close

Вход

Забыли?

вход по аккаунту

?

JP2008294690

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2008294690
An audio conference apparatus in which a plurality of units each having a microphone and a
speaker are mutually connected, the occurrence of howling is efficiently prevented. SOLUTION:
The level of an audio signal in the direction of a sound collecting area which is a target direction
is compared with the level of an audio signal in the direction of an adjacent area which is an off
target direction. When it can be determined that the level of the audio signal in the collection
area direction is higher than the level of the audio signal in the adjacent area and it is determined
that the microphone is collecting the target audio signal, this audio signal is output from the line
output unit to the outside Do. On the other hand, when it can be determined that the level of the
audio signal in the adjacent area direction is higher than the level of the audio signal in the sound
collecting area direction and the microphone is picking up an unintended sound signal, the sound
signal is not output. [Selected figure] Figure 2
Audio conference apparatus and audio conference system
[0001]
The present invention relates to an audio conference apparatus for a large conference room
configured by connecting a plurality of units each having a microphone and a speaker.
[0002]
An audio conference apparatus for performing an audio conference by connecting a remote
conference room via a communication line or a network has been put to practical use (for
example, Patent Document 1).
04-05-2019
1
This type of audio conference apparatus, as shown in FIG. 1, includes a microphone and a
speaker, picks up the audio of its own room with the microphone, and transmits it to the audio
conference apparatus of the other party's conference room (other party apparatus) It is a device
that reproduces the sent voice (voice of the other party's conference room) with a speaker. That
is, the microphone 501 of the own apparatus 500 which is the audio conference apparatus in the
own room is connected to the speaker 512 of the other apparatus via the communication line
(network) 520 and the microphone 511 of the other apparatus 510 is connected via the
communication line (network) 520 It connects to the speaker 502 of its own device 500. The
echo canceler 503 (513) is emitted from the speaker 502 (512) by removing the signal
component emitted from the speaker 502 (512) among the signal components collected by the
microphone 501 (511). The processing unit is configured to prevent an echo from being picked
up by the microphone 501 (511) and sent back to the other device 510 (500).
[0003]
As described above, the audio conference apparatus is an apparatus for performing
teleconferencing via a communication line or a network, but using this function, a speaker
system has been proposed that uses the same space, such as a wide conference room. ing. In a
loudspeaker system, a plurality of voice conference devices are installed in the same space and
connected to each other by a cable, and voices collected by a microphone of a certain voice
conference device are output as loud voices from speakers of other voice conference devices The
connection configuration is the same as that shown in FIG. 1 except that the communication line
(network) is replaced with a cable.
[0004]
Unexamined-Japanese-Patent No. 2004-343668
[0005]
However, as described above, when the audio conference apparatus is used for a loudspeaker
system in the same space, there is a problem that howling tends to occur because the
microphone and the speaker are on within the range where the direct sound can reach.
04-05-2019
2
In addition, it is also conceivable to turn on the microphone only among the plurality of audio
conference devices that have detected the speech of the meeting attendee, but when the audio
conference devices are installed in proximity, one conference There was a problem that the
microphones of a plurality of devices were turned on by the utterance of the attendee, and many
howling paths were formed.
[0006]
An object of the present invention is to efficiently prevent occurrence of howling in an audio
conference apparatus in which a plurality of units each having a microphone and a speaker are
connected to one another.
[0007]
According to the first aspect of the present invention, a main sound pickup unit that picks up
sound coming from a sound pickup area, a side sound pickup unit that picks up sound coming
from an adjacent area adjacent to the sound pickup area; A sound emitting unit for sound, a line
output unit for outputting an audio signal to the outside, a line input unit for inputting an audio
signal from the outside, and a level of a main sound collecting signal which is an audio signal
collected by the main sound collecting unit. An audio conference comprising the signal
processing unit for supplying the main sound collection signal to the line output unit when the
level of the side sound collection signal which is the sound signal collected by the side sound
collection unit is higher than the level of the side sound collection signal It is an apparatus.
[0008]
The above invention includes one or more line output units and line input units.
If it is one pair, two devices can be connected back and forth. If two or more pairs are provided,
three or more devices can be connected by ladder connection, and many voice conference
devices are connected to each other. Enables large-scale system configuration.
Here, the main sound pickup unit picks up the sound coming from the sound pickup area, and
the side sound pickup unit picks up the sound coming from the adjacent area. In a form in which
a plurality of audio conference devices are connected to each other and used, it is assumed that
each audio conference device is used by a small number of one or two people. In this case, it is
usually considered that one or two meeting attendees in charge of each device are seated in the
04-05-2019
3
front direction of the device. Therefore, the sound collection area is typically set to an angular
range or plane-spatial range in the front direction of the device, and the adjacent area is set to an
angle range or a plane-spatial range adjacent to the sound collection area Be done.
