DK201470370A1 - Apparatus for testing directionality in hearing instruments - Google Patents
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Abstract
An apparatus for testing a directional hearing instrument includes: a first microphone for coupling with an output of the hearing instrument, wherein the first microphone is configured to receive an audio output signal from the hearing instrument; a first speaker for transmission of a first signal having a first frequency component at a first frequency; a second speaker for transmission of a second signal having a second frequency component at a second frequency; and a processing unit configured to determine one or more hearing instrument parameters based on cross spectrum analysis of the first signal and the audio output signal.
Description
APPARATUS FOR TESTING DIRECTIONALITY IN HEARING INSTRUMENTSFIELD
The present disclosure relates to apparatus fortesting a hearing instrument andmethod related thereto and in particular to an apparatus for testing directionality of ahearing instrument.
BACKGROUND
Many modern hearing instruments include signal processing which allows the hearinginstrument to amplify the sound arriving from one direction (typically from the front ofthe hearing instrument user), while attenuating the sound from other directions. Asimple test to verify this functionality will present pure tones at various frequencies,from the front of the hearing instrument and from another direction, in two separatemeasurements.
This type of test will work well if the hearing instrument is working in a simple modewhere the amplification is nearly independent of the type of signals presented to its microphone(s).
However, with the recent development of advanced hearing instruments, the signalprocessing functions in the hearing instrument may include adaptation to the receivedsignal. Specifically, one type of algorithm may detect the presence or absence ofspeech in the microphone signai(s), and process the signai(s) in order to optimizespeech perception for the hearing instrument user. Such an algorithm may classifypure tone signals as non-speech or noise and suppress the signals, leading to anincorrect measurement of the directionality characteristics.
Attempts to avoid the suppression of the directionality test signal have been describedin the literature, e.g. by presenting simultaneous tones over a broad spectrum, somehearing instrument algorithms are more likely to detect the test signal as "speech” andthereby allow for a test of directionality.
Although this method may be effective in some situations, the trend towards moreadvanced speech processing algorithms in hearing instruments leads to a desire to use natural signals as stimuli.
SUMMARY
There is a need for an apparatus and method for testing directionality of a hearinginstrument using natural signals, such as speech, traffic noise, cocktail party noise etc.
Furthermore, it is desirable to be able to present signals from more directions of thehearing instrument simultaneously to allow the hearing instrument algorithms toperform as intended.
Accordingly, an apparatus for testing a directional hearing instrument is provided. Theapparatus comprises: a first microphone for coupling with an output of the hearinginstrument; a first speaker for transmission of a first signal; and a second speaker fortransmission of a second signal. The apparatus is configured to: transmit the firstsignal, the first signal having a first frequency component at a first frequency; transmitthe second signal, the second signal having a second frequency component at asecond frequency; receive an audio output signal from the hearing instrument; anddetermine one or more hearing instrument parameters based on cross spectrumanalysis of the first signal and the audio output signal.
Also disclosed is a method fortesting a directional hearing instrument. The methodcomprises: transmitting a first signal through a first speaker, the first signal having afirst frequency component at a first frequency; transmitting a second signal through asecond speaker the second signal having a second frequency component at a secondfrequency; receiving an audio output signal from the hearing instrument; anddetermining one or more hearing instrument parameters based on cross spectrumanalysis of the first signal and the audio output signal.
It is an advantage that it provides a high degree of freedom in the choice oftestsignals, i.e. the first signal and the second signal (e.g. front and back). Hence, inaccordance with some embodiments described herein, test signals resembiing real lifesituations may be chosen, and any suppression of artificial test signals may beavoided, and the directionality of the hearing instrument may be tested in situations aswill be experienced by the end user.
The method for testing a directional hearing instrument may be incorporated in theapparatus as also disclosed. Furthermore any elements or procedural steps asdescribed in connection with any one aspect may be used with any other aspects orembodiments, mutatis mutandis.
An apparatus for testing a directional hearing instrument includes: a first microphonefor coupling with an output of the hearing instrument, wherein the first microphone isconfigured to receive an audio output signal from the hearing instrument; a firstspeaker for transmission of a first signal having a first frequency component at a firstfrequency; a second speaker for transmission of a second signal having a second frequency component at a second frequency; and a processing unit configured todetermine one or more hearing instrument parameters based on cross spectrumanalysis of the first signal and the audio output signal.
Optionally, the processing unit is configured to determine the one or more hearinginstrument parameters also based on cross spectrum analysis of the second signal andthe audio output signal.
Optionally, a difference between the first frequency and the second frequency is lessthan 10 Hz.
Optionally, the one or more hearing instrument parameters comprise a first hearinginstrument parameter, the first hearing instrument parameter being a front-to-backratio.
Optionally, a ratio or a difference between the first frequency component and thesecond frequency component is anywhere from 0.2 to 5.
Optionally, the one or more hearing instrument parameters comprise a first transferfunction that is based on the first signal and the audio output signal.
Optionally, the one or more hearing instrument parameters comprise a second transferfunction that is based on the second signal and the audio output signal.
Optionally, the processing unit is configured to perform a dual channel DFT of the firstsignal and the audio output signal and/or of the second signal and the audio outputsignal.
Optionally, the first signal and the second signal are at least partly separate in time.
Optionally, the first signal comprises an international Speech Test Signal.
A method for testing a directional hearing instrument includes: transmitting a first signalthrough a first speaker, the first signal having a first frequency component at a firstfrequency; transmitting a second signal through a second speaker, the second signalhaving a second frequency component at a second frequency; receiving an audiooutput signal from the hearing instrument; and determining one or more hearinginstrument parameters based on cross spectrum analysis of the first signal and theaudio output signal.
