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JP2010203785

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DESCRIPTION JP2010203785
The present invention provides a sound source estimation method capable of accurately
estimating a sound source even in a place such as a vehicle interior where the influence of an
indoor mode is large. A sound / image collecting unit 10, in which a plurality of microphones M1
to M5 and a camera 12 are integrated, is moved slowly at a constant speed to generate a sound
around a place P at which abnormal noise is indicated. After the information of the image is
collected and the sound source direction (θ, φ) is calculated for each frequency using the sound
pressure signal of the sound collected by each of the microphones M1 to M5, the data (θ, φ) of
the sound source direction and the sound source The sound source position estimation screen
33k on which the graphic 32 indicating the estimated sound source direction is drawn is created
by combining the image data G of the captured image when used for the estimation of the
direction of the sound source, and this sound source position estimation The generation source
of the abnormal noise is specified as the direction of the generation source of the abnormal noise
where the graphic 32 in the screen 33k is drawn intensively. [Selected figure] Figure 1
Source estimation method
[0001]
The present invention relates to a method of estimating a sound source using information of
sounds collected by a plurality of microphones and information of a video taken by a
photographing means.
[0002]
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1
Conventionally, as a method of estimating the direction of arrival of sound, a microphone array in
which a large number of microphones are arranged at equal intervals is constructed, and the
direction of the sound source, which is the direction of arrival of sound waves, is estimated from
the phase difference of each microphone with respect to the reference microphone. A so-called
acoustic method has been devised (see, for example, Non-Patent Document 1).
On the other hand, rather than from the phase difference of the output signals of the plurality of
microphones arranged at the measurement point, a plurality of microphone pairs arranged in a
straight line crossing each other from the plurality of microphones constitute a pair of
microphones There has been proposed a method of estimating the direction of the sound source
from the ratio of the arrival time difference corresponding to the phase difference and the arrival
time difference between the other two microphones Mc and Md (for example, see Patent
Documents 1 to 3).
[0003]
Specifically, as shown in FIG. 8, two microphone pairs (M1, M3) and a microphone pair (four
microphones M1 to M4 are arranged at predetermined intervals on two straight lines orthogonal
to each other). M2 and M4) are arranged, and the arrival time difference of sound pressure
signals input to the microphones M1 and M3 constituting the microphone pair (M1 and M3), and
the microphones constituting the microphone pair (M2 and M4) The horizontal angle θ between
the measurement point and the position of the sound source is estimated from the ratio to the
arrival time difference of the sound pressure signal input to M2 and M4, and the fifth
microphone M5 is not on the plane made by the microphones M1 to M4. The four microphone
pairs (M5, M1), (M5, M2), (M5, M3), and (M5, M4) are further arranged in each position, and
From the arrival time difference between the microphones constituting the Kurofon pair, to
estimate the elevation angle φ formed between the position of the measurement point and the
sound source.
[0004]
As a result, the direction of the sound source can be accurately estimated with a smaller number
of microphones as compared to the case of estimating the sound source direction using the
microphone array.
Also, at this time, after capturing an image of the estimated sound source direction by providing
an image collecting means such as a CCD camera, the data of this image and the data of the
04-05-2019
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sound source direction are synthesized, and the sound source direction estimated in the image If
the sound pressure level and the sound pressure level are displayed graphically, the sound
source can be visually grasped.
[0005]
JP 2002-181913 A JP JP 2006-324895 A JP JP 2008-224259 A
[0006]
Jiro Oga, Yoshio Yamazaki, Yutaka Kanada; Acoustic System and Digital Processing,
Corona,1995
[0007]
By the way, in the above-mentioned conventional method, when the sound source is measured in
a room such as a vehicle cabin, depending on the position of the measurement point, the
influence of the indoor mode may be strong.
That is, since a large amount of reflected sound is generated indoors, resonance of the sound
generates a place where the sound pressure level is higher than that of the direct sound.
Therefore, when the influence of the indoor mode is strong, a figure indicating the estimated
sound source direction is drawn at various positions in the video, and it is difficult to specify the
position of the sound source. In the above-described conventional method, it is also conceivable
to perform measurement at a plurality of measurement points to specify the direction of the
sound source. That is, the direction of the sound source is specified by sequentially moving and
measuring the measurement point until an image drawn with a figure indicating the estimated
sound source direction concentrated on a specific part of the image is obtained with little
influence of the indoor mode. The source can be accurately estimated.
