JPH0497666A - Automatic tracking device for video camera - Google Patents

Abstract

PURPOSE:To avoid trouble of an object having an oscillator by moving an optical axis of a video camera in a direction in which a signal difference is minimized based on a voice signal obtained from vertical and horizontal pairs of plural microphones each having directivity. CONSTITUTION:Microphones 101, 102 have a directivity respectively and they are fixed to a direction so that each direction axis is always symmetrical with respect to an optical axis of a video camera. Detectors 103, 104 output a voltage in response to the quantity of an output of each microphone and a difference device 105 discriminates the quantity of voice output obtained from the microphones 101, 102 and a motor controller 106 drives a motor 107 to the right or to the left based on the result of discrimination and stops the motor when each voice output is equal to each other. The motor 107 drives the optical axis of the video camera and the microphones 101, 102. Thus, it is not required for a person or an object being a pickup object to carry an oscillator.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic tracking system for a video camera, which allows the video camera to be automatically directed to a subject.

[Conventional technology]

When automatically tracking a moving subject with a video camera,
In addition to means such as a pan head for moving or rotating the video camera toward the subject, it is also necessary for detecting the position of the subject. For this purpose, a technique has been proposed, for example, as disclosed in Japanese Patent Application Laid-Open No. 57-108769, in which a moving object side transmits sound waves or radio waves of a constant frequency, and the video camera side receives the waves.

[Problem to be solved by the invention]

When an automatic tracking system for a video camera is constructed using the above-mentioned conventional technology, there is a problem that, for example, the person or object that is the subject must have an oscillator, and it is not compatible with an automatic monitoring system that does not limit the subject. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic tracking system for a video camera that is highly versatile and eliminates the trouble of having a subject with an oscillator.

[Means to solve the problem]

In order to achieve the above object, the present invention uses one or both of the following configurations.

(1) Install multiple directional microphones inside or outside the video camera, fixed in different directions vertically or symmetrically with respect to the optical axis direction of the video camera, and The optical axis of the video camera is moved in the direction in which the difference between the signals based on the audio signals obtained from the pair is minimized.

(2) Install multiple directional microphones inside or outside the video camera in different directions so that the optical axis of the video camera is the directional characteristic axis of the microphone that has the maximum audio output among the microphone outputs mentioned above. move in the direction.

[Effect]

The above configurations (1) and (2) will be explained using FIGS. 9 and 10. FIG. 9 and FIG. 10 respectively show the above configuration (
L) The principle of the automatic tracking system for a video camera configured according to (2) is explained. The figure shows how a subject 901 who is speaking loudly is being tracked. 902.902', 902'' is a microphone, 9
03 is a video camera, and 904 is a disk to which a microphone is fixed. - The dotted line 905 is the optical axis of the video camera 903, and the broken line 906 is the microphone 90.
2.902' and 902'' are the respective directional axes.

Configuration (1) will be explained using FIG. 9. In FIG. 9(a), the audio level B input to the microphone 902' is higher than the audio level A of the microphone 902. In FIG. In other words, when the state is BAA.

A disc 904 and a video camera 9 fixed to the disc 904
Rotate 03 clockwise. As a result, Figure 9 (b
), the audio levels A and B from the microphones 902, 902' A=B are equal, and at this position the disc 90
4 and the video camera 903 stop, and the video camera 90
3, a subject 901 is photographed.

Configuration (2) will be explained using FIG. 10. Figure 10 (a
), three microphones 902, 902'
, 902", the microphone that obtains the maximum audio output is 902, and these microphones 902, 902"
', 902'' is in a fixed state, and the video camera 903
, the optical axis 905 is the directional axis 90 of the microphone 902.
6 so that they match, and the two match as shown in FIG. 10(b).

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. In FIG. 1, lot 102 is a microphone. These microphones 101, 10
2 each have directivity, and each directional axis is always fixed in a direction symmetrical with respect to the optical axis of the video camera. These microphones may be used as stereo microphones used for boat fishing, and the central axis of orientation thereof may be fixed in a direction that coincides with the optical axis of the video camera.

Detectors 103 and 104 extract necessary frequency components from the microphone output signals, and output voltages according to the magnitude of each microphone output. 105
is a differentiator, which determines which of the audio outputs obtained from the microphones 101 and 102 is greater or equal. The motor controller 106 rotates the motor clockwise or counterclockwise based on this determination result, and stops the motor when the respective audio outputs become equal. The motor 107 rotates the video camera itself or the optical axis of the video camera, and the microphones 101 and 102.

