JPH05130446A - Monitor camera apparatus - Google Patents

Abstract

PURPOSE:To shorten synchronization lock time by providing a circuit applying synchronization superimposition of a field reference signal onto an external reference signal to a power supply section and providing a circuit synchronizing a video camera to the field reference signal to a camera section. CONSTITUTION:An external synchronizing circuit 15 in a power supply section 3 synchronizes a field reference signal generating circuit 14 with an externally inputted reference signal. A camera section 1 separates a field reference signal by using a reference signal separate circuit 8 and a field synchronizing circuit 7 synchronizes a video camera 4. Then a video signal obtained by the video camera 4 is superimposed onto a transmission cable section 3 by a video signal superimposing circuit 5 and the result is sent to the power supply section. The power supply section 3 separates the sent video signal with a video signal separation circuit 11 and a video signal output circuit 12 outputs the result externally. Thus, the video signal in which the external reference signal, the phase of a vertical synchronizing signal and a field are made coincident is obtained, the synchronization lock time is reduced and the video signal after locking is made stable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply superimposition type surveillance camera device for matching the phase and field of a vertical synchronizing signal of the camera.

[0002]

2. Description of the Related Art In a conventional device, consideration has been given to the phase matching of vertical synchronizing signals.

Incidentally, as a device related to this kind of device, there is, for example, JP-A-1-36284.

[0004]

In the above-mentioned prior art, no consideration is given to the coincidence of fields, and there is a problem that the monitor screen is disturbed at the time of switching by the switcher and the image quality is deteriorated due to the crosstalk of the horizontal synchronizing signal. was there.

An object of the present invention is to make the phases and fields of the vertical synchronizing signals of a plurality of cameras coincide with each other so as to eliminate the disturbance of the monitor screen when the cameras are switched by the switcher and suppress the deterioration of the image quality due to crosstalk.

Another object of the present invention is to match the phase and field of the vertical synchronizing signal of the present monitoring camera apparatus with those of the external reference signal source, the present monitoring camera apparatus or another camera apparatus.

Another object is to shorten the synchronization pull-in time and to stabilize after the pull-in.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the following is performed.

According to a first aspect of the present invention, in the single power supply superimposing camera device, the power supply unit is provided with a circuit for synchronizing and superimposing the field reference signal with the external reference signal. Further, the camera unit is provided with a circuit for synchronizing the video camera with the superimposed field reference signal.

According to a second aspect of the present invention, in a device including a plurality of power superimposing cameras, the power supply unit is provided with a circuit for superimposing a single field reference signal on each transmission cable unit. Then, each camera unit is provided with a circuit for synchronizing the video camera with the superimposed field reference signal.

Further, according to a third aspect, an external synchronizing circuit is provided in the single field reference signal generating circuit in the power supply section of the surveillance camera device according to the second aspect.

Further, in order to shorten the synchronization pull-in time and to stabilize after the pull-in, the reset circuit operates when the phase of the field synchronization circuit of the camera unit is greatly deviated, and the phase lock is performed when it is close. The loop circuit operates.

[0013]

The surveillance camera apparatus according to the first aspect operates as follows.

The external synchronizing circuit in the power supply section synchronizes the field reference signal generating circuit with the externally input reference signal. The field reference signal obtained from this is superimposed on the transmission cable section by the reference signal superimposing circuit and sent to the camera section. In the camera section, this field reference signal is separated by the reference signal separation circuit, and the video camera is synchronized by the field synchronization circuit. The video signal obtained from the video camera is superimposed on the transmission cable section by the video signal superimposing circuit and sent to the power supply section. In the power supply unit, the transmitted video signal is separated by the video signal separation circuit and output from the video signal output circuit to the outside. Therefore, it is possible to obtain a video signal in which the phase and the field of vertical synchronization match the external reference signal.

Further, in the second aspect of the present invention, it operates as follows. The field reference signal generated by the single field reference signal generation circuit in the power supply unit is sent to the plurality of reference signal superposition circuits. Each reference signal superimposing circuit superimposes the field reference signal on the corresponding transmission cable section and transmits it to each camera section. In each camera unit, the field reference signal is separated in the same manner as described above, and each video camera is synchronized. Then, the video signal of each video camera is superimposed on the transmission cable section by the corresponding video signal superimposing circuit and sent to the power supply section. In the power supply unit, each transmitted video signal is output through each video signal separation circuit and each video signal output circuit. Therefore, the output video signals have the same vertical synchronization phase and field.

