JP3114376B2 - Microphone device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microphone device capable of collecting sound in accordance with an image by interlocking with a zooming mechanism such as a video camera or an 8 mm camera, and more particularly to a microphone device having a noise source or a vibration source therein. The present invention relates to a microphone device to be used.

[0002]

2. Description of the Related Art In recent years, in order to integrate video and sound for a video integrated camera or an 8 mm camera,
2. Description of the Related Art A microphone device capable of zooming and collecting sound in synchronization with video has been developed. These conventional microphone devices include two types, a monaural type and a stereo type.

The former monaural type microphone device changes the sound pickup angle of a microphone in accordance with the angle of view of a camera, and is based on a technique of changing a directivity pattern. This is realized by synthesizing the output of the microphone. In addition, in order to enhance the zoom effect, a method of increasing the sensitivity from wide angle to telephoto is generally adopted (for example, Japanese Patent Publication No. 59-101).
No. 19). To get an excellent zoom effect,
Consistency between the angle of view and the sound pickup angle is required. An example of the angle of view of the 10 × zoom lens is about 40 degrees at wide angle and about 4 degrees at telephoto. On the other hand, the sound pickup angle of the microphone is about 100 degrees at most even in the secondary sound pressure gradient type which is currently used as a sharp directivity, and is too wide as compared with the angle of view of the zoom lens. Therefore, there was no expected effect.

The latter stereo-type microphone device audibly corrects the drawbacks of the monaural-type microphone device, and produces a natural zoom effect by adding information on the movement and direction of the subject. . Ultra-directivity that changes the sound pickup angle of the left and right channels, the main axis of directivity, and sensitivity according to the angle of view of the camera, and mainly focuses on stereo sound pickup with a sense of realism at wide angle, and clear sound of the target sound source at telephoto Mainly sexual sound pickup.
This microphone device, like the monaural type microphone device, is usually realized by synthesizing the outputs of a plurality of directional microphones.
0-24636).

[0005]

However, since the above-mentioned conventional microphone devices use directional microphones such as unidirectional and bidirectional, a video integrated camera as described below is used. There was a problem to build it into such devices.

[0006] Microphones are roughly classified into omnidirectional microphones and directional microphones, and have the following characteristics. The omnidirectional microphone has a uniform sound pressure sensitivity frequency characteristic independent of the direction, distance, and frequency of the sound source, and a vibration sensitivity frequency characteristic without frequency dependence. On the other hand, the sound pressure sensitivity of a directional microphone changes depending not only on the direction of the sound source but also on the distance. That is, when the distance between the sound source and the microphone becomes shorter, the sensitivity in the front direction and the rear direction increases in the low frequency range due to a so-called proximity effect. Also, its vibration characteristics are increased in the low frequency range. Further, the sensitivity in the low frequency range is similarly increased with respect to wind.

As described above, first, in a sound collection environment in which no ambient noise exists, it is generally advantageous that the microphone has a sharp directivity. However, when the distance between the sound source and the microphone becomes short, 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 built-in microphone of a video integrated camera, there are noise sources and vibration sources such as a drive system of a zoom lens and a tape traveling system. In such an environment, and when the components of these noise sources are concentrated in the low frequency range, the omnidirectional microphone is more advantageous than the directional microphone. Conversely, when the components of the noise source are concentrated in the high frequency range, the directional microphone is more advantageous than the non-directional microphone. Next, when wind is present for outdoor use or the like, an omnidirectional microphone is more advantageous at least in the low frequency range.

[0008] As described above, when a built-in device such as a video-integrated camera that has a vibration source or a noise source and that is used outdoors is used, a conventional directional microphone is used as a component. The microphone device has a problem that the S / N ratio of the sound pickup is reduced and the sound pickup quality is deteriorated. In particular, an attempt to sharpen the directivity over the entire sound range in order to improve the zoom effect has, on the other hand, a problem of lowering the sound collection SN ratio.

In view of the above problems, the present invention not only enables stereo zoom sound pickup synchronized with video, but is also strong against noises such as vibration, proximity noise, and wind. It is an object of the present invention to provide a microphone device which can be built in a device such as a camera having a vibration source or a noise source therein, and which can reduce the size and weight of the whole device.

