Audio equipment

Abstract

To provide an acoustic device capable of accurately estimating a sound source direction.SOLUTION: An acoustic device is provided, including: a plurality of microphones 210, 220, 230, 240 arranged in such a manner that the directivities thereof are different from each other; a calculation section 310 acquiring signals 500 input to two of the microphones and calculating an amplitude ratio R from the amplitudes of the signals; a storage section 320 stored with correspondence relationship information related to correspondence relationship between an angle θ indicating the directions of sound sources 1000, 2000 with respect to the microphones and the amplitude ratio R; and an estimation section 330 estimating the angle from the amplitude ratio based on the correspondence relationship information.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The disclosure herein relates to an audio device that includes a microphone. [Background technology]

[0002] Patent Document 1 describes a directional acoustic sensor having two resonant units with different directivities and a signal processing unit that adjusts the directional characteristics by calculating the sum or difference of an arbitrary ratio of the outputs of the two resonant units. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-2826 Summary of the Invention [Problem to be solved by the invention]

[0004] The directional acoustic sensor described in Patent Document 1 is capable of selectively acquiring only the sound signal from a desired direction by adjusting the directional characteristics to the desired direction.

[0005] However, it is difficult to accurately estimate the direction of the sound source by the sum or difference of the outputs of the two resonator units, which makes it difficult to selectively obtain only the sound signal from the desired direction.

[0006] Therefore, an object of the present disclosure is to provide an acoustic device that can estimate the direction of a sound source with high accuracy. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, an audio device includes: A plurality of microphones (210, 220, 230, 240) arranged so as to have different directivities from each other; A calculation unit (310) that acquires signals (500) input to two of the multiple microphones and calculates an amplitude ratio from the amplitudes of the signals; A storage unit (320) storing correspondence information relating to a correspondence relationship between an angle (θ) indicating a direction of a sound source (1000, 2000) relative to a plurality of microphones and an amplitude ratio (R); An estimation unit (330) that estimates an angle from an amplitude ratio based on the correspondence relationship information; death, The calculation unit calculates the delay time, which is the difference in signal acquisition time that occurs based on the difference in distance to the sound source of the two microphones, the storage unit stores first data (610) which is correspondence information, second data (620) relating to the correspondence between the delay time and the angle, third data (630) which represents a transition of a first amount of change in the angle per unit amplitude ratio, and fourth data (640) which represents a transition of a second amount of change in the angle per unit delay time; The estimation unit estimates the angle from the first data or the second data, which corresponds to the smaller amount of change between the first amount of change and the second amount of change. .

[0008] This makes it possible to estimate the sound source direction with high accuracy.

[0009] It should be noted that the reference numbers in parentheses above merely indicate the corresponding relationship with the configurations described in the embodiments described below, and do not in any way limit the technical scope. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing a state in which an audio device is mounted on a vehicle. [Diagram 2] 13 is a diagram illustrating an example of a result of measuring microphone directivity. [Diagram 3] 1 is a diagram showing an electrical connection configuration of an audio device. [Figure 4] 4 is a diagram for explaining a method of calculating an amplitude ratio R. [Diagram 5] 4 is a diagram for explaining a method of calculating an amplitude ratio R. [Figure 6] 1 is a diagram showing first data. [Figure 7] 13 is a diagram illustrating a flow of estimating a sound source direction from an amplitude ratio R. [Figure 8] 1 is a diagram for explaining a method of calculating a delay time τ. [Figure 9] 1 is a diagram for explaining a method of calculating a delay time τ. [Figure 10] 1 is a diagram showing first data and second data. [Figure 11] 13 is a diagram showing third and fourth data. [Figure 12] 1 is a diagram for explaining a flow of estimating a sound source direction from an amplitude ratio R or a delay time τ. [Figure 13] 1 is a diagram illustrating an audio device having a plurality of sound sources. [Figure 14] 1 is a diagram showing an electrical connection configuration of an audio device. [Figure 15] 1 is a diagram for explaining a signal based on a voice in a direction A and a signal based on a voice in a direction B. [Figure 16] 13 is a diagram for explaining a method for removing a signal based on audio in direction B. [Figure 17] 13 is a diagram illustrating a modified example of estimating a sound source direction. [Figure 18] 13 is a diagram illustrating a modified example of estimating a sound source direction. [Figure 19] 13 is a diagram illustrating a modified example of estimating a sound source direction. [Figure 20] 13 is a diagram illustrating a modified example of estimating a sound source direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be used to designate parts corresponding to matters described in the preceding embodiment, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, the other embodiment described previously may be applied to the other parts of the configuration.

