JP2022528579A - Bilateral hearing aid system with temporally uncorrelated beamformer - Google Patents

Abstract

The present invention comprises, in a first aspect, a first hearing aid for placement in or in the user's right ear and a second hearing aid for placement in or in the user's left ear. With respect to a binaural hearing aid system with or vice versa. The first signal processor of the first hearing aid has maximum sensitivity in the target direction based on one or more microphone signals supplied by the first microphone device of the first hearing aid in response to the input sound. It is configured to generate a first monaural beamforming signal indicating a first pole pattern. The first signal processor is additionally configured to generate a bilateral beamforming signal based on the first monaural beamforming signal and the second monaural beamforming signal received from the second hearing aid. The bilateral beamforming signal has a polar pattern with maximum sensitivity in the target direction, typically in front of the user, with reduced sensitivity on the ipsilateral or local side of each of the first and second hearing aids. show. The first signal processor further has maximum sensitivity on the same side of the first hearing aid, reduced sensitivity in the target direction, and first hearing aid based on one or more microphone signals. It is configured to generate a third monaural beamforming signal showing a third pole pattern with reduced sensitivity on the opposite side of the. The first signal processor delays the third monaural beamforming signal with respect to the first bilateral beamforming signal to reduce their correlation and is time-delayed with the first bilateral beamforming signal. It is additionally configured to combine with a third monaural beamforming signal to form a first hybrid beamforming signal. The first, second, and third polar patterns are measured or otherwise determined by the first and second hearing aids attached to the right and left ears of the acoustic model. [Selection diagram] Fig. 2

Description

The present invention relates to, in a first aspect, a first hearing aid for placement in or in the user's right ear and a second hearing aid for placement in or in the user's left ear. With respect to a binaural hearing aid system with the opposite. The first signal processor of the first hearing aid is a first monaural beam forming signal based on one or more microphone signals supplied by the first microphone device of the first hearing aid in response to an input sound. The first monaural beam forming signal exhibits a first polar pattern with maximum sensitivity in the target direction. The first signal processor is further configured to generate a bilateral beamforming signal based on the first monaural beamforming signal and the second monaural beamforming signal received from the second hearing aid. The bilateral beamforming signal has a polar pattern with maximum sensitivity in the target direction, typically in front of the user, with reduced sensitivity on the ipsilateral or local side of each of the first and second hearing aids. show. The first signal processor further generates a third monaural beamforming signal based on one or more microphone signals, and the third monaural beamforming signal has maximum sensitivity on the same side of the first hearing aid. It has, has reduced sensitivity in the target direction, and is configured to show a third polar pattern with reduced sensitivity on the contralateral side of the first hearing aid. The first signal processor further delays the third monaural beamforming signal with respect to the first bilateral beamforming signal to reduce their correlation and time with the first bilateral beamforming signal. It is configured to combine with a delayed third monaural beamforming signal to form a first hybrid beamforming signal. The first, second and third polar patterns are preferably measured or determined with first and second hearing aids attached to the right and left ears of the acoustic manikin.

Deaf people can selectively pay attention to gain audio clarity and maintain situational awareness under noisy listening conditions such as restaurants, bars, concert venues, etc. On the other hand, listening to a particular desired sound source in a noisy environment while maintaining environmental awareness continues to be a daily and difficult task for the hearing impaired. Existing binaural hearing aid systems typically have a measured or objective signal-to-noise ratio of a bilateral or binaurally beam-formed microphone signal to the original microphone signal supplied by the left-ear and right-ear microphone devices. It is effective in improving. Significant signal-to-noise ratio improvements in binaural or binaurally beamformed microphone signals are caused by the high directivity of binaurally beamformed microphone signals. This means that sound sources located outside a relatively narrow angular range around the target direction, typically the user's frontal direction, are significantly attenuated or suppressed. The narrow angular range in which the sound source remains substantially unattenuated can extend only ± 20-40 degrees around the target direction. Such a large suppression of sound sources located outside the target direction leads to a so-called "tunnel hearing" sensation, which is unpleasant for hearing-impaired users who may not hear the sound source outside the target direction, especially situational awareness. Leads to the loss of.

U.S. Pat. No. 8,755,547 discloses a binaural beamforming method and a binaural hearing aid system for enhancing sound intelligibility. The method of improving the intelligibility of the sound is to detect the primary sound emitted from the first direction and generate the primary signal, and to detect the secondary sound emitted from the left side and the right side of the first direction, and the secondary signal. Includes a step of generating the secondary signal, a step of delaying the primary signal relative to the secondary signal, and a step of presenting the signal coupling to the left and right sides of the listener's auditory system. U.S. Pat. No. 8,755,547 makes use of the preceding sound effect only for localization superiority.

In a noisy listening environment, strong beamforming, ie, high directional index, achieves improved speech intelligibility by applying a target direction or range, such as off-axis, i.e. side and back of the user. There is a need in the art for a binoural hearing aid system that provides a flexible way to mitigate the "tunnel hearing" sensation in a less disadvantaged listening environment through the controllable levels of acoustic sources located outside of. Has been done.

The first aspect of the present invention is
A first hearing aid for placement in or within the user's left or right ear, which wirelessly transmits a microphone signal over a first microphone device, a first signal processor, and a data communication channel. And a first hearing aid with a first data communication interface configured to receive.
A second hearing aid for placement in or in the user's opposite ear that wirelessly transmits and transmits microphone signals over a second microphone device, a second signal processor, and a data communication channel. The present invention relates to a second hearing aid comprising a second data communication interface configured to receive, and a binoural hearing aid system comprising. Preferably, the first signal processor is
Based on one or more microphone signals supplied by the first microphone device in response to the input sound, a first monaural beamforming signal indicating a first polar pattern with maximum sensitivity in the target direction is generated. ,
The first monaural beamforming signal is transmitted to the second and contralateral hearing aids via the first wireless communication interface.
A second monaural beamforming signal is received from the second hearing aid via the first wireless data communication interface.
A second polarity pattern showing a second polarity pattern with maximum sensitivity in the target direction and reduced sensitivity on each ipsilateral side of the user's left and right ears, based on the first and second monaural beamforming signals. Generates a bilateral beamforming signal of 1
Based on one or more microphone signals, it has maximum sensitivity on the same side of the first hearing aid, reduced sensitivity in the target direction, and reduced sensitivity on the opposite side of the first hearing aid. It is configured to generate a third monaural beamforming signal indicating a third polar pattern having. The first signal processor further has a third with respect to the first bilateral beamforming signal in order to reduce the correlation between the first bilateral beamforming signal and the third monaural beamforming signal. It is configured to delay the monaural beamforming signal of. The first signal processor further combines or mixes the first bilateral beamforming signal with the time-delayed third monaural beamforming signal to form the first hybrid beamforming signal. The first, second, and third polar patterns are measured at 1 kHz using first and second hearing aids attached to the right or left ear of the acoustic human body model, respectively. It has been decided.

The acoustic mannequin is a commercially available acoustic mannequin such as KEMAR or HATS, or any similar acoustic mannequin designed or constructed to simulate or represent the average acoustic properties of the human head and body. May be good. If the binaural hearing aid system is properly deployed for a hearing-impaired user or patient, the first, second, and third polar patterns are usually properly attached to the acoustic manikin. You will understand that they exhibit substantially the same polar pattern or directivity characteristics as they do. However, references to acoustic anatomical determinations of the first, second and third polar patterns ensure clear and reproducible measurement conditions for these characteristics of this binaural hearing aid system.

The second signal processor of the second hearing aid is preferably configured to perform the corresponding function or algorithm for one or more microphone signals supplied by the second microphone device. The vendor will understand. Therefore, the second signal processor has a characteristic corresponding to the first hybrid beamforming signal formed in the first hearing aid, a second monaural beamforming signal, a corresponding second bilateral beamforming signal, It is configured to form or generate a corresponding fourth monaural beamforming signal and a second hybrid beamforming signal.

Each of the first and second hearing aids or hearing aids comprises a type of hearing aid such as BTE, RIE, ITE, ITC, CIC, RIC and has its associated housing shape and placement in the user's ear.

The characteristics of the first and second hybrid beamforming signals produced by this binaural hearing aid system are perceptually spatialized sound images for off-axis sound sources to facilitate sound source separation. Deliver to hearing aid users. This sound source separation improves the hearing aid user's speech comprehension, listening comfort, and situational awareness in noisy sound environments, such as cocktail party environments, as described in more detail below.

Each of the first and second data communication interfaces preferably has a radio transmitter for transmitting the first and second monaural beam forming signals to the opposite hearing aid, and a second and first monaural beam, respectively. A wireless receiver for receiving a forming signal and a wireless transmitter / receiver are provided. The wireless transceiver may be a wireless transceiver configured to operate in the 2.4 GHz Industrial Science and Medical (ISM) band, or may be compliant with the Bluetooth® LE standard. Alternatively, each of the first and second data communication interfaces may include magnetic coil antennas and may be based on near-field magnetic coupling such as NMFI operating in the frequency domain 10-20 MHz between the antennas. For those skilled in the art, each of the first and second monaural beam forming signals is preferably transmitted in a digitally encoded format, such as a real-time digital audio stream, according to the data protocol of the first and second data communication interfaces. You will understand that. The one or more microphone signals supplied by the first microphone device and the one or more microphone signals supplied by the second microphone device are preferably such that the above-mentioned directional processing step is the first and the first and the plurality of microphone signals. Before being executed by the second signal processor, it is converted into the corresponding digital microphone signal by each A / D converter. Therefore, the beamforming signal described above is preferably represented in a digitally coded format at a specific sampling rate or frequency such as 32 kHz, 48 kHz, 96 kHz, etc., as described above.

