JPH02238778

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DESCRIPTION JPH02238778
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
microphone which picks up sound simultaneously with video recording, and a video camera
equipped with the same. 2. Related Art In recent years, the spread of consumer video cameras is
remarkable. Most of these consumer video cameras have zoom lenses, while their built-in
microphones have a fixed directivity and the audio recording method is also monaural, so there is
a lack of integration between video and audio . Therefore, recently, there have also appeared
models in which the audio recording system is a stereo system. Also, in order to perform
recording in which video and audio are integrated, a microphone has been developed in which
the output level and directivity of the microphone change in accordance with the zoom of the
video. Hereinafter, an example of a video camera provided with the above-mentioned
conventional microphone will be described with reference to the drawings. FIG. 6 shows an
example of a video camera provided with a conventional microphone. In FIG. 6, 1 is a lens unit, 2
is a microphone unit unit, 3 is a directivity combining unit, and 4 is a gain adjustment unit. In the
lens unit 1, 5 is a zoom lens, 6 is a zoom ring, 7 is a reflective member, 8 is a light sensor with a
light emitting / receiving element (hereinafter referred to as a photo sensor), and a is rotation of
the zoom ring detected by the photo sensor 8. A signal representing an angle (hereinafter
referred to as a zoom ring rotation angle signal), b is a signal representing a current zoom
magnification (hereinafter referred to as a zoom magnification signal), 9 is a zoom ring rotation
angle signal a converted to a zoom magnification signal b Encoder (hereinafter referred to as a
zoom magnification encoder). The microphone unit unit 2 is a unidirectional microphone unit 11,
12. 13. It consists of four of fourteen. マイクロホンユニット11. The lens 14 is directed in
the same front direction as the lens, and is disposed on a straight line in the front direction at
intervals. Microphone units 12 and 13 are inclined 45 ° to the left and right with respect to the
front direction to make microphone units} 11. It is arranged on the same straight line as 14. d, e,
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f and g are the outputs of the respective microphone units. In the directivity synthesis unit 3, 15
is a phase shifter, 16. 17, l8 is an adder, 19, 20. 21 is a variable attenuator. 22. In the gain
adjustment unit 4 23 is a variable attenuator. O is the output of the right channel and p is the
output of the R channel. The operation of the video camera configured as described above will be
described below with reference to FIG. First, in the lens unit 1, the zoom magnification of the
zoom lens 5 is changed by rotating the zoom ring 6.
The reflective material 7 is wound around the zoom ring 6, and the photo sensor 8 is disposed to
face the reflective material 7. The reflectors 7 are arranged in three rows, and there are a portion
where the reflectors exist and a portion where the reflectors do not exist on each row. Each row
is a digital bit, and the presence or absence of a reflector corresponds to digital "l" and "0". The
photosensor 8 detects the rotation angle of the zoom ring 6 by reading the pattern of the portion
of the reflective material 7 facing the photosensor 7, and outputs it as a rotation angle signal a.
