close

Вход

Забыли?

вход по аккаунту

JP2014200064

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 JP2014200064
Abstract: To calculate an audio signal control value according to a change in noise environment
with a simple configuration. A noise signal extraction unit detects an audio signal and a broadcast
program signal detected from a microphone disposed at a distance from three or more
directional microphones and directional microphones having different directivity. Compare and
extract the noise detection signal. The noise source position calculation unit includes the
direction of the noise source specified based on the direction of directivity of the directional
microphone and the noise detection signal, the noise detection signal of the predetermined
directional microphone and the microphone, and the predetermined directional microphone The
position of the noise source is specified based on the position information of the microphone.
The noise source sound pressure calculation unit calculates the sound pressure level of noise in
the noise source from the noise detection signal and the position of the noise source. The control
value calculation unit controls a control value for controlling an audio signal output from the
speaker according to the sound pressure level of the noise at the speaker position calculated
from the position of the noise source, the sound pressure level of the noise, and the position
information of the speaker. calculate. [Selected figure] Figure 10
Audio output control device and audio output control method of broadcast system
[0001]
The present invention relates to an audio output control device and an audio output control
method of a broadcast system.
[0002]
A voice guidance system that provides voice guidance, music broadcasting, etc. to a specified
03-05-2019
1
area such as a station yard or a specified number of pedestrians in a predetermined range of
roads etc. automatically volume according to changes in noise environment A control system has
been proposed.
[0003]
For example, Patent Document 1 describes a device that detects the magnitude of noise with a
microphone installed in the vicinity of the speaker and controls the output sound volume of the
speaker according to the magnitude of the detected noise.
Further, in Patent Document 2, from the information such as the number of visitors in the
railway station yard, the installation status of microphones, presence / absence of trains, etc., the
attenuation amount of the sound pressure level which attenuates until the sound is transmitted
to the subject An apparatus for evaluating each frequency band and correcting an acoustic signal
to be output based on the evaluation result is described.
[0004]
JP-A-8-317497 JP-A-2011-193084
[0005]
The devices described in Patent Documents 1 and 2 require installation of the same number of
microphones as the area division to be controlled.
Furthermore, the device described in Patent Document 2 is complicated and requires a great deal
of cost to realize.
[0006]
An object of the present invention is to provide an audio output control device and an audio
output control method of a broadcast system capable of automatically controlling the volume and
the like in response to a change in noise environment with a simple configuration.
03-05-2019
2
[0007]
The present invention provides the following apparatus and method in order to solve the above
problems.
An audio signal detected from each directional microphone of a directional microphone unit
composed of three or more directional microphones (MIC 205 to MIC 207) having directivity in
mutually different directions and the directional microphone unit A noise signal extraction unit
(502) which compares an audio signal detected from a microphone (MIC 208) arranged at a
distance with a broadcast program signal and extracts noise detection signals of the directional
microphones and the microphones And identifying the direction of the noise source based on the
direction of directivity of each of the directional microphones and the noise detection signal, and,
among the directional microphones constituting the directional microphone unit, a
predetermined directional microphone Noise detection signal at the microphone, noise detection
signal at the microphone, position information of the predetermined directional microphone, and
A noise source position calculation unit (503) for identifying the position of the noise source
based on the position information of the ink and the identified direction of the noise source; at
least one of the three or more directional microphones and the microphone Noise source sound
pressure calculation unit (504) for calculating the sound pressure level of noise in the noise
source from the noise detection signal in one and the position of the identified noise source, the
position of the noise source identified, and The sound pressure level of the noise at the speaker
position is calculated from the sound pressure level of the noise at the noise source and the
position information of the speaker, and the sound pressure level at the speaker position is
calculated according to the sound pressure level of the noise at the speaker position. An audio
output control device for a broadcast system, comprising: a control value calculation unit (505)
for calculating a control value for controlling an audio signal to be output.
