EP1519626A2 - Procédé et dispositif pour le traitement d'un signal acoustique - Google Patents

Procédé et dispositif pour le traitement d'un signal acoustique Download PDF

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EP1519626A2
EP1519626A2 EP04405754A EP04405754A EP1519626A2 EP 1519626 A2 EP1519626 A2 EP 1519626A2 EP 04405754 A EP04405754 A EP 04405754A EP 04405754 A EP04405754 A EP 04405754A EP 1519626 A2 EP1519626 A2 EP 1519626A2
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Prior art keywords
signal
frequency band
wind noise
input
stage
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German (de)
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EP1519626A3 (fr
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Henry Luo
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Sonova Holding AG
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Phonak AG
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
    • H04R25/50—Customised settings for obtaining desired overall acoustical characteristics
    • H04R25/505—Customised settings for obtaining desired overall acoustical characteristics using digital signal processing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R25/00—Deaf-aid sets, i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception
    • H04R25/50—Customised settings for obtaining desired overall acoustical characteristics
    • H04R25/502—Customised settings for obtaining desired overall acoustical characteristics using analog signal processing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2410/00—Microphones
    • H04R2410/07—Mechanical or electrical reduction of wind noise generated by wind passing a microphone

Definitions

  • This invention is in the field of processing signals in or for hearing instruments. It more particularly relates to a method of converting an acoustic input signal into an output signal, a hearing instrument, and to a method of manufacturing a hearing instrument.
  • Wind exists in different speeds and intensities and may vary significantly over time.
  • the action of the wind directly on the hearing aid and on objects in its immediate vicinity can cause a variety of undesirable audible effects. These effects are usually referred to as wind noise.
  • Wind noise is a severe problem for users of hearing aids.
  • wind noise levels are low or medium, wind noise can mask some speech signals and the hearing aid user usually experiences decreased speech discrimination.
  • the noise level in the hearing aid can be very high, possibly in excess of 100 dB SPL.
  • wind can saturate the microphone, thereby causing extremely high noise levels and discomfort for the hearing aid user. Users therefore often switch their device off in windy conditions, since in windy surroundings acoustical perception with the hearing device switched on may become worse than if the hearing device is switched off.
  • wind noise exhibits properties and features also common to other noise signals encountered in daily life. Also, depending on wind speed, direction of the wind with respect to the device, hair length of the individual, mechanical obstructions like hats and other factors, magnitude and spectral content of wind noise vary significantly. For these reasons it is often difficult to uniquely classify the presence of wind noise and extract it from other environmental noises.
  • Wind noise does also have several unique characteristics that facilitate its detection. Wind noise predominantly is a low-frequency phenomenon. Many of the available wind noise detection technologies make use of the low correlation between two spatially separated microphones or make use of the unique spectral patterns exhibited by wind noise.
  • a known wind noise detection method detects wind noise by computing the correlation between signals produced by two microphones, as disclosed in US2002/037088.
  • a low correlation between the outputs from two different microphones can at times be applied to reliably detect the presence of wind noise.
  • the correlation of wind noise created at different sources differs.
  • Turbulence created at microphone ports causes signals with a low correlation.
  • the resulting wind noise signals at the microphones may be highly correlated.
  • a second wind noise detection technique is based on the signal from a single microphone. This method makes use of several well know wind noise properties: high magnitudes, low auto-correlation, and energy content at very low frequencies. Such a method is disclosed in EP 1 339 256. In a further development, also disclosed in EP 1 339 256, pitch filtering and nonlinear filtering have been developed to minimize the attenuation of the speech target signal.
  • a wind noise reduction technique disclosed in US2002/037088 for hearing devices with more than one microphone, is to switch the hearing aid from a two microphone directional, or beamforming, mode to a single microphone or omnidirectional mode (sometimes referred to as omni mode) when wind noise is detected.
  • This technique may be combined by the mentioned approach of applying a high-pass filter when switching from the directional to the omnidirectional mode.
