JP4441614B2 - External sound perception device - Google Patents

Description

  The present invention relates to an external sound perception apparatus for perceiving external sound by ultrasonic vibration.

  Hearing aids for the hearing impaired are known as external sound perception devices for perceiving external sounds. Hearing aids include air-conducting hearing aids that transmit sound vibrations through the eardrum to the auditory organ of the brain, and bone-conducting hearing aids that transmit sound vibrations directly from the skull to the human body without passing through the eardrum. Yes, the vibrator is used by attaching it to a predetermined part of the human body.

Recently, a configuration in which external sound can be perceived by transmitting ultrasonic vibrations to the auditory organ of the brain via a vibrator is known. For example, Patent Literature 1 discloses an external sound perception device configured to transmit ultrasonic signals from a plurality of transducers based on external sound input to a microphone.
JP 2004-343302 A

The sound image of bone-conducted ultrasound may change greatly due to subtle differences in the attachment position of the transducer. Therefore, the device disclosed in Patent Document 1 is configured to be able to generate different vibration signals for each vibrator, and thus, the sound sensing state (independent of the attachment position of the vibrator to the living body) The optimization of the perceived state of the external sound is attempted.
However, the conventional external sound perception apparatus has no room for improvement in this respect because it cannot obtain the direction of the sound source even if a good sound sensing state is obtained.

  Therefore, an object of the present invention is to provide an external sound perception apparatus that can improve the sense of direction of perceived sound.

  The object of the present invention is based on a directional microphone to which an external sound is input, a vibration signal generating means for generating a vibration signal by modulating a carrier signal based on the input sound signal, and the vibration signal. A vibrator that transmits ultrasonic vibrations to a living body, and the directional microphone and the vibrator are provided in a plurality in association with each other, based on external sound input to each directional microphone, Ultrasonic vibration is transmitted from each corresponding transducer, and the vibration signal generation means is configured to be able to perform inherent modulation for each external sound input from each directional microphone. Accomplished by a sound perception device.

  In this external sound perception apparatus, it is preferable that the vibration signal generation unit is configured to perform amplitude modulation by changing the frequency of the carrier signal for each directional microphone.

  Further, the vibration signal generation means can be configured to perform modulation by a different modulation method for each directional microphone.

  In these external sound perception apparatuses, it is preferable that the vibration signal generating means includes an input unit capable of inputting a modulation condition for performing modulation specific to each external sound.

  ADVANTAGE OF THE INVENTION According to this invention, the external sound perception apparatus which can improve the sense of direction of a perceptual sound can be provided.

  Hereinafter, actual forms of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front view showing a schematic configuration of an external sound perception apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram thereof. As shown in FIGS. 1 and 2, the external sound perception apparatus includes a plurality of directional microphones 10 and 10 to which external sound is input, and a vibration signal generation unit that generates a vibration signal based on the input sound signal. 20 and a plurality of vibration transmission units 30 and 30 for transmitting mechanical vibration based on the vibration signal.

  The plurality of directional microphones 10 and 10 are respectively attached to a casing 20a in which the vibration signal generation unit 20 is accommodated. The directional microphones 10 and 10 are fixed so that the main axis directions of the directivities are different in the present embodiment, but the main axis directions may be attached so as to be adjustable. The external sound input to each of the directional microphones 10 and 10 is input to the vibration signal generation unit 20 after being amplified.

  The vibration signal generation unit 20 includes carrier signal generation units 22 and 22 that generate carrier signals, input units 24 and 24 that can input the frequency, amplitude, timing (phase), and modulation method of the carrier signal, and the directional microphone 10. , 10 and carrier signal modulation units 26, 26 that generate vibration signals by modulating the carrier signal based on the sound signal input from the sound signal 10, and individually input sound of each directional microphone 10,10 Generate a vibration signal.

  The input unit 24 includes a volume switch 24a that can be individually adjusted so that the frequency, amplitude, and phase of the carrier signal can be continuously changed, and further, a dial switch 24b for selecting a modulation method. It has. Examples of selectable modulation methods include frequency modulation, amplitude modulation, phase modulation, and the like, and examples of amplitude modulation include double sideband (DSB), single sideband (suppressed carrier wave) (SSB), and the like. Can be selected.

  The frequency of the carrier signal is preferably from 20 to 100 kHz, more preferably from 20 to 50 kHz, so as to obtain a good sound sensing state even for a highly deaf person. Therefore, it is preferable that the input unit 24 can adjust the frequency of the carrier signal in a range including a part or all of the frequency range.

