Cochlear implants and cochlear implant systems

Abstract

The present application discloses a cochlear implant and a cochlear implant system, wherein the cochlear implant includes: at least one input transducer for capturing incoming sound and for generating an electrical audio signal in a frequency band representing the incoming sound; a sound processor configured to analyze and process the electrical audio signal; a transmitter for transmitting the processed electrical audio signal; a receiver / stimulator that receives the processed electrical audio signal from the transmitter and converts the processed electrical audio signal into electrical pulses; an electrode array suitable for implantation in the cochlea, comprising a plurality of electrodes for stimulating the cochlear nerve with the electrical pulses; and a control unit configured to control the distribution of the electrical pulses to the plurality of electrodes; wherein the control unit is configured to distribute the electrical pulses to the plurality of electrodes by applying one of a plurality of different encoding schemes.

Description

[0001] This application is a divisional application of Chinese patent application 201811528969.0, filed on December 13, 2018, with the invention name “Audio processing device, system, application and method”. Technical Field

[0002] The present invention relates to a hearing aid device configured to implement a frequency band bundling scheme and a method of processing an input audio signal. Background Art

[0003] Digital hearing aid devices typically include an input transducer, such as a microphone, to receive sound from the surrounding environment and convert the received acoustic signal into an electrical audio signal. The electrical audio input signal is a frequency-domain signal that is converted into a time-domain input signal using an analog-to-digital converter. Furthermore, the time-domain input signal is converted into multiple input frequency bands. Typically, the multiple input frequency bands are determined by an analysis filter bank, which also includes filter coefficients to provide gain to selected frequency bands, for example, based on the specific listening situation. In a processing unit, the multiple frequency bands are processed in multiple processing channels. Processing multiple frequency bands requires sufficient computing power, and thus energy, such as that provided by a battery. Ultimately, the processed frequency bands are converted into electrical audio output signals by a digital-to-analog converter. These signals are then converted into audible sound and transmitted as acoustic output signals to the user's ear using a speaker (also called a receiver). The speaker may be located in the user's ear canal. The hearing aid device described above can improve the user's auditory experience.

[0004] Typically, digital hearing aid devices can be programmed by connecting them to an external computer. This enables the implementation of additional processing features. Thus, the processing characteristics can be adjusted, for example, to amplify or suppress selected frequency bands. Sometimes, the processing characteristics can be adjusted by the user themselves according to different listening situations. Even programs that automatically and adaptively adjust the processing characteristics can be implemented. Based on such programs, for example, acoustic feedback or background noise can be adaptively reduced, or the processing of received sound signals can be automatically adapted to different listening situations. This can increase user comfort.

[0005] In order to reduce the computational effort and thus save energy, it is advantageous to bundle the input frequency bands and distribute the smaller number of frequency bands to be processed to the processing channels of the signal processing unit. After processing the smaller number of frequency bands, the processed frequency bands can be redistributed to a larger number of output frequency bands so that the resolution of the frequency bands is increased again.

[0006] EP 3122072 A1 describes an audio processing device comprising an input unit for converting a time-domain input signal into a plurality of input frequency bands and an output unit for converting a plurality of output frequency bands into a time-domain output signal. The described audio processing device aims to provide a flexible audio processing solution, for example adaptable to the characteristics of the input signal. This allows the audio processing to be adapted to specific acoustic environments and / or user needs (e.g., hearing impairment) in order to minimize power consumption and / or processing frequency resolution.

[0007] Hearing aid devices can be implemented, for example, as behind-the-ear (BTE) hearing aids, which typically have the microphone positioned behind the user's ear, or as in-the-ear (ITE) hearing aids, which typically have the microphone positioned in the user's ear. In both cases, the speaker is typically placed in the user's ear canal to stimulate the eardrum. An advantage of BTE hearing aids is that the distance between the microphone and the speaker (also known as the feedback path) is greater than that of ITE hearing aids, making BTE hearing aids less susceptible to feedback. Consequently, in BTE hearing aids, higher gain can be applied to various frequency bands without causing feedback.

[0008] In the case of a hearing aid device, such as a BTE or ITE hearing aid, that includes a directional microphone with two microphones or two sound inlets, the directional system can be configured so that the directivity pattern is targeted towards eliminating the feedback path. This means that the directional response has its minimum directivity towards the feedback path. The directivity pattern represents the directionality of the directional system.

[0009] US Pat. No. 9,351,086 B2 describes an ITE hearing aid comprising a directional microphone and a feedback suppression system that cancels acoustic feedback based on sound signals detected by two microphones or two sound inlets. The hearing aid device described comprises an "open fit" that provides ventilation. The two microphones or two sound inlets of a directional microphone (forming part of a directional system) are arranged in the ear canal on the same side of the receiver, and sound is allowed to propagate freely between the microphones or between the inlets of the directional microphone and the receiver. Preferably, the hearing aid device comprises a program (e.g., an adaptive program) for optimizing the directional system of the hearing aid device. This achieves improved feedback reduction while enabling a considerable gain to be applied to the incoming signal. Summary of the Invention

[0010] It is an object of the present invention to provide an improved hearing aid device.

[0011] According to the present invention, the aforementioned objects are achieved by a hearing aid device comprising a first input transducer configured to receive a first acoustic signal and convert the first acoustic signal into a first electrical audio signal. The input transducer may be a microphone or any other type of input transducer. The microphone may be a microphone integrated into the hearing aid device and / or a remote microphone operating wirelessly or may be a wired microphone.

[0012] The first analog-to-digital converter converts the first electrical audio signal into a first time domain input signal, and the first input unit (including the first analysis filter bank) is configured to convert the first time domain input signal into a plurality of (N I,1 The number of first input frequency bands N I,1 Determined by an analysis filter bank (e.g., a first analysis filter bank). The analysis filter bank may include filter coefficients configured to apply a gain to a selected frequency band. Obviously, a smaller gain is desirable when the frequency band has an increased likelihood of feedback occurring.

[0013] The analysis filter bank may be, for example, a linear phase filter bank designed to enable distortion-free combining (eg summing) of the frequency band signals into the channel signals.

[0014] The first frequency band bundling and allocation unit may be configured to bundle adjacent first input frequency bands and allocate the first frequency band to be processed to a plurality of (N P,1 The bundling may occur according to a bundling scheme, which may be a matrix including information on whether input frequency bands should be bundled or not.

[0015] The advantage of bundling different frequency channels is mainly to save computing power, because some calculations are valid for a wider range of frequencies.Depending on the application, different bundling schemes will be optimal.

[0016] The frequency band bundling and allocation unit is configured to perform the bundling of the input frequency bands dynamically or statically. Likewise, a mixture of static and dynamic bundling may be implemented. In the case where the frequency band bundling and allocation unit is configured to perform the bundling of the input frequency bands dynamically, the bundling may occur during use of the hearing aid device. This bundling may then be adapted to different listening situations during operation of the hearing device. In the case of static bundling of the input frequency bands, the frequency band bundling and allocation unit may be programmed such that the bundling scheme results in predetermined processing characteristics. The static frequency bundling scheme may, for example, be implemented by a hearing care professional prior to operation of the hearing aid device.

[0017] The memory unit is configured to store a first N I,1 The frequency band bundling and allocation unit may be configured to determine the solution based on the likelihood stored in the memory unit if the likelihood of feedback occurring in at least one input frequency band is stored in the memory unit.

[0018] N I,1The likelihood of feedback occurring in at least one of the input frequency bands may be determined based on a feedback detection unit. The feedback detection unit may be included in the hearing aid device. Alternatively, the feedback detection unit may be included in an external device that is connected, for example wirelessly, to the hearing aid device. The likelihood of feedback occurring in a specific frequency band (e.g., exceeding a threshold value) may be determined in a number of different ways as described in the prior art (e.g., based on correlation measurements, such as a cross-correlation between the input and output signals of the hearing aid). The likelihood of feedback occurring in a specific frequency band may, for example, be determined adaptively (during use of the hearing aid). Alternatively or additionally, the likelihood of feedback occurring in at least one of the input frequency bands may be determined in a procedure before the hearing aid is used by the user (e.g., during fitting of the hearing aid for a specific user).

[0019] Thus, if the hearing aid device includes a feedback detection unit, the hearing aid device can be further configured to continuously determine the likelihood of feedback occurring in at least one input frequency band. Thus, the content of the bundling and allocation scheme is continuously updated. In a dynamic scenario, the process of updating the bundling and allocation scheme occurs based on the continuously determined likelihood of feedback.

[0020] If the likelihood of feedback occurring in at least one input frequency band can be dynamically determined, a feedback detection unit may be further included in the hearing aid device. The frequency band bundling and allocation unit dynamically adjusts the bundling scheme based on the likelihood of feedback occurring in at least one input frequency band determined by the feedback detection unit.