  • WO 03/059010 discloses a method that uses two omni microphones in a hearing aid for the purpose of achieving a wind noise insensitive hearing aid. This disclosure describes the use of two microphones with different wind noise sensitivities. When wind noise is detected, the signal from the microphone with the lower wind noise sensitivity is used as the hearing aid input signal.
  • wind noise reduction may be achieved by reducing the low frequency gain in the frequency domain or by applying a highpass filter in the time domain, as disclosed in EP 1 339 256.
  • the methods should be computationally not expensive, so that they may be implemented also in hearing devices with limited processing power.
  • the methods should not be dependent on the signal correlation as a major indicator for the presence of wind noise and therefore, in the case of more than one microphone, be equally suited for wind noise caused at the microphone ports and for the wind noise caused by other objects.
  • a converted acoustic signal is processed in a number of frequency bands, a low frequency band of which is chosen to be a master band.
  • a wind noise attenuation value is determined in each frequency band, based on a signal level in the frequency band concerned and on a signal level in the master band.
  • a method of processing a time dependent electric signal being a converted acoustic signal into a processed electric signal comprising the steps of
  • frequency band attenuation In the case of low levels of detected wind noise ⁇ i.e. depending on the frequency band indicator value ⁇ the frequency band attenuation will be zero. Positive frequency band attenuation here is used for any processing step in the frequency band that reduces the output signal level compared to the situation where no wind noise would be present. Often, frequency band attenuation will be implemented in the form of a frequency band specific gain reduction.
  • the chosen course of action is based on the insight that wind noise is predominantly a low frequency phenomenon. This helps to discriminate wind noise from other sounds, namely by using the - low frequency - master band indicator value next to the indicator value of the frequency concerned for the computation of a frequency band specific attenuation.
  • the frequency band indicator value is computed based on a comparison with a level threshold: In each frequency band, the time duration of the averaged signal being above a level threshold in a certain time interval is measured.
  • the band indicator value is chosen to be a first figure such as "one" (or “wind is detected") if the duration is above a duration threshold and a second figure such as "zero" (“no wind”) if the duration is below said duration threshold.
  • the band indicator value is chosen to be said time duration value (possibly multiplied by a constant).
  • the band indicator value is chosen to be a weighted time duration, for example the difference between the signal and the level threshold integrated over the time sections in which the signal is higher than the level threshold.
  • the frequency band attenuation may be chosen to be proportional to the frequency band indicator value if the master band indicator is indicative of wind noise (first variant), or if both the frequency band indicator value and the master band indicator value exceed a certain master band threshold (second and third variant), respectively, and zero otherwise (zero meaning here that no specific attenuation is applied at this signal processing stage). It may, however, also be a more complex function of the frequency band indicator value and the master band indicator value, and/or may further depend on the signal level in the frequency band.
  • the time duration value may simply be determined by counting signals above the level threshold.
  • a frequency band wind noise comparator may generate a positive value such as +1 if the current, preferably averaged, signal is higher than the level threshold. It may generate a negative value such as -1 if the signal is below the level threshold.
  • a wind noise counter will integrate the results from the wind noise comparator in a run-time mode. Only if the output from the wind noise counter is higher than a pre-determined threshold value will the wind noise detector indicate the presence of wind noise in that frequency band, i.e. yield a non-zero indicator value.
  • the computation of the frequency band indicator value includes computing a signal index, said signal index computation being performed by determining at least one of a change in intensity sub-index, an intensity modulation frequency sub-index and of a time duration sub-index and by computing said signal index from said sub-index or sub-indices, respectively.
  • the signal index computation may more concretely be carried out in the manner exposed in US 2002/0191804, especially in paragraphs [0048] to [0050], [0053] to [0054] and [0062] referring to Fig.
  • the method comprises, previous to the evaluation of the frequency band indicator value, the step of determining an average of two converted acoustic signals.
  • These two converted signals may be, according to a first variant, acoustic signals obtained from two or more different microphones. They may be, according to a second variant, a signal from one microphone and said signal delayed by a delay time ⁇ .
