Hearing-aid with reduced wind sensitivity and corresponding method

The present invention relates to a hearing aid with multiple microphones, a noise detecting means for detecting a load caused by wind noise, and for outputting a corresponding detection signal, and a signal processing means for driving the plurality of microphones in response to the detection signal. Moreover, the present invention relates to a corresponding method for controlling a plurality of microphones of a hearing aid.

Hearing aids, which also allow directional hearing have, in principle, by the drawn-forward position of the microphones a higher sensitivity to wind. Particularly noticeable this case makes the turbulent flows through the head and the outer ear (pinna) or the edge of the pinna (helix) caused low-frequency pseudo sound. This pseudo noise is audible only in the near field and occurs at the pinna and in the back of the head. Since the microphones functional reasons lie directly adjacent to the pinna, this pseudo sound is picked amplified by the hearing aid, and leads to an unpleasant noise ( "rumble").

So far it has detected wind using two active microphones in a directional hearing aid and the hearing of the directional mode to omnidirectional mode automatically switched. If necessary, the Omni-directional mode the gain is also reduced in the low frequency bands. This allows a not always sufficient reduction of unpleasant noise achieve.

A similar hearing aid is, for example, from document <patcit id="pcit0001" dnum="WO03059010A1"><text>WO 03/059010 A1</text></patcit> known. This instrument has two microphones that have different sensitivity to wind noise. The wind noise level of one of the microphones is recorded and based on this signal it is determined which is to provide the input signal for further signal processing of the two microphones. However, it can not be ensured if the microphone with the principle lower wind speed in the concrete situation actually provides less wind noise signal.

Furthermore, from document <patcit id="pcit0002" dnum="EP1196009A2"><text>EP 1196009 A2</text></patcit> discloses a hearing aid with adaptive adjustment of the input transducer. For example, if the wind is detected, not only the converter, but also for example the signal filtering are adjusted. Concretely, it is proposed that is switched from the directional mode into the omnidirectional mode when a wind noise is detected.

Furthermore, from document <patcit id="pcit0003" dnum="WO2004103020A1"><text>WO 2004/103020 A1</text></patcit> known to provide a hearing aid with an additional microphone which is sheltered from wind influences. Accordingly, the insular against wind microphone can be used as an input transducer for detection of wind noise.

Finally, from the publication <patcit id="pcit0004" dnum="US20020037088A1"><text>US 2002/0037088 A1</text></patcit> known to disable the occurrence of wind noise, one or more microphones.

The object of the present invention is thus to reduce the sensitivity of hearing aids to spurious Wind on.

This object is achieved by a hearing aid with a microphone device with multiple microphones, a noise detecting means for detecting a load caused by wind noise and outputting a corresponding detection signal and a signal processing device for controlling the microphone device in response to the detection signal, by the noise detection means each have a noise level is detectable by at least two of the plurality of microphones, and in the signal processing device, the at least two noise level comparable to each other and to a corresponding drive signal can be output to the microphone device.

In addition, the invention provides a method for controlling a plurality of microphones of a hearing aid by detecting a load caused by wind noise, and outputting a corresponding detection signal, and driving the plurality of microphones in response to the detection signal, wherein a respective noise level of at least two of the plurality of microphones is detected, at least two noise level compared and the microphones are activated in accordance with the comparison result.

The invention is based on the idea of ​​measuring the load caused by wind actual noise level at several microphones of the hearing aid and which to control dependent microphones. This is the wind noise intensity as it is actually given, measured at several points and hearing aids controlled the hearing aid accordingly.

Preferably the drive signal is a signal for driving the microphones in an omnidirectional mode. By this measure, an increase in the signal-to-noise ratio can be achieved.

Moreover, it is advantageous if the Rauschdektionseinrichtung the caused in particular by wind noise is constantly detected and the microphones are accordingly continuously controlled by the signal processing device. Thus, the microphones can be depending on the situation controlled and switched.

According to a particular embodiment of the inventive hearing device microphone with the lowest noise level is determined by the signal processing device seen this microphone used for omnidirectional and / the other microphones switched off. This can be for signal processing only the one microphone use, which is the least affected by the wind.

Moreover, the signal processing means may comprise a classifier to select the / of the microphones for further signal processing based on the noise level. In this way, the microphones can purposefully switch to the appropriate mode.

The present invention will now be explained in more detail with reference to the accompanying drawings, in which:<dl id="dl0001"><dt>1 shows</dt><dd>the wind-induced response at three microphones of a hearing aid;</dd><dt>FIG 2</dt><dd>a schematic diagram of an inventive hearing device.</dd></dl>

The detail below described embodiment is a preferred embodiment of the present invention.

Directional hearing aids have multiple microphones, the functional reasons do not have their outlet opening at the same location of the hearing. Therefore, the outlet openings when the hearing aid is worn, not even to the ear of the wearer at the same location of the head and the pinna. Consequently show the individual microphones, as shown in FIG 1, a different wind speed depending on the position at the ear and of course also on the shape of the pinna. In the present example (two to three microphones) detected by the microphone array in the hearing aid not only the wind but also measured simultaneously by internal power meter each frequency-specific wind noise. According to FIG 1 is obtained for a first microphone, a first noise spectrum R1, a second microphone, a second noise spectrum R2 and a third microphone a third noise spectrum R3. The level of the third noise spectrum R3 of the third microphone is located here in all spectral regions below the noise levels of the other two microphones. A similar comparison would therefore lead to the conclusion that the third microphone is least affected by the wind in the entire spectral range. Accordingly, it should be used in the current situation as the sole omnidirectional microphone.

From FIG 1 is further seen that the noise spectrum R2 is higher than the noise spectrum R1 and the higher frequency range lower than this in the medium frequency range. If a hearing aid equipped with only these two microphones, these two microphones could be switched to the current wind situation so that the second microphone in the low and mid frequency range and the first microphone in the higher frequency range serves as Omnidirektionalmikrofon. This means that the microphones are driven or switched frequency specific to the wind situation.

The comparison of the level spectra can for example take place by means of adjustable thresholds. With the help of a classifier can then select the more suitable for wind situation omni-directional microphone signal or a combination of microphone signals (z. B. the sum of two or three microphone signals). Thus, a further reduction of the wind noise can adaptively induced pseudo sound effect depending on the wind speed / turbulence intensity and location of the microphones on the head. Measurements of the head with a winch assembly for speeds up to 20 km / h showed that in addition to the above measures (automatic switching of Direktional- in omnidirectional mode and reducing the gain at lower frequencies) by optionally frequency-selective choice of each lower-noise omnidirectional microphone more improvements can be up to 15 dB can be achieved.

The basic structure of a hearing device according to the invention is shown in FIG. 2 Accordingly, the hearing aid has three microphones M1, M2 and M3. The noise signals of all three microphones M1, M2 and M3 are measured in a level meter P. A downstream comparator C compares the level spectra optionally with certain thresholds. A subsequent classifier K decides based on comparisons which microphone to be used for signal processing in the hearing aid as an input signal converter. Controlled by the signal from the classifier K switches a multiplexer M with the corresponding signal for the omnidirectional mode for further signal processing.

In parallel, notes a wind detector W, whether there is a wind noise on the microphones. Only if wind is detected, the multiplexer M is activated and it is the more appropriate microphone optionally switched through a frequency-specific. however no wind is detected, the signals of all microphones for obtaining a directional effect may be used. It may also be useful to have a pure omni-directional signal, formed of signals of M1 or any combination of M1 and Mn to switch to a reduced wind omni-directional signal from another microphone M2 or M3.