The first signal processor of the first hearing aid either filters the third monaural beam forming signal through the entire range, or delays the third monaural beam forming signal by the number of clock cycles of the clock signal of the first signal processor. And may include an all-pass filter circuit or algorithm configured to generate a predetermined time delay of the third monaural beam forming signal. In one embodiment, the first signal processor has a third monaural beamforming measured at 1 kHz, greater than 4 ms or 5 ms, and preferably less than 50 ms, such as between 5 ms and 20 ms. It is configured to delay the signal. The time delay may be generated by a separate hardware circuit or component of the first signal processor. The appropriate length of this time delay will be described in more detail below with reference to the accompanying drawings. As one of ordinary skill in the art will discuss further details below with reference to the accompanying drawings, the time delay provided between the bilateral beamforming signal and the third monaural beamforming signal is the first hybrid beamforming. You will understand that it plays a role in temporally uncorrelating these signal components of the signal.

The first microphone device is configured to generate first and second omnidirectional microphone signals as inputs to a first beamforming algorithm that forms a first monaural beamforming signal. It is preferable to have at least an omnidirectional microphone and a second omnidirectional microphone. Alternatively, or additionally, the first microphone device may include a directional microphone configured to generate a directional microphone signal as an input to the first beamforming algorithm. The third monaural beamforming signal is preferably based on at least the first and second omnidirectional microphone signals. Because, as described in more detail below, the omnidirectional characteristics allow the first signal processor to obtain the directivity of the third monaural beamforming signal, and thus the third polar pattern, in the first and second. This is because each head-related transfer function of the omnidirectional microphone signal and each filter function are used to allow a flexible method to match a specific target function.

One embodiment of the first second hearing aid can include first and second omnidirectional microphones and a third omnidirectional microphone or directional microphone. The first hearing aid has a predetermined anteroposterior spacing such that the respective sound inlets of the first and second omnidirectional microphones, or the first and second sound inlets of the directional microphones are larger than 5 mm or 10 mm. It may include a behind-the-ear housing portion that is placed. In general, a larger spacing or distance between the first and second sound inlets improves the directivity and directivity index (DI) of the first monaural beamforming signal, as well as the third monaural beamforming. Improves signal directivity and directivity index (DI). The relatively large spacing between the first and second sound inlets of the first and second omnidirectional microphones may be realized in certain embodiments of the first hearing aid, wherein the first hearing aid is: In addition to the housing portion behind the ear, it comprises a RIC earplug or similar in-ear housing portion that may include a small speaker or receiver for producing output sound. The latter housing portion is typically physically separated from the intraocular housing portion by a considerable distance. In one embodiment, the first omnidirectional microphone may be located in the housing portion behind the ear, the second omnidirectional microphone, and its sound inlet may be located in the intraearial housing portion. good. In another embodiment, the first and second omnidirectional microphones are located within the housing portion behind the ear, while the third omnidirectional or directional microphone is the ear. It is placed on the inner housing part. The microphone signal from the intra-ear housing portion may be transmitted via a suitable signal wire or signal line to the housing portion behind the ear, typically including a first signal processor and battery.

According to one embodiment of the binoral hearing aid system, the first signal processor of the first hearing aid further provides a first hybrid beamforming signal in which the level of the third monaural beamforming signal changes. It is configured to adjust the level of the third monaural beamforming signal before mixing with or adding to the first bilateral beamforming signal. This feature allows the first signal processor to dynamically adapt the level of the third monaural beamforming signal, including off-axis sound sources and auditory cues, to the particular acoustic environment of the hearing aid user. The first signal processor is, for example, further
Based on the first and second microphone signals of the first hearing aid, the signal-to-noise ratio of the input sound is estimated.
For example, as described in more detail below with reference to the accompanying drawings, the estimated signal pair by increasing the level of the third monaural beam forming signal as the signal-to-noise ratio of the input sound increases. It may be configured to automatically and dynamically adjust the level of the third monaural beam forming signal in the first hearing aid based on the noise ratio.

One of ordinary skill in the art will form the first bilateral beamforming signal by various fixed or adaptive beamforming algorithms known in the art, such as delayed sum beamforming algorithms or filter-and-sum beamforming algorithms. You will understand that you can.

According to one embodiment of the binaural hearing aid, the first signal processor uses a time delay summing mechanism based on the first monaural beamforming signal Zl and the second monaural beamforming signal Zr, and the first buy. It is configured to adaptively calculate the lateral beamforming signal, which calculation comprises minimizing the cost function C (α, β) below.

Here, the constraint is α + β = 1, E is the statistical expected value, ^* indicates the conjugate of the complex function, and λ is the Lagrange multiplier, as described in more detail below with reference to the attached drawings. Is.

The first signal processor is preferably configured to generate a third monaural beamforming signal ^pr (f, φ) according to the following equation, and the second signal processor of the second hearing aid is the second. It is configured to generate the corresponding second monaural beamforming signal ^pl (f, φ) of the second hearing aid.

Here, φ represents an angle with respect to the sound source, and φ = 0 is the target direction.

_Hfl (f, φ) represents the head related transfer function of the first microphone of the second hearing aid measured on an acoustic mannequin such as KEMAR or HATS.

_Hbl (f, φ) represents the head related transfer function of the second microphone of the second hearing aid measured on an acoustic mannequin such as KEMAR or HATS.

H _fr (f, φ) represents the head related transfer function of the first microphone of the first hearing aid measured on an acoustic mannequin such as KEMAR or HATS.

H _br (f, φ) represents the head related transfer function of the second microphone of the first hearing aid measured on an acoustic mannequin such as KEMAR or HATS.

F _f (f, b) represents the frequency response of the second hearing aid, the first discrete-time filter, such as the FIR filter.

F _bl (f, b) represents the frequency response of the second hearing aid to a second discrete-time filter, such as an FIR filter.

F _fr (f, b) represents the frequency response of a third hearing aid, such as an FIR filter, of a third discrete-time filter.

F _br (f, b) represents the frequency response of the first hearing aid to a second discrete-time filter, such as an FIR filter.

The frequency responses of the spatial filters F _fl (f, b), F _bl (f, b), F _fr (f, b) and F _br (f, b) are preferably the first and second hearing aids, respectively. It is calculated offline by an external, appropriately programmed computer such as a personal computer or smartphone.

With respect to the first polar pattern or directivity characteristic of the first monaural beamforming signal, the above-mentioned maximum sensitivity in the target direction is 1 kHz, or more preferably the maximum sensitivity at any test frequency between 500 Hz and 4 kHz. Using the angle notation according to FIGS. 4 and 5, which will be described later, it is assumed that the angle range is narrow around the target direction, such as an angle range of 340 to 20 degrees, or more preferably 350 to 10 degrees. The minimum sensitivity of the first polarity pattern is preferably in the angular range of, for example, about 150-210 degrees, more preferably 170-190 degrees, behind the user, using the angular notation according to FIGS. 4 and 5 below. Located inside. The difference between the maximum and minimum sensitivities of the first polarity pattern can be greater than 10 dB at 1 kHz-eg, at any test frequency between 500 Hz and 4 kHz.

Regarding the characteristics of the third polar pattern or the directivity of the third monaural beamforming signal, the difference between the maximum sensitivity and the minimum sensitivity of the third polar pattern is 1 kHz, or between 500 Hz and 4 kHz. It may be greater than 10 dB at any test frequency. The maximum sensitivity of the third polar pattern of the right ear, eg, the first hearing aid, is preferably within the angular range of about 60-160 degrees, using the angular notation according to FIGS. 4 and 5, the user or. It is on the same side of the right ear of the human model. Similarly, the maximum sensitivity of the polar pattern of the monaural beamforming signal of the left ear, eg, the second hearing aid, is preferably FIGS. 4 and 5, as described in more detail below with reference to the accompanying drawings. It is on the same side of the left ear of the user or mannequin, such as within an angle range of about 200-300 degrees, using the angle notation by.

The minimum sensitivity of the third polarity pattern of the third monaural beamforming signal may be located in or near the target direction or contralateral to the hearing aid in the right ear. The difference between the minimum and maximum sensitivities of the third polar pattern at any particular test frequency is, among other things, the frequency response of the spatial filter described above and the physical dimensions of the microphone device, eg, the spacing of the sound inlets. Depends on. According to one embodiment of the first hearing aid, the difference between the maximum sensitivity of the third polar pattern and the sensitivity in the target direction is 1 kHz, or 500 Hz, as discussed in more detail below with reference to the accompanying drawings. Greater than 6 dB at any test frequency between 4 kHz.

With respect to the second polar pattern or directivity characteristic of the first bilateral beamforming signal, the above-mentioned maximum sensitivity in the target direction is 1 kHz, or more preferably the maximum sensitivity at any test frequency between 500 Hz and 4 kHz. , Using the angle notation according to FIGS. 4 and 5, which will be described later, means that the angle range is narrow around the target direction, such as an angle range of 340 ° to 20 °, or more preferably 350 ° to 10 °. And.

Further, it is preferable that the first signal processor of the first hearing aid is configured to compensate for the hearing loss of the first hybrid beamforming signal. Hearing loss compensation includes well-known amplification techniques for the generation of electrical hearing loss compensation output signals aimed at restoring normal hearing to the hearing aid user, such as multi-channel dynamic range compression and / or noise reduction. But it may be. Each of the first and second hearing aids will convert the electrical hearing loss compensation output signal to the corresponding acoustic or sound pressure within the user's external auditory canal, or to a multichannel electrode signal for the cochlear implant electrode. Further configured output transducers may be provided.

