KR101956784B1 - Acoustic Signal Acquisition Device with Spherical Microphone Array - Google Patents

Abstract

When viewed from a mapping plane in which the spherical body, defined by an θ axis in the equatorial line (defined by θ (= 90 degrees)) direction and a φ axis in the longitude direction, is developed, the φ axis is mapped to an X axis, and the θ axis is mapped to a Y axis, an omnidirectional acoustic signal acquisition device having a structure-improved spherical microphone array and having acoustic sensors (S) disposed on the surface of a spherical body has the acoustic sensors (S) arranged in an amount of 20 to 80. Six to twelve acoustic sensors (S) are arranged in the range of φ (0 to 360 degrees) at the position of an equatorial line (C0) defined by θ (= 90 degrees) to form a horizontal sensor array center line (L0). Two to seven acoustic sensors (S) are arranged in the range of θ (0 to 180 degrees) at the position of one longitude line (C2) defined by φ (= 180 degrees) to form a vertical sensor array center line (C0). The remaining acoustic sensors (S) are arranged to be vertically symmetrical with respect to the horizontal sensor array center line (L0) and laterally symmetrical with respect to the vertical sensor array center line (C0) such that the lines connecting the adjacent acoustic sensors (S) on the spherical body form triangles. Thus, the location of a sound source can be accurately tracked.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an Acoustic Signal Acquisition Device with a Spherical Microphone Array

The present invention relates to an omnidirectional acoustic signal acquisition apparatus, an omnidirectional acoustic visualization apparatus and a sound field reconstruction apparatus using the same.

Acoustic camera is an advanced measuring instrument that visualizes sound and is a new technology equipment needed in various fields such as multimedia information communication equipment, home appliance, automobile, construction. The inventor of the present invention, SM Incorporation Co., Ltd., has secured the world-leading technology in the field of acoustical camera using a microphone and announced that it is the first company to introduce commercial products in Korea.

Microphone Array Beamformer is a method for identifying the location of a noise source. It is a method of visualizing the distribution of a noise source by measuring the sound waves generated in a noise source using a plurality of microphone sensors and performing signal processing thereon. A method for estimating the position of a noise source by reconstructing a signal generated at a specific originating position according to a characteristic of a signal received from each microphone, measuring the magnitude of the sound pressure thereof, and displaying the measured sound pressure level as a spatial distribution.

As shown in FIG. 1, a plurality of MEMS microphones are mounted on a printed circuit board, and the MEMS microphones are mounted on a printed circuit board, Wherein the MEMS microphone has 2 to 10 wings extending in a radial direction.

Patent No. 10-1471299 owned by the present applicant has a front body in which the sound sensing part of the MEMS microphones is disposed facing forward; The MEMS microphones being exposed to the front body (10) in a state where the MEMS microphones are fixed to a substrate (30); A substrate on which the MEMS microphones are mounted; An image capturing unit for exposing a photographing lens through a lens hole of the front body; And a rear body that surrounds the rear side of the substrate and the rear side of the image sensing unit in a state where the substrate is positioned on the rear side of the front body, and the MEMS microphones extend in a straight line, a curved line, or a spiral shape in the radial direction Two to thirty wing portions W are formed and two to fifty MEMS microphones are arranged on one wing portion W apart from each other and fixed to the rim or rear body of the front body 10 And a grip portion protruding rearward.

In the construction of an omnidirectional acoustic signal acquisition device (or a spherical microphone array), the manufacturing cost and the data throughput, which can accurately track the position of a sound source without losing information about the sound source as much as possible with the same number of microphones And to provide a spherical array of sensor arrays capable of performing sound source position tracking and sound field reconstruction most precisely.

The present invention has seen in all directions? By implementing a microarray array that maximizes the symmetry, a minimum number of microphones can be used to reduce the manufacturing cost and data handling, and to track the sound source position and reconstruct the sound field as accurately as possible without losing information about the sound source. In order to provide a spherical sensor array arrangement shape.

The present invention relates to an omnidirectional acoustic camera for measuring and analyzing a sound field generated in an omnidirectional image area and overlaying a visualized sound field in an image image in real time for display on a display device, (A specific sound source) so that only the sound heard in the direction can be reproduced by the user, and the omnidirectional sound signal (hereinafter referred to as " omnidirectional sound signal " And to provide a learning device.