[0009]
If the level of the audio signal in the sound collection area direction is higher than the level of the
audio signal in the adjacent area direction, it is determined that the meeting attendee in charge
has uttered, and the audio signal is supplied to the line output unit. On the other hand, when the
level of the audio signal in the adjacent area direction is higher than the level of the audio signal
in the sound collecting area direction, it is determined that the next meeting attendee has uttered,
and the audio signal is not supplied to the line output unit.
[0010]
According to a second aspect of the present invention, in the first aspect, the main sound pickup
unit and the side sound pickup unit are formed by sound pickup signals of a microphone array
configured by arranging a plurality of microphones in an array. The sound beam is used to
collect voices coming from the sound collecting area and the adjacent area, respectively.
[0011]
In the invention of claim 2, the microphone array is used to form a plurality of sound collection
beams.
And each sound collection beam is allocated to the said main sound collection part and a side
sound collection part. As a result, it is not necessary to fixedly provide the main sound pickup
unit microphone and the side sound pickup unit microphone, and the degree of freedom in
setting the sound pickup area and the adjacent area can be increased.
[0012]
The invention according to claim 3 is characterized in that the voice conference device is a unit,
and a plurality of units are coupled by mutually connecting the line input unit and the line output
unit.
04-05-2019
4
[0013]
In the present invention, a plurality of voice conference apparatuses (units) according to claims 1
and 2 are mutually connected, and while each other unit mutually transmits voice signals, voices
in the direction of the sound collection area that each unit takes charge of Responsible for sound
collection and sound emission in approximately the same direction.
Thus, sound emission and collection in a large conference room can be efficiently performed, and
unnecessary sound collection can be prevented, so that howling in the case of a large number of
connections can be efficiently prevented.
[0014]
The invention of claim 4 is an audio conference system in which a plurality of the audio
conference devices are connected via a network or a communication line.
[0015]
According to the present invention, in a plurality of conference rooms, it becomes possible to
perform an amplification using a plurality of units, so that it is possible to hold a large-scale
conference between large conference rooms.
[0016]
According to the present invention, when the level of the audio signal arriving from the adjacent
area direction which is the direction other than the target is high, the audio signal arriving from
the sound collecting area direction which is the target direction is not output from the line output
terminal. Since it is possible to prevent line output of such a collected sound signal and formation
of an unnecessary howling path, it is possible to efficiently prevent the occurrence of howling.
[0017]
A voice conference apparatus according to an embodiment of the present invention will be
described with reference to the drawings.
[0018]
FIG. 2 (A) is a schematic block diagram of the audio conference apparatus according to the
04-05-2019
5
present invention, and FIG. 2 (B) is an audio conference system (speaker system) configured by
connecting a plurality of such audio conference apparatuses (three in FIG. Is a diagram showing a
schematic configuration of.
[0019]
As shown in FIG. 6A, the audio conference apparatus has two line input terminals and two line
output terminals for audio signals.
The line input terminal InL is a terminal for inputting an audio signal output from the audio
conference device adjacent on the left side.
The line input terminal InR is a terminal for inputting an audio signal output from an audio
conference device adjacent on the right side.
Further, the line output terminal OutL is a terminal for outputting an audio signal to the audio
conference device adjacent on the left side.
The line output terminal OutR is a terminal for outputting an audio signal to an audio conference
device adjacent on the right side.
[0020]
By providing two line input terminals and two line output terminals of the audio signal in this
manner, ladder connection of three or more audio conference apparatuses as shown in FIG.
[0021]
The audio signals input from the line input terminals InL and InR are additively synthesized by
the adder 106 and emitted from the speaker 102 through the signal processing unit 103.
As a result, voice signals (line input voice signals) input from the left and right voice conference
04-05-2019
6
devices can be synthesized and emitted from the speaker 102.
[0022]
Further, the audio conference apparatus is provided with three types of microphones 101C,
101L, and 101R.
Hereinafter, the microphone 101C is called a main microphone, and the microphones 101L and
101R are called side microphones. The main microphone 101C picks up the sound coming from
the sound pickup area. Here, the sound collection area is an area in which each of the voice
conference devices 100A, 100B, and 100 C is in charge of sound collection, and generally, an
area including the front of the device is allocated.
