WO2022102311A1 - 収音装置 - Google Patents
収音装置 Download PDFInfo
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- WO2022102311A1 WO2022102311A1 PCT/JP2021/037473 JP2021037473W WO2022102311A1 WO 2022102311 A1 WO2022102311 A1 WO 2022102311A1 JP 2021037473 W JP2021037473 W JP 2021037473W WO 2022102311 A1 WO2022102311 A1 WO 2022102311A1
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- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 claims description 26
- 230000005236 sound signal Effects 0.000 claims description 26
- 230000003044 adaptive effect Effects 0.000 claims description 15
- 230000001934 delay Effects 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 description 71
- 238000010586 diagram Methods 0.000 description 51
- 230000002238 attenuated effect Effects 0.000 description 7
- 230000003111 delayed effect Effects 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 230000001629 suppression Effects 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 2
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- 238000003491 array Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
- H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
- H04R1/40—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers
- H04R1/406—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by combining a number of identical transducers microphones
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/08—Mouthpieces; Microphones; Attachments therefor
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
- G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
- G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
- G10L21/0272—Voice signal separating
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/005—Circuits for transducers, loudspeakers or microphones for combining the signals of two or more microphones
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
- H04R2201/40—Details of arrangements for obtaining desired directional characteristic by combining a number of identical transducers covered by H04R1/40 but not provided for in any of its subgroups
- H04R2201/401—2D or 3D arrays of transducers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
- H04R2201/40—Details of arrangements for obtaining desired directional characteristic by combining a number of identical transducers covered by H04R1/40 but not provided for in any of its subgroups
- H04R2201/405—Non-uniform arrays of transducers or a plurality of uniform arrays with different transducer spacing
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2430/00—Signal processing covered by H04R, not provided for in its groups
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2430/00—Signal processing covered by H04R, not provided for in its groups
- H04R2430/03—Synergistic effects of band splitting and sub-band processing
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2430/00—Signal processing covered by H04R, not provided for in its groups
- H04R2430/20—Processing of the output signals of the acoustic transducers of an array for obtaining a desired directivity characteristic
- H04R2430/21—Direction finding using differential microphone array [DMA]
Definitions
- This disclosure relates to a sound collecting device for performing beamforming.
- Non-Patent Document 1 discloses a generalized sidelobes canceller (GSC) as an example of a beam former using an adaptive filter.
- GSC generalized sidelobes canceller
- the present disclosure provides a sound collecting device capable of effectively suppressing sounds other than the target sound.
- the sound collecting device includes a plurality of microphone elements three-dimensionally distributed, and two of a microphone pair composed of any two microphone elements included in the plurality of microphone elements.
- the total number of effective microphone pairs in which the distance between the microphone elements is less than the distance D is larger than the total number of the plurality of microphone elements, and the distance D sets the frequency of the target sound obtained from the plurality of microphone elements to f and the sound velocity.
- D c / 2f
- the straight line connecting the two microphone elements constituting the effective microphone pair is not parallel to any of the straight lines connecting the two microphone elements constituting the other effective microphone pair.
- the sound collecting device can effectively suppress sounds other than the target sound.
- FIG. 1 is an external perspective view of the sound collecting device according to the embodiment.
- FIG. 2 is a block diagram showing a functional configuration of the sound collecting device according to the embodiment.
- FIG. 3 is a diagram schematically showing a calculation formula of an output signal based on the sensitivity characteristics of the main signal, the reference signal, and the output signal.
- FIG. 4 is a diagram showing a three-dimensional arrangement example 1 of a plurality of microphone elements.
- FIG. 5 is a diagram showing an example of planar arrangement of a plurality of microphone elements.
- FIG. 6 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device in which the three-dimensional arrangement example 1 is adopted in the direction along the XZ plane.
- FIG. 1 is an external perspective view of the sound collecting device according to the embodiment.
- FIG. 2 is a block diagram showing a functional configuration of the sound collecting device according to the embodiment.
- FIG. 3 is a diagram schematically showing a calculation formula of an output signal based on the sensitivity characteristics of
- FIG. 7 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device in which the planar arrangement example is adopted in the direction along the XZ plane.
- FIG. 8 is a diagram for explaining a method of calculating the sensitivity characteristics of FIGS. 6 and 7.
- FIG. 9 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XZ plane as the target sound direction, which is generated by the sound collecting device in which the three-dimensional arrangement example 1 is adopted.
- FIG. 10 is a diagram showing a three-dimensional arrangement example 2 of a plurality of microphone elements.
- FIG. 11 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XZ plane as the target sound direction, which is generated by the sound collecting device in which the three-dimensional arrangement example 2 is adopted.
- FIG. 12 is a diagram showing a three-dimensional arrangement example 3 of a plurality of microphone elements.
- FIG. 13 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XZ plane as the target sound direction, which is generated by the sound collecting device in which the three-dimensional arrangement example 3 is adopted.
- FIG. 14 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device in which the three-dimensional arrangement example 1 is adopted in the direction along the XY plane.
- FIG. 15 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device in which the planar arrangement example is adopted in the direction along the XY plane.
- FIG. 16 is a diagram for explaining a method of calculating the sensitivity characteristics of FIGS. 14 and 15.
- FIG. 17 is a diagram showing a three-dimensional arrangement example 4 of a plurality of microphone elements.
- FIG. 18 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device in which the three-dimensional arrangement example 4 is adopted in the direction along the XY plane.
- FIG. 19 is a diagram showing a three-dimensional arrangement example 5 of a plurality of microphone elements.
- FIG. 20 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device in which the three-dimensional arrangement example 5 is adopted in the direction along the XY plane.
- FIG. 21 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XY plane as the target sound direction, which is generated by the sound collecting device in which the plane arrangement example is adopted.
- FIG. 22 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XY plane as the target sound direction, which is generated by the sound collecting device in which the three-dimensional arrangement example 1 is adopted.
- FIG. 23 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XY plane as the target sound direction, which is generated by the sound collecting device in which the three-dimensional arrangement example 4 is adopted.
