JPH05191806A - Monitoring device - Google Patents

Abstract

PURPOSE:To improve the monitoring efficiency in a monitoring device recording the video signal from plural TV cameras in a rotary head type magnetic video recording reproducing device by successively switching the signal to freely set the recording frequency of the video signal of each TV camera in accordance with the significance degree of the monitoring range of each TV camera. CONSTITUTION:The monitoring degree of each camera is made proper by switching a switch 2 by a weighing switching circuit 10 in accordance with the recording frequency command of a camera signal set by a weighing setting circuit 11, by successively extracting plural camera output video signals, superimposing a camera No. identification signal on the extracted video signal by a identification signal superimposing circuit 12 and recording it, by discriminating an identification signal at the time of performing a reproduction and by writing the only video signal of the same camera in a field memory 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical scan type rotary head type magnetic recording / reproducing apparatus for sequentially recording a video signal from a television camera as a recording track inclined with respect to the longitudinal direction of a magnetic tape by a rotary magnetic head. VTR)
The present invention relates to a monitoring device for intermittently recording data on a recording device, and particularly, by weighting the recording frequency of video signals from a plurality of cameras,
It is characterized in that recording / reproducing is performed in time division on a magnetic tape of a book.

[0002]

2. Description of the Related Art In recent years, in the field of surveillance, a system is generally used in which a plurality of cameras are installed and their video signals are recorded / reproduced on a single magnetic tape by a VTR. At this time, it is uneconomical to record all the video signals of a plurality of cameras, and a method of thinning out a plurality of video signals evenly and recording them on one magnetic tape in a time division manner is adopted.

FIG. 4 shows a conventional monitoring VT of this type.
It is a block diagram which shows an example of the camera video signal switching part and reproduction | regeneration part of R. In FIG. 4, 1 is a VTR for recording / reproducing a video signal, and 3 is a sequential switching circuit for sequentially switching the switch 2 for each head switching pulse 9 from the VTR. Nos. 4 to 7 are camera numbers. 1-No.
4 video signals, which are in phase synchronization with each other. Reference numeral 8 is a recording video signal extracted from the video signal of each camera in units of one field and recorded by the VTR 1. Here, it does not matter whether the recording speed is the normal mode or the time-lapse mode.

FIG. 5 shows a recording track pattern diagram when recording is performed by these systems. Camera No. 1 to
No. 4 video signals are sequentially recorded for each track.

During reproduction, the reproduction signal 13 from the VTR 1 is input to the field memory 15, the memory is written every four fields, and the same field signal is repeatedly read out for four field periods, so that only a camera recording signal is reproduced on the monitor 16. It becomes possible.

[0006]

The above is the conventional method of time-division recording video signals of a plurality of cameras on one tape. However, if all the images from the cameras being monitored are equally important, there is no problem, but there may be cases where you want to focus only on the images from a certain camera or when the images from a certain camera are not very important. .. In the conventional method, the images of all the cameras are recorded evenly, so that the above demand cannot be met.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to enable a user to set the frequency of recording on one tape according to the priority of images of a plurality of cameras. ..

[0008]

According to another aspect of the present invention, there is provided a monitoring device for switching the video signals from a plurality of television cameras, which are synchronized with each other, on a field-by-field basis by a switching means capable of changing the switching frequency for each television camera. The video signals of the extracted one field are sequentially recorded on the same magnetic tape by a rotary magnetic head as recording loci inclined with respect to the longitudinal direction of the magnetic tape, and reproduced at the time of reproduction. The video signal of one field is repeatedly displayed on the monitor screen until the next video signal of the same TV camera is reproduced.

[0009]

According to this structure, the frequency of recorded camera images can be changed in accordance with the set priority, so that the efficiency of monitoring can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of a camera video signal switching unit and a reproducing unit of a surveillance VTR according to an embodiment of the present invention. The same blocks as those in the conventional example of FIG. 4 are designated by the same reference numerals. The difference from the conventional example is that a weight setting circuit 11 and a weight switching circuit 10 are provided, and the weight switching circuit 10 switches the switch 2 in accordance with a recording frequency command of a camera signal set by the weight setting circuit 11.

In FIG. 1-No. 4 shows a recording track pattern diagram when four cameras of No. 4 are used and the weighting of each is set to 4: 3: 2: 1. The camera No. is set every 10 recording tracks. 1 times 4 times, camera No. Two
3 times, camera no. No. 3 twice, camera no. No. 4 is recorded once.

However, the video signal of the same camera cannot be reproduced by simply writing the data in the memory every four fields simply by changing the recording frequency. Therefore, when recording
In the identification signal superimposing circuit 12, the camera No. The identification signal for each is superimposed and recorded by the VCR 1. An example of the identification signal is shown in FIG.
Shown in.

(A) shows the first field of the vertical blanking period of the TV signal. (B) is the camera number. In order to identify 1, the white level pulse is superposed on the first horizontal sync pulse immediately after the equalization pulse after the vertical sync pulse in the vertical blanking period of the first field. (C)
Indicates the case of the second field, and the camera number. Two
In order to identify the same pulse, the same pulse is superimposed on the second pulse from the same position as above. No. 3 and No. Similarly, for the camera output of No. 4, the white level pulse is superimposed and recorded on the third and fourth horizontal synchronizing pulses.

At the time of reproduction, the reproduction signal 13 is discriminated by the discrimination signal discriminating circuit 14 from the above position, and the designated camera number. Only signal of field memory 15
, And only the signal of the same camera is repeatedly displayed on the monitor 16 until the video signal of the same camera is reproduced.

In the case of a system in which the vertical sync pulse is also required to be memorized, it is slow if it is memorized after being identified. The identification signal of 1) may be superposed and recorded on the video signal of one field before, and the reproduced next field may be stored in memory during reproduction.

[0016]

As described above, according to the present invention, by providing the weight setting circuit and the weight switching circuit, the user can set the recording frequency of a plurality of camera signals, and the same camera can be used during reproduction. Therefore, it is possible to realize an excellent monitoring device that can adjust the degree of monitoring of each camera to an appropriate level because only the signal of 1) can be reproduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a monitoring device according to an embodiment of the present invention.

FIG. 2 is a recording track pattern diagram on a magnetic tape recorded by the embodiment of the present invention.

3 is a diagram showing a camera No. according to an embodiment of the present invention. TV signal waveform diagram showing identification signal superposition method

FIG. 4 is a block diagram of a conventional monitoring device.

FIG. 5 is a recording track pattern diagram on a magnetic tape recorded by a conventional device.

[Explanation of symbols]

 1 VTR 2 switch 10 weighting switching circuit 11 weighting setting circuit 12 identification signal superimposing circuit 13 reproduction signal 14 identification signal discriminating circuit 15 field memory 16 monitor

Claims (2)

[Claims] 1. A video signal from a plurality of TV cameras synchronized with each other is sequentially switched and extracted in a unit of one field in accordance with the switching frequency by a switching means capable of changing the switching frequency for each TV camera, and the extracted signals are extracted. The video signals of one field are sequentially recorded on the same magnetic tape by the rotary magnetic head as recording loci inclined with respect to the longitudinal direction of the magnetic tape, and the reproduced video signal of one field is reproduced at the next same television camera. A monitoring device that repeatedly displays on the monitor screen until the video signal of is reproduced. 2. The same magnetic tape is successively recorded by rotary magnetic heads as recording loci inclined with respect to the longitudinal direction of the magnetic tape by attaching an identification signal to the video signal of one field extracted from each television camera by the switching means. The monitoring device according to claim 1, characterized in that