Patent Application
20240298122
The present disclosure relates to hearing devices, e.g. hearing aids, in particular to such devices configured to have a low delay in the processing of audio signals.
In an aspect of the present application, a hearing aid configured to be worn by a user is provided. The hearing aid comprises
The at least one encoder may be configured to convert a first number of samples from said at least one stream of samples of the electric input signal in the first domain to a second number of samples in said at least one stream of samples of the electric input signal in the second domain. The decoder may be configured to convert said second number of samples from said stream of samples of the processed signal in the second domain to said first number of samples in said stream of samples of the electric input signal in the first domain. The second number of samples may be larger than the first number of samples. The at least one encoder may be trained (e.g. optimized). At least a part of said processing unit providing said compensation for the user's hearing impairment may be implemented as a trained neural network.
Thereby an improved hearing aid may be provided.
The encoder(s) and decoder are configured to convert said signals from the first to the second domain and from the second to the first domain, respectively, in batches of N1->N2 samples and N2->N1 samples, respectively, N1 and N2 being the first and second number of samples, respectively.
The encoder/decoder (e.g. parameters thereof) may be trained (e.g. optimized). The processing unit may be implemented as a trained neural network. The encoder (or encoder/decoder) and the neural network implementing the processing unit (or at least the part that compensates for the user's hearing impairment) may be jointly trained (in a common training procedure, e.g. with a single cost function). The trained encoder/decoder framework may learn information about frequency content, but the encoded channels are not necessarily specifically assigned to a particular frequency band, as the encoded “basis functions” as well may contain information across frequency and time, such as e.g. modulation.
The processing unit is configured to run one or more processing algorithms to improve the electric input signal in the second domain. The one or more processing algorithms may comprise a hearing loss compensation algorithm, a noise reduction algorithm (e.g. including a beamformer, and possibly a postfilter), a feedback control algorithm, etc., or a combination thereof.
The term ‘neural network’ or ‘artificial neural network’ may cover any type of artificial neural network, e.g. feed forward, recurrent, long/short term memory, gated recurrent unit (GRU), convolutional, etc.
The decoder may e.g. form part of the processing unit.
The encoder may e.g. implement a Fourier transform with a zero-padded input.
The second number (N2) of samples may be more than twice as large as the first number (N1) of samples. The second number (N2) of samples may be more than 5 times as large as the first number (N1) of samples. The second number (N2) of samples may be more than 10 times as large as the first number (N1) of samples.
The first domain may be the time domain.
Typically, when applying a Fourier transform, it corresponds to multiplying the N input samples by an N×N DFT matrix, i.e. X=Wx, where W=N×N, and x=N×1 and hence X=N×1. The “basis functions” related to the DFT matrix are illustrated in the Wikipedia link on the topic of ‘DFT matrix’ related to ‘depicting’ the DFT as a matrix multiplication: link: https://en.wikipedia.org/wiki/DFT_matrix (accessed on 30 May 2022).
In the case, where the size of the DFT matrix is larger than the N input samples, the input samples can be zero-padded.
A transform according to the present disclosure may be different from a Fourier transform in that the transformation matrix G according to the present disclosure is an N2×N1 matrix, where N2>N1, such that the transformed signal is S=Gs, where G=N2×N1, s=N1×1 and S=N2×1, where s is the original (e.g. time domain) signal and G is the transform (related to encoding). Thereby the inverse transformation matrix G−1 (related to decoding) may be written as a N1×N2 matrix, such that the inversely transformed signal is s=G−1S.
In the Fourier transform, each basis function contains a certain frequency. A Fourier transform may be seen as a special case of basis functions, where each basis function is a complex sine wave. By correlating each sine wave with the input signal, it is possible to find the frequencies contained in the input signal.
In a same way, each basis function according to the present disclosure may be “correlated with the input signal”, and in a similar way we can determine how well each basis function “correlates” with the input signal.
The at least one input unit may comprise an input transducer for converting the sound to the stream of samples of the electric input signal representing the sound in the first domain. The input transducer may comprise an analogue to digital converter to digitize an analogue electric input signal to a stream of audio samples. The input transducer may comprise a microphone (e.g. a ‘normal’ microphone configured to convert vibrations in air to an electric signal).
The encoder and/or the decoder may be implemented as a neural network, or as respective neural networks, or respective parts of a neural network. The encoder and/or the decoder may (each) be implemented as a feed forward neural network.
The at least one encoder and the processing unit may be configured to be optimized jointly in order to process the at least one electric input signal optimally under a low-latency constraint. The processing unit may comprise (or be constituted by) a neural network. The encoder may convert the first number (N1) of samples in the first domain to the second number (N2) of samples in the second domain. The second number (N2) of samples in the second domain may constitute at least a part of an input vector to the neural network (of the processing unit). The neural network (of the processing unit) may provide an output vector comprising the second number (N2) of samples in the second domain. The decoder may convert the second number (N2) of samples in the second domain to the first number (N1) of samples in the first domain.
The at least one encoder, the processing unit and the decoder may be configured to be optimized jointly in order to process the at least one electric input signal optimally under a low-latency constraint. The low-latency constraint may e.g. be implemented via a loss function in an optimization criterion, such that the error is minimized when the waveform of the output sound is “time aligned” with the waveform of the desired output sound.