Each of the first signal processor and the second signal processor may include a software programmable microprocessor such as a digital signal processor or a dedicated digital logic circuit, or any combination thereof. As used herein, terms such as "processor," "signal processor," and "controller" are either hardware, a combination of hardware and software, software, or software in process. It is intended to refer to a microprocessor or CPU-related device. For example, a "processor", "signal processor", "controller", "system", etc. may be a processor, an object, an executable file, an executable thread, and / or a process executed on a program. Not limited to. For illustration purposes, terms such as "processor," "signal processor," "controller," and "system" refer to both applications and hardware processors running on the processor. One or more "processors", "signal processors", "controllers", "systems", etc., or any combination thereof, resides within a process and / or execution thread and is one or more "processors". , "Signal Processor", "Controller", "System", etc., or any combination thereof, may be localized on one hardware processor, optionally in combination with other hardware circuits. And / or in combination with other hardware circuits, they may be distributed between two or more hardware processors. Also, the processor (or similar term) may be any component capable of performing signal processing, or any combination of components. For example, the signal processor may be an ASIC processor, an FPGA processor, a general purpose processor, a microprocessor, a circuit component, or an integrated circuit.

A second aspect of the invention is bilateral spatial filtering of input sound in a first hearing aid and a second ear hearing aid located in, or vice versa, the user's right and left ears, respectively. The present invention relates to a method of reducing the noise of the target sound signal generated by the target sound source located in the target direction.
This method is used in the first hearing aid.
A step of generating one or more microphone signals by the microphone device of the first hearing aid in response to the input sound.
A step of using one or more microphone signals to form a first monaural beamforming signal that exhibits a polar pattern with maximum sensitivity in the target direction.
A step of receiving a second monaural beamforming signal indicating a polar pattern having maximum sensitivity in the target direction from the left ear hearing aid via a wireless data communication interface.
A first buy showing a polar pattern with maximum sensitivity in the target direction and reduced sensitivity on each side of the left ear and the first hearing aid, based on the first and second monaural beamforming signals. It comprises a step of generating a lateral beamforming signal.

This method also
Based on the microphone signal of one or more microphone devices of the first hearing aid, it has the maximum sensitivity on the same side of the first hearing aid, the reduced sensitivity in the target direction, and the first hearing aid. A step of generating a third monaural beamforming signal showing a polar pattern with reduced sensitivity on the contralateral side,
Apply a time delay to the third monaural beamforming signal relative to the first bilateral beamforming signal to reduce the correlation between the first bilateral beamforming signal and the third monaural beamforming signal. Steps to do and
A step of synthesizing or mixing a first bilateral beamforming signal and a third monaural beamforming signal to form a first hybrid beamforming signal.
The first, second, and third polar patterns are determined or determined at 1 kHz when the left ear and the first hearing aid are attached to the acoustic mannequin.

A method of reducing noise in a target sound signal is before mixing with a first bilateral beamforming signal or to provide a first hybrid beamforming signal in which the level of the third monaural beamforming signal changes. It may be provided with a step of dynamically adjusting the level of the third monaural beamforming signal before the mound. One embodiment of the latter method further comprises
The step of estimating the signal-to-noise ratio of the input sound in the first microphone device based on the one or more microphone signals by the first signal processor and / or by the second signal processor. A step of estimating the signal-to-noise ratio of the input sound in the second microphone device based on one or more microphone signals.
For example, by increasing the level of the third monaural beamforming signal with increasing the signal-to-noise ratio of the input sound, the level of the third monaural beamforming signal is automatically set based on the estimated signal-to-noise ratio. It has steps to adjust dynamically.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 3 is a schematic diagram of a binoral or bilateral hearing aid system comprising a left ear hearing aid and a right ear hearing aid connected via a bidirectional radio data communication channel according to a first embodiment of the present invention. FIG. 3 shows a schematic block diagram of a left ear hearing aid in a binaural or binaural hearing aid system according to a first embodiment of the present invention. FIG. 3 shows a simplified signal flow chart for implementation of a binaural beamformer in the block-based frequency domain according to an embodiment of the present invention. It is a schematic diagram of an exemplary arrangement of a target signal source such as a desired speaker and an interference signal source arranged in spatially separated directions around the user's head. Shown is an exemplary target function for the polarity pattern of the third monaural beamforming or monitor ear signal of the left and right ear hearing aids at frequencies 1 kHz, 2 kHz, and 4 kHz. As a function of sound source direction, the magnitudes of the anterior and posterior microphones of the left ear hearing aid are shown experimentally measured on the KEMAR of their respective head related transfer functions (HRTFs). As a function of sound source direction, the corresponding magnitudes of the anterior and posterior microphones of the right ear hearing aid are shown experimentally measured on KEMAR of their respective head related transfer functions (HRTFs). The frequency response of the first and second FIR filters of the right ear hearing aid as determined by the experimental optimization process is shown. The frequency response of the first and second FIR filters of the right ear hearing aid as determined by the experimental optimization process is shown. For one embodiment of the monaural beamformer, the polar patterns experimentally measured on KEMAR of the third monaural beamforming signal or monitor ear signal of the left ear hearing aid at frequencies of 1 kHz, 2 kHz, and 4 kHz are shown. For one embodiment of the monaural beamformer, the polar patterns experimentally measured on KEMAR of the third monaural beamforming signal or monitor ear signal of the right ear hearing aid at frequencies of 1 kHz, 2 kHz, and 4 kHz are shown. For a preferred embodiment of the bilateral beamformer, the polar patterns experimentally measured on KEMAR of the bilateral beamforming signals of the left and right ear hearing aids at frequencies of 1 kHz, 2 kHz, and 4 kHz are shown. A typical autocorrelation function of speech in decibels as a function of time delay is shown.

In the following, various exemplary embodiments of the binaural hearing aid system will be described with reference to the accompanying drawings. Those skilled in the art will appreciate that the accompanying drawings are schematic and simplified for clarity and therefore merely show the details that are essential to the understanding of the invention and omit other details. You will understand that you are. Throughout, similar reference numbers refer to similar elements. Therefore, similar elements are not necessarily described in detail for each figure.

FIG. 1 schematically illustrates a binaural or bilateral hearing aid system 50 with a left ear hearing aid or device 10L and a right ear hearing aid or device 10R, each of the left ear hearing aid or device 10L and the right ear hearing aid or device 10R being the other. Equipped with a wireless communication interface for connecting to hearing aids. In this embodiment, the left and right ear hearing aids 10L and 10R are connected to each other via a bidirectional wireless data communication channel or link 12 that supports real-time streaming of digitized microphone signals. The unique ID may be associated with each of the left and right ear hearing aids 10L and 10R. Each of the illustrated wireless communication interfaces 34L, 34R of the Binoral Hearing Aid System 50 may be configured to operate in the 2.4 GHz Industrial Science and Medical Care (ISM) band or may comply with the Bluetooth LE standard. Alternatively, each of the illustrated wireless communication interfaces 34L, 34R may be based on near-field magnetic coupling, such as NMFI, including magnetic coil antennas 44L, 44R and operating in the frequency domain of 10-20 MHz.

The left hearing aid 10L and the right hearing aid 10R are of this hearing aid system, except for the unique ID described above, so that the following description of the features, components, and signal processing functions of the left hearing aid 10L also applies to the right hearing aid 10R. It may be substantially the same in some embodiments. The left hearing aid 10L may include a ZnO ₂ battery (not shown) or a rechargeable battery connected to power the hearing aid circuit 14L. The left hearing aid 10L preferably comprises a microphone device 16L with at least first and second omnidirectional microphones, as described in more detail below.

The left hearing aid 10L further comprises a signal processor 24L that may include a hearing loss processor. The signal processor 24L is also configured to perform monaural beamforming and bilateral beamforming on the microphone signal and contralateral microphone signal of the left hearing aid, as described in more detail below. The hearing loss processor is configured to compensate for the hearing loss of the user of the left hearing aid 10L. Preferably, the hearing loss processor 24L comprises a well-known dynamic range compression circuit or algorithm for compensating for the frequency-dependent loss of the user's dynamic range, often referred to in the art as recruitment. Therefore, the signal processor 24L generates a bilateral beamforming audio signal with additional hearing loss compensation and outputs it to a loudspeaker or receiver 32L. The loudspeaker or receiver 32L converts the electrical audio signal into a corresponding acoustic signal for transmission to the user's left ear canal.

Those skilled in the art will appreciate that each of the signal processors 24L, 24R may include a software programmable microprocessor such as a digital signal processor. The operation of each of the left and right ear hearing aids 10L and 10R can be controlled by an appropriate operating system running on a software programmable microprocessor. The operating system may, for example, calculate bilateral beam forming signals, calculate first and third monaural beam forming signals, calculate hearing loss compensation, and possibly other processors and related signal processing algorithms, wireless data communication. It may be configured to manage hearing aid hardware and software resources, including the interface 34L, specific memory resources, and the like. The operating system may schedule tasks for efficient use of hearing aid resources, and further accounting software for cost allocation, including power consumption, processor time, memory location, radio transmission, and other resources. It may be included. The operating system is such that the first monaural beam forming signal is transmitted to the right ear hearing aid 10R and the second monaural beam forming signal is received from the right ear hearing aid via the wireless data communication interface 34L and the communication channel 12. , The operation of the wireless data communication interface 34L may be controlled. The right ear hearing aid 10R has similar hardware and software components that function in the corresponding manner.

