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JPH1079877

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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
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DESCRIPTION JPH1079877
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
camera integrated VTR having a function of zooming and photographing a lens, and more
particularly to a camera integrated VTR having a zoom microphone function.
[0002]
2. Description of the Related Art A camera-integrated VTR has a zoom function capable of
zooming and photographing a lens at an arbitrary angle of view desired by a photographer.
Moreover, the stereo microphone which can record the sound of each right and left is attached.
Furthermore, there is also a model having a zoom microphone function of changing the
directivity of the stereo microphone and recording so that the correlation with the zoom function
of the lens can be taken in accordance with the zoom function of the lens.
[0003]
An example of an article related to the zoom microphone function is described on pages 39 to 46
of the magazine "Video Capa" (Learning Research Inc .; December 1994), an article related to the
microphone performance of the video camera. There is an article of the zoom microphone
function using four microphones as "a zoom effect obtained by adding and subtracting signals
from four microphone capsules".
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[0004]
FIG. 2 shows a block diagram of a zoom microphone function using four microphones, and the
operation thereof will be described.
[0005]
The zoom microphone function using the conventional four microphones is configured by the
front microphone pair 1c, 1d facing each other as shown in FIG. 2 and the rear microphone pair
1e, 1f arranged 180 ° opposite to each other. 1c and microphone 1d are added to add front side
signal F, microphone 1e and microphone 1f are added to add rear side signal Re, microphone 1c
and microphone 1e are added to add left signal L, microphone 1d and microphone 1f to create
right signal Ri Do.
The signals F, Re, L, Ri generated by the respective addition circuits 2a, 2b, 2c, 2d are input to
the zoom processing circuit 3. The zoom processing circuit 3 discriminates the zoom position
information 4 provided from the lens 5, changes the addition / subtraction ratio of the signals F,
Re, L and Ri, and creates an audio signal so as to be correlated with the angle of view of the lens.
Output. For example, when the lens is on the telephoto side, by adding and subtracting the signal
F and the signal Re to emphasize the sound on the front side and further weakening the signals L
and Ri, as shown in FIG. It is possible to collect the sound of the far side on the front side. When
the lens is on the wide-angle side, the signals L and Ri are enhanced and the signals F and Re are
reduced to obtain directivity 7b as shown in FIG. I can collect sound.
[0006]
However, in the prior art, in order to realize the zoom microphone function, it is necessary to use
four microphones and four adder circuits for adding the respective signals, and a camera for
which downsizing and cost reduction are required In the integral type VTR, the arrangement
space and the parts cost become problems.
[0007]
SUMMARY OF THE INVENTION According to the prior art described above, in order to realize
the zoom microphone function, four microphones and four adder circuits must be used. In the
camera integrated type VTR required to lower the price, the arrangement space and the parts
cost have been problems.
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[0008]
The present invention was devised to solve the above-mentioned problems, and its object is to
configure a pseudo zoom microphone function similar to the zoom microphone function using a
total of two microphones, one each for left and right, and a phase difference matrix circuit. It is
an object of the present invention to provide a zoom microphone function of a compact and
inexpensive camera integrated VTR by facilitating the arrangement of the microphone.
[0009]
SUMMARY OF THE INVENTION The above problem is solved by providing a main unit with one
microphone each for left and right, a phase difference matrix circuit for separating the
microphone signal left and right, and a signal for the phase difference matrix circuit based on
zoom position information. This can be realized by providing a zoom processing circuit that
varies the subtraction ratio of.
[0010]
According to the present invention, the left and right microphones are arranged in the same
direction in the main unit, and the sounds collected by the microphones are input to the phase
difference matrix circuit.
In this phase difference matrix circuit, the sound signals are separated so that the sound from the
left and right microphones input does not enter the R side and the sound on the right side does
not enter the L side.
Further, the zoom processing circuit changes the degree of separation of the left and right voices
of the phase difference matrix circuit according to the zoom position information so as to be
correlated with the zoom position of the lens, thereby changing the directivity of the microphone
voice.
[0011]
With this configuration, when the zoom position is at the telephoto position, it becomes
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substantially monaural directivity centered on the front as shown in FIG. 3A, and when the zoom
position is at the wide angle, as shown in FIG. It becomes directional and enhances the sense of
stereo.
As a result, it is possible to realize a pseudo zoom microphone function similar to the zoom
microphone function with two microphones, facilitate the arrangement of the microphone, and
provide the zoom microphone function of a compact and inexpensive camera-integrated VTR. .
[0012]
The principle of the phase difference matrix circuit for separating the left and right sounds will
be described with reference to FIG.
[0013]
In the state shown in FIGS. 4 and 5, the sound from the sound source is input to each of the L
and R microphones.
