JP2000197038A - Monitor camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To store an image without deteriorating image quality in a monitor camera system, having plural monitor cameras in a wide range. SOLUTION: In this system, the analog video signal of the monitor camera 1 is made to be a digital compression image by a video capture device 3 and continuously stored in a ring buffer. The storage in the ring buffer is interrupted and started, the digital compression image is obtained from a capture controller 4 to the video capture device 3 via LAN and the digital compression image is stored, retrieved and extended by the controller 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surveillance system using a plurality of surveillance cameras, which digitally compresses an image taken by the surveillance camera, controls the image by a capture control device connected via a LAN, and stores a compressed image. The present invention relates to a surveillance camera system that performs expansion and display.

[0002]

2. Description of the Related Art In a conventional surveillance camera system, when accumulating images from a plurality of surveillance cameras, video signals output from the plurality of surveillance cameras are switched by a frame switcher to a long-time recorded video which is an image storage device. There are a recording method and a recording method for a long-time recording video as a video signal obtained by dividing a plurality of video signals into one screen by a screen dividing device. In the transmission of video signals from the surveillance camera to the long-time video recording, analog image signals are transmitted via a coaxial cable or the like.

In recent years, instead of long-time video recording using video tape as a medium, a hard disk or the like has been used as a medium.
Some image storage devices store digital images.

[0004]

In the above-mentioned prior art, when images of a plurality of surveillance cameras are stored using a screen dividing device, the images are more deteriorated than the image of one camera is stored in a long-time recorded video. I do. Further, since the analog video signal is transmitted by the coaxial cable, the video deterioration increases in proportion to the cable length. Therefore, in a large-scale store having a large number of cameras, the cable length is long and the image quality is deteriorated, so that the evidence ability is lacking.

In a large-scale surveillance camera system having a large number of cameras, one long recording video is required for each camera even if a frame switcher and a screen division device are used, and a plurality of long recording videos are required. For example, if there are multiple videotapes to search for the desired image,
It takes time to search and manage because the image data is dispersed, such as searching for each book separately. In addition, the cost is increased by increasing the number of long-time recorded videos.

It is an object of the present invention to provide a surveillance camera system having a plurality of surveillance cameras in a wide area so that image quality can be accumulated without deteriorating image quality.

[0007]

A surveillance camera system according to the present invention includes a capture device comprising a video capture device connected to a plurality of cameras, and a plurality of the capture devices are connected to a capture control device via a LAN. It is a system that can install a surveillance camera over a wide area by using means. Further, the video capture device,
An image without deterioration is obtained by digitally compressing analog video signals of a plurality of cameras for each camera and using means for continuously storing digital still images in a ring buffer.

When an event from a sensor is received by the video capture device, the event is reported to the capture control device via a LAN, and the capture control device interrupts the accumulation of the ring buffer of the video capture device for the camera. And confirming the congestion state of the LAN, and acquiring the digitally compressed image stored in the ring buffer, prevents the load on the LAN from increasing even if multiple events occur simultaneously. The transmission time of the image information can be minimized, and the control of the capture control device cannot keep up with the data and no data drop occurs.

By using means for accumulating and decompressing digitally compressed images in the capture control device, the amount of data stored in digitally compressed images of all surveillance cameras can be reduced, and retrieval processing performance can be improved.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of a surveillance camera system according to the present invention.

In FIG. 1, 1 is a camera having an analog video signal output, 2 is a non-voltage contact type sensor, and 3 is a digital converter which converts an analog video signal from one or more cameras into digital data, transmits the data, and sends it via a LAN. A video capture device 4 having a function to perform the operation is a capture control device.

Reference numeral 3 denotes a digital conversion unit 5 having a function of converting an analog video signal into digital data, a data compression unit 6 having a function of compressing digital data, and a data storage unit 7 for storing a compressed digitally compressed image. , A sensor receiving unit 8 for controlling sensor input, a network control unit 9 for controlling LAN, and an MPU 10 for controlling each unit of the video capture device 3. Video capture device 3
Has a plurality of channels so that one or more cameras 1 can be connected, a digital conversion unit 5 for converting an analog video signal into a digital video signal for each channel, a data compression unit 6 for compressing the digital video signal, a ring It has a data storage unit 7 which is a buffer. 11 is an event generator, 1
Reference numeral 2 denotes a storage device connected to the capture control device 4.