[0021] If the probability of feedback occurring in at least one input frequency band is determined statically, the feedback detection unit is generally not included in the hearing aid device, but rather an external feedback detection unit. External feedback detection can be used, for example, by a hearing care professional, who uses it to detect which frequency regions or frequency bands have a high probability of feedback occurring. Thus, the hearing care professional can predetermine the bundling of the input frequency bands and the allocation of the input frequency bands to the processing channels. In this case, the bundling is static bundling. To determine the static probability of feedback occurring in at least one input frequency band, measurements of the feedback path can be taken into account. The feedback path can be measured by the hearing care professional, for example, during fitting of the hearing aid device. The measurement results can be converted into a matrix, which determines whether the input frequency bands are to be bundled. The matrix can be the bundling scheme applied.

[0022] The feedback path can be modeled using an adaptive filter. The output of the adaptive filter can be subtracted from the acoustic signal received by the microphone to cancel acoustic and / or mechanical feedback picked up by the microphone. As a result of feedback cancellation, more gain can be applied in the hearing aid. Generally, the feedback cancellation filter is adjusted based on the acoustic signal received by the microphone.

[0023] As an alternative, a semi-static approach may be applied, which may be based on feedback measurements taken during start-up of the hearing aid device.The semi-static approach has the advantage that the most critical frequencies for feedback potential depend on the current hearing aid device installation.

[0024] The signal processing unit of the hearing aid device is in multiple (N P,1 If the number of the first processing channels N is N, the first frequency band to be processed is processed in the first processing channels N. P,1 Less than the first input frequency band N I,1 Processing the input frequency band in a smaller number of processing channels can result in a reduction in computing power, thus leading to the advantageous result of energy saving during operation of the device.

[0025] In a preferred embodiment, the processing unit provides an output frequency band corresponding to the processed input frequency band. The output frequency band is combined into a digital audio output signal. Using a digital-to-analog converter, the digital audio output signal can be converted into an electrical audio output signal, which can be passed to the output transducer.

[0026] The output transducer of the hearing aid device may be configured to convert the electrical audio output signal into a user-perceivable signal, such as an acoustic output signal, which may be perceived by the user as sound. The output transducer may be a loudspeaker, a receiver, a stimulation unit of a cochlear implant, or any other type of output transducer.

[0027] According to the present invention, the first frequency band bundling and allocation unit is configured to generate a first bundling and allocation scheme, which determines the first N I,1 The first band to be processed is the first N P,1 The first bundling and allocation scheme depends on the first N I,1 The possibility of feedback occurring in at least one of the input frequency bands.

[0028] The inventors of the present application have recognized that if a frequency band has a high probability of feedback occurring, it is advantageous to have a high frequency resolution in that frequency region. This means that the input frequency bands in that frequency region are not bundled. If a frequency band has a high probability of feedback occurring, it is desirable to apply only a small gain to the corresponding frequency band, or to apply no gain to the corresponding frequency band. This allows feedback to be reduced or suppressed in a highly efficient manner. Conversely, it may be desirable to apply a higher gain to frequency bands that do not have a high probability of feedback occurring. Furthermore, frequency bands that have a low probability of feedback occurring can be bundled. This allows the input frequency bands to be processed in a smaller number of frequency bands, so that the computational effort and, therefore, the energy consumption of the hearing aid device, can be reduced.

[0029] The bundling and allocation scheme is stored in the memory unit and can be adjusted dynamically, statically or semi-statically. The bundling and allocation scheme determines a plurality of (N IWhether the frequency bands in the input frequency band should be bundled. Thus, feedback can be canceled in a very efficient manner by maintaining high frequency resolution in the frequency region including the frequency band with a high probability of feedback. At the same time, energy consumption can be reduced because the frequency bands in the frequency region including the frequency band with a low probability of feedback can be bundled.

[0030] Feedback is sometimes also referred to as howling. Alternatively, the term distance to feedback limit can be used instead of the likelihood of feedback. The term distance to feedback expresses how much gain can be applied up to the maximum permissible gain before the hearing aid device is too close to feedback or the sound quality of the acoustic output signal deteriorates. The maximum permissible gain depends on the measured feedback path and the currently applied gain.

[0031] An alternative definition of feedback potential is provided using the term gain margin, which is the amount of gain retained before feedback causes. For example, a gain margin such as 3 dB means that 3 dB more can be applied before feedback causes.

[0032] Optionally, the hearing aid device further comprises a first frequency band redistribution unit configured to P,1 processing channels are distributed to multiple (N O,1 After processing the plurality of input frequency bands in a smaller number of processing channels, the processed frequency bands are redistributed to a larger number of output frequency bands. Thus, the frequency resolution can be increased again compared to the number of processing channels.

[0033] In a preferred embodiment, the first bundling and allocation scheme is to represent N I,1 The first input frequency band and N P,1 A two-dimensional matrix of the first processing channels, where for N I,1 For each of the input frequency bands, the two-dimensional matrix includes the bundled values.

[0034] If the feedback probability is higher than a predetermined threshold, the bundling value may be, for example, zero, and the corresponding input frequency band is N P,1 and if the feedback probability is lower than a predetermined threshold, the bundling value may be, for example, 1 and the corresponding input frequency band may be in N P,1 The possibility of feedback occurring in at least one input frequency band may be detected by a feedback detection unit included in the hearing aid device or by an external feedback detection unit.

[0035] The bundle value can be between 0 and 1.

[0036] The frequency band bundling and allocation unit can be configured to dynamically adjust the number of first processing channels NP,1 and / or the number of second processing channels NP,2 during normal use of the hearing aid device. Adaptive bundling results in adaptive recalibration of the device. For example, internal level estimates depend on the bundling scheme. The levels of the frequency bands are calculated, and when two bands are added, the level increases. To prevent level fluctuations, recalibration of the levels is required. Alternatively, a fixed number of bundling schemes can be stored in the device along with the corresponding calibration values.

[0037] The bundling and allocation scheme may be a two-dimensional matrix comprising 1s and 0s, where 1s define frequency bands to be bundled and 0s define frequency bands not to be bundled. For example, a column may define processing channel N. P ,1 and row can define input frequency band N I Thus, the bundling and allocation scheme determines which input frequency bands are to be bundled and / or allocated based on the likelihood of feedback occurring in the corresponding input frequency bands.

[0038] Optionally, the signal processing unit may be configured to determine the signal processing unit for N based on the first bundling and allocation scheme. I,1 a first filter coefficient for each of the N input frequency bands, and wherein the acoustic output signal comprises the sum of the filter coefficients, each filter coefficient multiplied by N O,1 The filter coefficients are determined so that the feedback response between the microphone and the loudspeaker is minimized. Each filter coefficient includes an imaginary part and a real part. The imaginary part can be determined in such a way that the feedback response is minimized without affecting the inherent speech information or with as little distortion as possible. In the case where the hearing aid includes more than one microphone, each microphone includes its own set of input frequency bands, which are bundled, assigned to processing channels, and then processed in the signal processing unit.

[0039] The bundling is made suitable for time domain bandpass filtering by introducing complex filter coefficients into the filter bank.

[0040] Preferably, the number of Ni input frequency bands is the same as the number of No output frequency bands.

[0041] In a preferred embodiment of the present invention, the hearing aid device comprises:

[0042] - a second microphone configured to receive a second acoustic signal and convert the second acoustic signal into a second electrical audio signal;

[0043] - a second analog-to-digital converter, configured to convert the second electrical audio signal into a second time-domain input signal;

[0044] - a second input unit comprising a second analysis filter bank configured to convert the second time domain input signal into a plurality of (N I,2) second input frequency bands, wherein the number of the second input frequency bands N I,2 determined by a second analysis filter bank;

[0045] - a second frequency band bundling and allocation unit configured to bundle adjacent second input frequency bands and allocate the second frequency bands to be processed to a plurality of (N P,2 ) second processing channel;

[0046] The memory unit is configured to store a second N I,2 data on which input frequency bands of the N input frequency bands are subject to a feedback probability above a predetermined threshold; and wherein the signal processing unit is adapted to P,2 The second input frequency band to be processed is processed in the second processing channels, and the number of the second processing channels N P,2 Less than the number N of the second input frequency bands I,2 , and wherein the second frequency band bundling and allocation unit is configured to generate a second bundling and allocation scheme based on the second N I,2 The probability of feedback occurring in at least one of the input frequency bands determines the second N I,2 The bundle of input bands and the second band to be processed and the second N P,2 The first and second microphones generate a directional system. The directional system can be configured so that the directional pattern is targeted to eliminate the feedback path. This means that the directional response has minimal directivity towards the feedback path.

