Methods of estimating ear geometry and related hearing devices

A method for estimating an ear geometry of an ear of a user with a hearing device, the hearing device comprising an ear canal microphone, an external microphone, and a receiver, includes: obtaining an external input signal using the external microphone; providing an output signal by the receiver; obtaining an ear canal microphone input signal using the ear canal microphone; and estimating the ear geometry based on the external input signal and the ear canal microphone input signal.

RELATED APPLICATION DATA

This application claims priority to, and the benefit of, European Patent Application No. 17190783.5 filed on Sep. 13, 2017. The entire disclosure of the above application is expressly incorporated by reference herein.

FIELD

The present disclosure relates to methods of estimating ear geometry of an ear of a hearing device user with a hearing device and related hearing devices.

BACKGROUND

Hearing device manufacturers have adopted laser scanning of traditional impressions as the method of obtaining representations of the ear geometry. A dispenser acquires the impression from the patient and sends the impression directly to the manufacturer. Unfortunately, the impression can become distorted during the mailing process due to uncured material and excessive temperatures in the delivery trucks. This results an inaccurate impression of the patient's ear geometry, which in turn leads to a hearing device that does not fit properly mechanically and acoustically.

SUMMARY

Accordingly, there is a need for hearing devices capable of and methods for estimating an ear geometry of an ear of a hearing device user with a hearing device, which overcome or mitigate the disadvantages presented above.

A method for estimating an ear geometry of an ear of a hearing device user with a hearing device is disclosed. The hearing device comprises an ear canal microphone, an external microphone and a receiver. The method comprises: obtaining an external input signal with the external microphone; transmitting an output signal with the receiver. The method comprises obtaining an ear canal microphone input signal using the ear canal microphone; and estimating the ear geometry based on the external input signal and the ear canal microphone input signal.

Further, a hearing device is provided, the hearing device comprising: a set of microphones comprising an external microphone for provision of an external input signal, and an ear canal microphone for obtaining an ear canal microphone input signal; a processor for processing input signals and providing a processed output signal based on input signals; and a receiver for transmission of an output signal. The hearing device may comprise a controller configured to control hearing device settings. The hearing device is configured to estimate the ear geometry based on the external input signal and the ear canal microphone input signal.

It is an advantage of the present disclosure that the ear geometry, such as an ear canal geometry, can be estimated without having to scan the ear, prepare and send an impression to the manufacturer. This reduces significantly the likelihood of errors to propagate in the process of fitting acoustically the hearing device to the hearing device user. The fitting process at the dispenser comprises adjusting the processing of signals in the hearing device to the ear geometry of the hearing device user. Estimation of the ear geometry enables further improvement in providing a hearing device that acoustically fits the individual ear and optimizes processing of signals in the hearing device, for e.g. active noise cancellation, beamforming, compression.

A method for estimating an ear geometry of an ear of a user with a hearing device, the hearing device comprising an ear canal microphone, an external microphone, and a receiver, includes: obtaining an external input signal using the external microphone; providing an output signal by the receiver; obtaining an ear canal microphone input signal using the ear canal microphone; and estimating the ear geometry based on the external input signal and the ear canal microphone input signal.

Optionally, the act of estimating the ear geometry comprises: predicting an output response based on the external input signal and gain setting(s) of the hearing device; determining a difference between the predicted output response and the ear canal microphone input signal; and estimating the ear geometry based on the difference.

Optionally, the act of estimating the ear geometry comprises categorizing an ear canal.

Optionally, the act of estimating the ear geometry comprises determining one or more ear canal parameters.

Optionally, the one or more ear canal parameters comprises one or more of an ear canal volume, an ear canal width, an ear canal length, and an ear canal conicity.

Optionally, the one or more ear canal parameter is determined based on an estimate of real-ear unaided gain, and/or user input.

Optionally, the act of obtaining the external input signal comprises determining one or more characteristics of a signal.

Optionally, the act of obtaining the external input signal comprises determining one or more characteristics of a signal in one or more frequency bands.

Optionally, the act of obtaining the ear canal microphone input signal comprises generating the ear canal microphone input signal by the ear canal microphone

Optionally, the ear canal microphone input signal is generated in response to the output signal received by the ear canal microphone.