[0008]
However, in the above-mentioned conventional method, since the image of the sound source
direction is photographed after the sound source direction is estimated, the measurement time
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3
and the labor increase when the measurement is performed at a plurality of measurement points.
there were. In addition, when the measurement point is not appropriate, the work efficiency is
poor because it is necessary to change the measurement point again and perform measurement
again.
[0009]
The present invention has been made in view of the conventional problems, and it is desirable to
accurately identify the direction of the sound source and estimate the sound source with
certainty, even in a place such as a vehicle interior where the influence of the indoor mode is
large. It aims at providing the sound source estimation method which can be
[0010]
The invention according to claim 1 of the present application is a sound source estimation
method for estimating a sound source using information of sounds collected by a plurality of
microphones and information of an image photographed by a photographing means, A plurality
of steps of moving the sound / image collecting unit integrated with the photographing means,
and collecting the sound propagated from the direction estimated as the sound source and the
image of the direction estimated as the sound source; The second step of estimating the direction
of the sound source (horizontal angle θ and elevation angle φ) at a plurality of shooting
positions from the phase difference of the sound pressure signal of the sound collected by the
microphone, and the data of the estimated sound source direction And the image data of the
image captured when the sound used to estimate the direction of the sound source is sampled,
and the plurality of images are captured with a graphic representing the estimated direction of
the sound source. Create for each position And a fourth step of estimating a sound source from a
plurality of images in which the estimated direction of the sound source is drawn, and in the
fourth step, the direction of the estimated sound source is It is characterized in that the position
of the sound source is estimated on the assumption that the position where the figure is drawn
overlapping by a predetermined number or more in the video in which the figure shown is drawn
is the direction of the sound source.
[0011]
Note that in order to identify a portion in the video drawn by overlapping the figures indicating
the sound source direction, for example, for each of a plurality of pieces of image data Gk (k = 1
to n) of the continuously captured video, Each image data Gk is divided into m regions Rk (k = 1
to m), the density of points (θ, φ) in each region Rk is calculated, and a plurality of regions Rm
having the highest density are included. By extracting the image data Gk, it is possible to specify
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a portion drawn by overlapping a figure indicating the sound source direction.
Since the estimated position of the sound source exists in the region Rm where the density of the
image data Gk is the highest, for example, if the average value of the points (θ, φ) in the region
Rm is determined, the position of the sound source is accurately estimated can do.
[0012]
The invention according to claim 2 is the sound source estimation method according to claim 1,
wherein the direction determined as the direction of the sound source in the fourth step is a
direction estimated as the sound source in the first step. The sound source is estimated by
repeating the first step to the fourth step.
The invention according to claim 3 is characterized in that, in the sound source estimation
method according to claim 1 or claim 2, the sound / image collecting unit is moved in a space
intersecting with a floor surface or a ceiling surface. .
[0013]
The invention according to claim 4 is the sound source estimating method according to any one
of claims 1 to 3, wherein the plurality of microphones are arranged at predetermined intervals
on two straight lines intersecting each other. Microphones having first to fourth microphones
constituting the two pairs of microphone pairs and a fifth microphone not on the plane made by
the two pairs of microphones, the microphones constituting the two pairs of microphones Using
the ratio of the phase difference between the two microphones, and the phase difference
between the microphones constituting the four microphone pairs configured of the fifth
microphone and each of the four microphones configuring the two microphone pairs. And
estimating the direction of the sound source.
[0014]
According to the present invention, the sound / image collecting unit in which a plurality of
microphones and the photographing means are integrated is moved to generate sound
transmitted from the direction estimated as the sound source and the image of the direction
estimated as the sound source A plurality of images are drawn and a figure indicating the sound
source direction is drawn, a plurality of pictures are drawn, a picture in which the figure
indicating the sound source direction is concentrated is selected from the plurality of pictures,
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and the figure in the selected picture is concentrated. Since the position of the sound source is
estimated to be the direction of the sound source, the position of the sound source is accurately
estimated in a short measurement time even in a place such as a vehicle interior where the
influence of the indoor mode is large. can do.
