JP2013090289

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DESCRIPTION JP2013090289
Abstract: The present invention provides an image display apparatus and a microphone
adjustment method for efficiently calculating adjustment values for respective frequencies at
which the phases of sound wave signals of a plurality of different frequencies coincide with each
other. An image display apparatus 1 comprising: a microphone group having a microphone M1
or the like for detecting a sound wave emitted by a sound source; and a sound source position
calculating means for calculating a sound source position based on a time difference between
sound waves reaching the microphone group. Test sound wave generating means 80, 85
arranged at positions equidistant from each microphone and emitting white noise containing
sound waves of different frequencies as sound waves, and test sound wave generation means
calculated by the sound source position calculation means Based on the position, the time
difference between sound waves of different frequencies reaching the microphone group is
calculated for each frequency, and the phase of the sound wave signal detected by the
microphone group is matched so as to make the time difference zero. And adjustment value
calculation means for calculating adjustment values collectively. [Selected figure] Figure 1
Image display device and method of adjusting microphone in image display device
[0001]
The present invention relates to an image display apparatus that displays an image for
identifying the position of a sound source in a display area of a display unit, and a method of
adjusting a microphone in the image display apparatus.
[0002]
In Patent Document 1, the applicant uses a plurality of (for example, five) microphones to
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estimate the position of a sound source based on the difference in arrival time of sound between
the microphones, and to capture an image of the estimated sound source position Disclosed a
technique relating to a sound source tracking system for displaying a sound source position on
an image near the sound source position sampled and displayed on a display.
[0003]
According to the present technology, for example, a sound source search system is installed at a
predetermined place in a factory or the like, and by periodically measuring the position of the
sound source, a failure sound is generated due to a device failure such as a transformer or a
motor. It can identify the sound source to emit.
This enables efficient detection of equipment abnormalities.
[0004]
JP 2003-111183 A
[0005]
In general, even in the same kind of microphones, the phase of each microphone may differ in
frequency.
Therefore, in the above-described sound source tracking system, in order to reduce the phase
difference of each frequency, test sound waves are generated in advance at positions equidistant
from a plurality of microphones before estimating the position of the sound source. The
adjustment value to match the phase of the sound wave signal of the sound wave detected by
each microphone was calculated so as to make the arrival time difference of the test sound wave
at 0 zero.
[0006]
However, it is necessary to calculate this adjustment value one by one each time the sound waves
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of each frequency are generated, after sequentially generating the sound waves of the desired
multiple frequencies as the test sound wave, There is a disadvantage that it takes time to
calculate all the adjustment values of.
In particular, when a test sound wave is generated including ultrasonic waves to calculate an
adjustment value for each frequency, the range of frequencies included in the test sound wave is
broadened. In such a case, when one adjustment value is calculated for each of a wide range of
frequencies included in the test sound wave, there is concern that it takes a long time to calculate
the adjustment value for every frequency.
[0007]
The present invention has been proposed in view of such a situation, and it is possible to
efficiently calculate adjustment values for each frequency at which the phases of sound wave
signals of a plurality of different frequencies detected by a plurality of microphones match. An
object of the present invention is to provide an image display device and a method of adjusting a
microphone in the image display device.
[0008]
An image display apparatus according to the invention of claim 1 comprises a display means for
displaying a captured image captured by a camera, and a microphone group having at least two
microphones arranged at predetermined intervals and detecting sound waves emitted by a sound
source. A sound source position calculating means for calculating the position of the sound
source based on the time difference when the sound wave reaches the microphone group, and an
image for identifying the position of the sound source is displayed in the captured image
displayed on the display means And an image display apparatus including display control means
for performing control, wherein the image display apparatus is disposed at a position equidistant
from the at least two microphones, and emits white noise including sound waves of different
frequencies as the sound waves. Based on the test sound wave generation means and the position
of the test sound wave generation means calculated by the sound source position calculation
means The phase of the signal of the sound waves of the plurality of different frequencies
detected by the microphone group so as to make the time difference zero by calculating the time
difference for the sound waves of the different frequencies to reach the microphone group for
each frequency And adjustment value calculation means for collectively calculating the
adjustment values for the respective frequencies for making the two match.
[0009]
The invention according to claim 2 is characterized in that, in claim 1, the microphone group is a
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first microphone group consisting of the two microphones disposed at predetermined intervals in
the horizontal direction, and a vertical direction intersecting the horizontal direction. And a
second microphone group consisting of the other two microphones disposed at a predetermined
distance from each other, and the propagation velocity of the sound wave detected by the first
microphone group and the second microphone group The test sound wave generation unit is
provided with correction temperature setting means for setting a correction temperature to be
corrected, with an intersection point of a straight line connecting the two microphones and a
straight line connecting the other two microphones as an origin The sound source position
calculating means at a position equidistant from each microphone on a straight line passing
through The horizontal direction from the origin to the test sound wave generation unit based on
the time difference between the sound waves of different frequencies reaching the first
microphone group and the correction temperature set by the correction temperature setting unit;
The angle is calculated, and the vertical angle from the origin to the test sound wave generating
means from the origin is calculated based on the time difference between the sound waves of
different frequencies reaching the second microphone group and the correction temperature.
Then, the position of the test sound wave generation means is calculated from the horizontal
angle and the vertical angle, and the adjustment value calculation means calculates the plurality
of different frequencies based on the horizontal angle calculated by the sound source position
calculation means. The time difference for the sound wave to reach the first microphone group is
calculated for each frequency, and the time difference is made zero. Calculating collectively the
first adjustment value for each frequency at which the phases of the signals of the sound waves
of the different frequencies detected by the microphone group are matched, and at the vertical
angle calculated by the sound source position calculating means Based on the time differences
between sound waves of different frequencies reaching the second microphone group are
calculated for each frequency, and the different detected by the second microphone group so as
to make the time difference zero. A second adjustment value for each frequency that causes the
phases of the sound wave signals of the plurality of frequencies to coincide with each other is
collectively calculated.
[0010]
According to the invention of claim 3, the adjustment value calculation means in claim 2
performs the first adjustment value for each frequency according to the equations (1) and (2)
According to 3), the second adjustment value for each frequency is collectively calculated.