[0023]
The side microphone 101L and the side microphone 101R are areas adjacent to the sound
collection area outside the sound collection area (hereinafter referred to as adjacent areas). Pick
up the voice of). The left side microphone 101L picks up the adjacent area sound on the left side
of the sound collection area, and the right side microphone 101R picks up the sound on the right
side of the sound collection area. These three types of microphones may be configured with
separate hardware, and a plurality of sound collection beams formed using one set of
microphone arrays (hardware) may be used as the respective microphones.
[0024]
Note that the sound collection area and the adjacent area may be defined by an angular range
from the microphone, or may be defined by a planarly or spatially divided range. This is
determined by the installation direction and directivity of each microphone.
[0025]
Hereinafter, the sound signal of the sound collection area collected by the main microphone
04-05-2019
7
101C is referred to as a main sound collection signal. This main sound pickup signal is an audio
signal externally output from the line output terminal OutL / R. Also, the audio signal of the
adjacent area input from the side microphone 101L and the side microphone 101R is referred to
as a side sound collection signal. The side sound pickup signal is used to determine whether the
main sound pickup signal picked up by the microphone 101C is a target sound signal or a
wraparound signal from an adjacent area.
[0026]
The audio signals collected by the microphones 101C, 101L, and 101R are input to the signal
processing unit 103, respectively. The signal processing unit 103 compares the levels of the
audio signals (main sound pickup signal and side sound pickup signal) input from the main
microphone 101C and the side microphones 101L and 101R, and lines the main sound pickup
signals based on the comparison result. It is determined whether to output (output from the line
output terminal OutL / R). That is, the level of the main sound pickup signal is compared with the
level of the left and right side sound pickup signals, and if the level of the main sound pickup
signal is higher than the level of the side sound pickup signal, the main sound pickup signal is
This main sound pickup signal is line-outputted via the mixers 105L and 105R on the
assumption that it is the voice of the meeting attendee who is seated and is not a wraparound
voice from the adjacent area. On the other hand, if the level of the side sound pickup signal is
higher than the level of the main sound pickup signal, the main sound pickup signal is a
wraparound sound from the adjacent area and the voices of the conferees seated in the sound
pickup area. If not, do not line out the main sound pickup signal.
[0027]
Note that the state in which the main sound pickup signal is line output is referred to as
microphone on, and the state in which the main sound pickup signal is not line output is referred
to as microphone off.
[0028]
With the above-mentioned function, in the figure (B), the audio conference apparatus 100B
outputs the audio signal in a line (microphone on) only when the conference attendee 200B
utters, and the pronunciation voices of the conference attendees 200A and 200C are rotated.
Even if the sound is picked up by the respective main microphones 101C, this is not line output
(microphone off).
04-05-2019
8
In addition, the speech of the meeting attendee 200B is collected not only by the main
microphone 101C of the audio conference device 100B but also by the main microphone 101C
of the audio conference devices 100A and 100C due to a wraparound, but only the audio
conference device 100B The audio signal is output in line, and the left and right audio conference
devices 100A and 100B do not output the audio signal in line.
[0029]
Thus, each audio conference apparatus turns on the microphone only when the conference
attendee who is in charge of the apparatus (in the audio collection area of the own apparatus)
speaks, and the conference attendee outside the audio collection area (the audio conference
apparatus next to Microphones can not be turned on by the speech of the meeting attendee in
charge, and unnecessary microphones can be reduced to reduce the risk of howling.
[0030]
In addition, when one conference attendee speaks, only the audio conference device in charge of
the conference attendee makes a microphone on, and the adjacent audio conference device
remains a microphone off, so one for one utterance Only the audio conference device can be
microphone-on, and unnecessary microphone-on can be reduced to reduce the risk of howling.
[0031]
Here, when the microphone is on, the signal processing unit 103 of the audio conference device
inputs an audio signal collected by the main microphone 101C to the mixers 105L and 105R.
The audio signal input to the line input terminal InR from the audio conference apparatus
adjacent on the right side is further input to the mixer 105L.
The mixer 105L mixes these audio signals with an appropriate balance and outputs the mixed
signal to the left line output terminal OutL. Further, the audio signal input to the line input
terminal InL from the audio conference apparatus adjacent on the left side is further input to the
mixer 105R. The mixer 105R mixes these audio signals with an appropriate balance and outputs
the mixed signal to the right line output terminal OutR.
04-05-2019
9
[0032]
The audio signal output to the left line output terminal OutL is input to the adjacent audio
conference device on the left side. The audio signal output to the right line output terminal OutR
is input to the audio conference device adjacent on the right side.