  • Further signal processing steps may be applied before and/or after the evaluation of the frequency band attenuation, or may be applied in parallel thereto.
  • the further signal processing steps may comprise any signal processing algorithms known for hearing aids or yet to be developed. For obtaining an acoustic output signal, the processed electric signal is transformed back to the time domain.
  • the invention also proposes to use the low correlation of wind noise in conjunction with other indicators. It has been found that by an averaging step between two signals, a smoother, more reliable wind noise detection may be achieved.
  • This averaging may be an averaging between output signals of at least two microphones in a first variant, so that the low spatial correlation is used, or an averaging between an output signal of a microphone and the same output signal delayed by a delay time ⁇ so as to use the low correlation of wind noise along time.
  • a method of reducing disturbances, especially wind disturbances, in a hearing device comprising the steps of providing a first electric signal being obtained from an acoustic signal, of providing a second electric signal being obtained from an acoustic signal, of determining an average of said first and second electric signals, and of using said average as in input signal for a wind noise detecting stage.
  • a wind noise reducing effect according to the first variant of the second aspect of the invention may be achieved in hearing instruments with at least two microphones where in the presence of wind noise the instrument may be switched from a directional mode to a omnidirectional mode in which an average of the output signals of the two microphones is used as signal.
  • An especially preferred embodiment of the second aspect of the invention is the combination with the first aspect of the invention.
  • the averaging according to the second aspect of the invention results in a more reliable wind noise detection according to the first aspect of the invention if wind noise detection is based on the intensity level over threshold over time.
  • a method of processing a time dependent electric signal comprising the steps of
  • the third aspect of the invention may be, according to a preferred embodiment, combined with the second aspect of the invention.
  • the combination of the first and/or the third aspect of the invention with the second aspect of the invention features the considerable advantage that both, characteristic wind noise features concerning the spatial and/or temporal correlation and spectral features are used as indicators and that nevertheless the method is computationally not expensive.
  • the computation of the frequency band indicator value may include computing a signal index as disclosed in US 2002/0191804, i.e. also in embodiments of the third aspect, the technique described in US 2002/0191804 may be used to confirm the detection of wind noise based on its characteristic intensity change, modulation, and/or duration characteristics.
  • the invention also features acoustical devices, especially hearing devices, implementing the methods according to the aspects of the invention and methods for manufacturing such acoustical devices.
  • hearing instrument or “hearing device”, as understood here, denotes on the one hand hearing aid devices that are therapeutic devices improving the hearing ability of individuals, primarily according to diagnostic results.
  • Such hearing aid devices may be Behind-The-Ear hearing aid devices or In-The-Ear hearing aid devices (including the so called In-The-Canal and Completely-In-The-Canal hearing devices).
  • the term stands for devices which may improve the hearing of individuals with normal hearing e.g. in specific acoustical situations as in a very noisy environment or in concert halls, or which may even be used in context with remote communication or with audio listening, for instance as provided by headphones.
  • the hearing devices addressed by the present invention are so-called active hearing devices which comprise at the input side at least one acoustical to electrical converter, such as a microphone, at the output side at least one electrical to acoustical converter, such as a loudspeaker, and which further comprise a signal processing unit for processing signals according to the output signals of the acoustical to electrical converter and for generating output signals to the electrical input of the electrical to mechanical output converter.
  • the signal processing circuit may be an analog, digital or hybrid analog-digital circuit, and may be implemented with discrete electronic components, integrated circuits, or a combination of both.
  • a hearing aid system with a single microphone is schematically illustrated in Fig. 1.
  • the system comprises, in a sequence, a microphone 1, an analogue-to-digital converter 2, producing an input signal, a digital signal processing stage (DSP) 3, transforming the input signal into an output signal, a digital-to-analog converter 4 and a receiver 5.
  • a dual microphone hearing aid system as illustrated in Fig. 2 differs therefrom in that two microphones 1.1, 1.2 and accordingly two analog-to-digital converters 2.1, 2.2 are present.