Optionally, the act of obtaining the ear canal microphone input signal comprises determining a forward pressure level of the ear canal microphone input signal.

Optionally, the act of determining the difference between the predicted output response and the ear canal microphone input signal is performed based on one or more hearing device configuration parameters.

Optionally, the act of determining the difference between the predicted output response and the ear canal microphone input signal is performed based on an initial hearing device calibration setting.

Optionally, the receiver is in an ear canal part of the hearing device.

Optionally, the act of obtaining the external input signal is performed in response to a measurement signal provided by an external device.

A hearing device includes: a receiver for providing of an output signal; an external microphone for providing an external input signal; an ear canal microphone for providing an ear canal microphone input signal; and a processing unit configured to estimate an ear geometry based on the external input signal and the ear canal microphone input signal.

Optionally, the processing unit is configured to estimate the ear geometry by: predicting an output response based on the external input signal and gain setting(s) of the hearing device; determining a difference between the predicted output response and the ear canal microphone input signal; and estimating the ear geometry based on the difference.

Optionally, the processing unit is configured to determine the difference between the predicted output response and the ear canal microphone input signal based on one or more hearing device configuration parameters.

Optionally, the processing unit is configured to determine the difference between the predicted output response and the ear canal microphone input signal based on an initial hearing device calibration setting.

Optionally, the processing unit is configured to estimate the ear geometry by categorizing an ear canal and/or determining one or more ear canal parameters.

DETAILED DESCRIPTION

The inventors have found that pinna is responsible for most of the variations in insertion-gain (& directional cues) across individuals, and an ear canal microphone (placed in the ear canal) actually captures most of these variations. Inventors have found that residual variance is due to the length resonance of the ear canal which is direction-independent and varies less across individuals. The present disclosure permits to find a good approximation of these individual resonances (i.e., looking at the feedback path), and thereby obtain an improved estimation of the ear geometry.

A method for estimating an ear geometry of an ear of a hearing device user with a hearing device is disclosed. The ear geometry may refer to the geometry of the ear canal. The hearing device comprises an ear canal microphone, an external microphone and a receiver. The method is performed at the hearing device. The method may be seen to relate to estimating ear geometry of an ear of the hearing device user having the hearing device placed in the ear. The method comprises obtaining an external input signal with the external microphone.

In one or more exemplary methods, obtaining an external input signal with the external microphone comprises measuring the external input signal using the external microphone. For example, obtaining an external input signal with the external microphone comprises measuring the external input signal using the external microphone and analysing the external input signal.

The method comprises transmitting an output signal with the receiver. In other words, the receiver takes as input the output signal and emits an audio output signal based on the output signal.

The method comprises obtaining an ear canal microphone input signal using the ear canal microphone. In one or more exemplary methods, the hearing device may comprise one or more ear canal microphones and obtaining an ear canal microphone input signal may be performed using the one or more ear canal microphones. The ear canal microphone input signal may be a specific measurement signal and/or an environmental signal. The measured ear canal microphone input signal may be denoted as an ear canal microphone input signal indicative of the output signal as the measured ear canal microphone input signal relates to the output signal as measured at the ear canal microphone and taken as input in the ear canal microphone. The ear canal microphone input signal may be seen as the output signal affected by the ear canal properties. The present disclosure allows quantifying the transformation of the output signal transmitted based on the measured ear canal microphone input signal (e.g. indicative of the measured output signal), which in turn results in estimation of the ear geometry.

The method comprises estimating the ear geometry based on the external input signal and the ear canal microphone input signal. The ear geometry may refer to an ear shape, ear canal dimensions, and/or properties the ear or ear canal in space. In one or more exemplary methods, the ear geometry may comprise ear dimensions, and/or ear canal type.

