METHOD FOR OPERATING A HEARING AID AND HEARING AID

Abstract

A method for operating a hearing aid includes providing the hearing aid with an ANC unit and a speech recognition unit. The ANC unit is configured to process multiple frequency ranges and at the same time to suppress noises from the surroundings in each of these frequency ranges using a respectively settable ANC strength. The speech recognition unit recognizes for each of the frequency ranges whether or not speech is present therein. The ANC unit is controlled in such a way that the ANC strength is set for a respective frequency range depending on whether or not the speech recognition unit has recognized speech in that frequency range. A hearing aid having a control unit configured to execute the method is also provided.

Claims

1. A method for operating a hearing aid, the method comprising: a) providing a hearing aid having an ANC unit and a speech recognition unit; b) using the ANC unit to process multiple frequency ranges and to thereby suppress noises from the surroundings in each of the frequency ranges by using a respectively settable ANC strength; c) using the speech recognition unit to recognize whether or not speech is present in each of the frequency ranges; and d) controlling the ANC unit to set the ANC strength for a respective frequency range in dependence on whether or not the speech recognition unit has recognized speech in the respective frequency range.

2. The method according to claim 1, which further comprises upon a presence of speech in a respective frequency range, setting the ANC strength lower than when no speech is present in the respective frequency range, in order to suppress speech less than other noises.

3. The method according to claim 1, which further comprises recognizing only external speech not originating from a user of the hearing aid himself or herself as speech by the speech recognition unit.

4. The method according to claim 1, which further comprises providing the speech recognition unit with a Wiener filter for each of the frequency ranges, for recognizing speech.

5. The method according to claim 1, which further comprises providing the hearing aid with a filter bank having multiple channels each being associated with a respective one of the frequency ranges.

6. The method according to claim 1, which further comprises using the ANC unit to suppress noises only in frequency ranges below a limiting frequency.

7. The method according to claim 6, which further comprises selecting the limiting frequency as 1 kHz.

8. The method according to claim 1, which further comprises using the speech recognition unit to output a discrete measure for each of the frequency ranges for a presence of speech, causing the respective ANC strength to be switched between only two values.

9. The method according to claim 1, which further comprises using the speech recognition unit to output a continuous measure for each of the frequency ranges for a presence of speech, causing the ANC strength to be set continuously.

10. The method according to claim 1, which further comprises: providing the hearing aid with a signal processing unit to amplify each of the frequency ranges using a settable amplification; and setting the amplification higher in a respective frequency range upon a presence of speech than when no speech is present, causing speech to be amplified more than other noises.

11. A hearing aid, comprising a control unit configured to execute the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0039] FIG. 1 is a diagrammatic, plan view of a hearing aid;

[0040] FIG. 2 is a schematic and block circuit diagram of the hearing aid of FIG. 1; and

[0041] FIG. 3 is a diagram showing an overall spectrum having multiple frequency ranges.

DETAILED DESCRIPTION OF THE INVENTION

[0042] Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a hearing aid 2, having an earpiece 4, a receiver 6, at least one external microphone 8, although two external microphones 8 are provided in this case by way of example, a housing 10, and a control unit 12. FIG. 2 shows the hearing aid 2 and its interconnection more precisely and in a different view, wherein only one of the two external microphones 8 is shown, however. In addition, FIG. 2 shows an auditory canal 14 of a user of the hearing aid 2 and two paths P1, P2, through which noises V, N from the surroundings can enter the auditory canal 14. Noises V, N enter the auditory canal 14 along the path P1, through the hearing aid 2, namely in that the noises V, N are recorded by using the microphone 8 and output through the receiver 6. Electrical processing takes place in the hearing aid 2 in this case. In contrast, along the path P2, noises V, N enter the auditory canal solely acoustically past the hearing aid 2 and especially past the earpiece 4. Electrical processing does not take place in this case. However, depending on the ambient conditions, for example, the shape of the ear or the seat of the earpiece and the like, a transmission function (not explicitly shown) results, by which the noises V, N are modified along the path P2.

