HEARING DEVICE AND METHOD FOR OPERATING A HEARING DEVICE

Abstract

A hearing device includes at least one microphone configured to capture sound signals within an overall frequency range and to convert them into an input signal. A signal processor is provided for processing the input signal within a lower frequency range that is part of an overall frequency range. A detector is provided for detecting a noise that has frequency components both inside and outside the lower frequency range, namely in an upper frequency range above the lower frequency range. The hearing device is configured in such a way that the detector detects the noise based on its frequency component in the upper frequency range. A method for operating a hearing device is also provided.

Claims

1. A hearing device, comprising: at least one microphone configured to capture sound signals within an overall frequency range and to convert the captured sound signals into an input signal; a signal processor for processing the input signal within a lower frequency range being part of the overall frequency range; a detector for detecting noise having frequency components both within the lower frequency range and outside of the lower frequency range, namely a frequency component in an upper frequency range above the lower frequency range; said detector detecting the noise based on the frequency component of the noise in the upper frequency range.

2. The hearing device according to claim 1, wherein said detector is a pulse detector.

3. The hearing device according to claim 1, wherein said detector is configured as a level detector detecting the noise when an amplitude of the noise in the upper frequency range exceeds a minimum amplitude.

4. The hearing device according to claim 1, wherein said detector is configured as a gradient detector detecting the noise when an amplitude of the noise in the upper frequency range executes a minimum change during a predefined time interval.

5. The hearing device according to claim 1, wherein said detector is configured as a wavelet detector detecting the noise based on a spectral shape of the noise.

6. The hearing device according to claim 1, wherein the noise is at least one of a transient or an impulse noise.

7. The hearing device according to claim 1, wherein the noise is caused by clinking at least one of dishes or cutlery.

8. The hearing device according to claim 1, wherein the lower frequency range is an operating range of said signal processor, and the processing of the input signal by said signal processor is limited to the lower frequency range.

9. The hearing device according to claim 1, wherein a speech frequency range is completely or at least predominantly included within the lower frequency range.

10. The hearing device according to claim 1, wherein the upper frequency range has an upper limit corresponding to at least an upper limit of a speech frequency range.

11. The hearing device according to claim 1, wherein the lower frequency range has an upper limit of 12 kHz.

12. The hearing device according to claim 1, wherein the upper frequency range has a lower limit of 12 kHz.

13. The hearing device according to claim 1, wherein the upper frequency range has an upper limit of 16 kHz.

14. The hearing device according to claim 1, which further comprises: an A/D converter for digitizing the input signal; said A/D converter having a sampling rate; and the upper frequency range has an upper limit corresponding to no more than half of the sampling rate of said A/D converter.

15. A method for operating a hearing device having at least one microphone, a signal processor, and a detector, the method comprising: using the microphone to capture sound signals within an overall frequency range and to convert the captured sound signals into an input signal; using the signal processor to process the input signal within a lower frequency range being part of the overall frequency range; using the detector to detect a noise having frequency components both inside the lower frequency range and outside of the lower frequency range, namely in an upper frequency range above the lower frequency range; and using the detector to detect the noise based on a frequency component of the noise in the upper frequency range.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0043] FIG. 1 is a schematic and block diagram of a hearing device;

[0044] FIG. 2 is a diagram showing a frequency spectrum;

[0045] FIG. 3 shows another frequency spectrum; and

[0046] FIG. 4 shows a portion of the frequency spectrum of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