[0015]
According to the method of the present invention, instead of capturing an image of the direction
of the sound source after estimating the sound source direction, while capturing information of
sound propagated from the direction estimated as the sound source, capturing the direction
estimated as the sound source Therefore, in the obtained multiple videos, the image center is not
the estimated sound source direction, but since the sound pressure signal of the sound and the
video signal are simultaneously and almost continuously measured, the sound source direction It
is possible to efficiently create a plurality of images in which a figure indicating.
[0016]
Also, since the sound source is estimated by repeating the first step to the fourth step, the figure
showing the estimated sound source direction is an image compared to the case where the
measurement point is simply moved and measured. It is possible to reliably obtain an image
drawn centered on a specific part of.
Therefore, the estimation accuracy of the sound source direction can be greatly improved.
In addition, by moving the sound / video sampling unit in a space crossing the floor or ceiling,
measurement is performed while changing the height of the sound / video sampling unit, and the
sound pressure level depends on the shape of the room. Since the influence of the distribution is
eliminated, the estimation accuracy of the sound source can be further improved.
[0017]
Further, first to fourth microphones constituting two pairs of microphones arranged at
predetermined intervals on two straight lines intersecting each other, and a fifth microphone not
on a plane formed by the two pairs of microphones, and To estimate the direction of the sound
source using the ratio of the phase difference between the microphones constituting the two
pairs of microphones and the phase difference between the first to fifth microphones. Therefore,
not only the horizontal angle θ but also the elevation angle φ can be estimated efficiently and
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accurately with a small number of microphones.
[0018]
The summary of the invention does not enumerate all necessary features of the present
invention, and a subcombination of these feature groups can also be an invention.
[0019]
It is a figure which shows the outline | summary of the sound source estimation method by this
invention.
It is a functional block diagram which shows the structure of the sound source position
estimation system used when estimating a sound source.
It is a flowchart which shows the method of estimating the generation source of noise.
It is a figure which shows an example of the moving method of an audio | voice / image | video
extraction unit. It is a figure which shows an example of the display screen on which the sound
source position estimation screen was displayed. It is a figure which shows the relationship
between the extraction position of a sound and an image, and a sound source position estimation
screen. It is a figure for demonstrating the method of remeasurement for sound source position
estimation. It is a figure which shows the arrangement of the microphone in the sound source
location method using the conventional microphone pair.
[0020]
Hereinafter, the present invention will be described in detail through the embodiments, but the
following embodiments do not limit the invention according to the claims, and all combinations
of the features described in the embodiments are not limited. It is not necessarily essential to the
solution of the invention.
[0021]
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7
Hereinafter, embodiments of the present invention will be described based on the drawings.
FIG. 1 is a view showing an outline of a sound source estimation method according to the present
invention. In this example, a generation source of abnormal noise generated in a passenger
compartment 51 of a passenger car 50 is estimated. Moreover, FIG. 2 is a functional block
diagram which shows a structure of the sound source position estimation system used for
estimation of a sound source. In each of the drawings, reference numeral 10 denotes an audio /
video sampling unit, and reference numeral 20 denotes a sound source position estimation
apparatus. The sound / image collecting unit 10 is an integrated unit of a plurality of
microphones M1 to M5 as sound collecting means and a CCD camera (hereinafter referred to as
a camera) 12 as an image collecting means. The sound collecting means 11 is constituted by the
microphones M1 to M5.
[0022]
The microphones M <b> 1 to M <b> 5 that constitute the sound collection unit 11 are fixed to the
microphone fixing unit 13 respectively. Also, the camera 12 is fixed to the camera support 14.
The microphone fixing portion 13 and the camera support 14 are connected by three columns
15 erected on the camera support 14. That is, the sound collection means 11 and the camera 12
are integrated. The microphones M1 to M5 are disposed above the camera 12. Among the three
columns 15, a handle 16 is provided on the column 15 positioned in the direction opposite to the
photographing direction of the camera 12. By holding the handle 16 and moving the camera
support 14, the sound collecting means 11 and the camera 12 can be moved integrally. The
microphones M1 to M5 measure the sound pressure level of the sound transmitted from the
sound source (not shown).
