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DESCRIPTION JP2007165984

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DESCRIPTION JP2007165984
[PROBLEMS] To provide a sound collection device capable of performing a wider variety of
sound collection. SOLUTION: A plurality of directional microphones 2 whose principal axes can
be independently changed, a signal processing unit 10 which performs audio signal processing
on audio signals input from the microphone 2 based on audio signal processing setting, and a
plurality of them And a setting unit 9 configured to selectively set one of the types of audio
signal processing settings in the signal processing unit 10. By this, it is possible to perform
various sound collection depending on the combination of the orientation of the main axis of the
microphone and the audio signal processing. [Selected figure] Figure 2
Sound pickup device
[0001]
BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a
sound collection device that collects sound with a plurality of microphones.
[0002]
Conventionally, there has been known a sound collection device capable of collecting sound in a
plurality of modes using a plurality of microphones.
For example, Patent Document 1 discloses a sound collection device capable of performing both
stereo sound collection and monaural sound collection with three microphones. In this sound
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pickup apparatus, the three microphones are disposed at the right, the left, and the middle of
them, the right microphone and the left microphone are disposed facing each other, and the
middle microphone is disposed facing the front. The middle microphone only is a unidirectional
microphone that picks up sound specifically from the front.
[0003]
Then, when monaural sound collection is performed, the sound is collected only by the middle
microphone. On the other hand, when performing stereo sound collection, sound is collected only
by the left and right microphones. Thereby, three microphones can be used to perform stereo
sound collection and superdirective monaural sound collection to the front.
[0004]
There is also known a sound pickup device capable of changing the sound pickup angle of a
single microphone. For example, Patent Document 2 describes a sound collection device capable
of collecting sound from various directions by changing the sound collection angle of a single
microphone. Unexamined-Japanese-Patent No. 3-272300 gazette 2004-186774 gazette
[0005]
In the above conventional sound collecting apparatus, it is only possible to select stereo sound
collection or monaural sound collection and to change the pointing direction, and it was not
possible to perform various sound collection.
[0006]
In order to solve the above-mentioned subject, the present invention aims at providing a sound
collection device which can perform more colorful sound collection.
[0007]
In order to solve the above-mentioned subject, the following means are adopted in the present
invention.
[0008]
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(1) The present invention comprises: a plurality of directional microphones capable of changing
the direction of the main axis; a signal processing unit for performing audio signal processing on
audio signals input from the microphones based on audio signal processing settings; And a
setting unit configured to selectively set one of the types of audio signal processing settings in
the signal processing unit.
[0009]
According to the above configuration, the main axes of the plurality of microphones can be
individually changed, and the setting of 1 is selectively set in the signal processing unit by the
mode setting unit among the plurality of types of audio signal processing settings. Ru.
The signal processing unit performs audio signal processing on an audio signal collected by the
microphone.
[0010]
As described above, since it is possible to set the direction of the main axis of the microphone
and the audio signal processing setting independently, it is possible to perform various sound
collection depending on the combination of the direction of the main axis of the microphone and
the audio signal processing. Is possible.
[0011]
(2) According to the present invention, in the above-described sound collection device, the drive
unit changes the direction of the main axis of the plurality of microphones, and the sound
collection direction setting unit sets the direction of the main axis of the plurality of
microphones.
According to this configuration, even if the user does not manually change the main axis of the
microphone, the drive unit can automatically change the main axis of the microphone, thereby
more accurately setting the direction suitable for the user's desired sound collection method.
Becomes possible.
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[0012]
(3) According to the present invention, in the above-described sound collection device, the
operation unit further includes an operation unit that receives from the user a sound collection
mode selection operation from a plurality of types of sound collection modes. The direction of
the main axis of the microphone is changed to the direction corresponding to the sound mode
selection operation, and the setting unit selectively sets one audio signal processing setting
corresponding to the sound collection mode selection operation to the signal processing unit. It is
characterized by
[0013]
According to the above configuration, it is possible to automatically change the main axis of each
microphone in the direction corresponding to the sound collection mode selection operation
from the user.