- FIG. 24 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XY plane as the target sound direction, which is generated by the sound collecting device in which the three-dimensional arrangement example 5 is adopted.
- FIG. 25 is a diagram showing an example in which a plurality of microphone elements are arranged at the positions of the vertices of a quadrangular pyramid.
- FIG. 26 is a diagram showing an example in which a plurality of microphone elements are arranged on the circumference of the bottom surface of the cone and at the apex.
- each figure is a schematic diagram and is not necessarily exactly illustrated. Further, in each figure, the same reference numerals may be given to substantially the same configurations, and duplicate explanations may be omitted or simplified.
- the direction is expressed as the target sound direction
- the sound is expressed as the target sound.
- sounds other than the target sound may be expressed as noise.
- FIG. 1 is an external perspective view of the sound collecting device according to the embodiment.
- FIG. 2 is a block diagram showing a functional configuration of the sound collecting device according to the embodiment.
- the sound collecting device 10 is a substantially disk-shaped device.
- the sound collecting device 10 is installed on a desk, for example, and is used for acquiring voice in a telephone conference or the like.
- the shape of the sound collecting device 10 is not limited to a substantially disk shape.
- the sound collecting device 10 includes a plurality of microphone elements 20a to 20d and a signal processing unit 30 inside the main body as shown in FIG.
- the plurality of microphone elements 20a to 20d constitute a microphone array 20. It is not essential that the sound collecting device 10 includes the signal processing unit 30, and the signal processing unit 30 may be realized as a device different from the sound collecting device 10.
- the plurality of microphone elements 20a to 20d are microphone arrays 20 for generating main signals Xm and reference signals Xr1 to Xr6 used for beamforming.
- the plurality of microphone elements 20a to 20d are used by the signal processing unit 30, which is a beamformer, to acquire an audio signal.
- the plurality of microphone elements 20a to 20d are arranged on the same plane.
- the sound collecting device 10 includes four microphone elements 20a to 20d, but the total number of microphone elements is not particularly limited. The total number of microphone elements may be an even number or an odd number.
- the sound collecting device 10 may include, for example, four or more microphone elements.
- the signal processing unit 30 is a beamformer that performs beamforming using audio signals obtained from each of the plurality of microphone elements 20a to 20d.
- Beamforming of the signal processing unit 30 is signal processing that forms directivity so that noise becomes a blind spot while ensuring sensitivity in the direction of the target sound. That is, according to the beamforming of the signal processing unit 30, noise coming from a direction other than the target sound direction is suppressed.
- Each of the plurality of microphone elements 20a to 20d is an omnidirectional microphone element, but the sound collecting device 10 has high sensitivity in the target sound direction due to the beamforming of the signal processing unit 30.
- the signal processing unit 30 has the same configuration as the generalized sidelobes canceller.
- the signal processing unit 30 is realized by a processor such as a DSP (Digital Signal Processor), for example, but may be realized by a microcomputer or a circuit. Further, the signal processing unit 30 may be realized by a combination of two or more of a processor, a microcomputer, and a circuit.
- the signal processing unit 30 includes delay devices 31a to 31d, a main signal generation unit 31, reference signal generation units 32a to 32f, adaptive filter units 33a to 33f, a subtraction unit 34, and a coefficient updating unit 35.
- the delay devices 31a to 31d have a one-to-one correspondence with the audio signals obtained from each of the plurality of microphone elements 20a to 20d.
- the delay devices 31a to 31d give a delay according to the target sound direction to the audio signals obtained from the plurality of microphone elements 20a to 20d, and output them as output signals.
- the main signal generation unit 31 is an example of the first signal generation unit, and is an audio signal obtained from each of the plurality of microphone elements 20a to 20d, and the delay devices 31a to 31d delay according to the target sound direction.
- the main signal X m is generated by adding the given audio signals.
- the main signal X m is an example of the first signal.
- Each of the reference signal generation units 32a to 32f is an example of the second signal generation unit.
- the reference signal generation units 32a to 32f correspond one-to-one to six sets of microphone pairs composed of any two microphone elements included in the plurality of microphone elements 20a to 20d.
- One reference signal generation unit is an audio signal obtained from each of the microphone elements constituting one set of microphone pairs, and subtracts an audio signal to which a delay corresponding to a target sound direction is given by delayers 31a to 31d. By doing so, a reference signal is generated.
- Each of the reference signals X r1 to X r6 is an example of the second signal.
- the adaptive filter units 33a to 33f correspond to the reference signal generation units 32a to 32f on a one-to-one basis.
- the adaptive filter units 33a to 33f apply the filter coefficients ⁇ 1 to ⁇ 6 to the corresponding reference signal generation units 32a to 32f.
- the reference signal generation unit 32a is a voice signal (output signal of the delayers 31a and 31b) in which the voice signals obtained from the microphone elements 20a and 20b are delayed according to the target sound direction by the delayers 31a and 31b. ) Is subtracted to generate the reference signal X r1 .
- the adaptive filter unit 33a applies the filter coefficient ⁇ 1 to the reference signal X r1 .
- the reference signal generation unit 32b is an audio signal (output of the delay devices 31a and 31c) in which the audio signals obtained from the microphone elements 20a and 20c are delayed according to the target sound direction by the delay devices 31a and 31c, respectively.
- the reference signal Xr2 is generated by subtracting the signal).
- the adaptive filter unit 33b applies the filter coefficient ⁇ 2 to the reference signal X r2 .
- the reference signal generation unit 32c provides an audio signal (output signals of the delayers 31a and 31d) obtained by the delayers 31a and 31d to delay the audio signals obtained from the microphone elements 20a and 20d, respectively, according to the target sound direction.
- the reference signal X r3 is generated by subtraction.
- the adaptive filter unit 33c applies the filter coefficient ⁇ 3 to the reference signal X r3 .
- the reference signal generation unit 32d outputs an audio signal (output signal of the delayers 31b and 31c) to which the audio signals obtained from the microphone elements 20b and 20c are delayed according to the target sound direction by the delayers 31b and 31c.
- the reference signal Xr4 is generated by subtraction.