P = ?D12 = ? (L / c О sin ?) (1) c = 334 + 0.6 t (2) Q = ?D34 = ? (L / c О sin ?) (3) P is the
first adjustment value, and Q is the second adjustment value.
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Also, D12 is a time difference in which the sound wave reaches the first microphone group, and
D34 is a time difference in which the sound wave reaches the second microphone group.
Furthermore, ? is the horizontal angle, and ? is the vertical angle. In addition, c is the
propagation velocity of the sound wave and t is the correction temperature. Furthermore, L is the
predetermined spacing of the two microphones in the horizontal direction and the predetermined
spacing of the other two microphones in the vertical direction.
[0011]
The invention according to claim 4 is characterized in that, in claim 1, the microphone group is a
first microphone group consisting of the two microphones arranged at a predetermined interval
in the horizontal direction, and in the vertical direction intersecting the horizontal direction. And
a second microphone group consisting of the other two microphones disposed at predetermined
intervals, and correcting the propagation velocity of the sound wave detected by the first
microphone group and the second microphone group The test sound wave generation unit with
the origin as the point of intersection between the straight line connecting the two microphones
and the straight line connecting the other two microphones. The sound source position
calculating means is disposed at a position equidistant from each microphone on a straight line
passing through the line. A horizontal angle from the origin to the test sound wave generation
unit in a polar coordinate system in which the distance from the origin is set to a half of the
predetermined interval based on the time difference between sound waves of different
frequencies reaching the first microphone group. Calculation, and the test sound wave generation
from the origin in the polar coordinate system based on the time difference between the sound
waves of different frequencies reaching the second microphone group and the correction
temperature set by the correction temperature setting means. The vertical angle to the means is
calculated, and the position of the test sound wave generation unit is calculated from the
horizontal angle and the vertical angle, and the adjustment value calculation unit calculates the
horizontal in the polar coordinate system calculated by the sound source position calculation
unit. The time difference between the sound waves of different frequencies reaching the first
microphone group is calculated for each frequency based on the angle. Calculating collectively a
first adjustment value for each frequency at which the phases of the sound wave signals of the
different frequencies detected by the first microphone group are matched so as to make the time
difference zero. At the same time, based on the vertical angle in the polar coordinate system
calculated by the sound source position calculating means, the time difference for the sound
waves of different frequencies to reach the second microphone group is calculated for each
frequency, A second adjustment value for each frequency at which the phases of the sound wave
signals of the different frequencies detected by the second microphone group are made to
coincide with each other so as to make the time difference zero is collectively calculated. Do.
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[0012]
In the invention of claim 5, according to claim 4, the adjustment value calculating means
calculates the first adjustment value for each frequency according to the equations (4) to (6), the
equation (5) and the equation (5) According to 6), the second adjustment value for each
frequency is collectively calculated.
R =-D12 =-(D34 x tan ?1) (4) S =-D34 =-([L / c x sin ?1] / {?1 + tan <2> ?1}) (5) c = 334 + 0 6t
(6) Note that P is the first adjustment value, and Q is the second adjustment value. Also, D12 is a
time difference in which the sound wave reaches the first microphone group, and D34 is a time
difference in which the sound wave reaches the second microphone group. Furthermore, ? is the
horizontal angle, and ? is the vertical angle. In addition, c is the propagation velocity of the
sound wave and t is the correction temperature. Furthermore, L is the predetermined spacing of
the two microphones in the horizontal direction and the predetermined spacing of the other two
microphones in the vertical direction.
[0013]
The invention according to claim 6 is any one of claims 1 to 5, wherein the at least two
microphones are ultrasonic microphones, and the predetermined interval is less than a half
wavelength of ultrasonic waves emitted by the sound source. The generation means is
characterized by emitting the white noise including the ultrasonic wave.
[0014]
In the method of adjusting the microphone in the image display device according to the invention
of claim 7, in the step of displaying the picked up image picked up by the camera on the display
means, the sound wave emitted by the sound source is arranged at a predetermined interval to
detect the sound wave Calculating a position of the sound source based on a time difference to
reach a microphone group having at least two microphones, and displaying an image identifying
the position of the sound source in the captured image displayed on the display means And
adjusting the microphones in the image display apparatus, the test sound wave generation means
emitting white noise including sound waves of different frequencies, and the test sound waves
are separated by an equal distance from the at least two microphones. Sound wave generation
step to generate the white noise from different positions The time difference between the sound
waves of different frequencies reaching the microphone group is calculated based on the position
calculating step of calculating the position of the test sound wave generating means and the
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position of the test sound wave generating means calculated in the position calculating step. The
adjustment value for each frequency is calculated at once, which is calculated for each frequency,
and the phases of the sound wave signals of the different frequencies detected by the
microphone group are matched so as to make the time difference zero. Prior to performing the
step of calculating the position of the sound source on the basis of the adjustment value
calculating step and the adjustment value calculated in the adjustment value calculating step, the
time difference for each of the plurality of different frequencies is previously made zero And
performing an adjusting step.
[0015]
According to the image display device of the invention of claim 1 and the method of adjusting the
microphone in the image display device of the invention of claim 7, sound waves of a plurality of
desired frequencies are generated one by one as test sound waves as in the prior art. Unlike
when the adjustment value for each frequency is calculated one by one, the adjustment value for
each frequency included in the white noise as the test sound wave is collectively calculated by
the adjustment value calculation means or the adjustment value calculation step. it can.
Therefore, adjustment values for each of a plurality of frequencies can be efficiently calculated.
According to the second aspect of the present invention, the adjustment value calculation means
calculates the adjustment value for each frequency included in the white noise as the test sound
wave in the horizontal direction in which the first microphone group is disposed (first adjustment
Value) and the adjustment value (second adjustment value) in the vertical direction in which the
second microphone group is arranged can be efficiently calculated. According to the invention of
claim 3 and claim 5, the adjustment value calculation means can easily calculate the first
adjustment value and the second adjustment value only by using a relatively simple calculation
formula. According to the invention of claim 4, the adjustment value calculation means calculates
the adjustment value for each frequency included in the white noise as the test sound wave based
on the horizontal angle from the origin in the polar coordinate system to the test sound wave
generation means. The adjustment value (first adjustment value) and the adjustment value
(second adjustment value) calculated based on the vertical angle from the origin in the polar
coordinate system to the test sound wave generation means can be efficiently derived. .