Further, in the present invention, the external synchronizing circuit in the power supply unit synchronizes the field reference signal generating circuit with the external reference signal. Then, the other parts have the same function as in claim 2. Therefore, the vertical synchronization phase and field of each video signal match that of the external reference signal.

In the fourth aspect, the operation is as follows. The field synchronization circuit of the camera section compares the phase of the field reference signal sent from the power supply section with the phase of the field signal of the video camera. When this phase difference is larger than a predetermined value, the field synchronization circuit is reset with the phase of the field reference signal. If it is smaller than the specified value,
The field synchronization circuit is operated in PLL.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of claim 1 will be described with reference to FIG.
The surveillance camera device of the present invention includes a camera unit 1, a transmission cable unit 2, and a power supply unit 3. In the power supply unit 3, the power converted from AC to DC by the DC power supply circuit 10 is superimposed on the transmission cable unit 2 by the DC power supply superimposing circuit 9, and the camera unit 1
Sent to. The electric power sent to the camera unit 1 is separated by the DC power supply separation circuit 6 and supplied to each circuit in the camera unit 1. A video signal captured by the video camera 4 is superimposed on the transmission cable section 2 by the video signal superimposing circuit 5 and sent to the power supply section 3. Then, this video signal is separated by the video signal separation circuit 11 and output from the video signal output circuit 12 to an external device such as a monitor.

In order to synchronize this video signal with an external signal such as another camera device or a reference signal source, each circuit operates as follows. First, the external reference signal is input to the power supply unit 3. As the external reference signal, a video signal, a composite sync signal,
Horizontal / vertical sync signals are possible. External synchronization circuit 15
Are the reference signal and the field reference signal generation circuit 14
Field reference signal generation circuit 14 to match the vertical synchronization phase and field of the field reference signal
To control. The obtained field reference signal is superimposed on the transmission cable section 2 by the reference signal superimposing circuit 13 and sent to the camera section 3. In the camera unit 3, the reference signal separation circuit 8
The field reference signal is separated by. The field synchronization circuit 7 synchronizes the video camera 4 with this field reference signal. Therefore, the present surveillance camera device can obtain a video signal in which the phase and field of vertical synchronization match the external reference signal.

The field reference generating circuit 1 shown in FIG.
4 shows an example of a field reference signal generated by No. 4. 16 in the figure
Is an example of generating a pulse for each frame. 1 in the figure
7 is an example in which the pulse width is changed for each field. In the figure, 18 is an example in which the pulse level is changed for each field. These reference signals are always constant with reference to either the odd field or the even field, and are matched with the same field when synchronizing with the camera unit 1.

Further, the negative pulse of each example can be considered.

According to the present embodiment, it is possible to obtain a video signal in which the phases and fields of vertical synchronization are matched by synchronizing with any desired number of the monitoring camera devices.

An embodiment of claim 2 will be described with reference to FIG.

The surveillance camera apparatus of the present invention comprises n camera units 1-n, n transmission cable units 2-n, and a power supply unit 3.
Composed of. The individual camera section 1-n and the transmission cable section 2-n are the same as those in the above embodiment. Also,
In the power supply unit 3, the power converted from AC to DC by the single DC power supply circuit 10 is sent to the n DC power supply superposition circuits 9-n and superposed on each transmission cable unit 2-n to each camera unit 1-n. Sent.

The field reference signal generated by the field reference signal generation circuit 14 is composed of n reference signal superposition circuits 1.
3-n superimposes on each transmission cable section 2-n and sends to each camera section 1-n. Then, in each of the camera units 1-n, the synchronization is performed as in the above-described embodiment. Therefore, the video signal of each camera unit 1-n has the same vertical synchronization phase and field.

According to this embodiment, it is possible to easily synchronize with a predetermined number of camera units.

An embodiment of claim 3 will be described with reference to FIG.

According to the present invention, an external synchronizing circuit 15 is added to the device of the second embodiment. External synchronization circuit 15
Synchronizes the field signal generating circuit 14 with the external synchronizing signal. The other circuits operate similarly. This allows
A large number of camera units can be easily synchronized with the external reference signal.

An embodiment of claim 4 will be described with reference to FIGS. FIG. 5 shows an embodiment of the synchronizing circuit 7. FIG. 6 shows the pulse phase of this embodiment. Field signal 26
Are made on the basis of the same field as the field reference signal 16. The field gate pulse 27 is formed so as to surround the field signal 26.

Reference numeral 16 in FIG. 5 is a field reference signal 16 separated by the reference signal separation circuit 8. This reference signal includes a PLL circuit including a phase comparison circuit 20, a low pass filter 21, and a voltage control transmission circuit 22, and an AND circuit 1
9, sent to the reset circuit composed of the vertical reset circuit 23.

