head of the carrier in the first audio signals, wherein the signal processing device generates a first binaural directional microphone signal with the first audio signals and adjusts its directional characteristic as a function of the evaluation. It is thereby avoided to suppress other useful signals, for example spoken contributions from a round of talks.

In the EP 2 928 210 A1 For example, a binaural hearing system comprising left and right hearing aids, with noise suppression, and a user interface is proposed. The left and right hearing aid devices include at least two input units providing a representation of an input signal in the time domain in a number of frequency bands and time instances, and a noise cancellation system having a multi-channel "beamformer" connected to the input units and a directional one Signal generated. The wearer of the hearing system can specify a directivity with respect to a target signal via the user interface.

The invention has for its object to provide a method for a binaural hearing aid, which prevents as quickly and efficiently as possible in a hearing situation with a main sound source against a background noise noise fluctuations in the signal level due to relative movements of the main sound source to a user of the binaural hearing aid.

The above object is achieved by a method for signal processing in a binaural hearing aid with a first hearing aid and a second hearing aid, wherein the first hearing aid has a first microphone for generating a first signal and a first sound generator, wherein the second hearing aid a second microphone for Generation of a second signal and a second sound generator, wherein at least approximately a direction of a main sound source is determined based on the first signal and the second signal, wherein in a deviation of the direction of the main sound source from a frontal direction of the binaural hearing the respective main Sound source closer hearing aid as a local hearing aid and the main sound source farther away hearing aid are defined as remote hearing aid.

It is provided that in the local hearing aid at least in a frequency band, the first signal with at least a first angle-dependent filter, ie using an angle-dependent filter factor, filtered, and thereby a filtered first signal is generated, based on the first signal and / or the second Signal and / or the direction of the main sound source is determined a matching coefficient, from the first signal and the filtered first signal on the basis of the adaptation coefficient, an adapted first signal is generated, and from the adjusted first signal and the second signal, a local directivity of one through the Sound generator of the local hearing aid to be output reproduced signal is determined. Advantageous and partly in itself inventive embodiments are the subject of the dependent claims and the following description.

An at least approximate determination of the direction of the main sound source is to be understood here in particular as meaning that a plurality of angular ranges is determined or specified, and it is determined which of the angular ranges is to be assigned the direction of the main sound source. In particular, for this purpose, one of the angular ranges of the frontal direction of the binaural hearing device can be assigned, and thus comprise a zero angle of the angular scale, which is the basis of the division into the angular ranges. A deviation of the direction of the main sound source from the frontal direction of the binaural hearing aid in this case can be done by assigning the direction of the main sound source to a different angle range than that of the frontal direction. In this case, the frontal direction of the binaural hearing device is preferably to be defined via the plane of symmetry of the two hearing aid devices during operation when properly worn by the user.

In particular, in this case also a frontal angular range and a right or left deviation range can be defined, so that the approximate determination of the direction of the main sound source in this case means to assign the main sound source either the frontal angular range or one of the two deviation ranges. Filtering the first signal with at least one angle-dependent first filter factor comprises, in particular, multiplying the first signal in a respective frequency band by an angle-dependent first filter factor. Likewise, however, the first signal may also be convolved with a vector-valued filter factor in the time domain or in the frequency domain to produce the first filtered signal.

For the determination of the adaptation coefficient in a frequency band, the first signal is to be assigned to either the local hearing aid or the remote hearing aid, and the second signal to be assigned to the then remaining hearing aid. The adaptation coefficient in a local hearing aid indicates whether and, if appropriate, to what extent in the local hearing aid the first signal the second signal is to be adjusted by generating the first adjusted signal from the first signal and the first filtered signal. For this purpose, the first adjusted signal is formed, for example, by a mixture of the first signal and the first filtered signal, for example in the form of a weighted sum. In particular, the first adjusted signal will be formed by a convex sum of the first signal and the first filtered signal with the adaptation coefficient as the convexity parameter. The adaptation coefficient in this case is between 0 and 1, wherein for a value of 1, corresponding to a complete adaptation of the first signal, the first filtered signal is passed on directly, while for a value of 0 no adaptation takes place.

