Audio device and audio control method

Abstract

To efficiently reduce noise such as a vibration sound occurring in accordance with a motion during user's exercise such as jogging, and prevent degradation of the sound quality of a sound acoustically output.SOLUTION: An acoustic device includes: a sound emitting unit that is attached to a user who is exercising, and acoustically outputs a sound signal; at least one sensor that periodically detects acceleration in three directions including a forward-backward direction, a left-right direction, and an up-down direction of the user; a vibration sound peak detection unit that detects peaks of vibration sounds, based on movements of the user when the detected values of acceleration in each of the forward-backward direction, the left-right direction, and the up-down direction satisfy prescribed conditions; and a signal processing unit that determines whether or not time intervals at which the peaks of the vibration sounds are detected are periodic. If it is determined that the time intervals at which the peaks of the vibration sounds are detected are periodic, the signal processing unit sets, on the basis of the peaks of the vibration sounds, the gain of a cancel signal suppressed from a sound signal acoustically output from the sound emitting unit.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to an audio device and an audio control method. [Background technology]

[0002] There is a known technology for canceling noise by superimposing a sound of an opposite phase to the noise leaking into the ear pad of a headphone on a sound based on an input audio signal and outputting the sound from within the ear pad. For example, Patent Document 1 proposes a headphone with a noise reduction device that reduces the amount of noise cancellation when a specific sound is generated externally. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-59376 A Summary of the Invention [Problem to be solved by the invention]

[0004] According to Patent Document 1, when a specific sound (e.g., an emergency vehicle siren or a train crossing sound) occurs, the amount of noise cancellation is reduced, so that the user can hear the specific sound (see above) emitted from the outside without lowering the volume while listening to music based on an audio signal supplied from an audio device. However, Patent Document 1 does not take into consideration the efficient reduction of noise such as vibration noise with a high level that is generated when the user is moving their body, such as jogging (e.g., feet touching the ground while jogging).

[0005] The present disclosure provides an audio device and an audio control method that efficiently reduces noise such as vibration noise generated in response to a user's movements during exercise such as jogging, and suppresses deterioration of the quality of sound that is acoustically output. [Means for solving the problem]

[0006] The present disclosure relates to an acoustic device worn by a user during exercise, the acoustic device comprising: a sound emitting unit that acoustically outputs a sound signal; at least one sensor that periodically detects acceleration in three directions consisting of a forward / backward direction, a left / right direction, and an up / down direction of the user; a vibration sound peak detection unit that detects a peak of a vibration sound based on the movement of the user when the detected values ​​of acceleration in each of the forward / backward direction, the left / right direction, and the up / down direction satisfy a predetermined condition; and a signal processing unit that determines whether or not a time difference at which the peak of the vibration sound is detected is periodic, and the signal processing unit detects a time difference at which the peak of the vibration sound is detected as a periodic time difference. Level The present invention provides an acoustic device that sets a gain of a cancellation signal to be suppressed from the sound signal acoustically output from the sound emitting section based on the above.

[0007] The present disclosure also provides an acoustic control method executed by an acoustic device worn by a user during exercise, the method comprising the steps of: acoustically outputting a sound signal; periodically detecting acceleration in three directions, namely, a forward / backward direction, a left / right direction, and an up / down direction of the user, at at least one location; detecting a peak of a vibration sound based on the movement of the user when the detected values ​​of acceleration in each of the forward / backward direction, the left / right direction, and the up / down direction satisfy a predetermined condition; and judging whether or not a time difference at which the peak of the vibration sound is detected is periodic, and when it is judged at the time of the judgment that the time difference at which the peak of the vibration sound is detected is periodic, detecting a peak of the vibration sound based on the movement of the user. Level The present invention provides an acoustic control method for setting a gain of a cancellation signal to be suppressed from the sound signal that is acoustically output based on the above. Effect of the Invention

[0008] According to the present disclosure, it is possible to efficiently reduce noise such as vibration sounds generated in response to the movements of a user during exercise such as jogging, and to suppress deterioration in the quality of sound that is acoustically output. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a side view illustrating a state in which the headphones according to the first embodiment are worn on a user's head. [Diagram 2] FIG. 2 is a cross-sectional view showing a schematic example of the internal hardware configuration of the headphones shown in FIG. [Diagram 3] A schematic diagram explaining the setting of the coordinate system for the headphones shown in Figure 2. [Figure 4] A functional block diagram illustrating the processing on the circuit board shown in FIG. [Diagram 5] A flowchart illustrating a process flow in the circuit board shown in FIG. [Figure 6] Graph showing the change over time in the Z-component acceleration signal detected by the acceleration sensor shown in FIG. 2. [Figure 7] Graph showing frequency and level characteristics of Z component acceleration signal [Figure 8] FIG. 11 is a functional block diagram illustrating processing on a circuit board according to a second embodiment; [Figure 9] A flowchart illustrating a process flow in the circuit board shown in FIG. 8. [Figure 10] FIG. 11 is a functional block diagram illustrating processing on a circuit board according to a third embodiment; [Figure 11] A flowchart illustrating a process flow in the circuit board shown in FIG. [Figure 12] FIG. 13 is a functional block diagram illustrating processing on a circuit board according to a fourth embodiment; [Figure 13] A flowchart illustrating a process flow in the circuit board shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, with reference to the drawings as appropriate, a detailed description will be given of several embodiments that specifically disclose the acoustic device and the acoustic control method according to the present disclosure. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or duplicate description of substantially the same configuration may be omitted. This is to avoid the following description becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Also, each of the attached drawings will be referred to according to the direction of the symbols. Note that the attached drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0011] For example, in this disclosure, an overhead headphone worn on the user's head as an acoustic device is described as an example of the disclosure, but the disclosure is not limited to this and may be an earphone type. That is, the disclosure can be applied to earphones that do not have a main body as a casing that surrounds or covers the ears and ear pads. In addition, the contents of the disclosure can be appropriately applied to any device that has a driver, a microphone, etc., and is not limited to the form of headphones or earphones, but is used as an acoustic device.

[0012] In addition, the term "unit" or "device" in each embodiment is not limited to a physical configuration that is mechanically realized by hardware, but also includes a configuration whose functions are realized by software such as a program. Also, the functions of one configuration may be realized by two or more physical configurations, or the functions of two or more configurations may be realized by, for example, one physical configuration.

[0013] (Embodiment 1) A first embodiment of the present disclosure will be described with reference to FIGS. 1 to 7. FIG.

[0014] [Headphone hardware configuration] The hardware configuration of headphones 1 (an example of an audio device) according to this embodiment will be described with reference to Figs. 1 to 3. Fig. 1 is a side view illustrating a state in which headphones 1 according to this embodiment are worn on the head of a user U. Fig. 2 is a cross-sectional view that typically illustrates an example of an internal hardware configuration of headphones 1 shown in Fig. 1. Fig. 3 is a schematic diagram that typically illustrates the setting of a coordinate system in headphones 1 shown in Fig. 2.

[0015] As shown in FIG. 1 and FIG. 2, the headphones 1 of the present embodiment are, for example, an over-the-ear type, and are configured to have a headband 2 and a pair of main body parts 3 disposed at both ends of the headband 2. In the present embodiment, the headphones 1 have a wireless communication unit CP1 (see FIG. 4) capable of communication according to, for example, the Bluetooth (registered trademark) communication standard, and are wirelessly connected to a sound source device such as a radio device or a music playback device for music playback, or to a telephone device such as a smartphone P (an example of a terminal) for telephone use. The headphones 1 receive audio signals, music signals, control signals, and the like transmitted from these devices in the wireless communication unit CP1 (see FIG. 4), and output the audio signals as sound waves, or collect the speech of a user U and transmit the collected audio results to these devices. In the present embodiment, the headphones 1 will be described with a smartphone P as an example of a device with which the headphones 1 will wirelessly communicate, but the present embodiment is not limited to this, and the headphones 1 can be connected to various devices as long as they are capable of wireless communication. In the following description, the term "audio signal" also includes the concept of a music signal unless otherwise specified.

[0016] The headband 2 is made of a long member, curved in a substantially arcuate shape, and elastically provided. The headband 2 sandwiches the head of the user U from both the left and right sides when the headphones 1 are worn by the user U. This allows the headband 2 to press the pair of main bodies 3 against the left and right sides of the head of the user U due to its elasticity, thereby making it possible to fix the headphones 1 to the head of the user U. Note that the headband 2 of this embodiment may be provided with a pair of expansion and contraction mechanisms, and the length of the headband 2 may be adjusted according to the size of the user U's head by expanding and contracting each of the pair of expansion and contraction mechanisms.

[0017] Each of the pair of main bodies 3 is a member that comes into contact with the ear of a user U wearing the headphones 1, and is formed in a dome shape or an egg shape. When the headphones 1 are worn on the head of the user U, each of the pair of main bodies 3 is positioned so as to cover the ear of the user U, and this positioned state is the normal use state of the headphones 1. Each of the pair of main bodies 3 is configured to include a housing 4, a partition plate 6, and ear pads 7 as structural members.

[0018] The housing 4 is formed in a dome shape forming the outer contour of the main body 3, and has an opening 5. The housing 4 is attached to the headband 2 such that the openings 5 ​​are positioned opposite each other across the head of the user U when the headphones 1 are worn by the user U.