Further, one audio signal processing setting corresponding to the sound collection mode
selection operation is selectively set in the signal processing unit.
For this reason, it is possible to set the direction of the main axis of each microphone and the
audio signal processing setting to a combination according to the user's desired sound collection
method only by performing the mode selection operation.
[0014]
(4) In the present invention, the sound source tracking mode is included in the plurality of types
of sound collection modes, and when the operation unit selects a sound source tracking mode,
the signal processing unit is configured to The level of the input voice is detected, and the drive
unit changes the orientation of the main axis of each microphone within a predetermined change
area which is different for each microphone so that the detection level in the signal processing
unit becomes maximum. It is characterized in that the direction of the main axis of the
microphone is set.
[0015]
According to the above configuration, when the selection operation of the sound source tracking
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mode is accepted, the signal processing unit detects the level of the sound input to each
microphone.
Then, the drive unit changes the orientation of the main axis of each microphone within a
predetermined change area that is different for each microphone.
Here, in each microphone, the sound collection angle is set so that the detection level by the
signal processing unit becomes maximum, thereby setting the main axes of each microphone to
the sound collection angle of another sound source located in a different direction. It becomes
possible to set.
This makes it possible to collect different sound sources located in different directions with
multiple channels.
[0016]
In addition, when the movement of the sound source is detected due to a change in the detection
level of the signal processing unit or the like, the above process is performed again by the drive
unit, which makes it possible to track the sound source.
[0017]
(5) In the present invention, the sound source separation mode is included in the plurality of
types of sound collection modes, and when the operation unit selects a sound source separation
mode, the signal processing unit receives It is characterized in that a correlation component in
each input audio signal is extracted, and a process of excluding this correlation component from
each audio signal input from each microphone is executed.
[0018]
According to the above configuration, when the selection operation of the sound source
separation mode is accepted with the main axis of each microphone set to a different sound
source direction, the correlation component of each sound signal input from each microphone is
removed from each sound signal. It is eaten.
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Thus, it is possible to remove from the sound signals the sound components that have sneaked in
from the other sound sources of the corresponding sound source, and it is possible to pick up
each sound from each sound source with a high degree of separation.
[0019]
(6) In the present invention, the plurality of types of sound collection modes include a noise
removal mode, and when the operation unit selects a noise removal mode, the signal processing
unit is configured to A feature is characterized in that a correlation component of each input
audio signal is extracted, and a process of excluding this correlation component from an audio
signal from a microphone whose direction of the main axis is set in the sound source direction to
be collected is performed.
[0020]
According to the above configuration, the noise removal mode selection operation is performed
with the direction of the main axis of one microphone set to the direction of the noise source and
the direction of the main axis of the other microphone directed to the direction of the sound
source to be collected. Is accepted, the correlation component of each voice input from each
microphone is removed from the voice from the microphone whose direction of the main axis is
set in the sound source direction to be collected.
This makes it possible to remove noise from the sound from the sound source to be collected and
collect the sound.
[0021]
According to the present invention, the sound collection angle of a plurality of microphones is
changed, and desired sound signal processing selected from among a plurality of types of signal
processing for realizing a plurality of sound collection characteristics is applied to the sound
signal collected by the microphone It is possible to perform a variety of sound pickup depending
on the combination of the orientation of the microphone and the audio signal processing.
As a result, it is possible to provide a sound collection device capable of performing various
sound collection.
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[0022]
The sound collection device 1 which is an embodiment of the present invention will be described
in detail with reference to FIGS. 1 to 5. The main sound collection device 1 can receive one mode
selection from a plurality of types of sound collection modes from the user, and a plurality of
unidirectional microphones (hereinafter referred to as “universal microphones”) at sound
collection angles according to the selected sound collection mode. It is possible to automatically
change the sound collection angle (orientation of the main shaft) of 2) described as
"microphone". At the same time, the sound collection device 1 can perform sound signal
processing according to the sound collection mode out of a plurality of types of sound signal
processing settings on the sound signals collected by the respective microphones 2.
