JP2009171295A - Video network system and transmission controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control network load without changing existing cameras and video storage devices. <P>SOLUTION: A video network system includes a storage device 4 which stores images photographed by a plurality of cameras, a request converter 3 which converts an address and a port that are included in an image request transmitted from the storage device to the camera and transfers the image request to the camera, and converts an address and a port that are included in a reply message transmitted from the camera to the storage device and transfers the reply message to the storage device 4, and a transmission controller 20 which specifies either of the cameras to transfer an image request based on port information included in the image request transferred by the request converter and transfers the image request, and converts an address and a port that are included in a reply message transmitted from the camera responding to the image request and transfers the reply message to the request converter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a video network system including a plurality of cameras.

  With the widespread use of IP-capable imaging devices such as Web cameras, it has become possible to construct a wide-area and large-scale monitoring system using an IP network. However, if a large number of cameras and video storage devices are simply IP-connected, an efficient monitoring system cannot be configured due to insufficient bandwidth and / or load concentration. For this reason, it is necessary to perform bandwidth control based on information priority. There are the following three methods for realizing this.

  The first is a method of incorporating a bandwidth control function into a camera and a video storage device. However, it is difficult to additionally introduce a bandwidth control function to an existing system constructed using inexpensive commercial products. Even if it is possible to incorporate a bandwidth control function, it is necessary to change settings for a large number of devices when a new prioritization method is added.

  Second, it is a method of introducing bandwidth control below the IP layer. This has the advantage that it can be introduced transparently, but it is difficult to introduce bandwidth control based on priority information at the content level that can be identified only in layer 4 or higher.

  Third, there is a method of explicitly controlling the bandwidth by introducing a layer 7 network processing device such as a Web proxy. This has the advantage that no change is required on the camera side that receives the request, but a program change occurs on the storage device side that issues the request.

  With either method, it has been difficult to realize wide-area and large-scale monitoring system bandwidth control.

For example, a technique disclosed in Patent Document 1 is known as a device that performs transmission control with a device on a communication path. This introduces a delay in replying to a malicious mail at the time of mail transfer, thereby enabling normal mail to be transferred at a high response speed while reducing the response speed to the malicious mail.
JP 2003-173315 A

  However, in the conventional technology as described above, when video data (frame images) from a large number of cameras is registered in the video storage device, the load on the network for transferring the data increases, and the capacity of the storage device of the video storage device Will increase.

  In addition, when the bandwidth control function is incorporated into the existing camera and the video storage device as described above, it is not possible to introduce the bandwidth control function additionally to the existing system constructed by using a commercially available product that is inexpensive. There is a problem that capital investment becomes excessive. In particular, when the number of cameras becomes a large number such as hundreds or thousands, there is a problem that it takes a lot of labor and cost to make changes to the camera itself.

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to suppress a load on a network without changing an existing camera and a video storage device.

  The present invention includes a plurality of camera devices that capture images, a storage device that stores images captured by the camera device, and a network that connects the camera devices and the storage device, and the storage device is the camera device. In the video network system that transmits an image request to the storage device when the camera device receives the image request, the camera device is installed between the network and the storage device. The image request transmitted to the camera device is received, the address and port included in the image request are converted, the image request is transferred to the camera device side, and a reply message transmitted from the camera device to the storage device is transmitted. Receiving, converting the address and port included in the reply message, and then sending the reply message to the storage device. A request conversion device that transfers to the network, and a camera that is installed between the network and the camera device, receives the image request transferred by the request conversion device, and transfers the image request from information on a port included in the image request The device is specified, the image request is transferred to the specified camera device, the reply message transmitted by the camera device in response to the image request is received, and the address and port included in the reply message are converted. And a transmission control device for transferring to the request conversion device.

  When the request conversion device receives an image request from the storage device, the request conversion device converts the destination address included in the image request into the address of the transmission control device instead of the address of the camera device set by the storage device. Then, a value corresponding to the address of the camera device is set in the destination port, the transmission source address of the image request is converted into the address of the request conversion device on behalf of the storage device, and then the transmission control of the image request is performed. When a reply message is received from the transmission control device, the destination address included in the reply message is converted into the address of the storage device, and the value of the destination port included in the reply message is transmitted correspondingly. The reply message is transferred to the storage device after being converted into the original address, and the transmission control device Identifies a camera device that forwards the image request from a destination port included in the image request received from the request conversion device, forwards the image request to the identified camera device, and responds to the image request according to the image request. Upon receiving the reply message transmitted by the camera device, the destination address included in the reply message is converted into the address of the request conversion device, and a value corresponding to the source address included in the reply message is set in the destination port. And then forwarded to the request conversion device.

  Further, when the camera device receives the image request, the camera device transmits a predetermined number of images as a reply message, and the transmission control device, based on the information on the camera device to be prioritized received from another computer, The priority of the reply message to be transferred to the request conversion apparatus is set for each camera apparatus, and the timing for transferring the received reply message is changed based on the priority.

  Therefore, according to the present invention, by performing frame rate control (bandwidth control) based on the priority of the reply message, it is possible to transfer an image with the minimum necessary bandwidth, and even in a system having a large number of camera devices. It is possible to suppress an excessive load on the network. Furthermore, when applied to an existing system, it is only necessary to insert the request conversion device and the transmission control device between the camera measures and the storage device, so that the introduction cost and labor can be reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an example of a network video monitoring system to which the present invention is applied. FIG. 2 is a block diagram showing an outline of communication between the components of the network video monitoring system shown in FIG.

