JPH04287488A - Cctv system - Google Patents

Abstract

PURPOSE:To automatically adjust the horizontal synchronization between camer as of the CCTV system. CONSTITUTION:A video signal from each camera of the CCTV system is received, the signal from one camera is used as a reference signal, a 1st synchronizing separator section 10 separates a horizontal synchronizing signal of the video signal from the reference camera, a 2nd synchronizing separator section 11 separates a horizontal synchronizing signal of the video signal from other synchronized camera and a phase comparator section 12 detects a phase shift of the separated horizontal synchronizing signal. A pulse conversion section 13 and a pulse level control section 14 generate a control pulse in response to the detected deviation of the horizontal phase, adjust the level of the control pulse, and a synchronization coupling section 15 and a mix section 16 superimpose the control level to a signal for a horizontal blanking period of the input video signal and the result is transferred to the synchronized camera. A pulse separator section 19 of the synchronized camera separates the control pulse superimposed on an output video signal for the horizontal blanking period and a synchronization phase adjustment section 22 adjusts automatically the horizontal phase of the output video signal.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is applicable to CCTV (CTV), which is used for monitoring a predetermined area or area (for example, a bank or an amusement center).
Losed Circuit Television
n) System, more specifically, it relates to a CCTV system that automatically adjusts the synchronization of a plurality of TTCV cameras placed in a predetermined area or region.

0002

[Conventional example] Conventionally, this type of CCTV system includes, for example, a plurality of CCTV cameras (hereinafter referred to as cameras) arranged at predetermined positions in a monitoring area, a controller device that switches video signals from these cameras, and a controller device that switches video signals from these cameras. The camera is equipped with a monitor device that displays images of the monitored area and the like on a screen using switched video signals, and the camera and the controller device are connected by cables, and the controller device and the monitor device are respectively connected by cables.

By the way, in order to switch images from a plurality of cameras and display them on a monitor device, it is necessary to horizontally synchronize the video signals from the cameras. Therefore,
For example, as shown in FIG. 2, each camera is equipped with a phase adjustment circuit 2 for adjusting the horizontal phase of the video signal when the signal from the image sensor is processed by the processing unit 1 into a video signal. is being used. The phase adjustment circuit 2 controls, for example, an oscillation circuit 3 that generates a clock for the process section 1 in accordance with the phase adjustment, and adjusts the horizontal phase of the video signal.

[0004] Furthermore, the length of the cable connecting each camera and the controller device varies depending on the installation location of the CCTV system, and the horizontal phase shift of the video signal from each camera varies depending on the length of the cable. Each camera is equipped with an internal volume 4 or external volume 5 for controlling the phase adjustment circuit 2, and the horizontal phase shift can be adjusted using the internal volume 4 or external volume 5. There is.

[0005]

[Problem to be solved by the invention] However, the above CCTV
The system has the problem that it is necessary to adjust the horizontal phase shift for each camera, and furthermore, the phase shift must be adjusted by manually operating the internal volume 4 or the external volume 5.

The present invention has been made in view of the above problems, and its purpose is to provide a CCTV that can automatically adjust the horizontal phase of video signals from each camera.
system.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention connects a plurality of CCTV cameras to at least one monitor device via a controller device, switches video signals from the CCTV cameras, Alternatively, in a CCTV system that simultaneously outputs to a monitor device, the controller device uses one of the CCTV cameras as a reference, and synchronizes the synchronization signal of the video signals from this reference CCTV camera and other synchronized CCTV cameras. A pulse generating means for generating a control pulse according to a phase shift, and a reference CCT by superimposing this control pulse on a horizontal blanking period of a video signal.
Superimposing means for outputting to a CCTV camera other than the V camera;
pulse filter means for removing control pulses superimposed on video signals from each of the CCTV cameras; each camera includes pulse separation means for demodulating control pulses from the controller; Each of the above CCTs is provided with a phase adjustment means for adjusting the horizontal phase shift of the output signal accordingly.
The gist is that the horizontal phase of the video signal from the V camera is automatically adjusted.

[0008]

[Operation] With the above configuration, when switching the video signals from each CCTV camera and displaying the images from each CCTV camera on the monitor device, the controller device uses one of the CCTV cameras as a reference, and the other C of
A CTV camera is synchronized, and the horizontal synchronization signal of the video signal from the reference CCTV camera and other synchronized CCTs are synchronized.
The phase of the video signal from the V camera with respect to the horizontal synchronization signal is detected. Control pulses corresponding to this detected phase shift are generated, and these control pulses are superimposed on the horizontal blanking period of the video signal from each synchronized CCTV camera.
transferred to the camera.

