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JPH1118198

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DESCRIPTION JPH1118198
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
sound collecting apparatus for collecting signals by processing an output signal of a microphone
array composed of a plurality of microphones and to apply the sound collecting apparatus to a
communication conference such as a video conference. The present invention relates to a method
and a device for detecting a target sound source area in a communication conference apparatus,
and in particular, microphones in an area where a target sound source is present under an
environment in which unnecessary sound and receiving speech from a receiving speaker in a
communication conference apparatus are intermittently generated. BACKGROUND OF THE
INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus
for detecting a target sound source area for enabling the directivity of an array to be picked up.
[0002]
2. Description of the Related Art In recent years, with the advancement of multimedia technology,
communication conferences such as video conferences in the form of loud-speaking speech using
microphones and speakers are becoming possible. In such a case, a sound collecting device
capable of natural conversation without being aware of microphones and collecting only target
sound such as voice is required without installing microphones for the number of speakers on
the desk of the communication conference. There is.
[0003]
03-05-2019
1
As an example of such a sound collection device, there is a sound collection device that installs a
plurality of microphones (microphone arrays) and processes the outputs of the microphones to
extract a target sound. There are many known signal processing methods for suppressing noise
and extracting a target sound using such a microphone array, such as the delay-sum method,
AMNOR, etc. (For example, Oga, Yamazaki, and Kanada "Acoustic Systems and Digital
Processing") , The Institute of Electronics, Information and Communication Engineers, 1995, pp.
173-197) For example, in the delay-sum method, the target sound is extracted as follows.
[0004]
FIG. 7 is a diagram for explaining the principle of target sound extraction by the delay-and-sum
method. In FIG. 7, 1 is a sound pickup unit (microphone array) 21, 22,..., 2M is a microphone (M
is the number of microphones), 31, 32,. , 5 is an output signal, 6 is a noise suppression unit, d is
a microphone interval, s (t) is a sound wave (t represents time) arriving at the sound collection
unit 1, and θ is a sound collection unit 1 of the sound wave s (t) Is the time difference (delay
time) for the sound wave to reach each microphone.
[0005]
It is assumed that the microphones 21, 22,..., 2M in FIG. 1 are linearly arranged at equal intervals
d, and the sound waves s (t) reach the microphones linearly arranged from the distance at an
angle θ. At this time, the distance that the sound wave that has reached the microphone 21
propagates until it reaches the microphone 22 is represented by dsinθ from the microphone
distance d and the arrival angle θ. Similarly, the distance propagated to the i-th microphone 2i (i
= 2,..., M) is represented by (i-1) d sin θ. Therefore, the delay time τi until reaching the
microphone 2i (i = 2,..., M) can be expressed by the following equation (1) by dividing this
propagation distance by the speed of sound c based on the microphone 21 Be
[0006]
Here, when the output signal from each microphone 2i (i = 1,..., M) is represented by xi (t), since
the sound wave s (t) is delayed by τi, the following equation ( It becomes like 2).
[0007]
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2
Here, it will be shown that if the delay amount Di of the delay device 3i (i = 1, 2,..., M) is
appropriately set, only the sound wave arriving from the θ direction can be emphasized and
output to the output signal 5.
[0008]
The delay amount Di of the delay device 3i (i = 1, 2,..., M) is set as in the following equation (3).
[0009]
D0 is a fixed delay amount to be added to prevent the accuracy in realizing the delay
characteristic with a digital filter when the value of .tau.i is too small.
[0010]
At this time, the output of the delay device 3i (i = 1, 2,..., M) is the signal of the equation (2) in
which the delay Di of the equation (3) is generated. become.
[0011]
That is, regardless of the microphone number i, s (t) becomes the same signal delayed by D0.
[0012]
When the signals are thus added by the adder 4 after the phases are aligned, the sound waves
coming from the θ direction are emphasized by the amount of the addition.
On the other hand, since the sound waves coming from the θN direction different from the θ
direction are received with a delay time τN different from τi, the delay amount of equation (3)
does not match the phase, and the adder 4 adds the signals. It will not be emphasized even in
combination.