[0047] The hearing aid device may further comprise a second frequency band redistribution unit configured to distribute N P,2 processing channels are distributed to multiple (N O,2 In this embodiment, the signal processing unit is configured to generate a second N output frequency band based on the second bundling and allocation scheme. I,2 Each of the input frequency bands determines a second set of filter coefficients. The first filter coefficient of the first set of filter coefficients and the second filter coefficient of the second set of filter coefficients include a real part and an imaginary part. The imaginary parts of the first and second filter coefficients are determined to minimize the possibility of feedback and to minimize the impact on the part of the acoustic output signal that does not include feedback. The acoustic output signal includes each corresponding first filter coefficient multiplied by the corresponding first N O,1 The output frequency bands are multiplied by the corresponding second filter coefficients and the corresponding second N O,2 The sum of the output frequency bands.

[0048] With two microphones, each microphone can be tied differently if the feedback path of each microphone is different.

[0049] In a binaural hearing aid system, one or more microphones in each hearing aid may have different or identical bundling schemes.

[0050] If the analysis filter bank is defined in the time domain, filter coefficients are used. Conversely, if the analysis filter bank is defined in the frequency domain, complex weights are used. Alternatively, the frequency resolution within a frequency band can be increased using multiple complex filter coefficients instead of a single complex weight.

[0051] Applying spatial filtering to the frequency band being processed enables feedback reduction. To this end, it is advantageous to have the highest frequency resolution in a frequency region that includes at least one frequency band with a high likelihood of feedback. In a frequency region that includes a frequency band with a high likelihood of feedback, if the frequency band is narrow, spatial filtering of the corresponding frequency band is more effective in canceling feedback.

[0052] In a preferred embodiment, the feedback likelihood is determined by a feedback detection unit, which is either included in the hearing aid device or included by an external device. In the case where the feedback detection unit is included in the hearing aid device, it is possible to dynamically update the bundling and allocation scheme according to the changing feedback situation. If the feedback detection unit is not included in the hearing aid device and is configured as a non-feedback detection unit, a static bundling and allocation scheme may be installed.

[0053] In a preferred embodiment, the feedback detection unit is configured to determine the likelihood of feedback between the output of a loudspeaker forming a first feedback path and the input of the first microphone, and between the output of a loudspeaker forming a second feedback path and the input of the second microphone. If the hearing aid device includes two microphones, each microphone may be subject to feedback independently of the other. The first and second microphones receive first and second acoustic signals, which are converted into first and second electrical audio signals, respectively. The first and second analog-to-digital converters convert the first and second audio signals into first and second time domain input signals, respectively. Thus, the first and second input units convert the first and second time domain input signals into a plurality of first and second frequency bands, respectively. In order to dynamically determine whether at least one of the first and second input frequency bands includes a high likelihood of feedback, the first and second feedback paths can be determined. The memory unit stores data indicating which of the first and second input frequency bands are subject to a likelihood of feedback above a predetermined threshold. Subsequently, the first and second frequency band bundling and allocation units bundle the first and second input frequencies according to the first and second bundling and allocation schemes.

[0054] Optionally, the feedback detection unit may be configured to dynamically determine the first N I,1 At least one of the input frequency bands and / or the second N I,2 A possibility of feedback occurring in at least one of the N input frequency bands, and wherein the first frequency band bundling and allocation unit and / or the second frequency band bundling and allocation unit are configured to dynamically control the first N I,1 input frequency bands and / or N I,2 Bundling and allocation of a second input frequency band.

[0055] If the feedback situation changes over time, the changing frequency bands may include high feedback potential. The bundling and allocation scheme can be dynamically adjusted to these changes. Thus, the bundling of the first and second frequency bands can be dynamically controlled by the first and second frequency band bundling and allocation units, respectively.

[0056] The feedback detection unit may be further configured to perform adaptive feedback cancellation based on the acoustic signal detected by the first microphone and / or the second microphone to cancel the acoustic feedback.

[0057] Already at the feedback detection unit level, feedback cancellation can be performed using adaptive feedback cancellation.

[0058] In a preferred embodiment, the feedback detection unit is configured to adaptively track the feedback path over time based on a linear time-invariant filter, which is adapted to estimate the first and / or second feedback path, wherein the first and / or second filter coefficients are updated over time.

[0059] If feedback path changes can be tracked over time, the bundling and allocation scheme stored in the memory unit can be dynamically updated. Consequently, the performance of the hearing aid device can be improved for continuously changing listening situations. At the same time, frequency bands that do not contain a high likelihood of feedback can be bundled. Consequently, a smaller number of frequency bands are actually processed, resulting in a beneficial reduction in the required computational effort. This can also lead to reduced power consumption during use of the hearing aid device.

[0060] In a preferred embodiment, the frequency band bundling and allocation unit is configured to dynamically adjust the number N of first processing channels during normal use of the hearing aid device. P,1 and / or the number N of second processing channels P,2 .

[0061] Dynamically adjusting the number of first and second processing channels during normal use of the hearing aid device results in an improved listening experience because the likelihood of feedback occurring in at least one of the first and second frequency bands is continuously tracked and reduced by applying filters to the corresponding frequency band. Furthermore, due to the bundling of frequency bands with only a low likelihood of feedback, computing power is reduced, resulting in the advantage that the hearing aid device can be used for a longer period of time before batteries must be replaced.

[0062] The first and / or second frequency band bundling and allocation unit may be configured to allocate the first and / or second input frequency bands to corresponding first and / or second processing channels, respectively, according to the hearing impairment of the user.

[0063] In a preferred embodiment, the signal processing unit is further configured to process speech intelligibility information, and wherein the signal processing unit is further configured to prioritize processing of the first and second frequency bands for eliminating noise and improving speech intelligibility or for eliminating feedback in frequency bands where only a small speech intelligibility improvement is expected.

[0064] In a preferred embodiment, the signal processing unit is further configured to prioritize processing of the plurality of frequency bands based on the measured first and / or second feedback paths and the speech intelligibility index.

[0065] If there is a frequency region with a high probability of feedback occurring and if this frequency region is expected to benefit only slightly from noise reduction, directional processing can be applied that aims to eliminate the feedback path. In frequency regions with a small probability of feedback and that benefit from noise reduction, directional processing can be applied that aims to improve speech intelligibility. Generally, low (usually below 1000 Hz) and intermediate frequency regions contribute mostly to speech intelligibility, so that in these frequency regions, speech intelligibility can be improved by noise reduction. In addition, low and intermediate frequency regions usually include lower or smaller feedback possibilities. In contrast, higher frequency regions usually contribute less to overall speech intelligibility. Therefore, for higher frequency regions, it is advantageous to prioritize directional processing in order to eliminate feedback paths.

[0066] In a preferred embodiment, the first or second or both frequency band bundling and allocation units are configured to bundle adjacent input frequency bands for a necessary number of processing channels and allocate the corresponding frequency bands to be processed. If the frequency bands to be processed are processed in a necessary number of processing channels, computing power can be reduced and energy can be saved. The term "necessary number of processing channels" refers to a situation in which the bundling of input frequency bands is optimized towards efficient feedback cancellation and no more frequency bands than necessary for efficient feedback cancellation are bundled. For example, if frequency bands are bundled, although the feedback possibility of the corresponding frequency bands is small, the bundling is unnecessary. This situation is optimized according to the term "necessary new processing channels".

[0067] The hearing aid device may be a hearing instrument, a hearing aid, a bone conduction hearing aid, a headset, a headset, an ear protection device, an active ear protection system, a hands-free telephone system, a mobile phone, a teleconferencing system, a public address system, a karaoke system, a classroom amplification system, or a combination thereof.

[0068] The object of the present invention is also achieved by a hearing aid device system comprising two or more hearing aid devices according to at least one of the previous embodiments, wherein the hearing aid devices are adapted to exchange information about bundling of input frequency bands, preferably via a wireless communication link.

[0069] In a preferred embodiment, the hearing aid device system is configurable such that the same bundling scheme is applied to both hearing aid devices of a binaural system by exchanging synchronization control signals between the two hearing aid devices.