An encoder and a decoder having been jointly optimized with the processing unit of the hearing aid under a low-latency constraint is termed a low-latency encoder and a low-latency decoder, respectively.
The low-latency constraint may e.g. be related to (a restriction to the) the processing time through the hearing device. The low-latency constraint may e.g. be related to the processing time through the encoder, the processing device and the decoder. The larger input frame, the higher latency through the hearing device. Thus, a constraint on the input frame size will enable a shorter latency through the hearing device.
Typically, when input frames are short (comprising relatively few audio samples), a filter bank will only obtain a limited frequency resolution. An advantage of the present invention is that by mapping short input frames into a high-dimensional space of basis-functions, allows a high-resolution modification of frequencies, e.g. according to the prescription obtained from an audiogram (and perhaps additional inputs), to be achieved.
The hearing aid (according to the present disclosure comprising an encoder/decoder combination) may be configured to have a maximum delay of 1 ms, such as 5 ms or such as 10 ms.
Parameters that participate in the (e.g. joint) optimization (training) may for the neural network include one or more of the weight-, bias-, and non-linear function-parameters of the neural network. Parameters that participate in the optimization during training may for the encoder and/or decoder include one or more of the first and second number of samples.
The at least one encoder/decoder combination may e.g. be configured to implement a linear transformations (such as a matrix multiplication).
The at least one encoder/decoder combination may e.g. contain one or more non-linear transformations (e.g. a neural network).
At least a part of the (functionality of the) processing unit may be implemented as a recurrent neural network (e.g. a GRU).
Parameters of the at least one encoder, the processing unit, and optionally the decoder may be trained in order to minimize a cost function given by the difference to a hearing device comprising linear filter banks instead of said at least one encoder and said decoder. The at least one encoder, the processing unit, and optionally the decoder may be trained together to provide optimized parameters of separate neural networks implementing the at least one encoder, the processing unit, and the decoder.
The hearing aid may comprise an output unit for providing stimuli perceivable as sound to the user based on the stream of samples of the processed signal in the first domain.
The hearing aid may comprise
The earpiece and the separate audio processing device may be configured to allow an exchange of audio signals or parameters derived therefrom between each other (e.g. via a wired or wireless link).
The separate audio processing device may be portable, e.g. wearable.
The earpiece and the separate audio processing device may comprise respective transceivers allowing the establishment of a wireless communication link between them, e.g. a wireless audio communication link. The communication link may be based on any appropriate (e.g. short range), proprietary or standardized, communication technology, e.g. Bluetooth or Bluetooth Low Energy, Ultra-WideBand (UWB), NFC, etc.
The earpiece may comprise
The earpiece may comprise at least one input transducer, e.g. a microphone. The earpiece may comprise at least two input transducers, e.g. microphones.
The separate audio processing device may comprise the processing unit.
The separate audio processing device may comprise the encoder.
The earpiece may comprise the, or an, encoder. The earpiece and the separate audio processing device may comprise (possibly identical) encoder units. Thereby the transmission from the separate audio processing device to the earpiece can be limited to appropriate gains (representing attenuation of amplification of the (encoded) electric input signal in the second domain) for application to the stream of samples of the electric input signal in a second domain (in the earpiece).
The earpiece may comprise the decoder.
The separate audio processing device may comprise the decoder.
The output unit may comprise a number of electrodes of a cochlear implant type hearing aid, or a vibrator of a bone conducting hearing aid, or a loudspeaker of an air conduction-based hearing aid.
The hearing device (e.g. a hearing aid) may be adapted to provide a frequency dependent gain and/or a level dependent compression and/or a transposition (with or without frequency compression) of one or more frequency ranges to one or more other frequency ranges, e.g. to compensate for a hearing impairment of a user. The hearing device may comprise a signal processor for enhancing the input signals and providing a processed output signal.
The hearing device may comprise an output unit for providing a stimulus perceived by the user as an acoustic signal based on a processed electric signal. The output unit may comprise a number of electrodes of a cochlear implant (for a CI type hearing aid) or a vibrator of a bone conducting hearing aid. The output unit may comprise an output transducer. The output transducer may comprise a receiver (loudspeaker) for providing the stimulus as an acoustic signal to the user (e.g. in an acoustic (air conduction based) hearing aid). The output transducer may comprise a vibrator for providing the stimulus as mechanical vibration of a skull bone to the user (e.g. in a bone-attached or bone-anchored hearing aid).
The hearing device may comprise an input unit for providing an electric input signal representing sound. The input unit may comprise an input transducer, e.g. a microphone, for converting an input sound to an electric input signal. The input unit may comprise a wireless receiver for receiving a wireless signal comprising or representing sound and for providing an electric input signal representing said sound. The wireless receiver may e.g. be configured to receive an electromagnetic signal in the radio frequency range (3 kHz to 300 GHz). The wireless receiver may e.g. be configured to receive an electromagnetic signal in a frequency range of light (e.g. infrared light 300 GHz to 430 THz, or visible light, e.g. 430 THz to 770 THz).