  In FIG. 1, the network video monitoring system includes a camera group 2-0 and 2-1 including a plurality of cameras 220, a center 1 that controls the plurality of cameras 220 and displays an image of a desired camera 220, and a center 1 And a network 100 that connects each of the camera groups 2-0 and 2-1, and a sensor network 8 that is connected to the sensor information conversion device 7 of the center 1 and transfers information (sensor information) from the sensor node. The

  In this network video monitoring system, a plurality of cameras 220 are installed in a building or the like, an administrator or a monitor of the monitoring center 1 monitors images of the plurality of cameras 220, and images of each camera 220 are stored in the storage device 4. It will be stored.

  The monitoring center 1 includes a display PC (computer) 5 that displays thumbnail images of a plurality of cameras 220 and displays images of a desired camera 220 as high-definition images, and is displayed by an administrator (or a monitor). A thumbnail image or a high definition image displayed on the input / output device 50 of the PC 5 is monitored. The display PC 5 displays an image of the camera 220 corresponding to the position of the sensor node on the input / output device 50 based on a preset event from the sensor node. A sensor node is fixed at a predetermined position and is associated with a predetermined camera 220, and an image of the camera 220 is displayed on the display PC 5 from an event of the sensor node, thereby passing a person or an object. Can be monitored. The display PC 5 can display the image of the camera 220 designated by the administrator by operating the input / output device 50 with high definition.

  In order to realize the above-described functions, the monitoring center 1 includes a display PC 5 that displays images, a storage device 4 that requests and stores images from the camera groups 2-0 and 2-1, and a camera group 2-0, A search PC (computer) 6 that acquires image thumbnails and feature values from the image 2-1, and distributes them to the display PC 5, a request conversion device 3 that converts image requests from the storage device 4 as described later, and a sensor network 8 includes a sensor information conversion device 7 that converts information from 8 as described later and transmits sensor information associated with the identifier of the camera 220. Details of each part will be described below.

<Configuration of camera group>
The monitoring center 1 manages a plurality of camera groups 2-0 and 2-1, and each camera group is set for each predetermined area (for example, each floor) such as a building or for each camera 220. One camera group 2-0 and 2-1 includes a plurality of cameras 220 and one transmission control device 20. In the following description, since the configurations of the camera groups 2-0 and 2-1 are the same, the same reference numerals are assigned to the same components, and redundant descriptions are omitted.

  The camera 220 installed at a predetermined position captures and outputs an image (moving image) with a predetermined resolution at a predetermined frame rate. The camera 220 is connected to a camera PC (computer) 210.

  The camera PC 210 is a computer having a CPU, a memory, and a communication interface. As shown in FIG. 2, the storage device 4 of the monitoring center 1 frame-by-frame the moving image captured by the camera 220 in response to a request from the storage device 4. Send to. Therefore, the camera PC 210 transmits the latest one frame (image) to the storage device 4 only when there is an image request from the storage device 4, and the generation and characteristics of thumbnail images described later for the other frames. Discard when the amount extraction is complete.

  Further, as shown in FIG. 2, the camera PC 210 generates a thumbnail image from the image captured by the camera 220, extracts the feature amount of the image, and searches the thumbnail PC and the feature amount for the search PC of the monitoring center 1. (Computer) Send to 5. The thumbnail image is obtained by reducing the resolution of a moving image taken by the camera 220. For example, when the camera 220 outputs an image having a resolution of 640 × 480 dots (VGA), the camera PC 210 uses 128 × as a thumbnail image. A 96-dot image is generated. Further, the camera PC 210 extracts the feature amount of the image from the image captured by the camera 220 by a known method such as edge detection or contour detection. In the following description, an image having a higher resolution than the resolution or thumbnail image of the original image of the camera 220 is referred to as a high-definition image.

  Information transmitted from each camera PC 210 to the monitoring center 1 and information from the monitoring center 1 to each camera PC 210 or camera 220 are transferred via the transmission control device 20.

  Here, a predetermined identifier (for example, an IP address) is assigned to each camera PC 210 in advance, and the monitoring center 1 identifies the camera 220 based on the IP address.

  The storage device 4 designates the IP address of the camera PC 210 that acquires the image and transmits an image request to the request conversion device 3. The request conversion device 3 converts the destination of the image request from the storage device 4 into an address and a port number of the transmission control device 20 of each camera group, as will be described later, and transmits it to the network 100. The storage device 4 polls all the camera PCs 210 and transmits an image request for each camera PC 210 to the request conversion device. However, two or more requests are not issued to one camera PC 210 in parallel.

  When the transmission control apparatus 20 receives an image request from the request conversion apparatus 3 via the network 100, the transmission control apparatus 20 identifies the camera PC 210 from the port number of the image request and transfers the image request to the identified camera PC 210. For this reason, the camera PC 210 includes a transfer destination table 230 indicating the correspondence between the port number and the camera PC 210. The transfer destination table 230 is set in advance, and is set as shown in FIG. FIG. 5 will be described later.

  The camera PC 210 returns one frame of the latest image (high definition image) in response to the image request from the transmission control device 20. The transmission control device 20 converts the message including the image received from the camera PC 210 into a port number that identifies the camera PC 210 and transmits the message to the request conversion device 3. The request conversion device 3 converts the port number of the received image into the IP address of the camera PC 210 and transmits it to the storage device 4. The storage device 4 specifies the camera PC 210 from the IP address of the transmission source of the received image and stores the image.

  The transmission control apparatus 20 places a predetermined number of camera PCs 210 under its control, transfers the image request transferred from the request conversion apparatus 3 to the camera PC 210, receives a reply message for the image request, and returns it to the request conversion apparatus 3. As will be described later, the frame rate is controlled based on the priority and the sensor information. In order to control the priority for transferring the reply message, the transmission control device 20 includes a priority history table 240 shown in FIG. FIG. 6 will be described later.

  Further, the transmission control device 20 is placed on the monitoring target base side (that is, the camera group side), and the request conversion device 3 is placed on the monitoring center 1 side that performs aggregated monitoring, and is connected to the wide area network 100 in the meantime. As a result, the traffic flowing through the network 100 can be reduced.

