close

Вход

Забыли?

вход по аккаунту

JPH0564284

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH0564284
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
microphone device for adaptively controlling a sound collection form in a sound collection
environment.
[0002]
2. Description of the Related Art In order to pick up a sound with good quality, it is necessary to
pick up the sound according to the situation of a target sound source and ambient noise.
[0003]
When the microphones are roughly classified into nondirectional microphones and directional
microphones, the following characteristics are provided.
An omnidirectional microphone has uniform sound pressure sensitivity frequency characteristics
independent of the direction, distance and frequency of a sound source, and vibration sensitivity
frequency characteristics not dependent on frequency. On the other hand, the directional
microphone changes the sound pressure sensitivity not only by the direction of the sound source
but also by the distance. That is, when the distance between the sound source and the
microphone approaches, so-called proximity effect raises the sensitivity in the front direction and
the back direction in the bass range. In addition, its vibration characteristics also become high in
03-05-2019
1
the low frequency range. Furthermore, the sensitivity to the low frequency range is also
increased similarly to the wind.
[0004]
From the above, it is generally more advantageous for the microphone's directivity to be sharp in
a sound collection environment where ambient noise is not present. However, as the distance
between the sound source and the microphone approaches, it is necessary to correct the
proximity effect. Next, in a sound collection environment in which a noise source exists near the
microphone, for example, in a microphone for incorporating a video camera, there are noise
sources and vibration sources such as a drive system of a zoom lens and a tape traveling system.
Under such circumstances, and when the components of these noise sources are concentrated in
the low frequency range, omnidirectional microphones are more advantageous than directional
microphones. Conversely, when the components of the noise source are concentrated in the high
frequency range, the directional microphone is more advantageous than the nondirectional
microphone. However, when wind is present for outdoor use, a non-directional microphone is
advantageous at least in the low frequency range.
[0005]
Therefore, conventionally, the level of the output of the unidirectional microphone and the
output of the omnidirectional microphone are compared and determined, and when the output
level of the omnidirectional microphone is high, the output signal of the unidirectional
microphone is taken out and reversely In addition, when the output level of a unidirectional
microphone is high, it is possible to switch automatically so as to take out an output signal
combining the bass range of a nondirectional microphone and the middle to high range of a
unidirectional microphone. There is a microphone device. (Japanese Patent Application LaidOpen No. 1-39194)
[0006]
SUMMARY OF THE INVENTION However, in the above-described configuration, the sound
collection form is omnidirectional only in the entire range or unidirectional in the low range and
uni-directional in the middle and high range. Since there are only two forms in the case of sex,
there is a problem that the change in the form of sound collection before and after switching is
03-05-2019
2
large and unnatural. In addition, there is a problem that a stable output signal can not be
obtained because the sound collection form is frequently switched with a slight level fluctuation
near the threshold at which the sound collection form is switched. Furthermore, even if the noise
energy in the bass region becomes excessively large, the target sound is masked by the noise and
the intelligibility is lowered because the frequency characteristic is fixed, and the recording
device is connected to the microphone device. In this case, there is a problem that the automatic
gain control is activated to lower the gain and the desired sound can not be recorded sufficiently.
[0007]
The present invention solves the above-mentioned problems and is capable of controlling the
sound collection form in an aurally natural manner by adapting to changes in the sound
collection environment such as wind, vibration, and proximity sound, and performing stable and
good sound collection. It is an object to provide a microphone device.
[0008]
[Means for Solving the Problems] In order to achieve this object, a unidirectional microphone, an
omnidirectional microphone juxtaposed thereto, and a microphone connected to the
unidirectional microphone and outputting its bass range component 1, a high-pass filter
connected to a unidirectional microphone and outputting its treble component, and a second lowpass filter connected to a nondirectional microphone and outputting its bass component
Receiving the outputs of a filter, first, second and third level detectors respectively connected to a
first low pass filter, a high pass filter and a second low pass filter, and a three level detector The
difference α between the integral values of the outputs of the first and third level detectors at a
predetermined time and the ratio β of the integral values at a predetermined time of the outputs
of the first and second level detectors are determined. A preprocessing unit that creates a control
index to be evaluated as a set, a fuzzy inference unit that performs fuzzy inference upon