[0023]
The arrangement of the microphones M1 to M5 is the same as that shown in FIG. 8, and four
microphones M1 to M4 are arranged in two straight lines orthogonal to each other at two
predetermined intervals respectively. , M3) and a microphone pair (M2, M4), and the fifth
microphone M5 is not located on a plane formed by the microphones M1 to M4, specifically, a
square formed by the microphones M1 to M4. Place at the position of the apex of the
quadrangular pyramid whose base is. Thus, four microphone pairs (M5, M1) to (M5, M4) are
further configured. In this example, the photographing direction of the camera 12 is set to a
direction that makes approximately 45 ° with the two straight lines passing through the
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intersection of the two straight lines orthogonal to each other. Therefore, the direction of the
sound / image collecting unit 10 is the direction of the white arrow D in FIG. The camera 12
collects an image according to the direction of the sound / image collecting unit 10.
[0024]
The sound source position estimation apparatus 20 includes an amplifier 21, an A / D converter
22, an image input / output unit 23, a storage unit 24, a sound pressure signal extraction unit
25, a sound source direction estimation unit 26, and an image signal extraction unit 27 and data
synthesizing means 28 and sound source position displaying means 29. The amplifier 21
includes a low pass filter, removes high frequency noise components from the sound pressure
signal of each sound sampled by the microphones M1 to M5, amplifies each sound pressure
signal, and outputs the amplified signal to the A / D converter 22. The A / D converter 22 creates
sound pressure waveform data obtained by A / D converting each sound pressure signal, and
outputs this to the storage means 24. The video input / output means 23 inputs a video signal
continuously photographed by the camera 12 and outputs image data in the photographing
direction every predetermined time (for example, 1/30 seconds). The storage means 24 arranges
and stores sound pressure waveform data and image data in time series. As a method of
arranging and storing sound pressure waveform data and image data in time series, sound
pressure waveform data and image data may be synchronized and stored, or sound pressure
waveform data and image data may be separately stored. Well known methods can be used, such
as storing with time data attached.
[0025]
The sound pressure signal extraction means 25 extracts sound pressure waveform data from the
storage means 24 and outputs this to the sound source direction estimation means 26. At this
time, the sound pressure waveform data is taken out as sound pressure waveform data for each
predetermined time corresponding to the image data. The sound source direction estimating
means 26 obtains phase differences among the microphones M1 to M5 from the extracted sound
pressure waveform data, estimates the sound source direction from the obtained phase
differences, and outputs the estimation result to the data combining means 28. Do. Details of the
estimation of the sound source direction will be described later. The video signal extracting
means 27 extracts the image data for each predetermined time from the storage means 24 and
outputs the image data to the data combining means 28. The data synthesizing means 28 is data
of the sound source direction estimated by the sound source direction estimating means 26 and
the image data outputted from the video signal extracting means 27 (when the sound pressure
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signal of the sound used to estimate the direction of the sound source is sampled) Composite
with the captured image). The sound source position display means 29 displays a sound source
direction estimation image in which a figure indicating the direction of the sound source is drawn
in the image synthesized by the data synthesis means 28.
[0026]
Next, a method of estimating the generation source of the abnormal noise generated in the
compartment 51 of the passenger car 50 will be described with reference to the flowchart of FIG.
First, the sound / image collecting unit 10 and the sound source position estimating device 20
are brought into the compartment 51 of the passenger car 50, and the sound / image collecting
unit 10 and the sound source position estimating device 20 are connected. To prepare for
measurement (step S10). Then, as shown in FIG. 4, the sound / image collecting unit 10 is moved
slowly in the passenger compartment 51 at a constant speed, sound is collected by the
microphones M1 to M5, and images are collected by the camera 12 (Step S11). At this time, the
space in the passenger compartment 51 while directing the shooting direction D of the camera
12 indicated by the arrow in FIG. Move as you draw the figure of eight. The space S for moving
the sound / image collecting unit 10 is preferably moved in a plane intersecting the floor surface
or ceiling surface of the vehicle body 51. Moreover, as a standard of moving speed, 10 cm / sec.
It is preferable to set it as the following.