  In the present embodiment, the configuration in which the camera PC 210 and the camera 220 are independent is shown, but the configuration in which the camera PC 210 and the camera 220 are integrated may be used.

<Configuration of monitoring center>
Next, components of the monitoring center 1 will be described below with reference to FIGS. 1 and 2.

  The storage device 4 is configured by a computer including a CPU, a memory, a communication interface, and a storage device. The storage device 4 places a large number of camera PCs 210 under management, and transmits an image request to each camera PC 210 to acquire a high-definition image. At the same time, a high-definition image is returned in response to a stored image acquisition request from the display PC.

  The sensor information conversion device 7 is constituted by a computer having a CPU, a memory, and a communication interface, and controls transmission of information sent from the sensor network 8 including the infrared transmission node 820, the name tag sensor 810, and the wireless base station 80. The message (sensor information) is transmitted to the device 20 and the search PC 6 after being converted into a message format and a transmission procedure that can be interpreted.

  The sensor information conversion device 7 includes a sensor-camera management table 70 that identifies the identifier of the camera PC 210 corresponding to the sensor node from the identifier of the sensor node. The sensor-camera management table 70 is a table in which a preset IP address of the camera PC 210 is set for an identifier of a fixed node among sensor nodes. For example, a person or an object passing near the fixed node can be photographed. The IP address of the camera PC 210 connected to the correct camera 220 is set.

  As shown in FIG. 2, when receiving an event from a name tag sensor 810, which will be described later, via the wireless base station 80, the sensor information conversion device 7 refers to the sensor-camera management table 70 and refers to the identifier (ID) of the infrared node 820. ) To identify the IP address of the camera PC 210 and transmit this IP address to the transmission control apparatus 20 as a priority camera ID indicating that the image should be prioritized when transferring the image. The sensor information conversion device 7 transmits an event from the name tag sensor 810 to the search PC 6 when transmitting the priority camera ID to the transmission control device 20. In addition to the priority camera ID, the sensor information conversion device 7 also transmits the identifier (name tag ID) of the name tag sensor 810 that transmitted the event and the type of the event as sensor information to the transmission control device 20 and the search PC 6. . The event type is the type of information detected by the fixed node, such as detection (approach) of the name tag sensor 810 or disappearance (detachment) of the detected name tag sensor 810.

  The search PC 6 is configured by a computer including a CPU, a memory, a communication interface, and a storage device, and stores the feature amount and thumbnail image of the image from the camera PC 210 and the sensor information received from the sensor information conversion device 7, and the display PC 5 Detection information (sensor information from the sensor network) and a thumbnail image are sent.

  The request conversion device 3 includes a CPU, a computer having a memory and a communication interface, is arranged on a communication path between the storage device 4 and the camera PC 210, and relays an image request from the storage device 4 to the camera PC 210. In addition, the transmission source and transmission destination of the message are changed so as to pass through the transmission control device 20, and the transmission source and transmission destination of the message from the transmission control device 20 toward the storage device 4 are changed.

  The request conversion device 3 converts the destination (the IP address of the camera PC 210) included in the image request from the storage device 4 into the IP address and port number of the transmission control device 20 of each camera group, and the transmission source is the request conversion device 3. The message replaced with is transmitted to the transmission control device 20. Further, the request conversion device 3 converts the destination included in the reply (image) from the transmission control device 20 to the storage device 4, and sends the message converted to the IP address of the camera PC 210 included in the reply to the storage device 4. Send. Therefore, the request conversion device 3 includes an address conversion table 30 for converting the IP address and port number of the camera PC 210. The address conversion table 30 is configured as shown in FIG. 4 and will be described in detail later.

  The display PC 5 is configured by a computer having a CPU, a memory, and a communication interface, and displays thumbnail images of a plurality of cameras 220 and desired camera 220 images on the input / output device 50 as high-definition images. The input / output device 50 includes a display, a keyboard, a mouse, and the like.

  The display PC 5 notifies the transmission control device 20 of the identifier (priority camera ID) of the camera PC 210 designated by the administrator or the monitor by operating the input / output device 50 as the camera PC 210 that prioritizes the frame rate. Based on this notification, the transmission control device 20 updates the priority history table 240 of the designated camera PC 210.

  When the camera PC 210 to be displayed by the administrator or the like is designated on the display PC 5, as shown in FIG. 2, the display PC 5 transmits the identifier of the camera PC 210 to the transmission control device 20 as the priority camera ID, and the high definition of the priority camera ID. The image is requested to the storage device 4. When the storage device 4 receives the image from the camera PC 210 requested from the display PC 5, it transfers the image to the display PC 5. Thereby, the display PC 5 can display an image taken by the camera 220 of the designated camera PC 210.

  In addition, when the sensor information conversion device 7 receives the sensor information from the search PC 6 that receives the event, the display PC 5 instructs the storage device 4 to acquire the image of the priority camera ID included in the sensor information.

<Configuration of sensor network>
Next, the sensor network 8 will be described. In FIG. 1, the sensor network 8 includes a radio base station 80 connected to the sensor information conversion apparatus 7 and a sensor node connected to the radio base station 80 via the radio network 800.

  As a sensor node of this embodiment, an example in which a fixed node fixed at a predetermined position and a mobile node attached to a person or an object is shown. In FIG. 1, the sensor network 8 includes an infrared node 820 that transmits a preset identifier from an infrared transmitter as a fixed node. The sensor network 8 includes a name tag sensor 810 that transmits the identifier received from the infrared node 820 as a mobile node to the radio base station 80.

  FIG. 13 shows the configuration of the name tag sensor 810 and the infrared node 820. The infrared node 820 includes an ID storage unit 822 that stores a preset identifier, an infrared communication unit 823 that transmits the identifier, and a wireless communication unit 821 that communicates with the wireless base station 80.