[0023]
FIG. 1 is a perspective view showing the appearance of the sound collection device 1. In the
following description, the front direction of the sound collection device 1 is described as the Y
direction, the back direction as the -Y direction, the right side as the -X direction, and the left side
as the X direction. The audio conference apparatus 1 includes an apparatus main body 1 </ b> A
in the form of a long, substantially rectangular parallelepiped. On the upper surface of the device
main body 1A, the three directional microphones 2 can be rotated 360 degrees in the direction
(left and right direction) shown by the arrow AA in the figure and the direction (height direction)
shown by the arrow BB It is pivotally supported by a support shaft 21 (corresponding to the
drive portion of the present invention) so as to be rotatable 180 degrees. That is, the support
shaft 21 is formed of, for example, a member having at least two axes such as a universal joint,
and the rear end of the microphone 2 is attached to the upper end thereof. By rotating the
support shaft 21, the microphone 2 is rotated as described above.
[0024]
Hereinafter, the microphone 2 arranged on the X side will be referred to as the microphone 2A,
the microphone 2 arranged on the −X side as the microphone 2C, and the microphone 2
arranged in the middle between the microphone 2A and the microphone 2C as the microphone
2B.
[0025]
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As a result, it is possible to change the sound collection angles of the respective microphones 2
and sound of various directions can be collected.
[0026]
The external interface 3 is disposed on the X side on the Y side of the sound collection device 1,
and the operation unit 4 and the display unit 5 are disposed on the −X side.
The external interface 3 includes a plurality of connection terminals for connecting to an external
audio device (for example, a speaker device), which makes it possible to output the collected
audio signal to the external audio device.
In addition, the operation unit 4 includes a plurality of operation buttons 41, and each operation
button 41 is pressed by a user with a finger or the like to receive various operations. This
operation includes, for example, an operation of selecting one of a plurality of types of sound
collection modes. The sound collection angle of each microphone 2 and the sound signal
processing when the sound collection mode and each sound collection mode are selected will be
described in detail later.
[0027]
The display unit 5 is for displaying the set mode and the waveform of the input voice, and is
realized by, for example, an LCD (Liquid Crystal Display) or the like. A touch panel may be
disposed on the surface of the LCD to integrally configure the operation unit 4 and the display
unit 5.
[0028]
FIG. 2 is a block diagram showing the configuration of the sound collection device 1 shown in
FIG. The sound collection device 1 includes a drive unit 22, a position sensor 23, an A / D (analog
/ digital) converter 6, and a microphone angle control unit in addition to the microphone 2, the
external interface 3, the operation unit 4, and the display unit 5 described above. 7, a storage
unit 8, a mode setting unit 9, a signal processing unit 10, a D / A (digital / analog) converter 11,
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and a display control unit 12. The drive unit 22 and the position sensor 23 are attached to the
support shaft 21 shown in FIG.
[0029]
The driving units 22 and the position sensors 23 are disposed in the number corresponding to
the microphones 2A to 2C. The drive unit 22 and the position sensor 23 corresponding to each
of the microphones 2A to 2C are suffixed with the same alphabet as the corresponding
microphone 2 and are described as drive units 22A to 22C and position sensors 23A to 23C.
[0030]
The drive unit 22 is configured to be able to rotate the support shaft 21 as described above and
to rotate the microphone 2 in the directions A-A and B-B shown in FIG. 1. The drive unit 22
drives the support shaft 21 in accordance with a drive command from the microphone angle
control unit 7. Each of the microphones 2 can not only be automatically rotated by the drive unit
22, but also can be manually rotated by the user moving the support shaft 21 manually.
[0031]
As a result, the user can turn the microphone toward the sound source, and manually adjust the
sound collection angle set automatically.