According to the invention of claim 6, by setting the arrangement interval of at least two
microphones to less than a half wavelength of the ultrasonic waves, it is possible to easily detect
the arrival direction of the ultrasonic waves emitted by the test sound wave generating means
facing the microphones. become.
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[0016]
It is a schematic block diagram of the image display apparatus of Embodiment 1 of this
invention. It is a schematic block diagram of a personal computer which constitutes the image
display device. It is a flowchart regarding the process which the same image display apparatus
performs. It is 1st explanatory drawing of adjustment value calculation processing which the
image display device performs. It is the 2nd explanatory view. A state in which an image is
displayed that identifies the arrangement position of the speaker that emits white noise on the
display after performing adjustment to match the phases of sound wave signals of multiple
frequencies included in the white noise detected by each microphone of the same image display
device FIG. It is a figure which shows the state which displayed the image which identifies the
arrangement | positioning position of the same speaker on the same display, before performing
adjustment which makes the phase of the signal of the sound wave of several frequencies
included in the same white noise correspond. FIG. 16 is a first explanatory diagram of adjustment
value calculation processing executed by the image display device of the second embodiment. It
is the 2nd explanatory view. It is the 3rd explanatory view.
[0017]
Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIGS. 1
to 6. The image display apparatus 1 according to the present embodiment includes a
measurement unit 10, an amplifier 20, a band pass filter 30, an A / D converter 40, a personal
computer 50, a video input / output unit 60, a display 70, and white. A noise generator 80 and a
speaker 85 are provided.
[0018]
As shown in FIG. 1, the measurement unit 10 includes support members 11 to 13, a base 16, a
CCD camera 17, a mounting and fixing base 18, a microphone support 19, and ultrasonic
microphones M 1 to M 4. Have. The base 16 is disposed on the upper portions of the support
members 11 to 13. The mounting and fixing base 18 is supported on the base 16 by a camera
support member. The CCD camera 17 is fixed to the camera support member in a state of being
directed forward. Ultrasonic microphones M1 to M4 are attached to the microphone support 19.
Here, the ultrasonic microphones M1 to M4 were omnidirectional. The microphone support 19 is
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fixed to the mounting and fixing base 18 with the ultrasonic microphones M1 to M4 directed
forward.
[0019]
In the measurement unit 10, as an example, ultrasonic microphones M1 and M2 having an outer
diameter of 5 mm are used. The horizontal distance between the two microphones M1 and M2 is
kept smaller than the half wavelength of the ultrasonic wave to be detected. Here, as an example,
the horizontal interval is 0.7 cm, and the half wavelength (about 0.8 cm) of a 22.5 kHz sound
wave is set. The horizontal interval is an example of a predetermined interval in the horizontal
direction of the present invention, and both microphones M1 and M2 are an example of a first
microphone group. The 22.5 kHz sound wave is an example of the ultrasonic wave of the present
invention.
[0020]
Furthermore, the outside diameter size of ultrasonic microphones M3 and M4 is the same as the
outside diameter size of both microphones M1 and M2. The two microphones M3 and M4 are
arranged at a vertical distance intersecting the horizontal line at a position that bisects the
horizontal line connecting the two microphones M1 and M2. The vertical distance was the same
as the horizontal distance (0.7 cm) described above. The vertical interval is an example of the
predetermined interval in the vertical direction of the present invention, and both microphones
M3 and M4 are an example of a second microphone group.
[0021]
Each of the microphones M1 to M4 is connected to the amplifier 20. The amplifier 20 amplifies
the sound wave signal transmitted from each of the microphones M1 to M4. The amplifier 20 is
connected to the band pass filter 30. The band pass filter 30 limits the band of frequencies
passing through the filter. The band pass filter 30 is connected to the A / D converter 40. The A /
D converter 40 converts the sound wave signal (analog signal) into a digital signal. The digital
signal is transmitted to the personal computer 50.
[0022]
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The CCD camera 17 is connected to the video input / output unit 60. The video input / output
unit 60 converts an imaging signal (analog signal) transmitted from the CCD camera 17 into a
digital signal. The digital signal (imaging signal) is transmitted to the personal computer 50 by
the video input / output unit 60. The personal computer 50 is connected to the display 70.
Reference numerals 71 and 72 in FIG. 1 denote display areas of the display 70. The display 70 is
an example of the display means of the present invention.
[0023]
The white noise generator 80 can generate white noise with uniform frequency characteristics as
the test sound wave. The white noise includes sound waves in the ultrasonic frequency range
(here, 22.5 kHz). The white noise generator 80 is connected to the speaker 85. The speakers 85
are disposed in front of the microphones M1 to M4. Further, the speaker 85 is at the origin
position O (see FIGS. 4 and 5). The microphones M1 to M4 are disposed equidistantly from the
microphones M1 to M4 on the straight line passing through. In this origin position O, the point at
which the horizontal line connecting the ultrasonic microphone M1 and the ultrasonic
microphone M2 is divided into two equal parts and the point at which the vertical line
connecting the ultrasonic microphone M3 and the ultrasonic microphone M4 is divided into two
parts overlap It is a position. The white noise generator 80 and the speaker 85 are an example of
the test sound wave generating means of the present invention.
[0024]
FIG. 2 is a schematic block diagram of the personal computer 50. As shown in FIG. The personal
computer 50 includes a keyboard 51, an arithmetic processing unit 52, and a storage unit 53.