[0019] The partition plate 6 is a plate-like member that is disposed within the main body 3 and closes the opening 5 of the housing 4. A through hole is formed in the center of the partition plate 6, and a driver 10 (described later) is inserted and fixed into the through hole. The housing 4 and the partition plate 6 define a storage space S2.

[0020] The ear pads 7 are formed in an annular shape and cover the ears of the user U wearing the headphones 1 from the sides. The ear pads 7 are arranged extending in the circumferential direction at the periphery of the opening 5 of the housing 4. The ear pads 7 are made of a soft resin material and are provided so as to be deformable in accordance with the shape of the ears of the user U. This deformation makes it possible to improve the adhesion between the ear pads 7 and the periphery of the ears of the user U. An acoustic space S1 is partitioned by the ear pads 7 and the partition plate 6. When the headphones 1 are worn by the user U, the acoustic space S1 becomes a sealed space including the auricle of the user U in the contact area of ​​the ear pads 7. In the acoustic space S1, the ear pads 7 physically suppress the leakage of sound to the outside of the headphones 1 and the intrusion of ambient sound into the inside of the headphones 1.

[0021] In addition, each of the pair of main body parts 3 is configured to include, as electrical and electronic components, a driver 10 (an example of a sound emitting part), a plurality of microphones (e.g., an internal microphone 8A, an external microphone 8B, and a speaking microphone 8C), a bone conduction sensor 9 (an example of a speaking sensor), a circuit board 20, and an acceleration sensor 11 (an example of a sensor).

[0022] The driver 10 outputs a signal such as an audio signal or a music signal. Specifically, the driver 10 has a built-in diaphragm, and converts the audio signal into a sound wave (i.e., air vibration) by vibrating the diaphragm based on the audio signal input to the driver 10. The sound wave output from the driver 10 propagates to the eardrum of the user U's ear.

[0023] The multiple microphones include at least three types of microphones: an internal microphone 8A, an external microphone 8B, and a microphone for speech 8C. In this embodiment, the external microphone 8B and the microphone for speech operate as a sound collection device that collects sounds around the user U, as described later.

[0024] The internal microphone 8A is disposed with its detection portion facing the acoustic space S1, which is partitioned by the ear pad 7 and the partition plate 6. The internal microphone 8A is disposed as close as possible to the ear canal of the ear of the user U, inside the acoustic space S11. As a result, the internal microphone 8A picks up sounds that are physically generated inside the acoustic space S1, including sound waves output from the driver 10.

[0025] That is, the internal microphone 8A is provided so as to be able to pick up noise entering the acoustic space S1 through the housing 4, the ear pads 7, etc. as a wraparound sound signal together with the audio signal or music signal output from the driver 10. The internal microphone 8A is also electrically connected to the circuit board 20 by a signal line, and the detection result is transmitted to the circuit board 20.

[0026] The external microphone 8B and the speech microphone 8C are stored in a storage space S2 partitioned by the housing 4 and the partition plate 6. A plurality of through holes are formed in the housing 4, and the external microphone 8B and the speech microphone 8C are attached to the housing 4 so as to be able to pick up sounds outside the headphones 1 through each of these through holes.

[0027] The external microphone 8B is positioned so as to be able to pick up ambient noise outside the headphones 1. The speech microphone 8C is positioned so as to be able to pick up speech from a user U wearing the headphones 1, and together with the driver 10, the headphones 1 are capable of communicating with a mobile phone device such as a smartphone P, thereby realizing a so-called hands-free call. The external microphone 8B and speech microphone 8C are also electrically connected to the circuit board 20 by signal lines, and the detection results are transmitted to the circuit board 20.

[0028] The bone conduction sensor 9 includes a piezoelectric element and converts vibrations (bone conduction vibrations) transmitted to the human bones of the user U into an electric signal. The bone conduction sensor 9 is attached to the headphones 1 so as to be in contact with the surface of the face around the ear or the back surface of the auricle. In the acoustic space S1, the bone conduction sensor 9 is disposed at a distance from the driver 10. Since the voice uttered by the user U is conducted to the bones of the face or head, the bone conduction sensor 9 detects the vibrations of the human bones, converts the detection result into an electric signal, and outputs it. The speech of the user U can be detected by this electric signal. The bone conduction sensor 9 is electrically connected to the circuit board 20 by a signal line, and the detection result is transmitted to the circuit board 20.

[0029] In this embodiment, the acceleration sensor 11 is embedded in one of the pair of main bodies 3 (the left main body 3 in this embodiment). The acceleration sensor 11 converts the bone conduction vibration of the user U into an electric signal, similar to the bone conduction sensor 9, and detects the vibration as a vibration signal when the user U is moving his / her body through sports (e.g., jogging, yoga, marathon, exercise, etc.). For example, when the user U is running, such as jogging, the acceleration sensor 11 is configured to be able to detect the impacts of kicking the ground alternately with both feet as impulse signals of acceleration corresponding to each of the impacts (see FIG. 6, described later).

[0030] 3, the acceleration sensor 11 is configured to be capable of periodically detecting vibrations (accelerations) in three axial directions of the user U, namely, the up-down direction (vertical direction according to gravity, hereinafter also referred to as the "Z-axis direction"), the front-rear direction (hereinafter also referred to as the "Y-axis direction"), and the left-right direction (hereinafter also referred to as the "X-axis direction"), in each of the components when the user U is wearing the headphones 1. That is, in this embodiment, the detection coordinate system Σ-XYZ of the acceleration sensor 11 is set so that, for example, when the user U is running, the Z-axis direction is the vertical direction, the Y-axis direction is the running direction of the user U, and the X-axis direction is the rocking direction (lateral swaying direction) of the user U. The acceleration sensor 11 transmits the detection results to the circuit board 20 as vibration signals in each of the XYZ components.

[0031] The circuit board 20 is formed in a flat plate shape, and a plurality of circuits are arranged on its surface. The circuit board 20 has a plurality of arithmetic circuits (see, for example, the processors PRC1 and PRC2 shown in FIG. 4), read-only memory circuits (see, for example, the ROMs 35 and 47 shown in FIG. 4), and writeable memory circuits (see, for example, the RAMs 34 and 46 shown in FIG. 4), and operates as a minicomputer for the headphones 1 that appropriately processes audio signals.

[0032] [Circuit board configuration] Next, the configuration of the circuit board 20 will be described with reference to Fig. 4. Fig. 4 is a functional block diagram illustrating the processing on the circuit board 20 shown in Fig. 2. As described above, the circuit board 20 is configured as a general-purpose minicomputer, and a program as software stored and held in each circuit section (for example, the ROM 35 of the first circuit section 30 shown in Fig. 4, and the ROM 47 of the second circuit section 40 shown in Fig. 4) is read and executed by a calculation device (see above, for example, the processors PRC1 and PRC2 shown in Fig. 4).

[0033] In this embodiment, a plurality of integrated circuits that specialize in performing predetermined processing as hardware that is physically mounted on the circuit board 20 are also mounted on the circuit board 20. In other words, each block illustrated inside the circuit board 20 shown in Fig. 3 represents a function realized by software such as a program, or a function realized by hardware such as a dedicated integrated circuit.

[0034] In addition, in the present embodiment, the functions realized by the circuit board 20 are realized by both software and hardware, but this is not limiting. For example, all of the functions may be realized by hardware as the physical configuration of the "device."

[0035] Furthermore, as described above, the circuit board 20 is equipped with a wireless communication unit CP1, and in this embodiment, the circuit board 20 is wirelessly connected to a smartphone P carried by a user U via the wireless communication unit CP1. Also, in this embodiment, the wireless communication unit CP1 of the headphones 1 performs communication according to, for example, a Bluetooth (registered trademark) communication standard, but is not limited thereto, and may be provided so as to be connectable to a communication line such as Wi-Fi (registered trademark) or a mobile communication line.

[0036] The smartphone P of the user U has a display unit, and an application is installed on the smartphone P. This application turns on or off the shock cancellation function of the headphones 1 when the user U operates the display unit (see FIG. 5, described below).

[0037] 4, at least a first circuit section 30 and a second circuit section 40 are provided on the circuit board 20. The first circuit section 30 and the second circuit section 40 are configured to control each other in a coordinated manner by transmitting and receiving control signals to each other, and to be able to exchange audio signals as PCM digital signals or the like.

[0038] The first circuit unit 30 has a processor PRC1, a RAM (Random Access Memory) 34, a ROM (Read Only Memory) 35, and a wireless communication unit CP1. The processor PRC1 is configured using, for example, a CPU (Central Processing Unit), a DSP (Digital Signal Processor), or an FPGA (Field Programmable Gate Array). Specifically, the processor PRC1 is configured to include an LPF unit 31, a vibration sound processing unit 32 (an example of a vibration sound peak detection unit), and a BPF / gain setting unit 33 (an example of a signal processing unit).