  The vibration transmitting units 30 and 30 include vibrators that transmit vibration signals to the outside as mechanical vibrations, and each vibrator is associated with a plurality of directional microphones 10 and 10, respectively. The external sound input to the directional microphone 10 is transmitted from the corresponding vibrator.

  As shown in FIG. 3, each vibration transmission unit 30 includes a cylindrical case 32 in which a vibrator 31 is accommodated, and a suction cup 34 is attached to the opening edge of the case 32.

The vibrator 31 is supported by a gimbal mechanism so as to be swingable about two axes orthogonal to each other. That is, the vibrator 31 is fixed to the first frame body 40 so that the vibration surface is exposed, and the first frame body 40 is connected to the second frame body 44 via the first support shaft 42. It is swingably supported. The second frame body 44 is swingably supported inside the case 32 via a second support shaft 46 orthogonal to the first support shaft 42. The vibration surface of the vibrator 31 protrudes slightly from the opening of the case 32. When the suction cup 34 is attracted to a predetermined attachment site, the vibration surface of the vibrator 31 contacts and is pressed against the attracted surface. Has been. The bottom of each case 32 (
A communication hole 32a is formed at the center in the upper part of the figure, and a spherical bag 48 is coupled to the communication hole 32a. The bag-like body 48 is made of an elastic material such as a rubber material, and is configured to be elastically deformable by pressing. The internal space of the bag 48 communicates with the inside of the case 32 through the communication hole 32a.

  Next, the operation of the external sound perception apparatus will be described. First, the plurality of vibration transmission units 30 and 30 are respectively attached to predetermined parts of the human body (for example, in the vicinity of the left and right milky protrusions). Each vibrator 31 can be reliably brought into contact with the human body by the gimbal mechanism by pressing the suction cup 34 against a predetermined portion while the bag-like body 48 is picked by hand. Thereafter, when the hand that has been picked is released, the inside of the case 32 becomes a negative pressure due to the shape restoring force of the bag-like body 48 and an adsorption force is obtained, so the attachment of the vibrator 31 can be ensured.

  Thereafter, when an external sound is input to the directional microphones 10 and 10 by turning on the switch of the external sound perception device, a sound signal is input from the directional microphones 10 and 10 to the vibration signal generation unit 20. Since the directional microphones 10 and 10 have different directivity main axis directions, input sensitivities to the same sound source are different.

  In the vibration signal generation unit 20, the carrier signal generation units 22 and 22 generate a carrier signal having a predetermined amplitude and frequency, and the carrier signal modulation units 26 and 26 modulate the carrier signal based on the sound signal. Thus, a vibration signal corresponding to the input sound to each directional microphone 10, 10 is generated. At this time, different modulation conditions are input via the input unit 24 so that the carrier signal modulation units 26 and 26 perform unique modulation for each input sound to the directional microphones 10 and 10, respectively. . For example, the carrier signal frequency is set to be different for each of the directional microphones 10, 10, and the modulation method is the same double sideband amplitude modulation, and each modulation can be performed. Alternatively, the carrier signals may have the same frequency, and the modulation methods may be different from each other (for example, one is a double sideband amplitude modulation and the other is a suppressed carrier wave amplitude modulation), and each may be subjected to a specific modulation. The vibration signal generated in this way is output to each of the corresponding vibration transmission units 30 and 30.

  The vibration transmitting units 30 and 30 vibrate the vibrators 31 and 31 based on the input vibration signal. As a result, ultrasonic vibrations are transmitted from the corresponding vibration transmitting units 30 and 30 to the human body based on the external sound input to the directional microphones 10 and 10, respectively. The carrier signal modulation unit 26 performs control so as not to output a vibration signal during a period in which no sound signal is input.

  According to the external sound perception apparatus of the present embodiment, the vibration signal generation unit 20 is configured to perform specific modulation for each external sound input from each directional microphone 10, 10. Each modulation condition is set in advance so that a difference in “audibility (tone color)” of ultrasonic vibrations transmitted from the vibration transmission units 30 and 30 can be recognized, and the directional microphones 10 and 10 corresponding to the respective “hearing”. , The user can determine from which directional microphone 10 the perceived ultrasonic signal is input. For example, if the modulation method is double-sideband amplitude modulation, both the carrier wave pitch and the demodulated signal wave pitch are perceived simultaneously, while if the modulation method is suppressed carrier amplitude modulation, the carrier wave Is not perceived, and only a pitch corresponding to twice the frequency of the original signal wave is perceived, so that the difference in “hearing” can be reliably determined. As a result, it becomes possible for the user to surely recognize the direction of the sound source such as voice or environmental sound, which is effective, for example, when working at a disaster site or construction site, or when driving a vehicle such as an automobile.

