Method for operating a hearing device, and hearing device

Abstract

A method for operating a hearing device is specified. The hearing device has at least one microphone that picks up an input sound signal and converts it into an electrical input signal. The hearing device has a signal processing section that modifies the electrical input signal on the basis of an audiogram of a user and thereby generates a first electrical output signal. The hearing device has an active noise reduction system that generates a second electrical output signal in order to reject a noise component. The hearing device has a receiver that converts the first electrical output signal and the second electrical output signal into an output sound signal, for output to the user. The active noise reduction system is operated in parallel with the signal processing section. A corresponding hearing device is programmed to perform the method.

Claims

1. A method for operating a hearing device having at least one microphone, a signal processing section, an active noise reduction system, a delay unit, and a receiver, which comprises the steps of: picking up an input sound signal, via the at least one microphone, and converting the input sound signal into an electrical input signal; modifying, via the signal processing section, the electrical input signal on a basis of an audiogram of a user and thereby generating a first electrical output signal; generating, via the active noise reduction system, a second electrical output signal in order to reject a noise component, wherein the active noise reduction system is operated in parallel with the signal processing section; setting a time difference between the first electrical output signal and the second electrical output signal via the delay unit; and converting, via the receiver, the first electrical output signal and the second electrical output signal into an output sound signal, for output to the user.

2. The method according to claim 1, wherein the active noise reduction system is an active noise cancellation system, an active occlusion reduction system or an ANC and AOR system.

3. The method according to claim 1, wherein the time difference is set in a range from 2 ms to 5 ms.

4. The method according to claim 1, wherein: the hearing device has two modes of operation, namely a rejection mode, in which the active noise reduction system is activated, and a normal mode, in which the active noise reduction system is deactivated; and the time difference of the delay unit is set such that a delay between the electrical input signal of the signal processing section and the first electrical output signal thereof is greater in the rejection mode than in the normal mode.

5. The method according to claim 1, wherein: the hearing device has multiple modes of operation in which the signal processing section has a different processing time in each case; and the time difference added by the delay unit is set on a basis of a mode of operation and hence on a basis of a respective processing time.

6. The method according to claim 1, wherein: the at least one microphone generates the electrical input signal that is forwarded both to the signal processing section and to the noise reduction system; and the signal processing section generates the first electrical output signal and the noise reduction system generates the second electrical output signal on a basis of the electrical input signal.

7. The method according to claim 1, wherein: the at least one microphone is one of at least two external microphones including a first external microphone and a second external microphone; and the external microphones generate electrical input signals including a first input signal and a second input signal, one of the first and second electrical input signals is forwarded to the signal processing section, while the other is forwarded to the noise reduction system.

8. The method according to claim 1, wherein the hearing device has a further internal microphone that generates a further input signal that is supplied to the noise reduction system, which then generates the second electrical output signal on a basis of the further input signal from the further internal microphone.

9. The method according to claim 1, wherein the first electrical output signal and the second electrical output signal are combined with one another outside the signal processing section and the noise reduction system and are forwarded to the receiver, which finally generates and outputs the output sound signal.

10. The method according to claim 1, wherein: the noise reduction system has an audio input by way of which the first electrical output signal of the signal processing section is routed to the noise reduction system; the second electrical output signal is generated in the noise reduction system and combined with the first electrical output signal, so that the noise reduction system outputs a joint output signal for the signal processing section and the noise reduction system; and the joint output signal is forwarded to the receiver, which finally generates and outputs the output sound signal.

11. The method according to claim 1, wherein the signal processing section of the hearing device has a processing time of no more than 1 ms.

12. A method for operating a hearing device having at least one microphone, a signal processing section, an active noise reduction system and a receiver, which comprises the steps of: picking up an input sound signal, via the at least one microphone, and converting the input sound signal into an electrical input signal; modifying, via the signal processing section, the electrical input signal on a basis of an audiogram of a user and thereby generating a first electrical output signal, wherein the signal processing section of the hearing device has a processing time of no more than 2 ms; generating, via the active noise reduction system, a second electrical output signal in order to reject a noise component, wherein the active noise reduction system is operated in parallel with the signal processing section; and converting, via the receiver, the first electrical output signal and the second electrical output signal into an output sound signal, for output to the user.