  • dual microphone aids there are many different modes such as omni, dual-omni, fixed beamformer and adaptive beamformer.
  • the shown embodiment in addition comprises a telecoil 6 and a multiplexer 7, which is controlled by the DSP 3 and receives the output signals of both, the second microphone 1.2 and the telecoil.
  • the output from the multiplexer is either the microphone 1.2 signal or the telecoil 6 signal.
  • a scheme of embodiments of the first and third aspect of the invention is schematically illustrated in Fig. 3 .
  • the sound input, a mixture of signal and noise is first acquired by a microphone 1 or by a plurality of microphones. Then, it is converted into a digital format by at least one A/D converter 2 so as to obtain an input signal S I for the digital signal processing unit.
  • the digital input may then be framed and windowed with a low-pass filter of length L.
  • the windowed low-pass filter such as a Hamming Window is used to separate one band of frequencies from another and to remove the high frequency noise.
  • the resulting windowed time segment of data may also be folded and added to generate a block of data, which is then converted from the time domain to the frequency domain, via, for example, a 2N-point fast Fourier transform (FFT) or by bandpass filters in the time-to-frequency transformation stage 11.
  • FFT fast Fourier transform
  • the coefficients of the 2N-point FFT represent N frequency bands which are used to calculate the signal strength of the band in the frequency domain.
  • the strength of the input signal also called 'signal level' in this text
  • the signal in each frequency band is processed by a frequency band specific wind noise detector.
  • Adaptive noise reduction 12 according to US 2002/0191804 in the shown embodiment is applied in parallel with wind noise reduction according to the first aspect of the invention.
  • Low-level wind noise for example ⁇ 50 dB SPL
  • a set amount e.g., an amount between 6 dB and 12 dB
  • wind noise management 13 is activated.
  • the adaptive noise reduction of US 2002/0191804 may then optionally control or confirm wind noise detection, as indicated by the arrow 14.
  • further processing stages 15 ⁇ potentially including processing stages upstream of the wind noise management unit and/or between wind noise management processing steps ⁇ hearing loss correction according to the state of the art or according to methods yet to be developed is applied.
  • a frequency-domain-to-time-domain transformation stage 16 is also illustrated in the figure.
  • each frequency band comprises a frequency band specific wind noise reduction stage 22.1, ..., 22.n.
  • a low frequency band ⁇ usually the frequency band covering the lowest audible frequencies ⁇ is chosen to be the master band.
  • the evaluated wind noise indicator value of the master band is ⁇ together with the wind noise indicator value of the frequency band concerned ⁇ used for determining the attenuation level in the frequency band. For example, noise detected in this frequency band is only confirmed to be wind noise if wind noise is also detected in the master band. This influence of the master band is indicated by an arrow 23 in Fig. 4.
  • the attenuation value evaluated by the wind noise reduction stage 22.1, ... 22.n is applied on the frequency band input signal, as illustrated by the multipliers 24.1, ..., 24.n.
  • Fig. 5 shows the wind noise detection in a frequency band.
  • Two stages of a first order averager are implemented in each frequency band.
  • the signal S ( f ) in the frequency band f is first processed to produce a fast first order average, as has been implemented for signal detection in the adaptive noise reduction method of US 2002/0191804.
  • the parameter ⁇ is a function of the time constant ⁇ for the first order averager.
  • ⁇ 1- e -1 ⁇
  • the fast first order averager 31 has a short time constant (preferably between 1 ms and 10 ms, for example between 5 ms and 7 ms) in order to accurately track the fast changes of real-life signals for signal and noise detection.
  • the fast first order averager is followed by a slow first order averager 32.
  • the slow first order averager is used to compute the long-term signal level in the frequency band, and has a much longer time constant (preferably between 50 ms and 1500 ms, especially preferred between 200 ms and 1000 ms, for example between 500 ms and 700 ms).
  • the signal level Y ( f ) after the slow first order averager is compared with a level threshold value T ⁇ being a wind noise level threshold ⁇ to determine whether the signal is higher or lower than the wind noise threshold. If the level is higher than the level threshold, the wind noise comparator 33 will generate a positive value such as +1. If the level is at or below the threshold, the comparator will generate a negative value such as -1.