[0025]
The keyboard 51 is connected to the arithmetic processing unit 52. The keyboard 51 includes
the number of ultrasonic microphones, the horizontal distance (0.7 cm in this case) between the
ultrasonic microphone M1 and the ultrasonic microphone M2, and the vertical distance (0.7 cm)
between the ultrasonic microphone M3 and the ultrasonic microphone M4. , And is used to input,
for example, a set value of a frequency for passing the band pass filter 30. In addition, in the
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present embodiment, the operator of the image display device 1 operates the keyboard 51 to
correct the propagation speed of the sound emitted from the sound source such as the speaker
85, etc. Adjustment intervals for matching the phase of the sound wave signal detected by each
of the microphones M1 to M4 are input. Here, the operator operates the keyboard 51 to
arbitrarily input the ambient temperature value (for example, 20 ░ C.) measured by the
thermometer, or the calculation interval of the horizontal angle ? and the vertical angle ? (for
example, 30 times / Seconds), calculation intervals (for example, 30 times / second) of first
adjustment values P and R, second adjustment values Q and S described later, and first
adjustment values P and R, second adjustment values Q and S I decided to enter. The keyboard
51 is an example of the correction temperature setting means of the present invention, and the
ambient temperature of the measurement unit 10 is an example of the correction temperature of
the present invention.
[0026]
The arithmetic processing unit 52 is connected to the storage unit 53 and the display 70
respectively. The storage unit 53 includes a digital signal processing program storage unit 54, a
display image data selection processing program storage unit 55, an image display control
program storage unit 56, and a data storage unit 57. The digital signal arithmetic processing
program storage unit 54 stores a program for executing test frequency analysis processing (S3),
adjustment value calculation processing (S4) and the like described later shown in FIG. The
display image data selection processing program storage unit 55 stores a program for executing
processing for selecting circular image data to be displayed in display areas 71 and 72 described
later. The image display control program storage unit 56 stores a program for executing
processing such as displaying various circular images in the display areas 71 and 72 based on
the image data.
[0027]
In the data storage unit 57, image data of a captured image of the CCD camera 17 displayed in
the display area 71 according to the captured signal from the CCD camera 17, test frequency
analysis processing (S3), adjustment value calculation processing (S4) Each data etc. which were
calculated by are stored. In addition, in the data storage unit 57, circular image data having
different colors and the same size is stored in association with the selected frequency extracted
by the test frequency analysis process (S3).
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[0028]
As described above, even when the same microphones M1 to M4 are used, the phases of the
respective microphones M1 to M4 may differ in frequency. Therefore, in the image display
device 1 of the present embodiment, white noise is generated using the white noise generator 80
and the speaker 85, and sound waves of a plurality of different frequencies included in the white
noise detected by the microphones M1 to M4. The adjustment value for each frequency that
makes the signal phase coincide can be calculated at once. Hereinafter, a process in which the
arithmetic processing unit 52 calculates the adjustment value will be described. Note that
generating white noise using the white noise generator 80 and the speaker 85 is an example of
the test sound wave generation step of the present invention.
[0029]
When the image display apparatus 1 is powered on, the arithmetic processing unit 52 performs
initial setting processing (S1), test signal acquisition processing (S2), test frequency analysis
processing (S3), and adjustment value calculation shown in FIG. 3. The processing (S4) is
executed respectively.
[0030]
In the initial setting process (S1), the number of ultrasonic microphones (four in this case) input
by the keyboard 51, the horizontal interval and the vertical interval (all 0.7 cm), and the
frequencies at which the band pass filter 30 is passed Setting value, ambient temperature value,
calculation interval of horizontal angle ? and vertical angle ? (30 times / second), calculation
interval of first adjustment values P and R and second adjustment values Q and S (30 times /
second) Lateral dimensions X1 and X2 of the display areas 71 and 72 (see FIGS. 6 and 7).
) And vertical dimensions Y1 and Y2 (see the same figure). A process of storing data relating to
the value etc.) in the data storage unit 57 is executed.
[0031]
The arithmetic processing unit 52 executes a test signal acquisition process (S2) after the initial
setting process (S1). In the test signal acquisition process (S2), a process of acquiring a white
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noise signal (sound pressure level) emitted from the speaker 85 is executed. Here, white noise
signals detected by the microphones M1 to M4 are input to the arithmetic processing unit 52 as
digital signals, as shown in FIG. Thereafter, the arithmetic processing unit 52 executes a process
of storing data corresponding to the white noise signal in the data storage unit 57.
[0032]
The arithmetic processing unit 52 executes a test frequency analysis process (S3) after the test
signal acquisition process (S2). In the test frequency analysis process (S3), the sound pressure
level of the white noise signal acquired by the test signal acquisition process (S2) is analyzed
using the program stored in the digital signal processing program storage unit 54, and the
selected frequency is selected. The processing of extracting a plurality of frequencies where the
sound pressure level exceeds a predetermined threshold level is executed. Thereafter, in the test
frequency analysis process (S3), a process of storing data of the selected frequency in the data
storage unit 57 is executed.
[0033]
The arithmetic processing unit 52 executes adjustment value calculation processing (S4) after the
test frequency analysis processing (S3). In the adjustment value calculation process (S4), the
phase of the signal of the sound wave of a plurality of selected frequencies detected by the
ultrasonic microphones M1 and M2 by the method described below using the program stored in
the digital signal arithmetic processing program storage unit 54 The adjustment values (the first
adjustment value P and the second adjustment value Q) for each of the selected frequencies are
calculated collectively. As an example, as shown in FIG. 4, the ultrasonic waves included in the
white noise have reached the ultrasonic microphone M2 earlier than the ultrasonic microphone
M1 due to the different phases of the ultrasonic microphones M1 and M2 for each frequency. In
this state, the phase of the signal of the ultrasonic wave detected by the ultrasonic microphone
M2 appears to lead the phase of the signal of the ultrasonic wave detected by the ultrasonic
microphone M1. The direction indicated by the double-dashed line arrow in FIG. 4 is the
propagation direction of white noise estimated from the phase difference of the ultrasonic signals
detected by the two ultrasonic microphones M1 and M2.