  The name tag sensor 810 includes an infrared communication unit 813 that receives an identifier from the infrared node 820, an ID storage unit 812 that stores a preset identifier of the name tag sensor itself, and an identifier of the infrared node 820 that is received by the infrared communication unit 813. The wireless communication unit 811 transmits its own identifier to the wireless network 800.

  When the name tag sensor 810 approaches the infrared node 820, the infrared communication unit 813 receives the identifier from the infrared node 820, and indicates to the wireless base station 80 its own identifier, the identifier of the infrared node 820, and the approach to the infrared node 820. By transmitting the event type, it is possible to notify that the name tag sensor 810 has approached the vicinity of the infrared node 820 which is a fixed node. Conversely, when the name tag sensor 810 leaves the infrared node 820 that started the infrared communication and cannot acquire the identifier of the infrared node 820, the name tag sensor 810 leaves the wireless base station 80 with its own identifier, the identifier of the infrared node 820, and the infrared node 820. By transmitting the event type indicating that the name tag sensor 810 has been disconnected, it is possible to notify that the name tag sensor 810 has left the vicinity of the infrared node 820 that is a fixed node. Note that the wireless communication unit 821 of the infrared node 820 can communicate with the sensor information conversion device 7 and the display PC 5 when setting the identifier of the infrared node 820.

<Communication procedure between storage device and camera PC>
FIG. 3 shows a communication procedure when the storage device 4 requests one image from the camera PC 210.

  The storage device 4 transmits an image request message with the IP address of the storage device 4 as the transmission source and the IP address of the camera PC 210 as the transmission destination (S1).

  When relaying the image request message, the request conversion device 3 on the communication path of the image request message changes the destination of the image request message to the IP address of the transmission control device 20, and further changes the IP address of the transmission source. The request conversion device 3 is changed to transfer the image request message to the transmission control device 20 (S2). At this time, the request conversion apparatus 3 refers to the address conversion table 30 shown in FIG. 4 to convert the IP address of the original destination camera PC 210 and the port number of the transmission control apparatus 20 in association with each other. The transmission control device 20 can identify the camera PC 210 that is the original transmission destination.

  FIG. 4 is an explanatory diagram illustrating an example of the address conversion table 30 set in advance in the request conversion apparatus 3. The address conversion table 30 includes, in one entry, a transmission source IP 301 that stores the IP address of the storage device 4, a transmission destination IP 302 that stores the IP address of the camera PC 210 that is the final destination of the image request message, and a transmission destination. Destination port 303 for storing the port number, transfer destination IP 304 for storing the IP address of the transmission control device 20 as a destination in place of the IP address of the camera PC 210 (destination IP 302), and the transfer destination port of the transmission control device 20 And a transfer destination port 305 for storing the number.

  Here, in the address conversion table 30 of the present invention, the value of the transfer destination port 305 is set from the IP address of the transmission destination IP 302. That is, part or all of the IP address of the destination camera PC 210 may be the port number of the transfer destination port 305. Thereby, the transmission control apparatus 20 that receives the image request message can easily identify the destination camera PC 210 by referring to the port number. If a one-to-one correspondence can be taken between an IP address and a port number, a part of the IP address does not necessarily have to be a port number.

  If the same entry as the source IP address / destination IP address / destination port of the message sent from the storage device 4 side exists in the address conversion table 30, the request conversion device 3 sends the message source Is changed to the IP address of the request conversion apparatus 3, the transmission destination is changed to the contents of the transfer destination IP 304 of the entry, and the transfer is performed after the transmission destination port is changed to the contents of the transfer destination port 305 of the entry.

  Further, when the transmission destination address from the transmission control device 20 side is the request conversion device 3 and there is an entry whose transmission source IP address / transmission source port is equal to the transmission destination address and the transmission destination port, respectively, the transmission source of the message The message is transferred after the IP address and port are changed to the contents of the destination IP / port of the entry.

In the example of FIG. 4, the IP address of the storage device 4 is 10.0.0.2, the IP address of the transmission control device 20 of the camera group 2-0 is 10.0.2.20, and the transmission of the camera group 2-1 The case where the IP address of the control device 20 is 10.0.2.21 is shown.
When the storage device 4 transmits an image request message of 10.0.1.10 as the IP address of the destination camera PC 210, the request conversion device 3 refers to the address conversion table 30 and sets the destination IP address to the camera group 2- The image request message in which the IP address of the transmission control device 20 is changed to 10.0.2.20 of the transfer destination IP 304 and the destination port is changed to 10110 of the transfer destination port 305 is transferred to the transmission control device 20. .

  Next, in S3 of FIG. 3, the transmission control device 20 that has received the image request message transferred from the request conversion device 3 refers to the transfer destination table 230 shown in FIG. The camera PC 210 is determined and an image request message is transmitted to the camera PC 210.

  Here, the transfer destination table 230 shown in FIG. 5 is set in advance in the transmission control apparatus 20, and includes a reception port 2301 that stores the port number received by the transmission control apparatus 20 in one entry, and an image request message. A transfer destination URL 2302 for storing a destination to which the URL is transferred.

  The transmission control device 20 checks the transmission destination port of the image request message received from the request conversion device 3, searches the transfer destination table 230, and obtains the address (URL) of the camera PC 210 to be transferred. Here, the URL represents the access method to the camera PC 210. For example, if “http://camera1.example.com:80/getimage”, the destination address is camera1. example. com, the transmission destination port is 80, the transmission protocol is HTTP, and the request is a character string “/ getimage”.