[0039] The LPF unit 31 receives a vibration signal (vibration sound) transmitted from an analog-digital conversion unit 41 (described later) of the second circuit unit 40. The LPF unit 31 has a function of a low pass filter, and removes high-frequency components from the components of the received vibration signal, passing only low-frequency components (see FIG. 7). In other words, the LPF unit 31 removes noise contained in the vibration signal detected by the acceleration sensor 11, and transmits the vibration signal in a noise-removed state to the vibration sound processing unit 32 and the ANC unit 42 (described later) of the second circuit unit 40.

[0040] The vibration sound processing unit 32 receives the vibration signal transmitted from the LPF unit 31, and is wirelessly connected to the smartphone P of the user U through the wireless communication unit CP1 of the circuit board 20 to transmit and receive audio signals and control signals transmitted from the smartphone P. In other words, the vibration sound processing unit 32 is provided so that it can input audio signals or music signals for playback from the smartphone P. Based on the audio signals and control signals transmitted from the smartphone P of the user U, the vibration sound processing unit 32 determines whether the operation mode (use) of the headphones 1 is for music playback or for phone calls, and manages the input.

[0041] In this embodiment, the vibration sound processing unit 32 detects a peak of the vibration signal (vibration sound) based on the movement of the user U when the detected acceleration value satisfies a predetermined condition in each of the Y-axis direction (front-back direction, running direction of the user U), the X-axis direction (left-right direction, swinging direction of the user U), and the Z-axis direction (up-down direction, vertical direction) (see FIG. 3) based on the received vibration signal. The vibration sound processing unit 32 transmits the voice signal or music signal from the smartphone P of the user U to the BPF / gain setting unit 33 together with the peak detection result.

[0042] The BPF / gain setting unit 33 receives the audio signal from the vibration sound processing unit 32. The BPF / gain setting unit 33 has a band pass filter function and passes audio components of a predetermined frequency band from the received audio signal (see FIG. 7). At the same time, the BPF / gain setting unit 33 adjusts the gain (in other words, the level) of the passed audio signal. Furthermore, as described later, the BPF / gain setting unit 33 determines whether the time difference at which the peaks of the vibration sound are detected is periodic or not.

[0043] Furthermore, when the BPF / gain setting unit 33 determines that the time difference at which the peaks of the vibration sound are detected is periodic, it sets the gain of a cancellation signal to be suppressed from the audio signal (sound signal) acoustically output from the driver 10, based on the peaks of the vibration sound. The BPF / gain setting unit 33 transmits the audio signal in which the gain of the cancellation signal has been set to the adder unit 43 of the second circuit unit 40. Furthermore, the BPF / gain setting unit 33 transmits a control signal (e.g., ON / OFF control, volume control, etc.) for controlling the input of the ANC unit 42 of the second circuit unit 40 to the adder unit 43, thereby managing the operation of the adder unit 43.

[0044] The RAM 34 is, for example, a work memory used when the processor PRC1 is operating, and temporarily stores data or information generated during the operation of the processor PRC1.

[0045] ROM 35 stores in advance, for example, programs and data necessary for executing the operation of processor PRC1. Although RAM 34 and ROM 35 are illustrated as being provided as separate components in FIG. 4, RAM 34 and ROM 35 may be provided within processor PRC1, and the same applies to each embodiment described below. RAM 34 and ROM 35 may also be realized by a single memory (for example, a flash memory) having the functions of RAM 34 and ROM 35.

[0046] The second circuit unit 40 includes a processor PRC2, a RAM 46, and a ROM 47. The processor PRC2 is configured using, for example, a CPU, a DSP, or an FPGA. Specifically, the processor PRC2 includes an analog-to-digital conversion unit 41, an ANC unit 42, an addition unit 43, a digital-to-analog conversion unit 44, and an amplifier unit 45.

[0047] The analog-to-digital conversion unit 41 is electrically connected to the acceleration sensor 11, receives an analog signal of the vibration signal detected by the acceleration sensor 11, and converts the analog signal into a digital signal. The analog-to-digital conversion unit 41 transmits the digital signal to the LPF unit 31 of the first circuit unit 30.

[0048] The ANC unit 42 has an active noise removal function, and receives a digital signal of the vibration signal from the LPF unit 31 of the first circuit unit 30, and dynamically generates, for example, an inverse phase signal of the digital signal as a cancellation signal to be suppressed from the audio signal acoustically output from the driver 10. The ANC unit 42 transmits the dynamically generated cancellation signal to the adder unit 43.

[0049] The adder unit 43 receives the antiphase signal (an example of a cancellation signal) from the ANC unit 42 and the audio signal from the BPF / gain setting unit 33, adds these signals, and transmits the addition result to the digital-to-analog conversion unit 44. During this addition process, the adder unit 43 dynamically controls the on / off of the addition process or the volume of the signal output from the ANC unit 42, based on the control signal transmitted from the BPF / gain setting unit 33 described above. This dynamic addition process actively removes or suppresses periodic noise (see FIG. 6) generated by the user U playing sports such as jogging, which will be described later.

[0050] The digital-to-analog converter 44 converts the sum of the adder 43 into an analog signal, and transmits the converted analog signal to the amplifier 45 .

[0051] The amplifier section 45 is electrically connected to the driver 10 , amplifies the analog signal transmitted from the digital-to-analog conversion section 44 , and transmits the amplified signal to the driver 10 .

[0052] The RAM 46 is, for example, a work memory used when the processor PRC2 is operating, and temporarily stores data or information generated during the operation of the processor PRC2.

[0053] ROM 47 stores in advance, for example, programs and data necessary for executing the operation of processor PRC2. Although RAM 46 and ROM 47 are illustrated in FIG. 4 as being provided as separate components, RAM 46 and ROM 47 may be provided within processor PRC2, and the same applies to each embodiment described below. RAM 46 and ROM 47 may also be realized by a single memory (for example, a flash memory) having the functions of RAM 46 and ROM 47.

[0054] Based on the transmission, the driver 10 outputs a signal such as an audio signal or a music signal as a physical air vibration (sound wave).

[0055] [Processing flow for circuit boards] Next, a process flow in the circuit board 20 according to this embodiment will be described with reference to Fig. 5 to Fig. 7. Fig. 5 is a flow chart illustrating a process flow in the circuit board 20 shown in Fig. 4. Fig. 6 is a graph showing a change over time in the Z-component acceleration signal detected by the acceleration sensor 11 shown in Fig. 2. Fig. 7 is a graph showing the frequency and level characteristics of the Z-component acceleration signal.

[0056] 5, the circuit board 20 of the headphones 1 determines whether or not the shock cancellation function of the headphones 1 is on based on an input operation of a user operation to an application of the smartphone P of the user U via wireless communication (S101). If it is determined that the shock cancellation function is not on (NO in S101), the processing flow ends.

[0057] On the other hand, if it is determined that the headphones are on (YES in S101), the acceleration sensor 11 of the headphones 1 periodically detects vibrations (acceleration) in each of the three axial directions (see FIG. 3) of the user U, consisting of the Z-axis direction, the Y-axis direction, and the X-axis direction, of the user U while the user U is wearing the headphones 1, for each of the components thereof.

[0058] Here, as shown in Fig. 6, in the Z-axis direction, the acceleration sensor 11 basically detects a vibration signal in which the amplitude level of a high-frequency component is superimposed on the amplitude level of a low-frequency component. When the user U is wearing the headphones 1 and playing sports (for example, jogging or running a marathon), the acceleration sensor 11 detects periodic impacts accompanying the alternate landing of both feet (Zpeak in Fig. 6) since jogging is a periodic exercise in which both feet land alternately. The periodic impacts are detected as peaks (impulse signals) of the vibration signal corresponding to the movement of the user U during exercise such as jogging. In this embodiment, as described later, the vibration sound processing unit 32 detects the peaks of the vibration sound in the Z-axis direction as signals corresponding to the movement of the user U.

[0059] Returning to Fig. 5, the explanation will be continued. As shown in Fig. 5, the LPF unit 31 receives the vibration signal (vibration sound) detected by the acceleration sensor 11, and with a cutoff frequency set to, for example, 100 Hz, removes high-frequency components from each of the X-axis component, Y-axis component, and Z-axis component of the vibration signal. By removing the high-frequency components, the LPF unit 31 passes only low-frequency components from each of the three-axis components (S103).

[0060] The vibration sound processor 32 integrates the vibration signals of these three axial components to calculate an integral value ΣX of the X-axis component, an integral value ΣY of the Y-axis component, and an integral value ΣZ of the Z-axis component. Based on the calculation results, the vibration sound processor 32 judges whether the integral value ΣY of the Y-axis component is greater than the integral value ΣX of the X-axis component and whether the integral value ΣY of the Y-axis component is greater than the integral value ΣZ of the Z-axis component (S104). These integral values ​​ΣX, ΣY, and ΣZ are integral values ​​of acceleration, which is vibration sound, and therefore the integral values ​​correspond to the moving speed. In other words, this judgment (S104) is equivalent to judging whether the moving speed in the Y-axis direction is greater than both the moving speeds in the X-axis direction and the Z-axis direction, and it is possible to estimate whether the user U is exercising, such as jogging, as a physical phenomenon. If it is judged that none of them are greater, the process flow returns to step S102.