In one or more exemplary methods, estimating ear geometry comprises predicting an output response based on the external input signal and gain settings of the hearing device. Estimating ear geometry may comprise determining a difference between the predicted output response and the ear canal microphone input signal. Estimating ear geometry may comprise estimating the ear geometry based on the difference. Determining the difference between the predicted output response and the ear canal microphone input signal may be seen as calculating an error between the predicted output response and the measured ear canal microphone input signal. In one or more exemplary methods, determining the difference between the predicted output response and the measured output signal may comprise estimating other parameters of the ear canal, such as one or more tympanic membrane properties. Determining the difference between the predicted output response and the ear canal microphone input signal may take into account ear canal dimensions and/or hearing device configurations.

In one or more exemplary methods, estimating the ear geometry comprises categorizing an ear, such as categorizing an ear canal. For example, one or more categories may be predetermined, and possibly stored in the hearing device. A category may index one or more parameters indicative of the ear geometry or the ear canal geometry. A plurality of categories may lead to more accuracy in estimating the ear geometry. Categorizing an ear or an ear canal may be performed based on the ear canal parameter. Categorizing an ear or an ear canal may comprise identifying an ear canal type indicative of the present ear or ear canal under test. It may also be seen that categorizing an ear or an ear canal comprises estimating the ear geometry. For example, one of the one or more ear canal parameters is estimated, resulting in a categorization of the ear/ear canal. Once the category is identified, additional ear canal parameters associated with the category can be obtained.

In one or more exemplary methods, estimating the ear geometry comprises determining one or more ear canal parameters. In one or more exemplary methods, the one or more ear canal parameters comprise one or more of an ear canal length, an ear canal width, a conicity of the ear canal, and an ear canal volume. The one or more ear canal parameters may comprise an insertion depth of the ear canal microphone and/or of the receiver. In one or more exemplary methods, determining the ear canal parameter is based on an estimate of real-ear unaided gain, user input and/or acoustic measurement. For example, determining the ear canal parameter may be based on an analysis of the measured signals and the predicted output signal. For example, the input and output signals (measured by the two microphones) may be compared to estimate ear canal parameters. In determining the difference between the predicted output response and the ear canal microphone input signal, the inventors have determined that a length resonance often results in a spectral notch in the output ear canal microphone input signal at the ear canal microphone, and the frequency of this notch varies with the residual ear canal length. The ear canal length can thereby be determined. Once the frequency of the notch of the output ear canal microphone input signal at the ear canal microphone is identified, a canal length that is expected to result in a notch at this frequency is determined using the category. An appropriate real-ear insertion gain (REIG) correction for an ear canal under test may be determined based on an expected spectral difference between the locations of the ear canal microphone and the tympanic membrane. To correct the insertion gain, the method may comprise applying the inverse of the predicted real-ear insertion gain (assuming target gain is 0 dB). It may be envisaged that as predictions are not perfect, a fraction of the predicted real-ear insertion gain may be used as a conservative correction.

In one or more exemplary methods, estimating the ear geometry comprises predicting an output response based on the external input signal and gain settings, determining a difference between the predicted output response and the ear canal microphone input signal, and estimating the ear geometry based on the difference. In one or more exemplary methods, predicting the output response may be performed based on gain settings of the hearing device and/or device calibration of the hearing device (such as factory or default device calibration). Such a device calibration is performed during design/manufacturing, based on an ear simulator and/or average ear. Device calibration may include a coupler response for flat-insertion gain (CORFIG), which is a correction that is applied to the output of a hearing-aid in order to provide a flat gain when the hearing device is inserted. A standard CORFIG may be based on an average ear and thus may represent a standard measure that does not account for individual differences in ear canal geometry.

In one or more exemplary methods, determining a difference between the predicted output response and the ear canal microphone input signal comprises determining a difference between the predicted output magnitude spectrum of predicted output response and the measured output magnitude spectrum of the ear canal microphone input signal. Predicting the output response may be performed using the output signal at the receiver and/or the external input signal. It is an advantage of this disclosure that the output response may be predicted despite the fact that the reference for measuring insertion gain, i.e. Real Ear Unaided Response (REUR), is unknown. Predicting the output response may be influenced by near-field effects when the ear canal or external microphone and receiver are in very close proximity to each other. It is seen as an advantage of the present disclosure that near-field effects are accounted for because the present disclosure allows the physical ear geometry to be estimated.

