JPH08235471A - Abnormality monitoring device - Google Patents

Abstract

(57) [Summary] [Purpose] The image before the abnormal phenomenon is detected and V after the abnormal phenomenon is detected.
Provided is an abnormality monitoring device capable of recording an image until the TR is actually activated. [Structure] Image data is taken out by a sync separation circuit 1 based on a video signal from a video camera (not shown). The address counter 3, the field interval setting circuit 5, and the field segment setting circuit 6 create write address / timing of the image data laminated memory 4 and always store the image data in the image data laminated memory 4. When the abnormal phenomenon detection circuit 2 detects an abnormal phenomenon, the start / stop control circuit 8 is activated to stop recording an image after a certain period of time or when the abnormality disappears. V within this fixed time
TR7 is activated to record the subsequent image data. Then, after eliminating the abnormal phenomenon, the data transfer circuit 9 transfers the contents of the image data laminated memory 4 to the storage device 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality monitoring device for detecting an abnormal phenomenon in a monitoring area and recording an image of the abnormal phenomenon.

[0002]

2. Description of the Related Art Conventionally, in public places such as banks and shops where an unspecified number of people come and go, and in facilities such as power plants and power transmission facilities where an intruder may cause a danger, it is necessary to install a video camera for abnormal operation. The presence or absence of is constantly monitored. For monitoring, a method in which human beings monitor while watching in real time, images are always recorded on video tape,
There is a method in which a video tape is reproduced after an abnormality occurs and an abnormal phenomenon is analyzed based on the reproduced image.

However, since it is usually not known when an abnormality will occur, the former method is not efficient because a supervisor is assigned regardless of the presence or absence of an abnormality. Also, in some cases, there is a risk of overlooking the abnormality. Therefore, the latter method is now the mainstream. However, if this method is used as it is, images will continue to be recorded on the video tape even after the abnormality is resolved. Therefore, in order to analyze the abnormality, it is necessary to spend extra time for reproducing the video tape and searching the image recorded for a long time at the time when the abnormality occurs. Therefore, a method has been adopted in which a VTR (video tape recorder) is started after an abnormality occurs and recording is performed only for a certain period from the time of the abnormality occurrence or until the abnormality phenomenon is resolved. It was

[0004]

By the way, in the system in which the VTR is activated and the image is recorded after the abnormality is detected as described above, after the activation of the VTR is instructed by the abnormality detection signal, the video tape is actually transferred. There is a time delay before the recording starts. Therefore, during this time delay period, there is a serious problem that an image of an abnormal phenomenon is not recorded and is lost. Recently, a VTR with a small time delay has been developed, but such a VT
Even if R is used, there is still a period during which an image cannot be recorded.

The present invention has been made in view of the above points, and an object thereof is an image before an abnormal phenomenon is detected, and from the time when the abnormal phenomenon is detected until the VTR is actually activated to start recording an image. An object of the present invention is to provide an abnormality monitoring device that records images of a period without omission.

[0006]

In order to solve the above problems, the invention according to claim 1 compares the past image taken by the video camera with the present image taken by the video camera. An abnormality detecting unit that detects an abnormality and outputs an abnormality signal, a video tape recorder that is activated when the abnormality signal is output, and records an output image of the video camera thereafter, and an output image of the video camera is digital. A fixed capacity memory that is converted into image data and stored, and after storing the fixed capacity image data that is continuously captured at predetermined time intervals, the earliest stored image data is deleted. A memory in which new image data is stored, and a rising time of the video tape recorder that is equal to or longer than the rising time of the video tape recorder after the abnormal signal is output. Once the time has elapsed, or in which the abnormality is composed and means for stopping the storage at the time of the disappearance. Further, the invention of claim 2 is the same as claim 1
In the invention described above, the abnormality detecting means detects an abnormality by comparing an average image of a plurality of images in the past with a current image, and outputs the abnormality signal.

[0007]

According to the present invention, the image data for a fixed time is always stored in the memory, and after the abnormality is detected, the video tape recorder is actually started and the image recording is started after the image recording is started. I tried to stop. As a result, all the necessary images including the video before the occurrence of the abnormality, that is, the images from the time when the abnormality is detected to when the video tape recorder is started up can be recorded without omission.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the abnormality monitoring device according to the embodiment. In this figure, a sync separation circuit 1 separates a composite video signal VD supplied from a video camera (not shown) into an image signal component and a sync signal component. Then, each signal component is converted into a digital signal, and the image data DT and the synchronization signal SY are output in synchronization with the clock CLK.

The abnormal phenomenon detection circuit 2 detects an abnormal phenomenon in the monitoring area based on the image data DT to detect an abnormal detection signal A.
B is output. The abnormality detection signal AB has a high level when an abnormal phenomenon is detected, and has a low level when the abnormal phenomenon is resolved. Here, the abnormal phenomenon refers to a phenomenon in which an object moves with respect to a stationary background image, or a phenomenon in which the contrast of the object changes. In addition,
Since it is an existing technology to detect an abnormal phenomenon, a detailed description thereof will be omitted, but the following processing is generally performed.

