Patent Grant
11843917
The present disclosure deals with hearing devices, e.g. hearing aids or headsets adapted to be worn at or in an ear of a user. The present disclosure deals in particular with a scheme for preserving Pinna cues in the signal presented to the user as picked up by an input transducer located in an ear canal of the user.
In IIC (Invisible-In-Canal) and CIC (Completely-In-Canal) style hearing devices it is currently not possible to do traditional beamforming, since there is typically only one microphone in such devices. Binaural beamforming has been suggested, but it comes with some of the latency problems and loss of cues that binaural beamformers are known to lead to.
In BTE (Behind-The-Ear) and RITE (Receiver-in-The-Ear) style hearing devices, beamformers can allow an amplification larger than possible in IIC and CIC style hearing devices (before feedback is a problem), making them suitable for use by persons having a bigger hearing loss. They can also create a pinna model, which provides directional listening information to the listener in all listening situations (cf. e.g. US20170295436A1). However, there are limitations to these BTE/RITE pinna models in that they only provide 2D information from the horizontal plane, whereas the Pinna provides 3D location information and the accuracy of current 2D models is to some extent of a lesser quality than similar pinna location information. Experiments (cf. e.g. [Roffler & Butler; 1968]) have shown that high frequency pinna cues are necessary in order to accurately localize sounds in the vertical plane.
EP2262285A1 deals with a hearing aid comprising a directionality system for providing a weighted sum of at least two microphone signals thereby providing at least two directional microphone signals having maximum sensitivity in spatially different directions and a combined microphone signal, and a frequency shaping-unit for modifying the combined microphone signal to indicate directional cues of input sounds originating from at least one of said spatially different directions and providing an improved directional output signal.
The present disclosure combines the strengths of CIC and BTE/miniRITE hearing devices. It takes the Pinna cues from the CIC device (placed ideally at the anatomical ear canal opening) and combines with the beamforming and higher amplification levels of the BTE/miniRITE style hearing devices.
The present disclosure solves the problem of providing sufficient amplification for a wide range of people with hearing loss, while still maintaining the Pinna cues.
Sound can be decomposed into an envelope and fine structure, which can be modified independently before being combined again into a final output signal.
The sound picked up by a microphone located in the ear canal (as in a CIC or IIC-style hearing device) is not used for amplification—only the envelope of the incoming sound is used and combined with the fine structure of an “enhanced omnidirectional” sound from microphones in a RITE/BTE-type hearing device. This combination can be done in several ways—either mathematically, following the inverse of the decomposition into envelope and phase, or it can be applied after beamforming, e.g. using a post filter.
In this way the amplified output of the hearing device is more resembling the “BTE/RITE sound” than “the CIC sound” and therefore more amplification can be applied with less risk for feedback. At the same time, the sound from the BTE/RITE is enriched by the pinna cues from the CIC microphone position.
The application of the extracted pinna cues to the first electric input signal (or to a signal derived therefrom) may be made dependent on feedback estimate(s) provided by a feedback estimator, or it may be made dependent on the selection of a specific mode of operation (e.g. a specific hearing aid program), e.g. selected from a user interface.
A Hearing Aid:
In an aspect of the present application, a hearing aid configured to be worn at, and/or in, an ear of a user is provided. The hearing aid comprises a forward path for processing sound from the environment of the user. The forward path comprises
The hearing aid may further comprise at least one second microphone connected to said audio signal processor, the at least one second microphone being configured to provide at least one second electric input signal representing said sound as received at the at least one second microphone, the at least one second microphone being located at or in said first ear canal of the user. The hearing aid may further comprise that a feature extractor for extracting acoustic characteristics of said ear of the user from said at least one second electric input signal, or a signal originating therefrom. The hearing aid may be configured to include said acoustic characteristics in the processed signal.
Thereby an improved hearing aid may be provided.
The acoustic characteristics of said ear, also termed ‘pinna cues’ are dominated by phase modifications of the acoustic signal impinging on the ear (pinna) at relatively low frequencies (below a LF-HF-threshold frequency, fLF-HF) and are dominated by amplitude modifications at relatively high frequencies (above the LF-HF-threshold frequency, fLF-HF). The border frequency between low and high frequencies may in the present context be larger than 1 kHz, e.g. in the range between 1 kHz and 4 kHz, e.g. around 2 kHz. The threshold frequency may be different for different persons (ears).