[0070] According to another aspect of the present invention, the above-mentioned object is achieved by a method of processing an input audio signal, comprising

[0071] - receiving a first acoustic signal and converting the first acoustic signal into a first electrical audio signal;

[0072] - converting the first electrical audio signal into a first time domain input signal;

[0073] -Convert the first time domain input signal into multiple (N I,1 ) first input frequency bands, wherein the number of the first input frequency bands N I,1 determined by a first analysis filter bank;

[0074] - Bundle adjacent first input frequency bands and distribute the first frequency bands to be processed to multiple (N P,1 ) first processing channel;

[0075] -Store the first N I,1 data on which of the input frequency bands are subject to a likelihood of feedback above a predetermined threshold;

[0076] - Generate a first bundling and allocation scheme that determines N I,1 The first band to be processed is the first N P,1 The allocation of processing channels, wherein the first bundling and allocation scheme depends on N I,1 the likelihood of feedback occurring in at least one of the input frequency bands;

[0077] -In N P,1 The first frequency band to be processed is processed in the first processing channels, wherein the number of the first processing channels is N. P,1 Less than the number N of the first input frequency bands I,1 ;

[0078] -Based on the first bundling and allocation scheme for N I,1 determining a first filter coefficient for each of a plurality of input frequency bands;

[0079] -N P,1 processing channels are distributed to multiple (N O,1 ) a first output frequency band; and

[0080] - transmitting an acoustic output signal into an ear of the user, wherein the acoustic output signal comprises each of the first filter coefficients multiplied by N O,1 The sum of the corresponding output frequency bands in the output frequency bands.

[0081] The summation can be replaced by a linear combination.

[0082] In a preferred embodiment of the above-mentioned aspect, the method for processing an input audio signal further comprises:

[0083] - receiving a second acoustic signal and converting the second acoustic signal into a second electrical audio signal;

[0084] - converting the second electrical audio signal into a second time domain input signal;

[0085] -Convert the second time domain input signal into multiple (N I,2 ) second input frequency bands, wherein the number of the second input frequency bands N I,2 determined by a second analysis filter bank;

[0086] - Bundle adjacent second input frequency bands and distribute the second frequency bands to be processed to a plurality of (N P,2 ) second processing channel;

[0087] -Store the second N I,2 data on which of the input frequency bands are subject to a likelihood of feedback above a predetermined threshold;

[0088] - Generate a second bundling and allocation scheme that determines N I,2 The input frequency bands are bundled and the second frequency band to be processed is the second N P,2 The second bundling and allocation scheme depends on N I,2 the likelihood of feedback occurring in at least one of the input frequency bands;

[0089] -In N P,2 The second frequency band to be processed is processed in a second processing channel, wherein the number of the second processing channels is N. P,2 Less than the number N of the second input frequency bands I,2 ;

[0090] -Based on the second bundling and allocation scheme for N I,2 determining a second filter coefficient for each of a plurality of input frequency bands;

[0091] -N P,2 processing channels are distributed to multiple (N O,2 ) a second output frequency band; and

[0092] - transmitting an acoustic output signal into an ear of a user, wherein the acoustic output signal comprises each of the first filter coefficients multiplied by a first N O,1 The corresponding output band in the output bands is multiplied by each of the second filter coefficients by the second N O,2 The sum of the corresponding output frequency bands in the output frequency bands.

[0093] The number of the second processing channels N P,2 The number of channels N that can be processed with the first P,1 Same.

[0094] The feedback probability may depend on the measured feedback path to each microphone, since it is desirable that the same bundling scheme be applied to each microphone. Otherwise, combining the two microphone signals becomes difficult.

[0095] In a preferred embodiment, a data processing system comprises a processor and a program code adapted to cause the processor to perform the steps of the method of at least one of the two above-mentioned aspects.

[0096] Cochlear implants may include:

[0097] - at least one input transducer for capturing incoming sound and for generating an electrical audio signal in a frequency band representative of the incoming sound;

[0098] - a sound processor configured to analyze and process electrical audio signals;

[0099] - a transmitter for sending the processed electrical audio signal;

[0100] - a receiver / stimulator that receives the processed electrical audio signal from the transmitter and converts the processed electrical audio signal into electrical pulses;

[0101] - an electrode array adapted to be implanted in the cochlea, comprising a plurality of electrodes for stimulating the cochlear nerve with said electrical pulses;

[0102] - a control unit configured to control the distribution of said electrical pulses to a plurality of said electrodes.

[0103] In the cochlear implant as described above, the distribution of the electrical pulses to the plurality of electrodes is performed by applying one of a plurality of different encoding schemes, wherein the applied encoding scheme is selected according to characteristics of the incoming sound.

[0104] Similarly, for cochlear implants, there may be stimulation situations where it is known that some frequency regions are not being used. An example is a telephone conversation, where the signal is band-limited, up to approximately 3500 Hz. Given this information, the available electrodes can be coded according to the specific listening situation. Using the example of a telephone conversation, the telephone signal can be distributed to multiple electrodes in a different manner than in other listening situations.

[0105] For example, in situations where not all frequencies need to be stimulated, it may be beneficial to use all available electrodes or to increase the stimulation rate. However, to adapt to different listening situations, different encoding schemes may be applied. For listening to music, it is also reasonable to apply a stimulation-specific encoding scheme.

[0106] In a cochlear implant, the sound processor may optionally be configured to analyze characteristics of incoming sound.

[0107] In a preferred embodiment of the cochlear implant, the control unit is configured to distribute the electrical pulses to the plurality of electrodes according to a coding scheme for telephone conversations and / or according to a coding scheme for listening to music and / or according to another coding scheme.

[0108] In a preferred embodiment of a cochlear implant, the encoding scheme for listening to music is configured so that the high-frequency band transmits cadence and the low-frequency band resolves tonal information. Typically, currently used encoding schemes are optimized for understanding speech. This requires a large amount of information to be encoded in the envelope. However, it is conceivable to encode music information differently, for example by using a high-frequency band to transmit cadence rather than spreading it across all frequency bands and using a low-frequency band to resolve tonal information.

[0109] The sound processor in the cochlear implant may optionally be configured to analyze the electrical audio signal of frequency bands representing incoming sound for information content and process only the frequency bands containing meaningful information so that a smaller number of electrodes than the total number of available electrodes are used to stimulate the cochlear nerve.

[0110] In a preferred embodiment of the cochlear implant, the audio processing device is configured to activate an energy-saving mode, in which the incoming sound is analyzed by the sound processor and only frequency bands of the incoming sound containing meaningful information are transmitted to the electrodes. In order to reduce the power consumption of the cochlear implant, some channels of the cochlear implant can be switched off depending on the input channel. If the acoustic input signal contains reduced or only contains less information above, for example, 3 kHz, the processing above 3 kHz can be switched off to save energy. Thus, a smaller number of electrodes can be used to stimulate the cochlear nerve. Alternatively, if the battery of the cochlear implant becomes low, a special energy-saving mode can be activated, in which the acoustic input signal is analyzed and only frequency bands containing a certain information content (i.e., the modulated signal) are transmitted to the electrodes.

[0111] In a preferred embodiment of the cochlear implant, the power-saving mode is configured to preferably use 1-2 broadband frequencies, which are directed to preferably 1-2 electrodes to transmit modulation for sound awareness in the event that the incoming sound is above a predetermined amplitude threshold. The described scenario refers to an extreme power-saving mode, in which only 1-2 broadband frequencies are used and mapped to 1-2 electrodes to transmit modulation for sound awareness, and only when the received acoustic input signal is above a predetermined threshold level.

[0112] The cochlear implant entering a power saving mode may be dependent on user interaction or reaction to incoming sound from one or more microphones, such as head movement or responses captured by the microphones.

[0113] Optionally, the control unit can be configured to control the distribution of electrical pulses to the plurality of electrodes so that electrical pulses are delivered to at least every second electrode to reduce channel interaction. By stimulating only every second electrode, channel interaction can be reduced. Therefore, in this stimulation mode, the user needs to adapt to a specific frequency distribution pattern that differs from a typical program.

[0114] In a preferred embodiment of the cochlear implant, at least one wall channel is provided to reduce channel interaction, wherein a wall channel is a channel in which no signal is present and adjacent to the edge of a channel in which a signal is present. To provide an increased, band-limited auditory nerve response, a so-called wall channel can be introduced, which can be adjacent to the edge of the frequency band in which the corresponding signal is present. For example, when a user is in the middle of a telephone conversation, the wall channel can be the next frequency band above 3.5 kHz. The idea behind this is to prevent excitation from propagating to high-frequency regions, which, lacking their own stimulation, might be more responsive to stimulation from lower-frequency electrodes. Essentially, high-frequency auditory nerve fibers can be found encoding highly degraded versions of the edge frequency bands. This can be confusing or irritating to the user.

[0115] In a preferred embodiment of the cochlear implant, the wall channel stimulation within the wall channel is a low-level stimulation, preferably a subthreshold pulse or a suprathreshold pulse. As a result of the wall channel being a low-level pulse, a response adjacent to the passband is generated, the level of which is low enough to have little or no perceptual relevance, and the corresponding neurons are occupied so that they do not respond much to the propagation of the stimulation from the lower frequency electrode.

[0116] Two or more cochlear implants according to at least one of the above-mentioned cochlear implant embodiments may also be included in a cochlear implant system, wherein these cochlear implants are adapted to exchange information about the applied coding scheme. Preferably, the exchange of information is provided via a wireless communication link.