[0012] In addition to combinations of parts that are explicitly stated as possible in each embodiment, it is also possible to partially combine embodiments, embodiments and variations, and variations even if not explicitly stated, provided that there are no particular problems with the combination.

[0013] The embodiments described below are merely examples for the purpose of explanation, and the present invention is not limited to the embodiments described below.

[0014] (First embodiment) An acoustic device 100 will be described with reference to Fig. 1 to Fig. 7. In the following description, three mutually orthogonal directions will be referred to as x-direction, y-direction, and z-direction. In the drawings, the description of "direction" is omitted, and the directions are simply written as x, y, and z.

[0015] <Sound equipment> 1, the audio device 100 includes a plurality of microphones 200, a control unit 300, and a package 400. The plurality of microphones 200 and the control unit 300 are electrically connected. The plurality of microphones 200 and the control unit 300 are provided in the package 400.

[0016] Each of the multiple microphones 200 has a directivity as shown in Fig. 2. Directivity is a polar coordinate representation of the sensitivity of the microphone 200 relative to the direction of a sound source. Note that in Fig. 1, the directivity corresponding to each of the multiple microphones 200 is shown by dashed lines around each of the multiple microphones 200.

[0017] When air vibrations (sound) occur in the external space, the vibrations act as acoustic pressure on the multiple microphones 200. The multiple microphones 200 output electrical signals to the control unit 300 according to the acoustic pressure.

[0018] In this embodiment, each of the multiple microphones 200 outputs an electrical signal corresponding to the sound 1100 generated from the sound source 1000 to the control unit 300. The electrical signal input from the multiple microphones 200 to the control unit 300 is hereinafter referred to as a signal 500. In this manner, the sound 1100 generated from the sound source 1000 is input to the control unit 300 as the signal 500.

[0019] <Package> 1 shows a plan view of the acoustic device 100 as seen from the z direction. The package 400 is substantially in the shape of a triangular prism. The package 400 is mounted, for example, on the instrument panel of a vehicle, with its hypotenuses facing specific directions A and B. Here, direction A is, for example, the driver's seat, and direction B is, for example, the passenger seat.

[0020] <Microphone> The multiple microphones 200 include a first microphone 210 and a second microphone 220. The first microphone 210 is disposed on one of two sloping surfaces of the package 400. The second microphone 220 is disposed on the other of the two sloping surfaces of the package 400.

[0021] 1, the first microphone 210 and the second microphone 220 are arranged side by side and spaced apart in the x direction. In this embodiment, the first microphone 210 and the second microphone 220 are arranged symmetrically with respect to a central plane 11 that passes through the centers of the first microphone 210 and the second microphone 220.

[0022] The first microphone 210 is provided on one of the inclined surfaces of the package 400 so that the angle between the central surface 11 and the first microphone 210 is φ1. Similarly, the second microphone 220 is provided on the other of the inclined surfaces of the package 400 so that the angle between the central surface 11 and the second microphone 220 is φ2. The angle φ obtained by combining the angles φ1 and φ2 corresponds to the predetermined angle. In this embodiment, a form in which the angles φ1 and φ2 are equal will be described, but the angles φ1 and φ2 may be different.

[0023] In this embodiment, the first microphone 210 and the second microphone 220 each have the same directivity as a single unit. Note that the directivity of the first microphone 210 and the directivity of the second microphone 220 may be different.

[0024] In this embodiment, as shown in FIG. 1, first microphone 210 and second microphone 220 are provided on one and the other of two oblique sides of package 400, so that first microphone 210 and second microphone 220 have different directivities.

[0025] <Control Unit> 1, the control unit 300 is mounted in a package 400. Although the drawing shows a form in which the control unit 300 is mounted in the center of the package 400 for the sake of convenience, the mounting position of the control unit 300 on the package 400 is not limited.