  Next, in FIG. 3, the camera PC 210 transmits a reply message including the image from the camera 220 to the transmission control device 20 (S4). This reply message includes a high-definition image and information indicating the priority for transferring the high-definition image. The information indicating the priority is set by the camera PC 210 and is the value of the priority field included in the packet of the reply message. The transmission control device 20 rewrites the fields related to these priorities to thereby store the storage device 4. Controls the frame rate of moving images stored in the. The information indicating the priority may be stored as a service type value if the protocol of the network 100 is IPv4, and as a Class value if the protocol is IPv6.

  The transmission control device 20 receives the reply message from the camera PC 210 and includes the high-definition image according to the priority information included in the reply message and the information (sensor information) from the sensor information conversion device 7 and the display PC 5. Determine the priority of sending a reply message.

  If the transmission priority is lower than a certain threshold, the transmission control device 20 does not send back a message (image) of the camera PC 210 of the IP address, and makes an image acquisition request again to the camera PC 210 (S5). The transmission control device 20 and the camera PC 210 repeat the above steps S4 and S5, and the transmission control device 20 follows the priority after the priority of the camera PC 210 exceeds a predetermined threshold or is repeated up to a certain upper limit number of times. After the waiting time is inserted, a reply message in which the priority camera ID and priority information are added to the reply message is returned to the request conversion apparatus 3 (S6). Note that the waiting time provided by the transmission control device 20 is set to be larger as the priority becomes lower, for example.

  Here, the priority for each camera PC 210 managed by the transmission control apparatus 20 is stored in the priority history table 240 shown in FIG. The priority history table 240 shown in FIG. 6 is set in advance in the transmission control device 20, and stores the camera ID 2401 for storing the identifier of the camera PC 210 in one entry and the latest priority of the image of the camera PC 210. The latest priority 2402 to be stored, the average priority 2403 for storing the average value of the priority of the image, and the sensor information 2404 for storing the information received from the sensor information conversion device 7 and the display PC 5 are included.

  The sensor information 2404 stores detection information (priority camera ID) from the sensor information conversion device 7 and a priority instruction of the camera PC 210 from the display PC 5. For example, in FIG. 6, sensor information 2404 of the entry of camera ID 2401 = Camera 3 stores information “disp” as information indicating that there is an instruction to increase the priority from the display PC 5.

  In FIG. 6, “Nameid1” and “Nameid2” are stored in the sensor information 2404 of the entry of camera ID 2401 = Camera2 as identifiers of the name tag sensor 810 from the sensor information conversion device 7. It shows that the name tag sensor 810 having passed the vicinity of the infrared node 820. As described above, when the sensor information 2404 includes any value, the transmission control device 20 transmits the information of the corresponding camera ID with the highest priority.

  Next, in FIG. 3, the request conversion device 3 that has received the reply message from the transmission control device 20 refers to the address conversion table 30 shown in FIG. 4 and converts the source address of the received reply message to the camera PC 210. After the destination address is converted into the storage device 4, the reply message is transferred to the storage device 4 (S7).

  In this way, the storage device 4 recognizes that a high-definition image has been returned from the camera PC 210 and stores the image in the storage device 4.

<Processing in transmission control device>
FIG. 7 shows an example of processing performed in the transmission control device 20, and is a flowchart of processing executed when an image request message is received from the request conversion device 3.

  First, when receiving an image request message from the request conversion device 3, the transmission control device 20 searches the transfer destination table 230 using the reception port as a key to determine the transfer destination camera PC 210 as described above, and transfers the image request. (S11).

  Then, the transmission control device 20 receives the reply message from the camera PC 210, and extracts the priority of the image included in the header of the reply message and the ID of the camera 220 or the camera PC 210 (S12). The priority of the image is substituted for the variable Pnow.

  Next, the transmission control device 20 searches the priority history table 240 using the ID of the camera PC 210 as a key (S13). If sensor information is present in the retrieved entry, the image of this camera PC 210 is treated as the highest priority, so transfer processing is performed without inserting a delay (S14, S24, S20).

  In the transfer process of step S20, priority information and sensor information are added to the header of the reply message and transmitted to the request conversion device 3. At this time, in the IP network between the transmission control device 20 and the request conversion device 3, the IP priority between the transmission control device 20 and the request conversion device 3 is written by writing the priority of the image not only in the reply message but also as the priority information of the packet of the IP layer which is the lower layer It can also be used for level priority control.

  On the other hand, if it is determined in step S14 that there is no sensor information in the retrieved entry, normal transmission priority determination processing is performed in step S15 and subsequent steps. In step S15, it is determined whether or not the priority of the image included in the reply message is zero. As a result of the determination, if the priority of the image included in the reply message is 0, the process proceeds to step S21. If not, the process proceeds to step S16.

  In step S21, since the priority of the image is 0, it is determined that the priority of the image is very low, and an image request is made to the transfer destination camera PC 210 again. At this time, in order to prevent the reply to the storage device 4 from being interrupted due to the repetition of the image request for a long period, the repetition process is performed only when the number of repetitions is less than a predetermined upper limit of 10 ( S23, S11) When the number of repetitions reaches 10, the above transfer process is performed after the priority is minimized (S22, S20). When the image request is repeated to the camera PC 210, a predetermined delay (for example, 200 msec) is inserted in step S23.

On the other hand, if it is determined in step S15 that the priority of the image is a positive value, the process proceeds to step S16 and the current image priority Pnow extracted in step S12 is stored in the priority history table 240. A value obtained by subtracting the average priority 2403 is calculated as the latest priority 2402. If the latest priority is P'now and the average priority is Pave,
P'now = Pnow-Pave
It becomes. With this process, the priority of the image of the camera PC 210 once set to a high priority is gradually lowered with the passage of time if there is no instruction from the sensor information or the display PC 5.