Since there are eight patterns of 3 bit x 2 ways, the rotation angle of the zoom ring 6 is detected
in eight steps. In this embodiment, although the number of reflectors is three, the number of
stages of detection increases as the number of columns is increased, and more accurate detection
is possible. The rotation angle signal a is converted into the zoom magnification signal b by the
zoom magnification encoder 9 and output to the outside of the lens unit. The outputs a, b, c, d of
the microphone unit output from the microphone unit 2 are delayed by the directivity synthesis
unit 3. The directivity of the microphone is synthesized by amplification, attenuation and addition
/ subtraction. First, the output d of the micro-bon unit 4 is delayed by the phase shifter 15. The
output h and the output g of the microphone unit 17 are added by the adder l6 to become the
superdirective output i. Also, the outputs e of the microphone unit 12 and the outputs f of 13
become stereo outputs as they are. The outputs e, f of this stereo and the outputs of
superdirectivity i have variable attenuators 19.20. Attenuated by 21 and output j. After becoming
k, l, the adder 17. It mixes in 18 and becomes m and n. At this time, the attenuation amount of
the variable attenuator is controlled by the zoom magnification signal b, and the mixing ratio of
stereo is increased when the zoom magnification is low, and the mixing ratio of superdirectivity
is increased when the zoom magnification is high. In the gain adjustment unit 4, the outputs m
and n of the microphones after directivity synthesis are variable attenuators 22. The gain
changes according to 23. At this time, the variable attenuator 22. The attenuation amount 23 is
controlled by the zoom magnification signal b. When the zoom magnification is low, the
attenuation amount is large, and when the zoom magnification is high, the attenuation amount is
small. In this way, the gain is controlled according to the change of the zoom magnification, and
becomes the outputs 0, P of the left and right channels of the microphone. As described above, in
the conventional example, the output level of the microphone increases as the zoom
magnification increases, and the directivity also changes from stereo to superdirectivity. The
sound changes.
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SUMMARY OF THE INVENTION However, in the configuration as described above, although it is
possible to change video and audio in conjunction, it has not been known how to change audio
with respect to video. Therefore, there is a problem that sufficient sense of unity can not be
obtained. SUMMARY OF THE INVENTION In view of the above problems, the present invention
provides a microphone and a video camera having an output level and directivity such that the
volume and the ambient sound change in accordance with human vision and hearing during
reproduction. MEANS FOR SOLVING THE PROBLEMS In order to solve the above-mentioned
problems, the microbon of the present invention is a directional combining means capable of
controlling the delay amount and amplification / attenuation amount with a plurality of
microphone units and zoom magnification signals supplied from the outside. And an
amplification / attenuation means capable of controlling the gain with a zoom magnification
signal supplied from the outside. With this configuration, the output of the microphone unit is
synthesized by the directivity synthesis means. Then, after the synthesis, a gain proportional to
the power of the zoom magnification is given by the above amplification and attenuation means.
Alternatively, after synthesis, gain is provided by the amplification / attenuation means, and the
output level is made different even at the same magnification when the magnification is
increased or decreased by the amplification / attenuation means. Alternatively, after the
synthesis, a gain proportional to the power of the zoom magnification is given by the above
amplification / attenuation means, and the exponent part of the power takes different values
when the magnification increases and decreases. The directivity synthesis may be constant
without being controlled by the zoom magnification signal. Also, one microphone unit may be
provided, and the gain may be controlled by the above amplification / attenuation means on this
output. The video camera according to the present invention comprises the microphone
according to the present invention, means for detecting the zoom magnification of the lens of the
video camera, means for converting the zoom magnification into a zoom magnification signal,
and means for outputting the zoom magnification signal to the outside of the video camera. It has
the composition of. Further, the microphone of the present invention may be incorporated in this
video camera. Operation According to the present invention, when recording video and audio
according to the above-described configuration, the gain of the circuit of the microphone
changes in accordance with the change in the zoom magnification of the lens, so the output level
of audio also changes. This change is a change based on the characteristics of human vision and
hearing during reproduction. As a result, when reproduced, the volume changes appropriately in
accordance with the zoom of the video, and a sense of unity between video and audio can be
obtained. Furthermore, if the directivity is appropriately changed in accordance with the change
in zoom magnification, the ambient sound of the subject also changes in accordance with the
zoom of the video when reproduced, and the sense of unity between the video and the audio
becomes larger.