In one or more exemplary methods, determining a difference between the predicted output response and the ear canal microphone input signal comprises comparing the external input signal received at the external microphone and the measured ear canal microphone input signal received at the ear canal microphone. If the receiver and the ear canal microphone responses are known, the natural resonance of the open ear canal or the effect of occluding the ear can be accounted for. Alternatively, or additionally, the ear canal microphone response can be assumed as flat and the receiver response can be assumed as approximating the open ear response. With the disclosed method, the measured transducer response (receiver to ear canal microphone) may approximate the real ear unaided response (REUR).

In one or more exemplary methods, determining the difference may comprise predicting an insertion gain by comparing the signals at the external microphone and at the ear canal microphone, and subtracting the measured transducer response (receiver to ear canal microphone).

In one or more exemplary methods, obtaining the external input signal comprises determining one or more characteristics of the external input signal. For example, a characteristic may comprise a distortion and/or a spectrum, such as an amplitude (e.g. maximum amplitude) and/or a phase.

In one or more exemplary methods, obtaining the external input signal comprises determining one or more characteristics of the ear canal microphone input signal input signal in one or more frequency bands. For example, the one or more characteristics of the external input signal are measured or determined for each frequency band separately.

In one or more exemplary methods, obtaining the ear canal microphone input signal comprises measuring the ear canal microphone input signal indicative of the output signal as received by the ear canal microphone.

In one or more exemplary methods, measuring the ear canal microphone input signal comprises determining a forward pressure level of the measured ear canal microphone input signal. Sound pressure measured by an ear canal microphone can be decomposed into forward pressure level and reflected pressure level. Determining a forward pressure level of the measured ear canal microphone input signal leads to a measurement of the ear canal microphone input signal for the further derivation of the ear geometry.

In one or more exemplary methods, determining the difference between the predicted output response and the measured ear canal microphone input signal is based on one or more hearing device configuration parameters. For example, one or more hearing device configuration parameters may comprise a receiver placement, a receiver response, an external microphone placement, an external microphone response, an ear canal microphone placement, an ear canal microphone response, a presence of venting (opening or not), placement of opening if any, a dome and/or vent size, a dome and/or vent placement, and/or an expected device insertion depth.

In one or more exemplary methods, determining the difference between the predicted output response and the measured output is based on an initial hearing device calibration setting.

In one or more exemplary methods, determining the difference between the predicted output response and the measured output is based on one or more algorithm parameters. For example, the one or more algorithm parameters may be indicative of characteristics of the algorithm, such as interaction of spectral bands, non-linearity.

In one or more exemplary methods, the receiver is placed in an ear canal part of the hearing device. In one or more exemplary methods, the hearing device comprises an ear canal microphone and an ear canal receiver, where the ear canal microphone and the receiver are placed in the ear canal part of the hearing device. These exemplary methods may provide a real-ear insertion gain (REIG) that is flat for the user. In one or more exemplary method, determining a difference between the predicted output response and the measured ear canal microphone input signal may comprise measuring the difference in transfer function from the receiver to the open-ear (REUR) and from the receiver to the external microphone (L-MiE, Lateral Microphone). The relationship between REIG, the receiver response itself (RecToEar), L-MiE and the open-ear transfer function (REUR) may be expressed in the following way:
REIG=REAR−REUR
=L-MiE+RecToEar−REUR
=L-MiE−REUR+RecToEar
=RecToEar−(REUR−L-MiE)

where REAR denotes real-ear aided response, i.e. the response when the hearing device is inserted in the ear canal of the user.

It can be seen that making the receiver response similar to the REUR−MiE response results in a flat insertion gain. The present disclosure allows a flat insertion gain to be obtained across a large number of customers and direction of arrival by just inserting the device into the ear canal. No extra equipment is needed.

In one or more exemplary methods, obtaining the external input signal comprises obtaining a specific measurement signal from an external device. The external input signal may be denoted an external microphone input signal.

The disclosed method may be performed when explicitly requested (e.g. by putting the hearing device in a calibration mode), and/or each time the device is turned on, and/or continuously.