In the present embodiment, the above-described configuration of the vibration transmitting unit 30 can effectively prevent positional deviation of the vibrator 31 over time, but the sound pressure distribution in the head is determined by the attachment position of each vibrator 31. Therefore, it is difficult to accurately attach each vibrator 31 to a portion where the sound sensing state is optimal. Therefore, after attaching each transducer 31, the frequency, phase, amplitude, etc. of the carrier signal corresponding to each transducer 31 are adjusted by operating the input unit 24, and the positions of the abdomen and nodes caused by ultrasonic interference are controlled. It is preferable to optimize the sound sensing state by reducing the focal point of the ultrasonic wave and locally increasing the sound pressure. When the carrier signal frequency is set to be different for each of the directional microphones 10 and 10 as the modulation condition, the carrier signal is adjusted in the sound sensing state so as not to lose the sense of direction of the perceived sound. The frequency is preferably not changed.

  Although the specific method for optimizing a sound-sensitive state is not specifically limited, For example, the following method can be mentioned. First, the amplitude of the ultrasonic waves emitted from the plurality of vibrators 31 is set to be small, and each of the vibrators 31 is appropriately attached to each mastoid so that the sound-sensing state is generally good. Perform positioning. Then, the frequency and phase of each transducer 31 are adjusted and determined so that the sound sensing state becomes better. For example, when two vibrators 31 are attached and used, the frequency of the carrier signal corresponding to each vibrator 31 is simultaneously changed to set the frequency at which the sound sensing state is the best. Thereafter, by setting the phase of the carrier signal corresponding to each vibrator 31 in the same manner, the optimum frequency and phase of the carrier signal can be obtained individually for each vibrator 31, and the sound sensing state Can be optimized. Either the frequency or phase may be set first. Finally, the amplitude is set to a desired magnitude so that a desired sound sensing state can be obtained.

  As another method for optimizing the sound sensing state, the carrier signal corresponding to the other transducer 31 while maintaining the frequency, phase and amplitude of the carrier signal corresponding to one transducer 31 at predetermined values. It is also possible to optimize the sound sensing state by sequentially changing the frequency, phase and amplitude. In this case, it is only necessary that the input unit 24 can adjust the frequency, phase, and amplitude of the carrier signal corresponding to at least one transducer 31.

  In any case, by adjusting the frequency, phase, and amplitude of the carrier signal in a state where the difference in “hearing” can be reliably determined, it is possible to obtain both a good sound feeling state and a sense of direction.

  As mentioned above, although one Embodiment of this invention was explained in full detail, the specific aspect of this invention is not limited to the said embodiment. For example, in the present embodiment, two directional microphones 10 and 10 are used, and each input sound is configured to perform unique modulation. However, the directional microphone and vibration transmission corresponding to the directional microphone are used. The number of parts is not particularly limited as long as it is plural. For example, when this external sound perception device is installed in an automobile, four directional microphones are fixed to the vehicle so that the main axes of directivity are forward, backward, right, and left, respectively. The sound may be configured to be transmitted to the human body through four corresponding vibration transmission units after performing a specific modulation on the sound. This makes it possible to reliably grasp the direction of a sound source that needs to be recognized during driving, such as a siren of an emergency vehicle.

  In this embodiment, the modulation condition can be input via the input unit 24. However, by determining a modulation condition suitable for the user in advance and storing the data in a memory or the like. A configuration without the input unit 24 is also possible. Moreover, the input of the change condition from the input unit 24 is not limited to manual operation, and the result of measurement and calculation by another device may be automatically input.

First, in order to examine whether or not the subject can discriminate the presentation site of the ultrasonic bone conduction sound, the brain magnetic field (MEG) when bone conduction ultrasonic stimulation is presented to the left and right mastoid processes according to the oddball task is shown. Measured. The application of bone-conducted ultrasonic stimulation is performed by 30 kHz ultrasonic waves that are amplitude-modulated (modulation rate 100%) with a tone burst with a frequency of 1 kHz (duration 30 ms, rise and fall times 10 ms each). The cerebral magnetic field when a low frequency stimulus (presentation probability 10%) and a high frequency stimulus (presentation probability 90%) are applied to the other side, the right side is a low frequency stimulus (left side is a high frequency stimulus), and the left side Was compared with the case of low frequency stimulation (high frequency stimulation on the right side).