Next, the operation of the embodiment will be described. FIG. 2 is a sequence diagram between the video capture device 3 and the capture control device 4.

The capture control device 4 has a function capable of defining an association between the camera 1, the sensor 2 and each video capture device 3, and this association is defined as preparation.

The camera 1 always shoots a subject and outputs an analog video signal. This analog video signal is transferred to camera 1
Are received by the video capture device 3, converted into digital data by the digital conversion unit 5, a digitally compressed image of a still image is generated by the data compression unit 6, and the digitally compressed image is stored in the data storage unit 7. The processes of the digital conversion unit 5 and the data compression unit 6 are continuously performed at a constant interval for each channel, and a plurality of frames of digitally compressed images are stored in the data storage unit 7. When the digital compressed image to be stored exceeds the storage area, a ring buffer is realized by overwriting the oldest stored digital compressed image.

Examples of the sensor 2 include a glass break sensor and a door sensor. When the sensor 2 detects an abnormality and the sensor receiving unit 8 receives an event, the network control unit 9 notifies the capture control unit 4 of the sensor number, the event, and the like via the LAN (S1). The capture control device 4 stores the image up to the time when the event is received from the sensor 2 as a digital compressed image, by using a sensor number,
A request to the video capture device 3 that has notified the event (S1) to suspend the accumulation of the digital compressed image in the data accumulation unit 7 connected to the camera 1 corresponding to the sensor number (S1)
2) is transmitted via the LAN.

Upon receiving the interruption request (S2), the video capture device 3 interrupts the accumulation of the digitally compressed image in the data accumulation unit 7 connected to the camera 1 corresponding to the sensor number. At this time, if the request (S2) for interrupting the storage of the digital compressed image in the data storage unit 7 is transmitted with a delay, the digital compressed image before and after the event of the sensor 2 is received can be stored in the data storage unit 7. .

The capture control device 4 can manage all the cameras 1 and each video capture device 3 connected to the LAN and can grasp the congestion state of the LAN. Therefore, when the LAN is not congested, the sensor number and the event are notified ( S1) A request for transmitting a digitally compressed image of the data storage unit 7 connected to the camera 1 corresponding to the sensor number (S3) is transmitted to the video capture device 3 that has performed the process. Video capture device 3 that has received a digital compressed image transmission request (S3)
Transmits the digital compressed image of the data storage unit 7 connected to the camera 1 corresponding to the sensor number to the capture control device 4 (S4), and restarts the storage of the digital compressed image in the data storage unit 7. As shown in FIG. 3, the capture control device 4
Is a digital compressed image D from the video capture device 3.
1 and the sensor number D2, the event D3, the camera number D
4, adding the time D5 and the like, and accumulating them in a storage device connected to the capture control device 4. Specific examples of the storage device include a hard disk, an MO, a DVD-RAM, and a PD.

The capture control device 4 has a function of searching, decompressing, and displaying digital compressed images stored in the storage device. The capture control device 4 adds a sensor number D2, an event D3, a camera number D4, a time D5, etc. Since the compressed images are stored in one capture control device 4, it is possible to easily search when and which sensor has responded to even a surveillance camera system having a large number of cameras.

As described above, this is an event accumulation type surveillance camera system in which the images of the camera 2 before and after the event of the sensor 2 are stored in the storage device of the capture control device 4 via the LAN. Can also be performed.