The angle-dependent first filter factor, with which the first signal is filtered to produce the first filtered signal, takes into account the fact that in the case of a deviation of the direction of the main sound source from the frontal direction on the one hand, a minimum, due to the transit time difference time shift occurs between the first signal and the second signal. This shift can initially be approximated as a phase shift. Moreover, on the other hand, in the case of the angular deviation caused by the head of the user of the binaural hearing aid, shadowing effects occur, as a result of which the remote hearing aid device has a weaker signal level. By filtering the first signal with the first filter factor, the phase difference and the volume differences between the first signal and the second signal for the direction of the main sound source are compensated, thereby first for the further signal processing in the local hearing aid due to the equalized level and the aligned phase in the first Signal and in the second signal the main sound source can be considered as a frontal source.

In a hearing situation of the user of the binaural hearing aid, in which a voice signal of a conversation partner should be reproduced as clearly as possible while suppressing background noise like other speech signals, the binaural directional pattern is usually very narrow towards the front aligned to the unwanted sound signals through the lower Sonic sensitivity in those directions, which did not consider that as a useful signal Speech signal of the interlocutor correspond to reduce. Characterized in that now the binaural directional characteristic, that is, the directional characteristic formed by signal components of the two microphones in the playback signal each one of the sound generator, based on the first adjusted signal and the second signal is formed, and in the two said signals defakto the directional deviation of the main sound source has been corrected from the frontal direction, a voice signal of a conversation partner in relative movements of the interlocutor with respect to the user of the binaural hearing aid is no longer mitigated by the narrow binaural radiation pattern.

In such relative movements, as may arise from short-term head movements of the user of the binaural hearing aid or by spontaneous gestures of the interlocutor, is simply said the other party by the adaptation of the first signal to the second signal always "retrieved" in the frontal direction. A particular advantage here lies in the fact that the adaptation of the first signal to the second signal, by which the effects of the relative movements between the user and a call partner are corrected, can take place independently of the formation of the binaural directional characteristic, and thus does not affect their algorithm.

Optionally, after the formation of the binaural directional characteristic in the local hearing aid from the first adjusted signal and the second signal, the playback signal still nachzubearbeiten accordingly to achieve the most realistic spatial perception of the signal of the main sound source.

Preferably, the approximate direction of the main sound source and / or the adaptation coefficient in at least one frequency band are determined based on the signal levels of the first signal and the second signal. In particular, this can be frequency bandwise, with only a subset of frequency bands being used for the final determination of the direction of the main sound source. A direction determination based on the differences in the level of the first signal and the second signal can be realized particularly easily and quickly. In particular, the signal level of the sum of the first Signal and the second signal can be used, if necessary, to be able to take into account phase cancellation effects.

Alternatively, in at least one frequency band, the value of an angle-dependent second filter factor may be selected for at least a left deviation angle, a zero angle and a right deviation angle, from the first signal and the second signal, a signal to be multiplied for alignment with the second filter factor is, whereby in each case an aligned signal is generated, from the difference of the aligned signal and the other signal, an angle-dependent interference power are determined, and from the sum of the aligned signal and the other signal, an angle-dependent overall performance are determined from the angle-dependent interference power and A normalized angle-dependent interference power can be determined for the angle-dependent overall power, and based on a comparison of the normalized angle-dependent interference powers at least for the left-hand deviation angle, zero angle and the right deviation angle, the approximate direction of the main sound source and / or an adjustment coefficient are determined.