Optionally, the one or more hearing instrument parameters are determined also basedon cross spectrum analysis of the second signal and the audio output signal
Optionally, a difference between the first frequency and the second frequency is lessthan 10 Hz.
Optionally, the one or more hearing instrument parameters comprise a first hearinginstrument parameter, the first hearing instrument parameter being a front-to-backratio.
Optionaliy, the front-to-back ratio is based on a first transfer function and a secondtransfer function, wherein the first transfer function is based on the first signal and theaudio output signal, and the second transfer function is based on the second signal andthe audio output signal.
Other and further aspects and features will be evident from reading the followingdetailed description,
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and advantages wiii become readily apparent to thoseskilled in the art by the following detailed description of exemplary embodimentsthereof with reference to the attached drawings, in which:
Fig. 1 schematically illustrates an exemplary apparatus for testing a directionalhearing instrument,
Fig. 2 schematically illustrates an exemplary processing unit for an exemplaryapparatus for testing a directional hearing instrument,
Fig. 3 shows a flow diagram of an exemplary method for testing a directional hearinginstrument,
Fig. 4 shows an illustrative example of determining the first cross spectrum function,
Fig. 5 shows an example of power spectrums of an exemplary first signal and anexemplary second signal,
Fig. 6 shows an example of exemplary hearing instrument parameters obtained fromtesting a hearing instrument operating in an omni-directional mode, and
Fig. 7 shows an example of exemplary hearing instrument parameters obtained fromtesting a hearing instrument operating in a directional mode.
DETAILED DESCRIPTION
Various features are described hereinafter with reference to the figures. It should benoted that the figures may or may not be drawn to scale and that the elements ofsimilar structures or functions are represented by like reference numerals throughoutthe figures. It should be noted that the figures are only intended to facilitate thedescription of the features. They are not intended as an exhaustive description of theclaimed invention or as a limitation on the scope of the claimed invention. In addition,an illustrated feature needs not have all the aspects or advantages shown. An aspector an advantage described in conjunction with a particular feature is not necessarilylimited to that feature and can be practiced in any other features even if not soillustrated or if not so explicitly described.
The first signal may be directed towards a first input transducer of the hearinginstrument, such as a front input transducer of the hearing instrument. The secondsignal may be directed towards a second input transducer of the hearing instrument,such as a rear input transducer of the hearing instrument. The first speaker may beconfigured for transmitting the first signal towards the first input transducer of thehearing instrument, such as the front input transducer of the hearing instrument. Thesecond speaker may be configured for transmitting the second signal towards thesecond input transducer of the hearing instrument, such as the rear input transducer ofthe hearing instrument.
The first signal and/or the second signal may be a speech signal. The first signal and/orthe second signal may be a speech signal in a language such as English, Danish,German, French, Arabic, Chinese, Japanese, Spanish. The first signal and/or thesecond signal may be the International Speech Test Signal (ISTS). ISTS is aninternationally recognized test signal based on natural recordings of speech. The ISTSreflects a female speaker for six different mother tongues (American English, Arabic,Chinese, French, German, and Spanish).
The first signal and/or the second signal may be a noise signal. The first signal and/orthe second signal may be a random noise signal. The first signal and/or the secondsignal may be a random noise signal with a characteristic power spectrum, e.g. flat,decaying, increasing, and/or variable over a range of frequencies. For example, thefirst signal and/or the second signal may be white noise, pink noise, Brownian noise,blue noise, violet noise, grey noise.
The first and/or the second signal may be a natural sounding noise signal, e.g. a mix ofother speech signals, traffic noise. The first signal and/or the second signal may be a noise signal comprising a plurality of speech signals, e.g. the first signal and/or thesecond signal may be cocktail party noise and/or a babbie noise.
In an exemplary apparatus and/or method, the first signal is a speech signal, e.g. theISTS, and the second signal is a noise signal, e.g. a random noise signal and/or anatural sounding noise signal.
Transmission of the second signal, or transmission of a second part of the secondsignal, may be simultaneous with transmission of the first signal, or transmission of afirst part of the first signal. Simultaneous transmission of the first signal and the secondsignal may decrease test time and/or increase quality of the test since the hearinginstrument is subjected to a situation resembling a real life situation. Accordingly, thefirst and second signal may have an overlap in time. For example, the first signal andthe second signal may overlap in one or more overlap periods. An overlap period, e.g.a first overlap period, may have a duration of at least 2 seconds.
The first microphone may be a directional microphone. The first microphone may beshielded to avoid receiving sound transmitted from the first and/or second speakers.The coupling of the first microphone with the output of the hearing instrument may beobtained by providing an acoustic tube between the first microphone and the output ofthe hearing instrument. Provision of an acoustic tube between the output of the hearinginstrument and the first microphone may avoid or decrease reception of soundtransmitted from the first speaker and/or second speaker.
The apparatus may be configured to perform a cross spectrum analysis of the firstsignal and the audio output signal. The apparatus may be configured to perform across spectrum analysis of the second signal and the audio output signal.
Determining one or more hearing instrument parameters may be based on crossspectrum analysis of the second signal and the audio output signal. Determining one ormore hearing instrument parameters may be based on cross spectrum analysis of thefirst signal and the audio output signal and cross spectrum analysis of the secondsignal and the audio output signal.
The apparatus may be configured to determine one or more hearing instrumentparameters based on cross spectrum analysis of the second signal and the audiooutput signal. The apparatus may be configured to determine one or more hearinginstrument parameters based on cross spectrum analysis of the first signal and the audio output signal and cross spectrum analysis of the second signal and the audiooutput signal.