[0034]
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Actually, the speaker 85 is disposed on a straight line passing the origin position O orthogonal to
a straight line extending in the horizontal direction (left and right direction in FIG. 4) from the
origin position O. Although the horizontal angle ? to the arrangement position of the speaker 85
is zero, it is estimated that the speaker 85 is arranged in the direction inclined by a fixed
horizontal angle ? from the origin position O in the state shown in FIG. It will be In the
adjustment value calculation process (S4), the arithmetic processing unit 52 collectively
calculates horizontal angles ? for each of a plurality of selected frequencies using the following
equation (A) and equation (2). Data of the calculated horizontal angle ? is stored in the data
storage unit 57. The value of the horizontal angle ? is the horizontal distance L between the
ultrasonic microphone M1 and the ultrasonic microphone M2, the time difference D12 at which
the sound wave emitted from the speaker 85 reaches the two ultrasonic microphones M1 and
M2, the temperature of the sound wave propagation path It changes with t. Here, the data of the
ambient temperature of the measurement unit 10 stored in the data storage unit 57 is used as
the temperature t in the equation (2). C in following formula (A) and formula (2) is a propagation
velocity of a sound wave. The arithmetic processing unit 52 is an example of the sound source
position calculation means of the present invention, and the adjustment value calculation process
(S4) is an example of the position calculation step of the present invention. ? = sin <?1> {(D12
О c) / L} [░] (A) c = 334 + 0.6 t [m / s] (2)
[0035]
Subsequently, in the adjustment value calculation process (S4), the arithmetic processing unit 52
collectively calculates the time difference D12 for each of the plurality of selected frequencies
using the following equation (B) and the above equation (2). The data of the calculated time
difference D12 is stored in the data storage unit 57. Here, as the horizontal angle ? in the
equation (B), the data of the horizontal angle ? calculated by the arithmetic processing unit 52
using the above equations (A) and (2) and stored in the data storage unit 57 is Using. D12 = L / c
О sin ? (B)
[0036]
After that, the arithmetic processing unit 52 reads the data of the time difference D12 for each
selected frequency stored in the data storage unit 57 in the adjustment value calculation process
(S4), and then sets the time difference D12 to zero. 1) Using the above equation (2), the first
adjustment value P for each of the selected frequencies to be delayed is calculated collectively to
delay the phase of the sound wave signal detected by the ultrasonic microphone M2. As the first
adjustment value P, an average value of 30 adjustment values calculated in one second was
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adopted. The data of the calculated first adjustment value P is stored in the data storage unit 57.
The arithmetic processing unit 52 is an example of the adjustment value calculation means of the
present invention, and the adjustment value calculation process (S4) is an example of the
adjustment value calculation step of the present invention. P = ?D12 = ? (L / c О sin ?) (1)
[0037]
In addition, in the adjustment value calculation process (S4), the phases of the sound wave
signals detected by the ultrasonic microphones M3 and M4 are made to coincide by the method
described below using the program stored in the digital signal arithmetic processing program
storage unit 54. The second adjustment value Q for each selected frequency is calculated at once.
As an example, in FIG. 5, the ultrasonic waves reach the ultrasonic microphone M4 earlier than
the ultrasonic microphone M3 due to the different phases of the ultrasonic microphones M3 and
M4 for each frequency. The phase of the signal of the ultrasonic wave detected by the ultrasonic
microphone M4 appeared to lead the phase of the signal of the ultrasonic wave detected by the
ultrasonic microphone M3. Actually, the speaker 85 is at the origin position O (see FIGS. 4 and
5). 5 is perpendicular to the straight line extending in the vertical direction (vertical direction in
FIG. 5) through the origin point O, but in the state shown in FIG. It is estimated that the speaker
85 is disposed in a direction inclined by a predetermined vertical angle ? in the direction.
[0038]
In the adjustment value calculation process (S4), the arithmetic processing unit 52 collectively
calculates the vertical angles ? for each of a plurality of selected frequencies using the following
equation (C) and the above equation (2). Data of the calculated vertical angle ? is stored in the
data storage unit 57. D34 is the time difference for the sound waves to reach the two ultrasonic
microphones M3 and M4, and c is the propagation velocity of the sound waves. L is the vertical
distance between the ultrasonic microphone M3 and the ultrasonic microphone M4. ? = sin
<?1> {(D34 О c) / L} [░] (C)
[0039]
Subsequently, in the adjustment value calculation process (S4), the arithmetic processing unit 52
collectively calculates the time difference D34 for each of a plurality of selected frequencies
using the above equation (2) and the following equation (D). The data of the calculated time
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difference D34 is stored in the data storage unit 57. Here, as the vertical angle ? in the equation
(D), data of the vertical angle ? calculated by the arithmetic processing unit 52 using the
equations (C) and (2) and stored in the data storage unit 57 is used. . D34 = L / c О sin ? (D)
[0040]
After that, the arithmetic processing unit 52 reads the data of the time difference D34 for each
selected frequency stored in the data storage unit 57 in the adjustment value calculation process
(S4), and then sets the time difference D34 to zero. 3) Using the above equation (2), calculate
collectively the second adjustment value Q for each selected frequency to delay the phase of the
sound wave signal detected by the ultrasonic microphone M4. Similarly to the first adjustment
value P, the average value of 30 adjustment values was adopted as the second adjustment value
Q. The data of the calculated second adjustment value Q is stored in the data storage unit 57. Q =
-D34 =-(L / c x sin ?) (3)
[0041]
The arithmetic processing unit 52 determines whether the reset process has been performed
after the adjustment value calculation process (S4) (S5). Here, the operator operates the
keyboard 51 to determine whether or not a key instructing a reset operation has been pressed.
[0042]
When the arithmetic processing unit 52 determines that the key instructing the reset operation is
not pressed and the reset process is not performed in S5, the process returns to the test signal
acquisition process (S2). On the other hand, if the arithmetic processing unit 52 determines that
the reset process has been performed by pressing the key instructing the reset operation in S5,
whether or not to continue the execution of the program stored in each of the storage units 54 to
56 (S6).
[0043]
When the arithmetic processing unit 52 determines in S6 that the operator operates the
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keyboard 51 and selects to continue the execution of the program, the process returns to the
initial setting process (S1). On the other hand, when the arithmetic processing unit 52
determines in S6 that the operator operates the keyboard 51 and selects to cancel the execution
of the program, the above-described processes (S1 to S6) are ended.