[0008]
An audio signal detected from each directional microphone of a directional microphone unit
composed of three or more directional microphones having directivity in mutually different
directions and the directional microphone unit are arranged separately Comparing the voice
signal detected from the microphone with the broadcast program signal and extracting the noise
detection signal in each of the directional microphones and the microphone; and the direction of
directivity of each of the directional microphones The direction of the noise source is specified
based on the noise detection signal, and among the directional microphones constituting the
directional microphone unit, a noise detection signal in a predetermined directional microphone,
a noise detection signal in the microphone, and the predetermined Position of the directional
microphone, position information of the microphone, and the position of the noise source based
03-05-2019
3
on the identified direction of the noise source Calculating the sound pressure level of the noise in
the noise source from the step of identifying the noise, the noise detection signal in at least one
of the three or more directional microphones and the microphone, and the position of the
identified noise source Calculating the sound pressure level of the noise at the speaker position
from the step of performing, the position of the identified noise source, the calculated sound
pressure level of the noise at the noise source, and the position information of the speaker
Calculating a control value for controlling an audio signal output from the speaker according to a
sound pressure level of noise at a position.
[0009]
According to the present invention, it is possible to provide an audio output control device and
an audio output control method of a broadcast system capable of automatically controlling the
volume and the like in response to a change in noise environment with a simple configuration.
[0010]
It is a figure which shows the example of arrangement ¦ positioning of the speaker of the
broadcast system which concerns on 1st Embodiment, and a block diagram for demonstrating
the structure of the broadcast system which concerns on 1st Embodiment.
It is a flowchart for demonstrating the flow of the process which concerns on 1st Embodiment.
It is a figure showing the position of a noise source in a 1st embodiment.
It is an example of a table which calculates ¦ requires the sound pressure level of the noise in
each speaker position from the sound pressure level of a noise source, and the distance from a
noise source to each speaker. It is an example of the table which calculates ¦ requires the
correction value of each speaker level from the sound pressure level of the noise in each speaker
position. It is an example of a table which calculates ¦ requires the correction value of a speaker
level directly from sound pressure level Sn of a noise source, and the distance from a noise
source to each speaker. It is a figure showing the position of a noise source in the modification of
a 1st embodiment. It is a figure which shows the example of arrangement ¦ positioning of the
speaker of the broadcast system which concerns on 2nd Embodiment, and a microphone. It is a
block diagram for demonstrating the structure of the broadcast system which concerns on 2nd
Embodiment. It is a figure for demonstrating the directivity of the microphone in 2nd
03-05-2019
4
Embodiment. It is a figure for demonstrating how to obtain ¦ require the direction of the noise
source in 2nd Embodiment.
[0011]
Hereinafter, an embodiment of a broadcast system according to the present invention will be
described with reference to the attached drawings.
[0012]
First Embodiment As shown in FIG. 1, the broadcast system 1 according to the present
embodiment includes a plurality of speakers (SP101 to SP112) installed in a station yard or a
ceiling of a wide hall, and three microphones (MICs 201 to 204). 203).
The number of speakers can be arbitrarily set according to the size of the installation place and
the application, but in the present embodiment, the number of speakers is twelve. The MICs 201
to 203 are noise detection microphones, which are spaced apart from each other by a
predetermined distance.
[0013]
The configuration of the broadcast system according to the present embodiment will be
described with reference to FIG. The MICs 201 to 203 detect speech and send the detected
speech signals to the AMPs 301 to 303, respectively. The AMPs 301 to 303 amplify audio
signals and send them to the ADs 401 to 403, respectively. The ADs 401 to 403 convert the
received audio signal into a digital signal, and send the digital signal to the arithmetic unit 500.
[0014]
Arithmetic unit 500 includes a central processing unit (CPU), a ROM storing programs and the
like, and a semiconductor circuit including a RAM as a work area, position information holding
unit 501, noise signal extraction unit 502, noise source position calculation unit It functions as
the noise source sound pressure calculation unit 504 and the control value calculation unit 505.
[0015]
03-05-2019
5
The positional information holding unit 501 stores positional information of each microphone
and speaker as three-dimensional coordinates.