The apparatus may be configured to obtain a power spectrum of the first signal and/orthe second signal and/or the audio output signal. The apparatus may be configured toobtain a cross spectrum of the first signal and the audio output signai. The apparatusmay be configured to obtain a cross spectrum of the second signal and the audiooutput signal.
Power spectrum and/or cross spectrum of a signal, such as the first signai and/or thesecond signal and/or the audio output signal and/or any combinations hereof, may beobtained by cross spectrum analysis.
The first signal has a first frequency component at a first frequency, and the secondsignal has a second frequency component at a second frequency. The differencebetween the first frequency and the second frequency may be less than 10 Hz, such asless than 5 Hz, such as less than 1 Hz, The first signal and the second signal may haveoverlapping frequency components, such as the first frequency component and thesecond frequency component. The first frequency and the second frequency may bethe same frequency, or substantially the same frequency.
The frequency components, such as the first frequency component and/or the secondfrequency component, may have a certain magnitude. The frequency components,such as the first frequency component and/or the second frequency component, mayhave a certain magnitude relative to each other. The magnitude of the frequencycomponents may be measured in units of decibel sound pressure ievel (dBSPL). Arelationship, such as a ratio and/or a difference, between the first frequencycomponent, e.g. measured in dBSPL, and the second frequency component, e.g.measured in dBSPL, may be in the range from 0.2 to 5.
The one or more hearing instrument parameters may comprise a first hearinginstrument parameter and/or a second hearing instrument parameter and/or a thirdhearing instrument parameter. The one or more hearing instrument parameters maycomprise a plurality of hearing instrument parameters comprising the first hearinginstrument parameter and/or the second hearing instrument parameter and/or the thirdhearing instrument parameter.
The one or more hearing instrument parameters may comprise a first transfer function.The first transfer function may be based on the first signal and the audio output signai.
The first hearing instrument parameter and/or the second hearing instrumentparameter and/or the third hearing instrument parameter may be the first transferfunction. The first transfer function may be a front-to-output transfer function of thehearing instrument. A front-to-output frequency response of the hearing instrument maybe obtained based on the first transfer function.
The one or more hearing instrument parameters may comprise a second transferfunction. The second transfer function may be based on the second signal and theaudio output signal.
The first hearing instrument parameter and/or the second hearing instrumentparameter and/or the third hearing instrument parameter may be the second transferfunction. The second transfer function may be a rear-to-output transfer function of thehearing instrument. A rear-to-output frequency response of the hearing instrument maybe obtained based on the second transfer function.
The first transfer function and/or second transfer function may be obtained using duaichannel DFT, such as duai channel FFT analysis. Duai channel DFT comprises crossspectrum analysis. The first transfer function may be obtained using duai channel DFTof the first signal and the audio output signal. The second transfer function may beobtained using dual channel DFT of the second signal and the audio output signal· Theapparatus may be configured to perform a dual channei DFT of the first signai and theaudio output signal. Additionally or alternatively, the apparatus may be configured toperform a dual channei DFT of the second signal and the audio output signal.
The one or more hearing instrument parameters may comprise a front-to-back ratio.The front-to-back ratio may be based on the first transfer function and the secondtransfer function. The front-to-back ratio may be based on the first transfer function andthe second transfer function, wherein the first transfer function may be based on thefirst signai and the audio output signai and the second transfer function may be basedon the second signai and the audio output signal· The front-to-back ratio may be a ratioof the first transfer function and the second transfer function.
The first hearing instrument parameter and/or the second hearing instrumentparameter and/or the third hearing instrument parameter may be the front-to-back ratio.
The first signal and the second signai may be at feast partly separate in time. The firstsignal and the second signai may have one or more instances during transmissionwhere they are indistinguishable. However, over time the first signal and the second signal are distinguishable, i.e. the first signal and the second signal has one or moreinstances during transmission where they are distinguishable.
The first signal and the second signal may be very different, e.g. in contents offrequency components and/or time variation. For example, the cross correlation (timelag =0) between the first signal and the second signal may be less than a firstthreshold. Thus, determining of one or more hearing instrument parameters may beperformed with short test signals and/or short test time.
The first signal and the second signal may be very similar, e.g. less different, e.g. incontents of frequency components and/or time variation. For example, the crosscorrelation (time lag =0) between the first signal and the second signal may be largerthan a second threshold. Similarity of the first signal and the second signal may followfrom using natural signals. However, the first signal and the second signal may bedifferent in at least a plurality of instances during the test duration, such as thecomplete duration of the first signal and/or second signal. For example, the first signalmay be a speech signal and the second signal may be a noise signal, e.g. a noisesignal comprising a piuraiity of speech signals.
The first signal may be a finite signal with a first duration. The second signal may be afinite signal with a second duration. The first duration and/or the second duration maybe between 1-30 seconds, such as between 5-20 seconds, such as between 10-15seconds. The first duration and the second duration may be the same, or substantiallythe same. The first duration and the second duration may differ by less than 3 second,such as less than 2 seconds, such as less than 1 second.
Cross spectrum analysis of the first signal and the audio output signal and/or crossspectrum analysis of the second signal and the audio output signal may comprisesegmenting the first signal and/or the second signal and/or the audio output signal in aplurality of segments. The segments, e.g. each of the piuraiity of the segments or agroup of segments may have durations between 10-400 ms, such as between 30-300ms, such as between 50-200 ms, such as between 70-150 ms. The segments, e.g.each of the plurality of the segments or a group of segments, may have the sameduration.