- the adaptive filter unit 33d applies the filter coefficient ⁇ 4 to the reference signal X r4 .
- the reference signal generation unit 32e outputs an audio signal (output signal of the delayers 31b and 31d) to which the audio signals obtained from the microphone elements 20b and 20d are delayed according to the target sound direction by the delayers 31b and 31d.
- the reference signal X r5 is generated by subtraction.
- the adaptive filter unit 33e applies the filter coefficient ⁇ 5 to the reference signal X r5 .
- the reference signal generation unit 32f outputs an audio signal (output signal of the delay devices 31c and 31d) obtained by giving a delay according to the target sound direction by the delay devices 31c and 31d to the audio signals obtained from the microphone elements 20c and 20d, respectively.
- the reference signal Xr6 is generated by subtraction.
- the adaptive filter unit 33f applies a filter coefficient ⁇ 6 to the reference signal X r6 .
- the subtracting unit 34 subtracts the reference signals X r1 to X r6 to which the filter coefficients ⁇ 1 to ⁇ 6 are applied from the generated main signal X m .
- the output signal Y obtained as a result of the subtraction is expressed by the following equation 1.
- the output signal Y is an example of the third signal.
- the coefficient updating unit 35 updates the filter coefficients ⁇ 1 to ⁇ 6 based on the output signal Y obtained by the subtraction of the subtracting unit.
- FIG. 3 is a diagram schematically showing Equation 1 according to the sensitivity characteristics of the main signal X m , the reference signal X r , and the output signal Y.
- the reference signal X r is the sum of the reference signals X r1 to X r6 to which the filter coefficients ⁇ 1 to ⁇ 6 are applied ( ⁇ 1 X r1 + ⁇ 2 X r2 + ⁇ 3 X r3 + ⁇ 4 X r4 + ⁇ 5 X r5 + ⁇ . It means 6 X r6 ).
- the sensitivity characteristic is, in other words, directivity.
- the main signal X m has high sensitivity in all directions.
- the reference signal Xr has low sensitivity in the target sound direction due to the adaptive filter units 33a to 33f and the coefficient updating unit 35. Therefore, the output signal Y obtained by subtracting the reference signal Xr from the main signal Xm has high sensitivity in the target sound direction.
- the target sound direction is the beam direction.
- the signal processing unit 30 can change the beam direction in the output signal Y.
- the sound collecting device 10 includes a user interface such as a touch panel or an operation button, and the signal processing unit 30 changes the beam direction based on the operation of the user received through the user interface.
- the signal processing unit 30 detects the volume and the like and automatically changes the beam direction.
- the signal processing unit 30 performs beamforming with variable beam direction, it is necessary to reduce the sensitivity of the output signal Y in any direction other than the beam direction as much as possible. .. Therefore, in the sound collecting device 10, the arrangement of a plurality of microphone elements 20a to 20d is defined in order to secure such performance.
- the total number of effective microphone pairs is larger than the total number of the plurality of microphone elements 20a to 20d.
- the effective microphone pair is a microphone pair in which the distance between the two microphone elements is less than the distance D among the microphone pairs composed of any two microphone elements included in the plurality of microphone elements 20a to 20d.
- the total number of effective microphone pairs is 6, and the total number of the plurality of microphone elements is 4.
- the reference signal calculated from the ineffective microphone pair in which the distance between the two microphone elements is equal to or greater than the distance D has the sensitivity assumed from the arrangement of the ineffective microphone pair due to the fact that a folding component is generated in the signal processing. May not have characteristics. That is, the reference signal calculated from the ineffective microphone pair may have an unexpected sensitivity characteristic, which hinders the generation of a highly accurate output signal Y.
- the total number of effective microphone pairs is larger than the total number of the plurality of microphone elements 20a to 20d, so that highly accurate output signal Y can be generated.
- the microphone pairs obtained from the plurality of microphone elements 20a to 20d are all effective microphone pairs. That is, the total number of microphone pairs obtained from the plurality of microphone elements 20a to 20d is equal to the total number of effective microphone pairs. However. A part of the microphone pair obtained from the plurality of microphone elements 20a to 20d may be an effective microphone pair.
- FIG. 4 is a diagram showing a three-dimensional arrangement example 1 of a plurality of microphone elements 20a to 20d.
- the unit of the numerical value described on the X-axis, the Y-axis, and the Z-axis is meters.
- the plurality of microphone elements 20a to 20d are arranged at the positions of the vertices of a regular tetrahedron having a side of about 2.1 cm (0.021 in the coordinates of FIG. 4).
- the length of one side of the regular tetrahedron is 2.1 cm, which is determined by assuming a half wavelength of a frequency of 8 kHz.
- any straight line connecting the two microphone elements constituting the effective microphone pair is not parallel to any of the straight lines connecting the two microphone elements constituting the other effective microphone pair.
- the straight line (line segment) L1 shown by the broken line in FIG. 4 is not parallel to any of the other straight lines L2 to L6.
- FIG. 5 is a diagram showing an example of planar arrangement of a plurality of microphone elements 20a to 20c.
- the unit of the numerical value described on the X-axis, the Y-axis, and the Z-axis is meters.
- the arrangement of the microphone element 20a, the microphone element 20b, and the microphone element 20c is the same as that of the three-dimensional arrangement example 1, but the coordinates of the microphone element 20d are (0, 0, 0).
- the plurality of microphone elements 20a to 20d are arranged on the same plane.
- FIG. 6 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device 10 in which the three-dimensional arrangement example 1 is adopted in the direction along the XZ plane.
- FIG. 7 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device 10 in which the planar arrangement example is adopted in the direction along the XZ plane.
- FIG. 8 is a diagram for explaining a method of calculating the sensitivity characteristics of FIGS. 6 and 7.
- the unit of the numerical value described on the X-axis, the Y-axis, and the Z-axis is meters.
- Each of the six columns in FIGS. 6 and 7 shows the sensitivity characteristics of the reference signal generated using the microphone pair.
- the sensitivity characteristic is, in other words, a directivity pattern.