For example, as shown in FIG. 1, the coordinates define X and Y coordinates with reference to an
arbitrary position of the ceiling, and the height direction is Z coordinate. In the present
embodiment, since the microphone and the speaker are all installed on the ceiling, the Z
coordinate is zero. For example, the coordinates of the MIC 203 are (18, 10, 0). The microphone
and the speaker do not have to be arranged on the ceiling, and the Z coordinate may not be zero.
The position information may be set and stored at the time of design or installation of the system.
[0016]
Arithmetic unit 500 calculates the position of the noise source and the sound pressure level of
the noise according to a procedure described later, and outputs a control signal for controlling an
audio signal output from each speaker based on the calculation result.
[0017]
The broadcast program transmission unit 600 branches and transmits broadcast program signals
such as music and voice guidance by the number corresponding to the number of speakers.
The broadcast program may be input from the outside of the system, or may be configured to
store the broadcast program in a storage medium connected or interpolated to the system. In the
present embodiment, since the number of speakers is 12, the broadcast program sending unit
600 branches to 12 and sends. The EVs 701 to 712 are electronic volumes, and the level of the
signal received from the broadcast program sending unit 600 is adjusted based on the control
signal received from the computing unit 500, and sent to the AMPs 801 to 512, respectively.
[0018]
The AMPs 801-812 amplify the received signals and send them to the speakers 101-112,
respectively. The speakers 101 to 112 output broadcast programs whose levels are adjusted. The
03-05-2019
6
broadcast program sent from the broadcast program sending unit 600 does not have to be one
type, and different programs may be broadcasted for each speaker, or BGM and the like may be
broadcasted overlappingly.
[0019]
Furthermore, the flow of processing will be described using the flowchart of FIG. In step S1, the
noise signal extraction unit 502 compares the detection signal of the microphones received from
the ADs 401 to 403 with the broadcast program signal received from the broadcast program
transmission unit 600, and transmits signals other than the broadcast program as noise signals
at each microphone. Extract as Since the positions of the speakers and the microphones are fixed,
the noise signal can be extracted by setting the detection level of the broadcast program detected
by each microphone in advance and subtracting it from the signal detected by each microphone.
Even when there are multiple types of broadcast programs, the broadcast program generated
from the present system is not detected as noise.
[0020]
In step S2, the noise source position calculation unit 503 specifies the position of the noise
source based on the noise signal detected by the noise signal detection unit 502. The time it
takes for the noise generated from the noise source to reach each microphone increases in
proportion to the distance from the noise source to the microphone. In the present embodiment,
since the microphones are installed at a predetermined distance from each other, the difference
in the distance from the noise source to each microphone can be calculated by comparing the
noise detection time of each microphone. . Also, from the difference in the distance from the
noise source to each microphone, it is possible to infer the position where the noise source may
exist.
[0021]
The noise detection time is compared with respect to two of the three microphones (microphone
A and microphone B) to estimate the position of the noise source. Assuming that the sound
velocity is 340 m / sec, the difference ΔL (m) in the distance from the noise source to each
microphone can be obtained by Equation (1) based on the noise detection time difference ΔT
(msec).
03-05-2019
7
[0022]
For example, assuming that the noise signal detection time of the microphone B is 7 msec slower
than the microphone A, the distance from the noise source to the microphone A is calculated to
be 2.38 m closer than the distance from the noise source to the microphone B from Eq. Ru. Fig. 4
shows that microphones A and B were installed at a distance of 5 meters, and the distance
between the noise source and microphone A was 2.38 m closer than the distance from the noise
source to microphone B. The positional relationship is illustrated on a plane. A and B indicate the
position of the microphone, and the dotted curve indicates the position where the noise source
may be present. Although in FIG. 4 the coordinates of the microphone A are represented by twodimensional coordinates with 0 being set for ease of understanding, in practice the position of
the noise source needs to be estimated in a three-dimensional space, and there is a noise source
The possible positions are indicated by curved surfaces in three-dimensional space. (Not shown.
