JP3298297B2 - Voice direction sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound direction sensor for measuring the direction of arrival of a sound signal to be picked up.

[0002]

2. Description of the Related Art In a so-called stereophonic apparatus, sound signals picked up by, for example, two microphone units arranged at an arbitrary interval are uttered from speakers, respectively. It is known that a sound field is reproduced.

[0003] Therefore, a sound signal picked up by, for example, two microphone units arranged at an arbitrary interval as described above also includes information on the arrival direction of the picked-up sound signal. it is conceivable that. However, conventionally, means for measuring the direction of arrival using such collected sound signals has not been known.

[0004]

The problem to be solved is that there has hitherto not been known any means for measuring the direction of arrival using collected sound signals.

[0005]

A first means according to the present invention comprises a plurality of omnidirectional microphone units 1A and 1B arranged at a predetermined interval from each other, and sound collected by these microphone units. extracting means (bandpass filter 3A, 3B) for extracting an arbitrary spectrum of the audio signal in the signal, said plurality of microphones Uni
The audio signal picked up by one of the
Compare the delayed signal with the audio signal collected by another
The delay time is sequentially delayed by the unit delay time
Seeking Total time allowed, the measuring means (delay element 4 ₁ to 4 _k for measuring a time difference between each said audio signal, the calculator 5 ₀
To 5 _k, the detection circuit 7 ₀ to _7-k), comprising a calculating means (calculating unit 9) for measuring the direction of arrival of the arbitrary spectrum of the audio signal by calculating the measured time difference It is a voice direction sensor.

[0006]

A second means according to the present invention, in the sound direction sensor according to the first means, further comprises a delay means for delaying the predetermined interval by a time corresponding to a half of a propagation time of a sound wave. An audio direction sensor which compares an audio signal picked up by the microphone unit with a signal obtained by sequentially delaying the audio signal picked up by the one microphone unit by a unit delay time via the delay means. It is.

A third means according to the present invention, in the voice direction sensor according to the first means, further comprises comparing means for comparing signals at the input / output terminals of said extracting means, based on a comparison result from said comparing means. And a voice direction sensor in which the measuring means is controlled.

[0009]

[0010]

[0011]

According to this, an audio signal of an arbitrary spectrum is extracted from a signal picked up by a plurality of omnidirectional microphone units arranged at a predetermined interval from each other, and the extracted audio signal is extracted. Measures the time difference collected by each microphone unit and calculates the measured time difference, so that the direction in which the audio signal of an arbitrary spectrum arrives can be measured with a simple configuration.

Further, it is possible to control the directivity of an arbitrary microphone unit and the imaging direction of an arbitrary imaging device toward the direction in which the measured audio signal of an arbitrary spectrum comes.

[0013]

FIG. 1 shows a configuration in which a voice direction sensor according to the present invention is implemented using, for example, two microphone units.

In FIG. 1, reference numerals 1A and 1B denote omnidirectional microphone units. The audio signals collected by these microphone units 1A and 1B are passed through amplifiers 2A and 2B, respectively, to a band-pass filter (B
PF) 3A and 3B. Here, the band-pass filters 3A and 3B are for extracting an audio signal of interest, and the microphone units 1A and 1B
An arbitrary spectrum corresponding to the noticed audio signal in the signal picked up in step (1) is extracted. If you want to pay attention to the frequency of a human voice, for example, roughly 500-3000 Hz
Is suitable.

The signals passing through one of the bandpass filters 3A, 3B are k delay elements 4 ₁ , 4 ₂ ... Each having a unit delay time (τ).
_4k . The delay elements 4 ₁ , 4 ₂ ... 4 _k
The number (k) is such that the total delay time (kτ) is the time required for the audio signal to travel through the interval between the microphone units 1A and 1B. These delay elements 4
The signals at the input / output terminals of ₁ , 4, ₁ ... 4 _k are respectively k + 1 arithmetic units (Σ) 5 ₀ , 5 ₁ , 5 _2.
supplied to _k .