[0117] In a preferred embodiment of the cochlear implant system, the cochlear implant system can be configured such that the same encoding scheme is applied to both cochlear implants of a binaural system by exchanging synchronization control signals between the two cochlear implants. BRIEF DESCRIPTION OF THE DRAWINGS

[0118] Various aspects of the present invention will be best understood from the following detailed description in conjunction with the accompanying drawings. For clarity, the drawings are schematic and simplified, showing only the details necessary for understanding the present invention and omitting other details. Throughout the specification, the same reference numerals are used for identical or corresponding parts. The various features of each aspect may be combined with any or all features of the other aspects. These and other aspects, features, and / or technical effects will be apparent from and elucidated in conjunction with the following figures, in which:

[0119] Figure 1 A schematic diagram of a hearing aid device is shown.

[0120] Figure 2 The processing steps of an acoustic signal received by a microphone are schematically shown.

[0121] Figure 3The steps of processing the acoustic signal received by two microphones are schematically shown.

[0122] Figure 4 The feedback path and directional pattern of a behind-the-ear (BTE) hearing aid device are shown.

[0123] Figure 5 The basic principle of an in-the-ear (ITE) microphone is shown.

[0124] Figure 6 Frequency bundling according to the prior art is exemplarily shown.

[0125] Figure 7 Frequency bundling according to the likelihood of feedback occurring in the corresponding frequency band is exemplarily shown.

[0126] Figure 8 The priority order of the frequency bands to be processed or the processing for eliminating noise and improving speech intelligibility or for eliminating feedback is shown by way of example.

[0127] Figure 9 A schematic diagram of a cochlear implant is shown.

[0128] Figure 10 The bundling of two matrices is mentioned.

[0129] Figure 11 It shows how the feedback path depends on the position of the loudspeaker in the user's ear canal.

[0130] Figure 12 It shows how an input signal with limited bandwidth, such as a telephone signal, can be distributed into a frequency band covering a wider frequency range. DETAILED DESCRIPTION

[0131] The detailed description presented below, in conjunction with the accompanying drawings, serves as a description of various configurations. The detailed description includes specific details designed to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be implemented without these specific details. Several aspects of hearing device systems and methods are described using various blocks, functional units, modules, components, circuits, steps, processes, algorithms, and the like (collectively, "elements"). Depending on the specific application, design constraints, or other reasons, these elements may be implemented using electronic hardware, computer programs, or any combination thereof.

[0132] A hearing device may be a hearing assistive device adapted to improve or enhance a user's hearing ability by receiving acoustic signals from the user's surroundings, generating corresponding audio signals, possibly modifying the audio signals, and providing the possibly modified audio signals as audible signals to at least one of the user's ears. A "hearing device" may also refer to a device, such as earphones or headphones, adapted to electronically receive audio signals, possibly modify the audio signals, and provide the possibly modified audio signals as audible signals to at least one of the user's ears. These audible signals may be provided in the form of acoustic signals radiated into the user's outer ear, acoustic signals transmitted as mechanical vibrations through the bony structure of the user's head and / or through the user's middle ear portion to the user's inner ear, or electrical signals transmitted directly or indirectly to the user's cochlear nerve and / or auditory cortex.

[0133] The hearing device is adapted to be worn in any known manner. This may include i) arranging the hearing device unit behind the ear with a tube for guiding airborne acoustic signals, or with a receiver / speaker arranged close to or in the ear, such as in a behind-the-ear hearing aid or a receiver-in-the-ear hearing aid, and / or ii) arranging the hearing device completely or partially in the pinna and / or ear canal of the user, such as in an in-the-ear hearing aid or an in-the-canal / completely in-the-canal hearing aid, or iii) arranging the hearing device unit attached to a fixture implanted in the skull, such as in a bone-anchored hearing aid or a cochlear implant, or iv) arranging the hearing device unit as a completely or partially implanted unit, such as in a bone-anchored hearing aid or a cochlear implant.

[0134] A hearing device may be part of a "hearing system," which refers to a system comprising one or two hearing devices as disclosed herein, and a "binaural hearing system" refers to a system comprising two hearing devices, wherein the devices are adapted to provide audio signals to both ears of a user in a coordinated manner. A hearing system or binaural hearing system may also include an auxiliary device that communicates with at least one hearing device, the auxiliary device influencing the operation of the hearing device and / or benefiting from the operation of the hearing device. A wired or wireless communication link is established between the at least one hearing device and the auxiliary device, enabling the exchange of information (e.g., control and status signals, and possibly audio signals) between the at least one hearing device and the auxiliary device. These auxiliary devices may include at least one of a remote control, a remote microphone, an audio gateway device, a mobile phone, a public address system, a car audio system, or a music player, or a combination thereof. The audio gateway is adapted to receive a plurality of audio signals, such as from an entertainment device such as a television or music player, a telephone device such as a mobile phone, or a computer or PC. The audio gateway is further adapted to select and / or combine an appropriate one of the received audio signals (or combination of signals) for transmission to the at least one hearing device. The remote control is adapted to control the functions and operation of the at least one hearing device. The functionality of the remote control may be implemented in a smartphone or other electronic device, which may run an application for controlling the functionality of the at least one hearing device.

[0135] Generally speaking, a hearing device includes i) an input portion, such as a microphone, for receiving acoustic signals from the user's surroundings and providing a corresponding input audio signal, and / or ii) a receiving unit for electronically receiving the input audio signal. The hearing device also includes a signal processing unit for processing the input audio signal and an output unit for providing an audible signal to the user based on the processed audio signal.

[0136] The input part may include multiple input microphones, for example for providing direction-dependent audio signal processing. Such a directional microphone system is suitable for enhancing a target acoustic source from a large number of acoustic sources in the user's environment. In one aspect, the directional system is suitable for detecting (for example adaptively detecting) from which direction a particular part of the microphone signal originates. This can be achieved by using conventionally known methods. The signal processing unit may include an amplifier, which is suitable for applying a frequency-dependent gain to the input audio signal. The signal processing unit may also be suitable for providing other related functions such as compression, noise reduction, etc. The output unit may include an output transducer such as a speaker / receiver for providing air-borne acoustic signals transcutaneously or percutaneously to the skull, or a vibrator for providing structure-borne or liquid-borne acoustic signals. In some hearing devices, the output unit may include one or more output electrodes such as in a cochlear implant for providing electrical signals.

[0137] It should be understood that throughout this specification, references to "one embodiment," "an embodiment," "an aspect," or features that "may" include, mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of the present invention. Furthermore, the particular features, structures, or characteristics may be appropriately combined in one or more embodiments of the present invention. The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects.

[0138] The claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein, unless specifically stated otherwise, singular references to elements are not intended to mean "one and only one" but rather "one or more." Unless specifically stated otherwise, the term "some" means one or more.

[0139] Accordingly, the scope of the present invention should be judged in light of the following claims.

[0140] Figure 1 1 shows an outline of a hearing aid device comprising a first microphone 10 configured to receive a first acoustic signal 1 and a second microphone 110 configured to receive a second acoustic signal 101. Figure 1 In an alternative embodiment not shown, the first and second microphones are located behind the user's ears as part of a behind-the-ear (BTE) hearing aid device. Figure 1 In another embodiment not shown, the first and second microphones are located in the ear canal of a user as part of an in-the-ear (ITE) hearing aid device. The first microphone 10 and the second microphone 110 convert the first acoustic signal 1 and the second acoustic signal 101 into a first electrical audio input signal 11 and a second electrical audio input signal 111, respectively.

[0141] The hearing aid device further includes a first analog-to-digital converter 20 for converting the first electrical audio input signal 11 into a first time domain input signal 21 and a second analog-to-digital converter 120 for converting the second electrical audio input signal 111 into a second time domain input signal 121. The first time domain signal 21 and the second time domain signal 121 are then transmitted to the digital signal processing unit 90A. The digital signal processing unit 90A includes a first input unit 30 and a second input unit 130. The first input unit 30 is configured to convert the first time domain input signal 21 into an N I,1 The number N of first input frequency bands 31 is thus I,1 is determined by the first analysis filter bank included in the first input unit 30. The second input unit 130 is configured to convert the second time domain input signal 121 into NI,2 The number N of second input frequency bands 131 is thus I,2 Determined by the second analysis filter bank included in the second input unit 130.

[0142] The hearing aid device further comprises first and second frequency band bundling and allocating units 40, 140. The first frequency band bundling and allocating unit 40 is configured to bundle adjacent first input frequency bands 31 and allocate the first frequency bands 41 to be processed to N P,1 The second frequency band bundling and allocation unit 140 is configured to bundle adjacent second input frequency bands 131 and allocate the second frequency bands 141 to be processed to N P,2 A second processing channel 151.