[0026] As shown in FIG. 3, the control unit 300 includes a calculation unit 310, a storage unit 320, and an estimation unit 330.

[0027] <Arithmetic section> The calculation unit 310 has a function of calculating a physical quantity from a signal 500 based on the voice 1100 input to the first microphone 210 and a signal 500 based on the voice 1100 input to the second microphone 220. For ease of explanation below, the signal 500 based on the voice 1100 input to the first microphone 210 will be referred to as a first signal 510. The signal 500 based on the voice 1100 input to the second microphone 220 will be referred to as a second signal 520. Hereinafter, the first signal 510 and the second signal 520 will be referred to as the signal 500 without distinction as necessary.

[0028] The upper part of Fig. 4 shows a waveform representing the first signal 510. The lower part of Fig. 4 shows a waveform representing the second signal 520. The calculation unit 310 is configured to perform the following calculation on the signal 500 that is equal to or greater than the threshold value.

[0029] The calculation unit 310 calculates the amplitude ratio R between the amplitude A of the first signal 510 and the amplitude B of the second signal 520 as a physical quantity. The amplitude A is the amount of displacement from a reference where the intensity is 0 to the maximum intensity in the positive direction as shown in Fig. 4. The amplitude B is the amount of displacement from a reference where the intensity is 0 to the maximum intensity in the positive direction as shown in Fig. 4. Note that the amount of displacement from a reference where the intensity is 0 to the maximum intensity in the negative direction may be applied to the amplitude A and the amplitude B.

[0030] 4, the amplitude ratio R is calculated by dividing the amplitude A of the first signal 510 by the amplitude B of the second signal 520. The amplitude ratio R may also be calculated by dividing the amplitude B of the second signal 520 by the amplitude A of the first signal 510.

[0031] Further, since the detailed definitions of the amplitude A of the first signal 510 and the amplitude B of the second signal 520 differ depending on the calculation method, they will be explained together with the specific calculation method of the amplitude ratio R.

[0032] There are two possible calculation methods. One is to calculate the amplitude ratio R by comparing the largest amplitudes of the signals 500 that are equal to or greater than the threshold. As described above, in the case of FIG. 4, the amplitude ratio R is calculated by dividing the amplitude A of the first signal 510 by the amplitude B of the second signal 520.

[0033] Another method is to obtain the cross-correlation function of the first signal 510 and the second signal 520, and calculate the amplitude ratio R at the time shift amount at which the correlation is maximized, as shown in Fig. 5. Specifically, the amplitude ratio R is calculated by comparing the amplitudes at the same time points after the cross-correlation is maximized. In Fig. 5, the amplitude ratio R is calculated by dividing the amplitude C of the first signal 510 by the amplitude D of the second signal 520.

[0034] The calculation unit 310 may use either of the above-mentioned two methods, or a different method, to calculate the amplitude ratio R. The cross-correlation function will be described later.

[0035] <Storage section> The storage unit 320 has data for estimating the direction of a sound source. In the following description, for ease of explanation, the first microphone 210 and the second microphone 220 are referred to as the microphone 200 without distinction as necessary.

[0036] A parameter indicating the sound source direction is the sound source direction angle θ. In this embodiment, the sound source direction angle θ is the angle between the direction of the sound from the sound source 1000 toward the microphone 200 and the reference plane 10 that passes through the center of the microphone 200 and is aligned with the y-axis. The sound source direction angle θ corresponds to an angle.

[0037] The reference plane 10 in this embodiment is a plane obtained by translating a center plane 11 toward the microphone 200, where the amplitudes of the signals 500 entering each of the multiple microphones 200 are equal and no delay time occurs.

[0038] In this embodiment, the angle φ1 between the center plane 11 and the first microphone 210 is equal to the sound source direction angle θ. The angle φ2 between the center plane 11 and the second microphone 220 is equal to the sound source direction angle θ. The angles φ1, φ2, and the sound source direction angle θ do not have to be equal.

[0039] As data for estimating the sound source direction angle θ, the storage unit 320 has first data 610, which is correspondence information indicating the correspondence between the amplitude ratio R and the sound source direction angle θ as shown in FIG.

[0040] The first data 610 is a continuous function as shown in Fig. 6. However, the first data 610 does not have to be a continuous function. The first data 610 may be a discrete data table.

