JPH02195786A - Video recording system - Google Patents

Abstract

PURPOSE:To obtain a system with high efficiency by enabling recording to be performed by switching a video signal at high speed by writing video information by the synchronizing signal of the video signal, and reading out the content of a memory by a reference synchronizing signal. CONSTITUTION:When a switching part 5 selects the video of a camera 2, a synchronous component is extracted from the video signal at a separation circuit 6, and is supplied to a memory part 8, and the video component of the camera 2 is written on the memory 8. The video information written on the memory part 8 is read out with the timing of the reference synchronizing signal, and also, the reference synchronizing signal is attached D on the information, then, it is sent to a VTR 11 and a video monitor 12.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is directed to switching a plurality of mutually asynchronous video signals to
The present invention relates to a video recording system for recording to R.

[Summary of the invention]

If a plurality of mutually asynchronous video signals are simply switched and recorded on a VTR, the synchronization of the servo system that controls the VTR's drums, capsulators, etc. will be disrupted.

It may take several seconds for the mechanical system to stabilize and normal recording to occur. This makes it difficult to realize a system that switches video signals at high speed and records them on a VTR. In order to solve this problem, the present invention provides an input/output asynchronous field or frame memory section after the video switching section, extracts a synchronization signal from the input video signal, and writes video information to the memory section in synchronization with the input video signal. , readout is performed using a reference synchronization signal generated from a synchronization generator.

According to the present invention, even if mutually asynchronous input video signals are switched, since the output synchronization signal is a reference synchronization signal, no disturbance occurs, and the servo system of the VTR is stable, resulting in no disturbance of the video signal. Since the memory synchronization pull-in time can be kept within the 1st to 3rd vertical scanning period, high-speed switching recording is possible.

[Conventional technology]

In a conventional recording system for recording a plurality of mutually asynchronous video signals onto a VTR, as shown in the system diagram of FIG. switching, VTRII via amplifier 10;
It was being sent to video monitor 12, etc. If each camera operates asynchronously, the vertical synchronization phase of each video signal will be different as shown in (G) and 4G) in Figure 5, and if they are switched at the switching point 20, the vertical synchronization phase will be different as shown in Figure 5 (H). As shown in the figure, the synchronization sequence changes between the video signals 18C and 19C, resulting in synchronization disturbance. When this out-of-synchronization video signal is supplied to the VTR 11, the servo system that controls the drum, capstan, and other mechanical systems becomes out of synchronization, and it takes several seconds for one mechanical system to stabilize and normal recording to occur. It may take some time.

In addition, in the above, the switching of the switching unit 5 is performed by a general VTR.
When recording on a computer, etc., it can be done manually or automatically by generating a switching pulse every set time using a VTR or the like. Also, when using a VTR for a long time, a clock pulse for camera switching is output after each recorded field or frame.

The switch is operated by that clock.

[Problem to be solved by the invention]

As mentioned above, in the conventional technology, synchronization disturbance occurs when switching, and when the video signal obtained by switching is supplied to a VTR for recording, it may take several seconds for normal recording to occur. Therefore, there is a problem in that it is necessary to set the switching interval to a period longer than that, assuming that the synchronization of the VTR is disturbed.

An object of the present invention is to solve the above problems and provide an efficient recording system that can switch and record video signals at high speed.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention is provided at a stage subsequent to a switching section that switches a plurality of mutually asynchronous video signals.

A field or frame memory section with asynchronous input and output is provided, and a synchronous signal is extracted from the video signal obtained by switching.
In this synchronization, video information is written to the memory section, and reading from the memory section is performed using a reference synchronization signal 9 from a synchronization signal generation section.

[Effect]

As a result, synchronization disturbances that affect the VTR's servo system can be eliminated, and at the same time, disturbances in the video components when switching video can be avoided for 1 to 3 vertical scanning periods (1/60 to 3760 seconds) of the electrical synchronization pull-in time of the memory section. ), it is possible to configure a video recording system that can record at high speed.

Also, if you use a VTR for a long time,
In order to enable long-term recording, R records the video signal by thinning it out, so it switches the video at the next frame after recording one field or one frame, and records again after 1 to 3 vertical scanning periods. Therefore, it is possible to construct a system in which disturbances in video components are not recorded and are not affected by switching at all.

〔Example〕

Nine embodiments of the present invention will be described below with reference to FIG. The video signals from the connected asynchronous television cameras 1j2 and 1j3 are switched by the switching section 5.