The hearing device may comprise a directional microphone system adapted to spatially filter sounds from the environment, and thereby enhance a target acoustic source among a multitude of acoustic sources in the local environment of the user wearing the hearing device. The directional system may be adapted to detect (such as adaptively detect) from which direction a particular part of the microphone signal originates. This can be achieved in various different ways as e.g. described in the prior art. In hearing devices, a microphone array beamformer is often used for spatially attenuating background noise sources. Many beamformer variants can be found in literature. The minimum variance distortionless response (MVDR) beamformer is widely used in microphone array signal processing. Ideally the MVDR beamformer keeps the signals from the target direction (also referred to as the look direction) unchanged, while attenuating sound signals from other directions maximally. The generalized sidelobe canceller (GSC) structure is an equivalent representation of the MVDR beamformer offering computational and numerical advantages over a direct implementation in its original form.
The hearing device may comprise antenna and transceiver circuitry allowing a wireless link to an entertainment device (e.g. a TV-set), a communication device (e.g. a telephone), a wireless microphone, or another hearing device, etc. The hearing device may thus be configured to wirelessly receive a direct electric input signal from another device. Likewise, the hearing device may be configured to wirelessly transmit a direct electric output signal to another device. The direct electric input or output signal may represent or comprise an audio signal and/or a control signal and/or an information signal.
In general, a wireless link established by antenna and transceiver circuitry of the hearing device can be of any type. The wireless link may be a link based on near-field communication, e.g. an inductive link based on an inductive coupling between antenna coils of transmitter and receiver parts. The wireless link may be based on far-field, electromagnetic radiation. Preferably, frequencies used to establish a communication link between the hearing device and the other device is below 70 GHz, e.g. located in a range from 50 MHz to 70 GHz, e.g. above 300 MHz, e.g. in an ISM range above 300 MHz, e.g. in the 900 MHz range or in the 2.4 GHz range or in the 5.8 GHz range or in the 60 GHz range (ISM=Industrial, Scientific and Medical, such standardized ranges being e.g. defined by the International Telecommunication Union, ITU). The wireless link may be based on a standardized or proprietary technology. The wireless link may be based on Bluetooth technology (e.g. Bluetooth Low-Energy technology), or Ultra-WideBand (UWB) technology.
The hearing device may be or form part of a portable (i.e. configured to be wearable) device, e.g. a device comprising a local energy source, e.g. a battery, e.g. a rechargeable battery. The hearing device may e.g. be a low weight, easily wearable, device, e.g. having a total weight less than 500 g (e.g. a separate processing device of the hearing aid), e.g. less than 100 g, such as less than 20 g, such as less than 5 g (e.g. an earpiece of the hearing aid).
The hearing device may comprise a ‘forward’ (or ‘signal’) path for processing an audio signal between an input and an output of the hearing device. A signal processor may be located in the forward path. The signal processor may be adapted to provide a frequency dependent gain according to a user's particular needs (e.g. hearing impairment). The hearing device may comprise an ‘analysis’ path comprising functional components for analyzing signals and/or controlling processing of the forward path. Some or all signal processing of the analysis path and/or the forward path may be conducted in the frequency domain, in which case the hearing device comprises appropriate analysis and synthesis filter banks. Some or all signal processing of the analysis path and/or the forward path may be conducted in the time domain.
An analogue electric signal representing an acoustic signal may be converted to a digital audio signal in an analogue-to-digital (AD) conversion process, where the analogue signal is sampled with a predefined sampling frequency or rate fs, fs being e.g. in the range from 8 kHz to 48 kHz (adapted to the particular needs of the application) to provide digital samples xn (or x[n]) at discrete points in time tn (or n), each audio sample representing the value of the acoustic signal at tn by a predefined number Nb of bits, Nb being e.g. in the range from 1 to 48 bits, e.g. 24 bits. Each audio sample is hence quantized using Nb bits (resulting in 2Nb different possible values of the audio sample). A digital sample x has a length in time of 1/fs, e.g. 50 μs, for fs=20 kHz. A number of audio samples may be arranged in a time frame. A time frame may comprise 64 or 128 audio data samples. Other frame lengths may be used depending on the practical application.
The hearing device may comprise an analogue-to-digital (AD) converter to digitize an analogue input (e.g. from an input transducer, such as a microphone) with a predefined sampling rate, e.g. 20 kHz. The hearing devices may comprise a digital-to-analogue (DA) converter to convert a digital signal to an analogue output signal, e.g. for being presented to a user via an output transducer.
The hearing device, e.g. the input unit, and or the antenna and transceiver circuitry may comprise a transform unit for converting a time domain signal to a signal in the transform domain (e.g. frequency domain or Laplace domain, etc.). The transform unit may be constituted by or comprise a TF-conversion unit for providing a time-frequency representation of an input signal. The time-frequency representation may comprise an array or map of corresponding complex or real values of the signal in question in a particular time and frequency range.
The frequency range considered by the hearing device from a minimum frequency fmin to a maximum frequency fmax may comprise at least a part of the typical human audible frequency range from 20 Hz to 20 kHz, e.g. a part of the range from 20 Hz to 12 kHz. Typically, a sample rate fs is larger than or equal to twice the maximum frequency fmax, fs≥2fmax.