The feature extractor for extracting acoustic characteristics of an ear of the user may e.g. be configured to extract acoustic characteristics as magnitude and phase properties (the combination of both can be represented as a complex value).
The feature extractor for extracting acoustic characteristics of an ear of the user may e.g. be configured to focus on phase properties of the acoustic characteristics in a first frequency range. The feature extractor for extracting acoustic characteristics of an ear of the user may e.g. be configured to focus on magnitude properties of the acoustic characteristics in a second frequency range. The feature extractor for extracting acoustic characteristics of an ear of the user may e.g. be configured to focus on phase properties of the acoustic characteristics below a LF-HF-threshold frequency (fLF-HF) and to focus on magnitude properties of the acoustic characteristics above the LF-HF-threshold frequency. The feature extractor for extracting acoustic characteristics of an ear of the user may e.g. be configured to include magnitude and phase properties of the acoustic characteristics below a LF-HF-threshold frequency (fLF-HF) and to focus on magnitude properties of the acoustic characteristics above the LF-HF-threshold frequency. The LF-HF-threshold frequency (fLF-HF) may e.g. be below 2.5 kHz, such as below 2 kHz, such as in a range between 1 kHz and 2 kHz.
Considering the phase of the acoustic characteristics (‘pinna cues’) (as opposed to only its magnitude) may provide more precise pinna model, in particular in a frequency range below 2 kHz.
Since a person's hearing loss typically increases with frequency, it is advantageous for a hearing impaired person that the pinna model is as precise as possible in the frequencies where the hearing loss is relatively smaller (lower frequencies).
The hearing aid may comprise only one second microphone.
The hearing aid may comprise only one first microphone.
The (or at least one of the) at least one first microphones may be located in the contralateral ear canal or at the contralateral ear, and the at least one second microphone may be located in the ipsilateral ear canal.
The feature extractor may comprise an envelope extractor for extracting said acoustic characteristics, the envelope extractor being configured to determine an envelope and/or envelope cues of the at least one second electric input signal, or a signal originating therefrom, and to provide an envelope signal representative thereof. The audio signal processor may be configured to include said acoustic characteristics in the processed signal in dependence of the envelope signal.
The term “envelope” is in the present context taken to mean “a smoothing curve outlining the extremes of a signal”.
The fine structure may as well be extracted by the Hilbert transform, referred to as the Hilbert fine structure. Phase modifications can be applied to the at least one first electric input signals using a complex exponential, e.g. via complex postfilter gains.
The audio signal processor may be configured to apply said envelope or envelope cues to said at least one first electric input signal, or to a signal originating therefrom. The audio signal processor may be configured to substitute a current envelope of the at least one first electric input signal, or a signal originating therefrom, by the current envelope determined for the at least one second electric input signal.
The audio signal processor may be configured to apply said envelope or envelope cues to said at least one first electric input signal, or to a signal originating therefrom, only above an LF-HF-threshold frequency, fLF-HF.
The audio signal processor may be configured to apply said envelope or envelope cues to said at least one first electric input signal, or to a signal originating therefrom, only below an LF-HF-threshold frequency, fLF-HF.
The hearing aid may comprise at least two first microphones providing respective at least two first electric input signals wherein the audio signal processor comprises a directional system for providing at least one beamformer comprising predefined and/or adaptively updated beamformer weights, and for providing at least one beamformed signal in dependence of said at least two first electric input signals and said at least one beamformer. The processed signal may be provided in dependence of said at least one beamformed signal, or a signal or signals originating therefrom. The audio signal processor may be configured to include the acoustic characteristics extracted from the at least one second electric input signal, or a signal originating therefrom, in the at least one beamformed signal, or a signal or signals originating therefrom.
The hearing aid may comprise a postfilter for filtering said at least one electric input signal or said beamformed signal, or a signal originating therefrom, based on adaptively updated postfilter gains and configured to provide a filtered signal.
The postfilter gains may be complex values (including magnitude and phase).
The postfilter may be configured to determine postfilter gains in dependence of the extracted acoustic characteristics.
