Method for operating a hearing aid system, and hearing aid system

Abstract

A method operates a hearing aid system in which a dynamic range scheme for an automatic gain control is modified depending on the situation. A gain factor is set by the automatic gain control which has a dynamic range processor operated with a dynamic range scheme defining the gain factor in dependence on a level of an input signal. A corresponding hearing aid system carries out this method.

Claims

1. A method for operating a hearing aid system in a current acoustic environment, the hearing aid system having a signal processor, which comprises the steps of: generating, via the signal processor, an output signal from an input signal by amplifying the input signal by a gain factor; outputting the output signal via a receiver of the hearing aid system; setting the gain factor by an automatic gain control, which has a dynamic range processor operated with a dynamic range scheme defining the gain factor in dependence on a level of the input signal; operating the hearing aid system in a program to which the dynamic range scheme is assigned, with which the dynamic range processor is operated during operation in the program; determining at least one situation parameter characterizing the current acoustic environment, the at least one situation parameter indicates whether speech is present in the current acoustic environment or not; and during operation in the program, modifying an assigned dynamic range scheme depending on the at least one situation parameter, so that the dynamic range processor is operated with a modified dynamic range scheme, the dynamic range scheme is modified in favor of speech intelligibility if the speech is present, and otherwise in favor of sound quality.

2. The method according to claim 1, wherein the dynamic range processor is a compressor, so that the dynamic range scheme is a compression scheme.

3. The method according to claim 1, wherein the dynamic range processor is an expander, so that the dynamic range scheme is an expansion scheme.

4. The method according to claim 1, wherein: the dynamic range scheme is modified by changing at least one parameter of the dynamic range scheme; and the at least one parameter is selected from the group of parameters consisting of: a switch-on time, a switch-off time, a knee point, a compression ratio, and an expansion ratio.

5. The method according to claim 1, wherein the at least one situation parameter is a signal-to-noise ratio of the current acoustic environment, so that the dynamic range scheme is modified depending on the signal-to-noise ratio of the current acoustic environment.

6. The method according to claim 5, wherein: the signal-to-noise ratio is a ratio of a signal which originates from a speaker and a noise which originates from at least one sound source; the dynamic range scheme has two time constants, namely a switch-on time and a switch-off time; and in a case of a negative signal-to-noise ratio at least one of the time constants is reduced and conversely, in a case of a positive signal-to-noise ratio at least one of the time constants is increased.

7. The method according to claim 1, wherein: the at least one situation parameter is an environment class, so that the dynamic range scheme is modified depending on the environment class; and the environment class is selected from the group of classes consisting of: speech, music, and noise.

8. The method according to claim 1, wherein: the at least one situation parameter is a motion pattern, so that the dynamic range scheme is modified depending on a motion of the hearing aid system; and the motion pattern is selected from the group of motion patterns consisting of: a resting position, a walking motion, a running motion, and driving.

9. The method according to claim 1, wherein the at least one situation parameter is a stationarity of the current acoustic environment and of the input signal, so that the dynamic range scheme is modified depending on the stationarity of the current acoustic environment.

10. The method according to claim 1, wherein the at least one situation parameter is a diffuseness of the current acoustic environment, so that the dynamic range scheme is modified depending on the diffuseness of the current acoustic environment.

11. The method according to claim 1, wherein the at least one situation parameter is a distance from the hearing aid system to a sound source, in the current acoustic environment, so that the dynamic range scheme is modified depending on the distance.

12. The method according to claim 1, wherein: the at least one situation parameter is a reverberation time of the current acoustic environment, so that the dynamic range scheme is modified depending on the reverberation time; the dynamic range scheme has two time constants, namely a switch-on time and a switch-off time; and the reverberation time is determined on a recurring basis, and in an event of an increase in the reverberation time, at least one of the time constants is increased and conversely reduced in an event of a decrease in the reverberation time.

13. The method according to claim 1, wherein the one program is a universal program.

14. The method according to claim 1, wherein the dynamic range scheme is modified as a function of frequency.

15. The method according to claim 14, wherein the dynamic range scheme is modified by changing a switch-on time of the dynamic range scheme or a switch-off time of the dynamic range system, or both, as a function of frequency.