First, a moving average of each dot of these image data is calculated based on a plurality of image data sampled from a predetermined time before to the present,
Create an averaged screen. Although this screen is called a standard screen, the standard screen contains only the image corresponding to the background.
Next, the standard screen and the current screen are compared to obtain a difference screen. Then, only the image of the abnormal phenomenon from which the background portion is removed can be obtained on this difference screen. Then, when the image of the abnormal portion exceeds the threshold value (for example, when the image has a certain area or more), it is considered that the abnormal phenomenon is detected.

On the other hand, the address counter 3 generates an address AD for sequentially writing dots of the image data DT to the image data laminated memory 4 described later in synchronization with the clock CLK. When the address AD is generated, the synchronization signal SY is used for timing of horizontal / vertical synchronization.

The image data laminated memory 4 is a memory for accumulating the image data DT and is composed of frames of NS segments. The structure of this memory is shown in FIG.
Shown in As shown in this figure, this memory is logically arranged in a ring, and each frame is sequentially numbered from "0" to "NS-1". in short,
It is configured as an endless (loop-shaped) memory group. Here, in the present embodiment, the number of segments NS is set to "16", but it may be set to any value in consideration of cost.

Information for one screen of the image data DT is stored in each frame. Further, the storage in the frame is performed cyclically in the order of the frame numbers. That is, frame F
0, F1 ,. ． ． , F14, F15, F0, F1. ． ． As described above, the frame F15 is stored next to the frame F0.
It should be noted that the image data laminated memory 4 can be written only while a write signal WR, which will be described later, is at a high level, and further, image storage is stopped when the stop signal STP falls.

The field interval setting circuit 5 is a circuit for thinning the storage of the image data DT. This circuit determines a time interval Δτ for storing the image data DT in the image data laminated memory 4 and outputs a write signal WR of the image data laminated memory 4. Here, the time interval Δτ is calculated based on the synchronization signal SY and the variable recording interval FI set from the outside. For example, NTSC (National
According to the Television System Committee standard, the screen is updated at a rate of 60 frames per second for a monochrome image and 30 frames per second for a color image. Therefore, when handling a color image, the time interval Δτ is 1/3.
The recording interval FI is equal to 1 /
Specifies how many times 30 seconds to set. In this embodiment, the recording interval FI is set to "2", and 1 is set for 2 frames.
The image is recorded once, that is, at an interval of 1/15 second, and the above-mentioned write signal WR is at a high level only for one frame period of two frames.

The field segment setting circuit 6 is a ring counter and generates a frame number FN when writing the image data DT into the image data laminated memory 4.
The frame number FN takes an integer value in the range of "0 to (NS-1)" according to the configuration of the image data laminated memory 4.
Then, at the rising timing of the write signal WR, +
It counts up one by one cyclically. VTR
7 records the video signal VD on the video tape only while the abnormality detection signal AB is at the high level. Here, there is a delay of the rising time TD from the rising timing of the abnormality detection signal AB to the actual recording on the video tape. The value of the rising time TD is, for example, about 0.6 seconds, but this value changes each time the VTR 7 is activated.

The start / stop control circuit 8 uses the rising edge of the abnormality detection signal AB as a trigger to generate a stop signal STP.
To high level. Then, the stop signal STP is changed to the low level after the time required to write the frames of the number of effective segments NA has elapsed. here,
The effective segment number NA (≦ segment number NS) specifies the number of screens to be written in the image data laminated memory 4 starting from the time of detection of an abnormal phenomenon, and is a variable value set from the outside.

This will be described with reference to FIG. 2. The rising timing of the stop signal STP, that is, when an abnormal phenomenon is detected corresponds to the start point SP. After that, the image data DT is sequentially written into the frames of the number of effective segments NA (13 in this embodiment). The timing at which this writing is completed and the stop signal STP falls corresponds to the stop point EP. Therefore, (NS-NA) frames between the stop point EP and the start point SP record an image before occurrence of an abnormal phenomenon, so-called precursor phenomenon, and NA frames between the start point SP and the stop point EP. Stores an image after the occurrence of the abnormal phenomenon, that is, a so-called subsequent phenomenon.

The product of the segment number NA and the time interval Δτ is set to a value that is at least larger than the rising time TD of the VTR 7. By doing this, V
It can be guaranteed that all the images of the abnormal phenomenon until the TR 7 is actually activated are stored in the image data laminated memory 4. The data transfer circuit 9 sequentially transfers the image data DT stored in the image data laminated memory 4 to the storage device 10 by using the fall of the stop signal STP as a trigger.