• In dem das ausgewählte Signal mit dem zweiten Filterfaktor -jeweils wenigstens für den linken Abweichungswinkel, den Nullwinkel und den rechten Abweichungswinkel - multipliziert wird, wird es entlang des jeweils des anderen Signals ausgerichtet. Diese Ausrichtung erfolgt dabei derart, dass für denjenigen Winkel, welcher als Parameter in den winkelabhängigen zweiten Filterfaktor eingeht, die beiden Signale keinen nennenswerten Phasen- und Lautstärkeunterschiede aufweisen. Bildet man nun aus dem ausgerichteten Signal und dem jeweils anderen Signal die Differenz, so wird ein Schallsignal aus derjenigen Richtung, welche als Winkelparameter in den zweiten Filterfaktor eingeht, näherungsweise ausgelöscht. Für diesen Winkel liegt die winkelabhängige Interferenzleistung nahe Null.

The specification of the second filter factor for a left deviation angle, a zero angle and a right deviation angle corresponds to the division of the space into three angular ranges, wherein the direction of the main sound source is approximately determined by an arrangement in one of the three angular ranges. This classification is now carried out as follows:

• By multiplying the selected signal by the second filter factor, at least for the left deviation angle, the zero angle and the right deviation angle, respectively, it is aligned along the respective other signal. This alignment takes place in such a way that for the angle which enters into the angle-dependent second filter factor as a parameter, the two signals have no appreciable phase and volume differences. If one then forms the difference from the aligned signal and the respective other signal, then a sound signal from that direction, which becomes as Angular parameter enters the second filter factor, approximately extinguished. For this angle, the angle-dependent interference power is close to zero.

In order to be able to compare the angle-dependent interference power for the three angular ranges mentioned above, it is necessary to normalize this beforehand over the total power which is formed by the sum signal from the adapted signal and the respective other signal. The angle-dependent interference power and the angle-dependent overall power are preferably to be calculated as an absolute value or absolute square of the difference or the sum of the aligned signal and the respective other signal.

The direction of a main sound source can then be identified as the direction in which the normalized angle-dependent interference power is minimal. A priori, this can also be done for several angular ranges than three, however, for most applications, a distinction between the frontal region and two left- or right-symmetrically distributed deviation ranges is sufficient.

It proves to be further advantageous here if a frequency band-dependent direction parameter is determined in each case in a plurality of frequency bands based on the comparison of the normalized angle-dependent interference powers at least for the left deviation angle, the zero angle and the right deviation angle, the approximate direction of the main sound source is determined from the frequency band-dependent directional parameters. This can be done for example by an optionally weighted average of the directional parameters. Preferably, the determination of the direction of the main sound source is performed only in those frequency bands in which a significant directional dependence of the sound signal of the main sound source is to be expected. By using directional parameters from several frequency bands, errors in the direction determination, which can arise due to fluctuations for example, can be compensated or minimized.

In this case, the first filter factor for generating the first filtered signal and the second filter factor preferably have the same frequency dependence with respect to the respective frequency band and the same angle dependence at least for the left deviation angle, the zero angle and the right deviation angle. This means that to adapt the first signal to the second signal, ie for angle-dependent alignment, filter factors with the same functional dependence are used as for determining the direction of the main sound source.

In an advantageous embodiment of the invention in the local hearing aid in a plurality of frequency bands respectively a first filtered signal and based on this a first adjusted signal is generated, with increasing frequency of the frequency band for generating the first filtered signal for the first filter factor of the angle in the direction of Main sound source increases monotonically. A monotonic increase includes, in particular, that the angle used for the first filter factor can be chosen to be constant for a plurality of consecutive frequency bands, with a smaller angle selected for the group of low frequency bands for the first filter factor, and for a group higher frequency bands select a larger angle for the first filter factor. This takes into account the fact that the directional dependence of signal components in lower frequency bands is usually lower, so that the need for an angle-dependent adaptation is not as significant here as in higher frequency bands, in which conventional useful signal components have a significantly higher directional dependence, which is preferred should be worn.