First Embodiment A video camera according to a first embodiment of the present invention will
be described with reference to the drawings. FIG. 1 is a block diagram showing a first
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embodiment of the present invention. In FIG. 1, 1 is a lens unit, 2 is a microphone unit unit, 3 is a
directivity combining unit, and 4 is a gain adjustment unit. In the lens unit 1, 5 is a zoom lens, 6
is a zoom ring, 7 is a reflective member, 8 is a light sensor with a light emitting / receiving
element (hereinafter referred to as a photo sensor), and a is rotation of the zoom ring detected by
the photo sensor 8. A signal representing an angle (hereinafter referred to as a zoom ring
rotation angle signal), b is a signal representing a current zoom magnification (hereinafter
referred to as a zoom magnification signal), 9 is a zoom ring rotation angle signal a converted to
a zoom magnification signal b Encoder (hereinafter referred to as zoom magnification encoder).
The microphone unit unit 2 is a unidirectional microphone unit 11. 12,13. It consists of
four of fourteen. マイクロホンユニット11. The lens 14 is directed in the same front direction
as the lens, and is disposed on a straight line in the front direction at intervals. The microphone
unit 12.13 is inclined 45.degree. To the left and right with respect to the front direction and the
microphone unit 11.13. It is arranged on the same straight line as 14. d, e, f and g are the
outputs of the respective microphone units. In the directivity synthesis unit 3, 15 is a phase
shifter, 16, 17.18 is an adder, '. 9, 20. 21 is a variable attenuator. In the gain adjustment unit 4, C
is a signal indicating whether the zoom magnification is increasing or decreasing (hereinafter
referred to as a zoom magnification change signal), and 1 o is an encoder that converts the zoom
magnification signal b into the zoom magnification change signal C ( Hereinafter referred to as a
zoom magnification change encoder), 22. 23 is a variable attenuator. Also, 0 is the output of the
right channel, and p is the output of the R channel. The operation of the video camera configured
as described above will be described below with reference to FIG. First, in the lens unit 1, the
zoom magnification of the zoom lens 5 is changed by rotating the zoom ring 6. The reflective
material 7 is wound around the zoom ring 6, and the photo sensor 8 is disposed to face the
reflective material 7. The reflectors 7 are arranged in three rows, and there are a portion where
the reflectors exist and a portion where the reflectors do not exist on each row. Each row
corresponds to a digital bit, and the presence or absence of a reflective material corresponds to a
digital "l" and "0 '". The photosensor 8 detects the rotation angle of the zoom ring 6 by reading
the pattern of the portion of the reflective material 7 facing the photosensor 7, and outputs it as
a rotation angle signal a.
Since there are eight patterns of 3 bit × 2, the rotation angle of the zoom ring 6 is detected in
eight stages. In this embodiment, although the number of reflectors is three, the number of
stages of detection increases as the number of columns is increased, and more accurate detection
is possible. The rotation angle signal a is converted into the zoom magnification signal b by the
zoom magnification encoder 9 and is output to the outside of the lens unit. The outputs a, b, c, d
of the microphone unit output from the microphone unit 2 are delayed by the directivity
synthesis unit 3. The directivity of the microphone is synthesized by amplification, attenuation
and addition / subtraction. First, the output d of the microphone unit 14 is delayed by the phase
shifter 15. The output h and the output g of the microphone unit 17 are added by the adder 16
to obtain a superdirective output i. Also, the outputs e of the microphone unit 12 and the outputs
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f of 13 become stereo outputs as they are. このステレ? , And superdirective i have variable
attenuators 19. 20. Attenuated by 21 and output j. After becoming k, l, the adder 17. It mixes
in 18 and becomes m and n. At this time, the attenuation amount of the variable attenuator is
controlled by the zoom magnification signal b so as to satisfy the following equation (1). For the
output m, Sou &
α · St−a + (1−α) ′ st * (1) S0: output mSZ + s + 1: superdirective output
iSLI: stereo output eα: superdirective mix Ratio (0 ≦ α ≦ 1) Zoom magnification large ······ α
large zoom magnification small ················· α small output n In the equation (1), S out is the output
n, B is It becomes the output f of a stereo. Here, in the zoom lens, the zoom magnification and the
angle of view have a relationship as shown in the following equation (2). Vθ: horizontal angle of
view of lens y: width of COD in horizontal direction β: zoom magnification (βf1) f0: focal length
of lens when β = 1, ie, when zoom magnification is low, angle of view is large The angle of view
is narrow when the zoom magnification is high. In other words, if the mixing ratio of stereo is
increased when the zoom magnification is low and the mixing ratio of superdirectivity is
increased when the zoom magnification is high according to the equation (1), the synthesized
directivity of the microphone is an image being photographed Adapt to changes in corners. In the
gain adjustment unit 4, first, the zoom magnification signal b is converted into the zoom
magnification change signal C by the zoom magnification change encoder 10. Also, the outputs m
and n of the microphones after directivity synthesis are the variable attenuators 22. The gain
changes according to 23. The setting of this gain is based on experiments as described below.