[0010]

In order to achieve this object, a microphone device according to the present invention comprises first and second omnidirectional microphones arranged in a straight line in the forward direction at an interval from each other. A third omnidirectional microphone arranged on a vertical bisector of a line connecting the first and second omnidirectional microphones, and a first and third omnidirectional microphone connected to the first omnidirectional microphone A phase shifter; second and third high-pass filters connected to the second omnidirectional microphone;
A first high-pass filter and a second phase shifter connected to the omni-directional microphone, a first subtractor for subtracting an output of the first phase shifter from an output of the first high-pass filter, A second subtractor for subtracting the output of the second phase shifter from the output of the second high-pass filter, and a third subtractor for subtracting the output of the third phase shifter from the output of the third high-pass filter. A first equalizer for equalizing the output of the first subtractor, a second equalizer for equalizing the output of the second subtractor, a third equalizer for equalizing the output of the third subtractor, A first variable amplifier for varying the output of the first equalizer, a second variable amplifier for varying the output of the second equalizer, a third variable amplifier for varying the output of the third equalizer, A first controller for controlling a second variable amplifier , A second controller for controlling the third variable amplifier, a first mixer for mixing the outputs of the first and third variable amplifiers, and a second controller for mixing the outputs of the second and third variable amplifiers. 2 is provided.

It is also effective that the three omnidirectional microphones are arranged so that their main axes are parallel and in the same direction, and are fixed so that the three omnidirectional microphones vibrate integrally.

[0012]

According to the present invention, not only the stereo zoom sound pickup synchronized with the image is possible but also the low range becomes omnidirectional and the middle and high range becomes directional by the above-mentioned structure.
It becomes strong against noise such as proximity noise and wind, and as a result,
It is possible to incorporate the device into a device having a vibration source or a noise source inside, such as a video integrated camera, so that the size and weight of the entire device can be reduced. Further, based on the stereo sound pickup, the directivity of the middle and high frequency ranges related to sound image localization can be freely set by the time constant of the phase shifter, so that effective zoom sound pickup is possible. Further, since a non-directional microphone is used, there is almost no variation in sensitivity, frequency characteristics, directivity characteristics, and the like unlike a directional microphone, and a low-cost and stable microphone device can be realized. Further, the omnidirectional microphone is not easily affected by diffraction or the like unlike the directional microphone, so that it can be easily attached to equipment. In addition, it is also possible to correct the influence of diffraction and the like by a circuit. Furthermore, if the main axes of the three omnidirectional microphones are arranged in parallel and in the same direction, and the three omnidirectional microphones are fixed so as to vibrate integrally, the omnidirectional It is more advantageous than sex.

[0013]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a microphone device according to one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a first omnidirectional microphone.
Lohon 2 is straight forward and spaced from it
The arranged second omnidirectional microphone, 3 is the first omnidirectional microphone.
Directional microphone 1 and second omnidirectional microphone 2
Third omnidirectional arranged on the vertical bisector of the line connecting
It is a sex mylok horn. Here is the center channel finger
The direction of the directional main axis is from the first omnidirectional microphone 1
In the direction toward the second omnidirectional microphone 2, the microphone
It is in the same direction as the directional principal axis of the lophone device. Also,
Leo's right channel directivity main axis orientation is first non-directional
Microphone 1 to third omnidirectional microphone 3
In the direction of
The direction of the directional main axis is from the third omnidirectional microphone 3
It is in a direction toward the second omnidirectional microphone 2. Ma
Directivity of the right channel from the main axis of the microphone device
Assuming that the angle seen from the main axis is φ, the orientation of the microphone device
The angle from the main axis to the directivity axis of the left channel is -φ
It is. d₁ Is the third omnidirectional microphone 3 and the first
Omnidirectional microphone 1 and second omnidirectional microphone
Is the distance from the phone 2 and d_Two Is the first omnidirectional micro
Distance between the microphone 1 and the second omnidirectional microphone 2
You. 4 is the output V of the third omnidirectional microphone 3_Three Receiving
The first high-pass filter that cuts the low frequency range
Output V of second omnidirectional microphone 2_Two Receiving bass
A second high-pass filter for cutting the area, 6 is a second non-pass filter
Output V of directional microphone 2_Two To cut the bass.
A third high-pass filter 7 is a first omni-directional filter.
Output V of Icrophone 1₁ Phase angle θ₁ The only transfer
1 is a phase shifter, 8 is the output of the third omnidirectional microphone 3
V _Three Phase angle θ_Two Second phase shifter, 9
The output V of one omnidirectional microphone 1₁ Phase shift angle
θ_Three Phase shifter 10 which shifts only the first high-pass filter.
First subtracting the output of the first phase shifter 7 from the output of the
, The subtractor 11 from the output of the second high-pass filter 5
A second subtractor 12 for subtracting the output of the second phase shifter 8;
From the output of the third high-pass filter 6 to the third phase shifter 9
A third subtractor 13 for subtracting the output is the first subtractor 10.
A first equalizer 14 for equalizing the output characteristics of
A second equalizer for equalizing the output characteristic of the second subtractor 11
The equalizer 15 equalizes the output characteristic of the third subtractor 12.
This is the third equalizer to be played. 16 is the first equalizer
A first variable amplifier for varying the output level of the
Reference numeral 7 denotes a second variable output level of the second equalizer 14.
The variable amplifier 18 has an output level 18 of the third equalizer 15.
The third variable amplifier 19 that varies the zoom signal has a wide zoom signal.
First and second variable increase in synchronization with the change from angle to telephoto
So that the output levels of the width devices 16 and 17 are continuously attenuated.
The first controller 20 controls the zoom signal from a wide angle.
The output of the third variable amplifier 18 is synchronized with the far change.
A second controller for controlling the level to increase continuously
21 is the output of the first and third variable amplifiers 16 and 18
A first mixer for mixing, 22 is a second and third variable amplifier
This is a second mixer that mixes the outputs of 17 and 18.