- the leftmost column of the six columns in FIGS. 6 and 7 corresponds to a reference signal (corresponding to the reference signal Xr3 in FIG. 2) generated by using a microphone pair composed of the microphone element 20d and the microphone element 20a. ) Shows the sensitivity characteristics.
- the second column from the left shows the sensitivity characteristics of the reference signal (corresponding to the reference signal Xr5 in FIG. 2) generated by using the microphone pair composed of the microphone element 20d and the microphone element 20b.
- the third column from the left shows the sensitivity characteristics of the reference signal (corresponding to the reference signal Xr6 in FIG. 2) generated by using the microphone pair composed of the microphone element 20d and the microphone element 20c.
- the fourth column from the left shows the sensitivity characteristics of the reference signal (corresponding to the reference signal Xr1 in FIG. 2) generated by using the microphone pair composed of the microphone element 20a and the microphone element 20b.
- the fifth column from the left shows the sensitivity characteristics of the reference signal (corresponding to the reference signal Xr2 in FIG. 2) generated by using the microphone pair composed of the microphone element 20a and the microphone element 20c.
- the sixth column from the left shows the sensitivity characteristics of the reference signal (corresponding to the reference signal Xr4 in FIG. 2) generated by using the microphone pair composed of the microphone element 20b and the microphone element 20c.
- the three sensitivity characteristics include the sensitivity characteristic of the reference signal having a blind spot in the 90-degree direction, the sensitivity characteristic of the reference signal having a blind spot in the 60-degree direction, and the sensitivity characteristic of the reference signal having a blind spot in the 30-degree direction. ..
- the 90-degree direction means the Z-axis plus direction
- the 60-degree direction is the direction in which the angle is shifted by 30 degrees along the XZ plane from the Z-axis plus direction.
- the 30-degree direction is a direction in which the angle is shifted by 60 degrees along the XZ plane from the Z-axis plus direction.
- the sensitivity characteristics shown in FIGS. 6 and 7 are located at a radius of 1.5 m around the microphone array 20 (aggregate of a plurality of microphone elements 20a to 20d) (FIG. 8). It is a sensitivity characteristic in (shown by a broken line in 8).
- the sensitivity characteristics of the microphone pair including the microphone element 20d are higher in the three-dimensional arrangement example 1 (FIG. 6) than in the plane arrangement example (FIG. 7). It is diverse. That is, if the plurality of microphone elements 20a to 20d are three-dimensionally distributed, the variation in the sensitivity characteristics of the reference signal can be increased as compared with the case where the plurality of microphone elements 20a to 20d are arranged on the same plane. Can be done. The increased variation in sensitivity characteristics is very advantageous for the noise suppression algorithm based on the generalized sidelobes canceller executed by the signal processing unit 30. If the variation in the sensitivity characteristics of the reference signal is increased, the sound collecting device 10 can reduce noise in various directions. That is, the sound collecting device 10 can effectively suppress sounds other than the target sound.
- FIG. 9 is a diagram showing the frequency characteristics of the main signal whose target sound direction is the 90-degree direction along the XZ plane.
- FIG. 9 shows the frequency characteristics in the 90-degree direction, the frequency characteristics in the 30-degree direction, and the frequency characteristics in the 0-degree direction of the main signal whose target sound direction is the 90-degree direction.
- the vertical axis indicates the sound pressure level (SPL: Sound Pressure Level), and the horizontal axis indicates the frequency.
- the sound pressure level is generally flat in the frequency band of 0 to 8 kHz.
- the sound pressure level is attenuated in the high frequency range.
- the sound pressure level is further attenuated in the high frequency range than in the 30 degree direction.
- the sound collecting device 10 in which the three-dimensional arrangement example 1 is adopted can generate a main signal having directivity in the target sound direction (90 degree direction).
- the inventors tried to improve the directivity of the main signal by adjusting the position of the microphone element 20d in the three-dimensional arrangement example 1. Specifically, the inventors calculated the frequency characteristics of the main signals in the three-dimensional arrangement example 2 and the three-dimensional arrangement example 3.
- FIG. 10 is a diagram showing a three-dimensional arrangement example 2 of a plurality of microphone elements 20a to 20d.
- FIG. 11 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XZ plane as the target sound direction, which is generated by the sound collecting device 10 in which the three-dimensional arrangement example 2 is adopted.
- FIG. 11 shows the frequency characteristics in the 90-degree direction, the frequency characteristics in the 30-degree direction, and the frequency characteristics in the 0-degree direction of the main signal whose target sound direction is the 90-degree direction.
- the vertical axis indicates the sound pressure level
- the horizontal axis indicates the frequency.
- the arrangement of the microphone element 20a, the microphone element 20b, and the microphone element 20c is the same as that of the three-dimensional arrangement example 1.
- the microphone element 20d is located on the plus side in the Z-axis direction with respect to the three-dimensional arrangement example 1, and the coordinates of the microphone element 20d are (0, 0, 1.5 ⁇ Z1). That is, in the three-dimensional arrangement example 2, the position (height) of the microphone element 20d with respect to the XY plane is 1.5 times that of the three-dimensional arrangement example 1.
- the distance from the microphone element 20d to each of the microphone elements 20a to 20c is about 2.9 cm (0.029 in the coordinates of FIG. 10).
- the frequency characteristic in the 90-degree direction of the main signal having the 90-degree direction as the target sound direction generated by the sound collecting device 10 in which the three-dimensional arrangement example 2 is adopted is 0 to 8 kHz.
- the sound pressure level is generally flat in the frequency band.
- the frequency characteristic of the main signal in the 30-degree direction when the three-dimensional arrangement example 2 is adopted the sound pressure level is attenuated in the high frequency range, but the frequency at which the sound pressure level begins to be attenuated is the three-dimensional arrangement example 1. Lower than if.
- the sound pressure level is attenuated in the high frequency range, but the frequency at which the sound pressure level begins to be attenuated is the three-dimensional arrangement example 1. Is lower than if was adopted. That is, the sound collecting device 10 in which the three-dimensional arrangement example 2 is adopted can generate a main signal in which the frequency at which the sound pressure level starts to be attenuated is lower than that in the case of the three-dimensional arrangement example 1 in a direction other than the target sound direction. .. That is, the sound collecting device 10 in which the three-dimensional arrangement example 2 is adopted can generate a main signal having a sharper directivity in a high frequency range.