[0033]
In the connection form of the ladder shown in the figure (B), each audio conference device is
implemented by bucket relaying the audio signal from left to right and right to left while adding
the collected sound signal of the own device as described above. In this case, signals collected by
any of the audio conference devices connected by ladder are always input.
[0034]
FIG. 2 shows a schematic configuration of the audio conference apparatus and the audio
conference system according to the present invention. The configuration and operation of the
audio conference apparatus and the audio conference system will be described in more detail
with reference to FIG.
[0035]
FIG. 3 and FIG. 4 are views showing the appearance of the voice conference device.
FIG. 3 is an external perspective view of the voice conference apparatus, and FIGS. 4A, 4B, and 4C
are a front view, a bottom view, and a rear view, respectively.
Although three microphones 101 and one speaker 102 are illustrated in the above schematic
configuration, an actual audio conference apparatus is provided with two microphone arrays
each of 16 provided on the front and back sides of the housing as the microphones. While being
equipped (see FIG. 4 (A) and (C)), the speaker array of one row (16 pieces) provided on the
bottom of the case as a speaker is provided (see FIG. 4 (B)).
[0036]
04-05-2019
10
In the description of this embodiment, the surface shown in FIG. 4A (longitudinal side surface
shown in FIG. 3) is referred to as the front, front or front side of the audio conference device
(housing). The surface shown in 2.) is called the back, back or back side of the audio conference
device (housing). Therefore, the right end of FIG. 4 (A) is the right side, and the left end is the left
side. The right side is the short side shown in FIG.
[0037]
In FIG. 3, the audio conference device 1 includes a housing 112, a leg 113, and an operation unit
114. The housing 112 is formed in a substantially rectangular shape elongated in the left-right
direction, and legs 113 are provided at both left and right ends. The legs 113 support the
housing 112 in a state of being lifted a predetermined height from the installation surface of the
conference desk or the like. In the following description, among the four side surfaces of the
housing 112, the front and rear side surfaces are referred to as long surfaces, and the left and
right side surfaces are referred to as short surface.
[0038]
At the right end of the top surface of the housing 112, an operation unit 114 including an LCD
display 41 and a plurality of buttons 42 is installed. The operation unit 114 is connected to the
main control unit 10 installed in the housing 112. The operation button 42 receives the
operation input of the meeting attendee and transmits it to the main control unit 10. The LCD
display displays the operation content, the execution mode, and the like.
[0039]
An input / output terminal group is embedded in the right side surface of the housing 112. That
is, a network connection terminal 61 to which a network cable is connected, line output terminals
62L, R (OutL, R) as audio input / output terminals, and line input terminals 63L, R (InL, R) are
embedded. The line output terminals 62L, R (OutL, R) and the line input terminals 63L, R (InL, R)
may be analog signal terminals such as pin jacks or digital audio terminals such as optical fibers.
Although not shown, a power supply terminal for connecting to a power supply is also embedded
in the right side surface.
04-05-2019
11
[0040]
On the lower surface of the housing 112, speakers SP1 to SP16 of the same specification are
installed. The speakers SP1 to SP16 are linearly installed at regular intervals along the
longitudinal direction, and thereby a speaker array SPA is configured. On the front side of the
housing 112, microphones MIC101 to MIC116 of the same specifications are installed. The
microphones MIC101 to MIC116 are linearly installed at predetermined intervals along the
longitudinal direction, and thereby the microphone array MAF on the front side is configured.
Also, on the rear side surface of the housing 112, the microphones MIC201 to MIC216 of the
same specification are installed. The microphones MIC <b> 201 to MIC <b> 216 are also linearly
installed at predetermined intervals along the longitudinal direction, and thereby, the
microphone array MAR on the back side is configured. A lower surface grille 121 punched and
meshed is installed on the lower surface, the front side surface, and the rear side surface of the
housing 112 so as to cover the speaker array and the microphone array.
[0041]
In the present embodiment, the number of speakers in the speaker array is 16 and the number of
microphones in each microphone array is 16. However, the number of speakers and the number
of microphones may be appropriately set according to the specification without being limited
thereto. Just do it. Moreover, in this embodiment, although arrangement | positioning of the
speaker array and the microphone array was carried out at equal intervals, you may arrange |
position suitably according to a specification. For example, the aspect may be densely disposed at
the central portion along the longitudinal direction and may be disposed sparsely toward both
ends.
[0042]
FIG. 5 is a block diagram of an audio signal processing system of the audio conference device 1.