The hearing device may be configured to operate in different modes, e.g. a normal mode and one or more specific modes, e.g. selectable by a user, or automatically selectable. A mode of operation may be optimized to a specific acoustic situation or environment. A mode of operation may include a low-power mode, where functionality of the hearing device is reduced (e.g. to save power), e.g. to disable wireless communication, and/or to disable specific features of the hearing device.
The hearing device may comprise a number of detectors configured to provide status signals relating to a current physical environment of the hearing device (e.g. the current acoustic environment), and/or to a current state of the user wearing the hearing device, and/or to a current state or mode of operation of the hearing device. Alternatively or additionally, one or more detectors may form part of an external device in communication (e.g. wirelessly) with the hearing device. An external device may e.g. comprise another hearing device, a remote control, and audio delivery device, a telephone (e.g. a smartphone), an external sensor, etc.
One or more of the number of detectors may operate on the full band signal (time domain). One or more of the number of detectors may operate on band split signals ((time-) frequency domain), e.g. in a limited number of frequency bands.
The number of detectors may comprise a level detector for estimating a current level of a signal of the forward path. The detector may be configured to decide whether the current level of a signal of the forward path is above or below a given (L-)threshold value. The level detector operates on the full band signal (time domain). The level detector operates on band split signals ((time-) frequency domain).
The hearing device may comprise a voice activity detector (VAD) for estimating whether or not (or with what probability) an input signal comprises a voice signal (at a given point in time). A voice signal may in the present context be taken to include a speech signal from a human being. It may also include other forms of utterances generated by the human speech system (e.g. singing). The voice activity detector unit may be adapted to classify a current acoustic environment of the user as a VOICE or NO-VOICE environment. This has the advantage that time segments of the electric microphone signal comprising human utterances (e.g. speech) in the user's environment can be identified, and thus separated from time segments only (or mainly) comprising other sound sources (e.g. artificially generated noise). The voice activity detector may be adapted to detect as a VOICE also the user's own voice. Alternatively, the voice activity detector may be adapted to exclude a user's own voice from the detection of a VOICE.
The hearing device may comprise an own voice detector for estimating whether or not (or with what probability) a given input sound (e.g. a voice, e.g. speech) originates from the voice of the user of the system. A microphone system of the hearing device may be adapted to be able to differentiate between a user's own voice and another person's voice and possibly from NON-voice sounds.
The number of detectors may comprise a movement detector, e.g. an acceleration sensor. The movement detector may be configured to detect movement of the user's facial muscles and/or bones, e.g. due to speech or chewing (e.g. jaw movement) and to provide a detector signal indicative thereof.
The hearing device may comprise a classification unit configured to classify the current situation based on input signals from (at least some of) the detectors, and possibly other inputs as well. In the present context ‘a current situation’ may be taken to be defined by one or more of
The classification unit may be based on or comprise a neural network, e.g. a trained neural network.
The hearing device may comprise an acoustic (and/or mechanical) feedback control (e.g. suppression) or echo-cancelling system. Adaptive feedback cancellation has the ability to track feedback path changes over time. It is typically based on a linear time invariant filter to estimate the feedback path but its filter weights are updated over time. The filter update may be calculated using stochastic gradient algorithms, including some form of the Least Mean Square (LMS) or the Normalized LMS (NLMS) algorithms. They both have the property to minimize the error signal in the mean square sense with the NLMS additionally normalizing the filter update with respect to the squared Euclidean norm of some reference signal.
The hearing device may further comprise other relevant functionality for the application in question, e.g. compression, noise reduction, etc.
The hearing device may comprise a hearing instrument, e.g. a hearing instrument adapted for being located at the ear or fully or partially in the ear canal of a user, e.g. a headset, an earphone, an ear protection device or a combination thereof. A hearing system may comprise a speakerphone (comprising a number of input transducers and a number of output transducers, e.g. for use in an audio conference situation), e.g. comprising a beamformer filtering unit, e.g. providing multiple beamforming capabilities.
In an aspect, use of a hearing device, e.g. a hearing aid, as described above, in the ‘detailed description of embodiments’ and in the claims, is moreover provided. Use may be provided in a hearing system comprising one or more hearing aids (e.g. hearing instruments, e.g. a binaural hearing aid system), headsets, ear phones, active ear protection systems, etc., e.g. in handsfree telephone systems, teleconferencing systems (e.g. including a speakerphone), public address systems, karaoke systems, classroom amplification systems, etc.
In an aspect, a method of operating a hearing aid configured to be worn by a user is furthermore provided by the present application. The method comprises
The method may further comprise
The second number of samples may be larger than the first number of samples. The encoding may be trained (e.g. optimized). The compensation for the user's hearing impairment may be provided by a trained neural network.
It is intended that some or all of the structural features of the device described above, in the ‘detailed description of embodiments’ or in the claims can be combined with embodiments of the method, when appropriately substituted by a corresponding process and vice versa. Embodiments of the method have the same advantages as the corresponding devices.
In an aspect, a method of training parameters of hearing aid as described above, in the ‘detailed description of embodiments’ or in the claims is furthermore provided. The method comprises
The term ‘an error’ at the output signal is in the present context taken to mean ‘a difference’ between the output of the low-latency encoder-based hearing aid and the output of the hearing aid comprising a filter bank operating in the Fourier domain.
