JPH07312700A - Television camera system - Google Patents

Abstract

PURPOSE:To match vertical synchronization between camera with field synchronization by providing a power unit with an external synchronization superposition part and providing the camera with a signal separation part and a timing control part. CONSTITUTION:The vertical synchronizing signal and a field identification signal of external synchronization are transmitted from the external synchronization superposition part 6 of the power unit 3 to respective television camera 1 via a coaxial cable 2. Each camera 1 samples by separating transmitted vertical synchronizing signal and field identification signal by the signal separation part 14, and the vertical synchronization and the field synchronization can be obtained by the timing control part 15 based on the vertical synchronizing signal and the field identification signal of external synchronization. In this way, it is possible to perform not only the matching of the vertical synchronization but that of the field of each camera 1 and to prevent the irregularity of an image according to the noncoincidence of the field when the video signal of each camera 1 is displayed on a monitor screen by screen-dividing/ synthesizing, etc., which improves performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television camera device having a plurality of cameras mainly used for surveillance and crime prevention.

[0002]

2. Description of the Related Art Conventionally, this kind of television camera device such as surveillance equipment and crime prevention equipment has been designed to simplify installation work.
There is a one-cable system that uses one coaxial cable for each power supply and signal transmission to connect each TV camera to each power supply device. This conventional one-cable television camera device will be described with reference to FIGS. 2 and 7 corresponding to the embodiment of the present invention.

As shown in both figures, for example, a plurality of television cameras 1 # 1 to #n arranged in various places in the surveillance area are
Each camera is connected to each power supply device 3 via a power feeding and signal transmission coaxial cable 2, and this power supply device 3 is used except when the camera 1 serves as a reference for external synchronization.
An external synchronization superposing unit 6 is provided together with the power feeding unit 4 and the video output unit 5. 2 shows a case where the # 1 camera 1 serves as a reference for external synchronization, and FIG. 7 shows a case where none of the cameras 1 serves as a reference for external synchronization.

Then, the external synchronizing vertical synchronizing signal of the external synchronizing superposing section 6 is superposed on the DC power source of the power feeding section 4, and the signal formed by this superposition is transmitted to the camera 1 via the cable 2. By this transmission, the DC power for driving is supplied to the camera 1, and the video signal (composite video signal) of the interlaced scanning of the captured image is formed by the vertical synchronization of the external synchronization by the synchronization control based on the vertical synchronization signal of the external synchronization. .

Then, the video signal or the like is transmitted to the power supply device 3 via the cable 2, and the video signal is transmitted from the video output terminal 5'such as the BNC terminal of the video output unit 5 via the connection cable 7 for each power supply device 3. For example, it is sent to the switcher 8 of the monitor console.

The switcher 8 switches one or a plurality of video signals of each camera 1 sequentially by video processing using a memory based on automatic or manual switching of monitor screens and division operation, and screen division / combination. It is supplied to the monitor television 9, and the television 9 displays a monitor screen based on the photographing output of each camera 1. At this time, since the vertical synchronization of each camera 1 is matched, the synchronization disorder of the screen when the video signals of each camera 1 are sequentially switched and displayed is prevented.

[0007]

In the case of the conventional one-cable type television camera device, although the vertical synchronizations of the cameras 1 match, the fields of the cameras 1 are not synchronized. When the fields of the cameras 1 do not coincide with each other, and when the video signals of the cameras 1 are displayed on the monitor television 9 by, for example, four-division composition by screen division composition, one scanning line (line) is displayed between the cameras 1. ) There is a problem that it becomes unsightly due to a degree of deviation. It is an object of the present invention to match vertical synchronization and field synchronization between television cameras.

[0008]

In order to achieve the above object, in the television camera device of the present invention, an external synchronizing vertical synchronizing signal and a field identification signal are transmitted to a power source device of the television camera through a coaxial cable. Equipped with an external sync superposition unit that transmits to the TV camera, the TV camera controls the vertical sync and field sync with the signal separation unit that separates and extracts the vertical sync signal and field identification signal of the coaxial cable. And a timing control unit for controlling the timing.

[0009]

In the case of the television camera device of the present invention configured as described above, the external synchronizing vertical synchronizing signal and the field identification signal are transmitted to the respective television cameras from the external synchronizing portion of each power supply device through the coaxial cable. To be done.