The audio conference apparatus 1 includes a main control unit 10, a mixing unit 11, a sound
emission control unit 12, a D / A converter 13, a sound emission amplifier (AMP) 14, a sound
collection amplifier (AMP) 15, an A / D converter 16, and A sound control unit 17, a howling
cancellation unit 18, an operation unit 114, speakers SP1 to SP16, microphones MIC101 to
MIC116, and MICs 201 to MIC216 are provided.
04-05-2019
12
[0043]
The microphones MIC101 to MIC116 and MIC201 to MIC216 pick up surrounding sounds
including the voices from the speakers present in the surroundings of the own apparatus, convert
them into an electrical sound collecting signal, and give it to the sound collecting amplifier 15 .
The sound collection amplifier 15 amplifies the sound collection signal and supplies it to the A /
D converter 16, and the A / D converter 16 converts the sound collection signal of analog format
into a digital signal and outputs the digital signal to the sound collection control unit 17.
[0044]
The sound collection control unit 17 performs delay processing and the like on the sound
collection signals of the microphones MIC101 to MIC116 and MIC201 to MIC216, and generates
a sound collection beam signal having strong directivity in a predetermined direction including
the direction of each meeting participant Do. For example, if sound waves arrive at the same
timing from the front to all the microphones, the audio signals output from the respective
microphones are strengthened by synthesis. On the other hand, when sound waves arrive from
directions other than this, the sound signals output from the respective microphones are
weakened by being synthesized because they have different phases. Therefore, the sensitivity of
the microphone array is narrowed in a beam shape to form the main sensitivity (sound collection
beam) only in the forward direction.
[0045]
The sound collection control unit 17 can direct the sound collection beam obliquely by giving
predetermined delay times to the audio signals output from the respective microphones. When
making the sound collection beam oblique, it is set such that an audio signal is sequentially
output from the adjacent microphone each time a predetermined time passes from one end
microphone. For example, when the sound source is present in front of one end of the
microphone array, the sound wave comes from the end closest to the sound source and the
sound wave comes last to the opposite end. A delay time is added to the voice signal of each
microphone so as to correct the propagation time difference, and then the signal is synthesized.
As a result, the voice signal in this direction is enhanced by synthesis. Therefore, by sequentially
delaying audio signals output from the microphones arranged in a line from one end to the other
04-05-2019
13
end, the sound collection beam is inclined according to the delay time.
[0046]
As shown in FIG. 7B, the sound collection control unit 17 simultaneously forms a sound
collection beam in a plurality of azimuths by performing delay synthesis processing of a plurality
of systems in parallel. In FIG. 7 (B), a main beam 300C which is a central sound collection beam
is a sound collection beam directed to the sound collection area of the audio conference
apparatus, that is, the direction of the meeting attendee in charge. It corresponds to the main
microphone 101C. In addition, the left and right side beams 300L and R, which are the left and
right sound collection beams, are directed to the area adjacent to this audio conference
apparatus, that is, toward the conference attendee whom the adjacent audio conference
apparatus takes charge. It is a beam for determination to determine whether the voice signal is
the voice voice of the meeting attendee in charge or the voice that has come around from the
side, and corresponds to the side microphones 101L and 101R of FIG. The sound collection
control unit 17 inputs an audio signal collected by the main beam 300C shown in FIG. 7B to the
mixing unit 11 when the microphone is on.
[0047]
The main beam 300C may always be formed in the front direction of the device, and it is
searched in which direction in the sound collecting area the meeting attendee in charge is
located, and the main beam in the direction of the searched meeting attendees You may make it
form 300C. Further, the main beam 300C may be a beam focused in the sound collecting
direction, or may be a beam focused in the opposite side of the sound collecting direction.
[0048]
The sound emission control unit 12 delays the input audio signal Sd to each of the speakers SP1
to SP16 by an individual time and supplies it. For example, when audio signals of the same delay
amount are simultaneously input to all the speakers, audio (sound waves) are simultaneously
output from the respective speakers. The sound waves output from the speakers propagate
radially, but these combined wavefronts become parallel and propagate only forward, that is,
sound emission beams. The components propagating in directions other than this are canceled
by combining components output from the respective speakers (due to interference), and only
04-05-2019
14
the forward component is enhanced by combining and remains as a sound emission beam.
[0049]
When voice is first output from the speaker at one end, and then voice is sequentially output
from the next speaker each time a predetermined time elapses, the combined wavefront is
inclined according to the delay time, and the sound emission beam is inclined. It can be turned.
The sound emission control unit 12 can thus control the directivity of the sound emission beam
by controlling the delay amount of the audio signal given to each speaker.