[0061] On the other hand, if the determination result is that the acceleration is large, the vibration sound processing unit 32 estimates that the user U is exercising, such as jogging, and determines whether the absolute value |Z| of the acceleration (vibration signal) in the Z-axis direction is larger than the absolute value |X| of the acceleration in the X-axis direction and whether the absolute value |Z| of the acceleration in the Z-axis direction is larger than the absolute value |Y| of the acceleration in the Y-axis direction. In this determination, the presence or absence of an impact in the Z-axis direction due to exercise such as jogging is detected. That is, in exercise such as jogging, both feet land alternately while running and the ground is pushed back by the reaction, so that an impulse-like vibration signal is generated in the Z-axis direction. As a result, the absolute amount of acceleration is larger in the Z-axis direction compared to the X-axis and Y-axis directions. By determining this magnitude, the vibration sound processing unit 32 can estimate the occurrence of an impact according to the movement of the user U during exercise, such as jogging.

[0062] If it is determined that the absolute value |Z| of the acceleration in the Z-axis direction is smaller than the absolute value |X| of the acceleration in the X-axis direction, or the absolute value |Z| of the acceleration in the Z-axis direction is smaller than the absolute value |Y| of the acceleration in the Y-axis direction (NO in S105), the processing flow returns to step S102.

[0063] On the other hand, if it is determined that the absolute value |Z| of the acceleration in the Z-axis direction is greater than both of the absolute values ​​|X| and |Y|, the vibration sound processing unit 32 detects the peak Zpeak of the vibration signal (vibration sound) in the Z-axis direction based on the time characteristics of the acceleration level (see Figure 6).

[0064] In other words, in this embodiment, if it is determined that the movement speed in the Y-axis direction is greater than the movement speed in the X-axis direction and the movement speed in the Z-axis direction, and the absolute value of the acceleration in the Z-axis direction is greater than the absolute value of the acceleration in the Y-axis direction and the absolute value of the acceleration in the X-axis direction, the vibration sound processing unit 32 detects the peak Zpeak of the vibration signal (S104, S105).

[0065] After detecting the peak of the vibration sound, the vibration sound processor 32 calculates the difference between the peak (peak level) Zpeak in the Z-axis direction and the average value Zave of the acceleration in the Z-axis direction in a predetermined period. Then, the vibration sound processor 32 judges whether or not this difference is greater than a first threshold value TH1 (set to 6 dB in this embodiment, for example, an example of a first predetermined value). If it is judged that the difference is less than or equal to the first threshold value TH1 (NO in S106), the process flow returns to step S102.

[0066] On the other hand, if it is determined that the vibration sound is large (YES in S106), the vibration sound processing unit 32 differentiates the peak Zpeak of the detected vibration sound and determines whether the differentiation result (differential value ΔZpeak) is greater than a second threshold value TH2 (set to, for example, 3 dB in this embodiment, an example of a second predetermined value) (S107). If it is determined that the vibration sound is equal to or less than the second threshold value TH2 (NO in S107), the process flow returns to step S102. In this embodiment, the first threshold value TH1 and the second threshold value TH2 are, for example, set and stored in advance in the ROM 35, but may be set so as to be dynamically optimized using learning data (described later) generated by a machine learning technique such as deep learning. By making the first threshold value TH1 and the second threshold value TH2 dynamically adjustable, the accuracy of estimating the occurrence of an impact according to the movement of the user U during exercise is further improved.

[0067] On the other hand, if it is determined that the differential value ΔZpeak is greater than the second threshold value TH2 (YES in S107), the BPF / gain setting unit 33 determines that the time difference at which the peak Zpeak of the vibration sound is detected is periodic, identifies the detection time of the peak Zpeak of the vibration sound, and detects the peak period Tzpeak of the vibration sound.

[0068] In other words, if the BPF / gain setting unit 33 determines that the difference between the peak Zpeak in the Z-axis direction during a specified period and the average value Zave of the vibration sound during the specified period is greater than the first threshold value TH1 and that the differential value ΔZpeak (an example of the amount of change) of the peak Zpeak of the vibration sound during the specified period is greater than the second threshold value TH2, it identifies the detection time of the peak of the vibration sound (S106 to S108).

[0069] After identifying the detection time of the peak of the vibration sound and detecting the peak period Tzpeak, the BPF·gain setting unit 33 judges whether the peak period Tzpeak is within a predetermined period range (for example, 90 to 120 Hz in this embodiment) (S109). This predetermined period range is set corresponding to a period range corresponding to a running motion such as jogging of the user U, and this judgment makes it possible to estimate with higher accuracy whether the user U is running or not. If it is judged that the period is not within the predetermined period range (NO in S109), that is, it is finally estimated that the user U is not in a running state, and the processing flow returns to step S102.

[0070] On the other hand, if it is determined that the period is within the predetermined period range (YES in S109), that is, it is finally estimated that the user U is in a running state, and the BPF / gain setting unit 33 performs low-pass filter processing on the vibration sound to remove high-frequency components and pass only low-frequency components in terms of frequency characteristics related to acceleration as shown in Fig. 7. Furthermore, the BPF / gain setting unit 33 performs band-pass filter processing on the range including the peak period Tzpeak (S110).

[0071] Returning to Fig. 5, the explanation will be continued. As shown in Fig. 5, the BPF / gain setting unit 33 detects and sets the level of the peak Zpeak of the vibration sound based on the processing of the band pass filter (S111). Furthermore, the BPF / gain setting unit 33 sets the gain of a cancellation signal in the Z-axis direction to be suppressed from the audio signal acoustically output from the driver 10 based on the level of the set peak Zpeak (S111). The ANC unit 42 generates a cancellation signal to be suppressed from the audio signal acoustically output from the driver 10 based on the setting of the gain of the peak Zpeak of the vibration sound, and transmits the cancellation signal to the addition unit 43.

[0072] In this embodiment, the above-mentioned predetermined period range is also set in advance and stored in, for example, the ROM 35, but may be set to be variably adjustable using learning data (described later) generated by a machine learning technique such as deep learning. By making the predetermined period range variably adjustable, the accuracy of determining whether the user U is in a running motion state is further improved.

[0073] In this way, when the BPF·gain setting unit 33 determines that the time difference at which the peaks of the vibration sound are detected is periodic, it sets the gain of the cancellation signal to be suppressed from the audio signal acoustically output from the driver 10, based on the peak Zpeak of the vibration sound. Therefore, in this embodiment, it is possible to efficiently reduce noise such as vibration sound generated in response to the movement of the user U during exercise such as jogging, and suppress deterioration of the sound quality of the sound acoustically output.

[0074] As described above, the headphones 1 (an example of an acoustic device) according to the first embodiment are headphones 1 (an example of an acoustic device) worn by a user U during exercise, and include a driver 10 (an example of a sound emitting unit) that acoustically outputs a sound signal, one acceleration sensor 11 (an example of a sensor) that periodically detects acceleration in three directions, namely, forward / backward, left / right, and up / down directions of the user U, a vibration sound processing unit 32 (an example of a vibration sound peak detection unit) that detects a peak Zpeak of a vibration sound based on the movement of the user U when the detected values ​​of the acceleration in each of the forward / backward, left / right, and up / down directions satisfy a predetermined condition, and a BPF / gain setting unit 33 (an example of a signal processing unit) that determines whether or not the time difference at which the peak Zpeak of the vibration sound is detected is periodic. When it is determined that the time difference at which the peak Zpeak of the vibration sound is detected is periodic, the BPF / gain setting unit 33 sets the gain of a cancellation signal to be suppressed from the sound signal acoustically output from the driver 10 based on the peak Zpeak of the vibration sound.

[0075] Moreover, according to the acoustic control method of the first embodiment, the acoustic control method is a method for headphones 1 (one example of a device) worn by a user U during exercise, and includes a step of acoustically outputting a sound signal (sound emission step), a step of periodically detecting acceleration in three directions of the user U, namely, forward / backward, left / right, and up / down directions, at at least one location (detection step), a step of detecting a peak Zpeak of a vibration sound based on the movement of the user U when the detected values ​​of the acceleration in each of the forward / backward, left / right, and up / down directions satisfy a predetermined condition (vibration sound peak detection step), and a step of determining whether or not the time difference at which the vibration sound peak Zpeak is detected is periodic (signal processing step). In the signal processing step, when it is determined that the time difference at which the vibration sound peak Zpeak is detected is periodic, the gain of a cancellation signal to be suppressed from the sound signal acoustically output in the sound emission step is set based on the vibration sound peak Zpeak.

[0076] When a user U is wearing headphones 1 and engaging in sports, such as jogging or marathon running, jogging is a periodic exercise in which both feet land alternately, so the acceleration sensor 11 detects the periodic impacts caused by the alternating landing of both feet.

[0077] In addition, in the first embodiment, when the BPF / gain setting unit 33 determines that the time difference at which the vibration sound peak Zpeak is detected is periodic, it estimates that a periodic impact occurs due to exercise such as jogging, and sets the gain of a cancellation signal to suppress the impact. Then, based on this gain setting, the ANC unit 42 generates a cancellation signal to suppress the impact from the audio signal acoustically output from the driver 10, and outputs the cancellation signal to the driver 10 via the addition unit 43 and the digital-analog conversion unit 44. This makes it possible to efficiently reduce noise such as vibration sound generated in response to the movement of the user U during exercise, and to suppress deterioration of the sound quality of the acoustically output sound.