[0013]
Thus, in the delay-sum method, the sound wave coming from the target direction θ is
emphasized, and the noise coming from the other direction θN is relatively suppressed.
03-05-2019
3
[0014]
At this time, if the target direction θ is scanned and the output signal of the microphone array is
monitored, the output signal becomes large when θ is directed to the target speaker, so that the
direction of the target speaker can be searched.
Then, by emphasizing and adding the phases according to equation (4) so as to emphasize the
sound wave from the direction θ of the target speaker, that is, by aiming the directivity of the
microphone array in the direction of θ, the target sound is high. Sound can be picked up with
the SN ratio.
[0015]
Here, for convenience of explanation, although it has been described that a plurality of
microphones are arranged on a straight line at equal intervals d, the microphones may be
arranged at irregular intervals, and the arrangement shape is also two-dimensional · 3 You may
arrange in dimension.
[0016]
Also, as shown in FIG. 8, when the point sound source S is located at a relatively short distance to
the array, the delay elements 31, 32, ..., using the spherical wave property from the sound source
S. It is important to improve the sound collection SN ratio by providing gains 71, 72,..., 7M in the
latter stage of 3M and applying appropriate loads to these gains.
There is a way of giving the load as expressed by the following formulas (5), (6) and (7) (Nomura,
Kanada, Kojima "Near Field Microphone Array", Journal of the Acoustical Society of Japan, 53
Volume 2 (1997), pp. 110-116).
[0017]
Here, r1, r2, ..., rM are distances from the sound source S to the respective microphones 21, 22,
..., 2M, rC is the critical distance in the room, that is, the direct sound power and the
reverberation power of the sound source become equal The distance is expressed by rC = 表 わ
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4
(0.0032 V / T) with respect to the room volume V [m 3] and the room reverberation time T
[seconds] (H. Kuttruff, Room Acoustics (Third Edition) , Elsevier Applied Science, pp. 100-132
(1991)).
At this time, the microphone array is most sensitive to the point of the position of the sound
source S, and so to speak, the focus of the sensitivity is formed.
At this time, with respect to the distances ri (i = 1, 2,..., M) to the respective microphones, the
delays D.sub.0 -ri / c (c: sound speed) of the delay devices 31, 32,. If the sensitivity focus is
scanned by changing g0, that is, a, and the array output is monitored, the array output becomes
larger when the sensitivity focus is directed to the point where the target speaker exists. You can
find the position.
[0018]
Thus, the target sound can be picked up with a high sound collection SN ratio by finding the
existence area of the target speaker as the direction or position and directing the directivity of
the array to the existence area.
[0019]
It is attempted to apply this microphone array 1 to a communication conference such as a video
conference.
The advantage of using the microphone array 1 for the sound collection unit of a communication
conference is that the microphone array 1 can be installed at a position separated from the
speaker with a high sound collection SN ratio, so multiple microphones are installed on the desk
There are advantages such as not being aware of the microphone, not being aware of the
microphone, and enabling natural communication.
[0020]
An example of a communication conference apparatus in which the microphone array 1 is used
as a sound pickup unit is shown in FIG.
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5
In this figure, 10A and 10B indicate communication conference rooms, 11A and 11B indicate
microphone arrays, 12A and 12B indicate microphone array main devices, 13 indicates
communication lines, and 14A and 14B indicate speakers.
The target voice uttered in the communication conference room 10A is picked up by the
microphone array 11A, and after processing for emphasizing the target voice in the microphone
array main device 12A, the communication conference which is the communication destination
through the communication line 13 It is transmitted to the room 10B and emitted from the
speaker 14B as a received voice.
The flow of signals for the target voice uttered in the communication conference room 10B is
also the same flow as described above. As described above, the microphone array main units 12A
and 12B scan the directivity of the microphone arrays 11A and 11B to find the existence area of
the target speaker, and the directivity of the microphone arrays 11A and 11B is directed to the
existence area of the target speaker It operates in such a way as to pick up the target voice at a
high SN ratio.