receiving an output from the preprocessing unit, a unidirectional microphone and a nondirectional based on the inference result of the fuzzy inference unit It has the composition
provided with the 1st and 2nd zone control part which controls the frequency zone with a sex
microphone, respectively, and the combiner which combines the output of the 1st and 2nd zone
control parts.
[0009]
[Operation] With this configuration, the presence or absence of the influence of wind, proximity
sound, vibration, etc. in a fixed time, the energy balance of the low range to its size and high
range are evaluated as a fuzzy set, and fuzzy control signals are obtained by fuzzy inference. This
fuzzy control signal makes it possible to control the frequency bands of the unidirectional
03-05-2019
3
microphone and the nondirectional microphone, respectively, and adapts to changes in the sound
collection environment such as wind, vibration, and proximity sound, and is audibly natural. The
form of sound collection can be controlled, and stable and good sound collection can be
performed.
[0010]
An embodiment of the present invention will be described below with reference to the drawings.
[0011]
FIG. 1 is a block diagram showing the configuration of a microphone device according to an
embodiment of the present invention.
In FIG. 1, 1 is a unidirectional microphone, 2 is a nondirectional microphone juxtaposed to the
unidirectional microphone 1, 3 is an output VU of the unidirectional microphone 1 and outputs
its bass component VUL. First high-pass filter 4 for receiving the output VU of the unidirectional
microphone 1 and outputting its high-range component VUH, and 5 for receiving the output VO
of the non-directional microphone 2 A second bass-pass filter for outputting the bass component
VOL, 6 is a first level detector for receiving the output VUL of the first bass-pass filter 3 and for
outputting its amplitude value EUL, 7 is a treble pass A second level detector that receives the
output VUH of the filter 4 and outputs its amplitude value EUH, and 8 is a third level detection
that receives the output VOL of the second low pass filter 5 and outputs its amplitude value EOL
9 is the above In response to the outputs EUL, EUH and EOL of the level detector, the difference
.alpha. Of the integral value in a fixed time between the output EUL of the first level detector 6
and the output EOL of the third level detector 8 is determined and the first A preprocessing unit
that determines a ratio β of integral values of the output EUL of the level detector 6 and the
output EUH of the second level detector 7 in a fixed time and generates a control index for
evaluating α and β as a fuzzy set, Reference numeral 10 denotes a fuzzy inference unit which
receives outputs α and β of the preprocessing unit 9 to perform fuzzy inference, 11 is
connected to the unidirectional microphone 1 and the fuzzy inference unit 10, and a single unit
based on the inference result of the fuzzy inference unit 10. A first band control unit for
controlling the frequency band of the output VU of the unidirectional microphone 1 and
outputting a signal VUM, 12 is connected to the nondirectional microphone 2 and the fuzzy
inference unit 10 and the inference result of the fuzzy inference unit 10 A second band control
unit that controls the frequency band of the output VO of the nondirectional microphone 2 based
on the above to output the signal VOM, 13 is an output VUM of the first band control unit 11
and an output of the second band control unit 12 A combiner 14 combines VOM and outputs a
03-05-2019
4
combined signal VT, and 14 is an output terminal of the combiner 13.
[0012]
The output signal VU of the unidirectional microphone 1 includes noise due to wind, proximity
noise, vibration and the like in addition to the signal due to the target sound.
Similarly, the output signal VO of the nondirectional microphone 2 also includes noise due to
wind, proximity noise, vibration and the like in addition to the signal due to the target sound.
Here, as described above, the unidirectional microphone 1 is more sensitive to the wind,
proximity noise, vibration, etc. than the nondirectional microphone 2, so if there is wind,
proximity noise, vibration, etc. The output signal VO of the directional microphone 2 appears
more prominently in the output signal VU of the unidirectional microphone 1.
That is, the presence or absence of wind, proximity noise, vibration, etc. can be determined by
comparing the level of the bass component of the output signal of both microphones. However,
the magnitudes of wind, proximity noise, vibration, etc. can not be determined by level
comparison of the bass component of the output signal of both microphones, so the bass
component and the treble component of the output signal VU of the unidirectional microphone 1
are Compare levels to judge.
[0013]
The level EUL of the bass component of the output signal VU of the unidirectional microphone 1
is determined via the first bass filter 3 and the first level detector 6. Similarly, the level EUH of
the treble-range component of the output signal VU of the unidirectional microphone 1 is
determined via the treble-pass filter 4 and the second level detector 7. The level EOL of the bass
component of the output signal VO of the nondirectional microphone 2 is determined via the
second bass filter 5 and the third level detector 8.
[0014]
The preprocessing unit 9 receives the signals EUL, EUH, and EOL from the level detectors, and
03-05-2019
5
calculates integral values E1, E2, and E3 for a fixed time (from t1 to t2) as shown in (Equation 1).
[0016]
Further, as shown in equation (2), the pre-processing unit 9 generates the integral value E1 of