13. A method for operating a hearing device having at least one microphone, a signal processing section, an active noise reduction system and a receiver, which comprises the steps of: picking up an input sound signal, via the at least one microphone, and converting the input sound signal into an electrical input signal; modifying, via the signal processing section, the electrical input signal on a basis of an audiogram of a user and thereby generating a first electrical output signal; fully integrating a delay unit in the signal processing section, so that the electrical input signal is first modified and only then passes through the delay unit and is delayed, and is finally output as the first electrical output signal being a delayed output signal; generating, via the active noise reduction system, a second electrical output signal in order to reject a noise component, wherein the active noise reduction system is operated in parallel with the signal processing section; and converting, via the receiver, the first electrical output signal and the second electrical output signal into an output sound signal, for output to the user.

14. The method according to claim 13, wherein: the delay unit is split into a plurality of subunits, among which a first subunit is integrated in the signal processing section and another, second subunit is integrated in the noise reduction system; and one of the subunits produces a firmly predefined time difference and the other subunit produces a time difference that is adjustable in a predefined range.

15. A hearing device, comprising: at least one microphone; a signal processing section; an active noise reduction system; and a receiver; the hearing device configured to perform a method according to claim 1.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a flow chart showing a method for operating a hearing device according to the invention;

(2) FIG. 2 is a block diagram showing a hearing device;

(3) FIG. 3 is a block diagram showing a variant of the hearing device from FIG. 2;

(4) FIG. 4 is a block diagram showing a further variant of the hearing device from FIG. 2;

(5) FIG. 5 is a block diagram showing a further variant of the hearing device from FIG. 2; and

(6) FIG. 6 is a block diagram showing a further variant of the hearing device from FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

(7) Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a method for operating a hearing device 2 in the form of a flowchart. Different variants of hearing devices 2 suitable therefor are shown in each of FIGS. 2 to 6. However, the invention is not restricted to the variants specifically shown, but these are preferred embodiments.

(8) In general, the hearing device 2 has at least one microphone 4, 6 that picks up an input sound signal ES and converts it into an electrical input signal E1 in a method step V1. The hearing device 2 further has a signal processing section 8 that modifies the electrical input signal E1 on the basis of an audiogram of a user and thereby generates a first electrical output signal A1 in a method step V2. The input signal E1 here is modified in a modification unit 10, which is a part of the signal processing section 8. The hearing device 2 furthermore has an active noise reduction system 12 that generates a second electrical output signal A2, to reject a noise component, in a method step V3. The active noise reduction system 12 is also referred to as noise reduction system 12 in the present case for short. The noise reduction system 12 is operated in parallel with the signal processing section 8, as discernible from FIG. 1 in particular. The first and second electrical output signals A1, A2 are each also referred to as output signal A1, A2 for short. The two output signals A1, A2 are combined in a method step V4. The hearing device 2 moreover has a receiver 14 that converts the first electrical output signal A1 and the second electrical output signal A2 into a joint output sound signal AS, for output to the user, in a method step V5. The output sound signal AS is an acoustic output signal. The second electrical output signal A2 is in a form such that a noise component in the output sound signal AS is rejected. The noise component is for example an ambient sound and generally not a wanted signal. The noise component is a part either of the aforementioned input sound signal ES or of another input sound signal picked up by means of an additional microphone 16, 18.

(9) In the case of the hearing devices 2 shown, the method for operating same involves an output sound signal AS being generated for the user of the hearing device 2 by virtue of an input sound signal ES first being picked up from the surroundings by means of multiple external microphones 4, 6. The respective microphone 4, 6 generates an electrical input signal E1 from the input sound signal ES. In FIG. 1, the two microphones 4, 6 thus generate two input signals E1, which are forwarded to the signal processing section 8. The signal processing section 8 modifies the input signals E1 and generates the first electrical output signal A1 therefrom. The modification is dependent on the individual hearing loss of the user and is affected on the basis of an individual audiogram stored for example in a memory of the hearing device 2, which is not shown in more detail. The output signal A1 is finally forwarded to the receiver 14, which is driven by the output signal A1 and outputs a corresponding acoustic output sound signal AS. In general, the procedure containing pickup of the input sound signal ES, generation of at least one input signal E1 therefrom, modification of the input signal, resultant generation of an output signal A1 and subsequent generation of the output sound signal AS is all in all a hearing device function that is a core functionality of the hearing device 2.