[0078] Furthermore, according to the headphones 1 (an example of an audio device) of the first embodiment, the vibration sound processing unit 32 (an example of a vibration sound peak detection unit) detects the vibration sound peak Zpeak when it is determined that the forward / backward speed is greater than the left / right speed and the up / down speed, and the absolute value of the up / down acceleration is greater than the absolute value of the forward / backward acceleration and the absolute value of the left / right acceleration, as the predetermined conditions. Therefore, the vibration sound processing unit 32 can accurately estimate that a periodic impact has occurred in association with exercise such as jogging, and can prevent the noise reduction function from inadvertently operating in situations other than sports such as jogging.

[0079] Furthermore, according to the headphones 1 (an example of an audio device) of the first embodiment, the BPF / gain setting unit 33 (an example of a signal processing unit) specifies the detection time Tzpeak of the vibration sound peak Zpeak when it is determined that the difference between the peak Zpeak of the vibration sound during a predetermined period and the average value Zave of the vibration sound during the predetermined period is greater than the first threshold value TH1 (an example of a first predetermined value) and the differential value ΔZpeak (an example of the amount of change) of the vibration sound peak Zpeak during the predetermined period is greater than the second threshold value TH2 (an example of a second predetermined value). Therefore, it is possible to prevent the BPF / gain setting unit 33 from excessively detecting the detection time of the vibration sound peak Zpeak, thereby preventing the noise reduction function from operating excessively. This makes it possible to reduce noise in a range that is a nuisance to the user U with appropriate sensitivity.

[0080] (Embodiment 2) A second embodiment of the present disclosure will be described with reference to Figures 8 and 9. Note that, since the description of the same or equivalent parts as those in the first embodiment described above will be repeated, the same reference numerals will be used in the drawings and the description may be omitted or simplified.

[0081] [Circuit board configuration] The configuration of the circuit board 20 according to the present embodiment will be described with reference to Fig. 8. Fig. 8 is a functional block diagram illustrating the processing on the circuit board 20 according to the present embodiment. In the description of Fig. 8, the same reference numerals are given to the same configuration as in Fig. 4, and the description is simplified or omitted, and only the different contents will be described.

[0082] In the above-described first embodiment, one acceleration sensor 11 is embedded in only one of the pair of left and right main bodies 3, but in this embodiment, one acceleration sensor is embedded in each of the pair of left and right main bodies 3 (see FIG. 2). That is, the acceleration sensor 11 in this embodiment has a pair of left acceleration sensor 11B (an example of a first sensor) arranged around the left ear of the user U, and a right acceleration sensor 11A (an example of a second sensor) arranged around the right ear of the user U. The left acceleration sensor 11B and the right acceleration sensor 11A are arranged spaced apart from each other in the X-axis direction, and are arranged so as to be able to acquire acceleration for two channels, left and right.

[0083] Corresponding to the embedding of the left acceleration sensor 11B and right acceleration sensor 11A, a pair of a first analog-digital conversion section 41A and a second analog-digital conversion section 41B are provided in the second circuit section 40 of the circuit board 20 as the analog-digital conversion section 41. The first analog-digital conversion section 41A is electrically connected to the left acceleration sensor 11B, and the second analog-digital conversion section 41B is electrically connected to the right acceleration sensor 11A, and converts analog signals of vibration signals (acceleration) for two channels, left and right, into digital signals.

[0084] Furthermore, the first circuit section 30 of the circuit board 20 is provided with a pair of a first LPF section 31A and a second LPF section 31B as the LPF section 31. The first LPF section 31A receives the vibration signal transmitted from the first analog-digital conversion section 41A, passes only the low frequency components of the vibration signal, and transmits it to the vibration sound processing section 32. Similarly, the second LPF section 31B receives the vibration signal transmitted from the second analog-digital conversion section 41B, passes only the low frequency components of the vibration signal, and transmits it to the vibration sound processing section 32 and the ANC section 42. In this way, the vibration sound processing section 32 and the ANC section 42 receive vibration signals for two channels, left and right.

[0085] The vibration sound processing unit 32 receives vibration signals for two channels, left and right, and detects a peak (Zpeak(L) described later) of the vibration sound detected on the left side (an example of a first vibration sound) based on the vibration signal of the left channel (an example of a first detection value) detected by the left acceleration sensor 11B. At the same time, the vibration sound processing unit 32 also detects a peak (Zpeak(R) described later) of the vibration sound detected on the right side (an example of a second vibration sound) based on the vibration signal of the right channel (a second detection value) detected by the right acceleration sensor 11A. The rest of the configuration is the same as that of the circuit board 20 of the first embodiment.

[0086] [Processing flow for circuit boards] Next, a process flow in the circuit board 20 according to the present embodiment will be described with reference to Fig. 9. Fig. 9 is a flow chart illustrating a process flow in the circuit board 20 shown in Fig. 8.

[0087] 9, the circuit board 20 of the headphones 1 determines whether or not the shock cancellation function is turned on in the application of the smartphone P of the user U through wireless communication (S201). If it is determined that the shock cancellation function is not turned on (NO in S201), the process flow ends. On the other hand, if it is determined that the shock cancellation function is turned on (YES in S201), the process flow proceeds to steps S202 and S203.

[0088] Steps S202 and S203 are sub-processes, and the circuit board 20 executes processes similar to steps S102 to S111 in the above-described first embodiment for each of the two left and right channels of vibration signals detected by the left acceleration sensor 11B and the right acceleration sensor 11A, respectively.

[0089] That is, step S202 is a sub-processing for the left channel signal detected by left acceleration sensor 11B, and in step S202, BPF / gain setting unit 33 finally derives a left channel gain (an example of a first gain) (hereinafter also referred to as "Zpeak(L)") for the left channel based on the detection value of the peak of the vibration sound detected on the left side (an example of a first vibration sound).

[0090] Step S203 is a sub-process for the right channel signal detected by the right acceleration sensor 11A, and in step S203, the BPF / gain setting unit 33 also finally derives a right channel gain (an example of a second gain) (hereinafter also referred to as "Zpeak(R)") based on the peak detection value of the vibration sound detected on the right side (an example of a first vibration sound). Steps S202 and S203 are executed simultaneously in parallel, and then the process flow proceeds to step S204.

[0091] The BPF / gain setting unit 33 judges whether the absolute value of the difference between the peak Zpeak(L) of the left channel and the peak Zpeak(R) of the right channel is greater than a third threshold value TH3 (an example of a predetermined value) (S204). If it is judged that the absolute value is greater than the third threshold value TH3 (YES in S204), one of Zpeak(L) and Zpeak(R) is set as the gain of the cancellation signal. Based on this gain setting, the ANC unit 42 generates a cancellation signal for suppression from the audio signal acoustically output from the driver 10, and transmits the cancellation signal to the addition unit 43 (S205).

[0092] At this time, since it is determined that the gain of the vibration signal detected by one of the left acceleration sensor 11B and the right acceleration sensor 11A is excessively high, it is possible to estimate that the user U is in an abnormal state of swaying sideways. In order to notify the user U of the abnormal state and allow him to take appropriate measures, the BPF / gain setting unit 33 displays a warning message indicating that the user U is swaying on the display unit of the smartphone P carried by the user U (S207).

[0093] On the other hand, when it is determined that the difference is not greater than the third threshold value TH3 (NO in S204), that is, when the absolute value of the difference between the peak Zpeak(L) of the left channel and the peak Zpeak(R) of the right channel is determined to be equal to or less than the third threshold value TH3, the BPF·gain setting unit 33 sets the average value of Zpeak(L) and Zpeak(R) as the gain of the cancellation signal. Based on this gain setting, the ANC unit 42 generates a cancellation signal for suppressing from the audio signal acoustically output from the driver 10, and transmits the cancellation signal to the addition unit 43 (S206). Note that, in the present embodiment as well, the third threshold value TH3 is similarly set and stored in advance in, for example, the ROM 35, but may be set so as to be dynamically optimized using learning data (described later) generated by a machine learning technique such as deep learning. By making the third threshold value TH3 dynamically adjustable, the accuracy of estimating that the user U is in an abnormal state where he or she is swaying laterally is further improved.

[0094] As described above, according to the headphones 1 (an example of an acoustic device) of the second embodiment, the acceleration sensor 11 (an example of a sensor) has a left acceleration sensor 11B (an example of a first sensor) arranged around the left ear of the user U, and a right acceleration sensor 11A (an example of a second sensor) arranged around the right ear of the user U. Furthermore, the vibration sound processing unit 32 (an example of a vibration sound peak detection unit) detects a peak of a left-side detected vibration sound (an example of a first vibration sound) based on a vibration signal of the left channel (an example of a first detection value) detected by the left acceleration sensor 11B, and detects a peak of a right-side detected vibration sound (an example of a second vibration sound) based on a vibration signal of the right channel (an example of a second detection value) detected by the right acceleration sensor 11A. In addition, the BPF / gain setting unit 33 (an example of a signal processing unit) derives a peak Zpeak(L) (an example of a first gain) of the left channel based on the detection value of the peak of the vibration sound detected on the left side (an example of a first vibration sound), and derives a peak Zpeak(R) (an example of a second gain) of the right channel based on the detection value of the peak of the vibration sound detected on the right side (an example of the first vibration sound), and when it determines that the difference between the peak Zpeak(L) of the left channel and the peak Zpeak(R) of the right channel is less than or equal to a third threshold TH3 (an example of a predetermined value), it sets the average value of the peak Zpeak(L) of the left channel and the peak Zpeak(R) of the right channel as the gain of the cancellation signal.