In each synchronized CCTV camera, its transfer control pulse is separated, and the phase shift of the horizontal synchronization signal of the output video signal is automatically adjusted in accordance with the separated control pulse. Therefore, the C
When installing a CTV system, there is no need to adjust the horizontal phase of each CCTV camera, and the horizontal phase does not need to be adjusted each time depending on the length of the cable connecting each CCTV camera.

0010

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. In addition, in the figure, the same parts as in FIG. 2 are given the same reference numerals, and redundant explanation will be omitted. In FIG. 1, a controller device 6 of a CCTV system receives video signals from a plurality of CCTV cameras (hereinafter referred to as cameras) 7 and 8, and branches a buffer unit that branches a video signal from a camera 7 that serves as a reference. 9, a first synchronization separation unit 10 that separates the horizontal synchronization signal of this branched video signal, and a second synchronization unit that separates the horizontal synchronization signal of the video signal from the synchronized camera 8 other than the reference camera 7. a separation section 11; a phase comparison section 12 that compares the horizontal synchronization signal separated by the first synchronization separation section 10 and the horizontal synchronization signal separated by the second synchronization separation section 11 to detect a horizontal phase shift; a pulse converter 13 that generates a control pulse according to the detected phase shift;
A pulse level control unit 14 that sets this control pulse to a level that can be superimposed on the horizontal blanking period of an input video signal, a synchronization coupling unit 15 that synchronizes this level-controlled control pulse with the horizontal blanking period, and a synchronization unit 15 that synchronizes this level-controlled control pulse with the horizontal blanking period. a mixer 16 that superimposes the control pulses on the video signal from the camera 8; and a pulse filter 1 that removes the control pulses included in the video signal that has passed through the mixer circuit 16.
7, and a switching section 18 for switching between the video signal from which the control pulse has been removed and the video signal from the reference camera 7 via the buffer section 9.

Each of the cameras 7 and 8 includes a pulse separation unit 19 that separates and demodulates the control pulse superimposed on the horizontal blanking period of the output video signal, and an amplification unit that amplifies the demodulated control pulse signal by a predetermined amount. 20, a DC converter 21 that converts the amplified control pulse signal into a DC signal, and a synchronous phase adjuster 22 that adjusts the horizontal phase shift according to the DC control pulse.

Note that the synchronization phase adjustment section 22 controls the oscillation circuit that generates the clock for the process section 1 as in the conventional case, and adjusts the phase shift of the horizontal synchronization signal of the signal being processed by the process section 1. I will do it. Further, a synchronous coupling signal is exchanged between the cameras 7 and 8 via the controller device 6.

Next, to explain the operation of the CCTV system having the above configuration, each of the cameras 7 and 8 installed at a predetermined location is connected to the controller device 6 via a cable. At this time, a reference camera is determined. , this standard camera 7
It is assumed that the horizontal synchronization of other cameras 8 is adjusted.

In this case, the video signal from the reference camera 7 is input to the first synchronization separator 10 via the buffer section 9, and the video signal from the synchronized camera 8 is input to the second synchronization separator 10 via the mixer 16. The signal is input to the synchronization separator 11 of. 1st
The horizontal synchronization signals separated by the second synchronization separation sections 10 and 11 are input to the phase comparison section 12, and the phase difference between them is obtained. The pulse converter 13 generates a control pulse according to the horizontal phase shift, and the pulse level controller 14 adjusts the level of this control pulse.

The control pulse obtained in this way is synchronized with the timing of the horizontal synchronization signal of the second synchronization separation section 11 in the synchronization coupling section 15, that is, the control pulse is synchronized with the horizontal blanking period of the video signal from the camera 8. It is said to be the timing of A control pulse at that timing is superimposed on the video signal in the mixer 16,
The control pulse is transferred to the synchronized camera 8 side.

On the other hand, in the synchronized camera 8, an internal pulse separator 19 separates the control pulse superimposed on the output video signal, and an amplifier 20 converts the signal of the separated control pulse to the following required level. is amplified. This predetermined amplified control pulse signal is converted by the DC conversion section 21 into a DC signal whose horizontal phase can be adjusted, and this DC signal is input to the synchronous phase adjustment section 22 .

In the synchronization phase adjustment section 22, the oscillation circuit of the processing section 1 is controlled according to the phase shift with respect to the video signal from the reference camera 7, as in the conventional case, and when processing the signal of the processing section 1, the oscillation circuit of the processing section 1 is controlled. Phase adjustment is performed so that the signal matches the video signal from the reference camera 7 in phase. As a result, the horizontal phase of the video signals from other synchronized cameras 8 is automatically matched to the reference camera 7, so if these video signals are switched by the switching unit 18,
Images from the synchronized cameras 7 and 8 are displayed on the screen of the monitor device.