  • a wind noise counter 34 will integrate the results from the wind noise comparator 33 in run-time mode. Only if the output from the wind noise counter is higher than a pre-determined count threshold value, will the wind noise detector indicate the presence of wind noise and process the signal as wind noise in that frequency band. This is illustrated by a count threshold comparing unit 35.
  • the count threshold value may for example be 0 or another fixed value. If the output of the wind noise counter is lower than the count threshold value, wind noise is not indicated and the signal is processed as a general signal. In this embodiment, a frequency band indicator value therefore assumes a value "1" (corresponding to "wind noise detected") or a value "0" (corresponding to "no wind noise”).
  • wind noise detection includes using the detection method of US 2002/0191804:
  • the signal X ( f ) produced by the fast averager 31 is used by a signal index computing unit 36 to determine a signal index 37 based on at least one of the change of intensity, the modulation frequency and of the signal time duration. Only if the signal index is below (or above, depending on the chosen sign convention) a certain value will wind noise be confirmed (box 38).
  • the input signal in a following step is subject to wind noise dependent attenuation.
  • the signal index is used to verify a wind noise count determined according to the first embodiment.
  • the frequency band indicator value may be chosen to be a function of both, a wind noise duration and the signal index.
  • the indicator value is set to be the signal index.
  • the attenuation value is chosen to be a function of the signal index of the frequency band concerned and of the master band. For example, if the signal index is determined as in US 2002/0191804 to be maximal in a change-of-intensity, modulation-frequency and/or time-duration-range where the desired speech and music may be expected, the attenuation value may be proportional to the negative of the frequency band signal index plus a constant value or to the negative of the master band signal index plus a constant value, whichever is smaller.
  • the first stage wind noise detection in a frequency band is further considered together with the results from the master band.
  • the signal may, in a further processing step, be processed using the noise reduction method of US 2002/0191804. This may be done whether or not wind noise has been detected and will be explained further below in somewhat more detail.
  • the noise reduction method may be used for confirming a wind noise detection result and/or it may be used independently of the wind noise detection and attenuation by being applied to the signal and thus by reducing wind noise in the manner every other type of noise is reduced.
  • Each frequency band can have its own time constants for the fast and slow first order filters, its independent level threshold value, and possibly also its independent count threshold value.
  • the level threshold values of an example of the invention are illustrated in Fig. 6 .
  • Fig 6 shows the level threshold for a wind noise detection scheme including five frequency bands B0-B4.
  • the wind noise is located primarily in the low frequency region of the audio spectrum. Therefore, in the embodiment of Fig. 6, the wind noise detection concentrates on the low frequency region below 2 kHz, although the method does not necessarily need to be restricted to only the five bands shown in Fig. 6. Rather, often more than five frequency bands will be used.
  • the band concentrated around 125 Hz is the master band being the frequency band that contains a dominant proportion of the wind noise energy.
  • the level threshold in the embodiment of the figure decreases with increasing frequency.
  • each frequency band can optionally have, in the case of combination with the noise reduction method, its own signal index according to its frequency characteristics.
  • wind noise reduction (being a for example frequency band specific attenuation) is applied to suppress wind noise instantaneously.
  • the resulting signal is then supplied to the hearing loss correction component of the hearing instrument, where it may be filtered and amplified as required, whereupon it will be converted back to the time domain and converted to a sound signal.
  • the transformation of the signal between the time domain and the frequency domain can also be performed with other methods than FFT, for example with bandpass filters or with wavelet transforms.
  • Fig. 7 illustrates fixed wind noise reduction. If the noise level is above the level threshold (i.e. if the output of the counter in the frequency band is above the count threshold) and this also applies to the master band, the noise level in the frequency band is reduced by a fixed attenuation value.
  • a fixed attenuation value may be between 3 dB and 30 dB, preferably between 6 dB and 18 dB, for example 6 dB or 12 dB.