In the above description, the event of the sensor 2 is transmitted from the video capture device 3 to the capture control device 4. If the connectable event generation device 11 is connected to the LAN to which the capture control device 4 is connected, the event It can be transmitted from the generation device 11 to the capture control device 4, and the received capture control device 4
Video capture device 3
To obtain a digitally compressed image of the specified camera number,
Can be accumulated. For example, some pachinko parlors have devices that monitor the status of each pachinko machine. This monitoring device is connected to a LAN as an event generation device 11, an illegal act on a pachinko machine is detected by the event generation device 11, and the camera number and the event capturing the illegal act are transmitted to the capture control device 4. , A digitally compressed image of the designated camera number can be obtained and stored.

In the case of a surveillance camera system, a high-quality image is required to increase the evidential ability. However, the amount of data is large in the compression in consideration of the high image quality of the video data. Further, when digital video data of a plurality of cameras 2 is simultaneously transmitted to the LAN, the data amount is too large, data is easily dropped on the LAN, and the possibility that necessary video data cannot be obtained increases. For this reason, when using a LAN, it is necessary to lower the image quality of video data, such as increasing the compression ratio. In the above-described embodiment, by controlling all the video capture devices 3 and the cameras 2 by the capture control device 4, the L
The congestion status of the AN can be grasped. By interrupting the storage of the digital compressed image in the data storage unit 7 and transmitting the digital compressed image when the LAN is not congested, it is possible to prevent the load on the LAN from increasing even with a high-quality compressed image. The transmission time of image information can be minimized, and the control of the capture control device 4 cannot keep up and data loss does not occur. However, since the data can be stored at one location of the capture control device 4, the retrieval is easier than in a distributed and stored environment. Further, since the number of video storage devices can be reduced, costs can be reduced.

[0023]

According to the present invention, a surveillance camera system having a plurality of surveillance cameras over a wide area can store images without deteriorating image quality.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a surveillance camera system according to one embodiment of the present invention.

FIG. 2 is a sequence diagram between a video capture device and a capture control device.

FIG. 3 is a diagram illustrating a storage format of a digital compressed image.

[Explanation of symbols]

1 ... camera, 2 ... sensor, 3 ... video capture device,
4 capture control device, 5 digital conversion unit, 6 data compression unit, 7 data storage unit, 8 sensor reception unit, 9
... Network control unit, 10 ... MPU, 11 ... Event generator, 12 ... Storage device, S1 ... Sensor number, event notification, S2 ... Digital compressed image storage interruption request, S3 ... Digital compressed image transmission request, S4 ... Digital compression Image transmission, D1: Digitally compressed image, D2: Sensor number, D3
... Sensor event, D4 ... Camera number, D5 ... Time.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisashi Matsumura 810 Shimo-Imaizumi, Ebina-shi, Kanagawa PC Division of Hitachi, Ltd. (72) Inventor Masahiro Oshima 810 Shimoimaizumi, Ebina-shi, Kanagawa F-term in PC Division, Hitachi, Ltd.F-term (reference)

Claims (3)

[Claims] A plurality of video capture devices each connected to a plurality of cameras; and a capture control device connected to the plurality of capture devices via a LAN. Means for taking the analog video signals from the plurality of cameras into a video capture device and compressing them into digital still images; and inputting the analog video signals output from the plurality of cameras and ringing the digital still images compressed at regular intervals for each camera. Means for continuously capturing images stored in a buffer, and means for transmitting the plurality of digitally compressed images stored in the ring buffer to the capture control device, wherein the capture control device is Start, stop, and transmit the image storage to the camera via the LAN according to the status of the LAN. It said means for instructing the video capture device, storing the digitally compressed images, surveillance camera system characterized by a means for expansion processing. 2. The video capture device according to an instruction from the capture control device, fetches a digital compressed image from a digital compressed image stored in the ring buffer before a timing of an image storage interruption request and captures the digital compressed image. The surveillance camera system according to claim 1, wherein the surveillance camera system transmits the result to a control device. 3. The video capture device includes: means for reporting an event from one of a connected sensor and an event generation device connected to the LAN to the capture control device; and an event responding to an instruction from the capture control device. Means for extracting a digitally compressed image before the timing of occurrence and transmitting the digitally compressed image to the capture control device.