JPS62292087A - Monitor - Google Patents

Abstract

PURPOSE:To increase the recording capacity of a tape by recording a video signal in a recording device only when a video pattern picked up by a monitoring Camera is changed. CONSTITUTION:The contents of n sampling video information obtained from the monitoring camera 1 are alternately extracted in each frame through a synchronizing sepatator circuit 6, a gate circuit 7, a gate pulse generating circuit 8, and a frame switching circuit 9 and stored in memory circuits 11, 12 respectively. Change ditecting circuits 13, 14 compare the information of one frame before with the current information, and at the time of existence of a change, output detection signals. The detection signals are synthesized by a synthesizing circuit 15 and output 4 from a retrigger circuit 16 is inputted to a control signal input terminal 6 and a time generating circuit 17. The output of the circuit 17 is inputted to a multiplex circuit 18 and multiplexed with a video signal outputted from the camera 1 and the multiplexed signal is applied to a recording device 2. Consequently, the recording device 2 is driven to record the video signal outputted from the camera 1. Thus, the recording capacity of the tape can be increased.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention Industrial Field of Application The present invention is applicable to a surveillance system in a pill (in an elevator, etc.) or a supermarket, in which a change occurs in the image pattern captured by a surveillance camera. The present invention relates to a monitoring device that records a video signal on a recording device only when the video signal is displayed.

Conventional technology A conventionally employed surveillance system is shown in Fig. 4. In Fig. 4, 1 is a surveillance camera, 2 is a recording device such as a VTR, 3 is a timer, and 4 is a device that records video signals from the surveillance camera 1. A video signal input terminal 5 is used to input a video signal to the apparatus 2, and a control signal input terminal 5 is used to input a control signal from the timer 3 to the recording apparatus 2. A video signal captured by the surveillance camera 1 is input to the recording device 2 via the video signal input terminal 4. The recording device 2 performs recording according to a control signal from a timer 3 that turns on and off at fixed time intervals.
The video signal of the surveillance camera 1 is recorded on tape.

Problems to be Solved by the Invention However, in the above configuration, the video signal of the surveillance camera is recorded by a timer set at fixed time intervals, so the surveillance recording capability depends on the time set by the timer. was. If the recording interval is short, the video needed for monitoring will be missing, and if the recording interval is long, the same video (video that should be wasted) will continue to be used.There were also problems with the recording capacity of the tape.

The present invention has been made in view of this point, and it increases the recording capacity of the tape by automatically recording the video signal on the recording device only when a change occurs in the video pattern captured by the surveillance camera. It is an object of the present invention to provide a monitoring device that can be realized with a simple configuration.

Means for Solving the Problems In order to achieve the above object, the present invention provides a storage means for extracting n (n = integer) sampling lines from the scanning line of a surveillance camera and storing the image information for each frame. and a detection means for comparing the stored image information and the image information one frame later and detecting a changed part, and a detection means operated by a detection signal obtained by the detection means, and from a state where the detection signal has stopped. A holding means holds the detection signal for several tens of frames, and a recording device is operated with the holding signal obtained by the holding means, and other information is multiplexed onto a part of the video signal of the surveillance camera and supplied to the recording device. This is a monitoring device equipped with means to

Effect: With the above-described configuration, the present invention checks n sampling image information from a surveillance camera frame by frame, detects any change in any sampling point at the same position, and outputs the detection signal. The video signal from the surveillance camera is automatically recorded on the recording device.

Embodiment FIG. 1 is a block diagram showing an embodiment of the monitoring device of the present invention. FIG. 2 is a timing chart for explaining the operation of the same embodiment. Figure 3a.

b is an explanatory diagram showing sampling points on the screen for obtaining image information of the surveillance camera in the same embodiment.

In FIG. 1, the same parts as in FIG. 4 are given the same numbers. 6 is a synchronization separation circuit, 7 is a gate circuit, 8 is a gate pulse generation circuit, 9 is a frame-by-frame switching circuit, and 10 is an A/
D converter, 11 is a first memory circuit, 12 is a second memory circuit, 13 is a first change detection circuit, 14 is a second change detection circuit, 15 is a synthesis circuit, 16 is a retrigger timer circuit, 17
1 is a time generation circuit, and 18 is a multiplex circuit.

In Fig. 2, B) is the video signal output waveform of the surveillance camera 1, (B) is the output waveform of the gate pulse generation circuit 8, and C''
9 is the stored waveform of the first memory circuit 11, 2) is the stored waveform of the second memory circuit 12, (E) is the output waveform of the first change detection circuit 13, and (F) is the output waveform of the second change detection circuit 14. ,
(G) is an output waveform of the synthesis circuit 15, (G) is an output waveform of the re-trigger timer circuit 16, and (S) is a waveform indicating the recording state of the recording device 2.

Next, the circuit operation will be explained.

The video signal ratio of the surveillance camera 1 is input to a synchronization separation circuit 6, a gate circuit 7, and a multiplexing circuit 18, respectively.

A synchronization signal is separated from the video signal ratio by a synchronization separation circuit 6, and the output is input to a gate pulse generation circuit 8 and a frame-by-frame switching circuit 9.

The gate pulse generation circuit 8 generates pulses from the first to nth pulses set at arbitrary intervals from the scanning line of the surveillance camera 1 shown in FIG. 3a.
A gate pulse (b) is generated to extract the video information of the sampling line.

This is because the background image inside an elevator or a supermarket is constant, so it is not necessary to sample the entire scanning line of the surveillance camera just to detect the movement of a large object or an object. line is sufficient.

The output ←) of the gate pulse generation circuit 8 is input to the gate circuit 7, which gates the video signal from the surveillance camera 1.