[0021]
As described above, the microphone arrays 11A and 11B detect the presence area of the target
speaker, direct the directivity of the microphone arrays 11A and 11B to the presence area, and
collect the target sound at a high SN ratio. there were. However, when the reception voice from
the communication destination is radiated from the reception speaker 14A or 14B, the reception
speaker 14A or 14B is often erroneously detected as the target speaker, and the directivity of the
microphone array 11A, 11B is received by the reception speaker 14A. Or it turned out that it
turned to the direction of 14B.
[0022]
As a method of avoiding this, it is conceivable to detect a state in which a sound is emitted from
the reception speaker 14A or 14B (reception detection), and in the reception state, to stop the
detection of the presence region of the target speaker. . Reception detection performs
determination based on, for example, the magnitude of the level of the electrical signal supplied
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to the reception speaker. However, in this method, if the position of the target speaker is detected
immediately after the end of the reception, the area near the reception speaker is erroneously
detected as the target speaker position.
[0023]
[Means for Solving the Problems] First, the results of analysis of the causes of the above
problems will be described. Usually, the position detection of the target speaker is performed as
follows. The output power when the directivity of the microphone array is directed to a certain
area (focus) can be considered as the power of the sound emitted from the sound source present
in that area. Therefore, if the directivity of the microphone array is scanned in the room and the
output power for each region is calculated, it is possible to obtain an estimate of the distribution
of the power of the sound source in the room. Then, it is fundamental to determine the region of
maximum power at that time as the target speaker position. Now, when calculating the output
power of the microphone array, it is usual to perform time averaging to reduce calculation errors.
This averaging time is performed in several hundred milliseconds to several seconds. As a basic
method of directivity control, power calculation including directivity scan and averaging scan is
usually performed to find the maximum power area. Then, reception detection is performed, and
when it is determined not to be reception, the area of the maximum power is determined as the
target speaker position, and the directivity for sound collection is directed in the direction of the
area. On the other hand, when it is determined to be in the receiving state, the region of
maximum power is considered to be (or near) the receiving speaker direction, so the directivity
for sound collection is not directed in that direction. However, as described above, since the
power is a time average value, the average value of the output power with respect to the vicinity
of the reception speaker is a high value immediately after the end of the reception. Therefore, if
the target speaker position detection is performed immediately after the end of the reception, the
position near the reception speaker is erroneously determined as the speaker position. This is the
cause of the above-mentioned problems to be solved. In the present invention, in order to solve
this problem, the following method is adopted based on the above cause analysis.
[0024]
First, in order to distinguish the target voice emitted by the target speaker from the reception
voice radiated from the reception speaker, a reception detection unit for detecting a reception
state in which the reception voice is present is provided. Then, while the reception detection unit
determines that the reception is being performed, a measure is taken to stop or reset the power
calculation for the microphone array output of the reception speaker or the region in the vicinity
03-05-2019
7
of the reception speaker or the reception speaker. In this way, it is possible to prevent the power
calculation from being influenced by the received voice emitted from the received speaker, so
that the received speaker or the area near the received speaker is not erroneously detected as the
target speaker position. In addition, since the entire area of the target area is scanned and
detected when not receiving voice, even if the target speaker speaks near the speaker, its position
can be detected and the directivity can be directed to the target speaker, resulting in good
collection. Sound can be realized.
[0025]
In addition, since the last power remains when the power calculation is only stopped, this method
may be used when a speech is expected at the immediately preceding speech position or in the
vicinity thereof at the time of resuming the power calculation. If you want to remove the
influence of the power that was uttered immediately before, reset the power value to zero or a
specified value.
[0026]
If the power calculation for the entire area of the directivity to be scanned is stopped or reset, the
detection of the speaker is not performed during the reception state, but if the target of the stop
or reset is limited to the reception speaker or the reception speaker near region The speaker
detection is also performed during the reception state.
[0027]
Note that the area near the reception speaker is an area of about 0.5 to 2 m in radius centered on
the reception speaker, and the actual size of the radius is the application of sound collection, the
degree of reflection of the room used, noise, etc. It is decided depending on the condition.