[0050]
The sound emission control unit 12 performs delay processing on the input sound signal Sd so as
to form a sound emission beam having strong directivity in the direction of the meeting
attendees, and inputs the sound signal to each D / A converter 13 . Each D / A converter 13
converts the inputted sound emission signal into an analog signal and applies it to each sound
emission amplifier 14. Each sound emission amplifier 14 amplifies the analogized sound
emission signal and outputs each speaker SP1 to SP1. Give to SP16. Each of the speakers SP1 to
SP16 emits the input audio signal.
[0051]
Here, as shown in the audio conference apparatus 1A of FIG. 8, the sound collection control unit
17 forms sound collection beams symmetrically on the front side and the back side of the
apparatus. Although only the main beam is illustrated in FIG. 8, the side beams are similarly
formed symmetrically on the front side and the back side. The sound collection control unit 17
subtracts the sound collection signal of the front side beam and the sound collection signal of the
rear side beam, and treats this difference signal as the sound collection signal of the beam. As a
result, as shown in FIG. 7A, the intruding signal from the speaker array on the lower surface of
the device and the speakers of the other audio conference devices arranged on the left and right
is canceled.
[0052]
If the sound collection signal level of the main beam 300C is higher than the sound collection
04-05-2019
15
signal level of the side beams 300L and 300R, the main control unit 10 determines that the
responsible meeting attendee is speaking and the sound collection control unit 17 In response to
this, it instructs the mixing unit 11 in the subsequent stage to output this audio signal.
[0053]
The mixing unit 11 includes mixers 111 L and 111 R and an adder 502.
The audio signal SdR input from the right line input terminal InR (63R) is input to the mixer
111L. The audio signal SdL input from the left line input terminal InL (63L) is input to the mixer
111R. The output signal of the mixer 111L is output to the left line output terminal OutL (62L),
and the output signal of the mixer 111R is output to the right line output terminal OutR (62R).
Further, when the sound collection control unit 17 is in the microphone on state, the sound
collection voice signal Ss output from the sound collection control unit 17 is input to the mixers
111L and 111R.
[0054]
Therefore, when the sound collection control unit 17 does not output an audio signal, the mixing
unit 11 outputs the audio signal SdL input from the device on the left to the device on the right
(by bucket brigade) as it is and The input audio signal SdR is output as it is to the device on the
left.
[0055]
On the other hand, when the sound collection control unit 17 outputs a sound signal, the mixer
111L superimposes the sound signal Ss picked up on the line input sound signal SdR and outputs
it to the line output terminal OutL, and the mixer 111R The voice signal Ss picked up on the lineinput voice signal SdL is superimposed and output to the line output terminal OutR.
[0056]
The adder 502 adds the audio signal SdR input from the outside and the audio signal SdL to
generate an audio signal Sd, and outputs the audio signal Sd to the sound emission control unit
12.
04-05-2019
16
A notch filter 181 of the howling canceller 18 is inserted between the adder 502 and the sound
emission control unit 12.
The howling canceller 18 includes a howling detection unit 182 and a notch filter 181. The
howling detection unit 182 performs FFT on the audio signal output from the sound collection
control unit 17 to monitor whether or not a sharp peak continues for a predetermined time or
more. If the steep peak continues for a predetermined time or more, the peak component is
determined to be the howling sound, and the notch filter 181 is set to remove the frequency
component. The notch filter 181 is a filter that sharply attenuates only a specific frequency
component of the audio signal to be filtered to a narrow band, and the notch frequency is set by
the howling detection unit 182. When the howling detection unit 182 does not detect howling,
the notch filter 181 is set so as not to function.
[0057]
The howling canceller 18 is not an essential component of the present invention. However, in
this embodiment, the howling canceller 18 is provided in order to suppress the howling more
efficiently.
[0058]
In this embodiment, two lines (two pairs) of L and R are provided for the line output terminal 62
and the line input terminal 63, but three or more lines may be provided.
By providing three or more systems, not only the one-dimensional ladder connection shown in
FIG. 2 (B) but also a complicated connection form in which branching is possible becomes
possible. When three or more pairs of line output terminals and line input terminals are
provided, audio signals input from all line input terminals other than the pair are supplied to
each line output terminal.
[0059]
The audio conference system of FIG. 6 has a plurality of audio conference devices 1A to 1D
linearly arranged in a large conference room 100 such as a large conference room. The plurality
04-05-2019
17
of audio conference devices 1A to 1D are formed to the same specifications, and have a long
shape. The audio conference devices 1A to 1D are arranged on the long desk 101 in a straight
line parallel to the longitudinal direction of the long desk 101.