  • the attenuation value may be selected by the user.
  • This fixed wind noise reduction helps to improve speech intelligibility and comfort with low or medium wind noise.
  • wind noise becomes very strong, such a wind noise reduction does not sufficiently reduce the strong wind noise levels which may still completely mask the speech signal or cause microphone saturation and considerable discomfort to the user. Therefore, for different wind speeds causing different wind noise levels, the fixed wind noise reduction may not be sufficient in a frequency band and overly aggressive in another band.
  • the wind noise level or pattern will change in different frequency regions. This can result in changes of wind noise level detected by wind noise detection. Such a change in wind noise detection can cause the wind noise reduction to be enabled or disabled in some frequency bands over time.
  • an adaptive wind noise reduction strategy is proposed according to a second embodiment.
  • the logic is that if wind noise over a certain level can be reliably detected and identified as wind noise in specific frequency bands- this detection and identification may be accomplished by the above described wind noise detection method ⁇ a stronger wind noise can be treated differently than a lower level wind noise.
  • the actual wind noise reduction rule may be: the stronger the wind noise level, the more aggressive the wind noise reduction. This is illustrated in Figs. 8, 9, and 10.
  • Fig. 8 shows noise levels caused by strong wind 41, medium wind 42 and low wind 43, respectively, as a function of the frequency.
  • the level threshold 44 is a function of the frequency. In practice, the noise levels and the level threshold may be considered as discrete functions of the frequency, namely to provide a different specific value in each band.
  • the strong, medium and low wind levels have different border frequencies f S , f M , and f L which are the maximum frequencies for which the signal is attenuated.
  • the attenuation as a function of the frequency for the noise level of Fig. 8 is shown in Fig. 9.
  • the actual (wind) noise level L ( f ) may, for example, be obtained from the output Y ( f ) of the slow averager 32 shown in Fig. 5.
  • the noise canceling system of US 2002/0191804 may be used to confirm wind noise in a frequency band, or, more in general, to evaluate a frequency band indicator value.
  • An other aspect of applying the mentioned noise canceling system in the context of wind noise canceling is briefly described with reference to Fig. 10 .
  • the noise cancelling system NC can detect wind noise and therefore apply adaptive noise reduction accordingly.
  • NC can detect and attenuate wind noise with the same effectiveness as it attenuates any other stationary or pseudo-stationary noises as described in US 2002/0191804.
  • NC may contribute additional noise reduction for all levels of wind noise.
  • NC will reduce wind noise with notable improvement as it does for other types of noise.
  • NC as described in US 2002/0191804 does not offer enough wind noise reduction.
  • the combination with the above described adaptive wind noise reduction does, as is illustrated in Fig. 10.
  • Each frequency band can have a different wind noise reduction scheme depending on the wind noise level in that frequency band, thereby achieving a combined reduction from both NC and (adaptive) wind noise reduction.
  • the actual reduction will follow the following rules in any frequency band:
  • Each frequency band can have a different attenuation scheme from either NC or wind noise management according to the first aspect of the invention, which will create different overall wind noise reduction in each band. Therefore, the wind noise management benefit can be optimized for different users with different hearing losses and different daily life styles. If the wearer of the hearing aid is exposed to a wide open windy environment such as a golf course, the wearer may want to have a very aggressive and powerful wind noise reduction scheme. If a person lives in a city or an environment without strong winds, the person may just want to use a moderate wind noise reduction scheme. Therefore, the flexible wind noise reduction scheme invented here can bring the optimized benefit of intelligibility and comfort improvements for different people in widely different environments. This results in a personalized adaptive wind noise management for individual hearing loss and life style.
  • a method of reducing disturbances, especially wind disturbances, in a hearing device is provided.
  • This aspect is based on the fact that the wind noise signals, being mainly caused by turbulences, are highly random.
  • a first embodiment of the second aspect concerns a hearing aid comprising at least two microphones, preferably omnidirectional microphones.
  • the case of two microphones is described, however, this first embodiment of the second aspect of the invention also works for systems comprising more than two microphones.