the bass signal of the unidirectional microphone 1 at a given time and the bass value of the
omnidirectional microphone 2 at a given time. Find the ratio β of the difference α with the
integrated value E3 and the integrated value E1 of the low range signal of the unidirectional
microphone 1 at a fixed time and the integrated value E2 of the high range signal at a fixed time,
and make α and β fuzzy Create control indicators to evaluate as a set.
[0018]
The fuzzy inference unit 10 performs fuzzy inference in response to the outputs α and β of the
preprocessing unit 9.
The first band control unit 11 controls the frequency band of the output VU of the unidirectional
microphone 1 based on the inference result of the fuzzy inference unit 10 and outputs a signal
VUM.
Similarly, the second band control unit 12 controls the frequency band of the output VO of the
nondirectional microphone 2 based on the inference result of the fuzzy inference unit 10 and
outputs a signal VOM. The frequency bands of the first band control unit 11 and the second band
control unit 12 are shown in FIG. In FIG. 2, a is the gain frequency characteristic of the second
band control unit 12, that is, the sound collecting area of the nondirectional microphone, and b is
the gain frequency characteristic of the first band control unit 11, that is, the sound collecting
area of the unidirectional microphone. It represents. Further, fC is a crossover frequency of the
nondirectional microphone and the unidirectional microphone, and fL is a low cutoff frequency
of the nondirectional microphone.
[0019]
The combiner 13 combines the output VUM of the first band control unit 11 and the output VOM
of the second band control unit 12 and outputs a combined signal VT from the output terminal
14.
03-05-2019
6
[0020]
The membership function of the control index α related to the presence or absence of the
influence of wind, proximity sound, vibration, etc. is, for example, the one shown in FIG.
Here, P: influence of wind, proximity sound, vibration, etc. N: influence of wind, proximity sound,
vibration, etc. represents no effect. α 0 represents a threshold.
[0021]
Similarly, for example, the membership function of the control index β relating to the magnitude
of the effects of wind, proximity sound, vibration and the like and the energy balance of the low
range to the high range is used, for example, as shown in FIG. Here, PM: a little big PS: a little big
NS: a little little NM: a little little. β 0 represents a threshold.
[0022]
The fuzzy inference method of the fuzzy inference unit 10 performs the fuzzy operation
according to the control rule using the membership function of the condition unit, the
membership function of the conclusion unit, and the input value which are generally used, and
the synthetic fuzzy set is maximum The value is taken as the output synthesis function, and the
center of gravity of this output synthesis function is taken as the output of the fuzzy inference.
[0023]
The membership function concerning the crossover frequency fC between the nondirectional
microphone and the directional microphone in the conclusion part is, for example, the one shown
in FIG.
Here, PM: slightly high PS: slightly high NS: slightly low NM: slightly low.
[0024]
03-05-2019
7
Similarly, the membership function relating to the lower cutoff frequency f L of the
nondirectional microphone in the conclusion section is, for example, that shown in FIG. Here, PM:
slightly high PS: slightly high.
[0025]
A control rule for fuzzy inference using the above membership function may be, for example, as
shown in Table 1.
[0027]
As described above, according to the microphone device of the embodiment of the present
invention, the presence or absence of the influence of wind, proximity sound, vibration, etc. in a
fixed time, and the energy of the low frequency range with respect to its size and high range The
balance β is evaluated as a fuzzy set, and a fuzzy control signal is calculated by fuzzy inference,
and this fuzzy control signal enables control of the frequency bands of the unidirectional
microphone and the nondirectional microphone, respectively, wind, vibration, It is possible to
control the sound collection form in an aurally natural manner by adapting to changes in the
sound collection environment such as proximity sound, and perform stable and good sound
collection.
[0028]
As is apparent from the above embodiments, according to the present invention, the integral
value of the bass signal of a unidirectional microphone at a given time and the integral of the
bass signal of a nondirectional microphone at a given time Find the difference α from the value
and the ratio β of the integral value of the bass signal of the unidirectional microphone at a
given time and the integral value of the treble signal at a given time, and let α be the wind,
proximity sound, vibration, etc. Control signal relating to the presence or absence of influence, β
is a control index related to the size of the influence of wind, proximity sound, vibration, etc. and
the energy balance of the low range to the high range, α and β are evaluated as a fuzzy set,
Since the control signal is calculated and the frequency bands of the unidirectional microphone
and the nondirectional microphone are controlled respectively by this fuzzy control signal, wind,
vibration and proximity are obtained. Such as to adapt to changes in the sound collection
environment can control the sound collection form with aurally natural form, it can provide a
microphone apparatus which can stably and good sound pickup.
03-05-2019
8
1/--страниц
Пожаловаться на содержимое документа