[0095] Therefore, left and right acceleration sensors 11B and 11A, which are spaced apart from each other in the horizontal direction (X-axis direction) of user U, acquire signals for two channels, and the gain of the cancellation signal can be set based on the signals for the two channels. This makes it possible to accurately reduce noise such as vibration sounds that occur in response to the movements of user U while exercising.

[0096] Moreover, according to the headphones 1 (an example of an acoustic device) of the second embodiment, the acceleration sensor 11 (an example of a sensor) has a left acceleration sensor 11B (an example of a first sensor) arranged around the left ear of the user U, and a right acceleration sensor 11A (an example of a second sensor) arranged around the right ear of the user U. Moreover, the vibration sound processing unit 32 (an example of a vibration sound peak detection unit) detects a peak of a left-side detected vibration sound (a first vibration sound) based on a vibration signal of a left channel (an example of a first detection value) detected by the left acceleration sensor 11B, and detects a peak of a right-side detected vibration sound (an example of a second vibration sound) based on a vibration signal of a right channel (an example of a second detection value) detected by the right acceleration sensor 11A. In addition, the BPF / gain setting unit 33 (an example of a signal processing unit) derives a peak Zpeak(L) (an example of a first gain) of the left channel based on the detection value of the peak of the vibration sound detected on the left side (an example of a first vibration sound), and derives a peak Zpeak(R) (an example of a second gain) of the right channel based on the detection value of the peak of the vibration sound detected on the right side (an example of the first vibration sound), and when it determines that the difference between the peak Zpeak(L) of the left channel and the peak Zpeak(R) of the right channel is greater than a third threshold value TH3 (an example of a predetermined value), it sets either the peak Zpeak(L) of the left channel or the peak Zpeak(R) of the right channel as the gain of the cancellation signal.

[0097] Therefore, even if it is determined that the level of the vibration signal detected by one of the left acceleration sensor 11B and the right acceleration sensor 11A is excessively high, noise such as vibration sounds generated in response to the movement of the user U during exercise can be reduced without any problems.

[0098] Furthermore, according to the headphones 1 (an example of an audio device) of embodiment 2, the BPF / gain setting unit 33 (an example of a signal processing unit) displays a warning message on a smartphone P (an example of a terminal) carried by the user U to indicate that the user U is staggering.

[0099] When it is determined that the level of the vibration signal detected by one of the left acceleration sensor 11B and the right acceleration sensor 11A is excessively high, it can be estimated that the user U is unsteady. Therefore, by displaying a warning message indicating that the user U is unsteady on the display unit of the smartphone P carried by the user U, the user U can be notified of the abnormal state and can take appropriate measures.

[0100] (Embodiment 3) A third embodiment of the present disclosure will be described with reference to Figures 10 and 11. Note that, since the explanations of the same or equivalent parts as those of the first and second embodiments described above are repeated, the same reference numerals are given to the drawings and the explanations may be omitted or simplified.

[0101] [Circuit board configuration] The configuration of the circuit board 20 according to the present embodiment will be described with reference to Fig. 10. Fig. 10 is a functional block diagram illustrating the processing on the circuit board 20 according to the present embodiment. In the description of Fig. 10, the same reference numerals are given to the same configuration as in Fig. 4, and the description is simplified or omitted, and only the different contents will be described.

[0102] As shown in FIG. 10, in the present embodiment, a case where headphones 1 are used for telephone purposes rather than for music playback is described as one example, and compared to the configuration of circuit board 20 in the above-described second embodiment (see FIG. 8), circuit board 20 in the present embodiment is further provided with a third LPF section 31C and an audio processing section 34 (an example of a speech peak detection section).

[0103] As described above, the bone conduction sensor 9 detects the speech of the user U, and the detection signal is transmitted to the third LPF unit 31C as a speech signal V. The third LPF unit 31C receives the detection signal from the bone conduction sensor 9, passes only the low-frequency components of the detection signal, and transmits it to the voice processing unit 34.

[0104] In this embodiment, the audio processing unit 34 receives the detection signal transmitted from the bone conduction sensor 9 through the third LPF unit 31C, and, based on the reception result, specifies the detection time of the peak of the audio signal detected by the bone conduction sensor 9 when a predetermined condition is satisfied. The audio processing unit 34 transmits the specification result to the BPF / gain setting unit 33. In the present embodiment, the audio processing unit 34 is also provided so as to be able to receive an audio signal from the vibration sound processing unit 32, that is, the vibration sound processing unit 32 is not directly connected to the BPF / gain setting unit 33 but is indirectly connected via the audio processing unit 34. The rest of the configuration is the same as that of the circuit board 20 in the second embodiment.

[0105] [Processing flow for circuit boards] Next, a process flow in the circuit board 20 according to this embodiment will be described with reference to Fig. 11. Fig. 11 is a flow chart illustrating a process flow in the circuit board 20 shown in Fig. 10.

[0106] 11, the circuit board 20 of the headphones 1 determines whether or not the shock cancellation function is turned on in the application of the smartphone P of the user U through wireless communication (S301). If it is determined that the shock cancellation function is not turned on (NO in S301), the process flow ends. On the other hand, if it is determined that the shock cancellation function is turned on (YES in S301), the bone conduction sensor 9 detects the user U's speech and transmits the detection result as a speech signal V to the third LPF unit 31C (S302).

[0107] The third LPF unit 31C receives the speech signal V (audio signal) detected by the bone conduction sensor 9, and sets a cutoff frequency of, for example, 100 Hz to remove high-frequency components of the speech signal V. By this removal, the third LPF unit 31C passes only low-frequency components of the speech signal V (S303).

[0108] The voice processor 34 detects the peak of the speech signal V, and then calculates the difference between the peak Vpeak of the speech signal V (one example of a voice signal) during a predetermined period detected by the bone conduction sensor 9 and the average value Vave of the speech signal V during the predetermined period. The voice processor 34 determines whether this difference is greater than a fourth threshold value TH4 (set to, for example, 6 dB in this embodiment, one example of a third predetermined value). If it is determined that the difference is equal to or less than the fourth threshold value TH4 (NO in S304), the process flow returns to step S302.

[0109] On the other hand, if it is determined that the peak Vpeak of the detected speech signal V is greater than the fourth threshold TH4 (YES in S304), the voice processor 34 differentiates the peak Vpeak of the detected speech signal V and determines whether the differentiation result (differential value ΔVpeak) is greater than a fifth threshold TH5 (set to 3 dB in this embodiment, for example, an example of the fourth predetermined value) (S305). If it is determined that the peak Vpeak is equal to or less than the fifth threshold TH5 (NO in S305), the process flow returns to step S302.

[0110] On the other hand, if it is determined that the differential value ΔVpeak is greater than the fifth threshold TH5 (YES in S305), the voice processor 34 identifies the detection time of the peak of the speech signal V and detects the peak period Tvpeak of the speech signal V (S306).

[0111] In other words, when the voice processing unit 34 determines that the difference between the peak Vpeak of the speech signal V during a specified period detected by the bone conduction sensor 9 and the average value Vave of the speech signal V during the specified period is greater than a fourth threshold value TH4, and the differential value ΔVpeak (an example of the amount of change) of the peak Vpeak of the speech signal V during the specified period is greater than a fifth threshold value TH5, it identifies the detection time of the peak of the speech signal V (S304 to S306).

[0112] After detecting the peak period Tvpeak, the sound processor 34 judges whether the peak period Tvpeak is within a predetermined period range (for example, a period range of 90 to 120 Hz corresponding to the period of running in this embodiment) (S307). If it is judged that the peak period Tvpeak is not within the predetermined period range (NO in S307), the process flow returns to step S302.

[0113] On the other hand, if it is determined that the period is within the predetermined range (S307 NO YES), the BPF / gain setting unit 33 performs low-pass filter processing on the speech signal V in terms of the frequency characteristics of the level of the speech signal V to remove high-frequency components and pass only low-frequency components. After that, the BPF / gain setting unit 33 performs band-pass filter processing on the range including the peak period Tvpeak (S308).

[0114] Furthermore, the BPF / gain setting unit 33 determines whether the absolute value of the difference (an example of the time difference) between the peak period Tzpeak in the Z-axis direction of the vibration sound and the peak period Tvpeak of the speech signal V is less than a sixth threshold value TH6 (for example, 5 Hz in this embodiment, an example of the fifth predetermined value) (S309). If it is determined that the absolute value is equal to or greater than the sixth threshold value TH6 (NO in S309), the process flow returns to step S302.