A hearing device is disclosed. The hearing device may be a hearing aid, wherein the processor is configured to compensate for a hearing loss of a user.

The hearing device may be of the behind-the-ear (BTE) type, in-the-ear (ITE) type, in-the-canal (ITC) type, receiver-in-canal (RIC) type or receiver-in-the-ear (RITE) type. The hearing aid may be a binaural hearing aid. The hearing device may comprise a first earpiece and a second earpiece, wherein the first earpiece and/or the second earpiece is an earpiece as disclosed herein.

The hearing device may comprise an antenna for converting one or more wireless input signals, e.g. a first wireless input signal and/or a second wireless input signal, to an antenna output signal. The wireless input signal(s) origin from external source(s), such as spouse microphone device(s), wireless TV audio transmitter, and/or a distributed microphone array associated with a wireless transmitter.

The hearing device may comprise a transceiver, which may comprise a radio transceiver coupled to the antenna for converting the antenna output signal to a transceiver input signal. Wireless signals from different external sources may be multiplexed in the radio transceiver to a transceiver input signal or provided as separate transceiver input signals on separate transceiver output terminals of the radio transceiver. The hearing device may comprise a plurality of antennas and/or an antenna may be configured to be operate in one or a plurality of antenna modes. The transceiver input signal comprises a first transceiver input signal representative of the first wireless signal from a first external source.

The hearing device comprises a set of microphones. The set of microphones may comprise one or more microphones. The set of microphones comprises an external microphone for provision of an external input signal, and an ear canal microphone for obtaining an ear canal microphone input signal, which is based on the output signal transmitted by a receiver and received at the ear canal microphone. In other words, the ear canal microphone is configured to measure the ear canal microphone input signal.

The set of microphones may comprise one or more external microphones. The set of microphones may comprise one or more ear canal microphones. The set of microphones may comprise N microphones for provision of N microphone signals, wherein N is an integer in the range from 1 to 10. In one or more exemplary hearing devices, the number N of microphones is two, three, four, five or more. The set of microphones may comprise a third microphone for provision of a third microphone input signal.

In one or more exemplary hearing devices, the ear canal microphone may be positioned on the internal side of the hearing device (directed into the ear canal and facing the ear drum) and the external microphone may be positioned on the external side of the hearing device (capturing the environment). It is an advantage of the present disclosure to use these microphones, rather than a probe microphone, to measure the response inside the ear canal.

The hearing device comprises a processor for processing input signals and for providing a processed output signal based on input signals.

The hearing device comprises a receiver for transmission of an output signal and a controller configured to control hearing device settings. The hearing device is configured to estimate the ear geometry based on the external input signal and the ear canal microphone input signal.

The hearing device may be configured to estimate the ear geometry by predicting an output response based on the external input signal and gain settings of the hearing device. The hearing device may be configured to estimate the ear geometry by determining a difference between the predicted output response and the measured ear canal microphone input signal; and by estimating the ear geometry based on the difference.

In one or more exemplary hearing devices, the hearing device comprises a processing unit including the processor and the controller configured to control hearing device settings.

The present disclosure relates to a hearing device comprising an ear canal part (i.e. a part of the hearing device inserted in the ear canal of the ear) which may comprise an ear canal receiver and/or an ear canal microphone.

The present disclosure relates to a hearing-device receiver comprising a microphone-and-receiver-in-the-ear module, wherein the microphone-and-receiver in-the-ear module comprises an ear canal receiver and an ear canal microphone.

Throughout, the same reference numerals are used for identical or corresponding parts.

FIG.1is a block diagram of an exemplary hearing device according to the disclosure.

The hearing device2comprises a receiver16for transmission of an output signal15. The receiver is configured to convert the output signal15into an audio output signal11. The hearing device2comprises a set of microphones comprising an external microphone8for obtaining an external input signal9based a received signal18and providing the external input signal9to other modules of the hearing device2.