- FIG. 12 is a diagram showing a three-dimensional arrangement example 3 of a plurality of microphone elements 20a to 20d.
- FIG. 13 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XZ plane as the target sound direction, which is generated by the sound collecting device 10 in which the three-dimensional arrangement example 3 is adopted.
- FIG. 13 shows the frequency characteristics in the 90-degree direction, the frequency characteristics in the 30-degree direction, and the frequency characteristics in the 0-degree direction of the main signal whose target sound direction is the 90-degree direction.
- the vertical axis indicates the sound pressure level
- the horizontal axis indicates the frequency.
- the arrangement of the microphone element 20a, the microphone element 20b, and the microphone element 20c is the same as that of the three-dimensional arrangement example 1.
- the microphone element 20d is located on the plus side in the Y-axis direction with respect to the three-dimensional arrangement example 1, and the coordinates of the microphone element 20d are (0, Y1, Z1).
- the distance from the microphone element 20d to the microphone element 20a is about 1.9 cm (0.019 in the coordinates of FIG. 12).
- the distance from the microphone element 20d to each of the microphone element 20b and the microphone element 20c is about 2.3 cm (0.023 in the coordinates of FIG. 12).
- the frequency characteristics of the main signal having the 90-degree direction as the target sound direction generated by the sound collecting device 10 in which the three-dimensional arrangement example 3 is adopted are the 90-degree direction, the 30-degree direction, and the frequency characteristics. It is about the same as the three-dimensional arrangement example 1 in each of the 0 degree directions. That is, the sound collecting device 10 in which the three-dimensional arrangement example 3 is adopted can generate a main signal having directivity in the target sound direction (90 degree direction).
- FIG. 14 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device 10 in which the three-dimensional arrangement example 1 is adopted in the direction along the XY plane.
- FIG. 15 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device 10 in which the planar arrangement example is adopted in the direction along the XY plane.
- FIG. 16 is a diagram for explaining a method of calculating the sensitivity characteristics of FIGS. 14 and 15. In FIG. 16, the unit of the numerical value described on the X-axis, the Y-axis, and the Z-axis is meters.
- the sensitivity characteristics shown in FIGS. 14 and 15 show the sensitivity characteristics of the reference signal in the same format as in FIGS. 6 and 7.
- the 90-degree direction means the Y-axis plus direction
- the 60-degree direction is the direction in which the angle is shifted by 30 degrees along the XY plane from the Y-axis plus direction. Is.
- the 30-degree direction is a direction in which the angle is shifted by 60 degrees along the XY plane from the Y-axis plus direction.
- the sensitivity characteristics shown in FIGS. 14 and 15 are located at a radius of 1.5 m around the microphone array 20 (aggregate of a plurality of microphone elements 20a to 20d) (FIG. 16). 16 is the sensitivity characteristic in (shown by a broken line).
- the sensitivity characteristics of the microphone pair including the microphone element 20d are almost the same in the three-dimensional arrangement example 1 and the two-dimensional arrangement example. That is, even if the plurality of microphone elements 20a to 20d are three-dimensionally distributed, the variation in the sensitivity characteristics of the reference signal is not reduced as compared with the case where the plurality of microphone elements 20a to 20d are arranged on the same plane. It can be said that there is no such thing. That is, it can be said that by sterically distributing and arranging the plurality of microphone elements 20a to 20d, the performance does not deteriorate as compared with the case where the plurality of microphone elements 20a to 20d are arranged on the same plane.
- the inventors confirmed how the sensitivity characteristic of the reference signal changes by adjusting the position of the microphone element 20d in the three-dimensional arrangement example 1. Specifically, the inventors calculated the sensitivity characteristics in the following three-dimensional arrangement example 4 and three-dimensional arrangement example 5.
- FIG. 17 is a diagram showing a three-dimensional arrangement example 4 of a plurality of microphone elements 20a to 20d.
- FIG. 18 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device 10 in which the three-dimensional arrangement example 4 is adopted in the direction along the XY plane.
- the arrangement of the microphone element 20a, the microphone element 20b, and the microphone element 20c is the same as that of the three-dimensional arrangement example 1.
- the microphone element 20d is shifted from the position in the three-dimensional arrangement example 1 in each of the Y-axis direction and the Z-axis direction. When viewed from the Z-axis direction, the position of the microphone element 20d does not overlap with any of the positions of the microphone element 20a, the microphone element 20b, and the microphone element 20c. That is, the microphone element 20d is not located directly above the microphone element 20a, the microphone element 20b, and the microphone element 20c.
- the sensitivity characteristics of the microphone pair including the microphone element 20d are significantly different between the three-dimensional arrangement example 1 and the three-dimensional arrangement example 4. That is, by changing the position of the microphone element 20d, the variation of the sensitivity characteristic of the reference signal can be made different.
- FIG. 19 is a diagram showing a three-dimensional arrangement example 5 of a plurality of microphone elements 20a to 20d.
- FIG. 20 is a diagram showing the sensitivity characteristics of the reference signal generated by the sound collecting device 10 in which the three-dimensional arrangement example 5 is adopted in the direction along the XY plane.
- the arrangement of the microphone element 20a and the microphone element 20d is the same as that of the three-dimensional arrangement example 1.
- the distance between the microphone element 20b and the microphone element 20c is wider than that of the three-dimensional arrangement example 1.
- the microphone element 20b is located on the minus side in the X-axis direction with respect to the three-dimensional arrangement example 1
- the microphone element 20c is located on the plus side in the X-axis direction with respect to the three-dimensional arrangement example 1.
- the positions of the microphone elements 20b and 20c are different between the three-dimensional arrangement example 1 and the three-dimensional arrangement example 5. Therefore, the sensitivity characteristics obtained from the microphone pair in which the microphone element 20a and the microphone element 20d are combined in the leftmost column of FIGS. 14 and 20 are not different between the three-dimensional arrangement example 1 and the three-dimensional arrangement example 5. ..