[0043] During the intended use of the hearing aid, for example, as shown in FIG. 2, the user wears the hearing aid 2 in or on the ear. In the case of the hearing aid type shown herein, the user wears the housing 10 on the ear, more precisely behind the ear, and the earpiece 4 in the ear. The concepts described herein are also similarly applicable to other hearing aid types. A method for operating the hearing aid 2 is also described hereinafter on the basis of the figures, especially during the intended use of the hearing aid 2. The control unit 12 is configured in the present case to execute the method.

[0044] The hearing aid 2 is used in general to output noises to the user of the hearing aid 2 and especially in this case to compensate for a hearing deficit of the hearing-impaired user in this case. The hearing aid 2 has at least one microphone 8, which records the noises V, N from the surroundings, also referred to as ambient noises or ambient sound. The microphone 8 is a so-called external microphone 8 in this case, thus it faces outward with respect to the auditory canal 14 and in particular not into it. The microphone 8 converts the noises V, N into an input signal E, which is an electrical signal. The input signal E is processed by the control unit 12 of the hearing aid 2 as needed and finally supplied to the receiver 6, which converts the input signal E into sound, for output to the user.

[0045] The hearing aid 2 has an ANC unit 16, wherein ANC is understood to mean active noise suppression, also referred to as “active noise cancellation.” The ANC unit 16 is a part of the control unit 12 in this case. The ANC unit 16 is configured, as shown in FIG. 3, to process multiple frequency ranges f1-f4 and at the same time to suppress noises V, N from the surroundings in each of these frequency ranges f1-f4 using a respectively settable ANC strength A. An example of the ANC strength A as a function of the frequency f is shown in FIG. 3. The ANC strength A is individually settable for each frequency range f1-f4. In FIG. 3, the ANC strength is greater in the frequency range f1 than in the frequency range f2 and is greater therein than in the frequency ranges f3, f4, in which the ANC strength A is equal.

[0046] The noises V, N from the surroundings regularly include, depending on the surrounding situation, interference noises N or useful noises or even both and regularly also speech V, which is typically a useful noise. The input signal E is supplied to the ANC unit 16 in the exemplary embodiment shown, either entirely or partially, but at least the frequency ranges f1-f4, which are then processed by the ANC unit 16. If still further frequency ranges f5, f6 are supplied, these are not necessarily processed, but are left unconsidered, for example. The ANC unit 16 analyzes the input signal E and outputs a feedforward signal Sff as a result thereof, for suppressing the noises V, N from the surroundings. Those noises V, N which penetrate during intended use from the outside and past the earpiece 4 into the auditory canal 14 are suppressed. The feedforward signal Sff is an electrical signal, which is supplied to the receiver 6 and is converted thereby into sound, which in turn entirely or partially extinguishes, i.e., suppresses, the noises V, N upon superposition in the auditory canal. Actual noise suppression takes place solely acoustically in this case and in particular not on an electrical level.

[0047] The ANC strength A specifies how strongly noises V, N are suppressed in the respective frequency range f1-f4. For example, the ANC strength A corresponds to an amplitude of the feedback signal Sff or an amplification factor, using which the feedback signal Sff is scaled in the ANC unit 16. The ANC strength A is accordingly a measure of the suppression of noises in the respective frequency range f1-f4. The greater the ANC strength A is, the stronger the suppression is. Vice versa, only minor suppression takes place at low ANC strength A. A complete deactivation of the ANC unit 16 for one or more frequency ranges f1-f4 is also possible, so that then no suppression of noises takes place in these ranges, the ANC strength A is then more or less “0.”

[0048] Furthermore, the hearing aid 2 has a speech recognition unit 18, for recognizing speech. The speech recognition unit 18 in the exemplary embodiment shown is a part of the control unit 12. The speech recognition unit 18 recognizes for each of the frequency ranges f1-f4 whether or not speech V is present therein. For this purpose, the input signal E is supplied to the speech recognition unit 18 in the present case, either entirely or partially, but at least the frequency ranges f1-f4, which are then processed by the speech recognition unit 18. If still further frequency ranges f5, f6 are supplied, these are not necessarily processed, but rather left unconsidered, for example. Alternatively or additionally, another input signal, which is generated, for example, by another, second microphone 8, is supplied to the speech recognition unit 18. In any case, the speech recognition unit 18 analyzes in the present case each of the frequency ranges f1-f4 separately, so that it is determined for each of these frequency ranges f1-f4 independently of the other frequency ranges f1-f4 whether or not speech V is present therein. The speech recognition unit 18 then outputs a signal S in the exemplary embodiment shown, which specifies for each of the frequency ranges f1-f4, whether or not speech V is present therein.