[0047] Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen an exemplary embodiment of a hearing device 2 according to the invention. The hearing device 2 has at least one microphone 4, which is configured to capture sound signals 6 within an overall frequency range Fg and convert them into an input signal 8. Furthermore, the hearing device 2 has a signal processor 10 for processing the input signal 8 within a lower frequency range Fu which is part of the overall frequency range Fg. Thus, the hearing device 2 has an operating range Fa, which contains at least—and in the exemplary embodiment shown herein, even exclusively—the lower frequency range Fu. The hearing device 2 also has a detector 12 for detecting a noise 14 which has frequency components both inside the lower frequency range Fu as well as outside the same, namely in an upper frequency range Fo above the lower frequency range Fu. This is illustrated in FIG. 2, which shows an example spectrum of the input signal 8, i.e. its amplitude A as a function of the frequency F. For the sake of clarity, the noise 14 and the useful sound 16 are shown separately, although it is clear that they are mixed to form the input signal 8, possibly with additional useful sounds and/or noises, which are not explicitly shown for the sake of clarity. The hearing device 2 is also configured in such a way that the detector 12 detects the noise 14 based on its frequency component in the upper frequency range Fo.

[0048] Preferably, the upper frequency range Fo is directly adjacent to the lower frequency range Fu, but this is not mandatory. In the exemplary embodiment shown, the upper frequency range Fo and the lower frequency range Fo do not overlap. The upper frequency range Fo in this case is also not part of the operating range Fa, but this is not mandatory in itself, so that an embodiment in which the operating range Fa also entirely or partially contains the upper frequency range Fo is also possible and suitable. The upper frequency range Fo is characterized primarily by the fact that fewer useful sounds 16 are present and/or to be expected in this range than in the lower frequency range Fu, as can be seen in the example of FIG. 2. Outside the lower frequency range Fu, the proportion of speech (which is a useful sound 16) is also usually particularly low.

[0049] Sound signals 6 in general and noises 14 in particular are not restricted to the operating range Fa of the hearing device 2, but may also be located outside of it. In particular, transient and/or impulse-like noises 14 are wideband and therefore span a broad frequency range, thus they also have high-frequency components that are typically outside the operating range Fa, as is clear from FIG. 2 for the noise 14 shown there (the terms “component” and “frequency component” are generally considered to be equivalent and are used interchangeably). The detection of such noises 14 is unreliable, in particular if the detection is performed at low frequencies, specifically in the operating range Fa of the hearing device 2, where other stationary and non-stationary noises (not explicitly shown in FIG. 2) are often additionally present that are often louder, i.e. have a higher amplitude A. In addition, non-stationary components of speech can lead to cases of misrecognition, i.e. speech, which is actually a useful sound 16, being incorrectly detected as a noise 14.

[0050] However, it has been observed that the amplitude A of high-frequency noises 14 is often lower than the amplitude A of low-frequency noises 14, which are typically within the operating range Fa. In a restaurant or cafeteria, for example, when cutlery and crockery are struck together they produce a clinking noise 14, which is a quiet, transient and/or impulse-like noise 14 and also has a high-frequency component that is typically outside the operating range Fa, an example of which is shown in FIG. 2. Such noises 14 in particular are then better detected by the hearing device 2, since quiet noises 14 are also detected in the upper frequency range Fo. The risk of mis-detections is reduced, since little or no useful sounds 16 are expected to occur in the upper frequency range Fo, because these are mainly or exclusively located in the lower frequency range Fu, as can also be seen in FIG. 2. Thus, in the present case quiet, transient and/or impulse-like noises 14 are detected, specifically by monitoring the upper frequency range Fo. A transient and/or impulse-like noise 14 is therefore detected based on its frequency component outside the lower frequency range Fu. This exploits the fact that the noise 14 is wideband and has frequency components in both the lower and the upper frequency range Fu, Fo.

[0051] The noise 14 is preferably suppressed by the signal processor 10 and then, if applicable, only within the lower frequency range Fu and not necessarily in the upper frequency range Fo.