The hearing device2comprises set of microphones. The set of microphones comprise an ear canal microphone10for obtaining an ear canal microphone input signal11B, which is based on the audio signal11A as received from a receiver16. In other words, the ear canal microphone10may be configured to measure the audio signal11A because the ear canal microphone10receives the audio signal11A from the receiver16, which is then passed on as an ear canal microphone input signal11B. The audio output signal11is based on the output signal15provided by the processor14. The audio output signal11is received as audio signal11A at the ear canal microphone10is affected by the ear canal properties. This way, the disclosed hearing device is capable of estimating ear geometry, such as ear canal geometry.

The hearing device2comprises a controller12configured to control hearing device settings.

The hearing device2comprises a processor14for processing input signals and providing an output signal15. The processor14may be connected to the controller12for receiving and processing signals. The processor14is configured to compensate for a hearing loss of a user and to provide an output signal15.

The ear canal microphone10may be configured to provide ear microphone input signal11B to the controller12, and/or the processor14.

The hearing device2may comprise an antenna4for converting a first wireless input signal5of a first external source (not shown inFIG.1) to an antenna output signal. The hearing device2may comprise a transceiver7for provision of a transceiver input signal3, which may comprise a radio transceiver coupled to the antenna4for converting the antenna output signal to one or more transceiver input signals.

In one or more exemplary hearing devices, the hearing device2comprises a processing unit13including the processor14and the controller12. The processing unit13is configured to control hearing device parameters, to compensate for hearing loss.

A receiver16is configured to transmit an output signal15as an audio output signal11to be directed towards an eardrum of the hearing device user.

The hearing device2may comprise an ear canal part and another part towards the opening of the ear. In one or more exemplary hearing devices, the ear canal microphone10is positioned in the ear canal part of the hearing device2, i.e. the part facing the ear drum or tympanic membrane) and the external microphone8is positioned on the part of the hearing device2that faces the opening of the ear (capturing the environment).

The hearing device2or the processor14is configured to predict an output response based on the external input signal9and the gain settings. The hearing device2or the processor14may be configured to predict an output response based on the external input signal9, the output signal15and the gain settings. The hearing device2or the processor14is configured to determine a difference between the predicted output response and ear canal microphone input signal11B.

In one or more exemplary hearing devices, the processing unit13is configured to predict an output response based on the external input signal9and gain settings of the hearing device and to determine a difference between the predicted output response and the ear canal microphone input signal11B.

In one or more exemplary hearing devices, determining a difference between the predicted output response and the ear canal microphone input signal11B comprises comparing the external input signal9received at the external microphone8and the ear canal microphone input signal11B from the ear canal microphone10. The hearing device2may be configured to determine the difference between the predicted output response and the ear canal microphone input signal11B by estimating an ear parameter such as the ear canal length. As a length resonance results in a spectral notch in the output response at the ear canal microphone10, and the frequency of this notch varies with the residual ear canal length, the hearing device2determines the ear canal length based on identification of the frequency of the notch and categorization of the frequency. Once the frequency of the notch of the output response at the ear canal microphone is identified, a canal length that is expected to result in a notch at this frequency is determined using the category. The hearing device2may determine an appropriate real-ear insertion gain (REIG) correction for the ear canal based on an expected spectral difference between the locations of the ear canal microphone8and the tympanic membrane. To correct the insertion gain, the hearing device2may be configured to apply the inverse of the predicted real-ear insertion gain, such as applying half of the predicted real-ear insertion gain.

The hearing device2may be configured to categorize an ear canal. The hearing device2may be configured to determine one or more ear canal parameters, such as one or more of an ear canal volume, an ear canal width, an ear canal length, and an ear canal conicity.

The hearing device2may be configured to determine one or more ear canal parameters based on an estimate of real-ear unaided gain, and/or user input.

The external microphone8may be configured to obtain the external input signal by determining one or more characteristics of the external input signal, such as in one or more frequency bands.

The ear canal microphone10may be configured to obtain the ear microphone input signal by determining one or more characteristics of ear canal microphone input signal, such as by measuring the ear canal microphone input signal indicative of the output signal as received by the ear canal microphone. For example, measuring the ear canal microphone input signal may comprise determining a forward pressure level of the ear canal microphone input signal.

