Hearing aid configured to select a reference microphone

Abstract

A hearing aid configured to select a reference microphone, the hearing aid comprising: at least two microphones providing respective at least two electrical input signals representing sound; a filter bank converting the at least two electrical input signals into signals as a function of time and frequency; a directional system connected to the at least two microphones configured to provide filtered signals from the at least two electrical input signals and fixed or adaptively updated beamformer weights; and a direction to a target sound source defined as a target direction; wherein for each frequency band one of the at least two microphones is selected as a reference microphone at a given point in time, thereby providing a reference input signal for each frequency band; wherein for a target sound incident on the hearing aid from the target direction at a given point in time, the reference microphone for a given frequency band is selected at the given point in time in dependence of directional data related to directional characteristics of the at least two microphones.

Description

Technical Field

[0001] This application relates to the field of hearing aids, and more particularly to hearing aids comprising multiple (e.g., ≥2) input transducers (e.g., microphones) and a directional system (beamformer) for providing (spatial) filtered (beamforming) signals based on signals from the input transducers (and predetermined or adaptively updated filter weights). Background Technology

[0002] Hearing instruments with directional noise reduction typically contain two or more microphones. The microphone positions vary between different dual-microphone instruments. Figure 1A , 1B As shown in the image. Figure 1A The typical position of the microphone in a behind-the-ear (BTE) hearing aid HD is shown. Figure 1B The image shows the typical location of the microphone in an in-the-ear (ITE) hearing device (HD). In two scenarios, the user wears the HD hearing device on the ear, such as behind the auricle, or in or within the ear canal. Summary of the Invention

[0003] hearing aids

[0004] In one aspect of this application, a hearing aid suitable for wear by a user in or in the ear, or partially or completely implanted in the head of a user's ear is provided. The hearing aid includes:

[0005] - At least two microphones that provide at least two electrical input signals corresponding to the sounds around the user wearing the hearing aid;

[0006] - A filter bank that converts at least two electrical input signals into signals that are functions of time and frequency, for example, represented by a complex-valued time-frequency unit;

[0007] - A directional system connected to at least two microphones, configured to provide a filtered signal based on at least two electrical input signals and fixed or adaptively updated beamformer weights; and

[0008] - Defined as the direction of at least one target sound source.

[0009] The hearing aid can be configured such that, for each frequency band, one of the at least two microphones is selected as the reference microphone at a given time point, thereby providing a reference input signal for each frequency band. The hearing aid can also be configured such that the reference microphones for at least two frequency bands are different.

[0010] This allows for the provision of hearing aids with improved beamforming.

[0011] The reference microphone can be selected offline, for example, when the target direction is fixed. The reference microphone can also be selected (predefined) before operation, but different reference microphones can be selected for different frequency bands. In other words, the reference microphone is pre-selected for a given frequency band but can vary across frequency bands.

[0012] The reference microphone for a given frequency band can be adaptively selected. The reference microphone for a given frequency band can also be adaptively selected based on logical criteria. These logical criteria can be predefined. The logical criteria can be updated according to the current acoustic environment. The logical criteria can also be selected from the user interface.

[0013] The reference microphone can be (and usually will be) a real (physical) microphone. In some cases, the (reference) signal from the reference microphone can be time-shifted to align with the cross-channel time delay difference from the direction of the target. That is, the reference microphone still has norm = 1, but the time shift can be applied to two microphones in a given channel to align the arrival time of the target signal.

[0014] The hearing aid may include memory or circuitry for establishing a communication link to a database, including directional data relating to the directional characteristics of at least two microphones. Logical criteria may include adaptive selection of a reference microphone for a given frequency band based on the directional data. The directional data may include a directivity index or a front-to-back ratio. The directional data may be stored in memory or a database, and for different target directions, may include frequency-varying values ​​of the directivity index or front-to-back ratio.

[0015] Logical criteria may include a comparison of the estimated relative transfer functions of at least two microphones. For a given frequency band k, the reference microphone may be selected as the one that picks up the most energy from the target direction. For a given frequency band k, the reference microphone may be selected as the microphone with the largest relative transfer function with respect to the target direction, for example, the largest value among the elements of the relative transfer function. In such a case, the reference microphone would be selected as the microphone that exhibits the largest relative transfer function with respect to the target direction of another microphone in a given frequency band.

[0016] In cases involving at least two microphones, including two or more microphones or three or more microphones, the reference microphone for a given frequency band k can be adaptively selected based on the maximum value of the directional data for each microphone. For example, the reference microphone for a given frequency band k can be selected as a microphone exhibiting the maximum directivity index (DI), maximum front-to-back ratio (FBR), maximum transfer function, etc., at a given time point (for a target sound source of interest to the user (incidentally on the hearing aid from a specific direction at the given time point)).

[0017] A reference microphone for a given frequency band k can be selected based on the maximum value of the directional data for each microphone (e.g., adaptively).

[0018] A reference microphone for a given frequency band k can be selected based on the maximum value of the target directivity of each microphone (e.g., adaptively). The term "target directivity" in this specification can be understood not only as directivity in a single direction, but also as directivity across a wider range of directions, such as having the highest front-to-back ratio.

[0019] A reference microphone for a given frequency band k can be selected based on the maximum directivity of each microphone for a given target direction (e.g., adaptively).

[0020] A reference microphone for a given frequency band k can be selected (e.g., adaptively) based on the maximum directivity of each microphone for a wider range of target directions. The reference microphone for a given frequency band k can be adaptively selected as the microphone with the highest front-to-back ratio in that given frequency band.

[0021] For a given frequency band k, the reference microphone can be (e.g., adaptively) selected as a microphone that exhibits the maximum directivity index (DI) or maximum front-to-back ratio (FBR) at a given time point (for the target sound source of the user’s current interest (which is incident on the hearing aid from a specific direction at the given time point)).

[0022] On one hand, this application provides a hearing aid suitable for a user to wear in or in the ear, or partially or completely implanted in the head of the user's ear. The hearing aid includes:

[0023] - At least two microphones that provide at least two electrical input signals corresponding to the sounds around the user wearing the hearing aid;

[0024] - A filter bank that converts at least two electrical input signals into signals that are functions of time and frequency, for example, represented by a complex-valued time-frequency unit;

[0025] - A directional system connected to at least two microphones, configured to provide a filtered signal based on at least two electrical input signals and fixed or adaptively updated beamformer weights; and

[0026] - Defined as the direction of the target sound source.

[0027] For each frequency band, one of the at least two microphones is selected as a reference microphone at a given time point, thereby providing a reference input signal for each frequency band. The reference microphone for a given frequency band may be selected as the microphone that exhibits the maximum directivity index or the maximum front-to-back ratio for a target sound incident on the hearing aid from the target direction at a given time point.

[0028] like Figure 3A , 3BAs shown in Figure 3C, for a given direction of arrival of sound relative to the hearing aid, the microphone with the highest directivity index in that direction varies across the frequency band. Therefore, it is advantageous to select a reference microphone with the highest directivity index in that given direction within a given frequency band.

[0029] Directional systems may include minimum variance distortionless response (MVDR) beamformers.

[0030] Depending on the selected reference microphone, the directional system may be implemented as or include an MVDR beamformer.

[0031] The processing of the MVDR beamformer depends on the steering vector d, which contains the acoustic transfer function from the target sound to each microphone relative to the reference microphone.

[0032] For an MVDR beamformer, the sound incident from the target direction will be undistorted compared to the target sound picked up by the reference microphone in a specific frequency band. In other words, the sound processed (i.e., the target signal) by the MVDR beamformer is undistorted compared to the sound from the selected reference microphone.