[0027]
Next, the sound pressure signal (analog signal) of the sound collected by each of the
microphones M1 to M5 is converted into a digital signal (sound pressure waveform data), which
is stored in the storage unit 24 and an image collected by the camera 12 The signal is also
converted into a digital signal, which is then stored in the storage means 24 (step S12). Then, the
sound pressure waveform data stored in the storage unit 24 is extracted, and estimation
calculation of the sound source direction is performed (step S13). The extraction of the sound
pressure waveform data is performed every predetermined time that is the same as the image
data in the imaging direction. Therefore, the estimation of the sound source direction can be
performed for each image data in the imaging direction stored every predetermined time. To
estimate the sound source direction, the sound pressure waveform data is frequency analyzed by
FFT, the phase difference between the microphones M1 to M5 is determined for each frequency,
and the direction of the sound source is determined for each frequency based on the determined
phase difference. presume. The method of calculating the horizontal angle θ and the elevation
angle φ in step S14 will be described later.
04-05-2019
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[0028]
Since the data of the estimated sound source direction is obtained for each image data, assuming
that the image number is k and the frequency is j, the data of the sound source direction can be
expressed as (θ kj, φ k j). As shown in FIG. 5, the data (θ kj, φ k j) of the direction of the sound
source and the image data Gk of the image photographed when the sound pressure signal of the
sound used for estimation of the direction of the sound source is sampled. The display screen
30k on which the sound source position estimation screen 33k on which the figure (in this case,
a circle of mesh pattern) 32 indicating the estimated direction of the sound source is drawn is
created for each image data Gk (step S14).
[0029]
On the display screen 30k, a sound source position where a mesh mark 32 indicating a direction
of a sound source is drawn on the k-th image 31k (image data Gk as image data) of the images
captured by the camera 12 An estimation screen 33k is displayed. The horizontal axis of the
sound source position estimation screen 33k is the horizontal angle θk, and the vertical axis is
the elevation angle φk. Further, the size of the circle 32 represents a sound pressure level which
is the size of the sound pressure signal. In addition, it is also possible to display the direction of
the estimated sound source for each preset frequency band. In this case, the color of the circle 32
may be set for each frequency band. Further, on the lower side of the sound source position
estimation screen 33, a sound pressure level display screen 34k displaying the sound pressure
level (dB) when the horizontal axis is θ is displayed. The sound pressure level display screen 34k
can also be displayed for each frequency band.
[0030]
In this example, a large number of sound source position estimation screens 33k created for each
of the image data Gk (k = 1 to n) are used to estimate the noise source. That is, from among the
multiple sound source position estimation screen 33k, an optimum estimation screen is selected
in which locations drawn by overlapping a predetermined number or more of mesh marks 32
drawn in the sound source position estimation screen 33k are selected. Step S15) A portion of
the optimum estimation screen on which the mesh marks 32 are concentrated is estimated to be
the direction of the noise source (step S16). In this example, although the sound source position
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display means 29 has the function of estimating the position of the generation source of the
abnormal sound, the optimum estimated screen selection means, which is a means for selecting
an optimal estimated screen separately, Sound source position specifying means for estimating
the position of the generation source may be provided. The measurer specifies the generation
source of abnormal noise and the position thereof with reference to the direction of the
estimated generation source of abnormal noise.
[0031]
There are the following methods as a selection method of the optimal estimation screen. First, as
shown in FIG. 6, for each of the plurality of pieces of image data Gk (k = 1 to n) of the
continuously photographed video, the space in the passenger compartment 51 is moved in a
manner of drawing a figure of eight. The image data Gk of the image captured and taken is
divided into m regions Rk (k = 1 to m), and the number of points (θ, φ) in each region Rk is
calculated, and this number is calculated. Of the image data Gk is set as the concentration
number n (k) of each image data Gk. A point (θ, φ) in each region Rk corresponds to a meshed
circle 32 in the image 31 k. For example, the region R4 has the largest number of points (θ, φ)
in the image data Gp of the image 31p photographed on the left side of FIG. 6 and the number is
four. Therefore, the concentration number n (p) of the image data Gp is four. On the other hand,
the region R5 has the largest number of points (θ, φ) in the image data Gq of the image 31q
photographed on the upper left side of FIG. 6, and the number is twelve. Therefore, the
concentration number n (q) of the image data Gq is 12. Thus, the optimal estimated screen can
be specified by calculating and comparing the concentration number n (k) of the plurality of
image data Gk. In this example, the image 31 q whose number of concentration n (q) of image
data G q is 12 is set as the optimum estimation screen.