Expediently, the first filter factor is in each case of the magnitude .ltoreq.1. This is particularly favorable in the case where the first signal, which is to be adapted to the second signal by means of the first filter factor, is formed by the signal of the local hearing aid. The signal recorded by the microphone of the remote hearing aid has a lower volume level due to shadowing effects by the user's head. This is done by a represents the first filter factor whose amount ≤ 1 is selected. The first filtered signal is not boosted by the filtering process. The selection of whether to select the signal of the microphone of the local hearing aid or the signal of the microphone of the removed hearing aid as the first signal to be adapted to the second signal may be made particularly dependent on the current hearing situation. Especially in a noisy environment, it is preferable to adapt the "local signal" to the "distant signal" since, in this case, the level of the signal is not further increased by the adaptation process, whereby supersaturation can be avoided.

It proves to be further advantageous if a compensation of a volume and a phase difference is made in the playback signal of the local hearing aid on the basis of the first angle-dependent filter factor and / or the adaptation coefficient, if the first signal is generated by the microphone of the local hearing aid. In this case of adaptation, the local hearing aid will effectively provide the "local signal" with the phase and volume reference of the remote hearing aid. For the playback signal of the local hearing aid, this referencing to the remote hearing aid is to be compensated in order to obtain the most realistic possible spatial perception of the user of the hearing aid.

The invention further mentions a binaural hearing device having a first hearing aid device and a second hearing aid device, wherein the first hearing aid device has a first microphone for generating a first signal and a first sound generator, the second hearing aid device having a second microphone of a second signal and a second sound generator, and at least one signal processing unit configured to perform the above-described method. The advantages mentioned for the method and its developments can hereby be transferred mutatis mutandis to the binaural hearing aid.

Fig. 1 a-c

in einer Draufsicht einen Benutzer eines binauralen Hörgerätes in einer Gesprächssituation mit einem Gesprächspartner,

Fig. 2

in einem Blockdiagram den Ablauf eines Verfahrens zur richtungsabhängigen Anpassung des Signale in einem binauralen Hörgerät für die Gesprächssituation nach Fig. 1,

Fig. 3

in einem Blockdiagramm eine weitere Ausgestaltung des Verfahrens nach Fig. 2,

Fig. 4

in einem Blockdiagramm die näherungsweise Bestimmung der Richtung eines Gesprächspartners über eine winkelabhängige Interferenzleistung, und

Fig.5a-c

in einer Draufsicht angepasste Richtcharakteristiken eines binauralen Hörgeräts in der Gesprächssituation nach Fig. 1 a-c.

An embodiment of the invention will be explained in more detail with reference to a drawing. Here are shown schematically in each case:

Fig. 1 ac

in a plan view a user of a binaural hearing aid in a conversation with a conversation partner,

Fig. 2

in a block diagram the sequence of a method for direction-dependent adaptation of the signals in a binaural hearing aid for the conversation situation Fig. 1 .

Fig. 3

in a block diagram, a further embodiment of the method according to Fig. 2 .

Fig. 4

in a block diagram, the approximation of the direction of a call partner on an angle-dependent interference power, and

5a-c

In a plan view adapted directional characteristics of a binaural hearing aid in the conversation situation Fig. 1 ac ,

Corresponding parts and sizes are provided in all figures with the same reference numerals.

The influence of the movements of a user of the binaural hearing aid in a conversation, or the movements of his interlocutor on the signal level of the speech signal of the interlocutor is in FIGS. 1a to 1c shown. FIG. 1 a shows a user 1 of a binaural hearing device 2 who is in a conversation with a conversation partner 4. The interlocutor 4 is positioned in the frontal direction 6 of the user 1. As a result of the narrow directional characteristic 8 of the binaural hearing aid objections of other interlocutors 10 to 13 of user 1 are barely perceived. In Figure 1 b the main interlocutor 4 of the user 1 has slightly moved aside, for example, as a result of a relief movement. If now the user 1 of the movement of the interlocutor 4 does not follow directly with a change in his line of sight, but only with his eyes, this has the consequence that the speech signal of the main interlocutor 4 due to its shift within the directional characteristic 8 of the binaural hearing aid 2 is slightly attenuated. Something similar happens in Figure 1 c in which the user 1 slightly turns his line of sight while the main interlocutor 4 keeps his position. Again, the consequence is that due to the relative movement of the main interlocutor 4 is no longer positioned in the center of the directional characteristic 8, so that his voice signal undergoes attenuation.