In this way, on the controller device 6 side,
It detects the horizontal phase shift of the video signals of each camera 7 and 8, generates a control pulse corresponding to this phase shift, and superimposes this control pulse on the horizontal blanking period of the input video signal to the camera 8 side. transfer,
On the camera 8 side, the phase shift of the horizontal synchronization signal is adjusted to the output video signal according to the control pulse, so that it matches the reference camera 7, so each camera 7, 8
By connecting the controller device 6 to the controller device 6 and outputting video signals from each camera 7, 8, the horizontal phase of each camera 7, 8 is automatically adjusted.

Therefore, when installing a CCTV system, even if the length of the installed cable differs depending on the installation location of each camera 7, 8, phase adjustment is automatically performed.
The CCTV system will be easier to install, and the cost of construction will be reduced.

[0020] In the above embodiment, the case where the CCTV system has two cameras has been described, but even if more cameras are installed, the phase adjustment is automatically performed in the same way. In this case, the number of circuits in the controller device 6 is increased according to the number of cameras used, and the phase shift between the horizontal synchronization signal of the video signal from one reference camera and the horizontal synchronization signal of the video signal from each camera is detected. However, control pulses corresponding to these phase shifts may be superimposed on the horizontal blanking period of the video signal from each camera.

[0021]

[Effect of the invention] As explained above, the CCT of this invention
According to the V system, the controller device switches video signals from multiple cameras and outputs them to a monitor device.
Using one camera as a reference, separate the horizontal synchronization signal of the video signal from this reference camera, separate the horizontal synchronization signal of the video signal from other synchronized cameras, and calculate the phase shift of these separated horizontal synchronization signals. and a superimposing means for superimposing the generated control pulse on the horizontal blanking period of the video signal from the synchronized camera. The camera is equipped with a synchronization phase adjustment means that separates the control pulse superimposed on the output video signal and adjusts the horizontal phase shift of the output video signal according to the separated control pulse. The horizontal synchronization signal of the video signal from the camera and other synchronized cameras can be automatically synchronized, and when installing a CCTV system, the synchronization between each camera can be adjusted according to the length of the installed cable. There is no need for it, the installation is easy, and the installation cost can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic partial block diagram of a CCTV system showing an embodiment of the present invention.

[Figure 2] CCCT used in conventional CCTV system
Schematic block diagram of V camera

[Explanation of symbols]

6 Controller device 7 Camera (standard) 8 Camera (synchronized) 10 First synchronization separation unit 11 Second synchronization separation unit 12 Phase comparison section 13 Pulse conversion section 14 Pulse level control section 15 Synchronous coupling part 16 Mix section 18 Switching section 19 Pulse separation section 22 Synchronous phase adjustment section

Claims (2)

[Claims] 1. A CCTV system in which a plurality of CCTV cameras are connected to at least one monitor device via a controller device, and video signals from the CCTV cameras are switched or simultaneously output to the monitor device, the controller device comprising: , a pulse generating means that uses one of the CCTV cameras as a reference and generates a control pulse according to a phase shift of a synchronization signal of a video signal from the reference CCTV camera and another synchronized CCTV camera; The control pulse is superimposed on the horizontal blanking period of the video signal to
A superimposing means for outputting the output to a CCTV camera other than the camera, and a pulse filter means for removing the control pulse superimposed on the video signal from each of the CCTV cameras, and each of the CCTV cameras receives the control pulse from the controller device. The apparatus includes a pulse separation means for demodulating, and a phase adjustment means for adjusting the horizontal phase shift of the output signal according to the demodulated control pulse, and automatically adjusts the horizontal phase of the video signal from each CCTV camera. A CCTV system characterized by: 2. The pulse generating means is configured to generate the reference C.
A first synchronization separation unit that separates a horizontal synchronization signal of a video signal from a CTV camera, a second synchronization separation unit that separates a horizontal synchronization signal of a video signal from another CCTV camera, and the first synchronization A phase comparison section that compares the phases of the horizontal synchronization signal separated by the separation section and the horizontal synchronization signal separated by the second synchronization separation section and detects a phase shift, and a pulse that outputs a control pulse according to the detected phase shift. It is composed of a conversion section and a pulse level control section, and the superimposition means is composed of a synchronization coupling section and a mix circuit for superimposing the control pulse on the horizontal blanking period of the video signal from each of the CCTV cameras. CCTV system.