However, it is desirable that the size be as large as possible without overlapping with the target
speaker's presence area.
[0028]
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8
The most basic method of earpiece detection is to monitor an electrical earpiece signal sent from
the other party. Reception detection can be performed, for example, by calculating the power of
the received electric signal and determining whether the power exceeds a threshold th1. More
complicated reception detection methods can use reception detection techniques used in, for
example, voice switch technology and acoustic echo canceller technology.
[0029]
As described above, reception detection is performed, power calculation stop or reset control for
target sound source presence area estimation as described above is performed, a target sound
source presence area is estimated, and the target sound source presence area is described above.
By performing such directivity control, it is possible to prevent an operation in which the
directivity of the microphone array is erroneously directed to the area where the reception
speaker is present even after the reception speaker has finished emitting the reception voice.
[0030]
When the sound pressure of a specific area in the room other than the area near the reception
speaker is increased by reflection of the reception sound radiated from the reception speaker in
the room, the specific area is also combined with the reception speaker or the area near the
reception speaker. Set to stop or reset power calculation.
[0031]
The above-mentioned method of detecting the reception state and preventing the directivity of
the array from being directed to the reception speaker or the reception speaker near area or the
set specific area is to pick up the speech of the speaker and have the speaker The present
invention can also be applied to in-field loud-speaking in which loud-speaking speakers and the
like are used in the same room.
For example, when a listener asks a question to a speaker at a lecture in a relatively large venue,
etc., the question of the listener is expanded into the venue by a speaker for loud-speaking to
make it easy to listen to the contents of the question.
When picking up questions of the listener, it is conceivable to use the above-mentioned
microphone array to direct directivity to the audience, but if the energy of the sound wave
emitted from the loudspeaker for loudening is large, the microphone array will ask the question
03-05-2019
9
There is a possibility that a speaker for loud sound may be misdetected as a speaker other than
the listener who is doing. In order to prevent this, there can be considered a method of
controlling directivity except for a loudspeaker for loudspeaker or a region near the loudspeaker
for loudspeaker or a set specific region.
[0032]
In addition, although the method is described here as the method of excluding the influence on
the power calculation of the reception voice emitted from the reception speaker, this method is
not limited to the reception speaker, and an arbitrary unnecessary sound source intermittently
generates an unnecessary sound. The present invention can also be applied to applications in
which the directivity of the microphone array is accurately directed in the direction of the target
voice under the environment and collected. That is, a designated area sound pickup unit for
forming directivity in an unnecessary sound source generating unnecessary sound or an
unnecessary sound source near area or a designated specific area is provided, and the sound
wave of the unnecessary sound source is based on the output signal of the designated area sound
pickup unit. An unnecessary sound source operating state is detected by the unnecessary sound
source operating state detection unit, and power calculation of the scanned directivity output is
stopped or reset in order to search for a target sound source while the unnecessary sound source
operating state is detected. do it.
[0033]
According to a method of detecting a target sound source area according to the present
invention, a sound pickup apparatus comprising: a microphone array comprising a plurality of
microphones; and a microphone array main device for processing an output signal of the
microphone array. In the target sound source area detection method, the directivity of the
microphone array is scanned, the scan directivity output power is calculated from the output
signal for the scanned directivity, and the specific sound source operation in which the sound
wave of the specific sound source is emitted. Detects the state and controls the calculation of the
scan directivity output power while the specific sound source operating state is detected to
calculate the scan directivity output power for the entire area of the scanned directivity or a
specific setting area And reset the microphone array to a specified value, and the directed area of
the microphone array directivity when the calculated scan directivity output power is at a
maximum. The a configuration that is estimated to be present area of the target sound source.
[0034]
Further, the present invention is applied to the communication conference apparatus.