[0033] The target direction can be provided via a user interface. The hearing aid may include a user interface configured to allow the user to indicate the target direction, for example, see [link to relevant documentation]. Figure 5 .

[0034] Hearing aids can be configured to estimate the direction of a target. The processor in the hearing aid may include an algorithm for estimating the direction of attack (DOA) of a sound source (e.g., a target sound source) in the user's environment. The hearing aid may include a linear microphone array configured, once installed in operation, to align the microphones with the user's frontal / facing direction.

[0035] Hearing aids may include a speech activity detector for estimating whether, or with what probability, the input signal includes speech at a given time point. The speech activity detector may enable operation based on the noise covariance matrix (R0). v The filter weights w are adaptively estimated using the transfer function (d, when speech is not present) and the transfer function (d, when speech is detected).

[0036] Hearing aids may consist of or include air conduction hearing aids, bone conduction hearing aids, cochlear implant hearing aids, or combinations thereof.

[0037] Hearing aids may be adapted to provide frequency-varying gain and / or level-varying compression and / or frequency shifting (with or without frequency compression) from one or more frequency ranges to one or more other frequency ranges to compensate for a user's hearing loss. Hearing aids may include a signal processor for amplifying the input signal and providing a processed output signal.

[0038] Hearing aids may include an output unit for providing stimulation, perceived by the user as an acoustic signal, based on processed electrical signals. The output unit may include multiple electrodes of a cochlear implant (for CI-type hearing aids) or a vibrator of a bone conduction hearing aid. The output unit may include an output transducer. The output transducer may include a receiver (speaker) for providing the stimulation as an acoustic signal to the user (e.g., in acoustic (air conduction-based) hearing aids). The output transducer may also include a vibrator for providing the stimulation as mechanical vibrations of the skull to the user (e.g., in bone-attached or bone-anchored hearing aids).

[0039] Hearing aids may include an input unit for providing an electrical input signal representing sound. The input unit may include an input transducer, such as a microphone, for converting the input sound into an electrical input signal. The input unit may include a wireless receiver for receiving wireless signals that include or represent sound and providing an electrical input signal representing said sound. The wireless receiver may, for example, be configured to receive electromagnetic signals in the radio frequency range (3 kHz to 300 GHz). The wireless receiver may, for example, be configured to receive electromagnetic signals in the optical frequency range (e.g., infrared light 300 GHz to 430 THz or visible light such as 430 THz to 770 THz).

[0040] Hearing aids include directional microphone systems adapted to spatially filter sound from the environment, thereby enhancing a target sound source among multiple sound sources in the local environment of the hearing aid wearer. The directional system can be adapted to detect (e.g., adaptive detection) the direction from which a specific portion of the microphone signal originates. This can be achieved, for example, in a variety of different ways described in the prior art. In hearing aids, microphone array beamformers are commonly used to spatially attenuate background noise sources. Many beamformer variations can be found in the literature. Minimum variance distortionless response (MVDR) beamformers are widely used in microphone array signal processing. Ideally, an MVDR beamformer keeps the signal from the target direction (also known as the line of sight) unchanged while attenuating sound signals from other directions to the greatest extent possible. The generalized sidelobe canceller (GSC) structure is an equivalent representation of the MVDR beamformer, offering computational and digital representation advantages over a direct implementation of the original form.

[0041] Hearing aids may include antennas and transceiver circuitry, enabling wireless links to entertainment devices (such as televisions), communication devices (such as telephones), wireless microphones, or other hearing aids. Therefore, a hearing aid may be configured to wirelessly receive direct electrical input signals from another device. Similarly, a hearing aid may be configured to wirelessly transmit direct electrical output signals to another device. The direct electrical input or output signals may represent or include audio signals and / or control signals and / or information signals.

[0042] Preferably, the frequency used to establish a communication link between the hearing aid and another device is below 70 GHz, for example, in the range of 50 MHz to 70 GHz, or above 300 MHz, for example, in the ISM range above 300 MHz, for example, in the 900 MHz range, or in the 2.4 GHz range, or in the 5.8 GHz range, or in the 60 GHz range (ISM = Industrial, Scientific and Medical, such standardized ranges are defined, for example, by the International Telecommunication Union ITU). The wireless link may be based on standardized or proprietary technologies. The wireless link may be based on Bluetooth technology (such as Bluetooth Low Energy technology).

[0043] Hearing aids can be portable (i.e., configured to be wearable) devices or part of them, such as devices that include local power sources like batteries, such as rechargeable batteries.

[0044] Hearing aids may include a forward or signal path between an input unit (such as an input converter, for example a microphone or microphone system and / or a direct electrical input (such as a wireless receiver)) and an output unit such as an output converter. A signal processor may be located in this forward path. The signal processor may be adapted to provide frequency-varying gain according to the user's specific needs. Hearing aids may include an analysis path having functionalities for analyzing the input signal (such as determining level, modulation, signal type, acoustic feedback estimate, etc.). Some or all of the signal processing of the analysis path and / or signal path may be performed in the frequency domain. Some or all of the signal processing of the analysis path and / or signal path may be performed in the time domain.

[0045] Analog electrical signals representing sound signals can be converted into digital audio signals during analog-to-digital (AD) conversion, where the analog signal is sampled at a predetermined sampling frequency or sampling rate f. s Perform sampling, f s For example, in the range from 8kHz to 48kHz (to suit specific application needs) at discrete time points t n (or n) provides digital samples x n (or x[n]), each audio sample passes through a predetermined N b Bit represents the acoustic signal at t n The value of N at time b For example, in the range of 1 to 48 bits, such as 24 bits. Each audio sample therefore uses N. b Bit quantization (resulting in 2^n voltammetry of audio samples) Nb (Number of different possible values). The numerical sample x has 1 / f s The duration of the time, such as 50 μs, for f s =20kHz. Multiple audio samples can be arranged in time frames. A time frame can include 64 or 128 audio data samples. Other frame lengths can be used depending on the application.

[0046] Hearing aids may include analog-to-digital (AD) converters to digitize analog inputs (e.g., from an input converter such as a microphone) at a predetermined sampling rate such as 20 kHz. Hearing aids may also include digital-to-analog (DA) converters to convert digital signals into analog output signals, for example, for presentation to the user via an output converter.

[0047] Hearing aids, such as input units and / or antenna and transceiver circuitry, include a time-frequency (TF) conversion unit for providing a time-frequency representation of the input signal. The time-frequency representation may include an array or mapping of corresponding complex or real values ​​of the signal in question over a specific time and frequency range. The TF conversion unit may include a filter bank for filtering the (time-varying) input signal and providing multiple (time-varying) output signals, each output signal encompassing a distinctly different frequency range of the input signal. The TF conversion unit may include a Fourier transform unit for converting the time-varying input signal into a (time-varying) signal in the (time-frequency) domain. The hearing aid considers a frequency range starting from the minimum frequency f. min up to the maximum frequency f max The frequency range can include a portion of the typical human hearing range from 20Hz to 20kHz, such as a portion of the range from 20Hz to 12kHz. Typically, the sampling rate f... s Greater than or equal to the maximum frequency f max twice, that is, f s ≥2f max The signals from the forward and / or analytical pathways of the hearing aid can be divided into NI (e.g., uniformly wide) frequency bands, where NI is, for example, greater than 5, greater than 10, greater than 50, greater than 100, or greater than 500, and at least some of these bands are processed individually. The hearing aid may be adapted to process the signals from the forward and / or analytical pathways (NP≤NI) on NP different channels. The channels may have consistent or inconsistent widths (e.g., width increases with frequency), and may overlap or not overlap.