In an aspect, a method of optimizing parameters of an encoder-/decoder-based hearing aid in order to minimize a difference between an output signal of a target encoder-/decoder-encoder-based hearing aid and an output signal of a filter bank-based hearing aid, is furthermore provided.
The encoder-/decoder-encoder-based hearing aid comprising a forward path comprises
The filter bank-based hearing aid comprising a forward path comprises
The method comprises
The method may be configured to provide that the parameters comprise one or more of weight-, bias-, and non-linear function-parameters of a neural network.
The method may be configured to provide that the parameters comprise one or more of the first and second number of samples.
The method may comprise
The term ‘parameters of a low-latency encoder-based hearing aid’ may e.g. include the weights of the encoding matrix G (i.e. the transformation matrix), or in more general terms, the weights and biases of a neural network implementing the encoder (and possible other functional parts of the low-latency encoder-based hearing aid, e.g. a processor and/or a low-latency decoder).
The filter bank-based hearing aid hearing aid comprises a forward path comprising one or more microphones (as does the low-latency encoder-based hearing aid), one or more analysis filter banks for converting the respective microphone signals from the time domain to the frequency domain, a processing unit at least comprising a hearing loss compensation algorithm for compensating for a hearing impairment of the user and providing a processed signal, and a synthesis filter bank for converting the processed signal from the frequency domain to the time domain. The filter bank-based hearing aid and the encoder-/decoder-encoder-based hearing aid according to the present disclosure being trained (e.g. optimized) may be identical in input unit(s) and output unit. The filter bank-based hearing aid and the encoder-/decoder-encoder-based hearing aid according to the present disclosure being trained may be identical in overall functionality from a user-perspective (but not in delay).
Advantages of the proposed model is that the latency of the encoder-based hearing aid according to the present disclosure can be kept at a minimum compared to traditional hearing aid processing. Training towards a hearing aid wherein the delay is higher than what is typically allowed may be applied, if, e.g., the analysis filter bank has a higher frequency resolution than what is typically allowed in a hearing aid due to latency (e.g. >64 or 128 frequency bands in the forward path).
A delay parameter D may be used to adjust for the latency difference between the filter bank-based hearing aid and the encoder-based hearing aid. The delay parameter may be substituted with an all-pass filter allowing a frequency-dependent delay.
The encoder, the processing unit, and the decoder of the low-latency encoder-based hearing aid may be trained as one deep neural network, wherein the first layers of the deep neural network correspond to the encoder, and the last layers correspond to the decoder, and the layers in-between correspond to the hearing loss compensation processing. The neural network may be trained jointly. The encoder and decoder may be trained but be kept fixed for fine tuning to an individual audiogram (where only the layers in-between are trained, e.g. trained to the specific hearing loss of the user).
The encoder and decoder may be trained to specific hearing losses.
The encoder/decoder in a binaural hearing aid system may be the same (or different) in both hearing aids.
The encoder/decoder may be part of a binaural system, where the neural network is trained jointly, e.g., in order to preserve binaural cues.
In an aspect, a tangible computer-readable medium (a data carrier) storing a computer program comprising program code means (instructions) for causing a data processing system (a computer) to perform (carry out) at least some (such as a majority or all) of the (steps of the) method described above, in the ‘detailed description of embodiments’ and in the claims, when said computer program is executed on the data processing system is furthermore provided by the present application.
By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Other storage media include storage in DNA (e.g. in synthesized DNA strands). Combinations of the above should also be included within the scope of computer-readable media. In addition to being stored on a tangible medium, the computer program can also be transmitted via a transmission medium such as a wired or wireless link or a network, e.g. the Internet, and loaded into a data processing system for being executed at a location different from that of the tangible medium.
A computer program (product) comprising instructions which, when the program is executed by a computer, cause the computer to carry out (steps of) the method described above, in the ‘detailed description of embodiments’ and in the claims is furthermore provided by the present application.
In an aspect, a data processing system comprising a processor and program code means for causing the processor to perform at least some (such as a majority or all) of the steps of the method described above, in the ‘detailed description of embodiments’ and in the claims is furthermore provided by the present application.
In a further aspect, a hearing system comprising a hearing device as described above, in the ‘detailed description of embodiments’, and in the claims, AND an auxiliary device is moreover provided.
The hearing system may be adapted to establish a communication link between the hearing device and the auxiliary device to provide that information (e.g. control and status signals, possibly audio signals) can be exchanged or forwarded from one to the other.
The auxiliary device may comprise a remote control, a smartphone, or other portable or wearable electronic device, such as a smartwatch or the like.
The auxiliary device may be constituted by or comprise a remote control for controlling functionality and operation of the hearing device(s). The function of a remote control may be implemented in a smartphone, the smartphone possibly running an APP allowing to control the functionality of the hearing device or hearing system via the smartphone (the hearing device(s) comprising an appropriate wireless interface to the smartphone, e.g. based on Bluetooth or some other standardized or proprietary scheme).