)
[0023]
As described above, from the noise detection time difference between the two microphones
selected from the three microphones, the position where the noise source may be present can be
represented by a curved surface. The position of the noise source can be identified by obtaining
this curved surface for three combinations of MIC 201 and MIC 202, MIC 202 and MIC 203, and
MIC 203 and MIC 201, and finding the position corresponding to the intersection of the curved
surfaces obtained by each combination. .
[0024]
In step S3, the noise source sound pressure calculation unit 504 calculates the sound pressure
level of the noise source. An arbitrary one of the three microphones (for example, the
microphone with the largest noise detection level) is selected, and the distance between the
selected microphone and the noise source is calculated from the position information of the noise
source specified above. Assuming that the coordinates of the noise source are (Xo, Yo, Zo) and
the coordinates of the microphone A are (Xa, Ya, 0), the distance La from the noise source to the
microphone A can be obtained by Equation 2.
03-05-2019
8
[0025]
Since the sound pressure level of noise detected by the microphone is inversely proportional to
the square of the distance from the noise source to the microphone, the noise pressure level of
the noise detected by the selected microphone and the distance information to the noise source
Sound pressure level can be calculated. Here, the sound pressure level normalized at a position 1
m away from the noise source is defined as the sound pressure level of the noise source.
Assuming that the distance from the noise source to the microphone is La (m) and the sound
pressure level of noise at the microphone position is S (dB), the sound pressure level So (dB) of
the noise source can be obtained by Equation 3.
[0026]
The output level of each speaker is set in step S4 and subsequent steps. The number of speakers
is k, and serial numbers from 1 to k are assigned to each speaker. The order of serial number
assignment can be set arbitrarily. In step S4, a speaker is selected. In step S5, the sound pressure
level of noise assumed at the position of the selected speaker is calculated. Assuming that the
sound pressure level of the noise source is So (dB) and the distance from the noise source to the
n-th speaker is Ln, the sound pressure level Sn (dB) of the noise at the position of the n-th
speaker is calculated by be able to.
[0027]
In step S6, the control value calculation unit 505 calculates the correction value Gn (dB) for the
selected speaker using equation (5).
[0028]
That is, when the sound pressure level Sn of the noise at the speaker position is 65 dB or less, the
effect of the noise is not a concern, so the correction value of the speaker is set to 0 dB.
When the sound pressure level Sn of noise at the speaker position is greater than 65 dB and less
than or equal to 90 dB, the correction value of the speaker is set to be larger according to the
sound pressure level of noise. However, if the correction value of the speaker is larger than 25
03-05-2019
9
dB, the sound of the speaker itself becomes too loud and the person near the speaker feels
unpleasant, so the sound pressure level Sn of the noise at the position of the speaker is greater
than 90 dB Fixes the speaker correction value to 25 dB. The setting of the correction range and
the correction value is not limited to this, and may be set arbitrarily according to the
performance of the broadcasting system and the installation environment.
[0029]
The correction value Gn calculated by the control value calculation unit 505 is sent to the EVs
701 to 712 as correction data. In step S7, the EVs 701 to 712 correct the audio signal level to be
sent to the selected speaker. In step S8, it is determined whether n is equal to k. If n is not k, the
process proceeds to step S4. In step S4, n is made n = n + 1, and this is repeated until n = k. If it is
determined in step S8 that n = k, the process ends because the correction is completed for all the
speakers. The correction value once set is held and then leveled based on this correction value
until the correction value is calculated.
[0030]
The method of deriving the correction value is not limited to calculation processing, and a table
calculated in advance may be stored in the correction value calculation unit 505 and may be
calculated based on the table. An example of a table for obtaining the sound pressure level of
noise at each speaker position from the sound pressure level Sn of the noise source and the
distance from the noise source to each speaker is shown in FIG. For example, when the sound
pressure level Sn of the noise source is 62 dB or more and less than 64 dB, and the distance from
the noise source to the speaker position is 4.0 m or more and less than 4.8 m, the sound pressure
level of noise at the speaker position is calculated as 50 dB Be
[0031]
An example of a table for obtaining a correction value from the sound pressure level of noise at
each speaker position is shown in FIG. For example, when the sound pressure level of noise is 67
dB or more and less than 68 dB, the correction value Gn is +2 dB. Furthermore, as shown in FIG.
