JPH0583632A - Supervisory video recorder - Google Patents

Abstract

PURPOSE:To improve the detecting accuracy of an identification signal representing a camera number that can be superimposed in the vertical blanking period of a video signal. CONSTITUTION:The video signals from plural television cameras to which the camera numbers are allocated are switched at every frame by a change-over switch 2, and are fetched in a recording signal output circuit 3, and the same identification signal to identify the camera number is superimposed for at least two times, respectively in the 1H interval of the vertical blanking period at a superposition circuit 4, and they are recorded on a VTR 9. This recorder is comprised of an identification circuit 5, a decision circuit 6 in which the identification signal detected by the identification circuit 5 is fetched by a reproducing signal from the VTR 9 and which decides that a detected identification signal is effective only when the same signal is detected for at least two times, memory 7 in which the reproducing signal is rewritten and is stored transiently based on a decision result, and a video signal output circuit 8 which outputs the reproducing signal read out from the memory 7 as the video signal for monitor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surveillance video recording apparatus, and more particularly to a surveillance video recording apparatus equipped with a frame switcher for switching and recording video signals from a plurality of television cameras for each frame.

[0002]

2. Description of the Related Art FIG. 3 shows a block diagram of a conventionally known surveillance video recording apparatus U2. In this figure, video signals from a plurality of television cameras 1 are sequentially switched for each frame by a changeover switch 2 which is a frame switcher and input to a recording signal output circuit 3. In the recording signal output circuit 3, the captured video signal is subjected to signal processing such as maintaining continuity of odd and even fields and subcarriers, and can be recorded in a video tape recorder 9 (hereinafter referred to as VTR 9). Converted to a signal. The recording signal from the recording signal output circuit 3 is input to the superimposing circuit 4, and the identification signal 13 representing the camera number is superimposed in the vertical blanking period as shown in FIG. The recording signal on which the identification signal 13 is superimposed is recorded in the VTR 9. Note that reference numeral 12 is a video signal.

The signal reproduced from the VTR 9 is input to the discrimination circuit 5 so that the superimposed discrimination signal 13 is detected, and the video signal of only the video period of the designated arbitrary TV camera is discriminated and selected. Thus, the video signal for one frame is temporarily recorded in the memory 7. At this time, the video signal periods of the other TV cameras are not recorded, and only the video signals of the same video camera are read while being sequentially recorded in the memory 7, and the video signals of the same camera output from the video signal output circuit 8 are output. It is displayed on the monitor 10. As a result, only the video of an arbitrary TV camera can be selectively reproduced.

[0004]

By the way, particularly in a time-lapse VTR or a long-time VTR, the video signal recorded / reproduced on the tape has a disturbed signal level within the vertical blanking period due to a tracking error or the like, or a sync signal of Synchronization may be disturbed. Therefore, in the conventional surveillance video recording device U2, 1 is set as the identification signal 13 of the camera number.
By superimposing a high level signal or a low level signal for several H in the horizontal period (1H) in the superimposing circuit 4, it is possible to prevent an identification error caused by a tracking error.

When the identification signal 13 is written over several H's in this way, the information that can be superimposed within the vertical blanking period of limited length is limited to only the camera number, and the date and time information is stored. It was not possible to superimpose the year, month, day, minute, second data and alarm information from external sensors.

The present invention has been proposed in order to solve the problems of the prior art as described above, and improves the detection accuracy of the identification signal representing the camera number, and the date and time information in addition to the camera number. It is an object of the present invention to provide a monitoring video recording device capable of superimposing alarm information from an external sensor or the like on a vertical blanking period of a video signal.