FIG. 2 is a schematic block diagram of a binaural or binaural hearing aid system 50, a left ear hearing aid or instrument 10L for placement in or within the user's left ear. The illustrated components of the left ear hearing aid 10L may be located within one or more hearing aid housing portions such as BTE, RIE, ITE, ITC, CIC, RIC and the like type hearing aid housings. The hearing aid 10L preferably comprises a microphone device comprising at least the first and second omnidirectional microphones 101a, 101b described above, which generate first and second microphone signals in response to input or collision sounds, respectively. It is equipped with 16L. The sound inlets or ports (not shown) of the first and second omnidirectional microphones 101a and 101b are preferably arranged at regular intervals in one housing portion of the hearing aid 10L. There is. The spacing between sound inlets or ports may be between 5 and 30 mm, depending on the dimensions and type of housing portion. This port spacing range allows the formation of a first monaural beamforming signal by applying sum and delay techniques to the first and second microphone signals. The hearing aid 10L preferably converts an analog microphone signal into a corresponding digital microphone signal at a certain resolution and sampling frequency prior to application to the first monaural beamformer 105 (Figure). Not shown). Those skilled in the art may implement the first monaural beamformer 105 as dedicated computing hardware for the signal processor 24L, or the programmable microprocessor or DSP described above, or the dedicated computing hardware and executable program instructions. It will be appreciated that it may be implemented by a set of appropriate executable program instructions executed on the signal processor 24L, such as any combination with.

The first monaural beamformer 105 is configured to generate a first monaural beamforming signal 120 based on the first and second microphone signals, the beamforming signal 120 is shown in FIGS. 4 and 5. As such, it shows the first polarity pattern with maximum sensitivity in the target direction, i.e. the direction or orientation of zero degrees. The maximum sensitivity in the target direction is reduced compared to the maximum sensitivity for the sound signal that the first polar pattern arrives from the latter half of the user's head, that is, the sound signal that arrives in the direction of about 180 degrees. Since it exhibits sensitivity, the first monaural beamforming signal 120 is well adapted as an input signal to the bilateral beamformer. The relative attenuation or suppression of sound arriving from the rear direction relative to the target direction may be greater than 6 dB or 10 dB when measured at 1 kHz.

The signal processor 24L right-hands the first monaural beam forming signal 120 via an RF or NFMI antenna 44L and a wireless data communication interface 34L using an appropriate dedicated or standardized communication protocol that supports real-time audio. That is, it is configured to transmit to the hearing aid 10R on the opposite side. Those skilled in the art will appreciate that the first monaural beamforming signal 120 is preferably encoded in a digital format, eg, a standardized digital audio format. The signal processor 24L is also configured to receive a second monaural beamforming signal 121 from the right hearing aid 10R via the wireless data communication interface 34L. The signal processor 24L uses the sum and delay bilateral beamformers 106 based on the first and second monaural beamforming signals 120 and 121 to generate the first bilateral beamforming signal 107. The bilateral beamforming signal 107 has the maximum sensitivity in the target direction and exhibits a second polar pattern with reduced sensitivity on the opposite side of each of the first and second hearing aids. The sum and delay bilateral beamformers 106 also adaptively provide bilateral beamforming signals 107 based on the first monaural beamforming signal 120 (Sl) and the second monaural beamforming signal 121 (Sr). It is configured to calculate.

Those skilled in the art will use the first and second microphone signals of the microphone device 16R to signal the right hearing aid 10R in such a way that the second monaural beamforming signal corresponds to the formation of the first monaural beamforming signal 120. You will understand that it is formed by the processor 24R. Similarly, the signal processor 24R of the right hearing aid 10R receives the first monaural beamforming signal 120 via the bidirectional wireless data communication channel or link 12, and the first and second monaural beamforming signals 120, 121. Is configured to generate a second bilateral beamforming signal (not shown). The second bilateral beamforming signal is a polar pattern corresponding to the bilateral beamforming signal 107, having maximum sensitivity in the target direction and reduced sensitivity on the opposite sides of the left and right hearing aids, respectively. Have.

Those skilled in the art have found that both the amplitude and phase of the left-ear and right-ear microphone signals are at different angles of the off-axis source, ie, the target direction (0 degrees), due to the head shadow effect. Understand that it is different for the sound source. The amplitudes of the left-ear microphone signal and the right-ear microphone signal are preferably equalized prior to the sum calculation in the delayed sum beamforming scheme. In this embodiment of the bilateral hearing aid system, it is generally assumed that the target sound source or speaker is located 0 degrees in front of the user or listener of the hearing aid system.

According to the bilateral beamformer 106 or one embodiment of the beamforming algorithm, the first monaural beamforming signal 120 (Sl) and the second monaural beamforming signal 121 (Sr) are directed in a target direction, eg, a target or a desired. Combined for the purpose of further emphasizing the sound signal from the speaker or speaker. An object of this embodiment of the bilateral beam former 106 is an off-axis interference that may include not only various types of household or industrial machines, but also one or more competing speakers, such as in well-known cocktail party situations. It is to suppress the noise source. The first and second monaural beamforming signals 120 and 121 satisfy the condition Sl = Sr for the reason of symmetry with respect to the sound signal arriving from the target direction in front of the listener, and the beamforming signal S is obtained. Generate.

The beamforming signal S should be minimized for sound signals arriving outside the target direction, such as sound signals arriving beside or behind the hearing aid user or listener. That is, the signal from the off-axis sound source should be suppressed. This purpose can be expressed by the following equation.

Here, rms represents the root mean square value of the signal. Therefore, in order to achieve the purpose, it is necessary to obtain the optimum value of α. This is equivalent to solving α and β in the following cost function C (α, β) in the frequency domain.

The constraint is α + β = 1, and E is the statistical expected value. ^* Indicates the conjugate of the complex function. Symbols Z _l and Z _r are signal representations in the frequency domain of S _l and _Thr , respectively, generated by an FFT or similar time-frequency domain transform.

The optimal solution is preferably obtained by minimizing the cost function as follows.

Gradient is taken by applying the probability steepest descent algorithm.

Solve Lagrange.

Therefore, the gradient is as follows.

The least squares mean (LMS) solution is:

Here, μ is the step size.

The normalized least squares (NLMS) algorithm can be written as:

The update is preferably executed when V ^* · V> 0. The default value of the step size μ may be set to a value of 0.0002 to 0.01, such as μ = 0.001. The step size determines the convergence speed.

FIG. 10 shows the respective polar patterns of the bilateral beamforming signal 107 measured at 1 kHz, 2 kHz and 4 kHz for the above embodiment of the bilateral beamformer 106. The polarity pattern of the bilateral beamforming signal 107 is obtained by measuring its sensitivity as a function of the azimuth angle of 0 to 360 degrees of the test sound source. The left and right hearing aids are properly placed on a KEMAR or similar acoustic mannequin that simulates the average acoustic properties of the human head and torso. The test source may generate a broadband test signal, such as a maximum length sequence (MLS) sound signal, and is reproduced in a given size, eg, 5 or 10 degree steps, at each azimuth angle from 0 to 360 degrees. To. The acoustic transfer function is derived from the bilateral beamforming signal 107 and the test signal. The power spectrum of the acoustic transfer function represents the amplitude response of the bilateral beamforming signal 107 at each azimuth. For adaptive beamformers and beamforming algorithms, the user's reality is to apply Schroeder's phase composite harmonics as the acoustic test sound signal in the diffuse sound field to avoid overestimating the sensitivity of the beamforming signal 107. It may be advantageous to simulate a typical acoustic environment. The amplitude spectral response may be estimated, for example, based on the harmonic amplitude between the reproduction of the test sound signal and the resulting bilateral beamforming signal 107.

FIG. 3 shows a simplified signal flow chart of the implementation of the calculations outlined above for the bilateral beamforming signal performed by the bilateral beamformer 106 in the block-based frequency domain. At step 340, the signal processor acquires or reads N time domain signal samples of the first monaural beamforming signal 120. N may be 16 to 96 samples. In step 342, the signal processor adds N samples of the first monaural beamforming signal 120 to the previous sample segment of the first monaural beamforming signal 120. At step 346, an appropriate analysis window of length M, such as a Hanning window, is applied to the attached sample. In step 348, the time domain sample to which the window is applied is transformed into the frequency domain by an FFT function or algorithm. The frequency domain signal Z _l on the left side is input to the α calculation step 349. At the same time, the signal processor applies the same processing to the second monaural beamforming signal 121 in steps 341, 343, 345, 347. As a result, the frequency domain signal _Zr on the left side, which is also input to the α calculation step 349, is provided. In step 349, V represents a beamforming signal segment in the frequency domain, and V ^* · V is the power spectrum of the segment V. The α calculation step 349 updates the value of α, and in step 350, under the above constraint α + β = 1, using the current values of the scaling coefficients α and β, the left and right frequency domain signals Z _l . , Z _r The bilateral beamforming signal segment V is calculated as a weighted sum. In step 352, the signal processor transforms the signal segment V back into the time domain. In step 354, the signal processor applies an appropriate compositing window to the time domain segment of the calculated signal V and then with a particular overlap, such as an overlap between 25% or 75%, after V. Signal segments are added. Finally, at the output of step 358, a new segment of bilateral beamforming signal 107 becomes available.

The second monaural beamformer 102 is a third monaural beamforming signal of the left ear hearing aid 10L based on the first and second microphone signals supplied by the front and rear microphones 101a and 101b of the microphone device 16L, respectively. It is configured to generate 122. The third monaural beamforming signal 122 has a third polarity pattern indicating a third polarity pattern having maximum sensitivity lateral to the first or left hearing aid 10L and reduced sensitivity in the target direction. .. The third polarity pattern also shows reduced sensitivity on the opposite side of the first hearing aid 10L, i.e., on the side of the second or right hearing aid 10R, compared to the maximum sensitivity on the side of the left hearing aid 10L. .. The relative attenuation or suppression of sound coming from the target direction and contralateral is that the third monaural beamforming signal 122 has an angular range around the side of the left hearing aid 10L, ie, the angular representation according to FIGS. 4 and 5. Means to focus on the sound source from an angle range of about 210-330 degrees. The target sound source 460, for example, a human speaker, is located in the 0 degree target direction in front of the hearing aid user 463.