(10) The active noise reduction system 12 behaves toward the signal path in a fundamentally similar manner to the signal processing section 8 for the hearing device function. The noise reduction system 12 likewise initially involves one or more input sound signals ES being picked up from the surroundings by means of one or more microphones 4, 6, 16, 18 in method step V1, these microphones 4, 6, 16, 18 not necessarily being the same as for the hearing device function. In this case too, the input sound signal ES typically has a noise component. The respective microphone 4, 6, 16, 18 generates from the input sound signal ES an electrical input signal E2 that accordingly also contains the noise component and that is forwarded to the noise reduction system 12. The latter analyses the input signal E2 in method step V3 and generates therefrom an electrical output signal, in particular the aforementioned second electrical output signal A2, which is then the opposite of the input signal E2 or at least portions thereof, specifically the noise component. The output signal A2 from the noise reduction system 12 is accordingly basically an inverted input signal E2. The output signal A2 is finally forwarded to the receiver 14 of the hearing device 2, which receiver is driven by the output signal A2 in method step V5 and outputs a corresponding output sound signal AS that is accordingly inverted with respect to the input sound signal ES and thereby cancels out, i.e. ultimately rejects, the noise component. The procedure containing pickup of the input sound signal ES, generation of the input signal E2 therefrom, analysis of the input signal, resultant generation of the output signal A2 to reject a noise component and subsequent generation of the output sound signal AS is all in all a noise reduction function.

(11) The active noise reduction system 12 differs from the signal processing section 8 in the present case in that the noise reduction system aims to modify a sound signal and, to this end, actuates the receiver 14 accordingly, whereas the signal processing section aims to modify an electrical signal so that a specific sound signal is output. The noise component rejected by the noise reduction system 12 is outside the hearing device 2. The output sound signal AS from the noise reduction system 12 is output via the same receiver 14 as the output sound signal AS from the signal processing section 8. The receiver 14 is actuated both with the first and with the second output signal A1, A2, i.e. the output signals are overlaid and collectively supplied to the receiver 14, which then outputs them as output sound signal AS. Effectively, the receiver 14 is accordingly all in all actuated by means of a joint output signal A1+A2 and outputs a joint output sound signal AS. This output sound signal AS contains firstly a user component, which is generated for the user individually by the signal processing section 8 on the basis of the audiogram, and secondly a rejection component, which rejects noise components, i.e. perturbing sound signals e.g. from the surroundings or from the user, in the auditory canal. The cancellation of a noise component by the noise reduction system 12 accordingly takes place in the acoustic domain.

(12) Two variants of the active noise reduction system 12 are combined with one another in the exemplary embodiments shown, but are also used independently of one another and individually in other variants, which are not shown. The first variant is an ANC (active noise cancelling), i.e. an active noise reduction system, which involves rejecting ambient sounds that enter the auditory canal from the outside and past an earmold that may be present for the hearing device 2 and represent a noise component. The input signal E2 is generated either using the same microphone 4, 6 as the input signal E1 for the signal processing section 8 or by means of another, additional microphone 16, 18. The second variant is an AOR (active occlusion reduction), which involves rejecting sounds in the auditory canal, above all inherent sounds, i.e. sound signals that are produced by the user himself, or standing waves inside a predominately sealed auditory canal. In this instance, the input signal E2 for the noise reduction system 12 is generated by means of an internal microphone 18 and not using the microphones 4, 6 that generate the input signal E1 for the signal processing section 8 and also not using the external microphone 16. In the case of the ANC the microphone 4, 6, 16 is accordingly directed outward, whereas in the case of the AOR the microphone 18 is directed inward.

(13) In order to provide both a hearing device function and a noise reduction function in the hearing device 2, the signal processing section 8 and the active noise reduction system 12 are operated in parallel in the present case. This is understood to mean that the signal processing section 8 and the active noise reduction system 12 are operated independently of one another, i.e. they form two mutually separate processing blocks inside the hearing device 2, as is also evident from FIGS. 2 to 6. The signal processing section 8 and the active noise reduction system 12 are each in the form of an electronic circuit and the two circuits are arranged for example at different points on a microchip or on different microchips. The active noise reduction system 12 is not part and not a subfunction of the signal processing section 9 and operates independently thereof in principle. The parallel operation means that the active noise reduction system 12 thus does not intervene in the modification of the input signal E1 by the signal processing section 8, and conversely the signal processing section 8 also does not intervene in the generation of the output signal A2 from the noise reduction system 8. The hearing device function and the noise reduction function are therefore implemented as parallel processes in the hearing device 2.