[0052] The hearing device 2 shown herein is preferably used to treat a hearing-impaired user, i.e. a user with a hearing deficit. To this end, the hearing device 2 has the microphone 4 mentioned above, which captures sound signals 6 from the surroundings and generates the electrical input signal 8. This electrical input signal 8 is fed for processing (in this case specifically, amplification) to the signal processor 10, also mentioned above, which in this case is also part of a control unit 18 of the hearing device 2. The processing is carried out in particular on the basis of an individual audiogram of the user assigned to the hearing device 2, so that an individual hearing deficit of the user is compensated. As a result the signal processor 10 outputs an electrical output signal 20, which is then output to the user by a receiver 22 of the hearing device 2. In a non-illustrated alternative, the hearing device 2 is simply a headset and then, for example, for the specific suppression of noises 14 it has a noise canceling facility, which benefits accordingly from the detection of noises 14 described herein.

[0053] The exact configuration of the detector 12 is not relevant in this case, more important is the fact that it operates in the upper frequency range Fo and searches for a noise 14 therein. In principle, a conventional detector 12 is suitable, which would otherwise be used on the lower frequency range Fu but now monitors the upper frequency range Fo instead. A limitation of the detector 12 to the upper frequency range Fo results, for example, from the fact that the detector 12 monitors only the upper frequency range Fo or that only the upper frequency range Fo is fed to the detector 12.

[0054] In the embodiment shown herein as an example, the hearing device 2 has a filter bank 24 that divides the input signal into a number of channels, each of which is assigned to a frequency band. The filter bank 24 in this case is configured separately from the signal processor 10, but as an alternative can be integrated into this signal processor 10. The filter bank 24 has a plurality of channels, in particular at least three, but typically a two-digit number. A first subset of the channels then forms the lower frequency range Fu and a second, different subset of the channels analogously forms the upper frequency range Fo, which is then fed to the detector 12. Regardless of this, a filter bank 24 is also advantageous for suppressing the noise 14, because the gain can then be set specifically in each individual channel so that precisely those components that belong to a noise 14 are specifically reduced. An embodiment is also possible in which the filter bank 24 is limited to the lower frequency range Fu and the upper frequency range Fo is routed past the filter bank 24 to the detector 12. This is the case in FIG. 1, according to which the input signal 8 as a whole is fed to the detector 12, which then controls the signal processor 10 to suppress a noise. Alternatively or in addition, the detector 12—as already indicated—controls the filter bank 24 for the suppression. Furthermore, in a non-illustrated variant—as also already indicated—the detector 12 is not supplied with the input signal 8 as a whole, but only the upper frequency range Fo from the filter bank 24.

[0055] In this case the detector 12 is configured as a level detector and thus detects the noise 14 as such if the amplitude A thereof in the upper frequency range Fo exceeds a minimum amplitude M. If the minimum amplitude M in the upper frequency range Fo is exceeded, the detector 12 triggers and thus detects a noise 14. The minimum amplitude M is chosen to be lower (e.g. half the size) than a minimum amplitude M which would be selected for a detector that monitors the lower frequency range Fu. A second detector for the lower frequency range Fu is not used in this case, but in a non-illustrated alternative it is present in addition to the detector 12 described herein for the upper frequency range Fo, e.g. to detect narrow-band noises in the lower frequency range Fu, which is not possible with the detector 12 described herein. Accordingly, the detector for the lower frequency range Fu has a higher minimum amplitude M than the detector 12 for the upper frequency range Fo. In order to detect noises 14 in the lower frequency range Fu, however, a minimum amplitude M is required which is greater than the typical or maximum achievable amplitude A of useful sounds 16 in the lower frequency range Fu, as can be seen from FIG. 2. Since there are either no or only few useful sounds 16 in the upper frequency range Fo, in this case a correspondingly lower minimum amplitude M is possible and quiet noises 14 are also better detected.

[0056] The detector 12 is a gradient-based detector, for example. It is also possible to implement it as a gradient detector or a wavelet detector, as well as a combination of the embodiments mentioned in this case and above.