Then, each television camera separates and extracts the transmitted vertical synchronizing signal and field identification signal by a signal separating unit, and a timing control unit separates vertical synchronizing signal and field synchronizing signal based on the external synchronizing vertical synchronizing signal and field identifying signal. Take

Therefore, the vertical synchronization and the field synchronization of each TV camera are matched, and the disturbance of the screen due to the mismatch of the fields when the video signals of each TV camera are divided into screens and displayed on the monitor screen is prevented. .

[0012]

EXAMPLES Examples will be described with reference to FIGS. 1 to 7. (First Embodiment) First, referring to FIGS.
Will be described with reference to. FIG. 2 shows a case where the # 1 camera is used as a reference for external synchronization, and vertical synchronization of this camera 1 and vertical synchronization and field synchronization of other cameras 1 are established with reference to the field. When the video signal is transmitted to the power supply device 3 through the cable 2, the sync separation circuit 10 for external synchronization of the power supply device 3 causes the video signal shown in FIG.
The composite sync signal C / SYNC shown in (a) is separated and extracted.

Then, the composite sync signal C.SYNC is transmitted to the power supply device 3 of each camera 1 after # 2 via the connection cable 11 for external synchronization. The power supply device 3 of the camera 1 after # 2 is different from the conventional device in that the external synchronization superimposing unit 6 causes the composite synchronization signal C / SY of the connection cable 11 to be generated.
This is the point of forming the vertical synchronization signal and the field identification signal for external synchronization from the NC and transmitting them to the respective cameras 1 via the cable 2.

That is, the external synchronization superposition section 6 is constructed as shown in FIG. 1, and the composite synchronization signal C.
SYNC is supplied to the vertical sync separation circuit 6a and the field identification signal generation circuit 6b. 1 shows the camera 1 of # 2 and its power supply device 3, and the cameras 1 after # 3 and their power supply devices 3 have the same configuration as that of FIG.

Then, the sync separation circuit 6a separates and extracts the vertical sync signal VD shown in FIG. 3B, and the generation circuit 6b forms the field identification signal FI shown in FIG. 3C having a double cycle of the vertical sync signal VD. To do.

Further, the vertical synchronizing signal VD and the field identification signal FI are supplied to the waveform shaping circuits 6c and 6d for waveform shaping, and are synchronized with the trailing edge of the synchronizing signal VD at the leading edge of the field in FIGS. ) Vertical sync signal vd for superimposed transmission of positive polarity identical pulse waveform, field identification signal fi
Is formed.

At this time, the first field (odd field) is F ₁ , and the second field (even field) is F _2.
Then, the vertical synchronizing signal vd is formed in each field in synchronization with the falling edge of the vertical synchronizing signal VD in FIG. 4A as shown in FIG. 4B, and the field identification signal fi depends on the presence or absence of this signal. In order to enable field identification, it is formed for each first field F ₁ in synchronism with the rising edge of the field identification signal FI shown in FIG. 7C as shown in FIG.

Further, the vertical synchronizing signal vd and the field identification signal fi are supplied to an amplitude control circuit 6e formed by a variable gain amplifier, an adder or a multiplier, and this control circuit 6e controls the gain of the field identification signal fi or the like. The vertical synchronization signal vd and the field identification signal fi are added and combined.

By this addition synthesis, a positive pulse signal whose amplitude (level) becomes large (high level) in the first field F ₁ and becomes small (low level) in the second field F ₂ is obtained. It is formed as a pulse signal for external synchronization. Then, this positive-polarity externally synchronized pulse signal is superimposed on the DC power source of the power feeding unit 4 and transmitted to the camera 1 via the cable 2.

At this time, since the composite video signal of the captured image of the video processing unit 12 of the camera 1 is transmitted to the video output unit 5 of the power supply device 3 via the cable 2, the pulse signal of the external synchronization of the amplitude control circuit 6 is transmitted. Is actually superimposed on the composite video signal of the DC power supply and the imaging output.

In consideration of the negative polarity of the sync signal of the composite video signal, the vertical sync signal vd and the field identification signal fi are formed in the positive polarity in order to facilitate signal separation and the like. Camera 1 as a sex pulse signal
Be transmitted to.

Further, the field identification signal fi is not a code signal but a pulse signal because the vertical synchronizing signal v
This is because it is the simplest means for adding field information to the external synchronization signal without affecting the phase information of d, the circuit configuration thereof is extremely simple, and the signal separation is easy.

Then, the positive external synchronizing pulse signal of the amplitude control circuit 6e is superimposed on the composite video signal of the camera 1, so that the signal of the cable 2 becomes as shown in FIG. 5 (a).