(14) The signal processing section 8 requires a certain processing time in order to modify the input signal E1 and for method step V2 in general. The noise reduction system 12 similarly requires a certain processing time in order to analyse the input signal E2 and in order to output the output signal A2 and for method step V3 in general. This respective processing time is ideally as short as possible, in order to avoid a delayed output as far as possible. In connection with the signal processing section 8, at least a portion of the input sound signal ES normally enters the auditory canal of the user and is overlaid with the output sound signal AS. Due to the delay time of the signal processing section 8, the input sound signal ES and the output sound signal AS are offset in time by a time lag. If the processing time is too long, then the time lag is perceptible to the user and is typically sensed as a nuisance. In the noise reduction system 12, the output sound signal AS inherently needs to be overlaid with the input sound signal ES in a specific manner in order to obtain a maximum effect, that is to say maximum cancellation. Any delay before the output sound signal AS is output leads to an additional phase shift between said output sound signal and the input sound signal ES, with the result that the overlay is not optimum and the cancellation is accordingly incomplete. The processing time of the signal processing section 8 is no more than 2 ms, for example. The processing time of the noise reduction system 12, whether ANC or AOR or both, is 100 μs is to 150 μs, for example.

(15) In each of the exemplary embodiments shown, the hearing device 2 has a delay unit 20, in order to set a time difference between the first output signal A1 and the second output signal A2. The hearing device 2 therefore has an adjustable time difference, for which either a firm value is predefined and the delay unit 20 is then either activated or deactivated or which is adjustable within a predefined range. For this purpose, the delay unit 20 has a ring buffer or is in the form of a ring buffer, for example. The delay unit 20 is used by and large to reduce a correlation between the output signals A1, A2. For the purpose of controlling the delay unit 20 and for the purpose of setting the time difference, the hearing device 2 has a correlation measurement unit, for example, not shown in more detail, which determines a correlation between the first and second output signals A1, A2 and actuates the delay unit 20 so that a time difference that minimizes the correlation is set. In the present case, the time difference is set in a range from 2 ms to 5 ms.

(16) In a variant, the time difference is activated only in a rejection mode of the hearing device 2 and is otherwise, e.g. in a normal mode, deactivated. In the rejection mode, the active noise reduction system 12 is activated, otherwise, and specifically in the normal mode, it is deactivated, however. In the normal mode, the time difference is then chosen to be as small as possible, so that only the delay time remains for the signal processing section, i.e. a delay between the input signal E1 and the output signal A2 is as short as possible, and hence the best possible hearing experience is ensured. In the rejection mode, on the other hand, the additional time difference is consciously added to the processing time of the signal processing section 8, so that the interference and correlation effects that potentially occur are reduced.

(17) An alternative or additional possibility is also a variant in which the hearing device 2 has multiple modes of operation in which the signal processing section 8 has a different processing time in each case, and wherein the time difference added by the delay unit 20 is then set on the basis of the mode of operation and hence on the basis of the respective processing time of the signal processing section 8. In a variant, the time difference is then set in the respective mode of operation to be greater the shorter the respective processing time.

(18) As becomes clear from FIGS. 2 to 6, parallel operation of the signal processing section 8 and the active noise reduction system 12 can be implemented in different ways. Different suitable configurations are obtained in particular in respect of the following three aspects: first, by the selection of microphones 4, 6, 16, 18 and the respective connection thereof to the signal processing section 8 and the noise reduction system 12. Second, by the type of combination of the two output signals A1, A2. Third, by the specific configuration, arrangement and control of the delay unit 20. In addition to the variants shown, other variants, which are not shown, exist that are obtained through different combination of the various configurations in respect of the three cited aspects.

(19) In FIG. 2 the hearing device 2 has two external microphones 4, 6, which each generate an input signal E1, E2 that is forwarded as input signal E1 to the signal processing section 8 and as input signal E2 also to the noise reduction system 12. The signal processing section 8 generates the first output signal A1 on the basis of the two input signals E1 from the external microphones 4, 6 and the noise reduction system 12 generates the second output signal A2 on the basis of the same two input signals E2 from the external microphones 4, 6.

(20) By contrast, the hearing device 2 in FIGS. 3 to 6 has two external microphones 4, 6, which each generate an input signal E1, and a further external microphone 16, which generates an input signal E2. The input signals E1 are forwarded exclusively to the signal processing section 8, while the other input signal E2 is forwarded exclusively to the noise reduction system 12. The signal processing section 8 generates the first output signal A1 on the basis of the input signals E1 and the noise reduction system 12 generates the second output signal A2 on the basis of the other input signal E2.

(21) In comparison with the configuration in FIG. 2, in which the same input signal E1, E2 is forwarded both to the signal processing section 8 and to the noise reduction system 12, the signal processing section 8 and the noise reduction system 12 in FIGS. 3 to 6 use the input signals E1, E2 from different external microphones 4, 6, 16, so that there is already a reduced correlation at the input.