[0048] Hearing aids can be configured to operate in different modes, such as a normal mode and one or more specific modes, which may be user-selectable or automatically selectable. Operating modes can be optimized for specific acoustic conditions or environments. Operating modes may include low-power modes, where the hearing aid's functionality is reduced (e.g., for energy saving), such as disabling wireless communication and / or disabling specific features of the hearing aid.

[0049] Hearing aids may include multiple detectors configured to provide status signals relating to the hearing aid's current network environment (such as the current acoustic environment), and / or the current state of the user wearing the hearing aid, and / or the current state or operating mode of the hearing aid. Alternatively or additionally, one or more detectors may form part of an external device that communicates with the hearing aid (e.g., wirelessly). External devices may include, for example, another hearing aid, a remote control, an audio transmission device, a telephone (e.g., a smartphone), external sensors, etc.

[0050] One or more of a plurality of detectors can operate on a full-band signal (time domain). One or more of a plurality of detectors can operate on a band-split signal ((time-)frequency domain), for example, in a finite number of frequency bands.

[0051] Multiple detectors may include level detectors for estimating the current level of the signal in the forward path. Detectors may be configured to determine whether the current level of the signal in the forward path is above or below a given (L-) threshold. Level detectors operate on full-band signals (time domain). Level detectors operate on band-split signals ((time-)frequency domain).

[0052] Hearing aids may include a voice activity detector (VAD) for estimating whether (or with what probability) an input signal (at a specific point in time) includes a voice signal. In this specification, a voice signal may include speech signals from humans. It may also include other forms of vocalization produced by the human speech system (such as singing). The voice activity detector unit may be adapted to classify the user's current acoustic environment as a "voice" or "no-voice" environment. This has the advantage that time periods including electrophonic signals of human vocalizations (such as speech) in the user's environment can be identified and thus separated from time periods that include only (or primarily) other sound sources (such as artificially generated noise). The voice activity detector may be adapted to also detect the user's own voice as "voice." Alternatively, the voice activity detector may be adapted to exclude the user's own voice from the detection of "voice."

[0053] Hearing aids may include a self-voice detector for estimating whether (or with what probability) a particular input sound (such as speech) originates from the user of the hearing aid system. The microphone system of the hearing aid may be adapted to distinguish between the user's own voice and the voice of another person, and possibly between the user's own voice and non-voice sounds.

[0054] Multiple detectors may include motion detectors, such as accelerometers. Motion detectors may be configured to detect movements of a user's facial muscles and / or bones, such as those caused by speech or chewing (e.g., jaw movements), and provide detector signals indicating those movements.

[0055] The hearing aid may include a classification unit configured to classify the current situation based on input signals from (at least partially) a detector and possibly other inputs. In this specification, "current situation" may be defined by one or more of the following:

[0056] a) Physical environment (including the current electromagnetic environment, such as the presence of electromagnetic signals (including audio and / or control signals) that are planned or unplanned to be received by the hearing aid, or other properties of the current environment that are different from acoustics);

[0057] b) Current acoustic conditions (input level, feedback, etc.); and

[0058] c) The user's current mode or state (movement, temperature, cognitive load, etc.);

[0059] d) The current mode or state of the hearing aid and / or another device communicating with the hearing aid (selected program, time elapsed since the last user interaction, etc.).

[0060] The classification unit may be based on or include a neural network, such as a trained neural network.

[0061] Hearing aids may also include other suitable functions for the applications involved, such as compression, noise reduction, and feedback control.

[0062] Hearing aids may include hearing instruments, such as hearing instruments adapted to be placed in the user's ear or wholly or partially in the ear canal, such as headphones, headsets, ear protection devices, or combinations thereof. Hearing aid systems may include loudspeaker amplifiers (containing multiple input converters and multiple output converters, for example, for use in audio conferencing situations), and may include beamforming filter units, for example, providing multiple beamforming capabilities.

[0063] application

[0064] On the one hand, applications of the hearing aids described in detail in the "Detailed Description" section and as defined in the claims are provided. Applications can be provided in systems including audio distribution. Applications can be provided in systems including one or more hearing aids (such as hearing instruments), headphones, headsets, active ear protection systems, etc., such as hands-free telephone systems, teleconferencing systems (e.g., including loudspeaker amplifiers), broadcasting systems, karaoke systems, classroom amplification systems, etc.

[0065] method

[0066] On one hand, this application further provides a method for operating a hearing aid, the hearing aid being adapted for wear by a user in or in the user's ear, or partially or completely implanted in the head in the user's ear, the hearing aid comprising at least two microphones. The method includes:

[0067] - Provide at least two electrical input signals, each representing the sound around the user wearing the hearing aid, through at least two microphones;

[0068] - Convert at least two electrical input signals into signals that are functions of time and frequency, for example, represented by a complex-valued time-frequency unit;

[0069] - Provide a filtered signal based on at least two electrical input signals and fixed or adaptively updated beamformer weights; and

[0070] - Define at least one direction toward the target sound source as the target direction.

[0071] The method may further include, for each frequency band, selecting one of the at least two microphones as a reference microphone at a given time point, thereby providing a reference input signal for each frequency band. For a target sound incident on the hearing aid from a target direction at a given time point, the reference microphone for a given frequency band may be selected at the given time point based on directional data relating to the directional characteristics of the at least two microphones.

[0072] The method may also include making the reference microphones different for at least two frequency bands.

[0073] When appropriately replaced by a corresponding process, some or all of the structural features of the apparatus described above, in detail in the "Detailed Description," or as defined in the claims can be combined with the implementation of the method of the present invention, and vice versa. The implementation of the method has the same advantages as the corresponding apparatus.

[0074] Directional data may include a directional index or a front-to-back ratio.

[0075] Computer-readable media or data carrier

[0076] The present invention further provides a tangible computer-readable medium (data carrier) storing a computer program including program code (instructions), which, when the computer program is run on a data processing system (computer), causes the data processing system to perform (implement) at least some (such as most or all) of the steps of the methods described above, in detail in the "Detailed Description" and as defined in the claims.

[0077] By way of example, but not limitation, the aforementioned tangible computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to execute or store required program code in the form of instructions or data structures and is accessible by a computer. As used herein, disks include compact discs (CDs), laser discs, optical discs, digital multipurpose discs (DVDs), floppy disks, and Blu-ray discs, wherein these disks typically magnetically copy data while simultaneously being optically copied using lasers. Other storage media include those stored in DNA (e.g., in synthetic DNA strands). Combinations of the aforementioned disks should also be included within the scope of computer-readable media. In addition to being stored on tangible media, computer programs may also be transmitted via transmission media such as wired or wireless links or networks such as the Internet and loaded into data processing systems to run at locations other than tangible media.

[0078] Computer program

[0079] In addition, this application provides a computer program (product) including instructions that, when run by a computer, cause the computer to perform the steps of the methods (methods) described above, in detail in the "Detailed Description" section, and as defined in the claims.

[0080] Data processing system

[0081] In one aspect, the present invention further provides a data processing system, including a processor and program code, the program code causing the processor to perform at least some (such as most or all) of the steps of the methods described above, in detail in the "Detailed Description" section, and as defined in the claims.

[0082] Hearing aid system

[0083] On the other hand, this application provides a hearing aid system suitable for wear by a user, the hearing aid system including at least one hearing aid and at least one additional device. The hearing aid system further includes:

[0084] - At least two microphones that provide at least two electrical input signals corresponding to the sounds around the user wearing the hearing aid system;

[0085] - A filter bank that converts at least two electrical input signals into signals that are functions of time and frequency, for example, represented by a complex-valued time-frequency unit;

[0086] - A directional system connected to at least two microphones, configured to provide a filtered signal based on at least two electrical input signals and fixed or adaptively updated beamformer weights; and

[0087] - Transceiver circuitry, used to establish a communication link that enables the exchange of data between the hearing aid and at least one other device.