[0032]
The position sensor 23 detects the angle of each microphone 2 and inputs a signal indicating the
detected angle (microphone angle) to the microphone angle control unit 7.
The A / D converter 6 converts an analog audio signal input from each microphone 2 into a
digital audio signal and inputs the digital audio signal to the signal processing unit 10.
[0033]
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The microphone angle control unit 7 corresponds to the sound collection direction setting unit of
the present invention, and is realized by, for example, a CPU (Central Processing Unit), etc. A
signal indicating an angle is input from the position sensor 23, and each microphone is input. Get
2 angles. The microphone angle control unit 7 inputs a change instruction (a sound collection
angle change instruction) of the sound collection angle of each microphone 2 from the mode
setting unit 9 or the sound source tracking unit 102 (see FIG. 3) described later. The microphone
angle control unit 7 calculates the difference between the sound collection angle indicated by the
sound collection angle change instruction and the actual angle of each microphone 2 and outputs
a drive command for driving the support shaft 21 to the drive unit 22 by this difference. Thus,
the sound collection angle is set in the drive unit 22. As a result, each microphone 2 is rotated at
an angle corresponding to the mode setting.
[0034]
The storage unit 8 is realized by, for example, a non-volatile semiconductor memory, a hard disk
or the like, and stores various programs for executing various audio signal processing modes.
The various programs include a stereo 1 program, a stereo 2 program, a multi-channel sound
collecting program, a sound source separation program, a noise removal program, a sound
source tracking program, a super-oriented program, and the like.
[0035]
In the stereo 1 program and stereo 2 program, the microphone 2A is directed to the X side, the
microphone 2C is directed to the -X side, and the microphone 2B is directed to the front, and the
microphones 2A to 2C set to such angles are stereo It is a program to make it pick up sound.
Note that the reason why the microphone 2B is directed in the front direction is to prevent the
loss of sound from the front.
[0036]
The difference between the stereo 1 program and the stereo 2 program is that the stereo 2
program sets the opening angle between the microphone 2A and the microphone 2C wider than
the stereo 1 program. This enables stereo sound collection at various opening angles. The stereo
1 program is read out by the mode setting unit 9 when the selection operation of the stereo 1
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mode is accepted by the operation unit 4.
[0037]
The multi-channel sound collection program is a program for setting the microphones 2A to 2C
to different angles and collecting sound from sound sources at different angles with multichannel. The multi-channel sound collection program is read out by the mode setting unit 9 when
the selection operation of the multi-channel sound collection mode or the sound source tracking
multi-channel sound collection mode is accepted. The multi-channel sound collection mode or the
sound source tracking multi-channel sound collection mode will be described in detail later.
[0038]
The sound source separation program sets any two of the microphones 2A to 2C to different
angles, and picks up voices from sound sources at different angles with multi-channel in a state
where the degree of separation of each voice is high. Is a program for The sound source
separation program is read out by the mode setting unit 9 when the selection operation of the
sound source separation mode or the sound source tracking sound source separation mode is
accepted. The sound source separation mode or the sound source tracking and sound source
separation mode will be described later in detail.
[0039]
The noise removal program sets an angle of one of two of the microphones 2A to 2C to the
sound source direction of the noise, sets another angle to the sound source direction of the sound
collection target, and noise from the sound collection target voice Is a program for performing
audio signal processing to remove The noise removal program is read out by the mode setting
unit 9 when the selection operation of the noise removal mode or the sound source tracking
noise removal mode is accepted. Details of the noise removal mode or the sound source tracking
noise removal mode will be described later.
[0040]
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The sound source tracking program is a program for tracking the angle of the microphone 2
corresponding to the sound source in the direction of the sound source to be collected. The
sound source tracking program is read out by the mode setting unit 9 together with the multichannel sound collection program when the selection operation of the sound source tracking
multi-channel sound collection mode is accepted. The sound source tracking program is read by
the mode setting unit 9 together with the sound source separation program when the selection
operation of the sound source tracking sound source separation mode is accepted. The sound
source tracking noise removal program is read out by the mode setting unit 9 together with the
noise removal program when the selection operation of the sound source tracking noise removal
mode is accepted.