(22) Given the aforementioned use of an input signal E2 from one or more external microphones 4, 6, 16, it has been assumed that the noise reduction system 12 is an ANC. In the present case, the noise reduction system 12 is additionally also an AOR and uses a further input signal E2 from an internal microphone 18 of the hearing device 2. The noise reduction system 12 in the present case thus generates the output signal A2 on the basis of one or more input signals E2 from external microphones 4, 6, 16 and additionally also on the basis of an input signal E2 from an internal microphone 18. The configurations having external microphones 4, 6, 16 are arbitrarily combinable with the configuration having an internal microphone 18. In principle, a single external microphone 4, 6, 16 is also already sufficient, at least for a hearing device having ANC. For a hearing device having AOR, at least one internal microphone 18 is additionally required.

(23) In the exemplary embodiments of FIGS. 2 and 3 the first output signal A1 and the second output signal A2 are combined with one another, in this case added, outside the signal processing section 8 and the noise reduction system 12 and are forwarded to the receiver 14, which finally generates and outputs a corresponding output sound signal AS. The combination is effected by means of an adder, for example, which is not shown in more detail. By contrast, the noise reduction system 12 in FIGS. 4 to 6 has an audio input 24 by way of which the first output signal A1 from the signal processing section 8 is routed to the noise reduction system 12, so that the first output signal A1 is a further input signal, as it were, for said noise reduction system. The second output signal A2 is then generated in the noise reduction system 12 on the basis of the input signals E2 from the microphones 4, 6, 16, 18 and combined with the first output signal A1, so that the noise reduction system 12 then outputs a joint output signal A1+A2 for the signal processing section 8 and the noise reduction system 12. This joint output signal A1+A2 is forwarded to the receiver 14, which finally generates and outputs a corresponding output sound signal AS. Whereas in the configuration of FIGS. 2 and 3 with downstream combination the two output signals A1, A2 are simply combined to form a joint output signal A1+A2, in the configuration of FIGS. 4 to 6 with the audio input 24 the first output signal A1 is additionally looped through the noise reduction system 12 and combined therein with the second output signal A2, in order to accordingly generate a joint output signal A1+A2. The combination of the first and second output signals A1+A2 is thus provided once outside the noise reduction system and once inside it.

(24) The delay unit 20 in the exemplary embodiments of FIGS. 2 to 4 and 6 is fully integrated in the signal processing section 8 and, in the present case, even arranged at the output thereof, so that the input signal E1 is thus first modified by means of the modification unit 10 and only then passes through the delay unit 20 and is delayed, and is finally output as a delayed output signal A1.

(25) As an alternative to full integration in the signal processing section 8, the delay unit 20 in the exemplary embodiment of FIG. 5 is split into multiple subunits 22, among which one is integrated in the signal processing section 8 and another is integrated in the noise reduction system 12. In this case, the subunit 22 in the signal processing section 8 is arranged at the output thereof and the subunit 22 in the noise reduction system 12 is arranged at the audio input 24 thereof, so that the delayed output signal A1 from the signal processing section 8 is delayed further on entering the noise reduction system 12. In the present case the subunit 22 in the signal processing section 8 produces a firmly predefined time difference and the other subunit 22 in the noise reduction system 12 produces a time difference that is adjustable in a predefined range. The arrangement may alternatively be the other way round. All in all, the time difference of the delay unit 20 is therefore made up of a static component, namely the predefined time difference, and a flexible component, namely the adjustable time difference.

(26) In the exemplary embodiment of FIG. 6 the delay unit 20 is fully integrated in the signal processing section 8 and produces a time difference that is adjustable in a predefined range, so that the time difference of the delay unit 20 is accordingly flexible, like the flexible component already described above. However, a flexible component is now produced directly in the signal processing section 8 and an additional static component is in particular not added here. Additionally, the time difference in FIG. 6 is set by virtue of the noise reduction system 12 controlling the delay unit 20 with a control signal S or by virtue of the output signal A1+A2 from the noise reduction system 12 being fed back to the delay unit 20 and therefore being used directly as a control signal therefor. Both variants are shown in FIG. 6, but are also implementable independently of one another.

(27) The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: 2 hearing device 4 microphone 6 microphone 8 signal processing section 10 modification unit 12 noise reduction system 14 receiver 16 microphone 18 microphone 20 delay unit 22 subunit (of the delay unit) 24 audio input A1 first electrical output signal (of the signal processing section) A2 second electrical output signal (of the noise reduction system) A1+A2 joint output signal (sum of A1 and A2) AS output sound signal E1 first electrical input signal (for the signal processing section) E2 second electrical input signal (for the noise reduction system) ES input sound signal S control signal V1 to V5 method step