JP2008225947A - Video monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically generate a warning event with respect to the abnormal occurrence like a disaster without providing any sensor. <P>SOLUTION: This video monitoring system is configured of monitor cameras 11 to 13 for acquiring the video information of a monitor area; and video input devices 21 to 23 for generating video data by encoding the video information acquired by the monitor camera 1 by an information compression method based on the correlation of time directions. Then, this video monitoring system is provided with an information quantity monitoring device 1 for generating a warning event when the information quantity of video data generated every moment by the video input devices 21 to 23 exceeds a preset prescribed threshold. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a video monitoring system for monitoring video data of a surveillance camera or the like transmitted mainly via a network, and more particularly to a video monitoring system for recording and displaying.

  As described in Patent Document 1, in a conventional video monitoring system, when a video of a monitoring area acquired by a monitoring camera is monitored visually or by a sensor, an abnormality in the monitoring area, for example, occurrence of a disaster is detected In addition, video information was recorded.

JP 2006-203342 A

  However, in visual monitoring, it is necessary to monitor video in a plurality of video monitoring systems, and there has been a problem that detection of an abnormality such as a disaster fails due to a human error such as missing the video. Furthermore, the monitoring by the sensor has a problem that it is expensive.

  The present invention has been made to solve the above-described problems, and an object thereof is to automatically generate a warning event for occurrence of an abnormality such as a disaster without providing a sensor.

  According to a first aspect of the present invention, there is provided a video monitoring system that encodes a monitoring camera that acquires video information of a monitoring area, and the video information acquired by the monitoring camera by an information compression method based on a correlation in a time direction. And a video input device for generating video data. An information amount monitoring device is provided that generates a warning event when the information amount of the video data generated every moment by the video input device exceeds a predetermined threshold value set in advance.

  According to a fifth aspect of the present invention, there is provided a video monitoring system that encodes a monitoring camera that acquires video information of a monitoring area and the video information acquired by the monitoring camera by an information compression method based on a correlation in a time direction. And a video input device for generating video data at a constant encoding rate. And an information amount monitoring device that generates a warning event when a quantization level of a quantization parameter of the video data generated every moment by the video input device becomes coarser than a predetermined threshold value set in advance.

  According to the video monitoring system of the present invention, it is possible to automatically generate a warning event for occurrence of an abnormality without providing a sensor.

<Embodiment 1>
FIG. 1 is a block diagram showing a configuration of a video monitoring system according to the present embodiment. The video monitoring system according to the present embodiment includes an information amount monitoring device 1, a network 2, a recording device 3, a video control device 4, a video display device 5, monitoring cameras 11 to 13, and a video input device 21. To 23. The information amount monitoring device 1, the recording device 3, the video control device 4, and the video input devices 21 to 23 are connected to each other via the network 2.

  The monitoring cameras 11 to 13 acquire video information of the monitoring area. In the present embodiment, the monitoring cameras 11 to 13 acquire video information of a monitoring area that is a fixed monitoring target. As shown in FIG. 1, each of the monitoring cameras 11 to 13 is connected to each of the video input devices 21 to 23, and outputs the acquired video information to the video input devices 21 to 23.

  Each of the video input devices 21 to 23 encodes the video information acquired by each of the monitoring cameras 11 to 13 by an information compression method based on the correlation in the time direction to generate video data. In this embodiment, MPEG4 is used as a method for compressing video information based on the correlation in the time direction. In addition, the video input devices 21 to 23 encode video information corresponding to the entire monitoring area acquired by the monitoring cameras 11 to 13.

  A state in which the video input devices 21 to 23 compress the information of the video information acquired by the monitoring cameras 11 to 13 using MPEG4 will be described with reference to FIG. In FIG. 2, 16 frames of video information F1 to F15, F1 'are shown. In the present embodiment, the video input devices 21 to 23 compress the information of 15 frames of video information F1 to F15 as one unit.