[0088] The hearing aid system can be configured such that:

[0089] - At least one direction toward the target sound source is defined as the target direction;

[0090] - For each frequency band, one of the at least two microphones is selected as the reference microphone at a given time point, thereby providing a reference input signal for each frequency band.

[0091] For a target sound incident on the hearing aid from a target direction at a given time point, a reference microphone for a given frequency band can be selected at the given time point based on directional data related to the directional characteristics of the at least two microphones.

[0092] For at least two frequency bands, the reference microphones can be different.

[0093] Directional data may include a directional index or a front-to-back ratio.

[0094] At least one additional device may include a second hearing aid. Each of the first and second hearing aids may include at least one of at least two microphones.

[0095] At least one additional device may include an assistive device or be configured to exchange data with an assistive device, the assistive device including a user interface for the hearing aid system. The assistive device may be a portable communication device such as a telephone (e.g., a smartphone, smartwatch, or tablet computer) or may include a portable communication device such as a telephone (e.g., a smartphone, smartwatch, or tablet computer). The hearing aid system may be configured to enable data exchange between the user interface of the assistive device and (the first) hearing aid and / or the second hearing aid.

[0096] A hearing aid system may include first and second hearing aids and an assistive device. Alternatively, the hearing aid system may include first and second hearing aids and be configured to exchange data with the assistive device.

[0097] This application further provides a binaural hearing aid system. The binaural hearing aid system includes a first hearing aid described above, in detail in the "Detailed Description" section, and as defined in the claims, and a second hearing aid described above, in detail in the "Detailed Description" section, and as defined in the claims. The first and second hearing aids are configured as a binaural hearing aid system, thereby enabling data exchange between the first and second hearing aids.

[0098] The reference microphone can be selected based on the intended application of the filtered signal. Different intended applications of the filtered signal may include a) self-voice detection, b) self-voice estimation, c) keyword detection, d) target signal cancellation, target signal focusing, noise reduction, etc.

[0099] The reference microphone can be selected independently in the first and second hearing aids, and the binaural hearing aid system can be configured to select a reference microphone for the first hearing aid from at least two microphones in the first hearing aid. Similarly, the binaural hearing aid system can be configured to select a reference microphone for the second hearing aid from at least two microphones in the second hearing aid.

[0100] A binaural hearing aid system may include an assistive device. The binaural hearing aid system may be adapted to establish a communication link between the first and / or second hearing aid and the assistive device so that information (such as control and status signals, possibly audio signals) can be exchanged or forwarded from one device to another.

[0101] Auxiliary devices may include remote controls, smartphones, or other portable or wearable electronic devices such as smartwatches.

[0102] The assistive device may consist of or include a remote control for controlling the functions and operation of the hearing aid. The remote control functionality is implemented in a smartphone, which may run an app that enables control of the audio processing device via the smartphone (the hearing aid includes a suitable wireless interface to the smartphone, such as Bluetooth or some other standardized or proprietary solution).

[0103] The assistive device may be constituted by or include an audio gateway device, which is adapted to receive multiple audio signals (e.g., from an entertainment device such as a TV or music player, from a telephone device such as a mobile phone, or from a computer such as a PC) and to select and / or combine appropriate signals (or combinations of signals) from the received audio signals to transmit to the hearing aid.

[0104] APP

[0105] On the other hand, the present invention also provides a non-transitory application called an APP. The APP includes executable instructions configured to run on an assistive device to implement a user interface for the hearing aid or hearing aid system or binaural hearing aid system described above, in detail in the "Detailed Description," and as defined in the claims. The APP can be configured to run on a mobile phone, such as a smartphone, or another portable device enabled to communicate with said hearing aid or hearing system. Attached Figure Description

[0106] Various aspects of the invention will be best understood from the following detailed description taken in conjunction with the accompanying drawings. For clarity, these drawings are schematic and simplified, showing only the details necessary for understanding the invention while omitting other details. Throughout the specification, the same reference numerals are used for the same or corresponding parts. Features of each aspect may be combined with any or all features of other aspects. These and other aspects, features, and / or technical effects will be apparent from and illustrated in the following figures, wherein:

[0107] Figure 1A The typical position of the microphone in a behind-the-ear (BTE) hearing aid is shown;

[0108] Figure 1B The typical location of the microphone in an in-the-ear (ITE) hearing device is shown;

[0109] Figure 2A-2C The diagram schematically illustrates the difference between the directivity index of the front microphone and the directivity index of the rear microphone for three different target directions;

[0110] Figures 3A-3C The selection of reference microphones based on the highest directivity index is schematically shown for three different target directions;

[0111] Figure 4 A block diagram illustrating an embodiment of a hearing aid according to the present invention is shown;

[0112] Figure 5 An embodiment of the hearing aid according to the invention is shown communicating with an assistive device including a user interface for the hearing aid, wherein the hearing aid includes a BTE portion located behind the user's ear and an ITE portion located in the user's ear canal;

[0113] Figure 6 An embodiment of a binaural hearing aid system according to the present invention is shown.

[0114] The further applicability of the invention will become apparent from the detailed description given below. However, it should be understood that while the detailed description and specific examples illustrate preferred embodiments of the invention, they are given for illustrative purposes only. Other embodiments of the invention will become apparent to those skilled in the art based on the following detailed description.

[0115] The present invention can be used, for example, in applications such as hearing aids or headphones. Detailed Implementation

[0116] The detailed description below, taken in conjunction with the accompanying drawings, serves as a description of various different configurations. This detailed description includes specific details to provide a thorough understanding of several different concepts. However, it will be apparent to those skilled in the art that these concepts can be implemented without these specific details. Several aspects of the apparatus and method are described by various different blocks, functional units, modules, elements, circuits, steps, processes, algorithms, etc. (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.

[0117] Electronic hardware may include microelectromechanical systems (MEMS), (e.g., application-specific integrated circuits), microprocessors, microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), gating logic, discrete hardware circuits, printed circuit boards (PCBs) (e.g., flexible PCBs), and other suitable hardware configured to perform the various functions described in this specification, such as sensors for sensing and / or recording the physical properties of the environment, devices, users, etc. Computer programs should be interpreted broadly as instructions, instruction sets, code, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, programs, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description languages, or other names.

[0118] This application relates to the field of hearing aids, and more particularly to hearing aids comprising multiple (e.g., ≥2) input transducers (e.g., microphones) and a directional system for providing spatially filtered (beamforming) signals based on signals from the input transducers. In terms of directivity, noise is typically attenuated using beamforming. In MVDR (Minimum Variance Distortion-Free Response) beamforming, for example, the microphone signal is processed such that the sound incident from the target direction at a selected reference microphone is not altered.

[0119] The microphones of hearing aids (M1, M2) are both located near the ear canal, such as behind the ear. Figure 1A or at the entrance of the ear canal ( Figure 1B (or a combination thereof). To preserve the user's spatial positioning cues (such as the time and level difference between the ears, or even positioning cues related to the auricle), the microphone needs to be placed close to the user's ear canal.

[0120] Both microphones (M1 and M2) are located within the hearing instrument, with M1 being closest to the user's front and M2 being closest to the user's back. Therefore, M1 is called the front microphone and M2 is called the rear microphone.

[0121] Due to their proximity to the head and ears, different microphones may have different directional characteristics. Directional characteristics can be measured, for example, based on the directivity index, the front-to-back ratio, or any other ratio between the target direction and the non-target direction (of the signal content).