[0115] On the other hand, when it is determined that the absolute value of the difference between the peak period Tzpeak in the Z-axis direction of the vibration sound and the peak period Tvpeak of the speech signal V is less than the sixth threshold TH6 (YES in S309), the BPF / gain setting unit 33 stops suppressing the speech signal V (END). That is, when the periods of the vibration sound (component in the Z-axis direction) and the speech signal V are similar, the gain of the cancellation signal is not set, and therefore the ANC unit 42 does not generate a cancellation signal. Note that, in the present embodiment as well, the fourth threshold TH4, the fifth threshold TH5, and the sixth threshold TH6 are similarly set and stored in advance in, for example, the ROM 35, but may be set so as to be dynamically optimized using learning data (described later) generated by a machine learning technique such as deep learning. By making the fifth threshold TH5 and the sixth threshold TH6 variably adjustable, the accuracy of suppressing the noise reduction function from operating inadvertently when the user U speaks during exercise is further improved.

[0116] As described above, the headphones 1 (an example of an audio device) of the third embodiment further include a bone conduction sensor 9 (an example of a speech sensor) that detects the speech of the user U, and a sound processing unit 34 (an example of a speech peak detection unit) that specifies the detection time of the peak Vpeak of the speech signal V when it is determined that the difference between the peak Vpeak of the speech signal V (an example of an audio signal) during a predetermined period detected by the bone conduction sensor 9 and the average value Vave of the speech signal V during the predetermined period is greater than a fourth threshold TH4 (an example of a third predetermined value) and the differential value ΔVpeak (an example of an amount of change) of the peak Vpeak of the speech signal V during the predetermined period is greater than a fifth threshold TH5 (an example of a fourth predetermined value). In addition, the BPF / gain setting unit 33 (an example of a signal processing unit) stops suppressing the sound signal when the absolute value (an example of a time difference) of the difference between the peak period Tzpeak (an example of a peak detection time) of the vibration sound in the Z-axis direction and the peak period Tvpeak (an example of a peak detection time) of the speech signal V is less than a sixth threshold TH6 (an example of a fifth predetermined value).

[0117] Therefore, even if the user U speaks while exercising, it is possible to prevent the noise reduction function from operating inadvertently. This allows the user U to talk on the phone through the headphones 1 without any problems.

[0118] (Embodiment 4) A fourth embodiment of the present disclosure will be described with reference to Figures 12 and 13. Note that, since the description of the same or equivalent parts as those of the first to third embodiments described above will be repeated, the same reference numerals will be given to the drawings and the description thereof may be omitted or simplified.

[0119] [Circuit board configuration] The configuration of the circuit board 20 according to the present embodiment will be described with reference to Fig. 12. Fig. 12 is a functional block diagram illustrating the processing on the circuit board 20 according to the present embodiment. In the description of Fig. 12, the same reference numerals are given to the same configuration as in Fig. 4, and the description is simplified or omitted, and only the different contents will be described.

[0120] As shown in FIG. 12, in the present embodiment, an example is described in which headphones 1 are used for music playback rather than for phone calls, and compared to the configuration of circuit board 20 in the above-described second embodiment (see FIG. 8), circuit board 20 in the present embodiment is further provided with a music processing unit 35 (an example of a music peak detection unit).

[0121] The music processing unit 35 receives a music signal transmitted from the smartphone P of the user U via the wireless communication unit of the circuit board 20. That is, the music processing unit 35 inputs a music signal from the smartphone P carried by the user U. Then, based on the reception result, the music processing unit 35 identifies the detection time of the peak of the music signal when a predetermined condition is satisfied.

[0122] Moreover, the music processing unit 35 has a function of a low pass filter, and is provided so as to be able to pass only the low frequency components by removing high frequency components from the components of the music signal it receives. In this embodiment, the music processing unit 35 is provided so as to be able to receive control signals from the vibration sound processing unit 32, that is, the vibration sound processing unit 32 is not directly connected to the BPF / gain setting unit 33, but is indirectly connected via the music processing unit 35. The rest of the configuration is the same as that of the circuit board 20 in the second embodiment.

[0123] [Processing flow for circuit boards] Next, a process flow in the circuit board 20 according to this embodiment will be described with reference to Fig. 13. Fig. 13 is a flow chart illustrating a process flow in the circuit board 20 shown in Fig. 12.

[0124] 13, the circuit board 20 of the headphones 1 determines whether or not the shock cancellation function is turned on in the application of the smartphone P of the user U through wireless communication (S401). If it is determined that the shock cancellation function is not turned on (NO in S401), the processing flow ends. On the other hand, if it is determined that the shock cancellation function is turned on (YES in S301), the music processing unit 35 detects the music signal M wirelessly transmitted from the smartphone P of the user U (S402).

[0125] The music processing unit 35 sets a cutoff frequency of, for example, 100 Hz for the detected music signal M to remove high frequency components of the music signal M. By this removal, the music processing unit 35 passes only low frequency components of the music signal M (S403).

[0126] Furthermore, the music processing unit 35 detects a peak Mpeak of the music signal M, and then calculates the difference between the detected peak Mpeak of the music signal M during a predetermined period and the average value Mave of the music signal M during the predetermined period. The music processing unit 35 determines whether this difference is greater than a seventh threshold TH7 (set to, for example, 6 dB in this embodiment, an example of the third predetermined value). If it is determined that the difference is equal to or less than the seventh threshold TH7 (NO in S404), the process flow returns to step S402.

[0127] On the other hand, if it is determined that the peak Mpeak is greater than the seventh threshold TH7 (YES in S404), the music processing unit 35 differentiates the detected peak Mpeak of the music signal M and determines whether the differentiation result (differential value ΔMpeak) is greater than an eighth threshold TH8 (set to, for example, 3 dB in this embodiment, an example of the fourth predetermined value) (S405). If it is determined that the peak Mpeak is equal to or less than the eighth threshold TH8 (NO in S405), the process flow returns to step S402.

[0128] On the other hand, if it is determined that the differential value ΔMpeak is greater than the eighth threshold TH8 (YES in S405), the music processing unit 35 identifies the detection time of the peak of the music signal M and detects the peak period Tmpeak of the music signal M (S406).

[0129] In other words, the music processing unit 35 inputs a music signal M from a smartphone P carried by a user U, and when it determines that the difference between the peak Mpeak of the music signal M during a specified period and the average value Mave of the music signal M during the specified period is greater than a seventh threshold TH7 and that the differential value ΔMpeak of the peak Mpeak of the music signal M during the specified period is greater than an eighth threshold TH8, it identifies the detection time of the peak Mpeak of the music signal M (S404 to S406).

[0130] After detecting the peak period Tmpeak, the sound processor 34 judges whether the peak period Tmpeak is within a predetermined period range (for example, a period range of 90 to 120 Hz corresponding to the period of running in this embodiment) (S407). If it is judged that the peak period Tmpeak is not within the predetermined period range (NO in S407), the process flow returns to step S402.

[0131] On the other hand, if it is determined that the peak period Tmpeak is within the predetermined period range, the BPF / gain setting unit 33 performs low-pass filter processing on the music signal M to remove high-frequency components and pass only low-frequency components, in terms of the frequency characteristics of the level related to the music signal M. Thereafter, the BPF / gain setting unit 33 performs band-pass filter processing on the range including the peak period Tmpeak (S408).

[0132] Furthermore, the BPF / gain setting unit 33 judges whether or not the absolute value of the difference (an example of the time difference) between the peak period Tzpeak in the Z-axis direction of the vibration sound and the peak period Tmpeak of the music signal M is less than a ninth threshold TH9 (for example, 5 Hz in this embodiment, an example of the fifth predetermined value) (S409). If it is judged that the absolute value is equal to or greater than the ninth threshold TH9 (NO in S409), the process flow returns to step S402.

[0133] On the other hand, if it is determined that the absolute value of the difference between the peak period Tzpeak in the Z-axis direction of the vibration sound and the peak period Tmpeak of the music signal M is less than the ninth threshold TH9 (YES in S409), the BPF / gain setting unit 33 reduces the gain of the cancellation signal by a predetermined value (for example, 3 dB in this embodiment, an example of the sixth predetermined value) (S410). That is, when the periods of the vibration sound (component in the Z-axis direction) and the music signal M are similar, the gain of the cancellation signal is reduced and set, and the ANC generates the cancellation signal with the reduced and set gain. Note that, in this embodiment as well, the seventh threshold TH7, the eighth threshold TH8, and the ninth threshold TH9 are similarly set and stored in advance in, for example, the ROM 35, but may be set so as to be dynamically optimized using learning data (described later) generated by a machine learning technique such as deep learning. By making the third threshold TH3 variably adjustable, the accuracy of suppressing the noise reduction function from operating excessively (being too effective) is further improved even when the user U plays music while exercising.

[0134] As described above, the headphones 1 (an example of an audio device) of the fourth embodiment further include a music processing unit 35 (an example of a music peak detection unit) that inputs a music signal M from a smartphone P (an example of a terminal) held by a user U, and specifies a detection time of the peak Mpeak of the music signal M when it is determined that a difference between a peak Mpeak of the music signal M during a predetermined period and an average value Mave of the music signal M during the predetermined period is greater than a seventh threshold TH7 (an example of a third predetermined value) and a differential value ΔMpeak of the peak Mpeak of the music signal M during the predetermined period is greater than an eighth threshold TH8 (an example of a fourth predetermined value). In addition, the BPF / gain setting unit 33 (an example of a signal processing unit) reduces the gain of the cancellation signal by a predetermined value (an example of a sixth predetermined value) when an absolute value (an example of a time difference) of a difference between a peak period Tzpeak of the vibration sound (an example of a peak detection time) and a peak period Tmpeak of the music signal M (an example of a peak detection time) is less than a ninth threshold TH9 (an example of a fifth predetermined value).