  The first frame F1 is a frame that is encoded within the frame without using the correlation in the time direction, and is called an intra frame. In the encoding of an intra frame, first, video information for one frame is divided into a plurality of blocks, and discrete cosine transform (DCT) is performed on the video information divided in units of blocks. Then, the video input devices 21 to 23 generate video data by quantizing and encoding the data after DCT conversion with a fixed quantization parameter.

  Frames F4, F7, F10, and F13 are frames that are encoded using only prediction from a past frame, that is, forward prediction, and are called forward prediction frames. Frames F2, F3, F5, F6, F8, F9, F11, F12, F14, and F15 are frames encoded using prediction from the preceding and subsequent frames, that is, bidirectional prediction. be called.

  The frame F4, which is a forward prediction frame, is encoded by predicting from the frame F1, for example. The frame F2, which is a bidirectional prediction frame, is encoded by predicting from the frame F1 and the frame F4, for example.

  In the encoding of the forward and bidirectional prediction frames, the video information for one frame is divided into a plurality of blocks, the block having the smallest difference error from the video information of the prediction target frame is selected, and the difference signal is selected. DCT is performed on. Then, the video input devices 21 to 23 generate video data by quantizing and encoding the data after DCT conversion with a fixed quantization parameter.

  By such an information compression method based on the correlation in the time direction, the video input devices 21 to 23 encode video information acquired by the monitoring cameras 11 to 13 to generate video data from time to time. The video input devices 21 to 23 transmit the video data to the information amount monitoring device 1 via the network 2. In the present embodiment, the video input devices 21 to 23 also transmit video data to the recording device 3 and the video control device 4 via the network 2.

  The information amount monitoring device 1 receives video data from the video input devices 21 to 23 via the network 2. The information amount monitoring device 1 generates a warning event when the information amount of the video data generated every moment by the video input devices 21 to 23 exceeds a predetermined threshold value set in advance. In the present embodiment, an abnormality occurs when any of the information amount of the video data generated by each of the video input devices 21 to 23 exceeds a predetermined threshold set in advance for each of the video data, Determine that a disaster has occurred.

  The video control device 4 receives video data from the video input devices 21 to 23 via the network 2. Then, the video control device 4 performs control to record the video data generated by the video input devices 21 to 23 in the recording device 3 around a predetermined time from the timing when the warning event occurs in the information amount monitoring device 1. Note that the control method of the recording apparatus 3 is the same as the conventional control method.

  Further, the video control device 4 performs control to display a predetermined warning, for example, a disaster occurrence warning, on the video display device 5 in response to the occurrence of a warning event in the information amount monitoring device 1. In the present embodiment, the video control device 4 further controls to decode the video data generated by the video input devices 21 to 23 and display the decoded video on the video display device 5. The video display device 5 is a display device for monitoring, and corresponds to, for example, a large video display device.

  The operation of the video surveillance system according to the present embodiment having the above configuration will be described. First, the monitoring cameras 11 to 13 acquire video information of a monitoring area to be monitored. Then, the video input devices 21 to 23 generate video data by encoding the video information acquired by the monitoring cameras 11 to 13 by an information compression method based on the correlation in the time direction. The video input devices 21 to 23 transmit video data to the information amount monitoring device 1 via the network 2.

  The information amount monitoring device 1 determines that an abnormality such as a disaster has occurred when the information amount of the video data generated every moment by the video input devices 21 to 23 exceeds a predetermined threshold value, and warns. Generate an event. The operation of the information amount monitoring device 1 will be described with reference to FIG.

  When encoding using forward prediction and bi-directional prediction, if the quantization parameter is fixed, the amount of information of video data increases as the difference in video information between the previous and subsequent frames increases.

  In normal times, the video information of the fixed monitoring area acquired by each of the monitoring cameras 11 to 13 hardly changes, so there is almost no difference between the preceding and succeeding frames. In this case, as shown in FIG. 3, the information amount of the video data corresponding to the forward prediction frame and the bidirectional prediction frame is small. Then, since the information amount of the video data does not exceed a predetermined threshold value set in advance, for example, Vt shown in the figure, the information amount monitoring device 1 does not determine that an abnormality, for example, a disaster has occurred.