In FIG. 2 schematically the flow of a method 20 for signal processing in a binaural hearing aid 2 is shown in a block diagram. The binaural hearing device 2 comprises a first hearing aid device 22 and a second hearing aid device 24, each of which includes a microphone, not shown in the drawing. The microphone of the first hearing aid 22 generates a first signal 26 from sound, the microphone of the second hearing aid 24 correspondingly generates a second signal 28. Based on the first signal 26 and the second signal 28, it can be determined in a direction detection 30 that the call partner 4 of the User 1 which here forms the main sound source 32, is not aligned in the frontal direction 6 of the user 1 but with respect to this has a certain angular deviation 34. As a result of this angular deviation 34, the second hearing aid device 24 closer to the interlocutor 4 is defined as a local hearing aid device 36, while the first hearing aid device 22 further from the interlocutor 4 is defined as a remote hearing aid device 38. In the individual frequency bands 39, the first signal 26 is multiplied by a first filter factor 40 in the local hearing aid device 36, whereby a first filtered signal 42 is first generated.

In the direction detection 30, an adaptation coefficient 44 is determined on the basis of the direction of the conversation partner 4, and then a first adapted signal 46 is generated from the first signal 26, the first filtered signal 42 and the adaptation coefficient 44. The first adjusted signal 46 is formed, for example, as a weighted superposition of the first filtered signal 42 and the first signal 26, wherein the adjustment coefficient 44 is used for weighting. The first adjusted signal 46 and the second signal 28 are now used to form the directional characteristic 48, which the reproduced signal 50 to be outputted via the sound generator of the local hearing aid 36 has to be exhibited in the respective frequency band.

In FIG. 3 is an alternative embodiment of the method 20 according to FIG. 2 shown. In this case, the local hearing aid device 36 is assigned to the first hearing aid device 22, while the remote hearing aid device 38 is to be assigned to the second hearing aid device 24. Here, too, the first signal 26 is adapted to the second signal 28 by multiplying the first signal 26 by a first filter factor 40, whereby a filtered first signal 42 is generated, which by means of the adaptation coefficient 40, which in the direction detection 30th determined, is used to form the first matched signal 46. This first adjusted signal 46 now enters the forming directivity 48 with the second signal 28 as an input variable. Since the local hearing aid device 36, which is closer to the interlocutor 4 of the user 1, has been selected, the adaptation of the first signal 26 with respect to the reference of the remote hearing aid device 38 is effected by means of the adaptation coefficient 44 and the first filter factor 40 on the reproduction signal 50 a compensation 52 of the volume and the phase difference in order to restore the spatial perception as possible.

In Fig. 4 is shown in a block diagram an approximate direction determination 30 for the speech signal of a conversation partner not shown. For the space in front of the user 1 of the binaural hearing aid, a left deviation angle 56a, a zero angle 56b and a right deviation angle 56c are given, whereby the space in front of the user is divided into three angular ranges. For the left deviation angle 56a, the zero angle 56b and the right deviation angle 56c angle-dependent second filter parameters 40a, 40b, 40c are respectively predetermined in a frequency band 39. These can in this case have the same angular dependence in the respective frequency band 39 as the first filter parameter 40. From the first signal 26 and the second signal 28 one, in this case the first signal 26 is selected, which aligns with the other one, ie here with the second signal 28 is.