7 as an example, a table may be used in which the correction value is directly obtained from the
sound pressure level Sn of the noise source and the distance from the noise source to the
speaker. For example, when the sound pressure level of the noise source is 80 dB or more and
03-05-2019
10
less than 82 dB and the distance from the noise source to the speaker is 1.7 m or more and less
than 2 m, the correction value is 10 dB. The use of these tables can reduce the computational
load.
[0032]
The above control may be performed, for example, by giving the timer function to the calculation
unit 500 and performing it at predetermined time intervals set in advance. Further, it may be
performed when the noise detection level of any of the speakers changes by a predetermined
level or more.
[0033]
As described above, in the present embodiment, even when many speakers are installed, the
audio output of each speaker can be properly corrected only by installing three microphones.
[0034]
Modified Example In the above description, the noise source position calculation unit specifies
the position of the noise source by comparing the detection time difference of the noise signal
detected by each speaker.
However, when the noise is only the bass component, this method may not improve the accuracy
of specifying the noise source position.
[0035]
Since the magnitude of noise detected by each microphone is inversely proportional to the
square of the distance from the noise source to the microphone, the position of the noise source
can be identified by comparing the noise levels detected by each microphone. The noise
detection levels of two microphones (Mike A and Microphone B) among the three microphones
are compared to estimate the position of the noise source. Assuming that the distance from the
noise source to the microphone A is La and the distance from the noise source to the microphone
B is Lb, the ratio of La to Lb can be obtained by the equation (6) from the noise detection level
03-05-2019
11
difference ΔS (dB).
[0036]
In FIG. 8, assuming that the microphone A and the microphone B are installed 5 meters apart,
each microphone and the sound pressure level of the noise detected by the microphone B are 3
dB smaller than the sound pressure level of the noise detected by the microphone A The
positional relationship of the noise source is illustrated on a plane. A and B indicate the position
of the microphone, and the dotted curve indicates the position where the noise source may be
present. In practice, the position of the noise source needs to be estimated in three-dimensional
space, and the position where the noise source may exist is indicated by a curved surface in
three-dimensional space. (Not shown. )
[0037]
As described above, from the difference between the sound pressure levels of the noise detected
by the two microphones selected from the three microphones, it is possible to represent the
position where the noise source may exist as a curved surface. The position of the noise source
can be specified by obtaining this curved surface for three combinations of MIC 201 and MIC
202, MIC 202 and MIC 203, and MIC 203 and MIC 201, and finding the position corresponding
to the intersection.
[0038]
Although the method of specifying the position of the noise source by the detection time
difference of the noise signal in each microphone and the method of specifying the position of
the noise source by the detection level difference of the noise signal by each microphone may
work with either one, it is used in combination You may. For example, when the noise signal
contains high frequency components, it is determined by the detection time difference of each
microphone, and when the noise signal is only low frequency components, noise is detected more
accurately by using the detection signal level difference of each microphone. It becomes possible
to locate the source.
[0039]
03-05-2019
12
As described above, in the present embodiment, by detecting the noise signal with the three
microphones, the volume adjustment of the plurality of speakers can be appropriately performed.
[0040]
Second Embodiment In the present embodiment, the configuration for detecting the position of
the noise source is partially different from the first embodiment.
In the figure explaining this embodiment, the same number may be given to the part which is the
same as that of Embodiment 1, or similar, and explanation may be omitted. As shown in FIG. 9, in
this embodiment, directional microphones MIC205 to MIC207 and an omnidirectional
microphone MIC208 are arranged. The MICs 205 to MIC 207 are disposed at one place in a
direction in which the directivity directions of the respective microphones are different by 120
°, and the MIC 208 is disposed apart from it.