The postfilter may be configured to determine the postfilter gains in dependence of the envelope signal. The postfilter may be connected to the envelope extractor and configured to receive the envelope signal. The envelope of the at least one second electric input signal may e.g. be extracted by a standard signal processing procedure, such as low-pass filtering of the (e.g. squared) magnitude of the signal, or by applying the Hilbert transform to the at least one second electric input signal, etc. The envelope cues may e.g. comprise amplitude differences between the different microphone signals. Such amplitude differences may be sound source direction dependent, and thus encode important pinna cues. Application of the envelope cues can be done either by means of the absolute envelope or by means of the envelope difference between (one or more of) the at least one second electric input signal and (one or more of) the at least two first electric input signal.
The feature extractor may be configured to determine said acoustic characteristics of the ear of the user in dependence of a level difference measure indicative of a difference in level between the at least one second electric input signal and the at least one first electric input signal. An estimate of the (level contribution to the) acoustic characteristics of the ear may e.g. be provided by a level difference measure relating to the difference in level between the at least one second electric input signal and the at least one first electric input signal, e.g. ΔL=L2−L1, where L2 is a current level of a second microphone signal and L1 is a current level of a first microphone signal.
The feature extractor may also be configured to determine said acoustic characteristics of the ear of the user in dependence of a phase difference between the at least one second electric input signal and the at least one first electric input signal. An estimate of the (phase contribution to the) acoustic characteristics of the ear may e.g. be provided by a phase difference measure relating to the difference in phase between the at least one second electric input signal and the at least one first electric input signal, e.g. ΔP=P2−P1, where P2 is a current phase of a second microphone signal and P1 is a current phase of a first microphone signal.
The postfilter may be configured to determine said postfilter gains in dependence of the level and/or phase difference measures. The postfilter gain (at a given frequency) may increase with increasing level difference measure (e.g. ΔL=L2−L1). The postfilter gain (at a given frequency) may decrease with decreasing level difference measure (e.g. ΔL=L2−L1). The postfilter gain (at a given frequency) may be proportional to the level difference measure (e.g. ΔL=L2−L1). The postfilter gain (at a given frequency) may be a smooth function of the level difference measure. The postfilter gain (at a given frequency) may be represented by a piecewise linear function. The postfilter gain (at a given frequency) may include a cap beyond which the gain does not increase (or decrease) further for increasing (or decreasing) level or phase difference measure (e.g. ΔL=L2−L1, ΔP=P2−P1).
The (frequency dependent) envelope (level) differences may be approximated by level differences directly (as the envelope level values can be approximated as smoothed signal levels). Thereby a relatively simple (frequency dependent) envelope difference-to-postfilter gain determination (providing spatial cues to the at least one first electric input signal (or a signal derived therefrom) can be provided.
The audio signal processor may be configured to apply a frequency and/or level dependent gain according to the user's needs to the at least one first electric input signal, or to a signal or signals originating therefrom, and to provide the processed signal in dependence thereof. The audio signal processor may be configured to base the processed signal on the filtered signal from the postfilter. In other words, the audio signal processor may be connected to (or comprise) the postfilter.
The hearing aid may comprise a BTE-part adapted for being located at or behind an ear (pinna) of the user, and wherein the at least one first microphones is located in the BTE-part.
The hearing aid may comprise an ITE-part adapted for being located at or in an ear canal of the user, and wherein the at least one second microphone is located in the ITE-part.
The output transducer may be located in the ITE-part.
The hearing aid may comprise a feedback control system for estimating and/or attenuating feedback from the output transducer to one or more of the at least one first microphones and the at least one second microphone. The feedback control system may comprise a feedback path estimator for providing a feedback estimate representative of feedback from the output transducer to one or more of the at least one second microphone.
The feedback control system may be configured to provide a reliability estimate of the at least one second electric input signal in dependence of the feedback estimate. The reliability estimate may be provided in absolute terms for (one or more of) the at least one second electric input signals. The reliability estimate may be provided as a relative measure, e.g. between (one or more of) the at least one second electric input signal and one or more of the at least one first electric input signal.