  On the other hand, when an abnormality such as a disaster occurs, the situation of the fixed monitoring area changes greatly, and the video information acquired by each of the monitoring cameras 11 to 13 changes greatly. Therefore, the difference between the previous and subsequent frames increases. In this case, as shown in FIG. 3, the information amount of the video data corresponding to the forward prediction frame and the bidirectional prediction frame increases. Then, the information amount of the video data exceeds a predetermined threshold value Vt set in advance, and the information amount monitoring device 1 determines that an abnormality, for example, a disaster has occurred, and generates a warning event.

  The video control device 4 performs control to display a predetermined warning, for example, a disaster occurrence warning, on the video display device 5 in response to the occurrence of a warning event in the information amount monitoring device 1. The video control device 4 performs control to record the video data generated by the video input devices 21 to 23 in the recording device 3 around a predetermined time from the timing when the warning event occurs in the information amount monitoring device 1.

  The video monitoring system according to the present embodiment performing the operation as described above monitors the information amount of video data encoded by the information compression method based on the correlation in the time direction, as in MPEG4. For this reason, it is possible to automatically generate a warning event for occurrence of an abnormality, for example, a disaster without providing a sensor in the monitoring area. Further, in such a video monitoring system, a warning event can be generated even if video information acquired from the plurality of monitoring cameras 11 to 13 is not displayed on the video display device 5 at all.

  In addition, since the video input devices 21 to 23 transmit the video data to the information amount monitoring device 1 via the network 2, a warning event can be generated simultaneously in a plurality of remote systems.

  In this embodiment, an example in which video information is compression-encoded by MPEG4 has been described. However, the present invention is not limited to this, and an information compression method based on a correlation in the time direction, for example, MPEG2 may be used. Moreover, although the structure which provided the three monitoring cameras 11-13 was shown, as long as there are one or more monitoring cameras, how many may be sufficient. In addition, the video control device 4 normally prevents video from being displayed on the video display device 5, and when the information amount monitoring device 1 generates a warning event, the video control device 4 displays the video combined with the video data. 5 may be controlled to start displaying. In this embodiment, the video information is compressed in units of 15 frames in FIG. However, it is not necessary to have 15 frames, and the same effect can be obtained by compressing video information in units of arbitrary plural frames.

<Embodiment 2>
In the first embodiment, the video input devices 21 to 23 perform DCT on video information in units of blocks, and then quantize the video data after DCT conversion using a fixed quantization parameter. For this reason, the information amount of the video data changes corresponding to the difference between the previous and subsequent frames.

  In the present embodiment, the video input devices 21 to 23 encode the video information acquired by the surveillance cameras 11 to 13 by the information compression method based on the correlation in the time direction as in the first embodiment. Unlike the first embodiment, video data having a constant encoding rate is generated. That is, unlike the first embodiment, the video input devices 21 to 23 change the quantization level of the quantization parameter of the video data from time to time, thereby making the information amount of the video data transmitted over the network 2 constant. keep.

  The information amount monitoring device 1 receives the quantization level information of the quantization parameter together with the video data generated every moment by the video input devices 21 to 23. Then, the information monitoring device 1 generates a warning event when the quantization level of the quantization parameter of the video data generated every moment by the video input devices 21 to 23 becomes coarser than a predetermined threshold value set in advance. To do. Other configurations are the same as those in the first embodiment.

  The operation of the video surveillance system according to the present embodiment having the above configuration will be described with reference to FIG. The video input devices 21 to 23 acquire the video information of the monitoring area acquired by each of the monitoring cameras 11 to 13.

  In normal times, the video information of the fixed monitoring area acquired by each of the monitoring cameras 11 to 13 hardly changes. In this case, the video input devices 21 to 23 keep the quantization level of the quantization parameter fine. As shown in FIG. 4, the quantization level of the normal quantization parameter does not exceed a predetermined threshold value, so the information monitoring device 1 does not generate a warning event.