The signal passed through the other one of the band-pass filters 3A and 3B is applied to the delay elements 4 ₁ and 4 _2.
... Delay time corresponding to the center position of 4 _k (τk /
Calculator 5 through the delay unit 6 of 2) _0, 5 _1, 5 ₂ ...
・ Supplied to 5 _k . And these arithmetic units 5 ₀ ,
With 5 ₁ , 5 ₂ ... 5 _k , delay elements 4 ₁ , 4 _2.
k , the output signal of the delay means 6 is subtracted from the signal at each input / output end, and these subtracted signals are respectively detected by the detection circuits (D
ET) 7 ₀ , 7 ₁ , 7 ₂ ... 7 _k .

[0017] Thus the above calculator 5 _0, 5 _1, 5 ₂ ...
At 5 _k , the difference between the signal at the input / output terminal of each of the delay elements 4 ₁ , 4 ₂ ... 4 _{k and} the output signal of the delay means 6 is calculated. The output signal of this difference calculator 5 ₀ delay time of each input signal is equal as described later, 5 _1, 5 ₂ -
..Calculators 5 ₀ , 5 ₁ , 5 ₂ ... 5 as the level of the output signal of 5 _k decreases and the difference in delay time increases
The level of the output signal from _k is increased.

Further, a signal at the input / output terminal of the bandpass filter 3B is supplied to a detection circuit (DET) 8. Here, the detection circuit 8 determines whether or not the audio signals picked up by the microphone units 1A and 1B are the audio signals to be noticed. The determination is made based on the S / N, the duration of the signal, the result of comparison between the signal of interest and other signals, and the like.

The output signal of the detection circuit 8 is supplied to detection circuits 7 ₀ , 7 ₁ , 7 ₂ ... 7 _k , and the audio signals collected by the microphone units 1 A and 1 B are the audio signals of interest. in some case, the detection of the arithmetic unit _{5 0, 5 1, 5 2} ··· 5 k of the output signal according to the output signal of the detection circuit 8 is performed. As a result, the detection circuits 7 ₀ , 7 ₁ ,
In 7 ₂ ... 7 _k , the microphone units 1A, 1
The time difference (t) of the audio signal collected at B is measured.

That is, for example, a microphone unit
The time difference (t) between the audio signals collected in 1A and 1B is 0
Sometimes, the delay element 4 in the middle position_{k / 2}Output terminal signal
And the output signal of the delay means 6 having a delay time (τk / 2)
It becomes a new signal. Thereby, the arithmetic unit 5_{k / 2}Take out from
The level of the output signal of the difference is₀,
5 ₁, 5_Two... 5_kFrom the difference output signal
It is reduced in comparison.

When a time difference (t) occurs in the audio signals picked up by the microphone units 1A and 1B, the time difference (t) and the delay element 4 _{k / 2 at} an intermediate position
4 ₁ , 4 _2.
The arithmetic unit 5 in which the sum of the number of _k (± m) × the unit delay time (τ) is equal to the delay time (τk / 2) of the delay means 6
_{(k / 2) + -} level difference between the output signal taken out from _m is lower than the output signal of the difference is taken out from the other arithmetic unit _{5 0, 5 1, 5 2} ··· 5 k.

In this configuration, the delay time of the signal at the output terminal of the delay element 4 _{k / 2 at} the intermediate position is determined by the delay means 6.
Of the delay elements 4 ₁ , 4 ₂ ... 4 _{k which} are separated from each other back and forth around the delay element 4 _{k / 2} at the intermediate position described above (± m). ) × unit delay time (τ) is the microphone units 1A and 1B
Is equal to the time difference (t) of the audio signal picked up by.