In case the feedback estimate(s) from the output transducer to the at least one second microphone is considered to be non-critical, the processed signal of the audio signal processor may be based on (such as exclusively based on) said at least one second electric signal or a signal derived therefrom. In such case the extraction of pinna cues and application to the at least one first electric signal or a signal derived therefrom may be dispensed with.
The application of the extracted pinna cues to the first electric input signal (or to a signal derived therefrom) may be made dependent on feedback estimate(s) provided by a feedback estimator, or it may be made dependent on the selection of a specific mode of operation (e.g. a specific hearing aid program), e.g. selected from a user interface.
The hearing aid may be constituted by or comprise an air-conduction type hearing aid, a bone-conduction type hearing aid, a cochlear implant type hearing aid, or a combination thereof.
The 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 aid may comprise a signal processor for enhancing the input signals and providing a processed output signal.
The hearing aid 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 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 aid 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 aid 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 aid. 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 aids, 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 aid 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 aid, etc. The hearing aid may thus be configured to wirelessly receive a direct electric input signal from another device. Likewise, the hearing aid 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 aid 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 aid 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). The wireless link may be based on ultra wide band (UWB) technology.
The hearing aid 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 aid may e.g. be a low weight, easily wearable, device, e.g. having a total weight less than 100 g, such as less than 20 g.
The hearing aid may comprise a ‘forward’ (or ‘signal’) path for processing an audio signal between an input and an output of the hearing aid. 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 aid 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 aid 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 aid 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 aids 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 aid, e.g. the input unit, and or the antenna and transceiver circuitry may 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 TF conversion unit may comprise a filter bank for filtering a (time varying) input signal and providing a number of (time varying) output signals each comprising a distinct frequency range of the input signal. The TF conversion unit may comprise a Fourier transformation unit for converting a time variant input signal to a (time variant) signal in the (time-)frequency domain. The frequency range considered by the hearing aid from a minimum frequency fmin to a maximum frequency fmax may comprise 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. A signal of the forward and/or analysis path of the hearing aid may be split into a number NI of frequency bands (e.g. of uniform width), where NI is e.g. larger than 5, such as larger than 10, such as larger than 50, such as larger than 100, such as larger than 500, at least some of which are processed individually. The hearing aid may be adapted to process a signal of the forward and/or analysis path in a number NP of different frequency channels (NP≤NI). The frequency channels may be uniform or non-uniform in width (e.g. increasing in width with frequency), overlapping or non-overlapping.
The hearing aid 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 aid is reduced (e.g. to save power), e.g. to disable wireless communication, and/or to disable specific features of the hearing aid.
The hearing aid may comprise a number of detectors configured to provide status signals relating to a current physical environment of the hearing aid (e.g. the current acoustic environment), and/or to a current state of the user wearing the hearing aid, and/or to a current state or mode of operation of the hearing aid. Alternatively or additionally, one or more detectors may form part of an external device in communication (e.g. wirelessly) with the hearing aid. An external device may e.g. comprise another hearing aid, 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 aid 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 aid 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 aid 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 aid 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 aid 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 aid may further comprise other relevant functionality for the application in question, e.g. compression, noise reduction, etc.
The hearing aid 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. The hearing assistance 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.
Use:
In an aspect, use of 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 system comprising one or more hearing aids (e.g. hearing instruments), 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.
A Computer Readable Medium or Data Carrier:
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:
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.
A Data Processing System:
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.
A Hearing System:
In a further aspect, a hearing system comprising a hearing aid 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 aid 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 aid(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 aid or hearing aid system via the smartphone (the hearing aid(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 aid.
The auxiliary device may be constituted by or comprise another hearing aid. The hearing system may comprise two hearing aids adapted to implement a binaural hearing system, e.g. a binaural hearing aid system.
An APP:
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 aid 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 aid or said hearing system.
With reference to
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, e.g. hearing aids, adapted to be worn at or in an ear of a user. The present disclosure deals in particular with a scheme for preserving Pinna cues in the signal presented to the user as picked up by an input transducer located in an ear canal of the user.
A hearing device according to the present disclosure solves e.g. the problem of providing sufficient amplification for a wide range of people with hearing loss, while still maintaining the Pinna cues.