[0041]
As shown in FIG. 10, the broadcast system 2 according to the present embodiment has the same
configuration as the broadcast system 1 of the first embodiment except that the number of
microphone input systems is increased by one. MICs 205 to 207 indicate directional
microphones, and MIC 208 indicates a nondirectional microphone. The AMPs 305 to 308
amplify noise signals detected by the respective microphones. The ADs 405 to 408 convert noise
signals detected by the respective microphones into digital signals, and send the digital signals to
the calculation unit 500. The noise source position calculation unit 503 specifies the position of
the noise source based on the signals detected by the four microphones. Except for the above, it
is the same as FIG. 2 described in the first embodiment.
[0042]
FIG. 11 shows a diagram in which the directivity characteristics of the horizontal surfaces of the
three directional microphones are drawn in a circular shape (the amplitude axis is a linear scale).
The noise signal levels detected by the three directional microphones from the noise source at
specific times are proportional to the directional sensitivity of the horizontal plane angle of each
03-05-2019
13
microphone, so the noise signal levels detected by the three directional microphones The
direction of the noise source can be identified by comparing.
[0043]
The method of determining the direction of the noise source will be briefly described using FIG.
For example, the noise signal levels detected by the MIC 205 and the MIC 206 are compared,
and if the noise signal level of the MIC 206 is larger, it is understood that the direction of the
noise source is between 60 ° and 240 °. Similarly, if noise signal levels detected by the MIC
205 and MIC 207 are compared and the noise signal level of the MIC 205 is larger, the direction
of the noise source is between 300 ° and 0 °, or between 0 ° and 120 °. I understand that.
Together these two results show that the noise source is between 60 ° and 120 °, and the
magnitude of the difference is known, so that a specific angle can also be identified. In practice,
the direction may be specified by calculation from the noise signal detection level difference at
each microphone.
[0044]
If the direction of the noise source can be identified by the detection signal of MIC205 to
MIC207, the detection level of MIC208 placed apart from MIC205 to MIC207 should be
compared with the detection level of one of MIC205 to MIC207. Then, the distance from the
noise source to each microphone can be calculated. As a result, the position of the noise source
can be identified. The distance calculation method is the same as the contents described in the
first embodiment, so the description will be omitted.
[0045]
In the present embodiment, the directivity directions of the three directional microphones are
arranged in different directions by 120 °. However, the present invention is not limited to this,
as long as the directivity directions are substantially uniform and the angle of the directivity
direction is known. Further, in the present embodiment, the difference between the noise signal
detection levels of the two microphones is used to specify the distance from the noise source, but
as described in the first embodiment, the time difference between the waveforms is used or both
are used together. good.
03-05-2019
14
[0046]
In the present embodiment, the volume adjustment of the plurality of speakers can be properly
performed by detecting the noise signal with the three directional microphones and the one
nondirectional microphone. Moreover, since the installation place of a speaker can be made into
two places, compared with Embodiment 1, installation is easy.
[0047]
In the first and second embodiments, only the control of the volume of each speaker is
performed. However, the control of the sound quality may be performed, and the control of the
volume and the sound quality may be combined. For example, it is more effective to increase the
sound level output from the speaker as the noise increases and to emphasize the high frequency
component of the signal. In this case, the EVs 701 to 712 in FIGS. 2 and 10 may be replaced with
an equalizer that operates the frequency characteristics.
[0048]
In the second embodiment, an example in which the noise signal is detected by three directional
microphones and one nondirectional microphone is shown, but four directional microphones
may be used without using the nondirectional microphones. The microphone used in the first
embodiment may be a directional microphone or a nondirectional microphone, and a directional
microphone and a nondirectional microphone may be mixed.
[0049]
1, 2 broadcast system, 101 to 112 speaker, 201 to 203 microphone, 205 to 208 microphone,
500 operation unit, 501 position information holding unit, 502 noise signal extraction unit, 503
noise source position calculation unit, 504 noise source sound pressure calculation Unit 505
control value calculator 600 broadcast program transmitter 701-712 electronic volume
03-05-2019
15
1/--страниц
Пожаловаться на содержимое документа