[0057] As mentioned above, the upper frequency range Fo in the embodiment shown is not part of the operating range Fa of the hearing device 2. To this end, the lower frequency range Fu is an operating range Fa of the signal processor 10, so that the processing of the input signal 8 by the signal processor 10 is limited to the lower frequency range Fu. The signal processor 10 therefore does not process, preferably does not amplify, the upper frequency range Fo, which is only used for the detector 12 and possibly other functions of the hearing device 2 that are of no further relevance in this case. It is irrelevant whether the filter bank 24 only transfers the lower frequency range Fu to the signal processor 10 or whether the signal processor 10 discards the upper frequency range Fu from the signal of the filter bank 24 or simply leaves it unprocessed. An amplification with the aim of compensating for a hearing deficit of the user is not performed in the upper frequency range Fo.

[0058] FIG. 2 also shows a speech frequency range Fs, which in this example completely contains the lower frequency range Fu. In particular, the speech frequency range Fs specifies exactly the frequency range within which speech is located. The speech frequency range F in the present case ranges from 100 Hz to 4 kHz or to 12 kHz if overtones are taken into account. The speech frequency range Fs in the present case is completely included within the operating range. In another possible non-illustrated alternative embodiment, the operating range Fa and the speech frequency range Fs have the same upper limit and/or lower limit. However, embodiments are also possible in which the operating range Fa is larger or smaller than the speech frequency range Fs. Specifically in an embodiment in which the operating range Fa also includes the upper frequency range Fo, the operating range Fa is then larger than the speech frequency range Fs.

[0059] The lower frequency range Fu has an upper limit 26 of 12 kHz, for example. This upper limit 26 in this case is also, but not necessarily, a lower limit 28 of the upper frequency range Fo.

[0060] The upper frequency range Fo has an upper limit 30 which in this case is defined by a technical constraint of the hearing device 2, in particular a limited frequency range of the filter bank 24 and/or a limited sampling rate of an A/D converter 32 (i.e. analog-to-digital converter), which digitizes the input signal 8 from the microphone 4. In the embodiment shown herein, the upper frequency range Fo has a lower limit 28 of 12 kHz and an upper limit 30 of 16 kHz. The lower limit 28 is derived from the same considerations as the upper limit 26 of the lower frequency range Fu. The upper limit 30 of 16 kHz in this case results from the technical constraints of a sampling rate of 32 kHz of the A/D converter 32.

[0061] For further illustration, FIG. 3 shows a frequency spectrum in an exemplary environment, in this case a cafeteria. The frequency F is plotted in the vertical direction and the time T is plotted in the horizontal direction. The amplitude A for a given frequency F at a given time T is represented in grayscale, wherein the brighter/whiter the color, the greater the amplitude A and vice versa, the darker/blacker the color, the lower the amplitude A. In FIG. 3, the upper frequency range Fo is enclosed in a frame for identification, the lower frequency range Fu is directly adjacent to it below the upper frequency range Fo. The frame contains the frequency range from 11 kHz to 16 kHz. In FIG. 4, this frequency range is shown enlarged within the frame of FIG. 3, which makes the structure of the upper frequency range Fo more clearly visible. Numerous bright, vertical stripes are clearly visible, i.e. high amplitudes A for short times T only, which result from impulse-like and/or interfering sounds 14.

[0062] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: [0063] 2 hearing device [0064] 4 microphone [0065] 6 sound signal [0066] 8 input signal [0067] 10 signal processor [0068] 12 detector [0069] 14 interfering sound (noise) [0070] 16 useful sound [0071] 18 control unit [0072] 20 output signal [0073] 22 receiver [0074] 24 filter bank [0075] 26 upper limit (of the lower frequency range) [0076] 28 lower limit (of the upper frequency range) [0077] 30 upper limit (of the upper frequency range) [0078] 32 A/D converter [0079] A amplitude [0080] F frequency [0081] Fa operating range [0082] Fg overall frequency range [0083] Fo upper frequency range [0084] Fs speech frequency range [0085] Fu lower frequency range [0086] M minimum amplitude [0087] T time