[0041]
The super-orientation program is a program for picking up sound to be picked up with
superdirectivity by setting all the angles of the microphones 2A to 2C to the sound source
direction to be picked up. The super-oriented program is read by the mode setting unit 9 when
the selection operation of the super-oriented mode is accepted.
[0042]
Further, the storage unit 8 stores the initial angle of each microphone 2 corresponding to the
mode selection in association with each mode selection.
[0043]
The mode setting unit 9 constitutes a drive unit of the present invention together with the drive
unit 22, receives an operation signal indicating a mode selection operation from the operation
unit 4, and acquires the mode selection operation by the input of this signal.
The mode setting unit 9 reads the initial angle of each microphone 2 corresponding to the mode
selection operation from the storage unit 8, and the microphone angle control unit 7 instructs
the sound collection angle change instruction to change the sound collection angle to this initial
angle. Enter in As a result, when switching the audio signal processing mode, it is possible to set
the angle of the microphone 2 to a predetermined initial angle.
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[0044]
In addition, the mode setting unit 9 reads one or a plurality of programs corresponding to the
mode selection operation acquired as described above from the storage unit 8, and changes the
setting of the signal processing unit 10 based on the read program. As a result, audio signal
processing according to the mode selection operation can be performed by the signal processing
unit 10, and at the same time, the sound collection angle of each microphone 2 can be
independently set to a predetermined value, realizing versatile sound collection. It will be
possible to
[0045]
The signal processing unit 10 is realized by, for example, a DSP, and performs audio signal
processing on each audio signal input from each microphone 2 through the A / D converter 6.
The signal processing unit 10 changes the setting of the audio signal processing by the mode
setting unit 9 and performs different audio signal processing according to the setting. The signal
processing unit 10 inputs the audio signal after audio signal processing to the external interface
3 via the D / A converter 11 and not via the D / A converter 11. This enables digital audio signals
and analog audio signals to be input to an external audio device.
[0046]
The display control unit 12 controls the display of the display unit 5 to display the waveform of
the input sound, the mode setting, and the like.
[0047]
FIG. 3A is a block diagram showing a functional configuration of the signal processing unit 10
when the multi-channel sound collection mode is set.
The signal processing unit 10 includes three amplifiers 101 corresponding to the microphones
2A to 2C. In order to distinguish the amplifiers 101 corresponding to the respective microphones
2A to 2C, the same alphabet as the corresponding microphone 2 is added as a suffix and
described as the amplifiers 101A to 101C.
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[0048]
The amplifiers 101A to 101C receive audio signals from the corresponding microphones 2A to
2C via the A / D converter 6. The amplifiers 101 </ b> A to 101 </ b> C amplify the level of the
input audio signal and input the amplified signal to the external interface 3. Here, in the
amplifiers 101A to 101C, level control parameters for controlling the level are set from the mode
setting unit 9, and level amplification is performed based on the level control parameters. In the
multi-channel mode, it is preferable that the same level control value be set so that the level
amplification degree of each amplifier 101 becomes the same.
[0049]
As described above, by setting the signal processing unit 10 and setting the microphones 2 to
different microphone angles, it is possible to collect voices from the respective sound sources
positioned in the respective microphone angle directions with multi-channels. .
[0050]
In addition, when the sound source tracking multi-channel sound collection mode is set, the
signal processing unit 10 includes the sound source tracking unit 102 at the subsequent stage of
the amplifier 101, as indicated by a broken line in FIG.
The sound source tracking unit 102 executes a sound source tracking process described later. In
the sound source tracking process, the sound source tracking unit 102 detects the movement of
the sound source position from the level of the input audio signal, searches the sound source
position in a predetermined search range, acquires the sound source direction, and acquires the
acquired sound source direction A microphone angle control instruction to change the
microphone angle is input to the microphone angle control unit 7. By this, even when the sound
source moves like a person who talks while walking, the sound source can be tracked and voice
can be input.