- the sensitivity characteristics of the microphone pair including the microphone element 20b and the microphone element 20c are different between the three-dimensional arrangement example 1 and the three-dimensional arrangement example 5. That is, by changing the positions of the microphone element 20b and the microphone element 20c, the variation of the sensitivity characteristic of the reference signal can be made different.
- FIG. 21 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XY plane as the target sound direction, which is generated by the sound collecting device 10 in which the plane arrangement example is adopted.
- FIG. 22 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XY plane as the target sound direction, which is generated by the sound collecting device 10 in which the three-dimensional arrangement example 1 is adopted.
- FIG. 23 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XY plane as the target sound direction, which is generated by the sound collecting device 10 in which the three-dimensional arrangement example 4 is adopted.
- FIG. 24 is a diagram showing the frequency characteristics of the main signal having the 90-degree direction along the XY plane as the target sound direction, which is generated by the sound collecting device 10 in which the three-dimensional arrangement example 5 is adopted.
- FIGS. 21 to 24 show the frequency characteristics in the 90-degree direction, the frequency characteristics in the 30-degree direction, and the frequency characteristics in the 0-degree direction of the main signal whose target sound direction is the 90-degree direction.
- the vertical axis indicates the sound pressure level
- the horizontal axis indicates the frequency.
- the frequency characteristics of the main signal when the three-dimensional arrangement example 1 is adopted are in the 90-degree direction, the 30-degree direction, and the 0-degree direction. In each of the above, it can be said that it is about the same as the case where the plane arrangement example is adopted.
- the frequency characteristics of the main signal when the three-dimensional arrangement example 4 is adopted are the three-dimensional arrangement example in the 90-degree direction and the 30-degree direction. It can be said that it is about the same as the case where 1 is adopted.
- the amount of suppression of the sound pressure level in the frequency band of 7 kHz or higher when the three-dimensional arrangement example 4 is adopted is smaller than that when the three-dimensional arrangement example 1 is adopted.
- the frequency characteristic of the main signal when the three-dimensional arrangement example 5 is adopted is that the three-dimensional arrangement example 1 is adopted in the 90-degree direction. It can be said that it is about the same as the case.
- the amount of suppression of the sound pressure level in the frequency band of 4 kHz or higher when the three-dimensional arrangement example 5 is adopted is larger than that when the three-dimensional arrangement example 1 is adopted.
- the amount of suppression of the sound pressure level in the frequency band of 4 kHz to 5 kHz when the three-dimensional arrangement example 5 is adopted is larger than that when the three-dimensional arrangement example 1 is adopted.
- the amount of suppression of the sound pressure level in the frequency band of 7 kHz or higher is smaller than that in the case where the three-dimensional arrangement example 1 is adopted.
- the sound collecting device 10 in which the three-dimensional arrangement example 1, the three-dimensional arrangement example 4, and the three-dimensional arrangement example 5 are adopted can generate a main signal having directivity in the target sound direction (90 degree direction). can.
- the positions of the plurality of microphone elements 20a to 20d correspond to the positions of the vertices of the tetrahedron (triangular pyramid), and a straight line (line) connecting any two microphone elements.
- the six sides of the tetrahedron corresponding to the minute) are not parallel to each other.
- variations in the sensitivity characteristics of the reference signal are increased.
- the plurality of microphone elements 20a to 20d include three microphone elements 20a to 20c located on the same plane and one microphone element 20d not located on the plane. Including, the three microphone elements 20a to 20c are arranged so as to form a triangle in the plane.
- the distance between the two microphone elements constituting the effective microphone pair is different from any of the distances between the two microphone elements constituting the other effective microphone pair. That is, in the three-dimensional arrangement examples 2 to 5, irregular points are provided in the distance between the microphone elements. This makes it possible to sharpen the directivity of the main signal. According to the study by the inventors, by increasing the distance between the microphone elements, the directivity can be sharpened in the region where the frequency of the main signal is low, and by increasing the distance between the microphone elements, the directivity can be sharpened. The directivity can be sharpened in the region where the frequency of the main signal is high.
- the three-dimensional arrangement adopted in the sound collecting device 10 is not limited to the three-dimensional arrangement examples 1 to 5.
- the four or more microphone elements included in the sound collecting device 10 include n (n is a natural number of 3 or more) microphone elements located on the same plane and one or more microphone elements not located on the plane. May include.
- the bottom surface may be arranged at the position of the apex of an n-sided polygonal pyramid.
- the bottom surface may be a regular n-sided polygon (n is an odd number), and the bottom surface may be a polygon whose n sides are not parallel to each other.
- FIG. 25 is a diagram showing an example in which a plurality of microphone elements are arranged at the positions of the vertices of a quadrangular pyramid having a quadrangular bottom surface whose four sides are not parallel to each other. In FIG. 25, the positions of the plurality of microphone elements are indicated by black circles.
- the plurality of microphone elements may be arranged on the circumference of the bottom surface of the cone and at the apex.
- FIG. 26 is a diagram showing an example in which a plurality of microphone elements are arranged on the circumference of the bottom surface of the cone and at the apex. In FIG. 26, the positions of the plurality of microphone elements are indicated by black circles.
- the bottom surface of the cone may be either a perfect circle or an ellipse.
- the plurality of microphone elements may be arranged in a spiral shape. How the plurality of microphone elements are arranged so as to satisfy the condition that the straight line connecting the two microphone elements constituting the effective microphone pair is not parallel to any of the straight lines connecting the two microphone elements constituting the other effective microphone pair. May be done.
- the sound collecting device 10 includes a plurality of microphone elements 20a to 20d three-dimensionally distributed.
- the total number of effective microphone pairs in which the distance between the two microphone elements is less than the distance D is the plurality of microphone elements 20a to 20d. More than the total number of.
- the straight line connecting the two microphone elements constituting the effective microphone pair is not parallel to any of the straight lines connecting the two microphone elements constituting the other effective microphone pair.
