JPS6362500A - Video camera - Google Patents

Abstract

PURPOSE:To easily and naturally collect a sound corresponding to the distance of an object by changing the sound volume and the directivity of a microphone by using the position encoder output signal of a focusing lens and the position encoder output signal of a zoom lens. CONSTITUTION:When the object is at a long distance, a switch 6 goes to ON by the output signal of an encoder 3, and two output signals from the microphones A4 and B5 are mixed by a mixer 9. In such a case regarding the sound from the front of the microphone, the two microphones are in an opposite phase, while regarding the sound from a lateral direction, they are in an inphase. Therefore, after the outputs from the microphones 4, 5 are amplified by amplifiers 7, 8, the difference between the two output signals is mixed by the mixer 9, and outputted. Thus, the natural sound collection can be easily executed corresponding to the distance of the object.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a video camera.

BACKGROUND TECHNOLOGY - In I'IQ, a video camera uses one omnidirectional or unidirectional microphone, and its volume remains constant regardless of whether the image is zoomed.

Therefore, even when zooming in on a person close to you or a bird far away, the volume does not change, which is unnatural and inconvenient.

Conventionally, there has been a microphone shown in FIG. 2 as a microphone with improved directivity in order to improve the characteristics when zoomed in.

In FIG. 2, the microphone 21 is composed of three microphones 21a, 2lb, and 21c, each having unidirectionality.

Two microphones 22a and 22c are arranged facing forward with respect to the sound source 22, and one microphone 22b is arranged facing backward.

The overall characteristics of these microphones are three directional characteristics as shown in FIG.

The omnidirectionality shown in FIG. 3a is obtained by combining microphones 22a and 22b.

Figure 3 shows the primary sound pressure gradient unidirectional characteristic, which is the characteristic of one microphone.

Figure 3C shows the secondary sound pressure gradient unidirectional characteristic, and the volume is displaced by rotating the zoom ring of the television camera.
When mixing the output from the microphones, the mixing ratio is varied by a predetermined amount to change the directivity.

(For example, Japanese Patent Application Laid-Open No. 56-35596.) Furthermore, as the directivity of a single microphone has become narrower, some have increased the volume. (The directionality and sound were changed only in conjunction with the above operations, and sound was collected regardless of the distance of the subject, creating an unnatural sound.)

The present invention provides a video camera that eliminates the above-mentioned problems and has a microphone that has a difference in zooming between close and long distances and can collect natural sound.

Means for Solving the Problems In order to solve the above problems, the video camera of the present invention uses a signal source unique to a video camera with an autofocus mechanism. The position encoder output signal of the focusing lens is used to turn one of the two microphones on and off, and the frequency characteristics of the gain adjustment/equalization amplifier are adjusted, and the zoom position encoder output signal is used to adjust the gain.・By adjusting the gain of the equalization amplifier, the directivity and volume of the microphone are adjusted.

Effect By using the above means, when a nearby sound source is zoomed, the volume increases while maintaining unidirectionality, and when a distant sound source is zoomed, the directivity is narrowed and the volume is also increased. By increasing the size, surrounding sounds are included depending on the distance of the subject, and the sound becomes louder as the image approaches.

Therefore, it is possible to collect sound from a place far away from the sound source with a natural illusion depending on the distance.

Embodiment Hereinafter, an embodiment of the video camera of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing one embodiment of the present invention.

In FIG. 1, 1 indicates a zoom lens, 2 is a zoom position encoder attached to the zoom lens,
Information on the focal length of the photographing zoom lens is converted into a 2-bit digital value and output.

3 is a focusing lens position encoder which converts information corresponding to the position up to the subject into a 2-bit digital value and outputs it. 4 is Hana-directional microphone A
, 5 is a unidirectional microphone B, which is arranged in consideration of its spatial position with respect to the microphone A of 4. ,
6 is a switch for turning microphone B ON-OFF, 7 and 8 are amplifiers, and 9 is an output to a unidirectional microphone and a switch for unidirectional microphone B.
It is a mixer that mixes the difference between the outputs of . Reference numeral 10 denotes a gain adjustment/equalization amplifier.J-Y The operation of one embodiment will be described below with reference to the drawings.