[0051]
FIG. 3B is a block diagram showing a functional configuration of the signal processing unit 10
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when the sound source separation mode is set. The signal processing unit 10 includes two
amplifiers 101, a correlation extraction unit 103, and two addition units 104. In the sound
source separation mode, two microphones 2 among the microphones 2A to 2C are used. The
microphone angles of the two microphones 2 are manually or automatically set to different
sound source directions, and voices from different sound sources p1 and p2 are input.
[0052]
The voice A generated by the sound source p1 located at the microphone angle of the
microphone 2 is input to the microphone 2 of 1, and the voice B generated by the sound source
p2 located at the microphone angle of the microphone 2 is input to the other microphones 2
Mainly input. Along with this, not only the voice A but also the voice looped in from the sound
source p2 (a voice having the same content as the voice B, but described as “voice b” to
distinguish it as a wraparound voice) is input to the microphone 2 of 1 Therefore, A + b voice is
input. Further, not only the voice B but also the voice a (a voice having the same content as the
voice A but described as “voice a” to be distinguished as a wraparound voice) are input to the
other microphone 2 as well. Therefore, B + a voice is input.
[0053]
Since both a voice and b voice are input from a position deviated from the main axis of the
directional microphone, their levels are smaller than that of voice A and voice B which are the
original voice inputs.
[0054]
The two amplifiers 101 (1011 and 1012) correspond to the microphones 2 used.
The amplifier 1011 receives an A + b audio signal, and the amplifier 1012 receives a B + a audio
signal. The amplifiers 1011 and 1012 perform level amplification of each signal based on the set
level control parameter. The A + b audio signal after level amplification and the B + a audio signal
are input to the correlation extraction unit 103.
[0055]
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The correlation extraction unit 103 extracts the correlation between the input A + b audio signal
and the B + a audio signal. That is, the correlation part is an a + b speech signal. The a + b audio
signal is inverted in phase and input to each of the adders 104 (1041 and 1042).
[0056]
The signal path from the amplifier 1011 to the correlation extraction unit 103 is branched to the
addition unit 104 (1041), and the A + b audio signal is input to the addition unit 1041. The
signal path from the amplifier 1012 to the correlation extraction unit 103 is branched to the
addition unit 104 (1042), and the B + a audio signal is input to the addition unit 1042.
[0057]
The addition unit 1041 adds the input A + b audio signal and the input a + b audio signal whose
phase is inverted. By this, the A-a speech signal becomes a residual signal, and it becomes
possible to remove the component of the speech b and separate only the component of the
speech A. The addition unit 1041 adds the input B + a audio signal and the input a + b audio
signal whose phase is inverted. As a result, the B-b speech signal becomes a residual signal, and it
becomes possible to remove the component of the speech a and separate only the component of
the speech B.
[0058]
The residual signal (B-b speech signal, A-a speech signal) is input from the adding units 1041 and
1042 to the external interface 3.
[0059]
As described above, in the sound source separation mode, the sound from each of the sound
sources p1 and p2 can be separated and collected.
[0060]
Further, when the sound source tracking sound separation mode is set, two sound source
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tracking units 102 (1021 and 1022) shown by broken lines in the figure are provided in the
middle of each signal path from the amplifier 101 to the correlation extraction unit 103. .
Each sound source tracking unit 102 tracks the direction of the sound source after movement
when the sound sources p1 and p2 move as described above, and changes the microphone angle
of the corresponding microphone 2 to a microphone angle control instruction to change the
microphone angle control unit Enter 7
As a result, in the sound source tracking sound separation mode, the sound sources of the sound
sources p1 and p2 can be separated and acquired while tracking the directions of the sound
sources p1 and p2.