[0122] The directivity index DI is given by the ratio of the response in the target direction θ0 to the responses in all other directions:

[0123]

[0124] The front-to-back ratio (FBR) is the ratio between the response in the front half-plane and the response in the back half-plane.

[0125]

[0126] Alternatively, a ratio other than the front-to-back ratio can be used, such as the ratio between the amplitude response (e.g., power density) in a smaller angular range (<180°) of the target direction and the amplitude response in a larger angular range (>180°, remaining) of the non-target direction (and vice versa). The directivity index or front-to-back ratio can be estimated for different types of isotropic noise fields, such as spherical isotropic noise fields (noise from all directions is equally likely) or cylindrical isotropic noise fields (noise field is equally likely in the horizontal plane). Typically, isotropic noise fields are isotropic only when the head is absent. Isotropic noise fields can change due to the head and auricle, causing the energy distribution to differ across the uniformly sampled directions.

[0127] Figure 2A , 2B Figures 2 and 2C illustrate examples of the (frequency-dependent) differences in the directivity index of the front microphone M1 and the rear microphone M2 for three different directions toward a target sound source. The directivity of the microphones varies depending on their placement, such as behind the ear or near the ear canal. The orientation of the front and rear microphones relative to the user's head (e.g., nose) is... Figure 2A As shown in the illustration at the top right. The direction relative to the user's target sound source is... Figure 2A , 2B The three curves for 2C are indicated on the left by small insets with heads and arrows. The target sound source is located in the front half-plane. Figure 2A The target sound source is positioned directly in front of the user (+90°). The target sound source is located in the front half-plane. Figure 2B The target sound source is located to the user's left (approximately +135°). The target sound source is situated in the rear half-plane. Figure 2C The center is directly behind the user (+270°).

[0128] from Figure 2A , 2B As can be clearly seen from Figure 2C, the microphone with the highest directivity index depends on the target direction and frequency. Therefore, it is advantageous to select a reference microphone based on the microphone's directivity characteristics.

[0129] For targets incident from the front, the front microphone M1 typically has higher directivity, while the rear microphone M2 typically has higher directivity when the target speaker is behind the listener. We also note the cross-frequency variation of the microphone with the highest directivity.

[0130] As an alternative to using a directivity index, the transfer function between microphones can be considered. For a given frequency band k, the reference microphone can be selected based on the microphone that picks up the most energy from the target direction.

[0131] For the propagation of sound from a given location to M microphones of a hearing aid (or hearing aid system), the normalized relative transfer function d m (k)(m=1,…,M) can be written as a vector d=[d1,d2,….,d M (Sometimes called the "steering vector" or view vector), where the transfer function of the reference microphone (subscript m = 'ref') has a value d. ref =1, and all other elements of d (m≠'ref') have a value less than 1.

[0132] This can be advantageous if the relative transfer function from the target direction can be adaptively estimated during use.

[0133] This invention proposes a method for selecting a reference microphone (or reference signal), wherein the selection of the reference microphone (or reference signal) can vary across the target direction and frequency band.

[0134] Hearing aids may include:

[0135] - At least two microphones;

[0136] - A filter bank that converts microphone signals into signals that are functions of time and frequency, such as complex-valued time-frequency units;

[0137] - A directional system with a selected reference microphone for each frequency band;

[0138] - Access the direction data of the microphone on the hearing instrument;

[0139] - Defined as a direction or a set of directions of the target direction;

[0140] -The reference microphone for a given frequency band is selected based on the microphone's direction data.

[0141] In this embodiment, the selected reference microphone adapts to the estimated target direction.

[0142] In one embodiment, the reference microphone selected in a frequency band is a microphone that has the highest directivity index for a given target direction or the highest ratio between the selected target direction and the selected noise direction.

[0143] In this embodiment, the directional system is implemented as an MVDR beamformer.

[0144] Figure 3A , 3B 3C shows the three different target directions (with) Figure 2A , 2B (Same as in 2C), the reference microphone is selected based on the highest directivity index. A thick line indicates the front microphone as the selected reference microphone, and a dashed line indicates the rear microphone as the selected reference microphone. Figure 3A , 3B In the schematic diagram of 3C, the reference microphone for a given frequency band and a given direction to the target sound source is selected as the microphone with the maximum directivity index.

[0145] Figure 4 A block diagram illustrating an embodiment of a hearing aid according to the present invention is shown. The hearing aid HD includes an exemplary dual-microphone beamformer configuration BF according to the present invention. The hearing aid includes first and second microphones (M1, M2) for converting input sound into a first electrical input signal IN1 and a second electrical input signal IN2, respectively. The forward direction is defined, for example, by the microphone axis of the hearing aid when the hearing aid is mounted on the user, such as... Figure 4The direction from the target signal S (target sound) to the hearing aid microphones (M1, M2) is indicated by dotted arrows labeled h1 and h2, respectively. The first and second microphones (when located at the user's ear) are represented by time-domain impulse responses. and (Or in the frequency domain, the transfer function) and Characterization. The impulse response (h1,h2) (or transfer function (H1,H2)) represents the sound emitted from the area surrounding the hearing aid. The acoustic properties of the corresponding “propagation channels” from the (target) sound source S to the first and second microphones (M1, M2) of the hearing aid (when the hearing aid is installed on the user). Figure 4 The hearing aid embodiment is configured to operate in the time-frequency domain. Therefore, the hearing aid includes first and second analysis filter bank units (FBA1 and FBA2), which are configured to convert first and second time-domain signals IN1 and IN2 into time-frequency domain signals IN1 and IN2, respectively. m (k), m=1,2, and k=1,…,K, where K is the number of frequency bands (the time exponent is omitted for simplicity). The number M of input converters (such as microphones) can be greater than 2.

[0146] The hearing aid HD also includes a directional system (beamformer filter) BF, used to provide the beamformed signal Y(k) as a weighted combination of the first and second electrical input signals IN1, IN2 using (typically complex) filter coefficients (also known as beamformer weights) W1(k) and W2(k): Y(k) = W1(k)IN1(k) + W2(k)IN2(k), k = 1,…,K. Figure 4 In the process, filter coefficients W1(k) and W2(k) are applied to the input signals IN1(k) and IN2(k), respectively, in the corresponding multiplication units ('x'), k = 1, ..., K. In the corresponding summation units ('+'), terms with the same frequency exponent (W1(k)IN1(k) and W2(k)IN2(k)) are added, k = 1, ..., K. The outputs of the K summation units provide the sub-band signal Y(k) of the beamforming signal, k = 1, ..., K. The number of bands K can be greater than 1, for example, in the range of 4 to 128.

[0147] The hearing aid (e.g., a directional system in this case) includes a memory MEM containing values ​​of parameters suitable for controlling the directional system. At least some of these parameters can be predefined and stored before the hearing aid is used. At least some of these parameters can be updated and stored during use. The first and second microphones are positioned for different directions toward the target sound source (e.g., see...). Figure 2AThe directional characteristics of the first and second microphones (M1, M2) can be stored in memory. The hearing aid (e.g., a directional system in this case) may include a reference signal and beamformer weight calculation unit REF->WGT-CALC for providing beamformer weights (W1(k) and W2(k), k = 1, ..., K) based on the directional characteristics of the first and second microphones (M1, M2). The memory unit MEM may contain the directional characteristics of the first and second microphones for different directions (TD) to the target sound source (e.g., for each frequency band k = 1, 2, ..., K), see, for example, the signal DIRC(k, TD) between the memory MEM and the REF->WGT-CALC module. The directional characteristics may include, for example, a directivity index (DI) or front-to-back ratio (FBR) or similar parameters that can be determined as a frequency-varying indication of the directional characteristics for a given microphone configuration. For a given frequency band k, a reference signal for a given direction to the target sound source can be extracted from the directional characteristics, for example, based on a predefined threshold. The memory may include a direction (TD) for each target sound source and a reference indication parameter REF(k,TD) for each frequency band (k) for its stored directional characteristics. The reference indication parameter for a given target direction (TD) and frequency band (k) indicates whether (or with what probability) a given microphone signal is a reference signal. Given a target direction (TD), the REF->WGT-CALC module can read the corresponding DIRC(k,TD) value from the memory MEM or simply read the reference indication parameter REF(k,TD).