Sound can be decomposed into an envelope and fine structure, which can be modified independently before being combined again into a final output signal. An envelope can be extracted using the Hilbert transform or by low-pass filtering the magnitude or the squared magnitude of the signal. The envelope may be extracted for each frequency channel separately.
The sound picked up by a microphone located in the ear canal (as in a CIC or IIC-style hearing device) is not used for amplification—only the envelope of the incoming sound is used and combined with the fine structure of an “enhanced omnidirectional” sound from microphones in a RITE/BTE-type hearing device. This combination can be done in several ways—either mathematically, following the inverse of the decomposition into envelope and phase, or it can be applied after beamforming, e.g. using a post filter.
In this way the amplified output of the hearing device is more resembling the “BTE/RITE sound” than “the CIC sound” and therefore more amplification can be applied with less risk for feedback. At the same time, the sound from the BTE/RITE is enriched by the pinna cues from the CIC microphone position.
Various embodiments of a hearing aid comprising at least two microphones, a processor and an output transducer are schematically illustrated in
The audio signal processor (ASP) is configured to process the electric audio input signals from the input units (IN1, IN2; IN11, IN12, IN2; IN11, . . . , IN1M, IN2; IN11, . . . , IN1M, IN2, IN3), and for providing a processed (preferably enhanced) output signal (OUT). The audio signal processor (ASP) may e.g. comprise a directional algorithm (cf. e.g. BF in
All embodiments of the hearing aid are adapted for being arranged at least partly on a user's head or at least partly implanted in a user's head.
If further reduction of feedback risk is needed, the sound at the ear canal can be picked up by a directional microphone system (cf. e.g. ‘Beamformer’ in
If even further reduction of feedback is needed, an open loop feedback system can be used (shown as Feedback Cancellation for the IIC/CIC unit in the above drawing). This feedback cancellation system is somehow in an open loop, as the sound signals entering the CIC microphones are not directly amplified and presented at the receiver (loudspeaker), only the envelope is (indirectly) used to generate the BTE loudspeaker signal. Moreover, the CIC feedback cancellation system differs from the BTE feedback cancellation system; although a potential feedback problem in the CIC unit would affect the envelope extraction, it would not cause an instant stability problem as in the BTE unit, hence only a relatively slow cancellation system will likely be sufficient. The feedback cancellation system can work on the microphone signals (as illustrated in
The reliability of the in-ear microphone signal can be estimated from a feedback path estimator, either independently or relatively between the in-ear microphone and the BTE-microphones.
Application of the envelope cues can be done either by means of the absolute envelope (as described below) or by means of the envelope difference between the in-ear microphone and the BTE microphone. The latter idea may be most suitable for implementation in a post-filter type structure.
Comparison of the envelopes and fine-structure of the in-ear microphone and the BTE microphone can help estimate the time and phase delay between the microphones and thus may inform about the insertion depth of the in-ear microphone in the ear canal. This can guide the HCP during the fitting process and can also be used for training purposes or for daily quality checks and be used to give feedback to the user to help ensure more optimal benefit from the device.
The (smart) combination of the ITE and BTE parts may increase the amplification provided to the user to levels above that achievable in separate devices.
This can lead to several user benefits—better localization, better understanding of speech in competing speakers, less wind noise in the microphones and so forth.
As in
In case the feedback estimate from the output transducer (OT) to the second microphone (M2) is considered to be non-critical (e.g. evaluated by the mode control unit (MCTR) receiving the three feedback estimates (FB11, FB12, FB2)), the processed signal (OUT) of the audio signal processor (ASP, here provided by the signal processing unit (PRO)) may be based on (such as exclusively based on) the second electric signal (IN2) or (as here) on a signal derived therefrom (the feedback corrected signal ER2, which is fed to the signal processing unit (PRO) together with the feedback corrected signals ER11, ER12 originating from the two first microphones M11, M12). In such case the extraction of pinna cues and application to the at least one first electric signal or a signal derived therefrom may be dispensed with (because the cues are included in the feedback corrected signal ER2 originating from second microphone (M2)). The use of the pinna cue extraction procedure according to the present disclosure may, however, be decided on a frequency band level (so that in some frequency bands the pinna cues are extracted and applied to the first electric input signals (e.g. from BTE-microphones, or to the respective frequency bands of a beamformed signal) and in other frequency bands, the second electric input signal (e.g. from an ITE microphone) is used to provide the processed signal of the forward path (e.g. used in the beamformer to provide the beamformed signal YBF (in such frequency bands)).