[0061]
FIG. 3C is a block diagram showing a functional configuration of the signal processing unit 10
when the noise removal mode is set. In the noise removal mode, only the voice from the sound
source p1 is the sound collection target, and the sound from the sound source p2 is removed as
noise from the voice to be collected and collected. That is, only the voice A is a sound collection
target, and the voice b is noise. Therefore, in this mode, the signal processing unit 10 is provided
with only one addition unit 104 (addition unit 1041), and only the A-a audio signal calculated by
the addition unit 1041 is input to the external interface 3 Is different from the sound source
separation mode.
[0062]
As a result, in the noise removal mode, it is possible to remove only the component of the voice A
to be collected by removing the component of the voice B which is noise from the input voice
signal.
[0063]
When the sound source tracking noise removal mode is set, the signal processing unit 10 further
includes two sound source tracking units 102 (1021 and 1022) indicated by broken lines in FIG.
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The positions and functions of the sound source tracking units 1021 and 1022 are the same as
in the sound source tracking and sound source separation mode. As a result, even when the
sound source p1 and the sound source p2 move, noise can be removed to separate and collect
the voice A as the sound collection target.
[0064]
FIG. 4 is a flowchart showing the mode setting process performed by the mode setting unit 9.
This process is started when an operation signal is input to the mode setting unit 9. First, the
mode setting unit 9 detects a sound collection mode indicated by the input operation signal (S1).
The mode setting unit 9 reads a program corresponding to the detected sound collection mode
from the storage unit 8 (S2).
[0065]
The mode setting unit 9 inputs a setting change instruction signal to the signal processing unit
10 based on the read program (S3). For example, the setting change includes changing a level
control parameter for controlling the level of the audio signal, changing a functional
configuration of the signal processing unit 10, and the like (see FIGS. 3A to 3C). The signal
processing unit 10 to which the instruction signal is input performs setting change processing
according to the instruction, and then inputs a completion signal indicating the completion of
this processing to the mode setting unit 9.
[0066]
Thereafter, the mode setting unit 9 determines whether the completion signal is input within a
predetermined time (S4), and when it is determined that the completion signal is input within the
predetermined time (YES in S4), this process is performed. End the On the other hand, when it is
determined that the completion signal has not been input within the predetermined time (NO in
S4), mode setting unit 9 causes display control unit 12 to display an error (S5), and thereafter
this process is performed. End.
[0067]
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FIG. 5 is a flowchart showing the sound source tracking process performed by the sound source
tracking unit 102 shown in FIG. First, the sound source tracking unit 102 detects the volume
level of the input voice at predetermined time intervals, and starts processing for storing the
latest predetermined number of detection levels in the storage unit 8 (S11). The sound source
tracking unit 102 repeatedly determines whether or not the detection levels for the past several
times have dropped continuously by a predetermined level or more until it is determined that the
detection levels have dropped (S12).
[0068]
If it is determined that the detection levels of the past several times have continuously dropped
by a predetermined level or more (YES in S12), the sound source tracking unit 102 determines
the microphone 2 angle within a predetermined search range with respect to the microphone
angle control unit 7 The sound collection angle change instruction of the change of is output
(S13). Here, the change range of the microphone angle for each microphone 2 is initially set in
different ranges, but the change range can be changed by the user's operation using the
operation unit 4. The sound source tracking units 102A to 102C output a sound collection angle
change instruction to change the microphone angle within the change range of the microphone
angle set for the corresponding microphone 2.
[0069]
The sound source tracking unit 102 determines whether the level of the input voice is larger
than the past maximum level after the microphone angle change (S14). Here, immediately after
the microphone angle change start, the initial value of the past maximum level is set to 0.