[0135] Therefore, even if the user U plays music while exercising, the noise reduction function can be prevented from operating excessively (being too effective), allowing the user U to listen to music through the headphones 1 without any problems.

[0136] As described above, when all or some of the first threshold TH1, second threshold TH2, and predetermined periodic range in embodiment 1, the third threshold TH3 in embodiment 2, the fourth threshold TH4, fifth threshold TH5, and sixth threshold TH6 in embodiment 3, and the seventh threshold TH7, eighth threshold TH8, and ninth threshold TH9 in embodiment 4 are variably adjustable using learning data generated by a machine learning technique such as deep learning, the learning for generating each learning data may be performed using one or more statistical classification techniques. Examples of statistical classification techniques include linear classifiers, support vector machines, quadratic classifiers, kernel density estimation, decision trees, artificial neural networks, Bayesian techniques and / or networks, hidden Markov models, binary classifiers, multi-class classifiers, a clustering technique, a random forest technique, a logistic regression technique, a linear regression technique, a gradient boosting technique, and the like. However, the statistical classification techniques used are not limited to these. Furthermore, the learning data may be generated by a processing unit in a smartphone P, which is an example of a device with which the headphones 1 communicate wirelessly, or may be generated by a server device connected to the smartphone P via a network, for example. This makes it possible for each threshold value and / or the predetermined period range to be adjusted to suit the user U who uses the headphones 1.In addition, adjustments can be made in accordance with changes in the state in which the user U is using the headphones 1 and changes in the situation around the user U.

[0137] Although several embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications, corrections, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure. In addition, the components in the above-mentioned embodiments may be arbitrarily combined within the scope of the invention.

[0138] For example, as the acceleration sensor 11 in the first embodiment and the acceleration sensors in the second and third embodiments (for example, the right acceleration sensor 11A and the left acceleration sensor 11B), an acceleration sensor (three-axis acceleration sensor) capable of periodically detecting vibration components (accelerations) in three axial directions consisting of the up-down direction (vertical direction according to gravity (Z-axis direction)), the front-back direction (Y-axis direction), and the left-right direction (X-axis direction) of the user U is used. The present disclosure may use an acceleration sensor (six-axis acceleration sensor) capable of periodically detecting accelerations in six axial directions, which are obtained by adding sway components (accelerations) in three axial directions consisting of the rotation direction around the X-axis, the rotation direction around the Y-axis, and the rotation direction around the Z-axis (i.e., "yaw-pitch-roll") to the vibration components (accelerations) in the three axial directions. By using such a six-axis acceleration sensor, it is possible to further improve the accuracy of determining whether the user U is in a running motion state and the accuracy of detecting the user's sway, and it is also possible to utilize it for posture advice to sports athletes. [Industrial Applicability]

[0139] The present disclosure is useful as an acoustic device and an acoustic control method that can efficiently reduce noise such as vibration noise generated in response to a user's movements during exercise such as jogging, and suppress deterioration in the sound quality of sound that is acoustically output. [Explanation of symbols]

[0140] 1. Headphones (an example of audio equipment) 2 Headband 3 Main body 4. Housing 5 Opening 6 Partition 7 Ear pads 8A Internal Microphone 8B External microphone 8C Speech microphone 9 Bone conduction sensor (an example of a speech sensor) 10 Driver (an example of a sound output section) 11 Acceleration sensor (example of sensor) 11A right side acceleration sensor 11B Left acceleration sensor 20 Circuit Board 30 1st circuit section 31 LPF section 31A 1st LPF section 31B 2nd LPF section 31C 3rd LPF section 32 Vibration sound processing unit (an example of a vibration sound peak detection unit) 33 BPF / Gain setting section (an example of a signal processing section) 34 Voice processing unit (an example of a speech peak detection unit) 35 Music processing section (an example of a music peak detection section) 40 Second circuit section 41 Analog-to-digital converter 41A First analog-to-digital converter 41B Second analog-to-digital converter 42 ANC Department 43 Addition section 44 Digital-to-analog converter 45 Amplifier section P Smartphone

Claims

1. 1. An audio device worn by a user during exercise, comprising: A sound output unit that acoustically outputs a sound signal; The acceleration of the user in three directions, namely, forward / backward, left / right, and up / down directions, is periodically detected. At least one sensor for outputting a a vibration sound peak detection unit that detects a peak of a vibration sound based on a movement of the user when a detection value of the acceleration in each of the forward / backward direction, the left / right direction, and the up / down direction satisfies a predetermined condition; a signal processing unit that determines whether or not the time difference at which the peak of the vibration sound is detected is periodic; When it is determined that the time difference at which the peak of the vibration sound is detected is periodic, the signal processing unit sets a gain of a cancellation signal to be suppressed from the sound signal acoustically output from the sound emitting unit based on a level of the peak of the vibration sound. sound equipment.

2. the vibration sound peak detection unit detects the peak of the vibration sound when it determines, as the predetermined condition, that the velocity in the forward / backward direction is greater than the velocity in the left / right direction and the velocity in the up / down direction and that the absolute value of the acceleration in the up / down direction is greater than the absolute value of the acceleration in the forward / backward direction and the absolute value of the acceleration in the left / right direction.

2. An acoustic device according to claim 1.

3. the signal processing unit, when determining that a difference between a peak of the vibration sound during a predetermined period and an average value of the vibration sound during the predetermined period is greater than a first predetermined value and that an amount of change in the peak of the vibration sound during the predetermined period is greater than a second predetermined value, specifies a detection time of the peak of the vibration sound.

2. An acoustic device according to claim 1.

4. the sensors include a first sensor disposed around a left ear of the user and a second sensor disposed around a right ear of the user; the vibration sound peak detection unit detects a peak of a first vibration sound based on a first detection value detected by the first sensor, and detects a peak of a second vibration sound based on a second detection value detected by the second sensor, the signal processing unit derives a first gain based on a detection value of a peak level of the first vibration sound, and derives a second gain based on a detection value of a peak level of the second vibration sound, and when it is determined that a difference between the first gain and the second gain is equal to or smaller than a predetermined value, sets an average value of the first gain and the second gain as a gain of the cancellation signal.

2. An acoustic device according to claim 1.

5. the sensors include a first sensor disposed around a left ear of the user and a second sensor disposed around a right ear of the user; the vibration sound peak detection unit detects a peak of a first vibration sound based on a first detection value detected by the first sensor, and detects a peak of a second vibration sound based on a second detection value detected by the second sensor, the signal processing unit derives a first gain based on a detection value of a peak level of the first vibration sound, and derives a second gain based on a detection value of a peak level of the second vibration sound, and when it is determined that a difference between the first gain and the second gain is greater than a predetermined value, sets one of the first gain and the second gain as a gain of the cancellation signal.

2. An acoustic device according to claim 1.

6. The signal processing unit displays a warning message on a terminal carried by the user, the warning message indicating that the user is wandering.

6. An acoustic device according to claim 5.

7. A speech sensor for detecting the user's speech; a speech peak detection unit that, when it is determined that a difference between a peak of the audio signal during a predetermined period detected by the speech sensor and an average value of the audio signal during the predetermined period is greater than a third predetermined value and an amount of change in the peak of the audio signal during the predetermined period is greater than a fourth predetermined value, identifies a detection time of the peak of the audio signal, The signal processing unit stops suppressing the sound signal when a time difference between a detection time of a peak of the vibration sound and a detection time of a peak of the audio signal is less than a fifth predetermined value.

2. An acoustic device according to claim 1.

8. a music peak detection unit that inputs a music signal from a terminal carried by the user, and identifies a detection time of the peak of the music signal when it is determined that a difference between a peak of the music signal during a predetermined period and an average value of the music signal during the predetermined period is greater than a third predetermined value and an amount of change in the peak of the music signal during the predetermined period is greater than a fourth predetermined value, the signal processing unit reduces a gain of the cancellation signal by a sixth predetermined value when a time difference between a detection time of a peak of the vibration sound and a detection time of a peak of the music signal is less than a fifth predetermined value; 2. An acoustic device according to claim 1.

9. 1. A sound control method performed by a sound device worn by a user during exercise, comprising: acoustically outputting a sound signal; detecting acceleration of the user in three directions, i.e., forward / backward, left / right, and up / down directions, periodically at at least one location; detecting a peak of a vibration sound based on a movement of the user when the detected values ​​of acceleration in each of the forward / backward direction, the left / right direction, and the up / down direction satisfy a predetermined condition; and determining whether or not the time difference at which the peak of the vibration sound is detected is periodic. when it is determined that the time difference at which the peak of the vibration sound is detected is periodic, a gain of a cancellation signal to be suppressed from the sound signal acoustically output is set based on a level of the peak of the vibration sound. Acoustic control methods.

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