Cross spectrum analysis of the first signal and the audio output signal and/or crossspectrum analysis of the second signal and the audio output signal may compriseaveraging over cross spectrum analysis of a plurality of segments of the first signaland/or the second signal and/or the audio output signal.
Fig. 1 schematically illustrates an exemplary apparatus 50 fortesting a directionalhearing instrument 2. The apparatus 50 comprises: a first microphone 52 for couplingwith an output 4 of the hearing instrument 2; a first speaker 54 for transmission of a firstsignal 56; and a second speaker 58 for transmission of a second signal 60.
A directional hearing instrument, such as the directional hearing instrument 2 asillustrated, comprises a first input transducer 6, a second input transducer 8, an output4, and a hearing instrument processing unit 10. The first input transducer 6 and thesecond input transducer 8 is typically positioned to primarily detect acoustic signalsfrom opposite or approximately opposite directions. For example, the first inputtransducer 6 may be a front input transducer, and the second input transducer 8 maybe a rear input transducer. The directional hearing instrument 2 furthermore comprisesa hearing instrument housing 12. The first input transducer 6, the second inputtransducer 8, the output 4, and the hearing instrument processing unit 10 are containedin the hearing instrument housing 12.
The first speaker 54 transmits the first signal 56 towards the first input transducer 6 ofthe hearing instrument 2. The second speaker 58 transmits the second signal 60towards the second input transducer 8 of the hearing instrument 2. The first inputtransducer 6 may detect the second signal 60, or a fraction of the second signal 60.
The second input transducer 8 may detect the first signal 56, or a fraction of the firstsignal 56.
The apparatus 50 is configured to: transmit the first signal 56, transmit the secondsignal 60, and receive an audio output signal 5 from the hearing instrument 2. The firstsignal 56 and the second signal 60 are acoustic signals. The first signal has a firstfrequency component at a first frequency, and the second signal has a secondfrequency component at a second frequency. The first frequency and the secondfrequency may be the same and/or overlapping, e.g. the difference between the firstfrequency and the second frequency may be less than 10 Fiz. The first signal 56 andthe second signal 60 may comprise contents at one or more common frequencies. Arelationship, such as a ratio or difference, between the first frequency component andthe second frequency component measured in sound pressure, such as dBSPL, maybe in the range from 0.1 to 20, such as in the range from 0.1 to 10, such as in therange from 0.2 to 5.
The apparatus 50 may transmit the first signal 56 from the first speaker 54simultaneously, or within less than 5 ms, such as within less than 1 ms, of transmitting the second signal 60 from the second speaker 58. The first signal 56 and the secondsigna! 60 may be different over time. For example, the first signal 56 and the secondsignal 60 may have one or more instances during transmission where they areindistinguishable, but over time they are distinguishable, i.e. the first signal 56 and thesecond signal 60 has one or more instances during transmission where they aredistinguishable.
The apparatus 50 is furthermore configured to determine one or more hearinginstrument parameters based on cross spectrum analysis of the first signal 56 and theaudio output signal 5. The apparatus 50 may furthermore be configured to determineone or more hearing instrument parameters based on cross spectrum analysis of thesecond signal 60 and the audio output signal 5.
The apparatus 50 furthermore comprises an apparatus processing unit 64. Theapparatus processing unit 64 is connected to the first microphone 52, the first speaker54, and the second speaker 58. The apparatus processing unit 64 receives, from thefirst microphone 52 an input signal 66 indicative of the audio output signal 5 of thehearing instrument 2.
The apparatus processing unit 64 may be configured to determine the one or morehearing instrument parameters. Furthermore, the apparatus processing unit 64 may beconfigured to control the first speaker 54 to transmit the first signal 56 by transmitting afirst speaker signal 68 indicative of the first signal 56, and/or the apparatus processingunit 64 may be configured to control the second speaker 58 to transmit the secondsignal 60 by transmitting a second speaker signal 70 indicative of the second signal 60.
The one or more hearing instrument parameters may comprise a first transfer functionbased on the first signal 56 and the audio output signal 5. The first transfer functionmay be based on cross spectrum analysis of the first signal 56 and the audio output signal 5.
The one or more hearing instrument parameters may comprise a second transferfunction based on the second signal 60 and the audio output signal 5. The secondtransfer function may be based on cross spectrum analysis of the second signal 60 andthe audio output signal 5.
The one or more hearing instrument parameters may be a front-to-back ratio(sometimes also referred to as a front-to-rear ratio), e.g. a ratio of the first signal 56 andthe second signal 60 in the received audio output signal 5. The front-to-back ratio may be determined from a ratio of a cross spectrum analysis of the first signal 56 and theaudio output signal 5 and a cross spectrum analysis of the second signal 60 and theaudio output signal 5. The front-to-back ratio may be determined by a ratio between thefirst transfer function and the second transfer function.
The apparatus 50 comprises an apparatus housing 62. The housing 62 comprise thefirst microphone 52, the first speaker 54, and the second speaker 58. in the apparatus50, as depicted, the apparatus housing comprises the processing unit 64. In otherexemplary apparatuses (not shown), the processing unit 64 may be external to theapparatus housing 62, e.g. the processing unit 64 may be a processing unit of a laptop,a smartphone, a tablet computer, or any other device.
The apparatus 50 further comprises an optional interface 72 for providing an output toa user or an additional device. The interface 72 may be a display, a wireless transmitterunit, an interface speaker, and/or a connector. The wireless transmitter may be aBluetooth transmitter, a WiFi transmitter, a 3G transmitter, and/or a 4G transmitter. Theconnector may be a USB connector, a FireWire connector, and/or a custom connector.The interface 72 may connect the apparatus to an external device, such as a laptop, asmart phone, a tablet computer, and/or a PC.