  • the hearing aid is switched from a two microphone directional, or beamforming, mode to a single microphone or omnidirectional mode when wind noise is detected.
  • Some additional wind noise reduction might be achieved by applying a highpass filter when switching from the directional to the omnidirectional mode:
  • the figure, next to an averager 71 also shows a switch 72 for switching between the averaged signal produced by the averager and the signal S d obtained conventionally in a directional mode.
  • wind signals can not be treated as plain wave signals.
  • the switching from a directional mode to this omnidirectional averaging mode may be done manually by the user or automatically upon detection of wind noise.
  • the wind noise detection method in accordance with the first aspect of the invention may be used.
  • the averaging of the two microphone input signals can be done with the raw analogue or digitized input signal or, as an alternative, can be done in frequency bands.
  • the at least two microphones of a hearing aid implementing the method according to the second aspect are preferably omnidirectional microphones.
  • the case of two microphones is described, however, the second aspect of the invention also works for systems comprising more than two microphones.
  • the typical delay time should be around 125 ⁇ s in order to again use the low correlation of wind noise without affecting the desired acoustic signals like speech or music.
  • a delay less than 125 ⁇ s may be chosen. More generally, as a delay time ⁇ , a value between 40 ⁇ s and 100 ⁇ s, especially between 60 ⁇ s and 90 ⁇ s is preferred. Most preferred are delay times below 83 ⁇ s, such that a first notch is beyond 6 kHz. The effect of the approach according to this embodiment decreases if the delay time is reduced below 40 ⁇ s.
  • the second aspect of the invention as illustrated in Figs. 11 and 12, is combined with the first aspect.
  • That determination of s(t) will produce a signal with reduced intensity level changes as a function of time.
  • This smoothing of the signal s(t) results in a very suitable input signal for the method according to the first aspect of this invention making wind noise detection more reliable.
  • the processing stage shown in Fig. 11 or the processing stage of Fig. 12 will be arranged between the A/D converting stage(s) 2; 2.1, 2.2 and the frequency-to-time-domain-converting stage 11.
  • its input(s) will be operationally connected to the output of the A/D converting stage(s), and its output will be operationally connected to the input of the frequency-to-time-domain-converting stage 11.
  • the signal processing unit does not have to be physically one unit, such as a single microprocessor but may comprise several elements processing the analog and/or digital signal, such as microprocessors, integrated circuits, Analog-to-Digital- and Digital-to-Analog-converters, filter banks, passive elements etc.
  • the methods according to the invention may be combined with state-of-the-art methods of reducing wind noise, for example with high-pass filtering or a method disclosed in EP 1 339 256.

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Neurosurgery (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
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EP04405754A 2004-12-07 2004-12-07 Procédé et dispositif pour le traitement d'un signal acoustique Withdrawn EP1519626A3 (fr)

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EP1744591A2 (fr) * 2005-07-11 2007-01-17 Siemens Audiologische Technik GmbH Prothèse auditive avec sensibilité réduite au vent et procédé correspondant
EP1750483A1 (fr) 2005-08-02 2007-02-07 GN ReSound A/S Prothèse auditive avec suppression de bruit de vent
WO2008041730A1 (fr) * 2006-09-29 2008-04-10 Panasonic Corporation Procédé et système permettant de détecter le bruit du vent