[0023] Therefore, detection circuit 7 _0, 7 _1, 7 ₂ ... 7
Detection of _k is, for example, the calculator 5 _0, 5 _1, 5 _2, ... 5
A signal of "1" is taken out when the level of the output signal of _k is below a predetermined value, and a signal of "0" is taken out otherwise. The output signals of the detection circuits 7 ₀ , 7 ₁ , 7 ₂ ... 7 _k are supplied to the operation section 9, and the operation results are taken out to the output terminal 10.

Therefore, in the calculating section 9, the detecting circuits 7 ₀ , 7 ₁ , 7 ₂ ,.
_7k is discriminated, and the time difference (t = ± m) between sound signals picked up by the microphone units 1A and 1B from that position is determined.
τ) is measured. Next, the time difference (t) and the sound speed (A
[ M / sec]) to obtain the delay distance dd = At (1).

Further, from the delay distance d and the distance l between the microphone units 1A and 1B, θ = sin ^-1 (d / l) (2) is obtained, and the calculation result (θ) Is taken out to the output terminal 10.

That is, in FIG. 2, a sound source (not shown)
If the distance to the microphone units 1A and 1B is sufficiently longer than the distance l (predicted to be several centimeters) between the microphone units 1A and 1B, the arrival direction of the audio signal incident on each of the microphone units 1A and 1B Are substantially parallel as shown. Therefore, a line connecting the microphone units 1A and 1B is defined as an X-axis, a line perpendicular to the X-axis is defined as a Y-axis, and an angle (direction) at which a sound is incident on the Y-axis is defined as θ.

In this case, the microphone unit 1
The delay distance d obtained by multiplying the time difference (t) between the audio signals collected by A and 1B by the sound speed (A [ m / s]) is expressed as shown in the figure. From the delay distance d and the distance l between the microphone units 1A and 1B, θ is obtained by the above-described equation (2), so that the sound of interest with respect to the front (Y axis) of the microphone units 1A and 1B is obtained. The direction θ at which the signal arrives is determined.

Thus, according to the above-described apparatus, an audio signal of an arbitrary spectrum is extracted from the signals collected by the plurality of omnidirectional microphone units 1A and 1B arranged at a predetermined interval from each other (band). Pass filter 3
A, 3B), and the time difference at which the extracted audio signal is picked up by each microphone unit is measured (delay element 4 _1).
To 4 _k, computing unit 5 ₀ to 5 _k, the detection circuit 7 ₀ to _7-k), and
By calculating the measured time difference (calculating unit 9), the direction θ at which the audio signal of an arbitrary spectrum comes can be measured with a simple configuration.

In the above-described apparatus, the theoretical value of the measurement accuracy of the direction θ in which the audio signal arrives is expressed by the following equation (3). θ _min = sin ⁻¹ (Anτ / l) (3) where n = 1, 2,... k As is apparent from the equation (3), when it is desired to increase the measurement accuracy, the microphone unit 1A, Increase the distance l of the interval of 1B, or set the delay elements 4 ₁ , 4 ₂ ... 4 _k
May be shortened.

As is apparent from equation (3), when the direction θ at which the sound signal arrives is close to 0 degrees, the measurement accuracy is good, and as the direction approaches 90 degrees, the measurement accuracy decreases. For example, the distance l between the microphone units 1A and 1B is 10 cm, and the delay elements 4 ₁ , 4 _2.
When the unit delay time (τ) of _k is set to 21 μsec (48 kHz sampling), the delay elements 4 ₁ , 4 _2.
The number of 4 _k (k) is 14 and about 0 degree is about 4
And around 90 degrees, the direction θ at which the audio signal arrives can be detected with a measurement accuracy of about 15 degrees.

Further, when the voice direction sensor is implemented using the two microphone units 1A and 1B as described above, the range in which the direction θ at which the voice signal arrives can be measured in front of the microphone units 1A and 1B. Of 1
There is only a plane of 80 degrees. In this case, when an audio signal arrives from the rear of the microphone units 1A and 1B (the lower part in FIG. 2), the front and rear cannot be distinguished by the above-described configuration.