From the side of the left hearing aid 10L to the target direction, and optionally over the entire range of 210-330 degrees, the sensitivity to incoming sound is KEMAR or similar acoustics that simulate the average acoustic characteristics of the human head and torso. It may be larger than 6 dB or 8 dB, and may be larger than, for example, 10 dB, measured at 1 kHz on a mannequin. The left hearing aid 10L is properly attached to or in the left ear of KEMAR and the right hearing aid 10R is appropriately attached to or in the right ear of KEMAR. Sound sensitivity from the side of the left hearing aid 10L, optionally over the entire range of 210-330 degrees, compared to the contralateral angle of 90 degrees, is greater than 6 dB or 8 dB as measured by KEMAR at 1 kHz. It may be large, for example, larger than 10 dB. Those skilled in the art may implement the second monaural beamformer 102 as dedicated computing hardware for the signal processor 24L, or the programmable microprocessor or DSP described above, or the dedicated computing hardware and executable program instructions. It will be appreciated that it may be implemented by the appropriate set of executable program instructions executed on the signal processor 24L, such as any combination with.

FIG. 9A shows a third monaural beamforming signal 122 generated at 1 kHz, 2 kHz and 4 kHz by the second monaural beamformer 102 of the left hearing aid 10L for the embodiments disclosed below for the second monaural beamformer. The polar patterns measured experimentally on KEMAR are shown. FIG. 9B shows the second monaural generated at 1 kHz, 2 kHz and 4 kHz by the second monaural beamformer (not shown) of the right hearing aid 10R for the embodiments disclosed below for the second monaural beamformer. The corresponding polarity patterns experimentally measured on KEMAR of the beamforming signal are shown. The polarity pattern is mirror-symmetrical around the anteroposterior axis (0-180 degrees), as expected.

As shown below, the third monaural beamforming signal 122 of the left hearing aid 10L is indicated by ^Pl (f, φ), and the second monaural beamforming signal of the right hearing aid 10R is ^Pr (f, φ). ). Each spatial filter is preferably calculated offline by a well-programmed computing device such as a personal computer.

Here, φ represents an angle with respect to the sound source, and φ = 0 is the target direction.

_Hfl (f, φ) is the head related transfer function of the first microphone 101a of the microphone device 16L of the left ear hearing aid, as schematically shown in FIG. 4, measured by an acoustic mannequin such as KEMAR or HATS. Represents.

_Hbl (f, φ) is the second microphone 101b of the left ear hearing aid microphone device 16L, measured with an acoustic mannequin such as KEMAR or HATS, as schematically shown in FIG. Represents a head-related transfer function.

H _fr (f, φ) is the head related transfer function of the first microphone 101c of the microphone device 16R of the right ear hearing aid, as schematically shown in FIG. 4, measured by an acoustic mannequin such as KEMAR or HATS. Represents.

_Hbr (f, φ) is the head related transfer of the second microphone 101d of the microphone configuration 16L of the right ear hearing aid, as schematically shown in FIG. 4, measured on an acoustic mannequin such as KEMAR or HATS. Represents a function.

F _f (f, b) represents the frequency response of a second or first discrete-time filter of the left ear hearing aid, such as an FIR filter.

F _bl (f, b) represents the frequency response of a second discrete-time filter of the left ear hearing aid, such as an FIR filter.

F _fr (f, b) represents the frequency response of the first discrete-time filter of the right ear hearing aid, such as the FIR filter.

F _br (f, b) represents the frequency response of the second discrete-time filter of the right ear hearing aid, such as the FIR filter.

FIG. 6 shows the head related transfer functions (HRTFs) on the KEMAR of the first and second microphones 101a and 101b of the left ear hearing aid 10L as functions of the sound source direction shown at the angle set in FIG. Represents the experimentally measured magnitudes of _{Hfl (f, φ) and Hbl (} f, φ). The solid line plot shows H _fl (f, φ) and the dashed line plot shows H _bl (f, φ). As schematically shown in FIG. 5, the first microphone 101a is a front microphone and the second microphone 101b is a rear microphone.

FIG. 7 shows the head related transfer functions (HRTFs) on the KEMAR of the first and second microphones 101c and 101d of the right ear hearing aid 10R as functions of the indicated sound source direction at the angle shown in FIG. Represents the corresponding magnitudes of H _fr (f, φ) and H _br (f, φ) measured experimentally. The solid line plot shows H _fr (f, φ) and the dashed line plot shows H _br (f, φ).

The optimal response function for the third monaural beamforming signal 122 (P ^l (f, φ)) of the left hearing aid 10L and the second monaural beamforming signal (P ^l (f, φ)) of the right hearing aid 10R is , Can be determined by an optimization process that minimizes the next cost function.

Here, a, b, c and d are the FIRs of the FIR filters F _f (f, b), F _bl (f, b), F _bl (f, b) and F _br (f, b) described above, respectively. Representing a filter coefficient, Target (f, θ) is an objective function.

Preferred objective functions are schematically shown in FIG. 5, i.e. target (f, θ) = 1 (30 <θ <330), 0 (otherwise).

In other words, the target function for the second monaural beamforming signal of the left and right hearing aids is designed to be maximally sensitive to sound arriving outside the 330-30 degree angular space around the target direction. Is or is intended for it. Also, the target function for the second monaural beamforming signal is intended to exhibit virtually zero sensitivity to sound arriving from a position inside an angular space of 330 to 30 degrees. This objective function provides bilateral beamforming signals 107 and third monaural beamforming for each hearing aid, subject to the finite amount of computational resources and practical and physical limitations of microphone placement in each of the left and right ear hearing aids. It seeks to maximize the spatial non-correlation with the signal 122 to the extent possible.

8A and 8B show the determined frequency responses of the first and second FIR filters F _fr (f, b) and F _br (f, b) of the second hearing aid using the optimization process described above, respectively. The plot 801 of FIG. 8A shows the size and the plot 803 of FIG. 8B shows the phase. The frequency responses of the corresponding FIR filters _{Ffl (f, b) and Frl (} f, b) of the left hearing aid are substantially identical and are therefore not shown for brevity. For those skilled in the art, the respective filter coefficients of the first and second FIR filters F _fr (f, b) and F _br (f, b) of the second hearing aid are preferably signals of the second hearing aid. You will understand that it is downloaded to the processor and stored in the appropriate non-volatile storage device or area (not shown) of the second hearing aid. This task may be performed during the manufacture of the second hearing aid or during the fitting of the second hearing aid. The first signal processor 24L preferably filters the first and second FIR filters, respectively, during power-up and initialization of the signal processor to enable the functionality of the second monaural beamformer 102. It is configured to read and use the coefficients. The second signal processor 24R of the right hearing aid 10R is operating in the corresponding manner.

As mentioned above, FIGS. 9A and 9B show the second monaural beamforming signal of the left and right hearing aids, the KEMAR of the side monitor channel, generated by the second monaural beamformer at 1 kHz, 2 kHz and 4 kHz. The polar patterns measured experimentally above are shown. Those skilled in the art will appreciate that the polarity pattern of FIG. 9A shows maximum sensitivity for all test frequencies on the side of the left ear hearing aid, eg, at an angle between about 210 degrees and 270 degrees, and comes from the target direction. It will be appreciated that it exhibits a relatively reduced sensitivity of about 8-10 dB to sound. However, such a reduction in sensitivity to sound coming from the target direction is inferior to the design goal of about zero sensitivity to sound coming from inside the target area between 330 and 30 degrees from the target direction. ing. This is due to the practical limitations discussed earlier.

The role of the third monaural beamforming signal 122 and the bilateral beamforming signal 107 in the formation of the hybrid beamforming signal 109 will be discussed here with reference to the schematic block diagram of FIG. 2 of the left ear hearing aid 10L. The signal processor of the left ear hearing aid, for example, by applying a time delay function, filter or block 103 to the third monaural beamforming signal 122, as opposed to the bilateral beamforming signal 107, the third monaural beamforming signal 122. Is configured to introduce a time delay. This time delay serves to temporally uncorrelate the third monaural beamforming signal 122 and the bilateral beamforming signal 107. FIG. 11 shows this uncorrelated property of the applied time delay and shows the autocorrelation function in dB of voice as a function of the time delay measured in milliseconds (ms). It is clear that the autocorrelation decreases with increasing time delay and the speech autocorrelation decreases by about 10 dB with respect to the time delay per 5 ms.

Those skilled in the art will appreciate that the time delay of the time delay function 103 may be constant at all frequencies of the audio bandwidth, eg, about 100 Hz to 10 kHz, or varies over a predetermined bandwidth. You will understand that it is okay. In either case, the time delay of the third monaural beamforming signal 122 measured at 1 kHz is preferably greater than 4 ms or 5 ms, or 10 ms. A time delay of the third monaural beamforming signal 122 measured at 1 kHz is preferred in order to avoid introducing any user perceptible echo effect, which is typically very disturbing and perceptually unpleasant. Is less than 50 ms, for example less than 30 ms. The time delay function 103 may include an all-pass filter indicating any of the above time delays at 1 kHz, but includes smaller or larger time delays at other frequencies within a predetermined bandwidth. obtain. An alternative embodiment of the time delay function 103 may impart a pure time delay to the monaural beam forming signal 122, which may be delayed by a certain number of clock cycles of the clock signal associated with the signal processor. This is especially simple with the digitally sampled version of the monaural beam forming signal 122. The output of the time delay function 103 thereby produces or provides a time delay replica or version 124 of the third monaural beam forming signal 122, the latter signal being delayed and amplified or attenuated in the second monaural. At the input of a gain function 104 that may be configured to amplify or attenuate the level of the time-delayed replica 124 of the third monaural beam forming signal 122 before the beam forming signal 126 is input to the signal mixer or signal synthesizer 108. Applies.