16. A method for operating a hearing aid system in a current acoustic environment, the hearing aid system having a signal processor, which comprises the steps of: generating, via the signal processor, an output signal from an input signal by amplifying the input signal by a gain factor; outputting the output signal via a receiver of the hearing aid system; setting the gain factor by an automatic gain control, which has a dynamic range processor operated with a dynamic range scheme defining the gain factor in dependence on a level of the input signal; operating the hearing aid system in a program to which the dynamic range scheme is assigned, with which the dynamic range processor is operated during operation in the program; determining at least one situation parameter characterizing the current acoustic environment; making a distinction between speech frequency bands and speech-free frequency bands; changing a parameter of the dynamic range scheme as a function of frequency by setting the parameter over a particular frequency band according to whether the particular frequency band is the speech frequency band or the speech-free frequency band; and during operation in the program, modifying an assigned dynamic range scheme depending on the at least one situation parameter and frequency, so that the dynamic range processor is operated with a modified dynamic range scheme.

17. The method according to claim 16, wherein: the at least one situation parameter is a signal-to-noise ratio of the current acoustic environment; in a case of a negative signal-to-noise ratio over the speech frequency band, at least one time constant is reduced and in a case of a positive signal-to-noise ratio the at least one time constant is increased; and over the speech-free frequency band, in a case of a negative signal-to-noise ratio the at least one time constant is increased and in the case of a positive signal-to-noise ratio the at least one time constant is reduced.

18. A hearing aid system, comprising: a signal processor configured to carry out a method according to claim 1; and a receiver for outputting the output signal.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is an illustration showing a hearing aid system;

(2) FIG. 2 is a block circuit diagram of the hearing aid system; and

(3) FIG. 3 is a graph showing a frequency-dependent modification of a parameter of a dynamic range scheme.

DETAILED DESCRIPTION OF THE INVENTION

(4) Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a hearing aid system 2, which here is configured as a hearing aid, more precisely as an RIC device, which is worn behind the ear by a user, in particular one with a hearing impairment. As a hearing aid, the hearing aid system 2 in the exemplary embodiment has one or more microphones and here two micro-phones 4, for generating an input signal E from sound signals from the environment. The presence of a microphone 4 in the hearing aid system is not mandatory, however, so that a variant of the hearing aid system 2 does not have a microphone and is a set of headphones, for example. Furthermore, the hearing aid system 2 has a signal processor 6 and a receiver 8, in addition to a power supply and a battery 10. The hearing aid system 2 here also has a housing 12, in which the microphones 4, the signal processor 6 and the battery 10 are arranged. The receiver 8 is connected to the housing via a supply line 14 and in FIG. 1 is integrated into an ear-piece, which is inserted into the user's ear.

(5) In operation, the microphones 4 convert the sound signals in the environment into an input signal E, which is fed to the signal processor 6 and modified by it. In this way, the signal processor 6 generates an output signal A, which is thus a modified input signal E. In this case, the input signal E is amplified with a certain gain factor V. The output signal A, i.e. the amplified input signal E, is finally output to the user by means of the receiver 8. The input signal E and the output signal A are electrical signals. The receiver 8 then converts the output signal A into a sound signal.

(6) The hearing aid system 2 is either monaural or binaural. For example, a binaural hearing aid system 2 then has two housings 12 with the associated components as shown in FIG. 1, wherein the signal processor 6 does not need to be identical in both cases.

(7) In FIG. 2, the hearing aid system 2 is shown as a block circuit diagram. The signal processor 6 has an amplifier 16, to which the input signal E is fed and which then amplifies this signal and forwards it to the receiver 8 as the output signal A. The amplification in the amplifier 16 is carried out with a gain factor V, which is adjusted by an automatic gain control. The latter has a dynamic range processor 18 for this purpose. The hearing aid system 2 is operated in a program to which a specific dynamic range scheme is assigned, with which the dynamic range processor 18 is operated during operation in the one program. The respective dynamic range scheme defines the gain factor V as a function of a level of the input signal E. The function is characterized by various parameters, e.g. in this case by one or more knee points, one or more compression or expansion ratios, a switch-on time (attack), a switch-off time (release) or a combination of these.

(8) The dynamic range processor 18 in this case is either a compressor or an ex-pander or a combination of these. In an exemplary embodiment not shown, there are two dynamic range processors 18, one of which is a compressor and the other an expander, wherein the explanations given for the exemplary embodiment shown then apply analogously.

(9) In addition, a situation parameter S is determined, which characterizes the current acoustic environment and which is then used during operation in the one program to modify the assigned dynamic range scheme. The dynamic range processor 18 is then operated with a modified dynamic range scheme depending on the situation parameter S. To determine the situation parameter S a detector 20 is arranged, which here is part of the hearing aid system 2. The detector 20 is generally connected to the signal unit 6 and specifically to the automatic gain control, in this case to the dynamic range processor 18.