WO2013164029A1 (fr) 2012-05-03 2013-11-07 Telefonaktiebolaget L M Ericsson (Publ) Détection de bruit de vent dans un signal audio
WO2014048492A1 (fr) 2012-09-28 2014-04-03 Phonak Ag Méthode de fonctionnement d'un système auditif binaural et système auditif binaural
EP2919485A1 (fr) * 2014-03-12 2015-09-16 Siemens Medical Instruments Pte. Ltd. Transmission d'un signal à bruits de vent réduits à temps de latence diminué
DE102015204253A1 (de) * 2015-03-10 2016-09-15 Sivantos Pte. Ltd. Verfahren zur frequenzabhängigen Rauschunterdrückung eines Eingangssignals sowie Hörgerät
US10586523B1 (en) 2019-03-29 2020-03-10 Sonova Ag Hearing device with active noise control based on wind noise
GB2609303A (en) * 2021-07-26 2023-02-01 Cirrus Logic Int Semiconductor Ltd Single-microphone wind detector for audio device
EP4418689A1 (fr) * 2023-02-17 2024-08-21 Oticon A/s Prothèse auditive comprenant une réduction du bruit du vent

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EP1450354A1 (fr) * 2003-02-21 2004-08-25 Harman Becker Automotive Systems-Wavemakers, Inc. Dispositif de suppression de bruits de vent

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EP1450354A1 (fr) * 2003-02-21 2004-08-25 Harman Becker Automotive Systems-Wavemakers, Inc. Dispositif de suppression de bruits de vent

Cited By (19)

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US7813517B2 (en) 2005-07-11 2010-10-12 Siemens Audiologische Technik Gmbh Hearing aid with reduced wind sensitivity and corresponding method
EP1744591A2 (fr) * 2005-07-11 2007-01-17 Siemens Audiologische Technik GmbH Prothèse auditive avec sensibilité réduite au vent et procédé correspondant
EP1750483A1 (fr) 2005-08-02 2007-02-07 GN ReSound A/S Prothèse auditive avec suppression de bruit de vent
US8019103B2 (en) 2005-08-02 2011-09-13 Gn Resound A/S Hearing aid with suppression of wind noise
WO2008041730A1 (fr) * 2006-09-29 2008-04-10 Panasonic Corporation Procédé et système permettant de détecter le bruit du vent
US8065115B2 (en) 2006-09-29 2011-11-22 Panasonic Corporation Method and system for identifying audible noise as wind noise in a hearing aid apparatus
WO2013164029A1 (fr) 2012-05-03 2013-11-07 Telefonaktiebolaget L M Ericsson (Publ) Détection de bruit de vent dans un signal audio
US9456286B2 (en) 2012-09-28 2016-09-27 Sonova Ag Method for operating a binaural hearing system and binaural hearing system
WO2014048492A1 (fr) 2012-09-28 2014-04-03 Phonak Ag Méthode de fonctionnement d'un système auditif binaural et système auditif binaural
EP2919485A1 (fr) * 2014-03-12 2015-09-16 Siemens Medical Instruments Pte. Ltd. Transmission d'un signal à bruits de vent réduits à temps de latence diminué
US9584907B2 (en) 2014-03-12 2017-02-28 Sivantos Pte. Ltd. Transmission of a wind-reduced signal with reduced latency time
DE102015204253A1 (de) * 2015-03-10 2016-09-15 Sivantos Pte. Ltd. Verfahren zur frequenzabhängigen Rauschunterdrückung eines Eingangssignals sowie Hörgerät
DE102015204253B4 (de) * 2015-03-10 2016-11-10 Sivantos Pte. Ltd. Verfahren zur frequenzabhängigen Rauschunterdrückung eines Eingangssignals sowie Hörgerät
US10225667B2 (en) 2015-03-10 2019-03-05 Sivantos Pte. Ltd. Method and hearing aid for frequency-dependent reduction of noise in an input signal
US10586523B1 (en) 2019-03-29 2020-03-10 Sonova Ag Hearing device with active noise control based on wind noise
EP3716652A1 (fr) 2019-03-29 2020-09-30 Sonova AG Dispositif d'aide auditive avec contrôle actif du bruit basé sur le bruit du vent
GB2609303A (en) * 2021-07-26 2023-02-01 Cirrus Logic Int Semiconductor Ltd Single-microphone wind detector for audio device
GB2609303B (en) * 2021-07-26 2023-09-20 Cirrus Logic Int Semiconductor Ltd Single-microphone wind detection for audio device
EP4418689A1 (fr) * 2023-02-17 2024-08-21 Oticon A/s Prothèse auditive comprenant une réduction du bruit du vent

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