In certain embodiments, the signal processor has a level of third monaural beam forming signal 122, depending on, for example, the characteristics of the input sound, such as the estimated signal-to-noise ratio, and / or the presence of sound in the input sound. To provide a variable hybrid beam forming signal 109, adjust the level of the delayed replica or version 124 of the third monaural beam forming signal 122 before mixing with the bilateral beam forming signal 107 in the signal mixer 108. It may be configured in.

The signal mixer 108 forms or generates a hybrid beamforming signal 109, i.e., a beamforming signal or a directional signal including the signal component of the bilateral beamforming signal 107 and the signal component of the delayed second monaural beamforming signal 124. The delayed and amplified / attenuated second monaural beamforming signal 126 and the bilateral beamforming signal 107 are configured to be coupled, integrated or added together.

The signal processor may apply the hybrid beamforming signal 109 to the aforementioned conventional hearing loss function or module 110 of the left hearing aid 10L. The conventional hearing loss processor 110 is configured to compensate for the user's hearing loss in the left hearing aid 10L, to the aforementioned small loudspeaker or receiver 32L, or instead, multiple output electrodes in a cochlear implant type output stage. To provide a hearing loss compensation output signal. The conventional hearing loss processor 110 is an output or power amplifier for driving a small loudspeaker or receiver 32L, such as a class D amplifier, such as a digitally modulated pulse width modulator (PWM) or pulse density modulator (PDM). (Not shown) may be provided. The small loudspeaker or receiver 32L converts the electrical hearing loss compensation output signal into a corresponding acoustic signal that can be transmitted to the user's eardrum, for example, via a properly molded and sized earplug of the left hearing aid 10L. do.

Those skilled in the art will appreciate that the hybrid beamforming signal 109, which includes the signal component of the bilateral beamforming signal 107 and the signal component of the delayed second monaural beamforming signal 124, is a well-known leading sound effect also known as the "Haas effect". By utilizing, you will understand that it has some beneficial properties. The preceding sound effect has a sound source arrangement shown in FIG. 4, having a target sound source 460 arranged in the target direction and an interference / noise sound source 461 arranged in the user's left ear, i.e. at an angle of about 270 degrees. Or indicate that the setup will provide a single coherent hearing between the bilateral beam forming signal, i.e. the lead sound, and the delayed second monaural beam forming signal. The hybrid beamforming signal 109 can also provide the hearing aid user 465 with a reliable spatial cue for lateral movement of the target sound source 460. The hybrid beamforming signal 109 enhances the specific information carried by the target sound source 460 and is useful for hearing aid user situation recognition, such as room acoustics and recognition of interference / off-axis sound sources 461. The leading tone effect is used to generate the hybrid beamforming signal 109. This is due to the time delay introduced between the bilateral beamforming signal 107 and the third monaural beamforming signal 122, eg, a delay greater than 4 ms or 5 ms. This time delay helps reduce the coherence or correlation between the leading and delayed signal components of the hybrid beamforming signal and the second monaural beamforming signal. At the same time, this time delay reduces the delay suppression effect, i.e., the contribution of the delayed sound to the sound image transmitted to the hearing aid user becomes more effective.

Further, the polarity pattern of the third monaural beamforming signal 122 obtained as described above and as a result correlates between the bilateral beamforming signal 107 and the third monaural beamforming signal 122, that is, the monitor ear signal 122. It works to further reduce it. Based on this spatial filtering design, ie the monitor ear signal 122 plus the bilateral beamforming signal 107, the off-axis speaker / noise interferer 461 can be controlled as illustrated by the circular region or dot 462. Can be perceptually visualized within the head of the hearing aid user 465 in any way. In contrast, with the bilateral beamformer signal alone, the two competing sources 460,461 are centered on the user's head with the off-axis speaker 461 suppressed, as indicated by the circular region or dot 464. Draw with. The coupling characteristics of the bilateral beam forming signal 107 and the monitor ear signal 122, as produced by this binaural hearing aid system, provide a perceptually spatialized sound image for the off-axis sound source to facilitate sound source separation. This separation of sources improves hearing aid user's speech comprehension, listening comfort, and situational awareness in noisy sound environments such as cocktail party environments.

ここで、制約はα＋β＝１であり、Ｅは統計的期待値であり、 ^＊ は複素関数の共役を示し、λはラグランジュ乗数である、特徴１から８のいずれか一項に記載のバイノーラル補聴器システム。
（特徴１０）
以下の式に従って、前記第１の信号プロセッサは、前記第３のモノラルビームフォーミング信号ｐ ^ｒ （ｆ，φ）を生成するようにさらに構成され、前記第２の信号プロセッサは、前記第２の補聴器の対応する第２のモノラルビームフォーミング信号ｐ ^ｌ （ｆ，φ）を生成するように構成され、