[0148] The filter coefficients W1(k) and W2(k), k = 1, ..., K, for different directions to the target signal can be adaptively determined based on the first and second electrical input signals (IN1(k), IN2(k)), the target direction (θ), and the reference indication parameter REF(k, θ) for that target direction (θ). The target direction (θ) at a given time point can be provided, for example, via the user interface (UI), see the signal TD from the user interface to the reference signal and beamformer weight calculation unit REF->WGT-CALC (shown by the dashed arrow). The target direction at a given time point can be adaptively estimated, for example, in the reference signal and beamformer weight calculation unit REF->WGT-CALC based on the first and second electrical input signals (IN1(k), IN2(k)) and the signal statistics extracted from them (e.g., covariance matrix, acoustic transfer function, etc., for example, using a voice activity detector to classify the current acoustic environment to estimate the noise and speech properties of the current input signal), see, for example, EP2701145A1 or [Brandstein & Ward; 2001].

[0149] Weights can be calculated in a similar manner to how weights are typically discovered. For example, for MVDR beamformers,

[0150]

[0151] in R is the inter-microphone noise covariance matrix v The estimated quantity, This is an estimate of the steering (or look-through) vector d for frequency band k. However, the magnitude of the weights will depend on how the relative transfer function d is scaled. For example, if d is scaled to maximize its value to 1, such as d = [1, z], then the weights will be calculated as the maximum values ​​of the individual components of d. T Or d = [z, 1] T (For a dual-microphone configuration), where |z| < 1, this can be advantageous. This allows the weight w to become smaller, and consequently, the white noise gain (microphone noise) becomes smaller.

[0152] Of course, beamformer weights can be optimized using other optimization conditions different from those for MVDR beamformers, such as the more general conditions for linearly constrained minimum variance (LCMV) beamformers.

[0153] Another advantage is that it can provide fading towards the reference microphone signal (for a given frequency band k, k = 1, ..., K) without requiring noise reduction. Possible fading types include...

[0154] w applied (k)=α*w mvdr (k)+(1-α)*w ref (k)

[0155] Where w applied (k) is the weight vector applied to the microphone, w mvdr (k) is the weight vector estimated for applying maximum noise reduction, w ref (k) is a vector whose exponents contain 0 in all cases except the reference microphone (with a value of 1 for the reference microphone), and α is a value between 0 (resulting in the reference microphone signal) and 1 (resulting in maximum noise reduction). The fading weight α can remain constant across the frequency range. However, it can also vary with frequency (α(k)).

[0156] Figure 4The hearing aid includes a dual-microphone beamformer configuration comprising a signal processor SPU for (further) processing the beamformed signal Y(k) in K frequency bands and providing a processed signal OU(k), k = 1, 2, ..., K. The signal processor may be configured, for example, to apply one or more processing algorithms to the signal in the forward path, such as applying level and frequency shaping of the beamformed signal, for example, to compensate for the user's hearing loss. The processed frequency band signal OU(k) is fed to a synthesis filter bank FBS for converting the frequency band signal OU(k) into a single time-domain processed (output) signal OUT, which is fed to an output unit to be presented to the user as a signal perceptible as sound. Figure 4 In one embodiment, the output unit includes a speaker SPK for presenting the processed signal OUT to the user as sound (e.g., vibrations propagating through the air). The microphone (M) of the hearing aid... BTE1 M BTE2 The forward path from the speaker SPK (primarily) operates in the time-frequency domain (in K frequency bands).

[0157] Figure 5 An embodiment of the hearing aid according to the invention is shown communicating with an assistive device including a user interface for the hearing aid, wherein the hearing aid includes a BTE portion located behind the user's ear and an ITE portion located in the user's ear canal.

[0158] Figure 5 An embodiment of a hearing device HD, such as a hearing aid, according to the present invention is shown, which communicates with an assistive device AUX including a user interface UI for the hearing device and includes a BTE portion located behind the user's ear and an ITE portion located in the user's ear canal. Figure 5 An exemplary hearing aid HD, configured as an in-ear receiver type (RITE) hearing aid, is shown, comprising a BTE portion adapted to be located at or behind the auricle and an ITE portion (e.g., exemplified by...) including an output transducer (such as a speaker / receiver) adapted to be located in the user's ear canal. Figure 4 The hearing aid shown is an HD. The BTE section and the ITE section are connected via a connecting element IC (e.g., an electrical connection). Figure 5 In this hearing aid embodiment, the BTE section includes two input transducers (here, microphones) (M1, M2), each input transducer providing a representation of the ambient sound (in... Figure 5 In the case of an input sound signal (including the sound source S), the input audio signal is an electrical input signal.

[0159] Figure 5The hearing aid HD also includes two wireless receivers or transceivers, WLR1 and WLR2, for providing corresponding directly received auxiliary audio and / or information / control signals (optionally, and for transmitting such signals to other devices). The hearing aid HD includes a substrate SUB on which multiple electronic components are mounted and functionally divided according to the application involved (analog, digital, passive components, etc.), but includes a signal processor DSP, a front-end chip FE, and a memory unit MEM, all interconnected by electrical conductors Wx and connected to input and output units. The mentioned functional units (and other components) can be divided by circuit and component according to the application involved (e.g., for size, power consumption, analog-to-digital processing, radio communication, etc.), for example, integrated into one or more integrated circuits, or as a combination of one or more integrated circuits and one or more individual electronic components (such as inductors, capacitors, etc.). The signal processor DSP provides enhanced audio signals (see...). Figure 4 The signal OUT in the middle (which is the plan to present to the user). Figure 5 In the hearing aid embodiment, the ITE section includes an output unit in the form of a speaker (receiver) SPK for converting an electrical signal OUT into an acoustic signal (thereby providing or contributing an acoustic signal S to the eardrum). ED The ITE section may also include one or more input transducers (such as microphones). ITE The hearing aid includes an input unit for providing an electrical input audio signal representing an input sound signal from the environment at or within the ear canal. In another embodiment, the hearing aid may include only BTE microphones (M1, M2). In yet another embodiment, the hearing aid may include a combination of an input unit (e.g., a microphone or vibration sensor) located elsewhere from the ear canal entrance (e.g., towards the eardrum) and one or more input units located in the BTE portion and / or ITE portion. The ITE portion also includes a guiding element such as a dome DO for guiding and positioning the ITE portion within the user's ear canal.

[0160] Figure 5 The hearing aid HD illustrated is a portable device and also includes a battery BAT for powering the electronic components of the BTE and ITE sections.

[0161] Hearing aids (HD) include a directional microphone system (beamformer filter) Figure 4 The beamforming signal Y(k) is adapted to enhance the target sound source among multiple sound sources in the local environment of a hearing aid user. The memory unit MEM may include predetermined (or adaptively determined) complex numbers, frequency-varying constants, which define predetermined (or adaptively determined) or "fixed" beam patterns, directional data such as reference indicators, etc., and together define or facilitate the calculation or selection of appropriate beamformer weights based on the current electrical input signal, thus beamforming the signal Y(k) (see, for example, [link to relevant documentation]). Figure 4 ).