FIG.2is a cross-section of a user's ear having an exemplary hearing device2A partly inserted in the ear canal20of the ear according to the disclosure. The hearing device2A is an in-the-ear hearing device. The hearing device2A comprises a housing6, a receiver16A, an external microphone8A for obtaining an input signal and an ear canal microphone10A. The receiver16A is placed in an ear canal part of the hearing device2A, and thereby called an ear canal receiver16A. The hearing device2A comprises the ear canal microphone10A and the ear canal receiver16A, which are placed facing the ear drum or tympanic membrane22. The hearing device2A comprises a processor14A configured to compensate for a hearing loss of a user. The receiver16A is configured to transmit an output signal to be directed towards an eardrum of the hearing device user. The ear canal microphone10A is configured to obtain an ear canal microphone input signal11B based on the output signal received from the receiver16A because the ear canal microphone10A receives the output signal from the receiver16A as an ear canal microphone input signal. The output signal received as input at the ear canal microphone10A is affected by the ear canal properties. The processor14A is configured to estimate the ear geometry based on the external input signal and the ear canal microphone input signal by e.g.: predicting an output response based on the external microphone input signal and gain settings, determining a difference between the predicted output response and the ear canal microphone input signal, and estimating the ear geometry based on the difference. In one or more exemplary hearing devices, determining a difference between the predicted output response and the ear canal microphone input signal comprises comparing the input signal received at the external microphone and the ear canal microphone input signal at the ear canal microphone.

FIG.3shows a flow diagram of an exemplary method of estimating an ear geometry of an ear of a hearing device user with a hearing device. The hearing device comprises an ear canal microphone, an external microphone and a receiver. The method comprises obtaining102an external input signal with the external microphone, such as using the external microphone.

In one or more methods, obtaining102an external input signal with the external microphone comprises measuring102athe external input signal using the external microphone, e.g. using the external microphone and analysing the external input signal.

The method100comprises transmitting104an output signal with the receiver and obtaining105an ear canal microphone input signal using the ear canal microphone. In one or more exemplary methods, ear canal microphone input signal may be a specific measurement signal and/or an environmental signal.

The method100comprises estimating106an ear geometry based on the external input signal and the ear canal microphone input signal.

In one or more exemplary methods, estimating106an ear geometry comprises predicting106aan output response based on the external input signal and the gain settings of the hearing device, and/or optionally device calibration (such as factory or default device calibration). Estimating106an ear geometry may comprise determining106ba difference between the predicted output response and the ear canal microphone input signal, and estimating106cthe ear geometry based on the difference.

In one or more exemplary methods, estimating106an ear geometry comprises categorizing106dan ear canal. For example, one or more categories may be predetermined. A plurality of categories may lead to more accuracy in estimating the ear geometry. Categorizing an ear may be performed based on the ear canal parameter. It may also be seen that categorizing an ear comprises estimating the ear geometry.

In one or more exemplary methods, estimating106the ear geometry comprises determining106ean ear canal parameter. The ear canal parameter may comprise one or more of an ear canal volume, an ear canal width, an ear canal length, and an ear canal conicity.

In one or more exemplary methods, determining106ethe ear canal parameter is based on an estimate of real-ear unaided gain, user input and/or acoustic measurement. In determining the difference between the predicted output response and the measured ear canal microphone input signal, the inventors have determined that a length resonance often results in a spectral notch in the output response at the ear canal microphone, and the frequency of this notch varies with the residual ear canal length. The ear canal length can thereby be determined. Once the frequency of the notch of the output response at the ear canal microphone is identified, a canal length that is expected to result in a notch at this frequency is determined using the category. An appropriate real-ear insertion gain (REIG) correction for this ear canal may be determined based on an expected spectral difference between the locations of the ear canal microphone and the tympanic membrane. To correct the insertion gain, the method may comprise applying the inverse of the predicted real-ear insertion gain (assuming target gain is 0 dB). Because predictions may not be perfect, a fraction of the predicted real-ear insertion gain may be used as a conservative correction. If the target gain is not a flat (e.g. 0 dB at all frequencies), the target gain may be subtracted from the predicted gain before using it as a correction factor.