ここで、φは前記音源に対する角度を表し、φ＝０は目標方向であり、
Ｈ _ｆｌ （ｆ，φ）は、ＫＥＭＡＲまたはＨＡＴＳのような音響人体模型上で測定された前記第２の補聴器の前記第１のマイクロフォンの頭部伝達関数を表し、
Ｈ _ｂｌ （ｆ，φ）は、ＫＥＭＡＲまたはＨＡＴＳのような音響人体模型上で測定された前記第２の補聴器の前記第２のマイクロフォンの頭部伝達関数を表し、
Ｈ _ｆｒ （ｆ，φ）は、ＫＥＭＡＲまたはＨＡＴＳなどの音響人体模型上で測定された前記第１の補聴器の前記第１のマイクロフォンの頭部伝達関数を表し、
Ｈ _ｂｒ （ｆ，φ）は、ＫＥＭＡＲまたはＨＡＴＳなどの音響人体模型上で測定された前記第１の補聴器の前記第２のマイクロフォンの頭部伝達関数を表し、
Ｆ _ｆｌ （ｆ，ｂ）は、前記第２の補聴器の、ＦＩＲフィルタのような第１の離散時間フィルタの周波数応答を表し、
Ｆ _ｂｌ （ｆ，ｂ）は、前記第２の補聴器の、ＦＩＲフィルタのような第２の離散時間フィルタの周波数応答を表し、
Ｆ _ｆｒ （ｆ，ｂ）は、前記第１の補聴器の、ＦＩＲフィルタのような第３の離散時間フィルタの周波数応答を表し、
Ｆ _ｂｒ （ｆ，ｂ）は、前記第１の補聴器の、ＦＩＲフィルタのような第２の離散時間フィルタの周波数応答を表す、特徴１から９のいずれか一項に記載のバイノーラル補聴器システム。
（特徴１１）
前記第３のモノラルビームフォーミング信号の前記第３の極性パターンの最大感度と最小感度との間の差は、１ｋＨｚにおいて１０ｄＢよりも大きい、特徴１から１０のいずれか一項に記載のバイノーラル補聴器システム。
（特徴１２）
前記第３のモノラルビームフォーミング信号の前記第３の極性パターンの最大感度と前記目標方向の感度との差は、１ｋＨｚにおいて６ｄＢよりも大きい、特徴１から１１のいずれか一項に記載のバイノーラル補聴器システム。
（特徴１３）
ユーザの右耳および左耳にそれぞれ、またはその中に、またはその逆に配置される第１の補聴器および第２の耳補聴器において、入力音のバイラテラル空間フィルタリングによって、目標方向に位置する目標音源によって生成される目標音信号のノイズを低減する方法であって、
前記方法は、前記第１の補聴器において、
記入力音に応答して前記第１の補聴器のマイクロフォン装置によって１つ又は複数のマイクロフォン信号を生成するステップと、
前記１つまたは複数のマイクロフォン信号を用いて、前記目標方向で最大感度を有する極性パターンを示す第１のモノラルビームフォーミング信号を形成するステップと、
前記目標方向で最大感度を有する極性パターンを示す第２のモノラルビームフォーミング信号を、前記左耳補聴器から無線データ通信インターフェースを介して受信するステップと、
前記第１および第２のモノラルビームフォーミング信号に基づいて、前記目標方向で最大感度を有し、前記左耳および第１の補聴器のそれぞれの側方で低減された感度を有する極性パターンを示す第１のバイラテラルビームフォーミング信号を生成するステップと、
前記第１の補聴器の前記マイクロフォン装置の前記１つ又は複数のマイクロフォン信号に基づいて、前記第１の補聴器の同側で最大感度を有し、前記目標方向で低減された感度を有し、かつ前記第１の補聴器の対側で低減された感度を有する極性パターンを示す第３のモノラルビームフォーミング信号を生成するステップと、
前記第１のバイラテラルビームフォーミング信号と前記第３のモノラルビームフォーミング信号との間の相関を低減するために、前記第１のバイラテラルビームフォーミング信号に対して前記第３のモノラルビームフォーミング信号に時間遅延を適用するステップと、
第１のハイブリッドビームフォーミング信号を形成するために、前記第１のバイラテラルビームフォーミング信号及び前記第３のモノラルビームフォーミング信号を合成又は混合するステップと、を備え、
前記第１、第２、および第３の極性パターンは、前記左耳および第１の補聴器が音響人体模型に取り付けられているときに、１ｋＨｚで決定されるか、または決定されている、方法。
（特徴１４）
前記第３のモノラルビームフォーミング信号のレベルが変化する前記第１のハイブリットビームフォーミング信号を提供するために、前記第１のバイラテラルビームフォーミング信号と混合する前、又は、追加する前に、前記第３のモノラルビームフォーミング信号のレベルを動的に調整するステップをさらに備える、特徴１３に記載の目標音信号のノイズを低減する方法。
（特徴１５）
第１の信号プロセッサによって、その前記１つ又は複数のマイクロフォン信号に基づいて前記第１のマイクロフォン装置における前記入力音の信号対ノイズ比を推定するステップと、および／または、
前記第２の信号プロセッサによって、その前記１つ又は複数のマイクロフォン信号に基づいて前記第２のマイクロフォン装置における前記入力音の信号対ノイズ比を推定するステップと、
例えば、前記入力音の信号対ノイズ比の増加と共に前記第３のモノラルビームフォーミング信号の前記レベルを増加させることによって、前記推定された信号対ノイズ比に基づいて前記第３のモノラルビームフォーミング信号の前記レベルを自動的かつ動的に調整ステップと、をさらに備える、特徴１４に記載の目標音信号のノイズを低減する方法。 Further, the polarity pattern of the third monaural beamforming signal 122 obtained as described above and as a result correlates between the bilateral beamforming signal 107 and the third monaural beamforming signal 122, that is, the monitor ear signal 122. It works to further reduce it. Based on this spatial filtering design, ie the monitor ear signal 122 plus the bilateral beamforming signal 107, the off-axis speaker / noise interferer 461 can be controlled as illustrated by the circular region or dot 462. Can be perceptually visualized within the head of the hearing aid user 465 in any way. In contrast, with the bilateral beamformer signal alone, the two competing sources 460,461 are centered on the user's head with the off-axis speaker 461 suppressed, as indicated by the circular region or dot 464. Draw with. The coupling characteristics of the bilateral beam forming signal 107 and the monitor ear signal 122, as produced by this binaural hearing aid system, provide a perceptually spatialized sound image for the off-axis sound source to facilitate sound source separation. This separation of sources improves hearing aid user's speech comprehension, listening comfort, and situational awareness in noisy sound environments such as cocktail party environments.
The features of the disclosed techniques are listed herein.
(Feature 1)
Binaural hearing aid system,
A first hearing aid for placement in or within the user's left or right ear, which wirelessly transmits a microphone signal over a first microphone device, a first signal processor, and a data communication channel. And the first hearing aid comprising a first data communication interface configured to receive.
A second hearing aid for placement in or in the opposite ear of the user, the microphone signal via the second microphone device, the second signal processor, and the data communication channel. A second hearing aid comprising a second data communication interface configured to transmit and receive wirelessly.
The first signal processor is
Based on one or more microphone signals supplied by the first microphone device in response to an input sound, a first monaural beamforming signal showing a first polar pattern with maximum sensitivity in the target direction is generated. ,
The first monaural beamforming signal is transmitted to the second and contralateral hearing aids via the first wireless communication interface.
A second monaural beamforming signal is received from the second hearing aid via the first wireless data communication interface.
A second polar pattern with maximum sensitivity in the target direction and reduced sensitivity on the ipsilateral sides of the user's left and right ears, based on the first and second monaural beamforming signals. Generates a first bilateral beamforming signal indicating
Based on the one or more microphone signals, it has maximum sensitivity on the same side of the first hearing aid, reduced sensitivity in the target direction, and reduced on the opposite side of the first hearing aid. Generates a third monaural beamforming signal indicating a third polarity pattern with the same sensitivity.
In order to reduce the correlation between the first bilateral beamforming signal and the third monaural beamforming signal, the third monaural beamforming signal is added to the first bilateral beamforming signal. Delay the time,
The first bilateral beamforming signal and the time-delayed third monaural beamforming signal are configured to be coupled or mixed to form a first hybrid beamforming signal.
The first, second and third polar patterns are binaural measured at 1 kHz using the first and second hearing aids attached to the right and left ears of the acoustic human model, respectively. Hearing aid system.
(Feature 2)
The first signal processor of the first hearing aid either exhaustively filters the third monaural beam forming signal to generate a predetermined time delay of the third monaural beam forming signal. The binaural hearing aid system according to feature 1, wherein the third monaural beam forming signal is configured to be delayed by the number of clock cycles of the clock signal of the first signal processor.
(Feature 3)
The first signal processor of the first hearing aid is greater than 4 ms or 5 ms measured at 1 kHz, preferably less than 50 ms, such as between 5 ms and 20 ms, said third monaural beam. The binaural hearing aid system according to any one of features 1 to 2, configured to provide a time delay in the forming signal.
(Feature 4)
The first microphone device of the first hearing aid is at least
A first omnidirectional microphone and a first omnidirectional microphone configured to generate first and second omnidirectional microphone signals as inputs to the first beamforming algorithm forming the first monaural beamforming signal. 2 omnidirectional microphones, or
5. The description of any of features 1 to 3, comprising a directional microphone configured to generate a directional microphone signal as an input to the first beamforming algorithm that forms the first monaural beamforming signal. Binoral hearing aid system.
(Feature 5)
In the first hearing aid, the sound inlets of the first and second omnidirectional microphones or the first and second sound inlets of the directional microphones are arranged at predetermined front-rear intervals. The binaural hearing aid system according to feature 4, comprising a behind-the-ear housing portion.
(Feature 6)
The first hearing aid further comprises a RIC plug or an in-ear housing portion.
The binaural hearing aid system according to feature 5, wherein the RIC plug or the intraocular housing portion comprises a third microphone, such as a directional microphone or an omnidirectional microphone.
(Feature 7)
The signal processor of the first hearing aid further
The third monaural before mixing with or adding to the first binaural beamforming signal to provide the hybrid beamforming signal in which the level of the third monaural beamforming signal changes. The binaural hearing aid system according to any one of features 1 to 6, configured to adjust the level of the beamforming signal.
(Feature 8)
The first signal processor further
Based on the first and second microphone signals of the first hearing aid, the signal-to-noise ratio of the input sound is estimated.
For example, in the first hearing aid, based on the estimated signal-to-noise ratio by increasing the level of the third monaural beam forming signal as the signal-to-noise ratio of the input sound increases. The binoural hearing aid system according to any one of features 1 to 7, configured to automatically and dynamically adjust the level of the third monaural beam forming signal.
(Feature 9)
The first signal processor of the first hearing aid further uses a time delay summing mechanism based on the first monaural beamforming signal Zl and the second monaural beamforming signal Zr. It is configured to adaptively calculate the bilateral beamforming signal of
The calculation involves minimizing the cost function C (α, β) below.

Here, the constraint is α + β = 1, E is the statistical expected value, ^* indicates the conjugate of the complex function, and λ is the Lagrange multiplier. system.
(Feature 10)
According to the following equation, the first signal processor is further configured to generate the third monaural beamforming signal ^pr (f, φ), and the second signal processor is the second hearing aid. It is configured to generate the corresponding second monaural beamforming signal ^pl (f, φ).

Here, φ represents the angle with respect to the sound source, φ = 0 is the target direction, and
Hfl (f, φ) represents the head related transfer function of the first microphone of the second hearing aid as measured on an acoustic mannequin such as KEMAR or HATS _.
Hbl (f, φ) represents the head related transfer function of the second microphone of the second hearing aid as measured on an acoustic mannequin such as KEMAR or HATS _.
H _fr (f, φ) represents the head related transfer function of the first microphone of the first hearing aid measured on an acoustic mannequin such as KEMAR or HATS.
H _br (f, φ) represents the head related transfer function of the second microphone of the first hearing aid measured on an acoustic mannequin such as KEMAR or HATS.
F _f (f, b) represents the frequency response of the first discrete-time filter, such as the FIR filter, of the second hearing aid.
F _bl (f, b) represents the frequency response of the second hearing aid to a second discrete-time filter, such as an FIR filter.
F _fr (f, b) represents the frequency response of the first hearing aid to a third discrete-time filter, such as an FIR filter.
F _br (f, b) is the binaural hearing aid system according to any one of features 1 to 9, wherein the F br (f, b) represents the frequency response of a second discrete-time filter, such as an FIR filter, of the first hearing aid.
(Feature 11)
The binaural hearing aid system according to any one of features 1 to 10, wherein the difference between the maximum sensitivity and the minimum sensitivity of the third polar pattern of the third monaural beamforming signal is greater than 10 dB at 1 kHz. ..
(Feature 12)
The binaural hearing aid according to any one of features 1 to 11, wherein the difference between the maximum sensitivity of the third polar pattern of the third monaural beamforming signal and the sensitivity in the target direction is larger than 6 dB at 1 kHz. system.
(Feature 13)
A target sound source located in the target direction by bilateral spatial filtering of the input sound in a first hearing aid and a second ear hearing aid placed in, or vice versa, the user's right and left ears, respectively. Is a method of reducing the noise of the target sound signal generated by
The method is performed in the first hearing aid.
A step of generating one or more microphone signals by the microphone device of the first hearing aid in response to the input sound.
A step of using the one or more microphone signals to form a first monaural beamforming signal showing a polar pattern with maximum sensitivity in the target direction.
A step of receiving a second monaural beamforming signal indicating a polar pattern having maximum sensitivity in the target direction from the left ear hearing aid via a wireless data communication interface.
Based on the first and second monaural beamforming signals, a first indicating a polar pattern having maximum sensitivity in the target direction and reduced sensitivity on each side of the left ear and the first hearing aid. Steps to generate a bilateral beamforming signal of 1 and
Based on the one or more microphone signals of the microphone device of the first hearing aid, it has maximum sensitivity on the same side of the first hearing aid, has reduced sensitivity in the target direction, and has A step of generating a third monaural beamforming signal showing a polar pattern with reduced sensitivity on the contralateral side of the first hearing aid.
In order to reduce the correlation between the first bilateral beamforming signal and the third monaural beamforming signal, the third monaural beamforming signal is used as opposed to the first bilateral beamforming signal. Steps to apply the time delay and
A step of synthesizing or mixing the first bilateral beamforming signal and the third monaural beamforming signal to form the first hybrid beamforming signal.
The method in which the first, second, and third polar patterns are determined or determined at 1 kHz when the left ear and the first hearing aid are attached to an acoustic mannequin.
(Feature 14)
The first, before mixing with or adding to the first bilateral beamforming signal, to provide the first hybrid beamforming signal in which the level of the third monaural beamforming signal changes. 3. The method of reducing noise in a target sound signal according to feature 13, further comprising a step of dynamically adjusting the level of the monaural beamforming signal of 3.
(Feature 15)
A step of estimating the signal-to-noise ratio of the input sound in the first microphone device by the first signal processor based on the one or more microphone signals, and / or.
A step of estimating the signal-to-noise ratio of the input sound in the second microphone device by the second signal processor based on the one or more microphone signals.
For example, by increasing the level of the third monaural beam forming signal with an increase in the signal-to-noise ratio of the input sound, the third monaural beam forming signal is based on the estimated signal-to-noise ratio. The method for reducing noise in a target sound signal according to feature 14, further comprising the step of automatically and dynamically adjusting the level.