[0041] Furthermore, the calculation unit 310 may standardize the amplitude ratio R by dividing it by the maximum expected amplitude ratio R, and the correspondence relationship between the normalized amplitude ratio R and the sound source direction angle θ may be stored in the first data 610.

[0042] <Estimation part> The estimation unit 330 has a function of estimating the sound source direction angle θ from the amplitude ratio R based on the first data 610.

[0043] <Sound source direction estimation using amplitude ratio> Below is a flowchart of the control unit 300. Note that, although each step will be described below as a function of each functional unit of the calculation unit 310 to the estimation unit 330, each step may be considered to be performed by the control unit 300 since the control unit 300 includes the calculation unit 310 to the estimation unit 330.

[0044] As shown in FIG. 7, when a first signal 510 and a second signal 520 are sent from the first microphone 210 and the second microphone 220 to the calculation unit 310, the calculation unit 310 performs a process of acquiring a signal 500 in step S710.

[0045] After the calculation unit 310 acquires the signal 500 in step S710, the calculation unit 310 then calculates the amplitude ratio R between the amplitude of the first signal 510 and the amplitude of the second signal 520 in step S720.

[0046] After the calculation unit 310 calculates the amplitude ratio R in step S720, the estimation unit 330 estimates the sound source direction angle θ in step S730. As a method of estimating the sound source direction angle θ, the estimation unit 330 estimates the sound source direction by reading the sound source direction angle θ corresponding to the amplitude ratio R based on the first data 610 stored in the storage unit 320.

[0047] <Action and effect> As described above, the estimation unit 330 estimates the sound source direction by reading the sound source direction angle θ corresponding to the amplitude ratio R based on the first data 610. Also, as described above, the first data 610 is a continuous function. This enables the acoustic device 100 to estimate the sound source direction with high accuracy.

[0048] As described above, first microphone 210 and second microphone 220 each have the same directivity as a single unit. By providing first microphone 210 and second microphone 220 on one and the other of the two oblique side portions of package 400, first microphone 210 and second microphone 220 each have different directivities. This prevents the number of types of microphones 200 from increasing.

[0049] Second embodiment In the first embodiment, a description has been given of a mode in which the acoustic device 100 estimates the sound source direction based on the amplitude ratio R and the first data 610. However, the acoustic device 100 may estimate the sound source direction based on a delay time τ (described later), a change amount in the first data 610, and a change amount in the second data 620 (described later). Details of the second embodiment will be described below.

[0050] <Delay time> In addition to the amplitude ratio R described above as a physical quantity, the calculation unit 310 calculates the delay time τ between the signals 500. The delay time τ between the signals 500 is the difference in signal acquisition time that occurs based on the difference in distance between the first microphone 210 and the second microphone 220 and the sound source 1000. A method for calculating the delay time τ will be specifically described below.

[0051] There are, for example, two possible calculation methods. One is a method of calculating the difference between time T1 of first signal 510 and time T2 of second signal 520 when the amplitude is the largest as shown in FIG.

[0052] Another method is to obtain a cross-correlation function between a first signal 510 and a second signal 520, and calculate the time shift amount at which the cross-correlation is maximized as the delay time τ, as shown in Fig. 9. Note that the calculation unit 310 may use either method or another method to calculate the delay time τ.

[0053] The calculation unit 310 also standardizes the calculated delay time τ by dividing it by the expected maximum delay time τ. The second data 620 described later stores correspondence relationship information indicating the correspondence relationship between the normalized delay time τ and the sound source direction angle θ.

[0054] <Cross-correlation function> Cross-correlation function φ when a signal function x(t) is shifted by a time τ from another signal function y(t) xy (τ) can be expressed as follows:

[0055]

number

[0056] For discrete values ​​sampled at a certain sampling period, the cross-correlation function φ xy For example, the cross-correlation function φ when the time is shifted by j in a total of M intervals is xy (j) can be expressed as follows:

[0057]

number

[0058] <Second Data> In addition to the first data 610 indicating the correspondence between the amplitude ratio R and the sound source direction angle θ described above, the storage unit 320 has second data 620 indicating the correspondence between the delay time τ and the sound source direction angle θ as shown in Fig. 10. The first data 610 stores the correspondence between the normalized amplitude ratio R and the sound source direction angle θ. The second data 620 stores the correspondence between the normalized delay time τ and the sound source direction angle θ. Hereinafter, the normalized amplitude ratio R and the normalized delay time τ will be simply referred to as the amplitude ratio R and the delay time τ.