[0049] A core aspect in the present case is that the ANC unit 16 is controlled in such a way that the ANC strength A is set for a respective frequency range f1-f4 depending on whether or not the speech recognition unit 18 has recognized speech V in this frequency range f1-f4. In other words: the ANC unit 16 is controlled in a frequency-selective manner by using the speech recognition unit 18 to deliberately make the suppression of speech V by the ANC unit 16 different than for other noises N. In the exemplary embodiment shown, the setting of the ANC strength A by using the signal S is thus central and all other aspects are initially optional as such. The speech recognition unit 18 performs a differentiation between speech V and other noises, wherein this differentiation does not take place generally, but rather separately for each of the frequency ranges f1-f4, thus in a frequency-dependent manner. The differentiation is then used to select and set a respectively optimum ANC strength A for each of the frequency ranges f1-f4. If no speech V is contained in the noises from the surroundings, thus if speech V is not recognized in any of the frequency ranges f1-f4, the ANC unit 16 then operates in a normal operation and for this purpose uniformly on all frequency ranges f1-f4 and suppresses noises V, N in a more or less broadband manner, for example as illustrated in FIG. 3 by the sum of the horizontal solid lines in the frequency ranges f1-f4. The ANC strength A is set in this case, for example, in each frequency range f1-f4 depending on the amplitude of the noises V, N, so that sometimes different ANC strengths A result in normal operation in the various frequency ranges f1-f4, for example, as shown in FIG. 3.

[0050] In one advantageous embodiment (not explicitly shown), the hearing aid 2 has an interference noise detector as part of the control unit 12, which detector measures or estimates an amplitude of interference noises N, i.e., other noises N, in a respective frequency range f1-f4. The respective ANC strength A is then set depending on the amplitude of the interference noises N. Alternatively, for example, a predefined ANC strength A is simply set independently of interference noises N.

[0051] It is only when speech V is present in one or more frequency ranges f1-f4 and this is also recognized, that there is a deliberate deviation from the normal operation in these frequency ranges f1-f4 and the ANC strength A changes. For example, in FIG. 3, the speech recognition unit 18 has recognized speech V in the frequency range f3, whereupon the ANC strength A is reduced in this frequency range f3, for example, to the value shown in FIG. 3 by the horizontal, dashed line. The setting of the ANC strength A in reaction to the presence of speech V is also identified by using a vertical arrow in FIG. 3 for illustration. Even if still other noises N are present in a frequency range f1-f4 in addition to the speech V, which are in principle to be suppressed, the speech V is thus given priority in this case and the ANC strength A is set depending on the presence of speech V, even if this means that other noises N are then not suppressed or are at least suppressed less strongly.

[0052] A respective frequency range f1-f4 is a partial range of an overall spectrum G of frequencies, which are recorded by the hearing aid 2, processed as needed, and output. In FIG. 3, the first and lowermost six frequency ranges f1-f6 of an overall spectrum G (only partially shown) are shown by way of example. The overall spectrum G corresponds in this case to a part of the audible range and extends between a lower limit (not explicitly identified) and an upper limit (not explicitly shown), for example, 16 Hz to 20 Hz as the lower limit and 16 kHz to 20 kHz or less as the upper limit. In FIG. 3, the frequency ranges f1-f6 adjoin one another in pairs and do not overlap or only overlap slightly. In FIG. 3, the boundaries between two adjacent frequency ranges f1-f6 are indicated by a vertical dashed line, the boundary between the frequency ranges f4, f5 even by a double vertical dashed line. The frequency ranges f1-f6 each have a width B, which can be different in principle for each frequency range f1-f6. In the exemplary embodiment shown, however, all frequency ranges f1-f6 have the same width B, in the present case 250 Hz by way of example.

[0053] The term “frequency range f1-f6” is sometimes also used as a simplification to denote the “noises V, N in a frequency range f1-f6.”