Fig. 2 schematically illustrates an exemplary processing unit 64 for an exemplaryapparatus 50 for testing a directional hearing instrument 2. The processing unit 64comprises: a first tone generator 74, a second tone generator 76, a first cross spectrumanalyzer 78, and a second cross spectrum analyzer 80. The first tone generator 74provides the first speaker signal 68 indicative of the first signal 56 to the first speaker54 and the first cross spectrum analyzer 78, The second tone generator 76 providesthe second speaker signal 70 indicative of the second signal 60 to the second speaker58 and the second cross spectrum analyzer 80. The first cross spectrum analyzer 78and the second cross spectrum analyzer 80 furthermore receive the input signal 66indicative of the audio output signal 5.
The first cross spectrum analyzer 78 determines one or more hearing instrumentparameters based on cross spectrum analysis of the first signal 56 and the audiooutput signal 5. The cross spectrum analysis of the first signal 56 and the audio outputsignal 5 may be based on the first speaker signal 68 indicative of the first signal 56 andthe input signal 66 indicative of the audio output signal 5. The first cross spectrumanalyzer 78 provides a first analyzer output 82 comprising the determined one or more hearing instrument parameters, such as a first transfer function or a first crossspectrum function of the first signai 56 and the audio output signal 5.
The second cross spectrum analyzer 80 determines one or more hearing instrumentparameters based on cross spectrum analysis of the second signal 60 and the audiooutput signal 5. The cross spectrum analysis of the second signal 60 and the audiooutput signal 5 may be based on the second speaker signal 70 indicative of the secondsignal 60 and the input signal 66 indicative of the audio output signal 5. The secondcross spectrum analyzer 80 provides a second analyzer output 84 comprising thedetermined one or more hearing instrument parameters, such as a second transferfunction or a second cross spectrum function of the second signal 56 and the audiooutput signal 5.
The first analyzer output 82 and the second analyzer output 84 may be provided to theinterface 72 and/or a second processing unit. The first analyzer output 82 and thesecond analyzer output 84 may be combined to form a processing unit output, i.e. thefirst analyzer output 82 and the second analyzer output 84 may be combined todetermine a front-to-back ratio of the hearing instrument 2. Alternatively and/oradditionally, the first analyzer output 82 and the second analyzer output 84 may beprovided individually.
Fig. 3 shows a flow diagram of an exemplary method 100 for testing a directionalhearing instrument 2. The method comprises: transmitting 102 a first signal 56 througha first speaker 54; transmitting 104 a second signal 60 through a second speaker;receiving 106 an audio output signal 5 from the hearing instrument 2; and determining108 one or more hearing instrument parameters based on the first signal 56 and theaudio output signai 5.
The first signai 56 has a first frequency component at a first frequency. The secondsignal 60 has a second frequency component at a second frequency. The firstfrequency and the second frequency may be substantially the same frequency and/orthe difference between the first frequency and the second frequency may be less than10 Hz, such as less than 5 Hz, such as less than 2 Hz.
Determining 108 one or more hearing instrument parameters is based on crossspectrum analysis of the first signal 56 and the audio output signai 5. Additionally,determining 108 one or more hearing instrument parameters may be based on crossspectrum analysis of the second signal 60 and the audio output signal 5.
Transmitting 102 the first signal 56 and transmitting 104 the second signal 60 may beinterchanged and/or performed simultaneously. Transmitting 102 the first signal 56 andtransmitting 104 the second signal 60 may be performed simultaneously to resemble anatural occurring situation e.g. a situation comprising speech from a front direction andnoise from a rear direction.
The one or more hearing instrument parameters may comprise a first hearinginstrument parameter. The first hearing instrument parameter may be a function offrequency. The first hearing instrument parameter may be a front-to-back ratio, e.g. aratio of the first signal 56 and the second signal 60. The front-to-back ratio may bebased on a first transfer function and a second transfer function. The first transferfunction may be based on the first signal 56 and the audio output signal 5, e.g. basedon cross spectrum analysis of the first signal 56 and the audio output signal 5. Thesecond transfer function may be based on the second signal 60 and the audio outputsignal 5, e.g. based on cross spectrum analysis of the second signal 60 and the audiooutput signal 5.
The determining 108 of the one or more hearing instrument parameters, such as thefirst hearing instrument parameter, such as the front-to-back-ratio, may comprisedetermining the first transfer function based on cross spectrum analysis of the firstsignal 56 and the audio output signal 5, determining the second transfer function basedon cross spectrum analysis of the second signal 60 and the audio output signal 5, anddetermining a ratio of the first transfer function and the second transfer function.
The method 100, or parts of the method 100, may be impiemented in an apparatussuch as the apparatus 50 for testing a directiona! hearing instrument. Alternativelyand/or additionally the method 100, or parts of the method 100, may be implemented ina processing unit, such as the apparatus processing unit 64 of an apparatus 50 fortesting a directiona! hearing instrument 2. Alternatively and/or additionally, the method100, or part of the method 100, may be impiemented in software adapted to beexecuted in a processing unit, e.g. a processing unit of a persona! computer, a laptop,a smartphone, or a tablet computer. Particularly, the determining 108 of the one ormore hearing instrument parameters may be implemented in a processing unit and/orin software adapted to be executed in a processing unit.