[0007]

In order to achieve this object, the present invention provides a selector switch for sequentially switching and outputting video signals from a plurality of television cameras to which camera numbers are assigned, one frame at a time. Before recording on the video tape recorder, the recording signal output circuit that converts the video signal from the selector switch into a recording signal that can be recorded on the video tape recorder and outputs it, and the identification signal that identifies the camera number in the video signal corresponding to each TV camera. An identification signal superimposing circuit for superimposing on, an identification circuit for detecting the identification signal from the reproduction signal reproduced from the video tape recorder, arbitrarily selecting and outputting a reproduction signal corresponding to the camera number, and an identification circuit from this identification circuit. A memory that temporarily stores the playback signal and a video signal that can be displayed on the monitor with the playback signal read from this memory. In a surveillance video recording device having a video signal output circuit for outputting, the detected identification signal is valid only when the identification signal detected by the identification circuit is taken in and the same signal is detected at least twice. A determination circuit for determining that the reproduction signal is rewritten to the memory based on the determination result of the detection circuit.

Further, the surveillance video recording apparatus according to the present invention uses the same signal as an identification signal for identifying the camera number at least twice during one horizontal scanning period of the vertical blanking period of the video signal corresponding to each television camera, by a video tape. The identification signal superposition circuit to be superposed before recording on the recorder and the identification signal detected by the identification circuit are fetched, and the detected identification signal is effective only when the same signal is detected at least twice. A judgment circuit for judgment is provided, and the reproduction signal is rewritten to the memory based on the judgment result of this judgment circuit.

[0009]

According to the above-described structure, the identification signal is determined to be valid when the same signal is detected at least twice in the determination circuit, and the contents of the memory are rewritten at this time. Therefore, when the identification signal cannot be detected due to a tracking error or the like, the memory is not rewritten based on the determination result of the determination circuit, so that the video signal stored immediately before is repeatedly read from the memory, Only the video corresponding to the specified camera number can be output to the monitor without malfunction. Moreover, since the detection accuracy of the identification signal is improved by this configuration, it becomes possible to superimpose information other than the camera number in the vertical blanking period.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the surveillance video recording apparatus according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of this surveillance video recording device. In this figure, video signals from a plurality of television cameras 1 to which camera numbers are assigned are switched by the changeover switch 2 for each frame and taken into the recording signal output circuit 3 to be recorded signals which can be recorded in the VTR 9. To be fixed. In this recording signal, an identification signal 11 for identifying the camera number in the superimposing circuit 4 is at least 2 as shown in FIG.
The same signal is superimposed on each 1H section of the vertical blanking period. The recording signal on which the identification signal 11 is superimposed is recorded on the VTR 9.

The recording / playback signal played back from the VTR 9 is
The identification signal is input to the identification circuit 5, and the identification signal 11 corresponding to the designated camera number is detected in the identification circuit 5. The identification signal 11 from the identification circuit 5 is sent to the determination circuit 6, and when the same identification signal 11 is detected at least twice in the determination circuit 6, it is determined that the detected identification signal 11 is valid. It After the identification signal is read by the identification circuit 5 and the determination circuit 6, the video signal for one frame corresponding to the corresponding camera number is first stored in the memory 7.
Memorized in. Therefore, while the identification signal 11 is not read, the video signal in the memory 7 is not rewritten. The video signal reproduced from the memory 7 is sent to the video signal output circuit 8, and the video corresponding to the same camera number output from the video signal output circuit 8 is displayed on the monitor 10.

The surveillance video recording device U having the above-mentioned structure
1, the video signal recorded / reproduced on / from the tape of the VTR 9 is disturbed in the signal level of the video signal within the vertical blanking period due to a tracking error or the like, or the synchronization of the sync signal is disturbed. Even if it becomes unidentifiable or misidentified,
Since the video signal is not rewritten in the memory 7 by the function of the determination circuit 6, the video signal of the correct camera number stored immediately before is repeatedly output as a video. Further, in the surveillance video recording device U1, since the detection accuracy of the camera number is high, it is not necessary to superimpose the identification signal over a plurality of Hs as in the conventional case, and not only the camera number but also the date and the like within the vertical blanking period. Time information, alarm information from an external sensor, etc. can be superimposed.