For this purpose, first the first signal 26 for each of said angles 56a, 56b, 56c is multiplied by the respective second filter parameter 40a, 40b, 40c, whereby an angle-dependent aligned signal 60a, 60b, 60c is formed in each case. For each of the aforementioned angles 56a, 56b, 56c, an angle-dependent interference power 62a, 62b, 62c and an angle-dependent overall power 64a, 64b, 64c are now formed from the aligned signal 60a, 60b, 60c with the second signal by difference or summation. The angle-dependent interference power 62a, 62b, 62c is respectively normalized by dividing the associated total angularly-dependent power 64a, 64b, 64c thereover, whereby for each of the angles 56a, 56b, 56c a normalized angle-dependent interference power 66a is obtained from the first signal 26 and the second signal 28 , 66b, 66c.

The normalized angle-dependent interference powers 66a, 66b, 66c are now compared with each other. The orientation of the first signal 26 on the second signal 28 is such that a sound, which respectively comes from the direction of the angle used for the alignment 56a, 56b, 56c, due to the difference formation leads to no significant angle-dependent interference power 62a, 62b, 62c. Therefore, a direction parameter 68, which is used for approximate direction determination for the speech signal of the interlocutor, can be determined from the angle of left deviation angle 56a, zero angle 56b and right deviation angle 56c, for which the normalized angle-dependent interference power 66a, 66b, 66c is minimal. The direction parameter 68 can be used in the relevant frequency band on the one hand directly to determine the adaptation coefficient 44, and on the other direction direction parameters 68 of multiple frequency bands 39 are averaged to use this, the voice signal of the caller, which represents the main sound signal for the user 1, one of the three attributed angle.

In Fig. 5a-c is in a top view in each case the conversation situation Fig. 1 ac and the adjustments of the directional characteristics 8, 48 to the movements of the Interlocutor 4 or shown to the movements of the user 1. In Fig. 5a is the conversation partner 4 head-on to the user, an adjustment of the directional characteristics 8 is not necessary. Fin Fig. 5b has the interlocutor 4 a slight sideways movement completed. The local directional characteristic 48 of the local hearing aid 36 follows this movement, while the directional characteristic 8 of the remote hearing aid 38 remains aligned in the frontal direction 6. As a result, the speech signal of the call partner is still well detected by the local directional characteristic 48, while due to the shift with respect to the directional characteristic 8 of the remote hearing aid 38 in the playback signal, the speech signal is attenuated. A similar situation shows Fig. 5c in which now the user 1 has slightly rotated his frontal direction 6 with respect to the interlocutor 4. However, the local directional characteristic 48 of the local hearing aid does not follow this rotation, but rather remains aligned with the interlocutor 4, so that the voice signal thereof does not recover any attenuation in the playback signal of the local hearing aid 36.

Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by this embodiment. Other variations can be deduced therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1

user

2

binaural hearing aid

4

interlocutor

6

frontal direction

8th

directivity

10-13

interlocutor

20

method

22

first hearing aid

24

second hearing aid

26

first signal

28

second signal

30

direction recognition

32

Main sound source

34

angular deviation

36

local hearing aid

38

remote hearing aid

39

frequency band

40

first filter factor

40a-c

second filter factor

42

first filtered signal

44

adjustment coefficient

46

first adjusted signal

48

local directional characteristic

50

Playback signal

52

compensation

56a

left deviation angle

56b

zero angle

56c

right deviation angle

60a-c

aligned signal

62a-c

angle-dependent interference power

64a-c

angle-dependent overall performance

66a-c

standardized angle-dependent interference power

68

directional parameters

Claims (9)