One or more hearing instrument parameters may comprise a first transfer function,such as a first transfer function between the first signal and the audio output signal, asecond transfer function, such as a second transfer function between the second signal and the audio output signal, and/or a front-to-back ratio, such as a front-to-back ratiobetween the first transfer function and the second transfer function. Ail of thesefunctions may be a function of frequency (f).
In an exemplary method and/or apparatus, the first transfer function may bedetermined by: determining a first cross spectrum function (Gi,o(f)) between the first signal (Xi)and the audio output signal (y0) by cross spectrum analysis of the first signaland the audio output signal, determining a first power spectrum function (Gi,i(f)) of the first signal, and - determining the first transfer function (H^f)) of the first signal and the audiooutput signal based on the first cross spectrum function and the first powerspectrum function, e.g. a ratio of the first cross spectrum function and the firstpower spectrum function:
In an exemplary method and/or apparatus, the first signal (xi) may be a front signal,and/or the first transfer function may be a front-to-output frequency response for thehearing instrument.
The second transfer function may be determined by: - determining a second cross spectrum function (G2,0(f)) between the secondsignal (x2) and the audio output signal (y0) by cross spectrum analysis of thesecond signal and the audio output signal, - determining a second power spectrum function (G2,2(f)) of the second signal,and - determining the second transfer function (H2(f)) of the second signal and theaudio output signal based on the second cross spectrum function and thesecond power spectrum function, e.g. a ratio of the second cross spectrumfunction and the second power spectrum function:
in an exemplary method and/or apparatus, the second signal (x2) may be a rear signal,and/or the second transfer function may be a rear-to-output frequency response for thehearing instrument.
The front-to-back ratio (FB(f)) may be determined based on the first transfer functionand the second transfer function and/or based on the first and second cross spectrumsand the first and second power spectrums, e.g.:
Several algorithms may be used to compute one or more of Gi,i{f), Gio(f), Hi(f), G2,2(f),G2,o(f)> H2(f), For example, Welch’s method and/or Bartlett’s method may be used tocompute cross spectrum functions and/or power spectrum functions.
These methods determine cross spectrum functions and/or power spectrum functionsby averaging cross spectrum functions and/or power spectrum functions of shortsegments of the original signals. For example, calculation of the first cross spectrumfunction, the original signals are divided into short segments k, k-M,.... For eachsegment, a Fourier transform is performed for each signal, and the two Fouriertransforms representing segment k of the original signals are combined to obtain asegment cross spectrum for segment k:
Wherein X1ik(f) is the first Fourier transform of the kth segment of the first signal (xi). *denotes the complex conjugate. Hence, Y*0,k(f) is the complex conjugate of the outputFourier transform of the kih segment of the audio output signal (y0).
Gi,o is calculated by averaging the segment cross spectrums:
wherein n is the total number of segments. Similarly Gi,i(f), G2j2(f), G2,o(i) may befound:
where * denotes the complex conjugate.
Fig. 4 shows an iliusirative example of determining the first cross spectrum functionG-i.o from the first signal 200 and the second signal 201 The first signal 200 is dividedin a plurality of segments 202, 222, 242, e.g. corresponding to the segments k-1, k, andk+1 above.
To obtain the k-1 segment cross spectrum GiAk-i,the k-1 segment 202 of the firstsignal 200 is Fourier transformed 204 and multiplied 212 with the k-1 segment 206 ofthe second signal 201 being Fourier transformed 208 and complex conjugated 210.
To obtain the k segment cross spectrum Gi,0,k, the k segment 222 of the first signal 200is Fourier transformed 224 and multiplied 232 with the k segment 226 of the secondsignal 201 being Fourier transformed 228 and complex conjugated 230,
To obtain the k+1 segment cross spectrum Gio k-i, the k+1 segment 242 of the firstsignal 200 is Fourier transformed 244 and multiplied 252 with the k+1 segment 246 ofthe second signal 201 being Fourier transformed 248 and complex conjugated 250.
The resulting segment cross spectrums 214, 234, 254 may be averaged or weighted tofind the first cross spectrum function Gi,o.
The present method allows obtaining the transfer functions Hi(f) and H2(f) andfrequency responses for the hearing instrument, even in the presence of other signalswhich may act as a disturbance to the measurement procedure, such as the rearsignal, e.g. the second signal, in front-to-output calculations, and as the front signal,e.g. the first signal, in rear-to-output calculations.
In events of the first signal and the second signal being very different, e.g. in contentsof frequency components and/or time variation, a reliable estimate of the crossspectrum functions (Gi>2 and G2,i) may be obtained from a relatively short sample, i.e. afew number of segments. Conversely, in events of the first signal and the second signalbeing less different, e.g. in contents of frequency components and/or time variation, areliable estimate of the cross spectrum functions (Gi,2 and G2,i) may require a longersample, i.e. an increased number of segments.
The Fourier transformations above may be determined using discrete Fouriertransformation (DFT), such as the Fast Fourier Transformation (FFT).
Fig. 5 shows a simulated example of power spectra 300 of an exemplary first signal306 and an exemplary second signal 308. The power spectra 300 are shown in adiagram having a first logarithmic axis 302 with units of Hz, and a second axis 304 withunits of dB, In the exemplary power spectra 300 the first signal 306 being a speech signal and the second signal 308 is a noise signal. It is seen that the second signal 308comprises more power in higher frequencies than the first signal 306. Also seen is thatthe first signal 306 and the second signal 308 comprise overlapping frequencies. E.g.the power of the first signal 306 between 900 Hz and 1000 Hz is approximately similarto the power of the second signal 308 between 900 Hz and 1000 Hz.