The omnidirectional acoustic signal acquisition apparatus having the structure improved microphone array of spherical arrays of the present invention is an omnidirectional acoustic signal acquisition apparatus in which acoustic sensors (S) are disposed on the surface of a spherical body,

When viewed from the mapping plane in which the spherical body defined by the equatorial line (defined by θ = 90 degrees) and the φ axis defined by the hard axis is extended and the φ axis is defined as the X axis and the θ axis is mapped as the Y axis,

The acoustic sensors S are arranged with 20 to 80 acoustic sensors S;

six to twelve acoustic sensors S are arranged over the range of? = 0 to 360 degrees at the equatorial line C0 defined by? = 90 to form the horizontal sensor array center line L0,

two to seven acoustic sensors S are arranged at a position of one longitude line C2 defined by? = 180 degrees over? = 0 to 180 degrees to form a longitudinal sensor array center line C0,

The remaining acoustic sensors S are disposed symmetrically up and down with respect to the horizontal sensor arrangement center line L0 and symmetrically arranged left and right with respect to the vertical sensor arrangement center line C0,

And the lines connecting adjacent acoustic sensors S on a spherical body are configured to be triangular.

According to the present invention, in constructing an omnidirectional acoustic signal acquisition device (or a spherical microphone array), it is possible to accurately track the position of a sound source and reconstruct a sound field without losing information about the sound source as much as possible with the same number of microphones A spherical array of sensor arrays is provided.

In accordance with the present invention, what would you have seen in all directions? By implementing a microarray array that maximizes the symmetry, a minimum number of microphones can be used to reduce the manufacturing cost and data handling, and to track the sound source position and reconstruct the sound field as accurately as possible without losing information about the sound source. A spherical array of sensor arrays is provided.

According to the present invention, there is provided an omnidirectional acoustic camera for measuring and analyzing a sound field generated in an omnidirectional image area to overlay a visualized sound field in an image image in real time and displaying it on a display device, (Sound source) that can be reproduced only when the user selects one direction (a specific sound source) by reconstructing the generated sound by using a single spherical array and acquiring and reconstructing the sound using a beamformer or a filter. A directional acoustic signal acquisition device is provided.

1 and 2 show a prior art acoustic camera.
Fig. 3 is a sensor array arrangement shape (48, 50) in which acoustic sensors on a spherical body of the present invention are mapped on a mapping plane.
FIG. 4 is a three-dimensional view showing a state in which sensors are arranged on a spherical body on the mapping plane of FIG. 3. FIG.
5 is an omni-directional omnidirectional acoustic visualization apparatus of the present invention.
FIGS. 6A and 6B show an expanded view and a stereoscopic view of a first sensor group A1 arranged at grid points of an octahedron composed of six.
Figs. 7A and 7B show an expanded view and a stereoscopic view of the second sensor group A2 arranged at the hexagonal octahedral lattice point composed of twelve.
FIGS. 7A and 7B show an expanded view and a three-dimensional view of a third sensor group A3 arranged at an octagonal lattice point.
Figs. 8A and 8B show an expanded view and a three-dimensional view of the fourth sensor group A4 arranged at the inflated hexahedron vertex (lattice point) of 24 units.

Hereinafter, an omnidirectional acoustic signal acquisition apparatus, an omnidirectional acoustic visualization apparatus and a sound field reconstruction apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 3 is a sensor array configuration diagram (48, 50) in which the acoustic sensors on the spherical bodies of the present invention are mapped on a mapping plane, and FIG. 4 shows a state in which sensors on the mapping plane of FIG. And FIG. 5 is an omni-directional omnidirectional acoustic visualization apparatus of the present invention. Figs. 6A and 6B show an expanded view and a stereoscopic view of the first sensor group A1 arranged at the lattice points of six octahedrons, Figs. 7A and 7B show the second sensor group A1 arranged at the hexagonal octahedral lattice points composed of twelve FIGS. 7A and 7B show an expanded view and a stereoscopic view of the third sensor group A3 disposed at a hexagonal lattice point composed of eight, and FIGS. 8A and 8B show the expanded and stereoscopic view of an expanded octahedron vertex (Lattice point) of the fourth sensor group (A4).