[0143] The bundling of the first input frequency band 31 and the second input frequency band 131 may be based on a first bundling scheme and a second bundling scheme, which are generated based on data stored in the memory 200. The data indicates the first N I,1 Which frequency bands in the input frequency band 31 and the second N I,2 Which of the input frequency bands 131 suffer from a feedback probability above a predetermined threshold. Figure 1 In a preferred embodiment not shown, the hearing aid device comprises two memory units which either store data indicating which frequency bands of the first input frequency bands are subject to a feedback probability above a predetermined threshold or store data indicating which frequency bands of the second input frequency bands are subject to a feedback probability above a predetermined threshold.

[0144] The first frequency band 41 to be processed and the second frequency band 141 to be processed are transmitted to the signal processing unit 50. The signal processing unit 50 is configured to P,1 The first frequency band 41 to be processed is processed in the first processing channel 51 and the N P,2 The second frequency band 141 to be processed is processed in the second processing channels 151. Here, the number N of the first processing channels 51 is preferably P,1 Less than the number N of the first input frequency bands 31 I,1 , and the number N of the second processing channels 151 P,2 Less than the number N of the second input frequency bands 131 I,2 The number of first and second processing channels N P,1 ,N P,2 The processing of the input frequency bands in a smaller number of processing channels may result in a reduction in computing power. This reduction in computing power may result in a reduction in power consumption of the hearing aid device, or the limited number of NP frequency bands may be used in the most efficient way.

[0145] The hearing aid device 100 further comprises a first frequency band redistribution unit 60 and a second frequency band redistribution unit 160. The first frequency band redistribution unit 60 is configured to P,1 The processing channels 51 are redistributed to N O,1 The first output frequency bands 61 and the second frequency band redistribution unit 160 are configured to P,2 The processing channels 151 are redistributed to N O,2 The number of second output frequency bands 161 is thus N. O,1 Can be greater than the number N of the first processing channels 51 P,1 , and the number N of the second output frequency bands 161 O,2 Can be greater than the number N of the second processing channels 151 P,2 The number of first and second output frequency bands N O,1 ,N O,2 Can be equal or different.

[0146] The first output frequency band 61 and the second output frequency band 161 are passed to a signal combining unit 90B, wherein the first and second frequency bands are combined into a digital audio output signal 91 (in the time domain) and passed to the digital-to-analog converter 70 .

[0147] In an embodiment, the signal combining unit 90B comprises a beamforming filter unit and / or a synthesis filter bank for providing a resulting spatially filtered signal by applying (possibly) complex (frequency-dependent) beamformer weights to the respective first and second electrical audio input signals. The beamforming filter unit may, for example, be configured to provide a beamformer that is least sensitive in the direction of a feedback origin (loudspeaker) in a frequency region where feedback is likely to occur (in which frequency region a higher frequency resolution is used according to the invention) and to (e.g. adaptively) minimize (other) noise in other frequency regions.

[0148] Using the digital-to-analog converter 70, the digital audio output signal 91 is converted into an (analog) electrical audio output signal 71, which is transmitted to the speaker 80. The speaker 80 is configured to transmit an acoustic output signal 81 based on the electrical audio output signal 71 to the ear of the user of the hearing aid device 100. Figure 1 In a preferred embodiment not shown, the speaker is placed in the user's ear canal.

[0149] exist Figure 1 In a preferred embodiment not shown, units of the same type, such as first and second input units, are included in a single unit having the same functionality as two separate units. Figure 1 In a preferred embodiment not shown, a plurality of units having different functions such as an input unit and an analog-to-digital converter may be included in the same unit that performs the functions of the included respective units. Figure 1In an alternative embodiment not shown, only one microphone is included, so that Figure 1 Either the upper branch or the lower branch shown in is included in this alternative embodiment. Figure 1 The various branches of the alternative embodiment still include Figure 1 The functionality of the memory cell 200 is shown in FIG.

[0150] As described above, the memory unit is configured to store a value indicating the first N I,1 input band and the second N I,2 Data on which frequency bands of the input frequency bands are subject to a feedback probability above a predetermined threshold is stored. In addition, the feedback probability is stored in a first and a second bundling scheme, which can be a two-dimensional matrix indicating whether the first and / or second input frequency bands should be bundled. This enables the implementation of a bundling scheme that produces a larger frequency resolution in the frequency region including frequency bands with a high feedback probability than in the frequency region including frequency bands with a smaller probability of feedback occurring. If the frequency resolution in the frequency region is high, it is possible to reduce or offset the feedback in the corresponding frequency bands very efficiently. This is because the corresponding frequency bands can be selected and processed individually, and filters are applied exclusively to these corresponding frequency bands. In addition, frequency bands with a small probability of feedback occurring can be bundled, so that the computational effort and thus the power consumption of the hearing aid can be reduced.

[0151] The likelihood of feedback occurring in at least one of the first and / or second frequency bands may be determined by the feedback detection unit 250. The feedback detection unit 250 detects the likelihood of feedback, for example, by dynamically tracking changes in the feedback path 251. Figure 1 In the embodiment of the present invention, the feedback path between (only) the loudspeaker 80 and the second microphone 110 is estimated by the feedback detection unit 250. If a high probability of feedback occurring in at least one of the second input frequency bands 131 is detected, the corresponding information is transmitted (252) to the memory unit 200 and stored as an indication of the second N I,2 The data may be used to determine which of the input frequency bands are subject to a feedback probability above a predetermined threshold.

[0152] exist Figure 1 In an alternative embodiment (not shown), two feedback detection units may be included, each of which functions exclusively for one processing branch. If one or more feedback detection units are included in a hearing aid device, dynamic tracking of feedback path changes may be implemented so that the first and / or second bundling schemes can be updated during operation of the hearing aid device based on changing feedback conditions. The first feedback detection unit may be configured to track changes in a first feedback path between a first microphone and a loudspeaker, and the second feedback detection unit may be configured to track changes in a feedback path between a second microphone and a loudspeaker.

[0153] exist Figure 1In an alternative embodiment (not shown), the feedback detection unit is implemented as an external feedback detection unit. The hearing care professional can detect the frequency bands that include a high likelihood of feedback and store data indicating which input frequency bands experience a likelihood of feedback above a predetermined threshold on a memory unit included in the hearing aid device. Thus, the frequency band bundling scheme will be a static scheme.

[0154] The signal processing described above can also be implemented in hearing aid implants, such as cochlear implants. In this case, the processed signal is not converted into an acoustic output signal emitted by a speaker. Instead, the processed electrical audio signal can be converted into electrical pulses. An electrode array comprising multiple electrodes embedded in the user's cochlea can then be used to stimulate the cochlear nerve with these electrical pulses.

[0155] The following will explain Figure 2 and 3 The focus is on the different signal processing steps implemented in a hearing aid device according to a preferred embodiment of the present invention. Figure 2 Focusing on hearing aid devices that include a microphone, Figure 3 A hearing aid device comprising two microphones is described.

[0156] Figure 2 FIG1 shows the signal processing steps in a hearing aid device according to a preferred embodiment of the present invention. First, the microphone 10 receives the acoustic signal 1, which is converted into N I input frequency bands 31 (e.g. by an analysis filter bank, see e.g. Figure 1 30 in ). The input frequency band 31 can be bundled or partially bundled and then allocated to N P Processing channels 51 (e.g., by the frequency band bundling and allocation unit 40, such as Figure 1 N P The N processing channels 51 are processed in the signal processing unit 50. The processing in the signal processing unit 50 may include the processing of N channels based on, for example, a bundling and distribution scheme. I Each of the input frequency bands determines the filter coefficient or gain value (Wp) 53. After signal processing, N P processing channels are redistributed to N O This enables filtering of selected frequency bands that are subject to a high likelihood of feedback or applying different gain levels to selected frequency bands depending on the specific listening situation.

[0157] In the embodiment shown, the number of input frequency bands N I and the number of output frequency bands N O Likewise, as shown by arrow 35. Therefore, the initial frequency resolution is smaller in the number of processing channels N. PThe acoustic output signal (Wp1*No1+Wp2*No2+Wp3*No3+…) provided by the loudspeaker 80 comprises each filter coefficient 53 multiplied by N O The sum of the phase shifted output bands in the output bands 61 (as determined by Figure 2 No output frequency bands (contents) can be obtained from N I An input frequency band 31 is received (35).

[0158] The signal processing described above can also be implemented in hearing aid implants, such as cochlear implants. In this case, the processed signal is not converted into an acoustic output signal emitted by a speaker. Instead, the processed electrical audio signal can be converted into electrical pulses. An electrode array comprising multiple electrodes embedded in the user's cochlea can then be used to stimulate the cochlear nerve with these electrical pulses. In this case, signals of various frequency bands (Wp1*No1, Wp2*No2, Wp3*No3, etc.) can be presented to different electrodes of the electrode array.