The output of the gate circuit 7 is input to the A/D conversion circuit 1o. The A/D conversion circuit 10 converts the analog signal sampled by the gate circuit 7 into a digital signal.

The digital signal output of the A/D conversion circuit 10 is transmitted to a first memory circuit 11, a second memory circuit 12, and a first change detection circuit 13.
, are respectively input to the second change detection circuit 14.

first and second memory circuits 11, 12, first and second
The output of the A/D converter 10, which is input to the change detection circuit 13.
In the D converter, from the 4th bit to the upper pit, 6 bits)A
In the /D converter, the respective pit outputs (from the 3rd bit to the 4th bit to the upper pit) are connected. this is,
When all pit outputs of the A/D converter 10 are used,
Although it depends on the mounting state of the A/D converter 10, it is difficult to detect changes in the image on the lower pit side because the changes occur due to low-level noise. This is also because the intermediate pit output or more of the A/D converter is sufficient to obtain changes in video information.

A frame-by-frame switching circuit 9 that turns on and off every frame and outputs two types of switching pulses: anti-EQbj and non-inverse-Q.
The output of
The other input is input to the change detection circuit 13 , and the other input is input to the second memory circuit 12 and the second change detection circuit 14 .

The first memory circuit 11 writes the A/D conversion output of each line sampled in the first frame and reads it out in the second frame, as shown in (c).

The output of the first memory circuit 11 is input to the first change detection circuit 13.

The first change detection circuit 13 detects the information of the previous frame read out by the first memory circuit 11 and the current information (
(information on the second frame) is compared and detected by exclusive ORing or the like.

If the information is different from one frame ago, it will be changed at the sample point.”
If the information is the same, the signal (e) will be at the "1" level and will be at the "0" level.

Further, the second memory circuit 12 and the second change detection circuit 14
Similarly, as shown in (b) and (f), the A/D conversion output of each line sampled in the second frame and the A/D conversion output of each line sampled in the next frame are compared and detected. (U)

In addition, as shown in Figure 3, by further providing several arbitrary sample points on each sampling line and inputting the image information of only those sample points to the memory circuit,
It is possible to reduce the capacity of the memory circuit. The output of the second change detection circuit 14 is input to the synthesis circuit 15.

An output (g) of a combining circuit 16 that combines the output of the first change detection circuit 13 and the output of the second change detection circuit 14 is input to a re-trigger type timer circuit 16.

The retrigger type timer circuit 16 has a delay time of several tens of frames, and if a retrigger is input within the delay time,
There will be a delay of several tens of frames again from the time the re-trigger is input.

This means that if the frame interval in which the change was detected was short, for example, if the change occurred only during 6o frames,
The amount is detected for about 2 seconds (60 x 1/30 seconds) and the video signal is recorded on the recording device, but when the supervisor monitors it later, it is very difficult to see if it is only displayed for about 2 seconds. Therefore, even if there is no detection, it will continue for several tens of frames (optional)
The recording time is maintained in the recording device so that it can be recorded for an extended period of time.

The output (g) of the retrigger timer circuit 16 is input to the control signal input terminal 5 and the time generation circuit 17, respectively.

The time generation circuit 17 is provided to multiplex information such as the current time or channel number onto a part of the video signal of the surveillance camera 1. The output of time generation circuit 17 is input to multiplex circuit 18 . The multiplexing circuit 18 multiplexes the video signal from the surveillance camera 1 and the signal from the time generation circuit 17 and outputs the multiplexed signal to the video signal input terminal 4. The recording device 2 operates in the state shown in ω) by signals from the control signal input terminal 5 and the video signal input terminal 4.

As described in detail, according to the present invention, the video signal is automatically recorded in the recording device only when a change occurs in the video pattern captured by the surveillance camera. The practical effect is great because it can be realized with a simple circuit configuration and only requires a recording tape.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a monitoring device in an embodiment of the present invention, Fig. 2 is a timing chart for explaining the operation of the embodiment, and Fig. 3 a and b are images of a surveillance camera in the embodiment. An explanatory diagram showing sampling points for obtaining information on a screen, FIG. 4 is a block diagram of a conventional monitoring device in a monitoring system. 6... Synchronous separation circuit, 7... Gate circuit, 8... Katehals generation circuit, 9...
...Frame-by-frame switching circuit, 10-5.・,・A/D converter, 11...First memory circuit, 12...
・Second memory circuit, 13...First change detection circuit, 14...Second change detection circuit, 15...
・Synthesis circuit, 16... Re-trigger timer circuit,
17...Time generation circuit, 18...Multiple circuit.

Claims (3)

[Claims] (1) Extract n pieces (n = integer) of sampling image information from the scanning line of the surveillance camera, and divide the image information into 1
A detection means stores information for each frame and compares the stored image information with image information one frame later to detect a change. A monitoring device comprising: means for holding an output; and means for operating a recording device with a holding signal obtained by the holding means, multiplexing other information onto a part of the video signal of the monitoring camera, and supplying the same to the recording device. (2) The detection means includes a sync separation circuit that separates a sync signal from a video signal of the surveillance camera, and a gate pulse generation circuit that generates n sampling pulses corresponding to the scanning line of the surveillance camera from the output of the sync separation circuit. , an A/D converter that gates the video signal of the surveillance camera and converts it into digital data using the output of the gate pulse generation circuit; and a storage circuit that alternately stores the output of the A/D converter for each frame; Claim 1 characterized in that it comprises a comparison detection circuit that compares the stored output of the storage circuit and the output of the A/D converter processed one frame later to detect a change. monitoring equipment. (3) The monitoring device according to claim 1 or 2, wherein the holding means holds the detection signal for at least a plurality of frames from the time when the detection signal from the detection means stops.