Here, the clock pulse generated in the voltage control transmission circuit 22 is sent to the counter circuit 24 and various synchronizing signals are generated. Various sync signals are sent to the video camera 4 via the buffer circuit 25. Further, the field signal 26 therein is sent to the phase comparison circuit 20 and compared in phase with the field reference signal 16. Then, the phase difference voltage is sent to the low pass filter 21 to remove ripples, and then the voltage controlled oscillator circuit 22 is controlled.

The AND circuit 19 also generates a reset pulse 28 when the field reference signal 16 and the reset gate pulse 27 are not in a predetermined phase relationship. The reset pulse 28 is sent to the vertical reset circuit 23 to reset the counter circuit 24 to an odd or even field. This operation is repeated until the fields match. According to the present invention, the pull-in time can be shortened.

[0033]

According to the present invention, the phases and fields of the vertical synchronizing signals of a plurality of power superimposing cameras can be matched. Therefore, it is possible to prevent the disturbance of the monitor screen at the time of switching by the switcher and the deterioration of the image quality due to the crosstalk of the horizontal synchronizing signal.

Further, according to the invention of claim 2, an external reference signal generator is not required. In addition, according to the invention of claim 4, it is possible to shorten the synchronization pull-in time of the camera unit and to stabilize after the pull-in.

[Brief description of drawings]

1 is a block diagram of an embodiment of claim 1. FIG.

FIG. 2 is a diagram showing an example of a field reference signal.

FIG. 3 is a block diagram of an embodiment of claim 2;

FIG. 4 is a block diagram of an embodiment of claim 3;

FIG. 5 is a block diagram of a field synchronization circuit according to claim 4;

FIG. 6 is a waveform diagram of each part of FIG.

[Explanation of symbols]

 1, 1-1, 1-n ... Camera part, 2, 2-1 and 2-n ... Transmission cable part, 3, 3-1 and 3-n ... Power supply part, 4, 4-1, 4-n ... Video camera, 5,5-1,5-n ... Video signal superimposing circuit, 6,6-1,6-n ... DC power supply separating circuit, 7,7-1,7-n ... Field synchronizing circuit, 8,8 -1,8-n ... Reference signal separation circuit, 9, 9-1, 9-n ... DC power supply superimposing circuit, 10 ... DC power supply circuit, 11, 11-1, 11-n ... Video signal separation circuit 12, 12-1, 12-n ... Video signal output circuit, 13, 13-1, 13-n ... Reference signal superimposing circuit, 14 ... Field reference signal generating circuit, 15 ... External synchronizing circuit, 19 ... AND circuit, 20 ... Phase Comparator circuit, 21 ... Low-pass filter, 22 ... Voltage controlled oscillator circuit, 23 ... Vertical reset circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayoshi Masayoshi 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Stock Company, Hitachi Image Information Systems (72) Koji Tanno 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Hitachi Image Information System

Claims (4)

[Claims] 1. A camera unit comprising a video camera, a video signal superimposing circuit and a DC power supply separating circuit, a power supply unit comprising a DC power supply circuit, a DC power superimposing circuit, a video signal separating circuit and a video signal output circuit, In a surveillance camera device comprising a video signal superimposed from a camera section and a transmission cable section transmitting a DC power superimposed from the power source section, a field reference signal generating circuit and the field reference signal generating circuit are inputted from the outside. An external synchronization circuit for synchronizing with a reference signal and a reference signal superimposing circuit for superimposing a field reference signal on the transmission cable section are provided in the power supply section, and a reference signal separating circuit for separating the superposed field reference signal from the transmission cable section. And having a field synchronization circuit in the camera unit for synchronizing the video camera with a field reference signal. Surveillance camera apparatus according to symptoms. 2. A plurality of camera parts according to claim 1, a same number of transmission cable parts corresponding to the camera parts, and a same number of DC power supply superimposing circuits and video signal separating circuits according to claim 1 corresponding to the camera parts. A video signal output circuit, a reference signal superimposing circuit, a single DC power supply circuit for supplying electric power to each of the DC power supply superimposing circuits, and a single field reference signal generating circuit for transmitting a field reference signal to each of the reference signal superimposing circuits. A surveillance camera device comprising a power supply unit. 3. The surveillance camera apparatus according to claim 2, further comprising an external synchronizing circuit for synchronizing a field reference signal generating circuit in the power supply unit with a reference signal input from the outside. 4. A surveillance camera apparatus according to claim 1, wherein the field synchronization circuit in the camera section comprises a reset circuit and a phase locked loop circuit.