[0159] Figure 3 FIG. 4 shows the signal processing steps in a hearing aid device according to a preferred embodiment of the present invention. Figure 2 In contrast, a first microphone 10 and a second microphone 110 are included and configured to receive a first acoustic signal 1 and a second acoustic signal 101, respectively. The first acoustic audio signal 1 is converted into N I,1 The first input frequency bands, and the second acoustic audio signal 101 is converted into N I,2 The first input frequency bands 31 can be bundled according to the first bundling scheme, and the second input frequency bands 131 can be bundled according to the second bundling scheme. Subsequently, the plurality of first frequency bands to be processed are allocated to N P,1 The first processing channels 51 and the second frequency bands to be processed are allocated to N P,2 151 processing channels.

[0160] N P,1 The first processing channels 51 and N P,2 The second processing channels 151 are processed in the signal processing unit 50. The processing in the signal processing unit 50 may include processing the N channels based on, for example, the likelihood of feedback in at least one of the first and second input frequency bands. I,1 Each of the first input frequency bands determines a set of first filter coefficients (Wp1) 54 and a pair of N I,2 Each of the second input frequency bands determines a set of second filter coefficients (Wp2) 55. After signal processing, N P,1 The first processing channel and N P,2 The second processing channels are redistributed to NO,1 The first output frequency band and N O,2 Second output frequency band. N O,1 The first output frequency band and N O,2 Each of the second output frequency bands may be multiplied by a respective filter coefficient determined by the signal processing unit 50. This enables suppression of feedback in frequency bands including a high feedback possibility.

[0161] The first filter coefficient of the first set of filter coefficients (Wp1) and the second filter coefficient of the second set of filter coefficients (Wp2) may include a real part and an imaginary part. The real part and the imaginary part of the first and second filter coefficients may be determined so as to minimize the possibility of feedback and to minimize the impact on the part of the acoustic output signal that does not include feedback. In addition, the acoustic output signal (W1p1*No11+W1p2*No12+W1p3*No13+…+W2p1*No21+W2p2*No22+W2p3*No23+…) includes each of the corresponding first filter coefficients multiplied by the corresponding first N O,1 The output frequency band is multiplied by each second filter coefficient by the corresponding second N O,2 The (contents of) the output frequency bands may be received (35A and 35B) from the first input frequency band 31 and the second input frequency band 131.

[0162] The filter coefficients may have different objectives depending on the amount of feedback in feedback path 251. In frequency bands with a high risk of feedback, the coefficients are adjusted to minimize feedback. In frequency bands with a low risk of feedback (e.g., based on feedback path measurements, such as at low frequencies), the coefficients may be adjusted to minimize external noise.

[0163] The signal processing described above can also be implemented in hearing aid implants, such as cochlear implants. In this case, the processed signal is not converted into an acoustic output signal emitted by a speaker. Instead, the processed electrical audio signal can be converted into electrical pulses. An electrode array comprising multiple electrodes embedded in the user's cochlea can then be used to stimulate the cochlear nerve with these electrical pulses (e.g., each electrical pulse represents the content of a different output frequency band).

[0164] Figure 4A behind-the-ear (BTE) hearing aid device with two microphones is shown. In the case of a hearing aid device with two microphones, the directional system can be adjusted to eliminate the estimated feedback path 251. The feedback path is related to the distance between the first or second microphone 10, 110 and the loudspeaker 80. For a given frequency band, the directivity pattern 260 can be improved to eliminate the estimated feedback path 251 while maintaining the preferred listening direction. The left-hand embodiment may represent a receiver-in-the-ear (RITE) hearing device, in which the loudspeaker (receiver) is located in the ear canal (see the gray-shaded box). The right-hand embodiment may represent a BTE hearing device, in which the loudspeaker (receiver) is located in the BTE portion, and sound is propagated to the ear canal via a tube between the BTE portion and the ear canal (see the bold line (tp, to the right of the arrow indicating feedback path 251). In the illustrated embodiment, the directional response has minimal directivity toward the feedback path 251. In frequency regions where feedback is likely to occur, higher frequency resolution is desirable. Therefore, the frequency band bundling provided by the bundling scheme implementation can be performed so that the frequency resolution in the frequency region with a high feedback possibility is high.

[0165] At least one microphone (10, 110) can be used as a reference microphone for estimating feedback (see, for example, Figure 1 ).

[0166] Figure 5 An in-the-ear (ITE) hearing device is shown, comprising a dual microphone solution for feedback cancellation. A hearing aid device comprising two microphones 10, 110 placed in the ear canal of a user (see Figure 5 The left side) is even better suited to eliminating feedback paths than Figure 4 The two microphones 10, 110 may be spaced approximately 7-8 mm apart. Here, a fixed or adaptive directional gain may be applied (see directional diagram 260, see Figure 5 The goal is to cancel out the frequencies at which feedback occurs.

[0167] Figure 6 Signal processing according to the prior art (see, for example, EP2503794A1) is schematically illustrated. A time-domain input signal is converted into a plurality of input frequency bands. The plurality of input frequency bands is determined by an analysis filter bank. In the example shown, the frequencies increase from bottom to top, so that at the bottom of the analysis filter bank, low frequencies are shown, and at the top, high frequencies are shown. In order to reduce the computational effort and thus save energy, some of the input frequency bands are combined into a smaller number of processing channels. After processing, the processed frequency bands are redistributed to the original number of input frequency bands. Gains, which may be complex (e.g., fixed), are calculated during processing and applied to the plurality of output frequency bands. Subsequently, these frequency bands are processed by a synthesis filter bank to obtain a modified time-domain signal.

[0168] The signal processing described above can also be implemented in hearing aid implants, such as cochlear implants. Frequency band bundling can then be used to distribute electrical pulses to multiple electrodes. This distribution of the electrical pulses can be performed, for example, by applying one of a number of different encoding schemes, which can be selected based on the characteristics of the incoming sound.

[0169] Figure 7 The signal processing according to a preferred embodiment of the present invention is schematically shown. The first and second acoustic signals received by the first and second microphones are converted into first and second (such as digitized) time domain input signals, respectively, and passed to the analysis filter bank. The frequency bands enclosed by the braces 300 represent frequency bands in areas with high feedback potential. As recognized by the inventors of the present application, in frequency regions where feedback potential is high, it is desirable to have high frequency resolution to efficiently cancel feedback. Therefore, frequency bands where feedback may occur are not bundled, and frequency bundling is performed towards improving the elimination of feedback. In frequency regions where feedback may occur, the directional system can be adjusted towards eliminating the feedback path. In those frequency regions, which are typically higher frequency regions, it is desirable to have high frequency resolution.

[0170] After processing in a smaller number of processing channels, the processed frequency bands are redistributed into a plurality of output frequency bands, which may be the same number as the initial number of input frequency bands. During processing, filter coefficients (e.g., corresponding frequency band-specific gain values) are determined and applied to each output frequency band. Subsequently, the frequency bands are processed by a synthesis filter bank to obtain a modified time-domain signal.

[0171] The signal processing described above can also be implemented in hearing aid implants, such as cochlear implants. Frequency band bundling can then be used to distribute electrical pulses to multiple electrodes. This distribution of the electrical pulses can be performed, for example, by applying one of a number of different encoding schemes, which can be selected based on the characteristics of the incoming sound.

[0172] Figure 8 A scheme for prioritizing processing of frequency bands toward noise cancellation and improved speech intelligibility or toward feedback cancellation is shown. First and second acoustic signals received by first and second microphones are converted into first and second (e.g., digitized) time-domain input signals, respectively, and passed to an analysis filter bank.

[0173] Generally, directional processing in different frequency bands can be prioritized for noise cancellation and speech intelligibility improvement, or for feedback cancellation in frequency regions where only a small improvement in speech intelligibility is achieved. Such prioritization can be based on measured feedback paths and speech intelligibility band importance indices. To minimize power consumption, the bundling of frequency bands can be optimized to maintain sufficient frequency resolution for the fewest processing channels necessary to adequately present the information contained in the signal.

[0174] At low and mid-range frequencies (indicated by curly brackets) 400, directional processing for noise reduction significantly improves speech intelligibility. Similarly, in the low-frequency region, typically below 1000 Hz, feedback is unlikely to occur. In the higher-frequency region (indicated by curly brackets) 440, which contributes only slightly to overall speech intelligibility, it is reasonable to prioritize directional processing from these frequency regions to eliminate feedback paths.