- the variation in the sensitivity characteristics of the reference signal is increased, so that the sound collecting device 10 can reduce noise in various directions. That is, the sound collecting device 10 can effectively suppress sounds other than the target sound.
- the plurality of microphone elements 20a to 20d include n microphone elements (n is a natural number of 3 or more) located on the same plane and one or more microphone elements not located on the plane.
- n-sided pyramid n-sided polygonal pyramid
- the n microphone elements are arranged so as to form a regular n-sided polygon on a plane.
- the distance between the two microphone elements constituting the effective microphone pair is different from any of the distances between the two microphone elements constituting the other effective microphone pair.
- the total number of microphone pairs obtained from the plurality of microphone elements 20a to 20d is equal to the total number of effective microphone pairs.
- all the microphone pairs function as effective microphone pairs, so that the sound collecting device 10 can effectively suppress sounds other than the target sound.
- the sound collecting device 10 further adds the delay devices 31a to 31d that give a delay to the audio signals obtained from each of the plurality of microphone elements 20a to 20d, and the output signals of the delay devices 31a to 31d.
- the reference signal Xr1 A filter coefficient is applied from the reference signal generation units 32a to 32f that generate ⁇ X r6 , the adaptive filter units 33a to 33f that apply the filter coefficient to the reference signals X r1 to X r6 , and the generated main signal X m .
- the delay devices 31a to 31d are examples of the delay unit.
- the main signal X m is an example of the first signal, and is an audio signal in which the audio signals obtained from each of the plurality of microphone elements 20a to 20d are delayed according to the target sound direction by the delay devices 31a to 31d ( It is a signal to which the delay devices 31a to 31d output signals) are added.
- the reference signals X r1 to X r6 are examples of the second signal, and the audio signals obtained from each of the two microphone elements constituting the effective microphone pair are delayed according to the target sound direction by the delayers 31a to 31d. It is a signal obtained by subtracting the generated audio signal (output signal of delayers 31a to 31d).
- the main signal generation unit 31 is an example of the first signal generation unit
- each of the reference signal generation units 32a to 32f is an example of the second signal generation unit
- the output signal Y is an example of the third signal. ..
- the sound collecting device 10 can perform beamforming based on the audio signals obtained from the plurality of microphone elements 20a to 20d.
- the shape of the sound collecting device described in the above embodiment is an example, and the sound collecting device may have another shape such as a rectangular parallelepiped shape.
- the configuration of the signal processing unit according to the above embodiment is an example.
- the signal processing unit may include components such as a D / A converter, a low-pass filter (LPF), a high-pass filter (HPF), a power amplifier, or an A / D converter.
- the signal processing executed by the signal processing unit is, for example, digital signal processing, but a part of the signal processing may be analog signal processing.
- the signal processing unit may be realized by being configured with dedicated hardware or by executing a software program suitable for the signal processing unit.
- the signal processing unit may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.
- the signal processing unit may be a circuit (or an integrated circuit). These circuits may form one circuit as a whole, or may be separate circuits from each other. Further, each of these circuits may be a general-purpose circuit or a dedicated circuit.
- the signal processing unit is realized by hardware (circuit), but a part or all of the signal processing unit is realized by executing a software program suitable for the signal processing unit. May be good.
- the signal processing unit may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.
- the sound collecting device of the present disclosure is useful as a sound collecting device used in a telephone conference system or the like.
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Abstract
Description
[収音装置の構成]
以下、実施の形態に係る収音装置の構成について、図1及び図2を用いて説明する。図1は、実施の形態に係る収音装置の外観斜視図である。図2は、実施の形態に係る収音装置の機能構成を示すブロック図である。