Next, in step 17, the transmission control device 20 updates the values of the average priority and the latest priority in the priority history table 240. Here, a new average priority 2403 is obtained by taking a weighted average between the average of the priorities up to the previous time and the latest priority of the image. That is, if the new average priority is P'ave,
P′ave = (99 × Pave + Pnow) ÷ 100
It becomes. The transmission control apparatus 20 stores the new average priority P′ave in the average priority 2403 of the entry of the camera ID 2401 currently focused on, and stores the latest priority Pnow obtained in step S16 in the latest priority 2402. .

  In step S18, the latest priority 2402 obtained in step S16 is compared with the latest priorities 2402 of other camera IDs in the priority history table 240, and the priority of the camera ID currently focused on is compared. Find the degree ranking. Next, in step S19, when the transmission priority of the camera PC 210 enters the top three, the process proceeds to the transfer process without inserting a delay. On the other hand, if it is lower than the top four, each time the priority of transmission of the camera PC 210 drops from the previous value, a predetermined delay (for example, 20 ms) is inserted and the process proceeds to the transfer process in step S20 ( That is, delay time [ms] = (rank-3) * 20).

  With the above processing, when the ID of the name tag sensor 810 and the display instruction from the display PC 5 are set in the sensor information 2404 of the priority history table 240, the image (high definition image) received from the camera PC 210 is displayed. Although it is transferred to the request conversion apparatus 3 as it is, since the delay increases as the priority decreases, the frame rate of the image of the camera PC 210 decreases.

  That is, the storage device 4 of the present embodiment acquires a high-definition image frame by frame when requesting an image to one camera PC 210, so that the next image is returned after the high-definition image is returned. If the delay is increased, it takes time to acquire one image, and the frequency of image requests to the camera PC 210 stored in the storage device 4 decreases. As a result, the frame rate of the image from the camera PC 210 stored in the storage device 4 decreases.

  Also, the priority of the image of the camera 220 that constantly transmits a high priority is evaluated by evaluating the transmission priority based on the difference between the average of the priorities of the images of the camera 220 and the latest priority. Can be lowered relatively.

  Next, FIG. 8 is a flowchart when the transmission control device 20 receives sensor information from the sensor information conversion device 7. When receiving the sensor information from the sensor information conversion device 7, the transmission control device 20 extracts the camera ID, the name tag ID, and the event type from the received sensor information (S31).

  Next, in step S32, it is determined whether the name tag sensor 810 has approached the infrared node 820 or the detected name tag sensor 810 has left the infrared node 820 for the event type extracted by the transmission control device 20 in step S31. In the case of approach, the process proceeds to step S33, and in the case of separation, the process proceeds to step S34.

  If the event type determination is access information indicating that the name tag sensor 810 has approached the infrared node 820, the transmission control device 20 searches the priority history table 240 from the camera ID extracted from the sensor information in step S33. The ID of the name tag sensor 810 is added to the sensor information 2404 of the entry corresponding to the camera ID.

  On the other hand, if it is determined in step S32 that the event type extracted from the sensor information is departure information, in step S34, the transmission control device 20 searches the priority history table 240 from the camera ID and corresponds to the camera ID. The ID of the name tag sensor 810 is deleted from the sensor information 2404 of the entry. As a result, once the ID of the name tag sensor 810 is registered in the sensor information 2404 and the priority of the camera ID is increased, the ID of the name tag sensor 810 is deleted from the sensor information 2404 when the name tag sensor 810 is removed. The degree is reduced, and it is possible to prevent the state where the priority is kept high forever.

  The priority change request from the display PC 5 sets dummy person approach information to the camera 220 for the camera PC 210 whose priority is to be increased, and leaves the camera for the camera PC 210 whose priority is to be decreased. This can be dealt with by the display PC 5 sending a message to the transmission control device 20 as information of the above.

<Details of message>
FIG. 9 is an example of an image request message issued by the storage device 4. As a message complying with HTTP, it is expressed as an instruction to acquire (GET) information of a path “/ getimage”. Upon receiving this image request message, the camera PC 210 transmits an image of one frame to the transmission control device 20.

  FIG. 10 is an example of a reply message to the image request issued by the camera PC 210. In the figure, “X-ICN-Precedence: 20” on the 8th line indicates the priority of the image, “X-ICN-Camera-Id: 15” on the 9th line indicates the camera ID of the camera PC 210, and 11th line. The high-definition image data is shown after “JFIF” in the eye. FIG. 10 shows the data part of the reply message, and the header part including the destination address, destination port, source address, and source port is omitted.

  FIG. 11 is an example of a format of a sensor information message transmitted by the sensor information conversion apparatus 7. In the present embodiment, among the formats in the figure, the event type, name tag ID, and camera ID are used. As described above, the approach or departure from the name tag sensor 810 is stored in the event type, the identifier of the name tag sensor 810 communicated with the infrared node 820 by infrared rays is stored in the name tag ID, and the name tag sensor 810 detects the sensor ID. The identifier of the camera PC 210 corresponding to the infrared node 820 notified to the information conversion device 7 is stored.

<Processing of request conversion device>
FIG. 12 is a flowchart illustrating an example of processing executed when the request conversion device 3 receives a message from the storage device 4 or the transmission control device 20.

  When receiving a message from the storage device 4 or the transmission control device 20, the request conversion device 3 extracts the transmission source address, transmission destination address, transmission source port, and transmission destination port of the received message (S41).

  Then, the request conversion apparatus 3 searches for an entry in which the extracted transmission source address, transmission destination address, and transmission destination port match the transmission source IP 301, transmission destination IP 302, and transmission destination port 303 of the address conversion table 30 ( S42). In step S43, if the entry exists as a result of the search in step S42, the process proceeds to step S44, and if the entry does not exist, the process proceeds to step S45.