03-05-2019
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[0035]
According to the target sound source area detection device of the present invention, a reception
detection unit for detecting a reception state in which reception speech is present is provided,
and the power calculation unit calculates the power of the directivity for scanning by the
directivity scanning unit. While the reception detection unit is detecting the reception state, the
reception calculation speaker stops or resets the power calculation to a specified value for the
entire area of the directivity or a specific setting area scanned. It is possible to prevent the
influence of the received speech radiated from the power calculation.
Therefore, by using the power calculated by the power calculation unit under such control, the
target sound source region estimation unit estimates the directed region of the directivity of the
microphone array when the power is maximum. The target sound source area can be accurately
detected by preventing the influence of false estimation due to the received voice emitted from
the receive speaker.
The detected target sound source area can be used, for example, for control for accurately
directing the directivity of the array to the target sound source without the influence of the
reception voice emitted from the reception speaker.
[0036]
In addition, in an environment where an arbitrary unnecessary sound source generates an
unnecessary sound intermittently as well as the reception speaker, the influence of the
unnecessary sound is prevented to accurately direct the microphone array in the area where the
target sound source exists. It can also be used for the purpose of picking up the sound. In this
case, a designated area sound pickup unit for forming directivity in the unnecessary sound
source or a region near the unnecessary sound source or designated area is provided, and the
sound wave of the unnecessary sound source is emitted based on the output signal of the
designated area sound pickup unit. Specific sound source operating state is detected by the
specific sound source operating state detection unit, and while the specific sound source
operating state is detected, the power calculation in the power calculation unit is performed, or
the entire area of directivity scanned as described above Stop the power calculation for a specific
setting area or reset it to the specified value. In this way, it is possible to prevent the influence of
03-05-2019
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unnecessary sound and to pick up the directivity of the microphone array accurately in the area
where the target sound source is present.
[0037]
Embodiments of the present invention will be described below with reference to the drawings.
[0038]
FIG. 1 is a block diagram showing the configuration of the first embodiment of the present
invention.
In this figure, 20 indicates a target sound source area detection device according to the present
invention, and 30 indicates a sound collection device. The sound pickup device 30 comprises a
microphone array 31, a microphone array main unit 32, and a microphone array main unit
output terminal 33. The target sound source area detection device 20 includes a designated area
sound pickup unit 21, a specific sound source operation state detection unit 22, a directivity scan
unit 23, a power calculation control unit 24, a power calculation unit 25, and a sound source
existing area estimation unit 26. And a sound source existing area output terminal 27.
[0039]
Next, the operation will be described. The designated area sound pickup unit 21 directs
directivity to a designated area such as an area where a specific sound source such as an
unnecessary sound source emitting an unnecessary sound is present using the signal collected by
the microphone array 31, and the specific sound source operating state The detection unit 22
uses the output of the designated area sound collection unit 21 to detect the specific sound
source operating state in which the specific sound source emits a sound. The directional scanning
unit 23 scans the directivity of the microphone array using the signal collected by the
microphone array 31, and the power calculation unit 25 calculates the power of the output with
respect to the scanned directivity. At this time, in order to remove the influence of the sound
emitted from a specific sound source (air conditioner, refrigerator, etc.) on the power calculation,
when the specific sound source operating state is detected, the power calculation in the power
calculation unit 25 is performed by the power calculation control unit 24. Is reset to a stop or
designated value for all areas scanned by the directional scanning unit 23 or a specific set area.
The sound source presence area estimation unit 26 estimates the presence area of the target
03-05-2019
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sound source from the output signal of the power calculation unit 25. The estimated presence
area of the target sound source is output from the sound source existing area output terminal 27.
[0040]
FIG. 2 shows a second embodiment of the present invention. In this embodiment, the designated
area power calculator 221 which calculates the power of the output signal of the designated area
sound pickup unit 21 and the power calculated by the designated area power calculator 221
determine whether the power exceeds the set threshold. The specific sound source operating
state detection unit 22 is configured of the specific sound source operating state determination
unit 222.