  FIG. 4A shows the waveform of the cerebral magnetic field measured at the right temporal region of the subject for each of the low-frequency stimulation and the high-frequency stimulation. In any case, the N1m response was observed about 100 ms after the presentation of the stimulus, but the amplitude of the N1m response was larger with the low frequency stimulus, and a mismatch response was observed. For comparison, when the same measurement was performed with a bone-conducted audible sound having a frequency of 2 kHz, a mismatch reaction was observed in the same latency as shown in FIG. 4B.

  As described above, the two bone-conducted ultrasonic stimuli can be discriminated similarly to the case of bone-conducted audible sound, and it is objective that the subject can discriminate the presenting part (presentation side) of the ultrasonic bone-conducted sound. Could be revealed.

  Next, in order to check whether or not the input sound itself presented on the mastoid can be discriminated, as a modulation condition in the above embodiment of the present invention, the frequency of the carrier signal is made different for each directional microphone 10, 10. The relationship between the frequency of the sinusoidal bone conduction sound and the pitch (subjective sound pitch) when the modulation method is the same double-sideband amplitude modulation is set to 4 subjects (normal hearing people). Was measured.

  The pitch is measured in a sound-free room, and a piezoelectric ceramic vibrator is fixed to the subject's milky process by a headband to present bone-conducted sound, while the other ear receives air conduction through headphones. When presenting sound and presenting bone-conducted sound of each frequency of 16k, 20k, 24k, 28k, 32k, 36k, and 40k (Hz), the frequency of the air-conducted sound with the same pitch is adjusted (subject himself / herself). It was obtained by a method of changing the frequency of the air conduction sound by adjusting the dial). The measurement was performed twice by switching the presentation side of the bone conduction sound and the air conduction sound, and the average value of these two times was calculated for each subject. The result is shown in FIG.

  As shown in FIG. 5, in the ultrasonic frequency band, there is no monotonically increasing relationship between the bone conduction sound frequency and the pitch as in the case of an audible sound, and the variation pattern varies depending on the subject. However, in any subject, it can be seen that the pitch fluctuates up and down 1-2 kHz as the bone conduction sound frequency increases. If there is such a pitch fluctuation, the subject can easily discriminate the difference. Therefore, in an actual product, the bone conduction sound frequency that can easily distinguish the pitch difference is selected in advance, and the selected bone is selected. By making the sound guide frequency the frequency of the carrier signal, it is possible to clearly distinguish inputs from a plurality of vibrators.

It is a front view which shows schematic structure of the external sound perception apparatus which concerns on one Embodiment of this invention. It is a block diagram of the external sound perception device. It is sectional drawing of the vibration transmission part in the said external sound perception apparatus. It is a figure which shows the experimental result for verifying the effect of the external sound perception apparatus shown in FIG. It is a figure which shows the other experimental result for verifying the effect of the external sound perception apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Directional microphone 20 Vibration signal generation part 22 Carrier signal generation part 24 Input part 26 Carrier signal modulation part 30 Vibration transmission part 31 Vibrator

Claims (4)

An external sound perception device for perceiving external sound by ultrasonic vibration,
A directional microphone to which external sound is input;
Vibration signal generating means for generating a vibration signal by modulating a carrier signal based on the input sound signal;
A vibrator that transmits ultrasonic vibrations to a living body based on the vibration signal;
A plurality of the directional microphones and the vibrators are provided in association with each other, and ultrasonic vibrations are transmitted from the corresponding vibrators based on external sound input to the directional microphones. ,
The external sound perception apparatus is configured such that the vibration signal generation means can perform modulation specific to each external sound input from each of the directional microphones. The external sound perception apparatus according to claim 1, wherein the vibration signal generation unit can perform amplitude modulation by changing a frequency of a carrier signal for each directional microphone. The external sound perception apparatus according to claim 1, wherein the vibration signal generation unit can perform modulation by a different modulation method for each directional microphone. The external sound perception apparatus according to claim 1, wherein the vibration signal generation unit includes an input unit capable of inputting a modulation condition for performing modulation specific to each external sound.

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