  In step S44 when there is an entry, it is determined that the message is an image request message from the storage device 4 to the camera PC 210, and in order to transfer the message to the transmission control device 20, the message destination address, destination The port is changed to the contents of the transfer destination IP 304 and the transfer destination port 305 in the searched entry, and the message source address is converted to the IP address of the request conversion device 3 and transferred (S44, S45, S46). , S47).

  On the other hand, if it is determined in step S43 that there is no entry, it is determined whether the destination address of the message is the request conversion device 3 (S48). As a result of the determination, if the message is not addressed to the request conversion device 3, this message is not transferred and is transferred as it is (S49, S47).

  When the destination of the message is the request conversion device 3, the process proceeds to step S50, and an entry in which the transmission source address and the transmission source port of the received message match the transfer destination IP 304 and the transfer destination port 305 in the address conversion table 30 is displayed. Search for. In step S51, the request conversion apparatus 3 determines whether or not there is an entry. If there is no entry, the process proceeds to steps S49 and S47. To do.

  On the other hand, if an entry exists, the process proceeds to step S52. In step S52, since this message is high-definition image information sent from the camera PC 210 to the storage device 4, in order to transfer the message to the storage device 4, the message source address, the source port, and the destination The address is changed and transferred to the contents of the transmission destination IP 302, transmission destination port 303, and transmission source IP 301 in the entry searched in the address conversion table 30 (S52, S53, S54, S47).

  As a result of the above processing, the image request message transmitted from the storage device 4 to the camera PC 210 has its destination address changed to the transmission control device 20, the destination port changed to the port number corresponding to the address of the camera PC 210, and the source address. Is changed to the IP address of the request conversion device 3, a reply message is always sent to the request conversion device 3 in response to an image request from the storage device 4.

  Then, the reply message to the image request message addressed to the request conversion device 3 from the transmission control device 20 converts the transmission source address and port in the request conversion device 3 into the address and port number of the camera PC 210 requested by the storage device 4. As a result, the storage device 4 can perform processing as if it were directly communicating with the camera PC 210.

  Therefore, when the present invention is applied to an existing network video monitoring system, it is only necessary to insert the request conversion device 3 and the transmission control device 20 of the present invention between the camera PC 210 and the storage device 4, and to install a number of cameras 220. The moving image can be accumulated at a frame rate corresponding to the priority of the image. By suppressing the frame rate according to the priority, even a network video monitoring system including a large number of cameras 220 can suppress an excessive network load.

  In the above embodiment, an example is shown in which the camera 220 that captures an image and the camera PC 210 that transfers the image captured by the camera 220 to the monitoring center 1 side are provided independently. You may replace with the camera apparatus which transmits to 1 side. In particular, in a network video monitoring system or video network system whose main purpose is to store images captured by a camera device in the storage device 4, it is not necessary for the camera device to have a thumbnail generation function or a feature amount extraction function. The apparatus only needs to include a transmission unit that transmits one frame at a time to the monitoring center 1 side (transmission control apparatus 20) in response to the image request message.

  In the above embodiment, an example is shown in which the camera device (camera 220 and camera PC 210) transmits an image frame by frame in response to an image request. However, a predetermined number of frames (images) are transmitted. Also good.

<Summary>
As described above, in the present invention, by performing frame rate control (bandwidth control) based on the priority of the reply message from the camera PC 210, video monitoring can be performed with the minimum necessary bandwidth, and a large number of cameras 220 can be monitored. Even in a system provided with the network, it is possible to suppress an excessive load on the network.

  Further, in the present invention, when performing bandwidth control, the cameras do not exchange information, and the communication bandwidth can be adjusted based on information from a plurality of cameras 220 (camera PCs 210). Therefore, even if a system using a communication line (or network) with a narrow communication band is used, stable image transfer is possible.

  In addition, a new method for setting priorities can be introduced without changing the camera 220 or the camera PC 210, so that it is possible to quickly respond to the advancement of image analysis methods and the appearance of new sensor devices. It becomes.

  Furthermore, since the priority can be changed according to the sensor information or the instruction from the display PC 5, the image that the monitor is trying to capture can be distributed with a high priority, so that the efficiency of monitoring can be improved. .

  Bandwidth control based on content level information (sensor information and designation from the display PC 5) can be performed without changing existing devices (camera 220, camera PC 210, and storage device 4). It is possible to minimize the cost for introducing the control function.

  As described above, the present invention can be applied to a network video monitoring system that includes a large number of cameras and transfers images.

It is a block diagram which shows an example of the network image | video monitoring system to which this invention is applied. It is a block diagram which shows the outline | summary of the communication between the components of the network video monitoring system shown in FIG. It is a sequence diagram which shows the communication procedure when a storage device requests | requires one image with respect to camera PC. It is explanatory drawing which shows an example of the address conversion table of a request conversion apparatus. It is explanatory drawing which shows an example of the transfer destination table of a transmission control apparatus. It is explanatory drawing which shows an example of the priority log | history table of a transmission control apparatus. 5 is a flowchart showing an example of processing performed in the transmission control device, and shows processing executed when an image request message is received from the request conversion device 3; It is a flowchart which shows an example of a process when a transmission control apparatus receives sensor information from a sensor information converter. It is explanatory drawing which shows an example of the message of the image request which a storage device issues It is explanatory drawing which shows an example of the reply message with respect to the image request which camera PC issues. It is explanatory drawing which shows an example of the format of the message of the sensor information which a sensor information converter transmits. It is a flowchart which shows an example of the process performed when a request conversion apparatus receives a message from a storage device or a transmission control apparatus. It is a block diagram which shows the structure of a name tag sensor and an infrared node.