The auxiliary device may be constituted by or comprise an audio gateway device adapted for receiving a multitude of audio signals (e.g. from an entertainment device, e.g. a TV or a music player, a telephone apparatus, e.g. a mobile telephone or a computer, e.g. a PC) and adapted for selecting and/or combining an appropriate one of the received audio signals (or combination of signals) for transmission to the hearing device.
The auxiliary device may be constituted by or comprise another hearing device. The hearing system may comprise two hearing devices adapted to implement a binaural hearing system, e.g. a binaural hearing aid system.
A binaural hearing system comprising first and second hearing aids as described above, in the ‘detailed description of embodiments’ and in the claims is furthermore provided by the present application.
The binaural hearing system may be configured to provide that the separate audio processing device serve both of the first and second hearing aids. The first and second hearing aids may comprise first and second earpieces, respectively. The first and second earpieces may each comprise respective at least one encoder and a decoder. The separate audio processing device may comprise at least one encoder, and the processing unit, wherein the processing unit is configured to determine appropriate gains for application in the respective first and second earpieces to the respective stream of samples of the at least one electric input signal in the second domain, based on the at least one stream of samples of the electric input signal in the second domain from both of the first and second hearing devices.
The binaural hearing system may be embodied as shown in
In a further aspect, a non-transitory application, termed an APP, is furthermore provided by the present disclosure. The APP comprises executable instructions configured to be executed on an auxiliary device to implement a user interface for a hearing device or a hearing system described above in the ‘detailed description of embodiments’, and in the claims. The APP may be configured to run on cellular phone, e.g. a smartphone, or on another portable device allowing communication with said hearing device or said hearing system.
The APP may comprise a Latency Configuration APP may allow a user to decide how the processing according to the present disclosure is configured. The user may indicate whether a monaural (Single Hearing Aid system) or a binaural system comprising left and right hearing aids is currently relevant. The user may further for a monaural system indicate whether the hearing aid is located at the left or right ear. The user may further indicate whether an external audio processing device should be used or not. The auxiliary device and the hearing aid or hearing aids may be adapted to allow communication between them of data representative of the currently selected configuration via a, e.g. wireless, communication link.
In the present context, a hearing aid, e.g. a hearing instrument, refers to a device, which is adapted to improve, augment and/or protect the hearing capability of a user by receiving acoustic signals from the user's surroundings, generating corresponding audio signals, possibly modifying the audio signals and providing the possibly modified audio signals as audible signals to at least one of the user's ears. Such audible signals may e.g. be provided in the form of acoustic signals radiated into the user's outer ears, acoustic signals transferred as mechanical vibrations to the user's inner ears through the bone structure of the user's head and/or through parts of the middle ear as well as electric signals transferred directly or indirectly to the cochlear nerve of the user.
The hearing aid may be configured to be worn in any known way, e.g. as a unit arranged behind the ear with a tube leading radiated acoustic signals into the ear canal or with an output transducer, e.g. a loudspeaker, arranged close to or in the ear canal, as a unit entirely or partly arranged in the pinna and/or in the ear canal, as a unit, e.g. a vibrator, attached to a fixture implanted into the skull bone, as an attachable, or entirely or partly implanted, unit, etc. The hearing aid may comprise a single unit or several units communicating (e.g. acoustically, electrically or optically) with each other. The loudspeaker may be arranged in a housing together with other components of the hearing aid, or may be an external unit in itself (possibly in combination with a flexible guiding element, e.g. a dome-like element).
A hearing aid may be adapted to a particular user's needs, e.g. a hearing impairment. A configurable signal processing circuit of the hearing aid may be adapted to apply a frequency and level dependent compressive amplification of an input signal. A customized frequency and level dependent gain (amplification or compression) may be determined in a fitting process by a fitting system based on a user's hearing data, e.g. an audiogram, using a fitting rationale (e.g. adapted to speech). The frequency and level dependent gain may e.g. be embodied in processing parameters, e.g. uploaded to the hearing aid via an interface to a programming device (fitting system), and used by a processing algorithm executed by the configurable signal processing circuit of the hearing aid.
A ‘hearing system’ refers to a system comprising one or two hearing aids, and a ‘binaural hearing system’ refers to a system comprising two hearing aids and being adapted to cooperatively provide audible signals to both of the user's ears. Hearing systems or binaural hearing systems may further comprise one or more ‘auxiliary devices’, which communicate with the hearing aid(s) and affect and/or benefit from the function of the hearing aid(s). Such auxiliary devices may include at least one of a remote control, a remote microphone, an audio gateway device, an entertainment device, e.g. a music player, a wireless communication device, e.g. a mobile phone (such as a smartphone) or a tablet or another device, e.g. comprising a graphical interface. Hearing aids, hearing systems or binaural hearing systems may e.g. be used for compensating for a hearing-impaired person's loss of hearing capability, augmenting or protecting a normal-hearing person's hearing capability and/or conveying electronic audio signals to a person. Hearing aids or hearing systems may e.g. form part of or interact with public-address systems, active ear protection systems, handsfree telephone systems, car audio systems, entertainment (e.g. TV, music playing or karaoke) systems, teleconferencing systems, classroom amplification systems, etc.
Embodiments of the disclosure may e.g. be useful in applications such as hearing aids and headsets.
