JP3064690B2 - 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). In order to obtain 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 a 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, and a first phase shifter connected to the first omnidirectional microphone A second high-pass filter connected to the second omni-directional microphone, a first high-pass filter and a second phase shifter connected to the third omni-directional microphone, and a first high-pass filter A first subtractor for subtracting the output of the first phase shifter from the output of the second phase shifter; a second subtractor for subtracting the output of the second phase shifter from the output of the second high-pass filter; From the output of the high-pass filter to the first phase shifter A third subtracter for subtracting the force, first
A first equalizer for equalizing the output of the subtractor of
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, and a second equalizer. A second variable amplifier for varying the output of the equalizer, a third variable amplifier for varying the output of the third equalizer, a first controller for controlling the first and second variable amplifiers, A second controller for controlling the output of the first and third variable amplifiers, and a second mixer for mixing the outputs of the second and third variable amplifiers. It has a configuration of a vessel.

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, 2 denotes a second omnidirectional microphone arranged in a straight line in a forward direction at an interval from the first omnidirectional microphone, and 3 denotes a first omnidirectional microphone 1 and a second omnidirectional microphone. The third omnidirectional microphone is arranged on a vertical bisector of a line connecting the two omnidirectional microphones 2.
Here, the direction of the directivity main axis of the center channel is the first direction.
In the direction from the omnidirectional microphone 1 to the second omnidirectional microphone 2 in the same direction as the directional main axis of the microphone device. The direction of the directivity main axis of the stereo right channel is in the direction from the first omnidirectional microphone 1 to the third omnidirectional microphone 3, and similarly, the direction of the directivity main axis of the stereo left channel is Third
In the direction from the omnidirectional microphone 3 to the second omnidirectional microphone 2. Assuming that an angle when the directivity main axis of the right channel is viewed from the directivity main axis of the microphone device is φ, an angle when the directivity main axis of the left channel is viewed from the directivity main axis of the microphone device is −φ. d ₁ is the third omnidirectional microphone 3 and the first omnidirectional microphone 1
And the distance between the second omnidirectional microphone 2 and
d ₂ is the distance between the first omnidirectional microphone 1 and the second omnidirectional microphone 2. Reference numeral 4 denotes a first high-pass filter that receives the output V ₃ of the third omnidirectional microphone 3 and cuts the low-frequency range. Reference numeral 5 denotes a band that receives the output V ₂ of the second omnidirectional microphone 2 and cuts the low-frequency range. A second high-pass filter, 6 is a first phase shifter that receives the output V ₁ of the first omnidirectional microphone 1 and shifts it by the phase angle θ ₁ , 7 is an output V _{3 of the} third omnidirectional microphone ₃ And a _second phase shifter 8 for shifting the output of the first phase shifter 6 from the output of the first high-pass filter 4.
, A subtractor 9 for subtracting the output of the second phase shifter 7 from the output of the second high-pass filter 5, and 10 a first phase shifter from the output of the second high-pass filter 5 6, a third equalizer for equalizing the output characteristic of the first subtractor 8, and 12 a second equalizer.
The second equalizer 13 equalizes the output characteristic of the subtracter 9 of the first embodiment, and the third equalizer 13 equalizes the output characteristic of the third subtractor 10. 14 is the first equalizer 1
1, a first variable amplifier for varying the output level of the second equalizer 12, 15 a second variable amplifier for varying the output level of the second equalizer 12, and 16 a third variable amplifier for varying the output level of the third equalizer 13. , 17 are the first and second variable amplifiers 1 in synchronization with the change of the zoom signal from wide angle to telephoto.
A first controller 18, which controls the output levels of the fourth and fifth amplifiers to be continuously attenuated, is synchronized with the change of the zoom signal from wide angle to telephoto so that the output level of the third variable amplifier 16 becomes continuous. A second controller that controls to increase to
Reference numeral 9 denotes a first mixer for mixing the outputs of the first and third variable amplifiers 14 and 16, and reference numeral 20 denotes a second and third variable amplifier 15,
16 is a second mixer for mixing 16 outputs.

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

First, the first high-pass filter 4 and the second
The cutoff frequency (f_C )than
In the high middle and high frequency range, the first and second variable amplifiers 14 and 15
Input signal V_R1, V_L1Is the orientation of the microphone device
Directivity with the direction of angles φ and −φ from the main axis
The directivity pattern is shown in FIG. 2, and the third variable amplification
Signal V input to the unit 16_C1 Is the orientation of the microphone device
The directivity becomes the main axis, and the directivity pattern is shown in FIG.
Becomes Next, the cutoff frequency (f_C ) Lower bass
In the range, the input signal V_R1, V_C1Is the first omnidirectional micro
Output V of phone 1 ₁ Only the input signal V_L1Is the third
Output V of the omnidirectional microphone 3_Three Only
V_R1, V_L1, V_C1Are omnidirectional.