[0070]
If it is determined that the level of the input voice is equal to or less than the past maximum level
(NO in S14), the sound source tracking unit 102 executes step S16 described later. On the other
hand, when it is determined that the level of the input voice is higher than the past maximum
level (YES in S14), the sound source tracking unit 102 updates the past maximum level with the
detection level (S15). The sound source tracking unit 102 stores the microphone angle at this
time as the highest microphone angle in the past. Here, when the highest microphone angle in
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the past has already been stored, the sound source tracking unit 102 updates the highest
microphone angle in the past with the microphone angle corresponding to the highest level in
the past.
[0071]
Since the initial value of the past maximum level is 0 immediately after the start of the
microphone angle change, the sound source tracking unit 102 stores the first detected level as
the past maximum level, and the microphone angle at this time is the highest microphone angle
in the past. Remember as. After the second time, the sound source tracking unit 102 compares
the stored maximum level with the detection level.
[0072]
Thereafter, the sound source tracking unit 102 determines whether or not the sound collection
angle change instruction of the change of the microphone angle is output in all the search ranges
(S16). If it is not determined that the sound collection angle change instruction for changing the
microphone angle is output in all search ranges (NO in S16), the sound source tracking unit 102
returns the process to step S13 and has not changed it yet Outputs a sound collection angle
change instruction to the microphone angle.
[0073]
On the other hand, when it is determined that the sound collection angle change instruction of
the change of the microphone angle is output in all the search ranges (YES in S16), the sound
source tracking unit 102 sets the microphone angle of the corresponding microphone 2 to the
highest microphone angle of the past. The voice collection angle change instruction to be
changed to is output to the microphone angle control unit 7 (S17). As a result, it is possible to
change the sound collection angle in the direction of the largest sound level and to track the
moving sound source. Thereafter, the sound source tracking unit 102 returns the process to step
S12.
[0074]
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According to the above configuration, in the present embodiment, according to the sound
collection mode, one audio signal processing setting is selectively set in the signal processing
unit 10 from among a plurality of types of audio signal processing, and the orientation of each
microphone 2 Are also set independently. As a result, various audio signal processing can be
performed depending on the sound collection mode, and therefore, various sound collection can
be performed.
[0075]
The following modifications can be employed in the present embodiment.
[0076]
(1) Although the number of microphones 2 is three in the present embodiment, the number of
microphones 2 is not limited to three, as long as two or more microphones 2 are provided.
[0077]
(2) Further, the rotatable range of the microphone 2 is not limited to 360 degrees in the A-A
direction and 180 degrees in the B-B direction, as long as the microphone angle can be changed.
[0078]
(3) The collection angle and the content of audio signal processing corresponding to a plurality
of types of sound collection modes and sound collection modes are not limited to the above, and
the sound collection angles and signal processing settings corresponding to the selected sound
collection mode are Any configuration may be used as long as it is selectively set one of a
plurality of types.
Further, the present invention is not limited to the configuration in which the sound collection
angle and the sound signal processing setting are changed by selecting the sound collection
mode, and one sound signal processing setting is selectively selected from plural kinds of sound
signal processing settings by another method. The configuration may be set to
For example, the configuration may be such that an audio signal processing setting
corresponding to the microphone angle is selectively made by detecting the microphone angle
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changed manually or automatically.
[0079]
It is a perspective view which shows the external appearance of a sound collection apparatus.
It is a block diagram which shows the structure of the sound collection apparatus shown in FIG.
FIG. 6A is a block diagram showing a functional configuration of a signal processing unit when a
multi-channel sound collection mode is set. (B) is a block diagram showing a functional
configuration of the signal processing unit when the sound source separation mode is set. (C) is a
block diagram showing a functional configuration of the signal processing unit when the noise
removal mode is set. It is a flowchart which shows the mode setting process which a mode
setting part performs. It is a flowchart which shows the sound source tracking process which the
sound source tracking part shown in FIG. 3 performs.
Explanation of sign
[0080]
1-sound collection device 2 (2A-2C)-microphone 4-operation unit 7-microphone angle control
unit (drive unit) 9-mode setting unit (setting unit) 10-signal processing unit 21-support shaft
(drive unit) 22 (22A to 22C)-drive unit
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