By doing the above, the optical axis of the video camera can always be tracked in the direction in which the sound is being emitted, and an automatic tracking system for the video camera can be realized without having to attach an oscillator to the subject as described above. can.

FIG. 2 is a front view and a side view of an automatic tracking system for a video camera constructed by the above means.

The video camera 206 and the rotating pan head 207 are connected to the video camera optical axis 204 and the aforementioned microphone L201 and microphone R20.
The two orientation axes are fixed so that their centers point in the same direction, and rotated on a fixed plate 208.

In the figure, the microphone is attached to the rotating pan head side, and if the configuration is such that the rotating pan head and video camera can be attached and detached, any video camera can be used in the system. Furthermore, if a stereo microphone is provided on the video camera side, this may be used as the audio signal source.

Another embodiment of the present invention will be described with reference to FIGS. 3 and 4.

The automatic tracking system for a video camera in the previous embodiment may cause the following problems.

1. He is constantly rotating from side to side and is restless.

2. If the response sensitivity is increased in order to respond to voices far from the system, a slight noise generated near the system will cause it to malfunction.

In this embodiment, in order to avoid these problems, a dead zone is provided in which the system does not operate even if the volume of the left and right microphones differs below a certain value, and the size of the dead zone or response sensitivity is determined by the microphone. The device determines the surrounding noise based on the average output audio level and then switches the device for use.

FIG. 3 is a block diagram of the automatic tracking system for a video camera according to this embodiment. The basic configuration is the same as the previous embodiment, but the outputs of the detectors 203 and 204 are input to an adder 206, and from the addition results, the response sensitivity and the size of the dead band are determined by the gain switch 206 and the dead band switch 207. Switch and use.

In other words, when there are various noises in the surroundings and the average level input to the microphone becomes large, the response sensitivity may be reduced,
Or increase the dead zone width.

Conversely, when the surroundings are quiet, the response sensitivity is increased or the dead band width is decreased. As a result, the above-mentioned problems can be avoided and a stable automatic tracking system for video cameras can be realized.

FIG. 4 is an example of a circuit for realizing the automatic tracking system for a video camera in this embodiment. R401 to R420 are resistors, C1 to C5 are capacitors, Ql to Q5 are transistors, Al, A2 are operational amplifiers, 01 to C4 are comparators, SW
I and SW2 are analog switches, and Vl to ■8 are power supplies. After detecting the audio signal input from the microphones 401 and 402, a summing amplifier using an operational amplifier A1;
The gain of the differential amplifier is input to the differential amplifier A2 by the operational amplifier A2, and the gain of the differential amplifier changes as SWI,2 opens and closes depending on the change in the output voltage of the summing amplifier.When the inputs from the two microphones are small, the gain becomes large, and the gain of the differential amplifier is When it is large, the gain is small. Further, if the differential amplifier output is higher than the voltage source 7, the motor controller 403 is instructed to rotate clockwise, and if it is lower than the voltage source 8, it is instructed to rotate the motor counterclockwise. In this way, the potential difference between the voltage sources 7 and V8 becomes a dead zone, so the width of the dead zone as seen from the audio signal changes depending on the magnitude of the input.

Still another embodiment of the present invention will be described using FIGS. 5 and 6.

In this embodiment, an automatic tracking system for a video camera is constructed using a microcomputer (hereinafter referred to as microcomputer), and FIG. 5 is a configuration diagram thereof, and FIG. 6 is a flowchart. In this embodiment, in addition to the above-mentioned gain switching and dead band switching to change the size of the audio signal from the microphone, the detection characteristics and filtering can be changed using a mode switch according to the purpose of use, such as party mode or monitoring mode, and the ROM A function is added to give priority to the tracking operation based on the synchronization between the audio signal stored in the input audio signal and the input audio signal.

Audio signals input from the left and right microphones 516 and 517 are compared with audio stored in the ROM 514 in advance. As a result, if it is determined that the voice is the same as the stored voice, a rotation command is given to the motor preferentially regardless of the size of the subsequent filter or dead zone. In the normal case, the filter circuit 5
05.506, the frequency characteristics and detection characteristics of the filter circuit are switched by a mode switch 518.