[0032]
When estimating the sound source direction using the optimal estimation screen, the number of
divisions of the image data of the optimal estimation screen (here, the image data Gq) is
increased to estimate the direction of the noise source. Specifically, each image data Gk of a video
is divided into a number n of regions rk (k = 1 to n) larger than the m, and the number of points
(θ, φ) in each region rk is Respectively, the region rM having the largest number of points (θ,
φ) is determined. Then, if this region rM is set as the direction of the sound source, it is possible
to estimate the direction of the noise source with high accuracy. The average position of the
points (θ, φ) in the area Rm in which the number of points (θ, φ) is the largest in the image
data Gq of the optimum estimated screen may be determined, and this may be used as the
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direction of the sound source. In the image 31 q which is the optimal estimation screen, as shown
in FIG. 6, it is estimated that the generation source of the abnormal noise is in the region X
indicated by a black bold circle in the same drawing. Since there is a car stereo speaker in the
area X, it is presumed that the abnormal noise is caused by the driver turning on the car stereo
switch by mistake. On the other hand, in the image 31p which is not the optimum estimated
screen, the mesh pattern circle mark 32 is largely deviated from the region X even though the
car stereo speaker which is the generation source of abnormal noise is reflected. As described
above, when the image data to be the optimal estimation screen is specified from the plurality of
image data Gk and displayed as an image, and the sound source is estimated using this optimal
estimation screen, As described above, even in a place where the influence of the indoor mode is
large, the position of the sound source can be accurately estimated.
[0033]
As a method of selecting the optimum estimation screen, the sound source position estimation
screen 33k (k = 1 to n) is displayed on the display screen of the sound source position display
means 29 continuously in time series, and the measurer observes it as a moving image. It is the
easiest to judge. That is, when the measurer looks at the moving image, the moving image is
stopped when a screen appears continuously in which a portion where the circle mark 32 of the
mesh pattern drawn in the sound source position estimation screen 33k is concentrated appears.
Then, a plurality of sound source position estimation screens 33k before and after the time may
be sequentially displayed on the display screen of the sound source position display means 29,
and the optimum estimation screen may be specified.
[0034]
By the way, even if the optimal estimation screen is selected, the degree of concentration of the
mesh pattern circle marks 32 in the optimal estimation screen may be low. In this case, even if
the sound source direction is estimated using the optimal estimation screen, the accuracy is
expected to be low. Therefore, in the present example, assuming that the image data of the
optimum estimation screen is GM, the distribution width w of the point (θ, φ) in the region Rm
in this GM is determined and compared with the preset threshold wk. It is determined whether
the distribution width of the distribution is wide (step S17). When the width of the distribution is
wide, as shown in FIG. 7A, the region M presumed to have a noise source is also wide, so the
sound from the region M can be easily collected at the measurement point. It changes to the part
Q (step S18), returns to step S11, and performs re-measurement. Also at this time, the direction
of the sound / image collecting unit 10 is made to be the direction of the point Q where the
04-05-2019
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sound can be easily collected, and the sound / image collecting unit 10 is slowly moved and
measured at a constant speed. As a result, since it is possible to select the sound source position
estimation screen 33 having a higher degree of concentration of the figure 32 indicating the
direction of the estimated sound source, the sound source position estimation screen 33 is used
as an optimum estimation screen to identify the direction of the sound source. For example, the
source of the abnormal noise can be estimated more accurately. In addition, if the direction of the
sound source is estimated by repeatedly performing steps S11 to S18, the estimation accuracy of
the sound source direction can be improved, and the generation source of the abnormal sound
can be reliably estimated.
[0035]
The method of calculating the horizontal angle θ and the elevation angle φ in step S14 is as
follows. Assuming that the arrival time difference between the microphone Mi and the
microphone Mj of each microphone pair (Mi, Mj) is Dij, the horizontal angle θ and the elevation
angle φ, which are the sound incident directions, are given by the following equations (1) and (2)
Since the output signals of the microphones M1 to M5 are frequency-analyzed using FFT and the
arrival time difference Dij between the microphones Mi and Mj at the target frequency f is
calculated, the horizontal angle .theta. You can ask for That is, arrival of sound pressure signals
input to the microphones M1 and M3 constituting two microphone pairs (M1 and M3) and
microphone pairs (M2 and M4) arranged at predetermined intervals on two straight lines
orthogonal to each other. The horizontal angle θ between the measurement point and the sound
source position is estimated from the ratio of the time difference D13 and the arrival time
difference D24 of the sound pressure signal input to the microphones M2 and M4 constituting
the microphone pair (M2, M4), the arrival The elevation angle φ formed between the
measurement point and the sound source position is estimated from the time differences D13
and D24 and the arrival time differences D5j (j = 1 to 4) between the fifth microphone M5 and
the other microphones M1 to M4.