The operation of the microphone device configured as described above will be described below.

First, in the middle and high frequency range higher than the cutoff frequency (f _C1 ) of the first high-pass filter 4 and the second high-pass filter 5, the first and second variable amplifiers 16 and 1 are arranged.
The input signals V _R1 and V _L1 entering the direction 7 have directivities whose principal axes are the directions of angles φ and −φ from the directivity main axis of the microphone device, and the directivity pattern is as shown in FIG. In the middle and high frequency range higher than the cut-off frequency (f _C2 ) of the third high-pass filter 6, the input signal V _C1 entering the third variable amplifier 18 has directivity as the directivity main axis of the microphone device. The sex pattern is shown in FIG. Next, in a low frequency range lower than the cutoff frequency (f _C1 ), the input signal V _R1 becomes only the output V _{1 of the} first omnidirectional microphone 1, and the input signal V _L1 becomes the output of the third omnidirectional microphone 3. It becomes only the output V _3, V _R1, V _L1 both become non-directional. Similarly, in a low tone range lower than the cutoff frequency (f _C2 ), the input signal V _C1 becomes only the output V _{1 of the} first omnidirectional microphone 1 and becomes omnidirectional.

Also, the first and second variable amplifiers 16 and 17
The output levels V _R2 and V _L2 of the third variable amplifier 18 are controlled by the first controller 19 that has received the zoom signal, and the output level V _C2 of the third variable amplifier 18 is the second controller 20 that has received the zoom signal.
Is controlled _{by, V R2, V L 2,} V C2 is as shown in FIG. 5, a zoom signal in conjunction with the change from the wide angle to the telephoto, V _R2, V _L2 at the telephoto end continuously attenuated Minimum,
Conversely, V _C2 increases continuously and reaches a maximum at the telephoto end. Finally, the output signal V _R2 of the first variable amplifier 16 and the output signal V _C2 of the third variable amplifier 18 are mixed by the first mixer 21, and the output signal V _R becomes the right channel output, and The output signal V _L2 of the variable amplifier 17 and the output signal V _C2 of the third variable amplifier 18 are mixed by the second mixer 22,
The output signal V _L becomes the left channel output, and the directivity pattern of the output signals V _R and V _L of each channel interlocks with the change from the wide angle to the telephoto of the zoom signal, as shown in FIGS. Change to 4. In the figure, the solid line is the directivity pattern of the right channel, and the dotted line is the directivity pattern of the left channel. In this way, the camera signal is the wide-angle end, the output V _R of the right and left channels, the directivity of the main axis of the V _L phi, is open only -.phi, in conjunction with the camera signal changes to the telephoto, V _R, The directivity main axis of _VL also gradually changes in the direction of the directivity main axis of the microphone device, and at the telephoto end of the camera signal, the directivity main axes of V _R and V _L become the same and overlap with the directivity main axis of the microphone device, and stereo. Zoom sound pickup is possible.

As described above, according to the present embodiment, not only stereo zoom sound pickup synchronized with video is possible, but also the low range becomes omnidirectional and the middle and high range becomes directional.
It is resistant to noise such as vibration, proximity noise, and wind, and as a result, it can be built into devices that have internal vibration or noise sources, such as video-integrated cameras, and the overall size and weight of these devices are small and light. Is possible.

Further, the directivity of the middle and high frequency ranges relating to the sound image localization of the center channel and the stereo channels can be freely set by the time constant of the phase shifter, and the directivity of the right and left channels of the stereo relating to the spread of the stereo. Since the main axes (φ, −φ) can be freely set by the arrangement of the third omnidirectional microphone 3, effective zoom sound pickup is possible. In addition, since an omnidirectional microphone is used, sensitivity, frequency characteristics,
It is possible to realize a low-cost and stable microphone device with little variation in directional characteristics and the like.

Further, the omnidirectional microphone is not greatly affected by diffraction or the like unlike the directional microphone, so that it can be easily attached to equipment.

Further, it is also possible to correct the influence of diffraction or the like by a circuit. Also, as shown in FIG. 1, when the main axes of the three omnidirectional microphones are arranged in parallel and in the same direction, and fixed so that the three omnidirectional microphones vibrate integrally, the center channel and In the directivity region of the middle and high frequency range of the right and left channels, the attenuation of the sound pressure sensitivity in the 90-degree direction with respect to the 0-degree direction about the respective directivity main axes is more advantageous than the non-directionality with respect to vibration.