収音装置10において、信号処理部30は、出力信号Yにおけるビーム方向を変更することができる。例えば、収音装置10は、タッチパネルまたは操作ボタンなどのユーザインターフェースを備え、信号処理部30は、当該ユーザインターフェースを通じて受け付けたユーザの操作に基づいてビーム方向を変更する。あるいは、信号処理部30は、音量などを検知して自動的にビーム方向を変更する。
図4のように、複数のマイクロホン素子20a~20dが立体的に分散配置されれば、複数のマイクロホン素子20a~20dが同一平面上に配置される場合に比べて、参照信号の感度特性のバリエーションが増加する。以下、このような立体配置例1によって得られる参照信号の感度特性について説明する。まず、立体配置例1の比較対象となる平面配置例について説明する。図5は、複数のマイクロホン素子20a~20cの平面配置例を示す図である。図5において、X軸、Y軸、及び、Z軸に記載された数値の単位は、メートルである。
次に、立体配置例1が採用された収音装置10によって生成される主信号の、XZ平面に沿う方向における周波数特性について説明する。図9は、XZ平面に沿う90度方向を目的音方向とする主信号の周波数特性を示す図である。図9では、90度方向を目的音方向とする主信号の、90度方向の周波数特性、30度方向の周波数特性、及び、0度方向の周波数特性が図示されている。図9では、縦軸は、音圧レベル(SPL:Sound Pressure Level)を示し、横軸は、周波数を示している。
上記図6及び図7では、XZ平面に沿う方向における感度特性について説明したが、以下では、XY平面に沿う方向における感度特性について説明する。図14は、立体配置例1が採用された収音装置10によって生成される参照信号の、XY平面に沿う方向における感度特性を示す図である。図15は、平面配置例が採用された収音装置10によって生成される参照信号の、XY平面に沿う方向における感度特性を示す図である。図16は、図14及び図15の感度特性の計算方法を説明するための図である。図16において、X軸、Y軸、Z軸に記載された数値の単位は、メートルである。
次に、平面配置例、立体配置例1、立体配置例4、及び、立体配置例5が採用された収音装置10によって生成される主信号の、XY平面に沿う方向における周波数特性について説明する。図21は、平面配置例が採用された収音装置10によって生成される、XY平面に沿う90度方向を目的音方向とする主信号の周波数特性を示す図である。図22は、立体配置例1が採用された収音装置10によって生成される、XY平面に沿う90度方向を目的音方向とする主信号の周波数特性を示す図である。図23は、立体配置例4が採用された収音装置10によって生成される、XY平面に沿う90度方向を目的音方向とする主信号の周波数特性を示す図である。図24は、立体配置例5が採用された収音装置10によって生成される、XY平面に沿う90度方向を目的音方向とする主信号の周波数特性を示す図である。
立体配置例1~5においては、有効マイクペアを構成する2つのマイクロホン素子を結ぶ直線は、他の有効マイクペアを構成する2つのマイクロホン素子を結ぶ直線のいずれとも平行でない。ベクトルで表現すると、有効マイクペアを構成する2つのマイクロホン素子を結ぶ直線のベクトルの任意の2つをvi、vj(i、jは自然数)としたときに、vi=t・vj(tは実数)とならない。
ここで、収音装置10に採用される立体配置は、立体配置例1~5に限定されない。例えば、収音装置10が備える4つ以上のマイクロホン素子は、同一の平面に位置するn個(nは3以上の自然数)のマイクロホン素子と、上記平面上に位置しない1個以上のマイクロホン素子とを含んでもよい。例えば、底面がn角形の角錐の頂点の位置に配置されてもよい。
以上説明したように、収音装置10は、立体的に分散配置された複数のマイクロホン素子20a~20dを備える。複数のマイクロホン素子20a~20dに含まれる任意の2つのマイクロホン素子によって構成されるマイクペアのうち、2つのマイクロホン素子間の距離が距離D未満となる有効マイクペアの総数は、複数のマイクロホン素子20a~20dの総数よりも多い。
以上、実施の形態について説明したが、本開示は、このような実施の形態に限定されるものではない。
20 マイクロホンアレイ
20a、20b、20c、20d マイクロホン素子
30 信号処理部
31 主信号生成部
31a、31b、31c、31d 遅延器
32a、32b、32c、32d、32e、32f 参照信号生成部
33a、33b、33c、33d、33e、33f 適応フィルタ部
34 減算部
35 係数更新部
Xm 主信号(第一信号)
Xr 参照信号
Xr1、Xr2、Xr3、Xr4、Xr5、Xr6 参照信号(第二信号)
Y 出力信号(第三信号)
L1~L6 直線
Claims (6)
- 立体的に分散配置された複数のマイクロホン素子を備え、
前記複数のマイクロホン素子に含まれる任意の2つのマイクロホン素子によって構成されるマイクペアのうち、2つのマイクロホン素子間の距離が距離D未満となる有効マイクペアの総数は、前記複数のマイクロホン素子の総数よりも多く、
前記距離Dは、前記複数のマイクロホン素子から得られる目的音の周波数をf、音速をcとすると、D=c/2fで表され、
前記有効マイクペアを構成する2つのマイクロホン素子を結ぶ直線は、他の前記有効マイクペアを構成する2つのマイクロホン素子を結ぶ直線のいずれとも平行でない
収音装置。 - 前記複数のマイクロホン素子は、同一の平面に位置するn個(nは3以上の自然数)のマイクロホン素子と、前記平面に位置しない1個以上のマイクロホン素子とを含む
請求項1に記載の収音装置。 - 前記n個のマイクロホン素子は、前記平面において正n角形を構成するように配置される
請求項2に記載の収音装置。 - 前記有効マイクペアを構成する2つのマイクロホン素子間の距離は、他の前記有効マイクペアを構成する2つのマイクロホン素子間の距離のいずれかと異なる
請求項1~3のいずれか1項に記載の収音装置。 - 前記複数のマイクロホン素子から得られるマイクペアの総数は、前記有効マイクペアの総数に等しい
請求項1~4のいずれか1項に記載の収音装置。 - さらに、
前記複数のマイクロホン素子のそれぞれから得られる音声信号に対して遅延を与える遅延部と、
前記遅延部の出力信号を加算することにより第一信号を生成する第一信号生成部と、
前記遅延部の出力信号のうち、前記有効マイクペアを構成する2つのマイクロホン素子に対応する前記出力信号を減算することにより第二信号を生成する第二信号生成部と、
前記第二信号にフィルタ係数を適用する適応フィルタ部と、
生成された前記第一信号から、前記フィルタ係数が適用された前記第二信号を減算する減算部と、
前記減算部の減算によって得られる第三信号に基づいて前記フィルタ係数を更新する係数更新部とを備える
請求項1~5のいずれか1項に記載の収音装置。
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Citations (4)
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JPH0286397A (ja) * | 1988-09-22 | 1990-03-27 | Nippon Telegr & Teleph Corp <Ntt> | マイクロホンアレー |
JP2019009667A (ja) * | 2017-06-27 | 2019-01-17 | パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカPanasonic Intellectual Property Corporation of America | 集音装置 |
JP2019161400A (ja) * | 2018-03-12 | 2019-09-19 | 沖電気工業株式会社 | 収音装置、プログラム及び方法 |
WO2020166634A1 (ja) * | 2019-02-14 | 2020-08-20 | パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカ | マイクロホン装置 |
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2021
- 2021-10-08 JP JP2022561339A patent/JPWO2022102311A1/ja active Pending
- 2021-10-08 CN CN202180073637.1A patent/CN116472720A/zh active Pending
- 2021-10-08 WO PCT/JP2021/037473 patent/WO2022102311A1/ja active Application Filing
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2023
- 2023-04-21 US US18/137,789 patent/US20230262374A1/en active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH0286397A (ja) * | 1988-09-22 | 1990-03-27 | Nippon Telegr & Teleph Corp <Ntt> | マイクロホンアレー |
JP2019009667A (ja) * | 2017-06-27 | 2019-01-17 | パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカPanasonic Intellectual Property Corporation of America | 集音装置 |
JP2019161400A (ja) * | 2018-03-12 | 2019-09-19 | 沖電気工業株式会社 | 収音装置、プログラム及び方法 |
WO2020166634A1 (ja) * | 2019-02-14 | 2020-08-20 | パナソニック インテレクチュアル プロパティ コーポレーション オブ アメリカ | マイクロホン装置 |
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JPWO2022102311A1 (ja) | 2022-05-19 |
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