[0059] <Third and fourth data> Furthermore, the storage unit 320 stores third data 630 indicating the transition of the amount of change in the sound source direction angle θ per unit amplitude ratio, and fourth data 640 indicating the transition of the amount of change in the sound source direction angle θ per unit delay time, as shown in Fig. 11. Hereinafter, the amount of change in the sound source direction angle θ per unit amplitude ratio will be referred to as the first amount of change, and the amount of change in the sound source direction angle θ per unit delay time will be referred to as the second amount of change.

[0060] In other words, the correspondence relationship between the amplitude ratio R and the first change amount is stored in the third data 611. The correspondence relationship between the delay time τ and the second change amount is stored in the fourth data 612. Note that in Fig. 11, the amplitude ratio R and the delay time τ are shown as input values.

[0061] The third data 611 is a function obtained by differentiating the first data 610 with respect to the amplitude ratio R. The fourth data 621 is a function obtained by differentiating the second data 620 with respect to the delay time τ.

[0062] <Selection and Estimation> The estimation unit 330 has a function of estimating the sound source direction angle θ from the amplitude ratio R based on the first data 610 described above, as well as a function of estimating the sound source direction angle θ from the delay time τ based on the second data 620.

[0063] Furthermore, the estimation unit 330 selects the smaller amount of change between the first amount of change and the second amount of change, and has a function of estimating the sound source direction angle θ from the original data before differentiation of the selected amount of change with the smaller amount of change.

[0064] The original data of the third data 611 refers to the first data 610. The original data of the fourth data 621 refers to the second data 620.

[0065] <Sound source direction estimation using amplitude ratio or delay time> As shown in FIG. 12, when a first signal 510 and a second signal 520 are sent from the first microphone 210 and the second microphone 220 to the calculation unit 310, the calculation unit 310 performs a process of acquiring a signal 500 in step S810.

[0066] After the calculation unit 310 acquires the signal 500 in step S810, the calculation unit 310 then calculates the amplitude ratio R in step S820.

[0067] Next, in step S830, the calculation unit 310 performs a calculation process to calculate the delay time τ. Note that steps S820 and S830 may be performed simultaneously. The order of steps S820 and S830 may be reversed.

[0068] In step S840, the amplitude ratio R is input as an input value to the estimation unit 330. Then, the estimation unit 330 reads out the first amount of change corresponding to the amplitude ratio R based on the third data 630 stored in the storage unit 320.

[0069] In step S850, the delay time τ is input as an input value to the estimation unit 330. Then, the estimation unit 330 reads the second amount of change corresponding to the delay time τ based on the fourth data 640 stored in the storage unit 320.

[0070] Note that steps S840 and S850 may be performed simultaneously, or the order of steps S840 and S850 may be reversed.

[0071] Then, in step S860, the estimation unit 330 compares the first change amount with the second change amount, and in step S870, the estimation unit 330 selects the smaller change amount between the first change amount and the second change amount.

[0072] In step S880, the estimation unit 330 estimates the sound source direction angle θ based on the original data that is the smaller of the first change amount and the second change amount.

[0073] This makes it possible to estimate the sound source direction with high accuracy from the first data 610 and the second data 620. The deviation of the estimated sound source direction tends to become small.

[0074] Third embodiment Additionally, the acoustic device 100 may have a command section 340 and a removal section 350. The command section 340 and the removal section 350 will be described below.

[0075] The instruction unit 340 stores, for example, an instruction to remove the signal 500 input from a position other than the driver's seat among the signals 500 input to the microphone 200. The signal 500 input from a position other than the driver's seat includes, for example, the signal 500 input from the passenger seat.

[0076] The removal unit 350 has a function of removing signals 500 input from a specific direction from among the signals 500 input to the microphone 200 based on an instruction from the instruction unit 340. The removal unit 350 removes signals 500 from a specific direction by performing an operation on the signals 500 from the specific direction input to the multiple microphones 200. Details will be described later.