Next, the operation of the abnormality monitoring device having the above configuration will be described. First, it is assumed that the value of the number of effective segments NA is determined to be "13" from the worst value of the rising time TD of the VTR7. In the initial state, the abnormal phenomenon detection circuit 2 has not detected any abnormality, the abnormality detection signal AB is at the low level, and the VTR 7 is in the stopped state.
It is also assumed that the frame number FN output by the field segment setting circuit 6 is initialized to "0".

Video signal VD output from the video camera
Is separated into image data DT and a sync signal SY by the sync separation circuit 1 and output as a digital signal. Then, by the synchronization signal SY, the field interval setting circuit 5 sets the write signal WR to the high level for one frame,
The image data laminated memory 4 becomes writable. In addition, the field segment setting circuit 6 outputs the write signal W
Frame number F is counted up at the rising edge of R
Output “1” to N. In this way, the image data DT of the first screen is written in the "frame F1" of the image data laminated memory 4.

When the writing for one screen is completed, the image data DT for the second screen is output from the sync separation circuit 1. At this time, the synchronization signal SY is output in the same manner as above, but the field interval setting circuit 5 sets the write signal WR to the high level only once in two screens, and therefore the write signal WR is set to the low level for this screen. And For this reason,
The second screen is not written in the image data laminated memory 4.

Next, when the third screen is displayed, the field interval setting circuit 5 sets the write signal WR to the high level again, so that the field segment setting circuit 6 counts up and the image data DT is written to the "frame F2". Be done. As described above, the image data DT is taken out once for every two screens, and the frames F1, F2 ,. ． ． F15, F0, F1 ,. ． ． It is written cyclically.

In this way, the frames F14, F15, F
It is assumed that 0 has been written (time is tSP) and it is at a time corresponding to the start point SP in FIG. At this time, when the abnormal phenomenon detection circuit 2 detects an abnormal phenomenon, the abnormality detection signal AB changes from the low level to the high level. As a result, the activation of the VTR 7 is instructed, and further the start / stop control circuit 8 operates. After this, the image data DT continues to be the frame F1,
F2. ． ． Is being written into. When time TD elapses from time tSP, for example, 0.7 seconds, VTR7
Starts recording the video signal VD. At this time, the processing of storing the image data DT in the image data laminated memory 4 is performed in parallel.

Writing of 13 frames is performed at "time tSP +
13/15 seconds ”(corresponding to the stop point EP in FIG. 2), the stop signal STP changes from the high level to the low level. With this fall as a trigger,
The image data laminated memory 4 stops storing the image data DT. Further, from this time, the data transfer circuit 9 starts the process of transferring the contents of the image data laminated memory 4 to the storage device 10. Then, when the abnormal phenomenon disappears and the abnormal detection signal AB falls after that, the VTR 7 stops recording the image on the video tape.

In this way, the three frames F14, F15, and F0 of the image data laminated memory 4 are recorded from a predetermined number of images before the abnormal phenomenon is detected, and the frames F1 to F13 are recorded. Images immediately after the abnormal phenomenon is detected are recorded in 13 frames. Also, V
An image 0.7 seconds (= rise time TD) after the abnormal phenomenon is detected is recorded in TR7. That is, from the time when the abnormal phenomenon is detected, “0.7 seconds to 13/15 (0.87)
The image during the second is the laminated memory 4 for image data and the VTR.
It has been recorded in both of 7. Thereafter, the images recorded in the image data laminated memory 4 and the VTR 7 are edited and transferred to another VTR to analyze the abnormal phenomenon.

[0026]

As described above, according to the present invention, the image data for a fixed time is always stored in the memory, and after the abnormality is detected, the video tape recorder actually starts up and the image recording is started. Since the image data is continuously recorded in the memory until that time, it is possible to obtain the effect that the image can be recorded without omission from the time of the abnormality detection until the start of the video tape recorder.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a logical configuration of a laminated memory for image data 4 according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Synchronous separation circuit, 2 ... Abnormal phenomenon detection circuit, 3 ... Address counter, 4 ... Laminated memory for image data, 5 ... Field interval setting circuit, 6 ... Field segment setting circuit, 7 ... VTR, 8 ... Start / stop control Circuit, 9
... data transfer circuit, 10 ... memory device

Claims (2)

[Claims] 1. An abnormality detecting means for detecting an abnormality by comparing a past image captured by a video camera with a current image captured by the video camera and outputting an abnormality signal, and the abnormality signal is output. A video tape recorder which is activated at a certain time point and records an output image of the video camera thereafter, and a memory of a fixed capacity in which the output image of the video camera is converted into digital image data and stored, at predetermined time intervals. After storing the image data of the certain capacity continuously captured, the memory in which the image data stored in the earliest is erased and new image data is stored, and after the time when the abnormal signal is output, Stop recording when the rise time of the video tape recorder is the same as or longer than the rise time, or when the abnormality disappears. An abnormality monitoring device comprising: 2. The abnormality detecting means detects an abnormality by comparing an average image of a plurality of past images with a current image, and outputs the abnormality signal. Anomaly monitoring device.