  On the other hand, when an abnormality such as a disaster occurs, the situation of the fixed monitoring area changes greatly, and the video information acquired by each of the monitoring cameras 11 to 13 changes greatly. In order to make the information amount of the video data constant with respect to such a change in the video information, the video input devices 21 to 23 make the quantization level of the quantization parameter coarser than usual. As shown in FIG. 4, since the quantization level of the quantization parameter when an abnormality such as a disaster occurs exceeds a predetermined threshold, the information monitoring device 1 generates a warning event.

  As described above, the video monitoring system according to the present embodiment differs from the first embodiment in which the video data information amount is variable, instead of keeping the video data information amount constant, the quantization level of the quantization parameter. Is variable. A warning event is generated when the quantization level of the quantization parameter exceeds a predetermined threshold. Therefore, it is possible to automatically generate a warning event for occurrence of an abnormality such as a disaster without providing a sensor in the monitoring area.

  Note that the quantization level of the quantization parameter of MPEG4 of the present embodiment may change even in the video information of each frame within 15 frames. Therefore, in the present embodiment, monitoring may be performed using an average value of quantization levels of quantization parameters for 15 frames of video information F1 to F15.

<Embodiment 3>
In the first and second embodiments, the video input devices 21 to 23 generate video data by encoding video information corresponding to the entire monitoring area acquired by the monitoring cameras 11 to 13. However, for example, when there is an image of trees moving under the influence of wind or the like in the hatched portion in the monitoring area 6 shown in FIG. 5, the difference in image information between the previous and next frames is large despite the normal time. In some cases, a warning event occurs.

  Therefore, in the present embodiment, video data is monitored by selecting video information of a part of the monitoring area acquired by the monitoring cameras 11 to 13, for example, a part of the monitoring area indicated by a dotted frame in FIG. 5. .

  In such a configuration, even if a leaf fluctuates due to wind in the shaded portion, it does not affect the change in the video information of a part of the monitoring area indicated by the dotted frame in FIG. As described above, the video monitoring system according to the present embodiment can reliably generate a warning event for occurrence of an abnormality, for example, a disaster, avoiding external influences such as weather and wind.

1 is a block diagram illustrating a configuration of a video surveillance system according to Embodiment 1. FIG. 6 is a diagram illustrating an operation of the video monitoring system according to Embodiment 1. FIG. 6 is a diagram illustrating an operation of the video monitoring system according to Embodiment 1. FIG. 6 is a diagram illustrating an operation of a video surveillance system according to Embodiment 2. FIG. FIG. 10 is a diagram illustrating an operation of a video surveillance system according to Embodiment 3.

Explanation of symbols

  1 Information amount monitoring device, 2 network, 3 recording device, 4 video control device, 5 video display device, 6 monitoring area, 11-13 monitoring camera, 21-23 video input device, F1-F15, F1 ′ frame.

Claims (6)

A surveillance camera that acquires video information of the surveillance area;
A video input device that generates video data by encoding the video information acquired by the monitoring camera using an information compression method based on a correlation in a time direction;
An information amount monitoring device that generates a warning event when the information amount of the video data generated momentarily by the video input device exceeds a predetermined threshold set in advance.
Video surveillance system. The video input device transmits the video data to the information monitoring device via a network;
The video surveillance system according to claim 1. A video display device;
A video control device that performs control to display a predetermined warning on the video display device in response to the occurrence of the warning event in the information amount monitoring device;
The video surveillance system according to claim 1 or 2. A recording device;
A video control device that performs control to record the video data generated by the video input device in the recording device around a predetermined time from the timing when the warning event occurs in the information amount monitoring device;
The video surveillance system according to claim 1 or 2. A surveillance camera that acquires video information of the surveillance area;
A video input device that encodes the video information acquired by the monitoring camera by an information compression method based on a correlation in a time direction to generate video data at a constant encoding rate;
An information amount monitoring device that generates a warning event when a quantization level of a quantization parameter of the video data generated momentarily by the video input device becomes coarser than a predetermined threshold value set in advance.
Video surveillance system. Monitoring the video data by selecting the video information corresponding to a part of the monitoring area acquired by the monitoring camera;
The video surveillance system according to any one of claims 1 to 5.

Images