In one or more exemplary methods, determining106ba difference between the predicted output response and the ear canal microphone input signal comprises determining a difference between the predicted output magnitude spectrum and the measured output magnitude spectrum. Predicting106athe output response may be performed using the output signal as transmitted by the receiver.

In one or more exemplary methods, determining106ba difference between the predicted output response and the ear canal microphone input signal comprises comparing the external input signal received at the external microphone and the ear canal microphone input signal at the ear canal microphone. If the receiver and the ear canal microphone responses are known, the natural resonance of the open ear canal or the effect of occluding the ear can be accounted for. Alternatively, or additionally, the ear canal microphone response can be assumed as flat and the receiver response can be assumed as approximating the open ear response. With the disclosed method, the measured transducer response (receiver to ear canal microphone) may approximate the real ear unaided response (REUR).

In one or more exemplary methods, determining106bthe difference may comprise determining an insertion gain by comparing the signals at the external microphone and at the ear canal microphone, and subtracting the measured transducer response (receiver to ear canal microphone).

In one or more exemplary methods, obtaining102the external input signal comprises determining102bone or more characteristics of the external input signal, such as in one or more frequency bands. For example, a characteristic may comprise a distortion and/or a spectrum, such as an amplitude (e.g. maximum amplitude) and/or a phase.

In one or more exemplary methods, obtaining105the ear canal microphone input signal comprises determining a forward pressure level of the ear canal microphone input signal. Sound pressure measured by an ear canal microphone can be decomposed into forward pressure level and reflected pressure level. The present disclosure relates to determining the forward pressure level of the ear canal microphone input signal.

In one or more exemplary methods, determining106bthe difference between the predicted output response and the ear canal microphone input signal is based on one or more hearing device configuration parameters.

In one or more exemplary methods, determining106bthe difference between the predicted output response and the ear canal microphone input signal is based on an initial hearing device calibration setting.

In one or more exemplary methods, determining106bthe difference between the predicted output response and the ear canal microphone input signal is based on one or more algorithm parameters. For example, the one or more algorithm parameters may be indicative of characteristics of the algorithm, such as interaction of spectral bands, non-linearity.

In one or more exemplary methods, determining106bthe difference between the predicted output response and the ear canal microphone input signal may comprise estimating other parameters of the ear canal, such as one or more tympanic membrane properties. Determining the difference between the predicted output response and the measured ear canal microphone input signal may take into account ear canal dimensions (e.g. user-supplied information about ear canal geometry (e.g., large/small, male/female, head circumference, etc.)) and/or hearing device configurations. Predicting ear canal dimensions may be performed based on acoustic measurements according to this disclosure.

In one or more exemplary methods, predicting106athe output response is based on the initial hearing device calibration setting.

In one or more exemplary methods, obtaining102the external input signal comprises obtaining a specific measurement signal from an external device.

The use of the terms “first”, “second”, “third” and “fourth”, etc. does not imply any order, but are included to identify individual elements. Moreover, the use of the terms first, second, etc. does not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Note that the words first and second are used here and elsewhere for labelling purposes only and are not intended to denote any specific spatial or temporal ordering. Furthermore, the labelling of a first element does not imply the presence of a second element and vice versa.

LIST OF REFERENCES

2hearing device2A hearing device seen from a cross-section3transceiver input signal4antenna5first wireless input signal6housing7radio transceiver8external microphone8A external microphone9external input signal from external microphone10ear canal microphone10A ear canal microphone11audio output signal emitted by the receiver11A audio signal received as input at the ear canal microphone11B ear canal microphone input signal12controller13processing unit14processor14A processor15output signal16receiver16A ear canal receiver18audio signal obtained at the external microphone20ear canal22ear drum or tympanic membrane100method of estimating ear geometry102obtaining an external input signal102ameasuring the external input signal102bdetermining one or more characteristics of the external input signal104transmitting an output signal with the receiver and measuring105the output signal using the ear canal microphone105obtaining the ear canal microphone signal using the ear canal microphone106estimating the ear geometry106apredicting an output response based on gain settings106bdetermining a difference between the predicted output response and the ear canal microphone input signal106cestimating an ear geometry based on the difference106dcategorizing an ear106edetermining an ear canal parameter