At this time, the L side sound is delayed in phase by the distance L between the microphones
than the R side sound and is input.
In the equation, the distance between microphones L and the speed of sound S = delay time T. An
example of a waveform measured using a single signal is shown in FIG. The L-side signal is
delayed in phase from the R-side signal by the delay time T. Therefore, the R-side signal input to
the L-side microphone can be canceled by creating a signal R2 in which the R-side signal is
delayed by the same amount as the delay time T using the delay circuit and subtracting the signal
R2 from the L-side signal. . By providing a delay circuit and a subtraction circuit on each of the L
side and the R side as shown in FIG. 5, it is possible to separate the left and right sounds and to
increase the sense of stereo.
[0014]
The technology of the phase difference matrix circuit for separating the left and right sounds is
described on pages 79 to 80 of the magazine "TV Technology" (Electronic Technology Publishing
Co., Ltd .; July 1989).
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[0015]
BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will
be described below with reference to the drawings.
[0016]
FIG. 1 is a block diagram of a camera-integrated VTR according to an embodiment of the present
invention, wherein 1a is an L-side microphone, 1b is an R-side microphone, 3 is a zoom
processing circuit, 4 is zoom position information, 5 is a lens, 6a Is an L-side delay circuit, and 6b
is an R-side delay circuit.
[0017]
FIG. 3 is a schematic view showing the directivity of the microphone. FIG. 3A shows the
directivity when the zoom lens is in the telephoto position.
(B) shows the directivity when the zoom lens is at the wide angle position.
[0018]
The present invention applies the phase difference matrix circuit described in FIG. 4 as shown in
the block diagram of the camera integrated VTR in FIG.
The audio signals collected from the microphones 1 a and 1 b facing in the same direction are
input to the zoom processing circuit 3.
Further, the audio signals L2 and R2 delayed by the delay circuits 6a and 6b are generated from
the audio signals collected from the microphones 1a and 1b, and are input to the zoom
processing circuit 3. The zoom processing circuit 3 subtracts the audio signal R2 input from the
R side and delayed by the delay circuit from the audio signal on the L side. The audio signal L2
input from the L side and delayed by the delay circuit is subtracted from the audio signal on the
R side. Furthermore, the zoom position information 4 input from the lens 5 is analyzed, and the
subtraction ratio of each of the L side and the R side is changed according to the zoom position.
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When the zoom position is on the wide angle side, the subtraction ratio is maximized, and the
respective unnecessary signals on the L side and the R side are offset. Thereby, the directivity as
shown in FIG. 3B is realized to obtain stereo feeling. When the zoom position is on the telephoto
side, the subtraction ratio is minimized, and the L side and R side signals are output as they are.
Since the left and right microphones face in the same direction, substantially the same signal is
input to the L-side and R-side signals. Thus, a monaural sound as shown in FIG. 3B can be
obtained. Further, if the subtraction ratio is changed by adjusting the zoom position from wide
angle to telephoto, the pseudo zoom microphone can be obtained.
[0019]
By configuring in this manner, the audio signal input from each of the left and right microphones
can be correlated with the angle of view by using a pseudo zoom processing circuit applying a
phase difference matrix circuit. By changing the sensitivity, it is possible to realize a pseudo zoom
microphone function similar to the zoom microphone function with two microphones, and it is
easy to arrange the microphone and the zoom microphone function of the compact and
inexpensive camera integrated VTR Can be provided.
[0020]
According to the present invention, the audio signal input from each of the left and right
microphones can be correlated with the zoomed angle of view using a pseudo zoom processing
circuit to which a phase difference matrix circuit is applied. By changing the directivity of the
microphones, it is possible to configure a pseudo zoom microphone function similar to the zoom
microphone function with a total of two microphones, one each for each of the left and right, and
the phase difference matrix circuit, facilitating the arrangement of the microphones. In addition,
the zoom microphone function of the compact and inexpensive camera integrated VTR can be
provided.
[0021]
Brief description of the drawings
[0022]
1 is a block diagram of a camera-integrated VTR according to an embodiment of the present
invention.
[0023]
2 is a block diagram of a conventional camera integrated VTR.
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[0024]
3 is an explanatory view of the directivity of the camera integrated VTR according to the present
invention.
[0025]
4 is an explanatory view of a phase difference matrix circuit.
[0026]
5 is an explanatory view of a phase difference matrix circuit.
[0027]
6 is an explanatory view of the directivity of the conventional camera integrated VTR.
[0028]
Explanation of sign
[0029]
1a, 1b, 1c, 1d, 1e, 1f ... microphone, 2a, 2b, 2c, 2d ... addition circuit, 3 ... zoom processing circuit,
4 ... zoom position information, 5 ... lens, 6a, 6b ... delay circuit.
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