The 4 ψ-directional microphones A and the 5 single-purpose ``ficrophones B'' are arranged with an interval of d (d-λ/2).

FIG. 4 is a characteristic diagram showing the directivity characteristics of the microphone of the present invention.

As shown in (dl, (el, (f)) in Figure 4,
When the subject is far away, the switch 6 is turned on by the output signal of the focusing lens position encoder 3, and the two outputs of the unidirectional microphone A (4) and the unidirectional microphone B (5) are output. The signals are mixed in mixer 9.

At this time, sounds from the front of the microphones are out of phase between the two microphones, while sounds from the sides are in phase.

Therefore, after the outputs of the two microphones 4 and 5 are amplified by the amplifiers 7 and 8, the difference between the two output signals is mixed by the mixer 9 and output.

The microphone has a narrow directional characteristic, with high sensitivity in the forward direction and low sensitivity in the lateral direction. The frequency characteristics of the microphone are 6 d with the peak at the set wavelength λ.
Since the characteristic decreases toward the low frequency side at 10 ct, the frequency characteristic of the gain adjustment/equalization amplifier 10 is raised in the low frequency range by the output signal of the focusing lens position encoder 3.

In addition, the gain adjustment/equalization amplifier 1 is controlled by the Buddhist painting/standard or telephoto signal of the output signal of the zoom position encoder 2
(d) of FIG. 4 by adjusting the gain of 0.

The volume is varied like (el, (fl).

The subject is tag in Figure 4, 11. When the camera is at a short distance as shown in tel, the switch 6 is turned OFF by the output signal of the focusing lens position encoder 3, and only the unidirectional microphone A (4) operates, and the gain adjustment/equalization amplifier is turned off. The frequency response of 10 becomes flat and the microphone becomes unidirectional.

At this time as well, only the volume can be varied by adjusting the gain of the gain adjustment/equalization amplifier 10 using the Buddhist painting/standard or telephoto signal of the output signal of the zoom position encoder 2.

In other words, the gain is controlled by the zoom position encoder 2, and the output signal of the focusing lens position encoder is used to turn the microphone B switch 0N-0.
In addition to adjusting the frequency characteristics of the FF and the gain adjustment/equalization amplifier 10, the overall directional characteristics and volume of the microphone are controlled according to the distance of the subject and the information of the Buddhist painting, standard, or telephoto of the zoom lens. .

As described above, according to the present invention, the directivity and volume of the two microphones are adjusted using the output signals of the focusing lens position encoder and the zoom lens position encoder, and the volume is adjusted according to the distance of the subject and the state of the zoom lens. can be controlled and can collect sound in a natural way.

A video camera with autofocus is equipped with a zoom lens position encoder and an autofocus position encoder, and only requires the addition of one microphone and a simple circuit such as a mixing circuit.

Effects of the Invention The present invention is a signal source specific to a video camera with an autofocus mechanism. Using the focusing lens position encoder output signal and the zoom lens position encoder output signal as control signals, you can easily change the volume and directivity of the microphone to collect natural sound according to the distance of the sound source and the zooming state. It has a new effect in that it can be

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an embodiment of the video camera of the present invention;
The figure shows a configuration diagram of a conventional video camera microphone.
FIG. 3 is a directional characteristic diagram of a microphone of a conventional video camera, and FIG. 4 is a characteristic diagram showing directional characteristics of a microphone of a video camera according to the present invention. 1...Zoom lens, 2...Zoom position encoder, 3...Focusing lens position encoder, 4...Microphone A, 5...
...Microphone B, 6...Switch, 7
．． 8...Amplifier, 9...Mixer, 10
...Gain adjustment/equalization amplifier.

Claims (1)

[Claims] Focusing lens position encoder output signal, 2
Switching on and off one of the two microphones, adjusting the frequency characteristics of the gain adjustment/equalization amplifier, and adjusting the gain of the gain adjustment/equalization amplifier using the zoom position encoder output signal. A video camera characterized in that it is equipped with a mechanism for adjusting the directivity and volume of a microphone.