Explanation of symbols

1 Monitoring Center 3 Request Conversion Device 4 Storage Device 5 Display PC
6 Search PC
7 Sensor information conversion device 8 Sensor network 20 Transmission control device 30 Address conversion table 210 Camera PC
220 Camera 230 Destination table 240 Priority history table 810 Name tag sensor 820 Infrared node

Claims (15)

A plurality of camera devices for taking images;
A storage device for storing images taken by the camera device;
A network connecting the camera device and the storage device, wherein the storage device transmits an image request to the camera device, and upon receiving the image request, the camera device transmits an image as a reply message to the storage device. In the video network system,
Installed between the network and the storage device, receives the image request sent from the storage device to the camera device, converts the address and port included in the image request, and then sends the image request to the camera device side. A request conversion device that receives the reply message sent to the storage device by the camera device, converts the address and port included in the reply message, and then forwards the reply message to the storage device;
The image request is installed between the network and the camera device, receives the image request transferred by the request conversion device, identifies the camera device to which the image request is transferred from the information of the port included in the image request, and Is transferred to the specified camera device, a reply message transmitted by the camera device in response to the image request is received, an address and a port included in the reply message are converted, and then transferred to the request conversion device. A transmission control device,
A video network system characterized by comprising: The request conversion device includes:
When an image request is received from the storage device, the destination address included in the image request is converted to the address of the transmission control device instead of the address of the camera device set by the storage device, and the address of the camera device is converted. Set the corresponding value in the destination port, convert the source address of the image request to the address of the request conversion device instead of the storage device, and then transfer the image request to the transmission control device,
When a reply message is received from the transmission control device, a destination address included in the reply message is converted into an address of the storage device, and a destination port value included in the reply message is converted into a corresponding source address. And then transfer the reply message to the storage device,
The transmission control device includes:
From the destination port included in the image request received from the request conversion device, identify the camera device that transfers the image request, and transfer the image request to the identified camera device,
A reply message transmitted by the camera device in response to the image request is received, a destination address included in the reply message is converted into an address of the request conversion device, and a source address included in the reply message is corresponded The video network system according to claim 1, wherein a value is set as a destination port and then transferred to the request conversion device. Upon receiving the image request, the camera device transmits a predetermined number of images as a reply message,
The transmission control device includes:
Based on the information of the camera device to be prioritized received from another computer, the priority of the reply message to be transferred to the request conversion device is set for each camera device, and the reply message received based on the priority is forwarded. The video network system according to claim 1, wherein the timing to perform is changed.   The other computer is a first computer that designates an identifier of a camera device that sets a higher priority of a reply message to the transmission control device and transmits the information as information on the camera device to be prioritized. The video network system according to claim 3. The other computer is connected to a sensor network including a fixed node and a mobile node, receives an event from the mobile node that has detected the fixed node from the sensor network, and identifies a camera device corresponding to the fixed node from the event A sensor information conversion device,
4. The video network system according to claim 3, wherein the sensor information conversion apparatus notifies the transmission control apparatus to set a high priority for a reply message of the identified camera device. 5. The mobile node acquires an identifier of the fixed node when communicating with the fixed node, and transmits an event including the identifier of the fixed node and the identifier of the mobile node to the sensor information conversion device,
The sensor information conversion device identifies a camera device from an identifier of a fixed node included in the event, and notifies the transmission control device of the identifier of the camera device and the identifier of the mobile node. 5. The video network system according to 5. The other computer is
Connected to a sensor network including a fixed node and a mobile node, receives an event from the mobile node that has detected the fixed node from the sensor network, identifies a camera device corresponding to the fixed node from the event, and identifies the identified camera A sensor information conversion device for notifying the transmission control device to set the priority of the reply message of the device high;
When receiving the notification from the sensor information conversion device, a first computer that requests an image of the specified camera device from the storage device;
The video network system according to claim 3, further comprising: The transmission control device includes:
The video according to claim 3, wherein priority is accumulated for each camera device, and the priority is changed based on the accumulated priority value and the latest priority value for each camera device. Network system. The transmission control device includes:
4. The video network system according to claim 3, wherein a timing for transferring the received reply message is changed by setting a delay time based on the priority. A transmission control device connected to a plurality of camera devices for capturing images, transferring an image request received from a network to the camera device, and transferring a reply message including an image transmitted by the camera device to the network. ,
The transmission control device includes:
Identify the camera device that forwards the image request from the destination port included in the image request received from the network, forward the image request to the identified camera device,
When the reply message corresponding to the image request is transferred to the network, a value corresponding to the source address of the reply message is set in the destination port, and the address of the transmission control device is set as the source address. Forward the reply message from
Timing for setting the priority of the reply message to be transferred to the network for each camera apparatus based on the information of the camera apparatus to be prioritized received from another computer and transferring the reply message received based on the priority A transmission control device characterized by changing   The other computer is a first computer that designates an identifier of a camera device that sets a higher priority of a reply message to the transmission control device and transmits the information as information on the camera device to be prioritized. The transmission control device according to claim 10. The other computer is connected to a sensor network including a fixed node and a mobile node, receives an event from the mobile node that has detected the fixed node from the sensor network, and identifies a camera device corresponding to the fixed node from the event A sensor information conversion device,
11. The transmission control apparatus according to claim 10, wherein the sensor information conversion apparatus notifies the transmission control apparatus to set a higher priority for a reply message of the identified camera device. The mobile node acquires an identifier of the fixed node when communicating with the fixed node, and transmits an event including the identifier of the fixed node and the identifier of the mobile node to the sensor information conversion device,
The sensor information conversion device identifies a camera device from an identifier of a fixed node included in the event, and notifies the transmission control device of the identifier of the camera device and the identifier of the mobile node. 12. The transmission control device according to 12. The transmission control device includes:
The transmission according to claim 10, wherein priority is accumulated for each camera device, and the priority is changed based on the accumulated priority value and the latest priority value for each camera device. Control device. The transmission control device includes:
The transmission control apparatus according to claim 10, wherein a timing for transferring the received reply message is changed by setting a delay time based on the priority.