[0044]
Next, processing of displaying an image for identifying the position of the speaker 85 that emits
white noise in each of the display areas 71 and 72 will be described. When the above-described
calculation process of the adjustment values P and Q is performed before the process of
displaying the image for identifying the position of the speaker 85 is started, the operator of the
image display device 1 operates the keyboard 51. Then, the data of each of the adjustment values
P and Q stored in the data storage unit 57 is transferred to the adjustment value detection
storage area of the data storage unit 57.
[0045]
The arithmetic processing unit 52 executes processing for acquiring a white noise signal emitted
from the speaker 85 and an imaging signal from the CCD camera 17. Here, the white noise signal
detected by each of the microphones M1 to M4 and the imaging signal are input to the
arithmetic processing unit 52 as digital signals as shown in FIG. Thereafter, the arithmetic
processing unit 52 executes a process of storing the data corresponding to the white noise signal
and the imaging signal in the data storage unit 57.
[0046]
The arithmetic processing unit 52 performs processing of extracting a plurality of frequencies as
the selected frequency and data of the selected frequency by the program stored in the digital
signal arithmetic processing program storage unit 54 as in the test frequency analysis processing
(S3) described above. The processing stored in the data storage unit 57 is executed.
[0047]
Thereafter, the arithmetic processing unit 52 executes a process of calculating the horizontal
angle ? for each of a plurality of selected frequencies by the program stored in the digital signal
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arithmetic processing program storage unit 54.
Here, first, the arithmetic processing unit 52 calculates the horizontal angle ?11 for each of a
plurality of selected frequencies using the same calculation formula as the above-mentioned
formulas (A) and (2). If the arithmetic processing unit 52 subsequently determines that the data
of the first adjustment value P is stored in the adjustment value detection storage area of the data
storage unit 57, the time difference D12 in the formula is Data of the first adjustment value P
stored in the adjustment value detection storage area is substituted to calculate the horizontal
angle ?12. Finally, the arithmetic processing unit 52 determines the result of adding the
horizontal angle ?11 and the horizontal angle ?12 as the horizontal angle ?. Since the
horizontal angle ?11 and the horizontal angle ?12 have the same value and different signs, the
determined horizontal angle ? is zero degrees. In this manner, in the image display device 1 of
the present embodiment, the adjustment to zero the time difference D12 in which the sound
waves of the plurality of selected frequencies reach the two ultrasonic microphones M1 and M2
is completed. In addition, performing adjustment which makes the time difference D12 zero is an
example of the adjustment step of this invention.
[0048]
In addition, the arithmetic processing unit 52 executes a process of calculating the vertical angle
? for each of a plurality of selected frequencies by the program stored in the digital signal
arithmetic processing program storage unit 54. Here, first, the calculation processing unit 52
calculates the vertical angle ?11 for each of a plurality of selected frequencies using the same
calculation formula as the above-mentioned Formula (C) and Formula (2). Subsequent to this,
when it is determined that the data of the second adjustment value Q is stored in the adjustment
value detection storage area, the calculation processing unit 52 stores the adjustment value
detection storage in the time difference D34 in the formula. Data of the second adjustment value
Q stored in the area is substituted to calculate the vertical angle ?12. Finally, the arithmetic
processing unit 52 determines the result of adding the vertical angle ?11 and the vertical angle
?12 as the vertical angle ?. The determined vertical angle ? is also zero degrees, as is the
horizontal angle ?. In this manner, in the image display device 1 of the present embodiment, the
adjustment to zero the time difference D34 at which the sound waves of the plurality of selected
frequencies reach the two ultrasonic microphones M3 and M4 is completed.
[0049]
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Subsequently, the arithmetic processing unit 52 executes a program stored in the image display
control program storage unit 56 to execute various circular images based on the circular image
data selected from the data storage unit 57 as described below. Z1 to Z4 (see FIG. 6). ) Is
displayed in each of the display areas 71 and 72.
[0050]
For example, when white noise is generated from the speaker 85, the arithmetic processing unit
52 generates four image data (here, color) corresponding to four selected frequencies (here, 4
kHz to 22 kHz) from the data storage unit 57. Reads out different circular image data). After that,
the arithmetic processing unit 52 rewrites the screen 30 times per second according to the
calculation interval (here, 30 times / second) of the horizontal angle ? and the vertical angle ?
based on the four read image data, and displays each Circular images Z1 to Z4 are displayed in
the areas 71 and 72, respectively. Since the horizontal angle ? calculated using the first
adjustment value P and the vertical angle ? calculated using the second adjustment value Q are
both zero degrees, as shown in FIG. The circular images Z1 to Z4 are superimposed and
displayed at a position where the horizontal angle ? is zero degree in the horizontal direction of
the area 71 and the vertical angle ? is zero degree in the vertical direction of the display area
71. As described above, in the image display device 1 according to the present embodiment, the
operator visually checks the circular image Z1 and the like displayed in the display area 71 to
visually identify the phase of the sound wave signal detected by each of the microphones M1 to
M4. It is possible to visually confirm that the adjustment to match has been made reliably. In
addition, the arithmetic processing unit 52 displays circular images Z1 to Z4 also at the
frequency display position corresponding to the value of the selected frequency in the vertical
direction of the display area 72. Although illustration is omitted, the arithmetic processing unit
52 transmits an image signal generated based on an imaging signal from the CCD camera 17 to
the display 70 to display a captured image in the display area 71. The arithmetic processing unit
52 is an example of the display control unit of the present invention.
[0051]
Assuming that the horizontal angle ? and the vertical angle ? are calculated with the phases of
the respective microphones M1 to M4 being different without using the adjustment values P and
Q, as described with reference to FIGS. 4 and 5. Although the horizontal angle ? and the vertical
angle ? are actually zero degrees, the arithmetic processing unit 52 calculates constant values
as the horizontal angle ? and the vertical angle ?. As a result, as shown in FIG. 7, for example,
as shown in FIG. 7, based on the calculated horizontal angle ? and vertical angle ?, a circular
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image is formed at a position different from the position where the speaker 85 is actually
arranged in the display area 71. Z1 to Z4 will be displayed.