As an example of this mode switch, if a party mode and a monitoring mode are provided, in the former, the frequency band passing through the filter is matched to the human voice, and the response to pulseive sounds is further made slower. In addition, in monitoring mode, the frequency band that passes through the filter is set slightly wider, making the response to pulsed sounds even stronger. By doing so, tracking can be performed naturally for the purpose of use.

Also in this embodiment, the response sensitivity and dead band width are switched depending on the magnitude of the audio input from the microphone.

Still another embodiment of the present invention will be described using FIGS. 7 and 8.

In this example, the microphone is always fixed;
Only the video camera or the video camera optical axis is rotated by the sound. FIG. 7 is a front, side, and top view of the automatic tracking system for a video camera in this embodiment, and FIG.
The figure is a signal processing flowchart in this embodiment.

In this embodiment, the rotary table 706 motor is driven so that the video camera optical axis 703 coincides with the directional axis of the microphone outputting the maximum audio level. In the flowchart of FIG. 8, the variable imax is the directional axis number of the microphone that obtains the maximum audio level, and the camera optical axis is rotated by comparing imax with the optical axis position.

In addition, in this embodiment as well, more natural automatic tracking is achieved by combining the above-mentioned operation sensitivity based on the sum of microphone inputs, switching of the dead band, switching of the filter and detection characteristics using the mode switch, or priority operation for specific voices, etc. It can be a system.

〔Effect of the invention〕

According to the present invention, attaching a special oscillator etc. to the subject,
It is possible to configure an automatic tracking system for a video camera without the need for a mobile phone, and it can be applied to filming an unspecified number of people at parties, weddings, etc., and monitoring systems using video cameras. can.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIGS. 2(a) and 2(b) are front and side views showing the external shape of the automatic tracking system according to the above embodiment, and FIG. FIG. 4 is a configuration diagram showing another embodiment of the invention, and FIG. 4 is a circuit diagram showing an example of a circuit diagram for realizing the above embodiment. FIG. 5 is a block diagram of a microcomputer showing another embodiment of the present invention, and FIG. 6 is an operation flowchart thereof. FIG. 7 is a front view and a side view showing the outline of an automatic tracking system according to another embodiment of the present invention, and FIG. 8 is an operation flowchart thereof. FIG. 9 and FIG. 10 are block diagrams schematically showing the automatic tracking system of the present invention. 101, 102...Microphones 103, 104...Detector 105...Differentiator 106...Motor controller No. 1? Figure (α) I! l 疋 喋 (b) Fig. Fig.

Claims (1)

[Claims] 1. In an automatic tracking device for a video camera that automatically tracks the optical axis of the video camera toward a subject, a receiver for a tracking signal emitted from the subject itself or from the direction of the subject is configured such that the maximum sensitivity of the receiver is A plurality of devices are arranged so that the obtained directional axes are symmetrical at a certain angle on a certain plane with respect to the optical axis of the video camera, and the difference in the amount of signals input to the symmetrically arranged receivers is reduced. An automatic tracking device for a video camera, characterized in that the optical axis of the video camera is moved in a direction. 2. A dead zone for tracking operation is established for differences in signal amounts input to symmetrical receivers, and tracking operations are performed only when the difference in signal amounts exceeds the dead zone and exceeds a certain value. An automatic tracking device for a video camera according to claim 1. 3. The automatic tracking device for a video camera according to claim 2, wherein the size of the dead zone is switched according to the size of the signal input to each receiver. 4. In an automatic tracking device for a video camera that automatically tracks the optical axis of the video camera toward the subject, the first and second microphones that receive audio emitted from the subject are arranged so that their respective directional axes are aligned with the optical axis of the video camera. the optical axis of the video camera in a direction in which the magnitudes of the audio signals received by the first and second microphones have a predetermined relationship. An automatic tracking device for a video camera that moves. 5. In an automatic tracking device for a video camera that automatically tracks the optical axis of the video camera toward the subject in response to the sound emitted from the subject, depending on the environment in which the automatic tracking device is used or the purpose for which it is used, An automatic tracking device for a video camera characterized by switching filter characteristics for detecting or filtering the audio signal, or an automatic tracking device for a video camera equipped with a switch for changing the filter characteristics.