Claims (15)

Binaural hearing aid system,
A first hearing aid for placement in or within the user's left or right ear, which wirelessly transmits a microphone signal over a first microphone device, a first signal processor, and a data communication channel. And the first hearing aid comprising a first data communication interface configured to receive.
A second hearing aid for placement in or in the opposite ear of the user, the microphone signal via the second microphone device, the second signal processor, and the data communication channel. A second hearing aid comprising a second data communication interface configured to transmit and receive wirelessly.
The first signal processor is
Based on one or more microphone signals supplied by the first microphone device in response to an input sound, a first monaural beamforming signal showing a first polar pattern with maximum sensitivity in the target direction is generated. ,
The first monaural beamforming signal is transmitted to the second and contralateral hearing aids via the first wireless communication interface.
A second monaural beamforming signal is received from the second hearing aid via the first wireless data communication interface.
A second polar pattern with maximum sensitivity in the target direction and reduced sensitivity on the ipsilateral sides of the user's left and right ears, based on the first and second monaural beamforming signals. Generates a first bilateral beamforming signal indicating
Based on the one or more microphone signals, it has maximum sensitivity on the same side of the first hearing aid, reduced sensitivity in the target direction, and reduced on the opposite side of the first hearing aid. Generates a third monaural beamforming signal indicating a third polarity pattern with the same sensitivity.
In order to reduce the correlation between the first bilateral beamforming signal and the third monaural beamforming signal, the third monaural beamforming signal is added to the first bilateral beamforming signal. Delay the time,
The first bilateral beamforming signal and the time-delayed third monaural beamforming signal are configured to be coupled or mixed to form a first hybrid beamforming signal.
The first, second and third polar patterns are binaural measured at 1 kHz using the first and second hearing aids attached to the right and left ears of the acoustic human model, respectively. Hearing aid system. The first signal processor of the first hearing aid either exhaustively filters the third monaural beam forming signal to generate a predetermined time delay of the third monaural beam forming signal. The binaural hearing aid system according to claim 1, wherein the third monaural beam forming signal is configured to be delayed by the number of clock cycles of the clock signal of the first signal processor. The first signal processor of the first hearing aid is greater than 4 ms or 5 ms measured at 1 kHz, preferably less than 50 ms, such as between 5 ms and 20 ms, said third monaural beam. The binaural hearing aid system of any one of claims 1 and 2, configured to provide a time delay in the forming signal. The first microphone device of the first hearing aid is at least
A first omnidirectional microphone and a first omnidirectional microphone configured to generate first and second omnidirectional microphone signals as inputs to the first beamforming algorithm forming the first monaural beamforming signal. 2 omnidirectional microphones, or
The invention according to any one of claims 1 to 3, further comprising a directional microphone configured to generate a directional microphone signal as an input of the first beamforming algorithm that forms the first monaural beamforming signal. Binaural hearing aid system. In the first hearing aid, the sound inlets of the first and second omnidirectional microphones or the first and second sound inlets of the directional microphones are arranged at predetermined front-rear intervals. The binaural hearing aid system of claim 4, comprising a behind-the-ear housing portion. The first hearing aid further comprises a RIC plug or an in-ear housing portion.
The binaural hearing aid system of claim 5, wherein the RIC plug or intra-ear housing portion comprises a third microphone, such as a directional microphone or an omnidirectional microphone. The signal processor of the first hearing aid further
The third monaural before mixing with or adding to the first binaural beamforming signal to provide the hybrid beamforming signal in which the level of the third monaural beamforming signal changes. The binaural hearing aid system according to any one of claims 1 to 6, which is configured to adjust the level of a beamforming signal. The first signal processor further
Based on the first and second microphone signals of the first hearing aid, the signal-to-noise ratio of the input sound is estimated.
For example, in the first hearing aid, based on the estimated signal-to-noise ratio by increasing the level of the third monaural beam forming signal as the signal-to-noise ratio of the input sound increases. The binoural hearing aid system according to any one of claims 1 to 7, which is configured to automatically and dynamically adjust the level of the third monaural beam forming signal. The first signal processor of the first hearing aid further uses a time delay summing mechanism based on the first monaural beamforming signal Zl and the second monaural beamforming signal Zr. It is configured to adaptively calculate the bilateral beamforming signal of
The calculation involves minimizing the cost function C (α, β) below.

Here, the binoral according to any one of claims 1 to 8, wherein the constraint is α + β = 1, E is the statistical expected value, ^* indicates the conjugate of the complex function, and λ is the Lagrange multiplier. Hearing aid system. According to the following equation, the first signal processor is further configured to generate the third monaural beamforming signal ^pr (f, φ), and the second signal processor is the second hearing aid. It is configured to generate the corresponding second monaural beamforming signal ^pl (f, φ).

Here, φ represents the angle with respect to the sound source, φ = 0 is the target direction, and
_Hfl (f, φ) represents the head related transfer function of the first microphone of the second hearing aid as measured on an acoustic mannequin such as KEMAR or HATS.
_Hbl (f, φ) represents the head related transfer function of the second microphone of the second hearing aid as measured on an acoustic mannequin such as KEMAR or HATS.
H _fr (f, φ) represents the head related transfer function of the first microphone of the first hearing aid measured on an acoustic mannequin such as KEMAR or HATS.
H _br (f, φ) represents the head related transfer function of the second microphone of the first hearing aid measured on an acoustic mannequin such as KEMAR or HATS.
F _f (f, b) represents the frequency response of the first discrete-time filter, such as the FIR filter, of the second hearing aid.
F _bl (f, b) represents the frequency response of the second hearing aid to a second discrete-time filter, such as an FIR filter.
F _fr (f, b) represents the frequency response of the first hearing aid to a third discrete-time filter, such as an FIR filter.
The binaural hearing aid system according to any one of claims 1 to 9, wherein F _br (f, b) represents the frequency response of a second discrete-time filter such as an FIR filter of the first hearing aid. The binaural hearing aid according to any one of claims 1 to 10, wherein the difference between the maximum sensitivity and the minimum sensitivity of the third polar pattern of the third monaural beamforming signal is larger than 10 dB at 1 kHz. system. The binaural according to any one of claims 1 to 11, wherein the difference between the maximum sensitivity of the third polarity pattern of the third monaural beamforming signal and the sensitivity in the target direction is larger than 6 dB at 1 kHz. Hearing aid system. A target sound source located in the target direction by bilateral spatial filtering of the input sound in a first hearing aid and a second ear hearing aid placed in, or vice versa, the user's right and left ears, respectively. Is a method of reducing the noise of the target sound signal generated by
The method is performed in the first hearing aid.
A step of generating one or more microphone signals by the microphone device of the first hearing aid in response to the input sound.
A step of using the one or more microphone signals to form a first monaural beamforming signal showing a polar pattern with maximum sensitivity in the target direction.
A step of receiving a second monaural beamforming signal indicating a polar pattern having maximum sensitivity in the target direction from the left ear hearing aid via a wireless data communication interface.
Based on the first and second monaural beamforming signals, a first indicating a polar pattern having maximum sensitivity in the target direction and reduced sensitivity on each side of the left ear and the first hearing aid. Steps to generate a bilateral beamforming signal of 1 and
Based on the one or more microphone signals of the microphone device of the first hearing aid, it has maximum sensitivity on the same side of the first hearing aid, has reduced sensitivity in the target direction, and has A step of generating a third monaural beamforming signal showing a polar pattern with reduced sensitivity on the contralateral side of the first hearing aid.
In order to reduce the correlation between the first bilateral beamforming signal and the third monaural beamforming signal, the third monaural beamforming signal is used as opposed to the first bilateral beamforming signal. Steps to apply the time delay and
A step of synthesizing or mixing the first bilateral beamforming signal and the third monaural beamforming signal to form the first hybrid beamforming signal.
The method in which the first, second, and third polar patterns are determined or determined at 1 kHz when the left ear and the first hearing aid are attached to an acoustic mannequin. The first, before mixing with or adding to the first bilateral beamforming signal, to provide the first hybrid beamforming signal in which the level of the third monaural beamforming signal changes. 3. The method of reducing noise in a target sound signal according to claim 13, further comprising a step of dynamically adjusting the level of the monaural beamforming signal of 3. A step of estimating the signal-to-noise ratio of the input sound in the first microphone device by the first signal processor based on the one or more microphone signals, and / or.
A step of estimating the signal-to-noise ratio of the input sound in the second microphone device by the second signal processor based on the one or more microphone signals.
For example, by increasing the level of the third monaural beam forming signal with an increase in the signal-to-noise ratio of the input sound, the third monaural beam forming signal is based on the estimated signal-to-noise ratio. The method of reducing noise in a target sound signal according to claim 14, further comprising the step of automatically and dynamically adjusting the level.

Images