When a person speaking is recorded by a video camera and reproduced by a receiver and a
speaker, when the size of the person on the screen changes due to the zoom of the image, the
viewer feels a sense of unity between the image and the sound The results of examining the
amount of change in reproduced sound pressure are shown in FIG. 5, and FIG. 5 (a) shows a
decrease in zoom magnification when zoom magnification is increased (hereinafter referred to as
zoom-in). When (hereinafter referred to as zoom out. )である。 The horizontal axis plots the
magnification of change of zoom on a logarithmic scale, and the vertical axis plots the amount of
increase in sound pressure in dB. The relationship between the change magnification of the zoom
and the sound pressure is A = Z-log (V) ........ (3) A: Sound pressure increase amount (dB) 倍率 =
zoom change magnification Z = 0.3 (V <1) = 0.5 (V 1 1). Equation (3) indicates that when the
image is zoomed and its size is changed, changing the output level of the microphone by the
power of the zoom factor makes the image and the audio have a sense of unity, and zoom in and
zoom out It shows that the amount of change giving the bodily sensation is different. Based on
this, the zoom magnification change signal C is transmitted to the variable attenuator 22. The
amount of attenuation of 23 is controlled to satisfy the equation (3). Thus, the gain is controlled
in accordance with the change of the zoom magnification, and becomes the outputs o and p of
the left and right channels of the microphone. As described above, according to the present
embodiment, the means for detecting the zoom magnification of the image, and the case where
the output level of the microphone is changed in proportion to the power of the zoom
magnification of the video of the video camera and the zoom magnification increases The output
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of the microphone according to the change in the zoom factor is provided by providing means for
making the exponent part of the power different in the case of reduction and means for changing
the directivity characteristic of the microphone according to the zoom factor of the video of the
video camera. The level and directional characteristics change as shown in FIG. 5, and these
changes take into account the human visual and auditory sense at the time of reproduction.
Changes appropriately, and a sense of unity of video and audio can be obtained. Hereinafter, a
video camera according to a second embodiment of the present invention will be described with
reference to the drawings. FIG. 2 is a block diagram showing a second embodiment of the present
invention. In FIG. 2, 1 is a lens unit, 5 is a zoom lens, 6 is a zoom ring, 7 is a reflective member, 8
is a photosensor, a is a zoom ring rotation angle signal, b is a zoom magnification signal, and 9 is
a zoom ring rotation angle An encoder (hereinafter referred to as a zoom magnification encoder)
for converting the signal a into a zoom magnification signal b is the same as that of the first
embodiment.
A difference from the first embodiment is that the zoom magnification signal b is output to the
outside of the video camera. The operation of the video camera configured as described above is
similar to the operation of the lens unit 1 in the first embodiment. As described above, according
to the present embodiment, by providing means for detecting the zoom magnification of the
video and outputting the magnification information to the outside of the video camera, the
output level and directivity change in accordance with the zoom magnification information. If
recording is performed in combination with an external microphone, the volume and the ambient
sound of the subject change according to the zoom of the image when reproduced, and a sense of
unity of the image and the sound can be obtained. A microphone according to a third
embodiment of the present invention will be described below with reference to the drawings. FIG.