[0041]
FIG. 3 shows a third embodiment of the present invention. In this embodiment, a comparison
sound pickup unit 28 for directing the directivity of the microphone array 31 is provided in the
near area of directivity formed by the designated area sound pickup unit 21, and the designated
area sound pickup unit from the designated area sound pickup unit 21 The specific sound source
operating state detection unit 22 detects the specific sound source operating state using the
output signal and the comparison sound pickup unit output signal from the comparison sound
pickup unit 28.
[0042]
FIG. 4 shows a fourth embodiment of the present invention. In this embodiment, a designated
area power calculator 221 for calculating the power of the output signal from the designated
area pickup unit 21 and a comparison power calculator 224 for calculating the power of the
output signal from the comparison pickup unit 28 are used. A designated area power gradient
determination unit that determines whether the designated area sound collection signal power
calculated by the designated area power calculation unit 221 exceeds the comparison sound
collection signal power calculated by the comparison power calculation unit 224 by a set value A
specific sound source operating state detection unit 22 is configured of a designated area power
determination unit 223 that determines whether the designated area sound collection signal
power has exceeded the set threshold, and the specific sound source operating state
03-05-2019
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determination unit 222. When the determinations of the designated area power gradient
determination unit 225 and the designated area power determination unit 223 are both true, the
specific sound source operating state determination unit 222 determines that the specific sound
source is active. It is determined Example state.
[0043]
FIG. 5 shows a fifth embodiment of the present invention. In this figure, reference numeral 40
denotes a communication conference apparatus, which comprises a sound collection device 30, a
target sound source area detection device 20, a receiving terminal 41, and a receiving speaker
42. Others are the same as FIG. 1, FIG. 2 grade ¦ etc.,. The target sound source area detection
device 20 includes a reception state detection unit 28 including a reception signal power
calculation unit 281 and a reception state determination unit 282, a power calculation control
unit 24, a directivity scan unit 23, a power calculation unit 25, and a sound source presence. A
region estimation unit 26 and a sound source existing region output terminal 27 are provided.
[0044]
To explain the operation, the reception signal input to the reception terminal 41 is emitted from
the reception speaker 42 as a reception sound wave. The directivity scanning unit 23 scans the
directivity using the output signal of the microphone array 31, the power calculation unit 25
calculates the power of the output for the scanned directivity, and the sound source existing area
estimation unit 26 calculates the power of the output. Estimate the presence area of the target
sound source from the power. At this time, the reception state detection unit 28 detects the
reception state and the power calculation control unit 24 detects the reception state while the
reception state is detected in order to avoid the influence of the reception voice emitted from the
reception speaker 42 on the power calculation. The power calculation at 25 is controlled to be
reset to a stop or designated value for all areas scanned by the directional scanning unit 23 or a
specific set area. In the detection of the reception state, the reception signal power calculation
unit 281 calculates the power of the reception signal, and when the calculated power of the
reception signal exceeds a set threshold, the reception state determination unit 282 determines
the reception state. It is detected as determined. In this way, the reception voice emitted from the
reception speaker 42 prevents the influence exerted on the power calculation for estimating the
presence area of the target sound source, and the sound source presence area estimation unit 26
can accurately detect the presence area of the target sound source. Become. The presence area of
the detected target sound source is output from the sound source existing area output terminal
27.
03-05-2019
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[0045]
FIG. 6 shows a sixth embodiment of the present invention. In this embodiment, a band filtering
section 29 is provided for extracting a specific band component of the output signal of the
reception signal. Others are the same as FIG. This embodiment is intended to remove low
frequency electrical noise when it is not possible to detect the receiving condition well, for
example, because low frequency electrical noise is unnecessary to the electrical incoming signal. ,
And a band-pass filter that extracts high-frequency components to detect a reception state well.
[0046]
As described above, the target sound source area detection method according to the present
invention comprises a microphone array comprising a plurality of microphones, and a
microphone array main device for processing the output signal of the microphone array. In a
method of detecting a target sound source area of a sound device, the directivity of the
microphone array is scanned, a scan directivity output power is calculated from an output signal
for the scanned directivity, and a sound wave of a specific sound source is emitted. A specific
sound source operating state is detected, and while the specific sound source operating state is
detected, the calculation of the scan directivity output power is controlled to scan the directivity
of the entire area or the specific setting area of the scan. The directivity of the microphone array
when the power calculation is stopped or reset to a specified value and the calculated scan
directivity output power is at a maximum Because and estimating the presence area of the target
sound source area directed, can accurately sound detection. Then, the present invention is
similarly applied to the communication conference apparatus, and in this case, the reception
signal is used.