The solid line (a) in FIG. 4A indicates a pulse signal for external synchronization of the first field F _{1 in which} the field identification signal fi exists, and the solid line a indicates external synchronization of the second field F _{2 in which} the field identification signal fi does not exist. The pulse signal, c shows the vertical synchronizing signal portion of the composite video signal of the camera 1.

Further, when the vertical sync signal portion c of the first and second fields F ₁ and F ₂ of FIG. 5A is enlarged, it becomes as shown in FIG. 5B. And FIG. 5 (a), (b)
As is clear from the above, when synchronization is achieved, the pulse signal for external synchronization is superimposed on the portion of the vertical blanking period of the composite video signal and does not affect the video output of the camera 1.

Next, the camera 1 after # 2, in which the pulse signal of the external synchronization of the amplitude control circuit 6e is transmitted via the cable 2, is different from the conventional camera, as shown in FIG. Signal separation unit 1 together with power supply circuit unit 13 and the like
4, the timing control unit 15 is provided.

The DC power transmitted from the power supply unit 4 via the cable 2 is supplied from the power supply circuit unit 13 to each unit of the camera 1, and the camera 1 operates to generate a composite video signal of the photographed image in the image processing unit. It is output from 12 to the cable 2.

Further, the amplitude control circuit 6 via the cable 2
The externally synchronized pulse signal e is supplied to the vertical sync separation circuit 14a and the field identification signal separation circuit 14b of the signal separation unit 14.

The sync separation circuit 14a is shown in FIG.
As shown in, the vertical synchronizing signal vd is reproduced for each transmission input of the pulse signal of the positive polarity of the external synchronizing, and the vertical synchronizing signal vd is separated and extracted.

Further, the identification signal separation circuit 14b discriminates the amplitude of the positive pulse signal of the external synchronization, and the field identification signal fi is superposed on the first field F ₁ to have a large amplitude.
6 only at the timing of the positive pulse signal.
The field identification signal fi shown in (b) is reproduced and separated and extracted.

Further, in order to prevent the hunting operation of the PLL control of the timing control section 15, the field identification signal fi of the identification signal separation circuit 14b is delayed by the delay circuit 14c for a time period τ of about 1/2 field, and the first field F. The field identification signal fi 'of FIG. 6 (c), which is phase-shifted to the center of ₁ , is formed.

On the other hand, the timing control unit 15 controls the voltage controlled oscillator 15a by PLL, and based on the output of the oscillator 15a, various signals of the camera 1 such as the composite sync signal C / SYNC of the video processing unit 12 are generated by the timing signal generation circuit 15b. Generates timing signals.

The vertical synchronizing signal vd is used as the timing signal.
And an internal identification signal int.fi corresponding to the field identification signal fi, which is formed based on the composite synchronizing signal C.SYNC.

At this time, the synchronizing signal int.vd is a positive pulse signal of FIG. 6 (d) which is generated in synchronization with the leading edge of each field of the composite synchronizing signal C.SYNC, like the vertical synchronizing signal vd. The identification signal int · fi is shown in FIG.
Similar to the identification signal FI of FIG. 4C, the level is inverted field by field and becomes high level in the first field.
It is a positive sync signal of (e).

Then, the field identification signals fi ', in
t • fi is the detection circuit 15d via the AND gate 15c.
The output signal of the detection circuit 15d becomes high level when both the identification signals fi 'and int.fi become high level at the same time when the odd and even of the field of external synchronization coincide with the camera 1.

Further, the vertical sync signal vd of the sync separation circuit 14a and the output signal of the detection circuit 15d are AND gate 1.
The AND gate 15e is turned on and the vertical synchronizing signal vd is supplied to the phase comparator 15f only when the output signal of the detection circuit 15d becomes high level.

Then, the phase comparator 15f compares the output signal of the AND gate 15e with the internal vertical synchronizing signal int.vd to form a signal having a phase difference between the two signals. This signal is smoothed by a loop filter (low-pass filter) 15g to form a control voltage signal, and the oscillator 1 is arranged so that both synchronizing signals vd, int · vd coincide with each other.
The oscillation frequency of 5a is PLL controlled.

By this PLL control, the respective signals of FIG. 6 are synchronized, and by the PLL control of the first field F ₁ , vertical synchronization and frame synchronization of the composite synchronization signal C / SYNC of the camera 1 output from the timing generation circuit 15b are achieved. It is established by an external synchronization vertical synchronization signal vd and a frame identification signal fi.