[0052]
<Effects of First Embodiment> In the image display device 1 of the present embodiment, the
microphones M1 to M4 are used for each frequency each time a sound wave of a desired
frequency is generated one by one as a test sound wave as in the prior art. Unlike the case where
adjustment values for making the phases of detected sound wave signals coincide are calculated
one by one, the arithmetic processing unit 52 selects each selection frequency included in the
white noise as the test sound wave in the adjustment value calculation process (S4). Each
adjustment value (the first adjustment value P, the second adjustment value Q) can be calculated
at once. Therefore, adjustment values for each of a plurality of selected frequencies can be
efficiently calculated.
[0053]
In addition, in the adjustment value calculation process (S4), the arithmetic processing unit 52
sets the adjustment value for each selected frequency included in the white noise to the first
adjustment value P in the horizontal direction in which the two ultrasonic microphones M1 and
M2 are arranged. And the second adjustment value Q in the vertical direction in which the two
ultrasonic microphones M3 and M4 are disposed can be efficiently calculated.
[0054]
Furthermore, the arithmetic processing unit 52 can easily calculate the first adjustment value P
and the second adjustment value Q only by using relatively simple calculation formulas (1) to (3).
[0055]
In addition, by keeping the horizontal distance L between the two ultrasonic microphones M1
and M2 and the vertical distance L between the two ultrasonic microphones M3 and M4 smaller
than the half wavelength of the ultrasonic wave included in the white noise emitted by the
speaker 85, It becomes possible to make it easy to detect the arrival direction of the ultrasonic
waves emitted from the speaker 85 facing the four ultrasonic microphones M1 to M4.
[0056]
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Second Embodiment A second embodiment of the present invention will be described with
reference to FIGS. 8 to 10.
Here, the same components as in the first embodiment are denoted by the same reference
numerals, and the description thereof is omitted.
Image display apparatus 1A of the present embodiment (see FIG. 1).
In the initial setting process (S1) shown in FIG. 3, the arithmetic processing unit 52 calculates the
horizontal angle ?1 and the vertical angle ?1 calculation interval (for example, 30 times /
second) of the polar coordinate system described later input by the keyboard 51. A process of
storing, for example, data on an adjustment value R of 1 and a calculation interval (for example,
30 times / second) of the second adjustment value S in the data storage unit 57 is executed.
[0057]
Arithmetic processing unit 52 uses the program stored in digital signal arithmetic processing
program storage unit 54 in the adjustment value calculation process (S4) shown in FIG. 3 and
uses the program described below for each selected frequency according to the method
described below. A polar coordinate system (see FIG. 8) in which the distance is half (L / 2) of the
horizontal interval L and the vertical interval L (both are 0.7 cm). Horizontal angle ?1 (see FIGS.
8 and 9) from the origin position O to the arrangement position of the speaker 85 in FIG. Execute
a process to calculate) at once. The data of the horizontal angle ?1 is stored in the data storage
unit 57. As an example, in FIG. 8, the origin position O is obtained despite the fact that the
horizontal angle ?1 to the arrangement position of the speaker 85 is zero degree due to the
phase difference for each frequency of each of the microphones M1 to M4. The speaker 85 is
estimated to be disposed in a direction inclined by a predetermined horizontal angle ?1 from the
above.
[0058]
The horizontal angle ?1 is calculated using the following equation (F). D12 is a time difference
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between the sound waves included in the white noise emitted from the speaker 85 reaching the
two ultrasonic microphones M1 and M2, and D34 is a time difference between the sound waves
reaching the two ultrasonic microphones M3 and M4. It is. ?1 = tan <?1> (D12 / D34) [░] (F)
[0059]
Subsequently, in the adjustment value calculation process (S4), the arithmetic processing unit 52
uses the following equations (G) and (6) to obtain a polar coordinate system (see FIG. 8). Vertical
angle ?1 (see FIGS. 8 and 10) from the origin position O to the arrangement position of the
speaker 85 in FIG. Is calculated collectively over a plurality of selected frequencies, and
processing of storing data of the vertical angle .phi.1 in the data storage unit 57 is executed. In
the present embodiment, the spherical surface of the polar coordinate system shown in FIG. 8
has the same distance from the origin position O, so as shown in FIG. 10, the virtual microphone
M is disposed on the spherical surface for convenience. We thought that we could calculate.
Here, c is the propagation velocity of the sound wave, L is the horizontal interval and the vertical
interval, and t is the temperature of the propagation path of the sound wave. ?1 = sin <?1> {[?
(D12 <2> + D34 <2>)] О c / L} [░] (G) c = 334 + 0.6 t [m / s] (6) )
[0060]
After that, in the adjustment value calculation process (S4), the arithmetic processing unit 52
uses the above equation (6), the following equation (H), and the equation (I) to calculate the time
difference D12 and the time difference D34 for each of a plurality of selected frequencies.
Calculate at once. Data of the calculated time differences D12 and D34 are stored in the data
storage unit 57. Here, as the horizontal angle ?1 in the equation (H) and the equation (I), the
data of the horizontal angle ?1 calculated by the arithmetic processing unit 52 using the
equation (F) and stored in the data storage unit 57 is The data of the vertical angle ?1 calculated
by the arithmetic processing unit 52 using the equations (G) and (6) and stored in the data
storage unit 57 is used as the vertical angle ?1 in the equation (I). D12 = D34 О tan ?1 (H)
D34 = [L / c О sin ?1] / {?1 + tan <2> ?1} (I)
[0061]
Furthermore, in the adjustment value calculation process (S4), the arithmetic processing unit 52
reads out the data of each time difference D12 and D34 for each selected frequency stored in the
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data storage unit 57 and then makes each time difference D12 and D34 zero. In order to match
the phase of the sound wave signal detected by each of the microphones M1 to M4 using the
following formulas (4), (5), and the above formula (6), the first for each selected frequency The
adjustment value R and the second adjustment value S are calculated at once. As each adjustment
value R and S, the average value of 30 adjustment values calculated in 1 second was adopted.