[0047]
Further, the target sound source area detection apparatus according to the present invention
includes a reception detection unit that detects a reception state in which reception speech is
present, and performs power calculation of output with respect to directivity scanned by the
directivity scanning unit. While the receiver detection unit is detecting the reception state, the
power calculation control unit stops the power calculation for the entire area of the directivity or
the specific setting area scanned, or resets the power calculation to the designated value. It is
03-05-2019
15
possible to prevent the influence of the received speech radiated from the speaker on the power
calculation. Therefore, using the power calculated by the power calculation unit under such
control, a target sound source area estimation unit has a target sound source area in which the
directivity of the microphone array is maximized when the power becomes maximum. By
estimating the region as a region, it is possible to prevent the influence of false estimation due to
the received speech radiated from the reception speaker, and to accurately detect the target
sound source region. The detected target sound source area can be used, for example, for control
for accurately directing the directivity of the array to the target sound source without the
influence of the reception voice emitted from the reception speaker. Therefore, the directivity of
the array can be accurately directed to the target sound source, and even when the target sound
source does not emit the target sound, the directivity of the array to the reception speaker can be
obtained by the reception voice from the reception speaker. There is an unprecedented superior
effect that it is possible to prevent the motion of turning.
[0048]
In addition, in an environment where an arbitrary unnecessary sound source generates an
unnecessary sound intermittently as well as the reception speaker, the directivity of the
microphone array is accurately prevented in the area where the target sound is emitted by
preventing the influence of the unnecessary sound. It becomes possible to pick up the sound,
prevents the operation of directing the directivity of the array to the area where the unnecessary
sound exists by mistake due to the influence of the unnecessary sound even while the target
sound is not emitted, The directivity of the microphone array is accurately directed to the
existing area, and only the target sound can be picked up with a high S / N ratio, which is an
unprecedented advantage.
[0049]
Brief description of the drawings
[0050]
1 is a block diagram showing the configuration of a first embodiment of the target sound source
area detection device of the present invention.
[0051]
2 is a block diagram showing the configuration of a second embodiment of the target sound
source area detection device of the present invention.
03-05-2019
16
[0052]
3 is a block diagram showing the configuration of a third embodiment of the target sound source
area detection device of the present invention.
[0053]
4 is a block diagram showing the configuration of a fourth embodiment of the target sound
source area detection device of the present invention.
[0054]
5 is a block diagram showing the configuration of a fifth embodiment of the target sound source
area detection device of the present invention.
[0055]
6 is a block diagram showing the configuration of a sixth embodiment of the target sound source
area detection device of the present invention.
[0056]
7 is a diagram for explaining the principle of noise suppression and sound collection by the
conventional delay and sum method.
[0057]
FIG. 8 is a view for explaining that the load of the gain at the rear stage of the delay unit is
appropriately set to improve the sound collection SN ratio when the sound source is located at a
position close to the microphone array.
[0058]
9 is a diagram for explaining a communication conference using a conventional microphone
array.
[0059]
Explanation of sign
[0060]
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20 target sound source area detecting device 21 specified area sound collecting section 22
specified sound source operating state detecting section 221 specified area power calculating
section 222 specified sound source operating state determining section 223 specified area power
determining section 224 comparison power calculating section 225 specified area power
gradient determination Unit 23 directivity scanning unit 24 power calculation control unit 25
power calculation unit 26 sound source presence area estimation unit 27 sound source presence
area output terminal 28 sound pickup unit for comparison 29 band filtering unit 30 sound
collection device 31 microphone array 32 microphone array main device 33 Microphone array
device output terminal 40 Communication conference device 41 Receiving terminal 42 Receiving
speaker
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