In the above-described embodiment, the identification signal 11 of the camera number is superimposed on 1H as a 2-bit signal (the same signal is repeated twice), but 3 bits or more on 1H, that is, the same signal is repeated three times or more. By repeating the above, the amount of information that can be superimposed during the vertical blanking period can be further increased.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the gist.

[0015]

As described above, according to the present invention, in superimposing the identification signal for identifying the camera number in the vertical blanking period, the same signal is superposed at least twice in one horizontal scanning period to make a determination. At least 2 in the circuit
When the same identification signal is detected once, it is determined that the camera number has been read, so that it is possible to improve the detection accuracy of the camera number as compared with the related art. As a result, it becomes possible to superimpose date information, time information, and alarm information from an external sensor on the vertical blanking period, which has been impossible in the past. Since these pieces of information are important information when recording video signals from a plurality of surveillance cameras, the present invention has the effect of increasing the effectiveness of the surveillance video recording apparatus.

[Brief description of drawings]

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

FIG. 2 is a waveform diagram showing an identification signal recorded in the vertical blanking period by the surveillance video recording device of FIG.

FIG. 3 is a block diagram showing an embodiment of a conventional surveillance video recording device.

FIG. 4 is a waveform diagram showing an identification signal recorded in a vertical blanking period by a conventional surveillance video recording device.

[Explanation of symbols]

 U1 Monitoring video recording device 1 Television camera 2 Changeover switch 3 Recording signal output circuit 4 Superimposing circuit 5 Discrimination circuit 6 Judgment circuit 7 Memory 8 Video signal output circuit 9 VTR 10 Monitor 11 Identification signal 12 Video signal

Claims (2)

[Claims] 1. A selector switch for sequentially switching and outputting, for each frame, video signals from a plurality of television cameras to which camera numbers are assigned, and a recording signal for recording the video signal from the selector switch on a video tape recorder. The recording signal output circuit that outputs the video signal corresponding to each TV camera, the identification signal superimposing circuit that superimposes the identification signal for identifying the camera number on the video signal corresponding to each TV camera before recording on the video tape recorder, and the reproduction signal from the video tape recorder. An identification circuit that detects the identification signal from the reproduced signal and arbitrarily selects and outputs the reproduction signal corresponding to the camera number;
A monitoring video recording apparatus having a memory for temporarily storing a reproduction signal from the identification circuit and a video signal output circuit for outputting the reproduction signal read out from the memory as a video signal which can be displayed on a monitor. Only when the detected identification signal is captured and the same signal is detected at least twice,
A surveillance video recording apparatus comprising a judgment circuit for judging that the detected identification signal is valid, and the reproduction signal is rewritten to the memory based on the judgment result of the judgment circuit. 2. A changeover switch for sequentially changing and outputting, for each frame, video signals from a plurality of television cameras to which camera numbers are assigned, and a recording signal for recording the video signal from the changeover switch on a video tape recorder. The recording signal output circuit that outputs the video signal corresponding to each TV camera, the identification signal superimposing circuit that superimposes the identification signal for identifying the camera number on the video signal corresponding to each TV camera before recording on the video tape recorder, and the reproduction signal from the video tape recorder. An identification circuit that detects the identification signal from the reproduced signal and arbitrarily selects and outputs the reproduction signal corresponding to the camera number;
In a surveillance video recording device having a memory for temporarily storing a reproduction signal from the identification circuit and a video signal output circuit for outputting the reproduction signal read from the memory as a video signal which can be displayed on a monitor, An identification signal superposition circuit for superposing the same signal as an identification signal for identifying the camera number at least twice before recording on the video tape recorder in one horizontal scanning period of the vertical blanking period of the corresponding video signal, and the above identification circuit. And a determination circuit that determines that the detected identification signal is valid only when the same identification signal is detected at least twice.
A monitor video recording apparatus characterized in that the reproduction signal is rewritten to the memory based on the result of the judgment by the judgment circuit.