[0077] 13, when sounds 1100 and 2100 are emitted from the sound source 1000 on the driver's seat side and the sound source 2000 on the passenger's seat side, respectively, a first signal 510 and a second signal 520 based on the sounds 1100 and 2100 are input to the first microphone 210 and the second microphone 220, respectively. The sounds 1100 and 2100 shown here refer to the sound 1100 emitted from the sound source 1000 on the driver's seat side and the sound 2100 emitted from the sound source 2000 on the passenger's seat side. Note that the sound 1100 emitted from the sound source 1000 on the driver's seat side may be, for example, the driver's speech. The sound 2100 emitted from the sound source 2000 on the passenger's seat side may be, for example, the passenger's speech.

[0078] 14, the acoustic device 100 estimates the sound source direction of each of the signals 500 input from multiple directions according to the flowchart described above. As a result, the calculation unit 310 estimates that, for example, sound sources 1000 and 2000 are located on the driver's seat side and the passenger's seat side, respectively.

[0079] Hereinafter, for ease of explanation, the driver's side signal 500 included in the first signal 510 will be referred to as a first driver's side signal 511. The passenger's side signal 500 included in the first signal 510 will be referred to as a first passenger's side signal 512. The driver's side signal 500 included in the second signal 520 will be referred to as a second driver's side signal 521. The passenger's side signal 500 included in the second signal 520 will be referred to as a second passenger's side signal 522.

[0080] 15, second driver's side signal 521 is input to calculation unit 310 with a delay of delay time τ from first driver's side signal 511. First passenger's side signal 512 is input to calculation unit 310 with a delay of delay time τ from second passenger's side signal 522.

[0081] The amplitude of the second driver's side signal 521 is smaller than the amplitude of the first driver's side signal 511. The amplitude of the first passenger's side signal 512 is smaller than the amplitude of the second passenger's side signal 522.

[0082] When an instruction to remove signal 500 input from the passenger seat is stored in instruction unit 340 described above, removal unit 350 calculates amplitude ratio R and delay time τ between first passenger seat side signal 512 and second passenger seat side signal 522.

[0083] The amplitude ratio R is obtained by dividing the amplitude E of first passenger side signal 512 by the amplitude F of second passenger side signal 522. The amplitudes E and F are each represented by the sum of the amount of displacement from a reference where the intensity is 0 to the maximum intensity in the negative direction and the amount of displacement from a reference where the intensity is 0 to the maximum intensity in the positive direction. The method of obtaining the amplitudes E and F is not limited to this.

[0084] 16 , removal unit 350 shifts second passenger side signal 522 by delay time τ, and further multiplies amplitude F of second passenger side signal 522 by amplitude ratio R. After that, removal unit 350 takes the difference between first passenger side signal 512 and second passenger side signal 522. This enables removal unit 350 to remove first passenger side signal 512 and second passenger side signal 522 from signal 500.

[0085] As shown in Fig. 14, the signal 500 from the passenger seat side is removed and output to the outside. In other words, the signal 500 from the driver's seat side is output to the outside. The signal 500 from the driver's seat side is output to the outside clearly. The output destination may be a voice recognition system.

[0086] The voice recognition system is, for example, a system that allows the driver to operate vehicle accessories by voice 1100. This allows the driver to operate accessories by voice 1100 while holding the steering wheel. Examples of accessories include a navigation system and an air conditioner. The audio device 100 clearly outputs a signal 500 from the driver's seat, so that the voice recognition system can accurately recognize the voice 1100.

[0087] (Fourth embodiment) A more reliable method for estimating the sound source direction is to plot the sound source direction angle θ against a certain time width (T), and if multiple plots are made within a certain angle range, estimate that the sound source 1000 is in that direction, as shown in Fig. 17. This method may be performed by the control unit 300.

[0088] (First Modification) In the acoustic device 100 described thus far, the first microphone 210 and the second microphone 220, each of which has the same directivity as a single unit, are provided on one and the other of the hypotenuse sides of the package 400. And, by providing the first microphone 210 and the second microphone 220 on one and the other of the two hypotenuse sides of the package 400, the first microphone 210 and the second microphone 220 each have different directivities.