(10) For example, the detector 20 is a speech detector that determines whether speech is present in the environment. Alternatively, the detector 20 determines a signal-to-noise ratio in the environment as the situation parameter S. For this purpose, in a suitable design the input signal E is fed to the detector 20, so that the latter determines the signal-to-noise ratio of the input signal E as the situation parameter S. Alternatively, the detector 20 is a classifier, which uses the input signal E, for example, to assign the environment to a specific environment class. Alternatively, the detector 20 is a motion detector, for example an acceleration sensor, which determines a movement pattern as the situation parameter S. The motion detector determines, for example, whether the user is moving or not, how fast the user is moving, or in which direction or a combination of these. Alternatively, the detector 20 is a stationarity detector, which determines the stationarity of the environment, i.e., the temporal dynamic range of the sound signals from the environment. For this purpose, for example, the detector 20 is supplied with the input signal E, the stationarity of which, i.e. its temporal variation, is then determined by the detector 20 and output as the situation parameter S. Alternatively, the detector 20 is a diffuseness detector, which determines the diffuseness of the environment, i.e., the spatial distribution of the sound signals in the environment. For this purpose, for example, the input signal E is fed to the detector 20, the directedness of which, i.e. its spatial level distribution, is then determined by the detector 20 and output as the situation parameter S. Alternatively, the detector 20 is a distance measuring device which determines the distance of the hearing aid system 2 from a sound source in the environment and then outputs this distance as the situation parameter S. Alternatively, the detector 20 determines the reverberation time in the environment, e.g. by analyzing the input signal E. In a variant not shown, a plurality of identical or different detectors 20 mentioned above are combined.

(11) FIG. 3 shows an exemplary embodiment of a frequency-dependent modification of the dynamic range scheme. In this case, a parameter of the dynamic range scheme is varied differently for different frequencies f depending on the situation. The input signal E has a frequency spectrum, which here is divided into three frequency bands B1-B3. Depending on the situation parameter S, the dynamic range scheme is now not merely modified in the same way for the entire frequency spectrum, but specifically for the individual frequency bands B1-B3. The previously described method, in which the dynamic range scheme is modified, is thus carried out in parallel, so to speak, in the frequency bands B1-B3. In the exemplary embodiment shown, the switch-off time t_r of the dynamic range scheme is changed as a function of frequency. In addition, a distinction is made between speech frequency bands B2, in this case from 800 Hz to 4 kHz, and speech-free frequency bands B1, B3, in this case below 800 Hz and above 4 kHz. In a variant not shown here, a more detailed division of the frequency spectrum is carried out, in which the speech frequency bands correspond to individual sounds or formants, and all other frequencies then form speech-free frequency bands.

(12) The switch-off time t_r and in general a parameter of the dynamic range scheme is in this case varied as a function of frequency by setting it on a particular frequency band B1-B3 according to whether this frequency band B1-B3 is a speech frequency band B2 or a speech-free frequency band B1, B3. The frequency-dependent modification therefore corresponds to a speech-dependent modification. In FIG. 3, this is combined with a design in which the situation parameter S is a signal-to-noise ratio of the current acoustic environment. The frequency-dependent switch-off time t_r in the case of a positive signal-to-noise ratio is shown in FIG. 3 by solid lines and in the case of a negative signal-to-noise ratio by dashed lines. In the case of a negative signal-to-noise ratio, over the speech frequency band B2 the switch-off time t_r is reduced and conversely, in the case of a positive signal-to-noise ratio the switch-off time t_r is increased. On the other hand, conversely over the speech-free frequency bands B1, B3 in the case of a negative signal-to-noise ratio the switch-off time t_r is increased and in the case of a positive signal-to-noise ratio the switch-off time t_r is reduced. “Reduced” here means that a fast switch-off time t_r is set, and “increased” means that a slow switch-off time t_r is set. However, the same procedure is in principle also suitable for the switch-on time.

(13) As an alternative or in addition to the frequency-dependent modification of the time constants, in another suitable design a different parameter of the dynamic range scheme is modified as a function of the frequency, e.g. a compression or expansion ratio or a respective knee point are changed independently of each other, and thus possibly differently, in different frequency bands.

LIST OF REFERENCE SIGNS

(14) 2 hearing aid system 4 microphone 6 signal processor 8 receiver 10 battery 12 housing 14 supply line 16 amplifier 18 dynamic range processor 20 detector A output signal B1, B3 speech-free frequency band B2 speech frequency band E input signal S situation parameter t_r switch-off time V gain factor