3 and 4, an omnidirectional acoustic signal acquisition apparatus (or a spherical microphone array) according to an embodiment of the present invention includes an omnidirectional acoustic signal A learning device is a mapping device that expands a spherical body defined by a θ axis in the direction of the equator (θ = 90 degrees) and a φ axis in the direction of the longitude line, maps the φ axis to the X axis, and maps the θ axis to the Y axis In plan view, the acoustic sensors S are arranged with 20 to 80 acoustic sensors S,

Also, the acoustic sensors S are arranged such that six to twelve acoustic sensors S are arranged over the range of? = 0 to 360 degrees at the equatorial line C0 defined by? = 90 degrees, L0). In addition, the acoustic sensors S are arranged such that two to seven acoustic sensors S are arranged at a position of one longitude line C2 defined by? = 180 degrees over? = 0 to 180 degrees (including upper and lower vertexes) Thereby forming the sensor array center line C0.

The remaining acoustic sensors S are arranged symmetrically and vertically symmetrically with respect to the horizontal sensor arrangement center line L0 and symmetrically symmetrically with respect to the vertical sensor arrangement center line C0 (Aligned to abut against each other when the plane is folded with respect to the line). In addition, as shown in FIG. 4, the lines connecting adjacent acoustic sensors S on a spherical body are configured to be triangular.

As shown in FIGS. 3 and 4, the omnidirectional acoustic signal acquisition apparatus (or the rectangular microphone array) according to the embodiment of the present invention includes an upper portion (90 &lt; Fig.) 2-5 column lateral upper sensor array lines (L_ top) are formed and, horizontal orientation sensor array center bottom (0≤θ <90 degrees) upper horizontal orientation sensor array lines on the line (L0) in (L It is preferable that two to five rows of transverse sensor array sub-lines (L_bottom) are formed in a symmetrical shape corresponding to a plurality of transverse direction sensor array tops . In such a configuration, the total number of acoustic sensors is 20 to 80, for example, the number of all the acoustic sensors S arranged in the spherical body is one of 24, 36, 48, and 72 can do. Numerical analysis programs and prototype tests have shown that when the acoustic sensors are not placed at the top and bottom vertices in this figure, it is possible to arrange the sensors as symmetrical as possible in all directions in the spherical array in all directions. In the numerical analysis program and prototype implementation, it was found that a spherical acoustic sensor array having symmetry in all directions and having a maximum equilateral triangle can be achieved with the smallest number of interpolation in the above number.

As shown in FIGS. 3 and 4, the omnidirectional acoustic signal acquisition apparatus (or the rectangular microphone array) according to the embodiment of the present invention includes a left side (0 <? <180 Three to seven columns of longitudinal direction sensor side array lines (C_ one side)

Further, in the right side (180 <? <360 degrees = 0 degree region) of the longitudinal direction sensor array center line C0, a symmetrical shape corresponding to one side array line C_ Sensor side array lines (C_other sides) are formed on the back side of the sensor array on the back side of the sensor array in the shape corresponding to the opposite side (? = 0, 360 degrees) A center line C_B is formed. It is preferable that the number of the acoustic sensors S of the horizontal direction sensor upper array lines L_ upper portions is smaller than or equal to the number of the acoustic sensors S arranged in the horizontal direction sensor arrangement center line C0.

3, an omnidirectional acoustic signal acquisition apparatus (or a spherical microphone array) according to an embodiment of the present invention is characterized in that an acoustic sensor is not disposed at an upper vertex (? = 180 degrees) of a sphere, It is imperative that no acoustic sensors are placed at the lower vertex of the sieve (0 = 0 degrees). The optical pick-up means 20 and 30 are provided in a region covering the upper vertex (? = 180 degrees) of the spherical body as shown here, and spherical bodies are formed in the region covering the lower vertex (? = 0 degree) Means 40 are formed.

<Examples: 48, 50>

3 and 4, an omnidirectional acoustic signal acquisition apparatus (or a spherical microphone array) according to an embodiment of the present invention includes 48 acoustic sensors S arranged in a spherical body .

Some of the 48 acoustic sensors S are connected to the transverse sensor array center line L0 formed by the eight acoustic sensors S arranged equidistantly over the range of? = 0 to 360 degrees at the equatorial line C0 position. Second, third, and fourth horizontal sensor upper array lines (upper portions, L1, L2, L3, L4) formed parallel to the horizontal sensor array center line L0 on the mapping plane ).