In this case, however, the above-described device causes the microphone units 1A and 1B, for example, to turn about the X-axis and Y-axis origins (microphone unit 1B) in FIG. By examining the transition of the output (terminal 10), it is possible to distinguish between front and rear. That is, for example, when the microphone unit 1 </ b> A turns backward and moves so that θ becomes a large value, it is determined that the audio signal has come from behind.

Alternatively, by using three microphone units 1a, 1b, and 1c, one of them is required, and the other two are arranged so that the lines connecting them intersect at right angles to each other. It is possible to measure the direction θ at which the audio signal arrives in all directions on the two-dimensional plane including the microphone units 1a, 1b, and 1c. In this case, the necessary microphone unit 1a and the other microphone units 1b and 1c
By equalizing the intervals between the two, it is possible to make the measurement accuracy of the above-described direction θ at which the audio signal arrives equal.

Further four microphone units 1
a, 1b, 1c, and 1d, for example, as shown in FIG.
By arranging c and 1d so as to be orthogonal to three dimensions, it is possible to measure the direction θ at which the audio signal arrives in all directions in the three-dimensional space. In this case as well, by equalizing the interval between the necessary microphone unit 1a and the other microphone units 1b, 1c and 1d, for example, the above-described direction in which the sound signal arrives θ
Measurement accuracy can be made equal.

In the apparatus described above, three to four micro-
When using the remote units 1a, 1b, 1c (1d)
Describes, for example, the essential microphone unit 1a
And one of the microphone units 1A and 1B of FIG.
And the subsequent microphone units 1b, 1c (1d)
As the other of the microphone units 1A and 1B,
1 is provided for each of the two or three sets of circuits shown in FIG. Was
However, the operation unit 9 is one, and all operation results are taken into consideration.
And each component θ in the direction in which the audio signal arrives_xθ_y(Θ _z)
Can be asked.

In the above-mentioned apparatus, for example, when sound signals are digitized to collect sound, the microphone units 1A, 1B (1a, 1b, 1c, 1
d) An A / D converter is provided at each subsequent stage, and the above-described processes are digitized, so that these processes can be performed more easily.

Further, in the above-described apparatus, the arrival direction θ of the measured audio signal is used, for example, as follows.

For example, the directivity of an arbitrary microphone unit can be controlled in the direction θ in which the measured audio signal arrives.

That is, when measuring the arrival direction θ of the audio signal, the microphone units 1A, 1B
(1a, 1b, 1c, 1d) are all omnidirectional, but after the measurement of the incoming direction θ of the audio signal is completed,
Arbitrary two or more of these microphone units are subjected to arithmetic processing or the like to have a single directivity, and the directivity is determined by an electrical or mechanical means using a direction θ in which the measured audio signal arrives. Can be controlled. The microphone units whose directivity is controlled include the above-described microphone units 1A and 1B (1a, 1b, 1).
c, 1d) may be provided separately.

Further, for example, the photographing direction of an arbitrary photographing device can be controlled in the direction θ in which the measured audio signal arrives.

That is, in FIG. 4, reference numeral 100 denotes a consumer-use VTR-integrated video camera, for example, a so-called 8-mm video camera as an arbitrary photographing device. Reference numeral 200 denotes a remote control device implemented as an accessory of the video camera 100. In the remote control device 200, the video camera 100 installed on the camera platform 201 above the remote control device 200 can be turned (panned) horizontally and turned (tilted) vertically by remote control. .

Therefore, in such a system, the video camera 100 is installed on the camera platform 201 of the remote control device 200 as shown in the figure, and a predetermined interval is provided in the vertical direction at the rear of the video camera 100, for example. Microphone units 101 and 102 are provided.

Then, these microphone units 1
With respect to the stereo microphones 01 and 102 and the stereo microphones 103 and 104 provided in, for example, the video camera 100, the audio signals collected by the microphones are supplied to the arithmetic unit 300, and the measurement of the arrival direction θ of the noted audio signal is performed. Done.