Fig. 6 shows an example of exemplary hearing instrument parameters 400 obtainedfrom testing a hearing instrument operating in an omni-directiona! mode. Theexemplary hearing instrument parameters 400 are shown in a diagram having a firstlogarithmic axis 402 with units of Hz, and a second axis 404 with units of dB. The firsthearing instrument parameter 406 shows an obtained first transfer function, in thisexample a front-to-output frequency response for the hearing instrument. The secondhearing instrument parameter 408 shows an obtained second transfer function, in thisexample, a rear-to-output frequency response for the hearing instrument. It is seenthat, when operating in an omni-directional mode, the front-to-output frequencyresponse 406 and the rear-to-output frequency response 408 are substantiallyequivalent. Hence, the hearing instrument performs as intended in the omni-directionalmode.
Fig. 7 shows an example of exemplary hearing instrument parameters 500 obtainedfrom testing a hearing instrument operating in a directional mode. The exemplaryhearing instrument parameters 500 are shown in a diagram having a first logarithmicaxis 502 with units of Hz, and a second axis 504 with units of dB. The first hearinginstrument parameter 506 shows an obtained first transfer function, in this example afront-to-output frequency response for the hearing instrument. The second hearinginstrument parameter 508 shows an obtained second transfer function, in this example,a rear-to-ouiput frequency response for the hearing instrument, it is seen that, whenoperating in a directional mode, the front-to-output frequency response 506 and therear-to-output frequency response 508 differ substantially, and in particular they differcomparing with the results for the omni-directional mode as illustrated in Fig. 6. Hence,the hearing instrument performs as intended in the directional mode.
Although particular features have been shown and described, it will be understood thatthey are not intended to limit the claimed invention, and it will be made obvious to thoseskilled in the art that various changes and modifications may be made withoutdeparting from the spirit and scope of the claimed invention. The specification anddrawings are, accordingly to be regarded in an illustrative rather than restrictive sense.
The claimed invention is intended to cover ail alternatives, modifications andequivalents.
Apparatuses and methods are disclosed in the following items;
Item 1. An apparatus for testing a directional hearing instrument, the apparatuscomprising: - a first microphone for coupling with an output of the hearing instrument,wherein the first microphone is configured to receive an audio output signal from thehearing instrument, - a first speaker for transmission of a first signal, the first signal having afirst frequency component at a first frequency, - a second speaker for transmission of a second signal, the second signalhaving a second frequency component at a second frequency, and - a processing unit configured to determine one or more hearing instrumentparameters based on cross spectrum analysis of the first signal and the audio outputsignal.
Item 2. Apparatus according to item 1, wherein the processing unit is configured todetermine one or more hearing instrument parameters based on cross spectrumanalysis of the second signal and the audio output signal.
Item 3. Apparatus according to any of items 1-2, wherein the difference between thefirst frequency and the second frequency is less than 10 Hz.
Item 4. Apparatus according to any of the preceding items, wherein the one or morehearing instrument parameters comprises a first hearing instrument parameter being afront-to-back ratio.
Item 5. Apparatus according to any of the preceding items, wherein a relationshipbetween the first frequency component (dBSPL) and the second frequency component(dBSPL) is in the range from 0.2 to 5.
Item 6. Apparatus according to any of the preceding items, wherein the one or morehearing instrument parameters comprise a first transfer function based on the firstsignal and the audio output signal.
Item 7. Apparatus according to any of the preceding items, wherein the one or morehearing instrument parameters comprises a second transfer function based on thesecond signal and the audio output signal.
Item 8, Apparatus according to any of the preceding items, wherein the processingunit is configured to perform a dual channel DFT of the first signal and the audio outputsignal and/or of the second signal and the audio output signal.
Item 9. Apparatus according to any of the preceding items, wherein the first signaland the second signal are at least partly separate in time.
Item 10. Apparatus according to any of the preceding items, wherein the first signal isan International Speech Test Signal.
Item 11. Method for testing a directional hearing instrument, the method comprising: - transmitting a first signal through a first speaker the first signal having afirst frequency component at a first frequency; - transmitting a second signal through a second speaker the second signalhaving a second frequency component at a second frequency; - receiving an audio output signal from the hearing instrument; and - determining one or more hearing instrument parameters based on crossspectrum analysis of the first signal and the audio output signal.
Item 12. Method according to item 11, wherein determining one or more hearinginstrument parameters are based on cross spectrum analysis of the second signal andthe audio output signal item 13. Method according to any of items 11-12, wherein the difference between thefirst frequency and the second frequency is less than 10 Hz.
item 14. Method according to any of items 11-13, wherein the one or more hearinginstrument parameters comprises a first hearing instrument parameter being a front-to-back ratio.
Item 15. Method according to item 14, wherein the front-to-back ratio is based on afirst transfer function and a second transfer function, wherein the first transfer functionis based on the first signal and the audio output signal and the second transfer functionis based on the second signal and the audio output signal.
USTOF REFERENCES2 hearing instrument 4 output 5 audio output signal 6 first input transducer 8 second input transducer 10 hearing instrument processing unit 12 hearing instrument housing 50 apparatus 52 first microphone 54 first speaker 56 first signal 58 second speaker 60 second signal 62 apparatus housing 64 apparatus processing unit 66 input signal 68 first speaker signal 70 second speaker signal 72 interface 74 first tone generator 76 second tone generator 78 first cross spectrum analyzer 80 second cross spectrum analyzer 82 first analyzer output 84 second analyzer output 100 method for testing a directional hearing instrument 102 transmit first signal 104 transmit second signal 106 receive audio output signal 108 determine hearing instrument parameters
Claims (15)
1. An apparatus for testing a directional hearing instrument, comprising: a first microphone for coupling with an output of the hearing instrument, whereinthe first microphone is configured to receive an audio output signal from the hearinginstrument; a first speaker for transmission of a first signal having a first frequencycomponent at a first frequency; a second speaker for transmission of a second signal having a secondfrequency component at a second frequency; and a processing unit configured to determine one or more hearing instrumentparameters based on cross spectrum analysis of the first signal and the audio outputsignal.