The aspects of the disclosure may be best understood from the following detailed description taken in conjunction with the accompanying figures. The figures are schematic and simplified for clarity, and they just show details to improve the understanding of the claims, while other details are left out. Throughout, the same reference numerals are used for identical or corresponding parts. The individual features of each aspect may each be combined with any or all features of the other aspects. These and other aspects, features and/or technical effect will be apparent from and elucidated with reference to the illustrations described hereinafter in which:
The figures are schematic and simplified for clarity, and they just show details which are essential to the understanding of the disclosure, while other details are left out. Throughout, the same reference signs are used for identical or corresponding parts.
Further scope of applicability of the present disclosure will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only. Other embodiments may become apparent to those skilled in the art from the following detailed description.
The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. Several aspects of the apparatus and methods are described by various blocks, functional units, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as “elements”). Depending upon particular application, design constraints or other reasons, these elements may be implemented using electronic hardware, computer program, or any combination thereof.
The electronic hardware may include micro-electronic-mechanical systems (MEMS), integrated circuits (e.g. application specific), microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), gated logic, discrete hardware circuits, printed circuit boards (PCB) (e.g. flexible PCBs), and other suitable hardware configured to perform the various functionality described throughout this disclosure, e.g. sensors, e.g. for sensing and/or registering physical properties of the environment, the device, the user, etc. Computer program shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.
The present application relates to the field of hearing devices. The disclosure relates in particular to such devices configured to have a low delay in the processing of audio signals.
[Luo et al.; 2019] describe a scheme for speaker-independent speech separation using a fully convolutional time-domain audio separation network in a deep learning framework (DNN) for end-to-end time-domain speech separation. The DNN uses a linear encoder to generate a representation of the speech waveform optimized for separating individual speakers. Speaker separation is achieved through application of a set of weighting functions (masks) to the encoder output. The modified encoder representations are then inverted back to the waveforms using a linear decoder. The masks are found using a temporal convolutional network (TCN) consisting of stacked 1-D dilated convolutional blocks, which allows the network to model the long-term dependencies of the speech signal while maintaining a small model size.
In the block diagram of a hearing instrument (HD′) shown in
There is however a limit to how much latency a hearing device can introduce before the processed sound is significantly degraded. Typically, delays exceeding approximately 10 milliseconds (ms) are unacceptable during daily hearing device use.
The LL decoder (LL-DEC) may be jointly optimized together with the processing unit (as the processing unit will typically alter the input signal). As it rarely happens that the input signal is unaltered by the processing unit, a requirement of perfect reconstruction may be unnecessary (and the parameters of the encoder and the decoder may be utilized in a better way).
Similarly to an analysis filter bank (AFB in
A transform according to the present disclosure may be different from a Fourier transform in that the transformation matrix (G, related to encoding according to the present disclosure) is an N2×N1 matrix (cf.
The encoding/decoding functions may be linear, e.g. G(s) could be an N×T matrix, and the decoding function could be a T×N matrix, where N≥T (T being the number of samples in an input frame). A DFT (Discrete Fourier Transform) matrix is a special case of such an encoding function. The encoding/decoding functions may as well be non-linear, e.g. implemented as a neural network, e.g. as a feed-forward neural network. The neural network may be a deep neural network. Perfect reconstruction (i.e. GG−1=I, where I is a T×T identity matrix) is not a requirement.
The encoding step may be written as a matrix multiplication:
where U is a T×N matrix, and f is an optional non-linear function.
Similarly, G−1(z)=h(zW), where W is an N×T matrix, and h is an optional non-linear function.
Some examples exist in literature on the decomposition of speech into a high-dimensional space of basis vectors (i.e. basis functions), see e.g. an illustration of basis function examples in
A main concept of the present disclosure is shown in
It is thus proposed to train the parameters in a low-latency encoder/decoder hearing aid (
Advantages of the proposed model is that the latency of the encoder/decoder-based hearing aid (HD) can be kept at a minimum compared to traditional hearing aid (HD′) processing. It may even allow training towards a hearing aid wherein the delay (of the corresponding filter bank-based hearing aid) is higher than what is typically allowed (e.g. >10 ms, e.g. ≥15 ms). E.g., the analysis filter bank (AFB) may have a higher frequency resolution than what is typically allowed in a hearing aid due to latency. Such a higher resolution will e.g. allow attenuation of noise between the harmonic frequencies of a speech signal.
The delay parameter D (cf. delay element z−D inserted in the signal path between the low latency decoder (LL-DEC) and the combination unit (CU)) is used to adjust for the latency difference between the filter bank-based hearing aid and the encoder-based hearing aid (to thereby train towards a hearing aid having a lower latency while exhibiting the benefits of a larger delay (e.g. increased frequency resolution) in the filter bank-based hearing aid). The delay parameter may be substituted with an all-pass filter allowing a frequency-dependent delay. The encoder-based hearing aid (HD) may be trained as one deep neural network, wherein the first layers correspond to the encoder, and the last layers correspond to the decoder. Layers in-between correspond to the noise reduction and hearing loss compensation processing. The network may be trained jointly. In an embodiment the encoder and decoder are trained but may be kept fixed for fine tuning to an individual audiogram (where only the layers in-between are trained). The layers corresponding to the low-latency-encoder and/or of the low-latency-decoder may e.g. be implemented as a feed forward neural network. The layers corresponding to the hearing loss compensation (etc.) may e.g. be implemented as a recurrent neural network.