[0060]
Each of the audio conference devices 1A to 1D takes charge of one conference attendee 200A to
200D. Each of the voice conference devices 1A to 1D detects the speech voice of the meeting
attendees 200A to 200D in charge, turns on / off sound collection, and performs an operation
not to respond to other voices.
[0061]
In the description of this embodiment, one voice conference apparatus is configured to handle
one conference attendee, but one voice conference apparatus may be arranged to handle a
plurality of conference attendees. Good. For example, in FIG. 6, the meeting attendees may be
further seated on the back side of the audio conference devices 1A to 1D so as to face the
meeting attendees 200A to 200D.
[0062]
A method of sound collection in this voice conference system will be described with reference to
FIG. In the following description, each audio conference device constituting the audio conference
system of FIG. 6 may be referred to as a “unit”.
[0063]
In the same figure (A), the sound emitted from the speaker array SPA wraps around and is input
to the microphone arrays MAF and MAR of the own device. Since the audio conference apparatus
is symmetrical in the front-rear direction, the sound that wraps around to the front microphone
array MAF and the sound that wraps around to the rear microphone array MAR have
substantially the same phase and level. Therefore, a symmetrical sound collection beam is formed
by the sound collection signal of the microphone array MAF and the sound collection signal of
04-05-2019
18
the microphone array MAR in the sound collection processing unit 17, and the difference is taken
to cancel out the sneak component from the speaker array SPA. Can be canceled. On the other
hand, since the meeting attendees are seated on the front side or the back side of the audio
conference device, the speech is biased either forward or backward. Therefore, even if the sound
collection beams before and after are differentiated as described above, the speech of the
meeting attendee remains at a high level in the difference signal.
[0064]
Note that in the arrangement of FIG. 6, the sound that has looped in from the speaker array of
another adjacent audio conference apparatus is also symmetrical in the front-rear direction, and
thus can be canceled by taking the difference similarly.
[0065]
The figure (B) is a figure explaining the function which makes it not sound-collect the speech
which the meeting attendee who is not in charge, ie, the meeting attendee of the adjacent area,
does not pick up.
Each voice conference device simultaneously forms a plurality of sound collection beams as in
the voice conference device 1B in the same figure, and among them, side beams 300L and R
which are sound collection beams directed to the left and right are beams for side talk detection
It is used as That is, even if the main beam 300C, which is an actual sound collection beam,
collects a high level sound signal, the level of the sound signal collected by the side beams 300L
and R is larger than this. The audio signal collected by the main beam 300C is not considered as
a target of sound collection, as it is a side speech sound from the side beam direction with a large
level. As a result, in the figure (B), even when the voice of the meeting attendee 200A that the
unit 1A is in charge is large and it gets around to the unit 1B at a high level, the signal level of
the collected sound of the side beam 300L is that of the main beam 300C. Since it becomes
larger than the signal level of the collected voice, it can be determined that the voice collected by
the main beam 300C is a side talk voice signal.
[0066]
In this manner, the main beam 300C picks up an audio signal of a certain level or more, and
outputs the audio signal to another device only when the level is higher than the level of the
collected sound signal of the side beams 300L and R. There is no misjudgment that the
microphones are turned on by collecting the wraparound sound from the adjacent area, such as
04-05-2019
19
the speech of the meeting attendee.
[0067]
Next, referring to FIG. 8, a unit arrangement for preventing howling due to howling paths formed
by a plurality of adjacent units will be described.
As shown in the unit 1A of the figure, each audio conference device forms the sound collection
beam 300 symmetrically on the front side and the rear side of the device. Although only the main
beam is illustrated in FIG. 8, the side beams are similarly formed symmetrically on the front side
and the back side. Further, as shown in a unit 1B of FIG. 6, each audio conference device forms a
sound emission beam 302 on the front and back sides of the device.
[0068]
The unit 1B emits the audio signal in the form of beam as described above, but the unit 1A
collects the audio signal in the form of beam as described above, but the audio signal emitted by
the unit 1B is the unit 1A. The sound is picked up slightly around the level. However, as shown in
FIG. 8, since both the sound collection beam 300 and the sound emission beam 302 are
symmetrical in the front-rear direction, the sound collection signal of the front side beam of the
unit 1A and the sound collection signal of the rear side beam are differenced. It is possible to
cancel the wraparound sound from the unit 1B by treating the signal as the sound pickup signal
of the beam.
[0069]
As a result, the feedback system of speaker array of unit 1B → microphone array of unit 1A →
line audio transmission from unit 1A to unit 1B can be cut off, and occurrence of howling can be
prevented in advance.
[0070]
FIG. 9 is a flowchart showing the signal processing operation of the sound collection control unit
17 of the audio signal processing device 1.