Some of the 48 acoustic sensors S are arranged on the mapping plane in the first, second, third and fourth rows of lateral sensor array sub-alignment lines L_ The vertical sensor array center line C0 forming one column at φ = 180 degrees and the rear sensor array center line C0 forming the one column at φ = 180 degrees (φ = 0. 360 degrees) to form a longitudinal sensor array backside-center line C_B which forms one column in parallel.

A part of the 48 acoustic sensors S is divided into first, second, third, fourth, fifth, sixth and seventh columns formed by six columns each between the longitudinal sensor arrangement center line C0 and the longitudinal sensor arrangement rear surface- Second, third, fourth, fifth, sixth, seventh longitudinal sensor side linear array lines (C_ one side, C1, C2, C3, C4, C5, C6, C7) (C_other side, C11, C22, C33, C44, C55, C66, C77) of the fifth, sixth and seventh longitudinal direction sensors are formed.

A sensor array is provided on the longitudinal direction sensor array center line C0 and the longitudinal direction sensor array backside-center line C_B, the fourth longitudinal direction sensor one side array line C4 and the fourth longitudinal direction sensor side array line C44. Are arranged up and down three by three. Two acoustic sensors are disposed on the first, third, fifth, and seventh vertical sensor one-side arrangement lines C1, C3, C5, C7. Five acoustic sensors are arranged on the second and sixth vertical direction sensor side array lines C2 and C6.

Three in the longitudinal direction sensor array center line C0 and the longitudinal direction sensor array backside-center line C_B, one in the fourth longitudinal direction sensor array C4 and one in the fourth longitudinal direction sensor array line C44 The acoustic sensors arranged in the vertical direction are arranged in a horizontal direction parallel to one of the array lines L3, L33 and L0, one by one, due to the same θ (hardness) on the mapping plane. Acoustic sensors arranged two by two on the first, third, fifth and seventh vertical sensor one side array lines C1, C3, C5 and C7 have the same θ (hardness) on the mapping plane, Are arranged laterally in parallel to form L1 and L11.

Acoustic sensors arranged vertically five by five on the second and sixth longitudinal direction sensor side alignment lines C2 and C6 and the second and sixth longitudinal direction sensor side alignment lines C22 and C66 are arranged in the same θ Hardness), so that they are horizontally and parallel to one another to form L4, L2, L0, L22 and L44.

As shown in FIGS. 3 and 4, in the arrangement as described above, it is possible to increase the precision while using more than 45 acoustic sensors without placing the acoustic sensors at the upper and lower vertices, and to reduce the data handling amount with less than 55 acoustic sensors Numerical analysis programs and prototype tests have shown that, in the numerical domain, it is possible to arrange the sensor as symmetrical as possible in all directions (as long as the viewpoint is fixed and the sphere is rotated in various directions) over the spherical array. In the numerical analysis program and prototype implementation, it was found that a spherical acoustic sensor array having the maximum symmetry in all directions and having a maximum equilateral triangle can be achieved with the least amount of interpolation in the above number.

5, the optical photographing means includes an omnidirectional reflecting mirror 20 fixed to the upper portion of the spherical body 10 so as to be spaced apart from the omnidirectional reflecting mirror 20, and an optical image And a photographing lens 30 for photographing the image.

As shown in Figs. 6 (a) and 6 (b), 7 (a) and 7 (b) As shown in FIG. All positions in the rotation group have the same weight. The microphone array of this patent consists of a combination of four unique lattice points having the same weight. A1 (6) + A2 (12) + A3 (FIG. 6), A2 (FIG. 7), A3 8) + A4 (24) 50 lattice points combined in a group of 4 sensors (grid points) are symmetrical in all directions. A total of 48 lattice microphones Array.

As shown in Figs. 6 (a) and 6 (b), 7 (a) and 8 (b) Six first sensor groups A1 arranged at lattice points of the octahedron shown in Fig. 7B (points where at least three lines meet at angles, vertexes), and twelve sensor groups A1 arranged at the octahedron lattice points shown in Fig. 8 sensor group A2, eight third sensor groups A3 arranged at the vertexes of the hexahedron shown in Fig. 8B, and 24 fourth sensor groups A4 arranged at the vertexes of the bull hexahedron shown in Fig. . 50 grid points combined with the four sensor groups (A, A2, A3, A4) are arranged in combination on a single spherical surface so as to be symmetrical when viewed from all directions, It is preferable that the acoustic sensor is removed at the position of the upper vertex where the camera is located and the position of the lower vertex where the pedestal is located to form a total of 48 channel microphone arrays.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but on the contrary, &Lt; RTI ID = 0.0 &gt; and / or &lt; / RTI &gt;

It is to be understood that the appended claims are intended to supplement the understanding of the invention and should not be construed as limiting the scope of the appended claims.