[0054] In the exemplary embodiment shown, if speech V is present in a respective frequency range f1-f4, the ANC strength A is set lower than in comparison to cases in which no speech V is present in this frequency range f1-f4, so that speech V is suppressed less than other noises N. Speech V is thus deliberately excluded from the suppression by the ANC unit 16 or at least suppressed less considered relatively than other noises N. Overall, the speech comprehensibility is increased for the user, in that in the frequency ranges f1-f4 relevant at a given point in time, the noise suppression is reduced, and at the same time the maximum possible noise suppression takes place, namely in those frequency ranges f1-f4, which presently do not contain speech V.

[0055] Speech V is generally differentiable into the user's own speech, i.e., speech of the user of the hearing aid 2, and external speech, i.e., speech of another person and in particular not of the user. In the present case, only external speech, which does not originate from the user of the hearing aid 2 himself or herself, is recognized as speech V by the speech recognition unit 18. In this way, external speech is deliberately excluded from the suppression by the ANC unit 16 and the user's own speech is still suppressed. This is based on the consideration that especially external speech is important to the user, whereas the user's own speech does not necessarily have to be output with maximum comprehensibility.

[0056] In the exemplary embodiment shown, the speech recognition unit 18 has a Wiener filter 20 for each of the frequency ranges f1-f4, for recognizing speech V. Depending on how many frequency ranges f1-f6 are analyzed by the speech recognition unit 18, correspondingly many Wiener filters 20 are present, in FIG. 2 therefore four Wiener filters 20. A Wiener filter 20 has a reaction time which is, for example, a few milliseconds or less than 1 ms, so that a nearly instantaneous reaction to the presence of speech V is possible and the ANC strength A is deliberately reduced in a respective frequency range f1-f4 at those times at which speech V is present in the respective frequency range f1-f4. The Wiener filter 20 is used in this context as a stationarity detector, which indicates how quickly a signal changes. In a more general embodiment (not explicitly shown), another stationarity detector is used instead of the Wiener filter 20.

[0057] The hearing aid 2 shown additionally has a filter bank 22 having multiple channels 24, each of which is in each case associated with one of the frequency ranges f1-f6. The filter bank 22 is an array of bandpass filters, which each only let pass a certain frequency component, namely one of the frequency ranges f1-f6, of an incoming signal, the input signal E in this case, and output it as the outgoing signal. The sum of the outgoing signals of the channels 24 still corresponds to the input signal E, however. In the present case, the input signal E, which is generated by the microphone 8, is supplied to the filter bank 22, so that the input signal E is divided onto the diverse channels and then each frequency range f1-f6 is processable individually. The filter bank 22 accordingly generates a divided input signal E from the input signal E, which divided input signal is then supplied to the ANC unit 16 and also the speech recognition unit 18 in this case, to be utilized, i.e., processed by each of these two units in a frequency-selective manner. In principle, it is possible to supply the entire divided input signal E and then only to process a part thereof in the ANC unit 16 and the speech recognition unit 18, especially only the frequency ranges f1-f4 in this case. Equivalently thereto, only that part of the input signal E is already supplied which contains the relevant frequency ranges f1-f4 and the remaining frequency ranges f5, f6 are already separated off beforehand. In each case, the input signal E is respectively entirely or partially relayed to the ANC unit 16 and the speech recognition unit 18 from the filter bank 22. The utilization of the individual channels 24 in the ANC unit 16, on one hand, and the speech recognition unit 18, on the other hand, takes place in parallel to one another in this case, i.e., the speech recognition unit 18 and the ANC unit 16 are operated in parallel to one another in the exemplary embodiment shown.

[0058] Each channel 24 has a width which corresponds to the width B of the corresponding frequency range f1-f6, thus 250 Hz by way of example in this case. The filter bank 22 typically has more than 2 channels 24 and regularly a plurality of channels 24, for example, between 10 and 100. In the embodiment shown herein, the filter bank 22 has 40 channels 24.