04-05-2019
20
First, the sound collection control unit 17 determines whether the level of the sound signal
collected by the main beam 300C has reached the speech volume (S1). If it has reached, the level
of the collected signal of the main beam 300C and the level of the collected signal of the side
beams 300L, R are compared, and the main beam 300C is higher than the level of the collected
signals of the side beams 300L, R It is determined whether or not (S2). If the level of the
collected sound signal of the main beam 300C is high, it is determined that the sound signal
collected by the main beam 300C is the speech sound signal of the meeting attendee in charge (Y
in S2), and the main beam 300C is collected. The sound signal produced is output to the
subsequent stage (the output of the sound signal is started).
[0071]
When the level of the audio signal collected by the main beam 300C does not reach the speech
volume (N at S1), the main beam is lower than the level of the collected signals of the side beams
300L and R (N at S2) The audio signal collected by the 300C is not output to the subsequent
stage (return to the process of S1).
[0072]
The sound collection control unit 17 determines whether the level of the sound signal collected
by the main beam 300C has reached the speech volume after outputting the sound signal to the
subsequent stage in S3 (S4).
If it has reached, the voice signal is continuously output to the subsequent stage (the process of
S4 is repeated). When it is determined that the time has not reached, the output of the audio
signal is stopped, and the process returns to the process of S1.
[0073]
After the sound signal collected by the main beam 300C is determined to be the speech sound
signal of the meeting attendant in charge by the above operation, unless the sound collection
level of the main beam 300C falls below the threshold value. As microphone on continues, even if
a large noise (for example, the next meeting attendee suddenly starts to be heard) occurs in the
adjacent area while the meeting attendee in charge is speaking, the noise (side sound pickup
signal) and The voiced speech (main sound pickup signal) is compared, and the microphone is
not turned off during the speech.
04-05-2019
21
[0074]
Next, FIG. 10 shows a teleconference in which a plurality of sets (two sets shown) of the audio
conference system 400 shown in FIG. 6 are provided, and the network communication control
apparatus 401 is connected to each and interconnected via the network 402. It is a block
diagram of a system.
[0075]
Even in an audio conference system 400 in which a plurality of audio conference devices that do
not incorporate an echo canceller are connected, the other party device installed remotely by
connecting a network communication control device 401 incorporating an echo canceller to the
front end on the network side. A call can be made without returning an echo to the other system.
The connection between the audio conference system 400 and the network communication
control device 401 is similar to the connection form of each unit in the audio conference system
400, with the audio signal output from the audio conference system 400 through the line output
terminal-line input terminal. This is a mode in which the signal is input to the network
communication control device 401 and the signal received by the network communication
control device 401 via the network is input to the audio conference system 400 via the line
output terminal and the line input terminal.
[0076]
The network communication control apparatus 401 communicates with the partner apparatus
via the network 402, and subtracts the component of the audio signal of the partner apparatus
sent from the partner apparatus from the component of the audio signal of its own apparatus to
be transmitted to the partner apparatus. This cancels the echo in which the audio signal of the
other device is fed back to the other device.
As described above, even in the case of an audio conference system configured with an audio
conference device that does not incorporate an echo canceller, by connecting a communication
control device provided with an echo canceller to the front end on the network side, a conference
system for teleconferencing is provided. It can be used.
04-05-2019
22
[0077]
By configuring the teleconference system in the connection form as shown in FIG. 10, it is
possible to connect large conference rooms and perform large scale teleconferencing.
[0078]
The figure which shows the structure and connection form of the conventional audio conference
apparatus The figure which shows schematic structure and connection form of the audio
conference apparatus which is embodiment of this invention The external perspective view of the
audio conference apparatus Bottom view and back and front side of the audio conference
apparatus Fig. 8 is a detailed block diagram of the same audio conference apparatus. Fig. 6
shows an audio conference system configured by connecting a plurality of audio conference
apparatuses. Fig. 7 illustrates a method of preventing howling in the audio conference system A
diagram for explaining the method A flowchart for explaining the procedure of sound collection
on / off of the voice conference apparatus A diagram showing the configuration of a
teleconference system in which the voice conference system is connected via a plurality of
networks
Explanation of sign
[0079]
1 (1A to 1D) audio conference device 100 (100A to 100D) audio conference device 200 (200A to
200D) conference attendee 300 (300C, L, R) sound collection beam 302 sound emission beam
04-05-2019
23
Документ
Категория
Без категории
Просмотров
0
Размер файла
37 Кб
Теги
jp2008294690
1/--страниц
Пожаловаться на содержимое документа