[0036]
The arrival time difference Dij is obtained by obtaining the cross spectrum Pij (f) of the signal
input to the two microphone pairs (Mi, Mj), and further using the phase angle information Ψ
(rad) of the target frequency f Is calculated using the following equation (3). The estimation
result of the sound source direction is performed for each of the image data in the shooting
direction stored at predetermined time intervals.
04-05-2019
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[0037]
As described above, in the present embodiment, the sound / image collecting unit 10 in which
the plurality of microphones M1 to M5 and the camera 12 are integrated is moved slowly at a
constant speed, and a place where noise generation is indicated The sound and image
information is collected centering on P, and the horizontal angle θ and elevation angle φ, which
are the direction of the sound source, are calculated for each frequency using the sound pressure
signal of the sound collected by each of the microphones M1 to M5. Direction data (θkj, φkj)
and the image data Gk of the image taken when the sound pressure signal of the sound used to
estimate the direction of the sound source is sampled, and the estimated sound source direction
is indicated The sound source position estimation screen 33k in which the graphic 32 is drawn is
created, and in this sound source position estimation screen 33k, the location where the graphic
32 indicating the direction of the sound source is drawn intensively is different as the direction
of the noise source. To identify the source of the sound Therefore, even in a place where the
influence of the indoor mode is large such as in the compartment 51 of the passenger car 50, the
generation source of abnormal noise and its position can be accurately estimated in a short
measurement time. In addition, when the degree of concentration of the figure 32 indicating the
direction of the sound source in the sound source position estimation screen is low, remeasurement is performed with the direction of the estimated noise source as the direction in
which abnormal noise is indicated. As a result, the noise source can be estimated more
accurately.
[0038]
In the above embodiment, the method of estimating the source of abnormal noise in the vehicle
compartment has been described, but the present invention is not limited to this, and it may be
used in places such as indoors where the influence of reflected sound from walls or the like is
large. It can be used to estimate the sound source. Further, in the above example, although the
predetermined time which is the imaging interval of the sound source position is 1/30 sec, it is
not limited thereto, and may be determined appropriately depending on the type of sound
source, the required measurement accuracy and the like. In addition, when moving the sound /
image collecting unit 10, it is not necessary to move the space in the cabin 51 so as to draw a
figure of eight, and a plane intersecting the floor surface or the ceiling surface of the vehicle
body 51 You can move it inside.
[0039]
04-05-2019
15
As mentioned above, although this invention was demonstrated using embodiment, the technical
scope of this invention is not limited to the range as described in the said embodiment. It is
obvious to those skilled in the art that various changes or modifications can be added to the
above embodiment. It is also apparent from the scope of the claims that the embodiments added
with such alterations or improvements can be included in the technical scope of the present
invention.
[0040]
As described above, according to the present invention, the sound source can be accurately
estimated even in a place such as a vehicle interior where the influence of the indoor mode is
large. Therefore, the generation source of abnormal noise and the like generated in the room is
specified. be able to. Therefore, soundproofing measures in the room can be performed
efficiently.
[0041]
DESCRIPTION OF SYMBOLS 10 sound / image collection unit, 11 sound collection means, 12
CCD camera, 13 microphone fixed part, 14 camera support stand, 15 post, 16 grip, M1 to M5
microphone, 20 sound source position estimation device, 21 amplifier, 22 A / D Converter, 23
image input / output means, 24 storage means, 25 sound pressure signal extraction means, 26
sound source direction estimation means, 27 image signal extraction means, 28 data synthesis
means, 29 sound source position display means, 30 display screen, 31 pictures, 32 figures
representing the direction of the sound source, 33 sound source position estimation screens, 34
sound pressure level display screens, 50 passenger cars, 51 cars.
04-05-2019
16
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