Method (20) for signal processing in a binaural hearing aid (2) having a first hearing aid device (22) and a second hearing aid device (24), wherein the first hearing aid device (22) comprises a first microphone for generating a first signal (26) and a first sound generator wherein the second hearing aid device (24) has a second microphone for generating a second signal (28) and a second sound generator,
wherein on the basis of the first signal (26) and the second signal (28) at least approximately a direction (30) of a main sound source (32) is determined, wherein in a deviation of the direction (30) of the main sound source (32) of a Frontalrichtung (6) of the binaural hearing aid (2) each of the main sound source (32) closer hearing aid device (36) as a local hearing aid (36) and the main sound source (32) further remote hearing aid (38) as a remote hearing aid (38) are defined
wherein in the local hearing aid device (36) at least in one frequency band (39) - the first signal (26) is filtered with at least one angle-dependent first filter factor (40), and thereby a first filtered signal (42) is generated, an adaptation coefficient (44) is determined on the basis of the first signal (26) and / or the second signal (28) and / or the direction (30) of the main sound source (32), - from the first signal (26) and the first filtered signal (42) based on the adaptation coefficient (44), a first adjusted signal (46) is generated, and a local directional characteristic (48) of a reproduction signal (50) to be output by the sound generator of the local hearing aid (36) is determined from the first adjusted signal (46) and the second signal (28). Method (20) according to claim 1,
wherein the approximate direction of the main sound source (32) and / or the adaptation coefficient (44) in at least one frequency band (39) is determined from the signal levels of the first signal (26) and the second signal (28). Method (20) according to claim 1,
wherein in at least one frequency band (39) the value of an angle-dependent second filter factor (40a-c) is specified for at least a left deviation angle (56a), a zero angle (56b) and a right deviation angle (56c), a signal is selected from the first signal (26) and the second signal (28) which is to be multiplied for alignment with the second filter factor (40a-c), whereby an aligned signal (60a-c) is generated in each case, - An angle-dependent interference power (62a-c) is determined from the difference of the aligned signal (60a-c) and the respective other signal (28), and from the sum of the aligned signal (60a-c) and the respective other signal (28 ) an angle-dependent total power (64a-c) is determined, a normalized angle-dependent interference power (66a-c) is determined from the angle-dependent interference power (62a-c) and the angle-dependent overall power (64a-c), based on a comparison of the normalized angle-dependent interference powers (66a-c) for at least the left deviation angle (56a), the zero angle (56b) and the right deviation angle (56c) the approximate direction of the main sound source (32) and / or an adaptation coefficient ( 44) is determined. Method (20) according to claim 3,
wherein at least for the left deviation angle (56a), the zero angle (56b) and the right deviation angle (56c), a frequency band-dependent direction parameter (68 ), and
wherein the approximate direction of the main sound source (32) is determined from the frequency band dependent directional parameters (68). Method (20) according to claim 3 or claim 4,
wherein the first filter factor (40) for generating the first filtered signal (42) and the second filter factor (40a-c) have the same frequency dependence with respect to the respective frequency band (39), and at least the left deviation angle (56a), the zero angle (56b ) and the right deviation angle (56c) have the same angular dependence. Method (20) according to one of the preceding claims,
wherein in the local hearing aid (36) in a plurality of frequency bands (39) in each case a first filtered signal (42) and based on this a first adjusted signal (46) is generated, and
wherein with increasing frequency of the frequency band (39) for generating the first filtered signal for the first filter factor (40), the angle in the direction of the main sound source (32) in each case increases monotonically. Method (20) according to one of the preceding claims,
wherein the first filter factor (40) is each of the amount ≤ 1. Method (20) according to one of the preceding claims,
wherein in the playback signal (50) of the local hearing aid (36) based on the first filter factor (40) and / or the adjustment coefficient (44) a compensation (52) of a volume and a phase difference is made when the first signal (26) through the microphone the local hearing aid (36) is generated. Binaural hearing aid (2) having a first hearing aid device (22) and a second hearing aid device (24), wherein the first hearing aid device (22) has a first microphone for generating a first signal (26) and a first sound generator, wherein the second hearing aid device (24 ) comprises a second microphone for generating a second signal (28) and a second sound generator, and at least one signal processing unit which is adapted to perform the method (20) according to one of the preceding claims.

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