Here, if the video signal from the camera is selected,
A synchronization component is extracted by the synchronization separation circuit 6, and the video information of the camera 1 is written into the memory section 8 at that timing. The video information written in the memory section 8 is read out at the timing of the synchronization signal from the synchronization signal generation section 7, is added with the synchronization signal from the synchronization signal generation section 7 in the synchronization separation circuit 9, and is sent via the amplifier 10 to the VTRII. , is sent to the video monitor 12.

Next, when the switching unit 5 selects the image of camera 2, camera 2
The video signal enters the synchronization separation circuit 6, extracts the synchronization component, and supplies it to the memory section 8, but since the synchronization timing differs from the synchronization timing of the camera 1, it is reset to the first address of writing during writing to the memory. Although disturbances occur in the video components, after the reset, the video components of the camera 2 are correctly written to the memory.

FIG. 2 shows the state of the video at the time of switching. Camera 1, 2.
3 is asynchronous, so the synchronous phases do not match as shown in FIGS. 2(A) and 2(B). When the camera is switched at the timing of the switching point 21, the video signal 1.3 is output from the memory section 8.
The information before the switching point 21 of C and the information of the video signal 13b already written in the previous field will be read out, but the synchronization of the video signal in FIG. 2 (B) that comes after the switching point 21 Since the information of the video signal 14d is written in synchronization with the component, a regular video signal is sent from the field following the video disturbance period 15a. Depending on the phase relationship between the exchange point 21 and the video signals of each camera, the video disturbance period 15a may occur with a width of 1 to 2 fields (1 to 3 fields in the case of frame memory). Note that since the synchronization signal of the output video signal is the reference synchronization signal generated from the synchronization signal generation section 7, no disturbance in synchronization occurs even if the input video is switched.

Next, the case where the VTR is used for a long time will be explained.

In the case of standard 2-hour bone imaging, video signals are recorded every 1/60 seconds, but in long-term recording in 12-hour mode, which is the general maximum recording interval mode of long-term VTRs.

I/60 seconds x 12 hours/2 hours = recording at 1/10 second intervals. This is 6 as shown in Figure 3 (D) and (E).
This means that each field is recorded. In other words, the 5 fields after the VTR has finished recording for a long time are not recorded, so image disturbances are tolerated, and during playback, no image disturbances appear and a good image can be obtained. .

In the above, the video switching section and memory section are
I explained that it was set up separately.

The system may be constructed by incorporating the memory section into the VTR, or by incorporating both the video switching section and the memory section into the VTR.

〔Effect of the invention〕

According to the present invention, even in systems where it is difficult to externally synchronize operation of video equipment such as cameras, efficient monitoring can be achieved by high-speed switching without having to set the recording time by considering the synchronization pull-in time of the VTR's servo system. system can be realized.

In addition, if a VTR is used for a long time, the video disturbances at the time of switching will not be recorded in the recorded video, and a good system can be constructed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the present invention in detail, and FIG. 3 is a waveform diagram for explaining another embodiment of the present invention. FIG. 4 is a block diagram of a conventional example, and FIG. 5 is a waveform diagram for explaining the conventional example. 1.2.3: TV camera, 4: Video switching device with built-in memory, 5: Switching section, 6: Synchronization separation circuit. 7: Synchronization signal generation section, 8: Memory section, 9: Synchronization addition circuit, H: VTRj 12: Video monitor. 13, 14.18.19: Video signal waveform, 15: Disturbed period of video 7, 16: Recording timing of long-time VTR, 17: Video switch, 20.21: Switching point. Second eup, II! 1 (E) 〉

Claims (1)

[Claims] 1. A plurality of video signals are switched by a video signal switching section, and V
In a system for recording to a TR, a field or frame memory section is provided after the video signal switching section,
A synchronizing signal is extracted from the video signal obtained by switching, and video information is written into the memory section in synchronization with the video signal, and reading from the memory section is performed using a reference synchronizing signal generated from a synchronizing signal generating section. A video recording system featuring: 2. The video recording system according to claim 1, wherein the system is constructed by incorporating the field or frame memory section into a VTR. 3. The video recording system according to claim 1, wherein the system is constructed by incorporating the field or frame memory section and the video switching section into a VTR. 4. The video recording system according to claim 1, 2 or 3, wherein a long-time recording VTR is used for the VTR, and recording is performed except for periods of video disturbance.