Although three phase shifters are used in this embodiment, a delay unit may be used instead of the phase shifter.

[0024]

As described above, according to the present invention, the first and second omnidirectional microphones and the first and second omnidirectional microphones are arranged in a straight line in the forward direction at an interval from each other. A third omnidirectional microphone disposed on a vertical bisector of a line connecting the first and second omnidirectional microphones, a first and third phase shifter connected to the first omnidirectional microphone, and a second omnidirectional microphone The second and third high-pass filters connected to the omnidirectional microphone, the first high-pass filter and the second phase shifter connected to the third omnidirectional microphone, and the output of the first high-pass filter The first for subtracting the output of the first phase shifter
, A second subtractor for subtracting the output of the second phase shifter from the output of the second high-pass filter, and subtracting the output of the third phase shifter from the output of the third high-pass filter A third subtractor, a first equalizer for equalizing the output of the first subtractor, a second equalizer for equalizing the output of the second subtractor, and equalizing the output of the third subtractor. A third equalizer, a first variable amplifier for varying the output of the first equalizer, a second variable amplifier for varying the output of the second equalizer, and a third variable amplifier for varying the output of the third equalizer. A variable amplifier, a first controller for controlling the first and second variable amplifiers, a second controller for controlling the third variable amplifier, and an output of the first and third variable amplifiers Mixing the outputs of the first mixer and the second and third variable amplifiers With a 2-mixer configuration, the low frequency range is omnidirectional and the mid-high frequency range is directional, so not only stereo zoom sound pickup synchronized with video is possible, but also vibration, proximity noise, wind, etc. Therefore, it can be built into a device having a vibration source or a noise source therein, such as a video integrated camera, and the entire device can be reduced in size and weight.

Furthermore, the three omnidirectional microphones are arranged so that their main axes are parallel and in the same direction, and are fixed so that the three omnidirectional microphones vibrate integrally. Become. As described above, the present invention has a great practical effect.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a microphone device according to an embodiment of the present invention.

FIG. 2 is a directivity pattern diagram at a wide-angle end of a zoom signal in the embodiment.

FIG. 3 is a directional pattern diagram of a zoom signal at an intermediate position between a wide angle and a telephoto position in the embodiment.

FIG. 4 is a directivity pattern diagram at a telephoto end of a zoom signal in the embodiment.

FIG. 5 is a change characteristic diagram of an output level of the variable amplifier in the embodiment.

[Description of Signs] 1 First omnidirectional microphone 2 Second omnidirectional microphone 3 Third omnidirectional microphone 4 First high-pass filter 5 Second high-pass filter 6 Third high-pass filter 7 First 8 Second phase shifter 9 Third phase shifter 10 First subtractor 11 Second subtractor 12 Third subtractor 13 First equalizer 14 Second equalizer 15 Third Equalizer 16 First variable amplifier 17 Second variable amplifier 18 Third variable amplifier 19 First controller 20 Second controller 21 First mixer 22 Second mixer

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koyo Ono 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-5-260585 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) H04N 5/225 H04R 1/40 320 H04R 3/00 320

Claims (2)

(57) [Claims] 1. A first and a second omnidirectional microphone arranged in a straight line in a forward direction at an interval from each other, and a vertical line segment connecting the first and second omnidirectional microphones. A third omnidirectional microphone arranged on a branch line, first and third phase shifters connected to the first omnidirectional microphone, and a second omnidirectional microphone connected to the second omnidirectional microphone Second and third high-pass filters, a first high-pass filter and a second phase shifter connected to the third omnidirectional microphone, and an output of the first high-pass filter for the first shift. The first to subtract the output of the phaser
, A second subtractor for subtracting the output of the second phase shifter from the output of the second high-pass filter, and a second subtractor for subtracting the output of the third high-pass filter from the output of the third high-pass filter. A third subtractor for subtracting the output, a first equalizer for equalizing the output of the first subtractor, a second equalizer for equalizing the output of the second subtractor, and the third subtraction A third equalizer for equalizing the output of the amplifier, a first variable amplifier for varying the output of the first equalizer, and a second variable amplifier for varying the output of the second equalizer.
, A third variable amplifier for varying the output of the third equalizer, a first controller for controlling the first and second variable amplifiers, and controlling the third variable amplifier A second controller, a first mixer that mixes the outputs of the first and third variable amplifiers, and a second mixer that mixes the outputs of the second and third variable amplifiers A microphone device characterized by the following. 2. The three omnidirectional microphones are arranged so that their main axes are parallel and in the same direction, and the three omnidirectional microphones are fixed so as to vibrate integrally. 2. The microphone device according to 1.