[0175] In a binaural hearing aid system, the bundling scheme can be the same for both the left and right hearing aids. Thus, the bundling scheme depends on feedback path measurements at both hearing aids. In another example, the bundling scheme can be different for the left and right hearing aids. In yet another example, the bundling scheme can be partially the same for the left and right hearing aids, for example, the bundling schemes are the same in one frequency range but different in another.

[0176] The prioritization scheme described above can also be implemented in hearing aid implants such as cochlear implants.The prioritization of frequency bands can then be used and applied to the distribution of electrical pulses to a plurality of electrodes.

[0177] Figure 9 A cochlear implant 1000 is shown comprising an external portion 1100 and an implant portion 1200. The external portion (1100, 1010) comprises at least one input transducer 1010 for capturing incoming sound 1011 and for generating an electrical audio signal 1012 representing a frequency band of the incoming sound 1011. A sound processor 1020 is configured to analyze and process the electrical audio signal 1012, and a transmitter 1030 transmits the processed electrical audio signal 1021 to a receiver / stimulator 1040, for example, via an inductive link 1031. The receiver / stimulator 1040 receives the processed electrical audio signal 1021 from the transmitter 1030 and converts the processed electrical audio signal 1021 into electrical pulses 1041. A control unit 1060 is configured to control the distribution 1061 of the electrical pulses 1041 to a plurality of electrodes 1055. The electrode array 1050 embedded (implanted) in the cochlea includes a plurality of electrodes 155 for stimulating the cochlea with the electrical pulses 1041. In the cochlear implant 1000, the electrical pulses 1041 are distributed to the plurality of electrodes 155 by applying one of a plurality of different encoding schemes, wherein the applied encoding scheme is selected according to the characteristics of the incoming sound 1011.

[0178] Figure 10An example of a bundling and allocation scheme is shown as a two-dimensional matrix comprising 1s and 0s, where 1s define, for example, frequency bands that are to be bundled and 0s define frequency bands that are not to be bundled. For example, the columns may define processing channels NP,1 and the rows may define input frequency bands NI and vice versa. Thus, the bundling and allocation scheme determines which input frequency bands are to be bundled and / or allocated based on the probability of feedback occurring in the corresponding input frequency bands. The two-dimensional matrix is ​​multiplied by a one-dimensional matrix comprising No output frequency bands. Each output frequency band is identical to the input frequency band Ni, i.e. No1 is equal to Ni1. The result shows a redistribution of Np processing channels to No output frequency bands. This enables filtering of selected frequency bands that are subject to a high probability of feedback or applying different gain levels to selected frequency bands depending on the specific listening situation.

[0179] Figure 11 Different positions of the loudspeaker 80 in the ear of a user of the hearing aid 100 (see the upper left (A) and upper right (B) outlines) and the effect on the feedback path 251 as a function of frequency (see the corresponding lower left and lower right graphs) are shown. It can be seen that when the loudspeaker 80 is placed further outward in the ear (case B on the right), the peak in the feedback path measured in dB has shifted upward (in frequency). In general, the feedback path changes depending on the position of the loudspeaker 80 in the ear of the user, whereby different frequency ranges with a high likelihood of feedback are to be expected. Therefore, preferably, frequency band bundling, such as first and / or second frequency band bundling, can be provided based on the measurement results of the feedback path 251 to determine whether a change has occurred in the feedback path 251.

[0180] Figure 12 This shows how an input signal with limited bandwidth (such as a telephone signal) can be distributed into a frequency band covering a wider frequency range. This can be used, for example, in cochlear implants, where more information can be transmitted to the brain if all electrodes are stimulated, rather than stimulating only the electrodes covering the frequency range of the input stimulation. The redistribution of a narrow-band input signal into a wider output frequency band can be interpreted as bandwidth expansion.

Claims

1. A cochlear implant, comprising: - at least one input transducer for capturing incoming sound and for generating an electrical audio signal in a frequency band representative of the incoming sound; - a sound processor configured to analyze and process electrical audio signals; - a transmitter for sending the processed electrical audio signal; - a receiver / stimulator that receives the processed electrical audio signal from the transmitter and converts the processed electrical audio signal into electrical pulses; - an electrode array adapted to be implanted in the cochlea, comprising a plurality of electrodes for stimulating the cochlear nerve with said electrical pulses; and - a control unit configured to control the distribution of said electrical pulses to a plurality of said electrodes; wherein the control unit is configured to distribute the electrical pulses to the plurality of electrodes by applying one of a plurality of different coding schemes, wherein the applied coding scheme is selected based on characteristics of the incoming sound, wherein the sound processor is configured to analyze the characteristics of the incoming sound, The control unit is configured to distribute the electrical pulses to the plurality of electrodes so as to cover a frequency range wider than that of the electrical audio signal. 2 . The cochlear implant of claim 1 , wherein the control unit is configured to distribute the electrical pulses to the plurality of electrodes according to a coding scheme used for telephone conversations.

3. The cochlear implant according to claim 1, wherein: The distribution of the electrical pulses to the plurality of electrodes is performed according to a specific listening situation.

4. The cochlear implant of claim 1, configured to increase the stimulation rate when not all frequencies need to be stimulated.

5. The cochlear implant according to claim 1, wherein: The energy-saving mode of the cochlear implant is configured to use 1 or 2 wide frequency bands that are passed to 1 or 2 electrodes to transmit modulation for sound awareness if the incoming sound is above a predetermined amplitude threshold.

6. The cochlear implant according to claim 1, wherein: The sound processor in the cochlear implant is configured to analyze the electrical audio signal of frequency bands representing incoming sound for information content and to process only the frequency bands containing meaningful information so that a smaller number of electrodes than the total number of available electrodes are used to stimulate the cochlear nerve.

7. The cochlear implant of claim 1, configured to activate a power saving mode, wherein incoming sound is analyzed by the sound processor and only frequency bands of the incoming sound containing meaningful information are transmitted to the electrodes.

8. The cochlear implant according to claim 1, wherein: Some channels of the cochlear implant are turned off depending on the input channel.

9. The cochlear implant according to claim 1, wherein: A special energy-saving mode is activated, in which the acoustic input signal is analyzed and only frequency bands containing a certain information content are passed to the electrodes.

10. The cochlear implant according to claim 1, wherein: The control unit is configured to control the distribution of the electrical pulses to the plurality of electrodes such that the electrical pulses are delivered to alternating electrodes to reduce channel interaction.

11. The cochlear implant according to claim 1, wherein: At least one wall channel is provided to reduce channel interaction, wherein a wall channel is a channel in which no signal exists and is adjacent to an edge of a channel in which a signal exists.

12. The cochlear implant according to claim 11, wherein: While the user is in a telephone conversation, the wall channel is provided at the next frequency channel above 3.5 kHz.

13. The cochlear implant of claim 1, comprising an external portion and an implant portion.

14. The cochlear implant according to claim 1, wherein: Different encoding schemes among the plurality of different encoding schemes use different frequency regions to adapt to different listening situations, and the cochlear implant is configured to select a encoding scheme from the plurality of different encoding schemes according to an applicable listening situation among the different listening situations.

15. The cochlear implant according to claim 14, wherein: The cochlear implant adapts the bundling of frequency bands to different listening situations by selecting among a plurality of different encoding schemes.

16. The cochlear implant according to claim 14, wherein: The different listening situations include: telephone conversation and listening to music.

17. A cochlear implant system comprising two or more cochlear implants, each cochlear implant comprising: - at least one input transducer for capturing incoming sound and for generating an electrical audio signal in a frequency band representative of the incoming sound; - a sound processor configured to analyze and process electrical audio signals; - a transmitter for sending the processed electrical audio signal; - a receiver / stimulator that receives the processed electrical audio signal from the transmitter and converts the processed electrical audio signal into electrical pulses; - an electrode array adapted to be implanted in the cochlea, comprising a plurality of electrodes for stimulating the cochlear nerve with said electrical pulses; and - a control unit configured to control the distribution of said electrical pulses to a plurality of said electrodes; wherein the control unit is configured to distribute the electrical pulses to the plurality of electrodes by applying one of a plurality of different coding schemes, wherein the applied coding scheme is selected based on characteristics of the incoming sound, wherein the sound processor is configured to analyze the characteristics of the incoming sound, wherein the control unit is configured to distribute the electrical pulses to a plurality of the electrodes so as to cover a frequency range wider than that of the electrical audio signal, and Wherein the two or more cochlear implants are adapted to exchange information about the applied coding scheme.

18. The cochlear implant system according to claim 17, wherein: The exchange of information is provided via a wireless communication link.

19. The cochlear implant system according to claim 17, wherein: The control unit of each of the two or more cochlear implants is configured to distribute the electrical pulses to the plurality of electrodes according to a coding scheme for telephone conversations and / or according to a coding scheme for listening to music and / or according to another coding scheme.

Images