10: spherical body
20: omnidirectional mirror
30: photographing lens
40: spherical shaping means

Claims (11)

delete delete delete delete delete delete An omni-directional acoustic signal acquisition device in which acoustic sensors (S) are disposed on a surface of a spherical body,
When viewed from the mapping plane in which the spherical body defined by the equatorial line (defined by θ = 90 degrees) and the φ axis defined by the hard axis is extended and the φ axis is defined as the X axis and the θ axis is mapped as the Y axis,
The acoustic sensors S are arranged with 20 to 80 acoustic sensors S;
six to twelve acoustic sensors S are arranged over the range of? = 0 to 360 degrees at the equatorial line C0 defined by? = 90 to form the horizontal sensor array center line L0,
two to seven acoustic sensors S are arranged at a position of one longitude line C2 defined by? = 180 degrees over? = 0 to 180 degrees to form a longitudinal sensor array center line C0,
The remaining acoustic sensors S are disposed symmetrically up and down with respect to the horizontal sensor arrangement center line L0 and symmetrically arranged left and right with respect to the vertical sensor arrangement center line C0,
The lines connecting adjacent acoustic sensors S on a spherical body are configured to be triangular,

2 to 5 rows of upper sensor array lines L_in upper portions are formed on the upper portion of the horizontal sensor array center line L0 (90 <?? 180 degrees)
A horizontal sensor array lower line ( 2 to 5 rows ) in a symmetrical shape corresponding to the horizontal sensor upper array lines (upper portions) at a lower portion (0?? <90 degrees) of the horizontal sensor arrangement center line L0 L &lt; / RTI &gt; bottoms)

The acoustic sensor is not disposed at the upper vertex (? = 180 degrees) of the spherical body,
The acoustic sensor is not disposed at the lower vertex (? = 0 degree) of the spherical body,
An optical photographing means is provided in an area covering the upper vertex (? = 180 degrees) of the spherical body,
Spherical shaping means is formed in an area covering the lower vertex (? = 0 degree) of the spherical body,

The 48 acoustic sensors (S) arranged in the spherical body,
The horizontal sensor array center line L0 formed by the eight acoustic sensors S arranged at regular intervals over the range of? = 0 to 360 degrees at the equatorial line C0,
Second, third, and fourth horizontal sensor upper array lines (upper portions, L1, L2, L3, L4) formed parallel to the horizontal sensor array center line L0 on the mapping plane and,
L 1, L 22, L 33, and L 44 of the first, second, third, and fourth columns, which are formed parallel to the horizontal sensor array center line L 0 on the mapping plane, And,
a longitudinal sensor array center line C0 forming one column formed at? = 180 degrees,
A longitudinal sensor array backside-center line C_B, which forms one column parallel to the back surface (φ = 0. 360 degrees) of the longitudinal sensor array center line C0,
Second, third, fourth, fifth, sixth, and seventh columns formed by six columns each between the longitudinal sensor array center line C0 and the longitudinal sensor array backside-center line C_B, 7 vertical direction sensor side array lines (C_ one side, C1, C2, C3, C4, C5, C6, C7), and first, second, third, fourth, fifth, sixth, (C_other side, C11, C22, C33, C44, C55, C66, C77) on the other side of the sensor,
Lt; / RTI &gt;
A sensor array is provided on the longitudinal direction sensor array center line C0 and the longitudinal direction sensor array backside-center line C_B, the fourth longitudinal direction sensor one side array line C4 and the fourth longitudinal direction sensor side array line C44. Are arranged vertically by three,
Two acoustic sensors are arranged on the first, third, fifth, and seventh vertical sensor one side array lines C1, C3, C5, C7,
Characterized in that five acoustic sensors are arranged on the second and sixth longitudinal sensor one side array lines (C2, C6).
8. The method of claim 7,
Three in the longitudinal direction sensor array center line C0 and the longitudinal direction sensor array backside-center line C_B, one in the fourth longitudinal direction sensor array C4 and one in the fourth longitudinal direction sensor array line C44 The acoustic sensors arranged in the vertical direction are arranged in a horizontal direction parallel to one of the array lines L3, L33 and L0, one by one, due to the same θ (hardness) on the mapping plane,