2. The apparatus according to claim 1, wherein the processing unit is configuredto determine the one or more hearing instrument parameters also based on crossspectrum analysis of the second signal and the audio output signal.
3. The apparatus according to claim 1, wherein a difference between the firstfrequency and the second frequency is less than 10 Hz.
4. The apparatus according to claim 1, wherein the one or more hearinginstrument parameters comprise a first hearing instrument parameter, the first hearinginstrument parameter being a front-to-back ratio.
5. The apparatus according to claim 1, wherein a ratio or a difference between thefirst frequency component and the second frequency component is anywhere from 0.2to 5.
6. The apparatus according to claim 1, wherein the one or more hearinginstrument parameters comprise a first transfer function that is based on the first signaland the audio output signal.
7. The apparatus according to claim 6, wherein the one or more hearinginstrument parameters comprise a second transfer function that is based on the secondsignal and the audio output signal.
8. The apparatus according to claim 1, wherein the processing unit is configuredto perform a dual channel DFT of the first signal and the audio output signal and/or ofthe second signal and the audio output signal.
9. The apparatus according to claim 1, wherein the first signal and the secondsignal are at least partly separate in time.
10. The apparatus according to claim 1, wherein the first signal comprises aninternational Speech Test Signal.
11. A method for testing a directional hearing instrument, comprising:transmitting a first signal through a first speaker, the first signal having a first frequency component at a first frequency; transmitting a second signal through a second speaker, the second signalhaving a second frequency component at a second frequency; receiving an audio output signa! from the hearing instrument; anddetermining one or more hearing instrument parameters based on crossspectrum analysis of the first signal and the audio output signal.
12. The method according to claim 11, wherein the one or more hearing instrumentparameters are determined also based on cross spectrum analysis of the secondsigna! and the audio output signal
13. The method according to claim 11, wherein a difference between the firstfrequency and the second frequency is less than 10 Hz,
14. The method according to daim 11, wherein the one or more hearing instrumentparameters comprise a first hearing instrument parameter, the first hearing instrumentparameter being a front-to-back ratio.
15. The method according to ciaim 14, wherein the front-to-back ratio is based on afirst transfer function and a second transfer function, wherein the first transfer functionis based on the first signal and the audio output signal, and the second transferfunction is based on the second signal and the audio output signai.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DK201470370A DK201470370A1 (en) | 2014-06-20 | 2014-06-20 | Apparatus for testing directionality in hearing instruments |
| US14/311,974 US9729975B2 (en) | 2014-06-20 | 2014-06-23 | Apparatus for testing directionality in hearing instruments |
| JP2015121461A JP6282999B2 (en) | 2014-06-20 | 2015-06-16 | Device for testing the directivity of hearing aids |
| CN201510344608.0A CN105208503B (en) | 2014-06-20 | 2015-06-19 | Equipment for the directionality tested in hearing aid |
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| Application Number | Priority Date | Filing Date | Title |
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| DK201470370A DK201470370A1 (en) | 2014-06-20 | 2014-06-20 | Apparatus for testing directionality in hearing instruments |
| DK201470370 | 2014-06-20 |
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| DK201470370A1 true DK201470370A1 (en) | 2016-01-11 |
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| DK201470370A DK201470370A1 (en) | 2014-06-20 | 2014-06-20 | Apparatus for testing directionality in hearing instruments |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5703797A (en) * | 1991-03-22 | 1997-12-30 | Frye Electronics, Inc. | Method and apparatus for testing acoustical devices, including hearing aids and the like |
| US20050259829A1 (en) * | 2004-05-24 | 2005-11-24 | Cochlear Limited | Stand-alone microphone test system for a hearing device |
| US7062056B2 (en) * | 2003-09-10 | 2006-06-13 | Etymonic Design Incorporated | Directional hearing aid tester |
| US20070175281A1 (en) * | 2006-01-13 | 2007-08-02 | Siemens Audiologische Technik Gmbh | Method and apparatus for checking a measuring situation in the case of a hearing apparatus |
| US20070286429A1 (en) * | 2006-06-08 | 2007-12-13 | Siemens Audiologische Technik Gbmh | Compact test apparatus for hearing device |
-
2014
- 2014-06-20 DK DK201470370A patent/DK201470370A1/en not_active Application Discontinuation
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5703797A (en) * | 1991-03-22 | 1997-12-30 | Frye Electronics, Inc. | Method and apparatus for testing acoustical devices, including hearing aids and the like |
| US7062056B2 (en) * | 2003-09-10 | 2006-06-13 | Etymonic Design Incorporated | Directional hearing aid tester |
| US20050259829A1 (en) * | 2004-05-24 | 2005-11-24 | Cochlear Limited | Stand-alone microphone test system for a hearing device |
| US20070175281A1 (en) * | 2006-01-13 | 2007-08-02 | Siemens Audiologische Technik Gmbh | Method and apparatus for checking a measuring situation in the case of a hearing apparatus |
| US20070286429A1 (en) * | 2006-06-08 | 2007-12-13 | Siemens Audiologische Technik Gbmh | Compact test apparatus for hearing device |
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