[0162] Figure 5 The hearing aid may constitute or form part of the hearing aid and / or binaural hearing aid system according to the present invention.

[0163] The hearing aid HD according to the present invention may include a user interface (UI), such as... Figure 5 The lower middle section shows an app implemented in an auxiliary device AUX such as a remote control, for example, in a smartphone or other portable (or stationary) electronic device. Figure 5 In this embodiment, the user interface (UI) screen displays the target direction app. The direction TD to the target sound source S of interest to the user can be selected from the user interface, for example, by dragging the sound source symbol S to the direction relevant to the user's current location. The currently selected target direction is the forward direction, as indicated by the thick arrow (denoted as TD) to the sound source S. The assistive device AUX and hearing aid are adapted to enable the transmission of data representing the currently selected direction via, for example, a wireless communication link (see [link to [link to [link to [link]]). Figure 5 The wireless transceiver WLR2 (dashed arrow WL2) transmits information to the hearing aid. The communication link WL2 may be based on far-field communication, such as Bluetooth or Bluetooth Low Energy (or similar technologies), implemented via appropriate antenna and transceiver circuitry in the hearing aid HD and assistive device AUX, and is indicated by the transceiver unit WLR2 in the hearing aid. Other aspects related to the control of the hearing aid (e.g., beamformer) may be made selectable or configurable from the user interface (UI).

[0164] Figure 6 An embodiment of a binaural hearing aid system according to the present invention is shown. This hearing aid system is adaptable for wear by a user U. The hearing aid system includes first and second hearing aids (HD1, HD2), each adapted to be placed at or within the user's ear. Each of the first and second hearing aids includes at least two (in this case, two) microphones (M1, M2), which respectively provide first and second (e.g., digitized) electrical input signals (IN1, IN2) representing the sound surrounding the user U wearing the hearing aid system. The first and second microphones (M1, M2) may form part of a linear or nonlinear microphone array. Figure 6In this embodiment, the first and second microphones (M1, M2) form a microphone axis parallel to the user's line of sight (see the arrow denoted as LOOK-DIR) when the hearing aids (HD1, HD2) are mounted at the user's ear (see the schematic user U between the first and second hearing aids). Each of the first and second hearing aids (HD1, HD2) includes first and second analysis filter banks (FBA1, FBA2) for converting at least two electrical input signals (IN1, IN2) into sub-band signals (IN1, IN2) as functions of time (l) and frequency (k), represented, for example, by complex-valued time-frequency units (k, l) arranged in consecutive time frames, each time frame including the spectrum of the signal at a specific time l'. The spectrum at a given time l' may, for example, include complex values ​​(magnitude and phase) of the signal at multiple frequencies k = 1, ..., K, where K is the number of frequency windows in the spectrum (provided, for example, by a Fourier transform algorithm). Each of the first and second hearing aids (HD1, HD2) includes a directional system BF (beamformer filter) that receives two electrical input signals (IN1, IN2) from the microphones (M1, M2) of the hearing aid itself, and signals received via a wireless link (see the dashed double arrow denoted as IA-WL) from another hearing aid in the hearing aid system (or via a wireless link (e.g., via a dashed double arrow)). Figure 5 WL2 in the middle) communicates with another device (e.g., the hearing aid in question) from the other device that communicates with the hearing aid in question. Figure 5 (AUX in a smartphone) and at least one other electrical input signal (IN) HD2 For example, signals from a microphone or beamforming signals). The directional system BF is configured to respond to at least three electrical input signals (IN1, IN2, IN3, IN4, IN5, IN6, IN7, IN8, IN9, IN1 ...1, IN1, IN2, IN3, IN4, IN5, IN6, IN1, IN1, IN HD2 ) and fixed or adaptively updated beamformer weights (W1, W2, W HD2 The first and second hearing aids (HD1, HD2) provide a filtered signal Y. Each of these includes appropriate transceiver circuitry Rx / Tx for establishing a communication link IA-WL, thereby enabling the exchange of data (e.g., audio data IN) between the first and second hearing aids (HD1, HD2). HD1 IN HD2The hearing aid system includes, for example, one or more microphone signals (IN1, IN2) or combinations thereof, in the form of one or more spatially filtered signals (or portions thereof, such as their selected frequency ranges). The hearing aid system is configured such that the direction of arrival (TD) to at least one target sound source is defined as the target direction (and provided via the user interface UI (see the dashed arrow between the signal TD and the user interface UI and the module REF->WGT-CALC)) and / or estimated by an algorithm of the hearing aid (e.g., in the module REF->WGT-CALC)). Several algorithms for estimating the direction of arrival (DOA) of the target (speech) signal have been proposed in the prior art (e.g., see EP3413589A1). The directional system BF includes a reference signal and a beamformer weight calculation unit REF->WGT-CALC, which is configured to receive at least three electrical input signals (IN1, IN2, IN3, IN4, IN5, IN6, IN7, IN8, IN9 ... HD2 For each frequency band (k, k = 1, ..., K), a reference input signal is selected (and this selection is adaptively updated over time based on the current direction to the target signal source). Hearing aids (e.g., directional systems, BF) may include a speech activity detector to estimate whether or with what probability the input signal includes a speech signal at a given time point. Thus, a frequency-varying filter weight W based on the noise covariance matrix (R0) can be provided (for example, in an MVDR beamformer). v Adaptive estimations of the transfer function (d, when speech is not present) and the transfer function (d, when speech is detected):

[0165]

[0166] in R is the inter-microphone noise covariance matrix v In the estimator of frequency band k, This is an estimate of the steering (or visual) vector d for frequency band k. The hearing aid (e.g., a directional system BF) is configured to continuously update the selection of the reference signal (and filter coefficients) based on the current electrical input signal (and thus the direction to the target sound source of the user's current interest). The direction to the target signal can be provided by the user via a user interface and / or adaptively determined by the hearing aid, for example, based on the electrical input signal and a voice activity detector. The reference microphone signal for a given frequency band k can be determined according to specific (e.g., logical) criteria, such as direction data from the corresponding physical or virtual microphone, or according to an estimate of the acoustic transfer function d(k) of the current target direction (TD), see the arrow denoted as TD from the target signal source S to the user U. The acoustic transfer function d(k) (e.g., the relative acoustic transfer function) for multiple predetermined target directions (TD), frequency-varying directional data (e.g., directivity index or front-to-back ratio) or estimates, can be stored in the hearing aid's memory MEM (or in an external database accessible via a communication link) for use in estimating a reference microphone signal for a given frequency band and subsequently determining the filter weights W(k) between the memory MEM and the reference signal and the beamformer weight calculation unit REF->WGT-CALC (see signal P(k,TD)). The target direction (TD) can be denoted as the angle θ in the horizontal plane (e.g., through the user's ear) from the center of the user's head to the target sound source S of interest to the user U.

[0167] exist Figure 6 In the embodiment, the reference signal of the first hearing aid (HD1) and the beamformer weight calculation unit REF->WGT-CALC are configured to determine the filter weights W1, W2, W... HD2 The weights are then applied to the corresponding electrical input signals IN1, IN2, IN3 via the corresponding combination unit (multiplication unit 'x'). HD2 The resulting weighted signals are combined in the combining unit (summing unit '+') to provide the filtered (beamforming) signal Y. The reference signal of the second hearing aid (HD2) and the beamformer weight calculation unit REF->WGT-CALC are configured to correspondingly provide the filter weights W1, W2, W... HD1 These filter weights are applied to the (local) input signals IN1, IN2 and the signal IN received from the first hearing aid. HD1 .