[0059] As is already clear from the statements above, it is not necessary for the ANC unit 16 and the speech recognition unit 18 to utilize all channels 24 of the filter bank 22, rather a subset is already sufficient, the frequency ranges f1-f4 in this case. In other words: the number of the frequency ranges f1-f4, in which the speech recognition unit 18 recognizes the presence of speech V and for which the ANC strength A is set depending on the presence of speech V, does not necessarily correspond to the number of the channels 24 of the filter bank 22, but rather is sometimes less. The hearing aid 2 accordingly in principle processes a total number of frequency ranges f1-f6, of which not necessarily all are also processed by the ANC unit 16 and the speech recognition unit 18, however. The ANC and the speech recognition for setting the ANC strength A are therefore restricted to a partial range of the overall spectrum G, to a lower part in this case. In the exemplary embodiment shown, the ANC unit 16 is configured to suppress noises V, N only in those frequency ranges f1-f4 which are below a limiting frequency fg, which is illustrated in FIG. 3 by the vertical double dashed line already described. The limiting frequency fg is 1 kHz, for example. In the exemplary filter bank 22 having 40 channels 24 and a respective width B of 250 Hz, only the bottom 4 channels 24 are thus used in the ANC and the associated speech recognition. Both speech V and also interference noises N are regularly present in the range up to 1 kHz.

[0060] In one possible embodiment, the speech recognition unit 18 outputs a discrete measure S, i.e., signal S, for each of the frequency ranges f1-f4 for the presence of speech V, so that the respective ANC strength A is switched between only two values. The discrete measure S is, for example, a value of 0 or 1. As an alternative to the discrete measure S, in another embodiment, the speech recognition unit 18 outputs a continuous measure S, i.e., signal S, for each of the frequency ranges f1-f4 for the presence of speech V, so that the ANC strength A is set continuously. The continuous measure S is, for example, the absolute or relative amplitude of speech V in the respective frequency range f1-f4. A probability is also suitable which indicates how probably speech V is present in the respective frequency range f1-f4.

[0061] In addition, the hearing aid 2 shown herein has a signal processing unit 26 to amplify each of the frequency ranges f1-f6 using a settable amplification, in the present case in parallel to the ANC unit 16 and also in parallel to the speech recognition unit 18. The signal processing unit 26 amplifies the input signal E of the hearing aid 2 and outputs it as the amplified signal. The amplification is either the same for all frequency ranges f1-f6 which are processed by the signal processing unit 18, or frequency-dependent and then different for various frequency ranges f1-f4. The signal processing unit 26 and its settable amplification implement, during the intended use of the hearing aid 2, its actual hearing aid functionality, namely a modification of the input signal E depending on an individual hearing profile of the user, whereby a hearing deficit of the user is compensated for in operation. This actual hearing aid functionality is independent in principle of the control of the ANC unit 16 by using the speech recognition unit 18, however. The amplified signal of the signal processing unit 26 and the feedback signal Sff of the ANC unit 16 are output jointly through the receiver 6 in the present case.

[0062] In the present case, the amplification is also set in a frequency-dependent manner and for this purpose in a respective frequency range f1-f4 upon the presence of speech V. The amplification in this frequency range f1-f4 is set greater than in comparison to cases in which no speech V is present, so that speech V is amplified more than other noises N. In other words: the amplification of the signal processing unit 26 is set inversely to the ANC strength A of the ANC unit 16, so that speech V in particular is amplified using the signal processing unit 26. If speech V is present, the amplification is increased and the ANC strength A is reduced in the respective frequency range f1-f4, and vice versa if no speech V is present. The control of the signal processing unit 26 and the setting of its amplification take place, for example, analogously to the control of the ANC unit 16 and the setting of the ANC strength, for example, by using the signal S. However, this is not explicitly shown in FIG. 2.

[0063] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: [0064] 2 hearing aid [0065] 4 earpiece [0066] 6 receiver [0067] 8 microphone [0068] 10 housing [0069] 12 control unit [0070] 14 auditory canal [0071] 16 ANC unit [0072] 18 speech recognition unit [0073] 20 Wiener filter [0074] 22 filter bank [0075] 24 channel [0076] 26 signal processing unit [0077] A ANC strength [0078] B width [0079] E input signal [0080] f frequency [0081] f1, f2, f3, f4, f5, f6 frequency range [0082] fg limiting frequency [0083] G overall spectrum [0084] N other noise, interference noise (noise in general) [0085] P1 path [0086] P2 path [0087] S signal, measure (of the speech recognition unit) [0088] Sff feedforward signal [0089] V speech (noise in general)