[0089] 18, a third microphone 230 may be provided in addition to the first microphone 210 on one of the hypotenuse sides of the package 400. A fourth microphone 240 may be provided in addition to the second microphone 220 on the other part of the hypotenuse side of the control unit 300. The third microphone 230 may be provided on one of the slopes of the package 400 so that the angle between the central plane 11 and the third microphone 230 forms φ3. Similarly, the fourth microphone 240 may be provided on the other of the slopes of the package 400 so that the angle between the central plane 11 and the fourth microphone 240 forms φ4.

[0090] In this case, first microphone 210 and third microphone 230 may have different directivities individually. Second microphone 220 and fourth microphone 240 may have different directivities individually. This makes it possible to estimate the sound source direction by any two of first microphone 210 to fourth microphone 240.

[0091] Furthermore, in this manner, when two or more microphones 200 are provided in a package, the sound source direction may be estimated based on, for example, the first two signals 500 that begin to be input. Note that data corresponding to any two of the first microphone 210 to fourth microphone 240 is stored in storage unit 320.

[0092] Although not shown, three or more microphones 200 may be provided on one of the hypotenuse sides of the package 400. Three or more microphones 200 may be provided on the other hypotenuse side of the package 400.

[0093] (Second Modification) 19, the directivity of first microphone 210 alone and second microphone 220 alone may be different. In that case, package 400 does not have to be approximately triangular prism-shaped. In the second modified example as well, it is possible to estimate the sound source direction by the method described above.

[0094] (Third Modification) 20, the storage unit 320 may have a plurality of first data 610. Specifically, the storage unit 320 may have a plurality of first data 610 depending on the directivities of the first microphone 210 and the second microphone 220. In this case, the estimation unit 330 estimates the sound source direction by reading a corresponding one of the plurality of first data 610. Similarly, the storage unit 320 may have a plurality of second data 620, a plurality of third data 630, and a plurality of fourth data 640 depending on the directivities.

[0095] (Fourth Modification) In the first embodiment, the method of estimating the sound source direction from the amplitude ratio R has been described. However, in the first embodiment, the sound source direction may be estimated from the delay time τ.

[0096] Although the present disclosure has been described based on the embodiment, it is understood that the present disclosure is not limited to the embodiment or structure. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more than one, or less than one element are also within the scope and concept of the present disclosure. [Explanation of symbols]

[0097] Reference Signs List 210...first microphone, 220...second microphone, 230...third microphone, 240...fourth microphone, 310...calculation unit, 320...storage unit, 330...estimation unit, 340...instruction unit, 350...removal unit, 400...package, 500...signal, 610...first data, 620...second data, 630...third data, 640...fourth data, 1000...sound source, 2000...sound source, θ...sound source directional angle, R...amplitude ratio

Claims

1. A plurality of microphones (210, 220, 230, 240) arranged so as to have different directivities from each other; A calculation unit (310) that acquires signals (500) input to two of the plurality of microphones and calculates an amplitude ratio from the amplitudes of the signals; a storage unit (320) storing correspondence information relating to a correspondence between an angle (θ) indicating a direction of a sound source (1000, 2000) relative to the plurality of microphones and the amplitude ratio (R); an estimation unit (330) that estimates the angle from the amplitude ratio based on the correspondence relationship information, The calculation unit calculates a delay time that is a difference between signal acquisition times that occurs based on a difference in distances between the two microphones and the sound source, The storage unit stores first data (610) which is the correspondence information, second data (620) relating to a correspondence between the delay time and the angle, third data (630) representing a transition of a first change amount of the angle per unit amplitude ratio, and fourth data (640) representing a transition of a second change amount of the angle per unit delay time, The acoustic device wherein the estimation unit estimates the angle from the first data or the second data, which corresponds to the smaller amount of change between the first amount of change and the second amount of change.

2. 2. The acoustic device according to claim 1, wherein the plurality of microphones are arranged at a predetermined angle to each other so as to have different directivities from each other.

3. An instruction unit (340) for issuing an instruction to remove the signal in a specific direction in advance; The acoustic device according to claim 1 or 2, further comprising: a removal unit (350) that removes the signal input from the specific direction based on the instruction unit.

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