Therefore, the vertical synchronization and field of each camera 1 after # 2 coincides with the vertical synchronization and field of the camera 1 of # 1, and in particular, by the coincidence of field synchronization between each camera 1, for example, the monitor television 9 In addition, when the video signal of each camera 1 is displayed by the screen division synthesis such as the 4-division synthesis, the shift of the scanning line between the cameras 1 is prevented.

The field identification signal fi 'delayed by τ from the field identification signal fi is used for the field synchronization P.
Since the LL control is performed, so-called out-of-synchronization does not occur even if the field identification signal fi changes, and the operation is stable.
Further, R in FIGS. 1 and 2 indicates a resistance, and C indicates a capacitor.

(Other Embodiments) Next, other embodiments will be described with reference to FIG. FIG. 7 shows a case where the external synchronization signal generator 16 separate from each camera 1 is used to control the synchronization of each camera 1 with reference to the synchronization of each camera 1. The difference from FIG. The power supply 3 is also shown in FIG.
Each of the cameras 1 from the external synchronization signal generator 16 is connected to the external synchronization signal generator 16 or via the connection cable 17 of each power supply device 3.
This is the point that the power supply device 3 is supplied with the composite sync signal C.SYNC similar to the output signal of the sync separation circuit 10 of FIG. In this case, the vertical synchronization and frame synchronization of each camera including the # 1 camera 1 are externally synchronized to obtain the same effect as that of the first embodiment.

The configuration of each part of the camera 1 and the power supply device 3 is not limited to the configurations of the above-described embodiments, but the vertical sync signal vd, the signal shape of the field identification signal fi,
The polarity and the like are not limited to those in the above-mentioned examples. Further, it is needless to say that the present invention can be applied to the case of transmitting an audio signal and the like together with a video signal from the camera 1 to the power supply device 3 via the cable 2.

Furthermore, in both of the above-described embodiments, the basic configuration in which one power supply device 3 is provided for each camera 1 has been described, but the number of cameras 1 is large, and one power supply device is provided for each of a plurality of cameras. Of course, it can be applied to the case of the configuration and the like. The present invention can be applied to one-cable television camera devices for various purposes.

[0044]

Since the present invention is configured as described above, it has the following effects. Power supply 3
The external synchronizing vertical synchronizing signal and the field identification signal are transmitted from the external synchronizing superposing section 6 to each television camera 1 through the coaxial cable 2, and the vertical synchronizing signal and the field identification signal transmitted by each camera 1 are separated. The unit 14 separates and extracts, and the timing control unit 15 establishes vertical synchronization and field synchronization based on the external synchronization vertical synchronization signal and field identification signal. Therefore, not only the vertical synchronization of each camera 1 but also the field can be matched. The screen disturbance due to field inconsistency such as when the video signals of the cameras 1 are divided into screens and displayed on the monitor screen is prevented, and the performance is significantly improved.

[Brief description of drawings]

FIG. 1 is a detailed block diagram of a part of an embodiment of a television camera device of the present invention.

FIG. 2 is a block diagram of the overall configuration of an embodiment of the present invention.

3A to 3E are first timing charts for explaining the operation of the external synchronization superposing unit in FIG.

4A to 4D are second timing charts for explaining the operation of the external synchronization superposing unit in FIG.

5 (a) and 5 (b) are signal waveform diagrams of the coaxial cable of FIG.

6A to 6E are timing charts for explaining the operation of the signal separation unit and the timing control unit in FIG.

FIG. 7 is a block diagram of another embodiment of the present invention.

[Explanation of symbols]

 1 TV camera 2 coaxial cable 3 power supply device 6 external synchronization superimposing unit 14 signal separating unit 15 timing control unit

Claims (1)

[Claims] 1. A plurality of television cameras and a power supply device for each television camera are connected by one coaxial cable for each camera that superimposes power and signals and multiplex-transmits, and the power supply device is connected to the cameras. Power to
A television camera device for externally outputting the video output of the camera from the power supply device, wherein the power supply device is provided with an external synchronization superposition unit for transmitting an external synchronization vertical synchronization signal and a field identification signal to the camera via the cable. The camera is provided with a signal separation unit that separates and extracts the vertical synchronization signal and the field identification signal of the cable, and a timing control unit that controls vertical synchronization and field synchronization by the vertical synchronization signal and the field identification signal. A television camera device characterized in that