[0168] The spatially filtered (beamforming) signal Y (varying with frequency) can be further processed in the hearing aid signal processor (SPU) of the forward path, for example, to adapt to the user's hearing loss (at the ear involved). The frequency dependence of the filtered signal Y is schematically illustrated by different shaded beamformers associated with Y, denoted as k = 1, ..., K. The forward path also includes a synthesis filter bank (FBS) for converting the frequency-domain processed signal, which is split into frequency bands, into a processed time-domain signal OUT (possibly after digital-to-analog conversion, if appropriate) fed to the output converter (here, the speaker SPK) to be presented as a stimulus (here, an acoustic stimulus) that can be perceived as sound by the user U.

[0169] exist Figure 6 In the embodiments, the first and second hearing aids (HD1, HD1) may be the same, except that they may be specifically adapted to the user’s left and right ears (e.g., depending on the possible different hearing conditions of the user’s left and right ears, resulting in the application of different parameterized compression algorithms (and possibly other algorithms) in the hearing aid signal processor SPU in the forward path).

[0170] Instead of selecting a reference microphone signal based on microphone position characteristics (e.g., direction data or acoustic transfer function), a hearing aid or (potentially binaural) hearing aid system can be adapted (e.g., in a specific operating mode, e.g., selected from a user interface UI) to select a reference microphone based on the planned application of the filtered signal Y. Different planned applications of the filtered signal may include, for example, a) self-voice detection, b) self-voice estimation, c) keyword detection, d) target signal cancellation, target signal focusing, noise reduction, etc.

[0171] Furthermore, the binaural hearing aid system can be adapted (e.g., in “monaural operation mode”, e.g. via user interface UI input) to independently select a reference microphone (or reference microphone signal) in the first and second hearing aids (e.g., select only in “its own microphone”).

[0172] When appropriately replaced by a corresponding process, the structural features of the apparatus described above, in detail in the "Detailed Description" section, and as defined in the claims can be combined with the steps of the method of the present invention.

[0173] Unless explicitly stated otherwise, the singular forms “a” and “the” used herein include the plural forms (i.e., meaning “at least one”). It should be further understood that the terms “having,” “comprising,” and / or “including” as used in the specification indicate the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. It should be understood that, unless explicitly stated otherwise, when an element is referred to as “connected” or “coupled” to another element, it may be a direct connection or coupling to the other element, or there may be intermediate inserting elements. The term “and / or” as used herein includes any and all combinations of one or more of the listed related items. Unless explicitly stated otherwise, the steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed.

[0174] It should be understood that references to "an embodiment," "an embodiment," "an aspect," or "may" in this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. Furthermore, particular features, structures, or characteristics may be suitably combined in one or more embodiments of the invention. The foregoing description is provided to enable those skilled in the art to implement the various aspects described herein. Various modifications will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects.

[0175] The claims are not limited to the aspects shown herein, but encompass the full scope consistent with the language of the claims, wherein, unless expressly stated, an element referred to in the singular does not mean "one and only one," but rather "one or more." Unless expressly stated, the term "some" means one or more.

[0176] The idea described above, which enables a beamformer to select a reference microphone (or reference signal) from a microphone array for cross-band k variation, is illustrated above with a single hearing aid. However, this concept can also be applied to binaural hearing aid systems or systems that include external microphones (e.g., located in one or more external devices such as smartphones). Different combinations of reference microphones can depend on the application of the beamforming signal (the left ear can select a reference microphone only within the range of the left hearing aid microphone, and similarly for the right ear). Furthermore, the beamforming signal used for detection (e.g., keywords) can be selected from all available microphones in the microphone array.

[0177] References

[0178] ·EP3229489A1(Oticon)11.10.2017

[0179] ·EP2701145A1(Retune,Oticon)26.02.2014.

[0180] ·[Brandstein&Ward;2001]M.Brandstein and D.Ward,"Microphone Arrays",Springer 2001.

[0181] ·EP3413589A1(Oticon)12.12.2018。

Claims

1. A hearing aid suitable for wear by a user in or in the ear, or partially or completely implanted in the head in the ear, said hearing aid comprising: - At least two microphones that provide at least two electrical input signals corresponding to the sounds around the user wearing the hearing aid; - A filter bank that converts at least two electrical input signals into signals that are functions of time and frequency; - A directional system connected to at least two microphones, configured to provide a filtered signal based on at least two electrical input signals and fixed or adaptively updated beamformer weights; and - The direction towards the target sound source is defined as the target direction; Wherein, for each frequency band, one of the at least two microphones is selected as a reference microphone at a given time point, thereby providing a reference input signal for each frequency band; wherein, for a target sound incident on the hearing aid from a target direction at a given time point, the reference microphone for the given frequency band is selected at the given time point based on directional data related to the directional characteristics of the at least two microphones.

2. The hearing aid according to claim 1, wherein, Adaptive selection of reference microphones for a given frequency band.

3. The hearing aid according to claim 2, wherein, The reference microphone for a given frequency band is adaptively selected based on logical criteria.

4. The hearing aid according to claim 1, comprising: - A memory or circuitry for establishing a communication link to a database, which includes directional data relating to the directional characteristics of at least two microphones; The reference microphone for a given frequency band is adaptively selected based on the directional data.

5. The hearing aid according to claim 1, wherein, The directional data includes a directional index or a front-to-back ratio.

6. The hearing aid according to claim 5, wherein, For a target sound incident on the hearing aid from the target direction at a given time point, a reference microphone for a given frequency band is selected as the microphone that exhibits the maximum directivity index or the maximum front-to-back ratio at that given time point.

7. The hearing aid according to claim 1, wherein, The directional system is implemented as or includes a minimum variance distortion-free response (MVDR) beamformer, depending on the selected reference microphone.

8. The hearing aid according to claim 1, wherein, The target direction is provided via the user interface.

9. The hearing aid of claim 1, configured to estimate the target direction.

10. The hearing aid of claim 1, further comprising a speech activity detector for estimating whether or with what probability the input signal includes a speech signal at a given time point.

11. The hearing aid according to claim 1, wherein, The hearing aid is an air conduction hearing aid, a bone conduction hearing aid, a cochlear implant hearing aid, or a combination thereof.

12. A binaural hearing aid system comprising a first hearing aid according to any one of claims 1-11 and a second hearing aid according to any one of claims 1-11, wherein the first and second hearing aids are configured as a binaural hearing aid system to enable data exchange between the first and second hearing aids.

13. The hearing aid system according to claim 12, wherein, The reference microphone is selected based on the planned application of the filtered signal.

14. The hearing aid system according to claim 12, wherein, The reference microphone is selected independently in the first and second hearing aids.

15. A method of operating a hearing aid, the hearing aid being adapted for wear by a user in or in the user's ear or partially or completely implanted in the head in the user's ear, the hearing aid comprising at least two microphones, the method comprising: - Provide at least two electrical input signals, respectively, representing the sounds surrounding the user wearing the hearing aid, through the at least two microphones; - Convert at least two electrical input signals into signals that are functions of time and frequency; - Provide a filtered signal based on at least two electrical input signals and fixed or adaptively updated beamformer weights; and - Define at least one direction toward the target sound source as the target direction; - For each frequency band, at a given time point, one of the at least two microphones is selected as a reference microphone to provide a reference input signal for each frequency band; wherein, for a target sound incident on the hearing aid from a target direction at a given time point, the reference microphone for the given frequency band is selected at the given time point based on directional data relating to the directional characteristics of the at least two microphones.

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