The data of the calculated adjustment values R and S is stored in the data storage unit 57. R = D12 =-(D34 О tan ?1) (4) S = -D34 =-([L / c О sin ?1] / {?1 + tan <2> ?1}) (5)
[0062]
Also in the present embodiment, the arithmetic processing unit 52 can execute a process of
displaying an image for identifying the position of the speaker 85 that emits white noise in each
of the display areas 71 and 72. Before starting this process, the operator of the image display
device 1 operates the keyboard 51 to adjust the data of each adjustment value R, S stored in the
data storage unit 57 to the adjustment value of the data storage unit 57. Transfer to the
detection storage area.
[0063]
Thereafter, the arithmetic processing unit 52 executes processing for calculating the horizontal
angle ?1 and the vertical angle ?1 for each of a plurality of selected frequencies by the
program stored in the digital signal arithmetic processing program storage unit 54. Here, first,
the arithmetic processing unit 52 calculates the horizontal angle ?21 for each of a plurality of
selected frequencies using the same calculation formula as the above-mentioned formula (F),
each calculation similar to the above-mentioned formulas (G) and (6) The vertical angle ?21 for
each of the plurality of selected frequencies is calculated using the equation.
[0064]
Following this, when the arithmetic processing unit 52 determines that the data of the first
adjustment value R is stored in the adjustment value detection storage area of the data storage
unit 57, the time difference in the following equation (J) The first adjustment value R is
substituted for D12, and the second adjustment value S is substituted for the time difference D34
in equation (J) to calculate the horizontal angle ?22. When the arithmetic processing unit 52
determines that the data of the second adjustment value S is stored in the adjustment value
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detection storage area together with the calculation of the horizontal angle ?22, the equation (6)
is used, and The adjustment values R and S are substituted for the time differences D12 and D34
in the following equation (K) to calculate the vertical angle ?22. ?22 = ? {tan <?1> (D12 /
D34)} [░] (J) ?22 = ? (sin <?1> {[? (D12 <2> + D34 <2>))] О c / L}) [░] ... (K)
[0065]
Then, the arithmetic processing unit 52 determines the result of adding the horizontal angle
?21 and the horizontal angle ?22 as the horizontal angle ?1. Since the horizontal angle ?21
and the horizontal angle ?22 have the same value and different signs, the determined horizontal
angle ? is zero degrees. On the other hand, operation processing unit 52 determines the result
of adding vertical angle ?21 and vertical angle ?22 as vertical angle ?1. Similar to the
horizontal angle ?1, the vertical angle ?1 determined is also zero degrees. After that, as in the
first embodiment described with reference to FIG. 6, the arithmetic processing unit 52 has a
horizontal angle ?1 of zero degrees in the horizontal direction of the display area 71 and a
vertical angle ?1 of zero degrees in the vertical direction of the display area 71. It is possible to
overlap and display circular images Z1 to Z4 at the position.
[0066]
<Effects of Second Embodiment> In the image display device 1A of the present embodiment, the
arithmetic processing unit 52 sets the adjustment value for each selected frequency included in
the white noise in the adjustment value calculation process (S4) to the origin in the polar
coordinate system. The first adjustment value R calculated based on the horizontal angle ?1
from the position O to the arrangement position of the speaker 85 and the vertical angle ?1
from the origin position O in the polar coordinate system to the arrangement position of the
speaker 85 It can be divided efficiently into two adjustment values S.
[0067]
Further, the arithmetic processing unit 52 can easily calculate the first adjustment value R and
the second adjustment value S only by using relatively simple calculation formulas (4) to (6).
[0068]
The present invention is not limited to the embodiments described above, and part of the
configuration can be appropriately modified and implemented without departing from the scope
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of the invention.
For example, unlike the embodiment described above, the horizontal distance between the
ultrasonic microphone M1 and the ultrasonic microphone M2 and the vertical distance between
the ultrasonic microphone M3 and the ultrasonic microphone M4 are not limited to 0.7 cm, and
detection is performed. It may be changed to an appropriate value according to the frequency of
the ultrasonic wave to be attempted.
Furthermore, unlike the above-described embodiment, the image display apparatus is not limited
to the one provided with the four ultrasonic microphones M1 to M4, but, for example, one
provided with only the two ultrasonic microphones disposed apart from each other in the
horizontal direction. It may be provided with only two microphones arranged vertically apart
from one another.
[0069]
In the embodiment described above, an example in which the sound wave included in the white
noise is detected by the ultrasonic microphone has been described, but instead of the ultrasonic
microphone, a microphone capable of detecting a sound wave in a frequency range lower than
the ultrasonic frequency range is used. Sound waves included in white noise may be detected.
[0070]
In addition, in the above-described embodiment, an example has been described in which the
operator operates the keyboard 51 to transfer the adjustment values P to S to the adjustment
value detection storage area of the data storage unit 57. The unit 52 may automatically transfer
the adjustment values P to S to the adjustment value detection storage area after calculating the
adjustment values P to S.
Furthermore, in the first embodiment described above, an example of calculating each
adjustment value P, Q used to delay the phase of the sound wave signal detected by one
microphone than the phase of the sound wave signal detected by the other microphone is
described. As described above, instead of this, it is possible to calculate an adjustment value used
to advance the phase of the sound wave signal detected by one microphone over the phase of the
sound wave signal detected by the other microphone. In the first embodiment described above,
the adjustment values P to S are calculated in consideration of the temperature of the
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propagation path of the sound wave, but it is necessary to request high adjustment accuracy for
adjusting the phase difference of the sound wave signal If not, the adjustment value may be
calculated without considering the temperature of the propagation path.
[0071]
1, 1A и и и Image display device, 17 и и CCD camera, 51 и и и Keyboard и 52 и и и и и и и и и и и и и и и и и и и и и и и
ииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииии
и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и speaker Ultrasonic microphone, ? и и и Horizontal angle from
the origin position of the four ultrasonic microphones to the placement position of the speaker in
the horizontal direction, ? и и и Vertical angle from the origin position to the placement position
of the speaker in the vertical direction, ? 1 и и polar coordinates Horizontal angle from the origin
position in the system to the placement position of the speaker, ? 1 .. Vertical angle from the
origin position in the polar coordinate system to the placement position of the speaker.
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