In the exemplary training setup of
The main objective of the training is to provide that the low-latency hearing instrument in the lower part of
The gained lower latency may be used to compensate for an additional transmission delay, in the case the signals or encoded features partly or fully are processed in an external device. The external device may contain additional microphones, or it may base its calculations on signals from more than one hearing aid, such as a pair of hearing aids mounted on the left and the right ear. Different examples are shown in
The thereby provided lower latency of processing (cf. processing unit PRO in dotted enclosure of the external audio processing device (ExD)) may compensate for the transmission delay incurred by the communication link (LNK) between the earpiece (EP) of the hearing instrument and the external audio processing device (ExD). Hereby the hearing instrument (HD) has access to more processing power compared to local processing in the earpiece (EP), e.g. to better enable computation intensive tasks, e.g. related to neural network computations.
The parameters of the external audio processing device (ExD) of
The encoder (LL-ENC) may be implemented with real-valued weights or alternatively with complex-valued weights.
The earpiece (EP) and the external audio processing device (ExD) may be connected by an electric cable. The link (LNK) may, however, be a short-range wireless (e.g. audio) communication link, e.g. based on Bluetooth, e.g. Bluetooth Low Energy, or Ultra-Wide Band (UWB) technology.
In the above description, the earpiece (EP) and the external audio processing device (ExD) are assumed to form part of the hearing device (HD). The external audio processing device (ExD) may be constituted by a dedicated, preferably portable, audio processing device, e.g. specifically configured to carry out (at least) more processing intensive tasks of the hearing device.
The external audio processing device (ExD) may be portable communication device, e.g. a smartphone, adapted to carry out processing tasks of the earpiece, e.g. via an application program (APP), but also dedicated to other tasks that are not directly related to the hearing device functionality.
The earpiece (EP) may comprise more functionality than shown in the embodiment of
The earpiece (EP) may e.g. comprise a forward path that is used in a certain mode of operation, when the external audio processing device (ExD) is not available (or intentionally not used). In such case the earpiece (EP) may perform the normal function of the hearing device.
The hearing device (HD) may be constituted by a hearing aid (hearing instrument) or a headset.
Compared to the embodiment of
In an embodiment, a hearing device (HD) is provided which is configured to switch between two modes of operation implementing the embodiments of
In an embodiment, spatial cues, such as interaural time differences or interaural level differences are part of the cost function in the optimization process. E.g. the interaural time difference between the left and the right target signals and the estimated left and right target signals may be implemented as a term in the cost function. Alternatively, the interaural transfer functions of the clean speech or the noise may be included in the cost function, in order to preserve spatial cues.
The hearing aid (HD) exemplified in
The hearing aid (HD) may comprise a directional microphone system adapted to enhance a target acoustic source relative to a multitude of acoustic sources in the local environment of the user wearing the hearing aid device (e.g. based on the electric input signals from two or more of the microphones (M1, M2, MITE). The memory unit (MEM) may comprise predefined (or adaptively determined) complex, frequency dependent constants defining predefined or (or adaptively determined) beam patterns, etc.
The memory (MEM) may e.g. comprise data related to the user, e.g. preferred settings.
The hearing aid of
The hearing aid (HD) according to the present disclosure may comprise a user interface UI, e.g. as shown in the lower left part of
The auxiliary device may e.g. be constituted by or comprise the external audio processing device (ExD).
Other aspects related to the control of hearing aid (e.g. the beamformer), the volume setting, specific hearing aid programs for a given listening situation, etc.) may be made selectable or configurable from the user interface (UI). The user interface may e.g. be configured to allow a user to decide on specific modes of operation of the latency setup, cf. e.g. as discussed in connection with
It is intended that the structural features of the devices described above, either in the detailed description and/or in the claims, may be combined with steps of the method, when appropriately substituted by a corresponding process.
As used, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well (i.e. to have the meaning “at least one”), unless expressly stated otherwise. It will be further understood that the terms “includes,” “comprises,” “including,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, but an intervening element may also be present, unless expressly stated otherwise. Furthermore, “connected” or “coupled” as used herein may include wirelessly connected or coupled. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. The steps of any disclosed method are not limited to the exact order stated herein, unless expressly stated otherwise.
It should be appreciated that reference throughout this specification to “one embodiment” or “an embodiment” or “an aspect” or features included as “may” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. Furthermore, the particular features, structures or characteristics may be combined as suitable in one or more embodiments of the disclosure. The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects.
The claims are not intended to be limited to the aspects shown herein but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21177675.2 | Jun 2021 | EP | regional |
This application is a Continuation of copending application Ser. No. 17/831,807, filed on Jun. 3, 2022, which claims priority under 35 U.S.C. § 119(a) to Application No. 21177675.2, filed in Europe on Jun. 4, 2021, all of which are hereby expressly incorporated by reference into the present application.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17831807 | Jun 2022 | US |
| Child | 18647406 | US |