3 is a block diagram showing a first embodiment of the present invention. In FIG. 3, 2 is a
microphone unit, 3 is a directivity synthesis unit, and 4 is a gain adjustment unit. In the
microphone unit unit 2, 11. 12,13. 14 is a unidirectional microphone unit. d, e, f and g are
the outputs of the respective microphone units. In the directivity synthesis unit 3, 15 is a phase
shifter, 16. 17. 18, an adder; 19, 20. 21 is a variable attenuator. In the gain adjustment unit 4,
b is a zoom magnification signal, C is a zoom magnification change signal ', 22. 23 is a variable
attenuator. 0 is the right channel output and p is the R channel output. The above is the same as
the first embodiment. The difference from the first embodiment is that the zoom magnification
signal b is supplied from the outside of the microphone. The operation of the video camera
configured as described above is the same as the operation of the microphone unit unit 2, the
directivity synthesis unit 3, and the gain adjustment unit 4 in the first embodiment. As described
above, according to the present embodiment, the output level of the microphone is changed in
proportion to the power of the zoom factor of the video of the video camera, and the exponent
part of the power is different when the zoom factor is increased or decreased. If recording is
performed in combination with a video camera that supplies information on zoom magnification
by providing means for changing the directivity characteristic of the microphone according to
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the zoom magnification of the video of the video camera, change in the zoom magnification Since
the output level and directivity of the microphone change as shown in Fig. 5 and these changes
take into account human vision and hearing during reproduction, the volume of the image
according to the zoom when reproduced is The ambient sound of the subject changes
appropriately, and a sense of unity between video and audio can be obtained.
In the first and third embodiments, the variable attenuators 19, 20. Although the attenuation
amount 21 is controlled by the zoom magnification signal to change the directivity of the
microphone, the control may not be performed and the directivity may be fixed and only the
change of the output level may be performed. Also, first. In the third embodiment, the number of
microphone units in the microphone unit portion is four, but the present invention can be
implemented if the number of units is more than one. Also, even in the case of one unit, the
present invention can be implemented by changing only the output level. Effects of the Invention
As described above, the present invention provides means for detecting the zoom magnification
of an image, changes the output level of the microphone in proportion to the power of the zoom
magnification of the video of the video camera, and increases the zoom magnification. By
combining the means for making the exponent part of the power differ between the case and the
case and the means for changing the directional characteristic of the microphone
correspondingly to the zoom factor of the video of the video camera, the microphone The output
level and directivity change as shown in Fig. 5, and these changes take into account the human
visual and auditory sense at the time of reproduction. The sound changes properly, and a sense
of unity between video and audio can be obtained.
[0002]
Brief description of the drawings
[0003]
FIG. 1 is a block diagram showing the first embodiment of the present invention, FIG. 2 is a block
diagram showing the first embodiment of the present invention, and FIG. 3 is a block diagram
showing the first embodiment of the present invention Fig. 4 is a graph showing the relationship
between the change magnification of the zoom and the amount of increase in sound pressure,
Fig. 5 is a diagram showing the change in output level and directivity according to the
embodiment of the present invention, and Fig. 6 is an example of the prior art Is a block diagram
showing FIG.
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1······················································································
· · · · · · · · · · · · · · · · · · · · · · · · · · ・Lens, 6 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Photo
sensor, 9 · · · · · · · · · zoom magnification encoder, lo · · · · zoom magnification Change encoder, II,
12, 13. 14 · · · · · · · Unidirectional microphone unit, l · · · · · · · phase shifter, 19, 20. 21,22.
23 ······· Variable attenuator. Name of agent Attorney Attorney Shigetaka Hino 1 person Ji 2 Figure
Figure (Q) (e- 冫
の の イ Q Q Figure (Q) left chi v '/ わ stone y 71) レ
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