Acoustic sensors arranged two by two on the first, third, fifth, and seventh longitudinal sensor side array lines C1, C3, C5, and C7 have the same θ (hardness) on the mapping plane Wherein the first and second acoustic transducers are positioned horizontally in parallel to form L1 and L11.
8. The method of claim 7,
Acoustic sensors arranged vertically five by five on the second and sixth longitudinal direction sensor side alignment lines C2 and C6 and the second and sixth longitudinal direction sensor side alignment lines C22 and C66 are arranged in the same θ L0, L22, L44 are positioned laterally one after the other in parallel with each other to form L4, L2, L0, L22, L44. The omnidirectional acoustic signal acquisition device with structured microphone array. An omni-directional acoustic signal acquisition device in which acoustic sensors (S) are disposed on a surface of a spherical body,
When viewed from the mapping plane in which the spherical body defined by the equatorial line (defined by θ = 90 degrees) and the φ axis defined by the hard axis is extended and the φ axis is defined as the X axis and the θ axis is mapped as the Y axis,
The acoustic sensors S are arranged with 20 to 80 acoustic sensors S;
six to twelve acoustic sensors S are arranged over the range of? = 0 to 360 degrees at the equatorial line C0 defined by? = 90 to form the horizontal sensor array center line L0,
two to seven acoustic sensors S are arranged at a position of one longitude line C2 defined by? = 180 degrees over? = 0 to 180 degrees to form a longitudinal sensor array center line C0,
The remaining acoustic sensors S are disposed symmetrically up and down with respect to the horizontal sensor arrangement center line L0 and symmetrically arranged left and right with respect to the vertical sensor arrangement center line C0,
The lines connecting adjacent acoustic sensors S on a spherical body are configured to be triangular,

2 to 5 rows of upper sensor array lines L_in upper portions are formed on the upper portion of the horizontal sensor array center line L0 (90 <?? 180 degrees)
A horizontal sensor array lower line ( 2 to 5 rows ) in a symmetrical shape corresponding to the horizontal sensor upper array lines (upper portions) at a lower portion (0?? <90 degrees) of the horizontal sensor arrangement center line L0 L &lt; / RTI &gt; bottoms)

The number of the acoustic sensors S of the transverse sensor upper array lines L_ upper portions is smaller than or equal to the number of the acoustic sensors S arranged in the transverse sensor array center line L0,

The acoustic sensor is not disposed at the upper vertex (? = 180 degrees) of the spherical body,
The acoustic sensor is not disposed at the lower vertex (? = 0 degree) of the spherical body,
An optical photographing means is provided in an area covering the upper vertex (? = 180 degrees) of the spherical body,
Spherical shaping means is formed in an area covering the lower vertex (? = 0 degree) of the spherical body,

The optical pick-
An omnidirectional reflection mirror 20 fixed to an upper portion of the spherical body 10;
A photographic lens 30 which is fixedly exposed on an upper surface of the spherical body 10 and takes an optical image reflected by the reflecting mirror 20;
And a plurality of microphone arrays arranged in the array.
In the omnidirectional acoustic signal acquisition apparatus,
Six first sensor groups A1 arranged at lattice points of the octahedron (points where at least three lines meet at an angle, vertices)
Twelve second sensor groups A2 arranged at six octahedral grid points,
Eight third sensor groups A3 disposed at vertexes of the cube,
Six first sensor groups A1 arranged at the lattice points (at least three points where the at least three lines meet at the angles, the vertexes) of the 24th fourth sensor group (A4) octahedron arranged at the inflated octahedron vertices,
50 grid points combined with the four sensor groups (A, A2, A3, A4) are disposed in combination on a single spherical surface so as to be symmetrical when viewed from all directions,
The acoustic sensor is removed from the lattice points of the first sensor group A1 at an upper vertex position where the optical camera is located and at a lower vertex position where the pedestal is located, and a total of 48 acoustic sensors are provided. (EN) The omnidirectional acoustic signal acquisition device having a structure improved microphone sphere array.

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