Also, the first and second variable amplifiers 14 and 15
The output levels V _R2 and V _L2 of the third variable amplifier 16 are controlled by the first controller 17 that has received the zoom signal, and the output level V _C2 of the third variable amplifier 16 is the second controller 18 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 14 the output signal V _C2 of the third variable amplifier 16 is mixed in the first mixer 19, the output signal V _R is the right channel output, the second The output signal V _L2 of the variable amplifier 15 and the output signal V _C2 of the third variable amplifier 16 are mixed by the second mixer 20,
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 directivity.
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. In addition, the directivity of the mid-high range related to the sound image localization of the center channel and each stereo channel can be freely set by the time constant of the phase shifter,
Moreover, since the directivity main axes (φ, −φ) of the right and left channels of the stereo related to the spread of the stereo can be freely set by disposing the third omnidirectional microphone 3, 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. In addition, omnidirectional microphones are not significantly affected by diffraction or the like, unlike directional microphones.
Easy to attach to equipment. In addition, it is also possible to correct the influence of diffraction and the like by a circuit.

As shown in FIG. 1, when 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, the center becomes In the directivity regions of the middle and high frequency ranges of the channel and the left and right channels, the attenuation of the sound pressure sensitivity in the 90-degree direction with respect to the 0-degree direction about the respective main axes of the directivity is more advantageous than the non-directionality with respect to vibration. Becomes

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

[0021]

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 arranged on a vertical bisector of the connecting line segment, a first phase shifter connected to the first omnidirectional microphone, and a connection to a second omnidirectional microphone A second high-pass filter, a first high-pass filter and a second phase shifter connected to a third omnidirectional microphone, and a first phase-shifter based on the output of the first high-pass filter. A first subtractor for subtracting the output;
A second subtractor for subtracting the output of the second phase shifter from the output of the second high-pass filter, and a third subtraction for subtracting the output of the first phase shifter from the output of the second 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, and 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, and a third variable amplifier for varying the output of the third equalizer A first controller for controlling the first and second variable amplifiers, a second controller for controlling the third variable amplifier, and a first controller for mixing the outputs of the first and third variable amplifiers. And a second mixer for mixing the outputs of the second and third variable amplifiers, and the low frequency range is omnidirectional and the mid-high frequency range is directional, so that the Not only is possible to pick up the zoom of the camera, but also resistant to noise such as vibration, proximity noise, and wind. As a result, it can be used for devices that have internal vibration or noise sources, such as video-integrated cameras. Built-in is possible, making these devices smaller and lighter. The ability.

Further, the main axes of the three omnidirectional microphones are arranged so as to be parallel and in the same direction, and the three omnidirectional microphones are fixed so as to 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.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st omnidirectional microphone 2 2nd omnidirectional microphone 3 3rd omnidirectional microphone 4 1st high-pass filter 5 2nd high-pass filter 6 1st phase shifter 7 2nd phase shifter 8 1st subtracter 9 2nd subtracter 10 3rd subtracter 11 1st equalizer 12 2nd equalizer 13 3rd equalizer 14 1st variable amplifier 15 2nd variable amplifier 16 3rd variable Amplifier 17 First controller 18 Second controller 19 First mixer 20 Second mixer

Continuation of the front page (72) Inventor: Kono Ono 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-4-37266 (JP, A) JP-A-55-143896 JP, A) JP-A-63-153965 (JP, A) JP-A-59-72295 (JP, A) JP-A-62-42381 (JP, U)

Claims (2)

(57) [Claims] 1. A first and a second omnidirectional microphones arranged in a straight line in a 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, and a first transferer connected to the first omnidirectional microphone A phaser, a second high-pass filter connected to the second omnidirectional microphone, a first high-pass filter and a second phase shifter connected to the third omnidirectional microphone, A first subtractor for subtracting the output of the first phase shifter from the 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 second subtractor for subtracting the output of the first phase shifter from the output of the second high-pass filter. 3, 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 that performs
A first variable amplifier for varying the output of the 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 first and second variable amplifiers, a second controller for controlling the third variable amplifier, and a first controller for mixing outputs of the first and third variable amplifiers A microphone device comprising: a mixer; and a second mixer for mixing outputs of the second and third variable amplifiers. 2. The microphone device according to claim 1, wherein 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. .