Further, an arbitrary remote control signal is formed by the arithmetic unit 300, and the remote control signal is transmitted to the cable 301.
Is supplied to the remote control device 200 through the controller, and the control is performed so that the shooting direction of the video camera 100 is directed to the direction θ at which the measured audio signal arrives.

Thus, according to the above-described apparatus, the arrival direction θ of the measured audio signal of an arbitrary spectrum is obtained.
, The directivity of an arbitrary microphone unit and the imaging direction of an arbitrary imaging device (video camera 100) can be controlled.

The above-described bandpass filters 3A, 3A
The extraction of the audio signal of interest in B and the determination of the audio signal of interest in the detection circuit 8 are performed not only by the above-described extraction using the band-pass filter having an arbitrary passband, but also by May be extracted and determined. Further, as the audio signal to be noticed, an arbitrary audio signal other than a human voice may be extracted and determined.

[0047]

According to the present invention, an audio signal of an arbitrary spectrum is extracted from a signal picked up by a plurality of omnidirectional microphone units arranged at a predetermined interval from each other, and the extracted audio signal is extracted. By measuring the time difference between the sound signals picked up by each microphone unit and calculating the measured time difference, it is possible to measure the direction in which the sound signal of an arbitrary spectrum arrives with a simple configuration. became.

Further, it is possible to control the directivity of an arbitrary microphone unit and the imaging direction of an arbitrary imaging device toward the direction in which the measured audio signal of an arbitrary spectrum arrives.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an example of a voice direction sensor according to the present invention.

FIG. 2 is a diagram for explaining this.

FIG. 3 is a diagram for explaining another example.

FIG. 4 is a configuration diagram of an example of an apparatus to which the present invention is applied.

[Explanation of symbols]

1A, 1B omnidirectional microphone units 2A, 2B amplifier 3A, a delay element 5 ₀ 3B bandpass filter _{(BPF) 4 1, 4 2} ··· 4 k unit delay time _{(τ), 5 1, 5} 2 · · · 5 _k calculator (sigma) 6 delaying means _{7 0, 7 1, 7 2} ··· 7 k, 8 detector (DET) 9 arithmetic unit 10 output terminal

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-262576 (JP, A) JP-A-4-198887 (JP, A) JP-A-3-42590 (JP, A) JP-A-5-205 323013 (JP, A) JP-A-1-263585 (JP, A) JP-A-60-33072 (JP, A) JP-A-62-182682 (JP, A) JP-A-63-124984 (JP, A) JP-A-3-195986 (JP, A) JP-A-64-73272 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S 3/80-3/86 G01S 5/18 -5/30 G01S 7/52-7/64 G01S 15/00-15/96 H04R 1/40 320 H04R 3/00 320

Claims (3)

(57) [Claims] 1. A plurality of omnidirectional microphone units arranged at a predetermined interval from each other, an extracting means for extracting an audio signal of an arbitrary spectrum in a signal collected by these microphone units, Sound collected by one of the microphone units
A signal obtained by sequentially delaying the voice signal by the unit delay time,
Compare the collected audio signal with
Calculate the sum of the times delayed sequentially by the unit delay time
A sound direction comprising: a measuring means for measuring a time difference between the sound signals; and a calculating means for calculating the measured time difference to measure the arrival direction of the sound signal of the arbitrary spectrum. Sensor. 2. The sound direction sensor according to claim 1 , further comprising delay means for delaying the predetermined interval by a time corresponding to a half of a propagation time of a sound wave, wherein the sound is picked up by the other microphone unit. An audio direction sensor configured to compare the audio signal with a signal obtained by sequentially delaying the audio signal collected by the one microphone unit by a unit delay time via the delay unit. 3. The voice direction sensor according to claim 1, further comprising comparison means for comparing signals at input and output terminals of said extraction means, wherein said measurement means is controlled based on a comparison result from said comparison means. Voice direction sensor.