The application of the extracted pinna cues to the first electric input signal(s) (or to a signal derived therefrom, e.g. YBF in
The hearing aid (HD) exemplified in
The hearing aid (HD) comprises a directional microphone system (beamformer filter (BF in
The memory (MEM) may e.g. comprise data related to the acoustic characteristics of the human ear, e.g. the ear of the user, e.g. predetermined or adaptively updated pinna gain vs. level difference data for estimating a relation between pinna gain and level difference between a second (e.g. ITE-) and (e.g. BTE-) first microphone signal according to the present disclosure. It may be advantageous to have access to complex valued pinna gains determined from differences in complex valued microphone signals.
The hearing aid of
The hearing aid (HD) according to the present disclosure may comprise a user interface UI, e.g. as shown in
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 whether or not to extract pinna cues from the second electric input signal(s) and apply them to the first electric input signal(s) (or to a signal derived therefrom, e.g. YBF in
The acoustic characteristics represented by the complex valued postfilter output may be determined from a difference between the complex valued microphone signals (IN1, IN2). The resulting complex valued acoustic characteristics (AC) of the ear may be written AC=|PG|ejPP, where PG and PP are the postfilter gain (magnitude) and phase, respectively.
When e.g. the first and second electric input signals are IN1=|IN1|ejPhase(IN1) and IN2=|IN2|ejPhase(IN2) the phase difference ΔP=Phase(IN1)−Phase(IN2) and the level difference ΔL=MAG(IN1)−MAG(IN2) in a logarithmic representation, or MAG(IN1)/MAG(IN2) in the linear-domain.
A pinna gain vs. level curve (or data representative thereof, e.g. an or functional expression may be stored in the hearing aid and be accessible to the audio signal processor, e.g. to the postfilter gain determination unit (PF-GC), cf. e.g.
The pinna gain vs. level difference data may be (is expected to be) user (ear) dependent, and may preferably be customized for a given hearing aid (e.g. during a fitting session). Alternatively (or additionally) predetermined pinna gain vs. level difference data (e.g. measured on a model ear) may by stored in a memory of the hearing aid.
The ‘pinna cues’ are typically dominated by phase modifications of the acoustic signal impinging on the ear (pinna) at relatively low frequencies (below a LF-HF-threshold frequency, fLF-HF) and are dominated by amplitude modifications at relatively high frequencies (above the LF-HF-threshold frequency, fLF-HF). The border frequency between low and high frequencies may in the present context be larger than 1 kHz, e.g. in the range between 1 kHz and 4 kHz, e.g. around 2 kHz. The threshold frequency may be different for different persons (ears). The postfilter gains may be determined as described above (from a level difference measure (e.g. ΔL=L2−L1)) for frequencies above the LF-HF-threshold frequency (fLF-HF) e.g. for frequencies above 1 kHz.
Similarly, the postfilter gains may be determined as a phase difference ΔP=P2−P1, below the LF-HF-threshold frequency (fLF-HF).
Embodiments of the disclosure may e.g. be useful in applications such as sound localization in hearing aids.
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 is 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 |
|---|---|---|---|
| 21171078 | Apr 2021 | EP | regional |
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| 20070009122 | Hamacher | Jan 2007 | A1 |
| 20100020995 | Elmedyb | Jan 2010 | A1 |
| 20140348360 | Gran | Nov 2014 | A1 |
| 20150341730 | Pedersen | Nov 2015 | A1 |
| 20170295436 | Pedersen et al. | Oct 2017 | A1 |
| Number | Date | Country |
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| 2 262 285 | Dec 2010 | EP |
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| Entry |
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| Extended European Search Report for European Application No. 22167774.3, dated Sep. 23, 2022. |
| European Search Report issued in priority application No. 21171078.5 dated Oct. 19, 2021. |
| Number | Date | Country | |
|---|---|---|---|
| 20220353623 A1 | Nov 2022 | US |
