JP2001016570A - Video information acquisition device and video distributor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To distribute a video image acquired from a different resource without notifying an acquisition destination by distributing a real time video image that attains a stable video distribution service. SOLUTION: A command interpretation section 114 receives a distribution request command from a client through a communication control section 140, interprets it, a request issue section 112 sends a video information request to a request reception section 122 in response to the result of interpretation, a resource discrimination section 124 designates a video resource (video file 132, camera 136, and video resource of other device) on the basis of a resource file 128 in response to the request, control sections 130, 134 acquire video information from the video resource and send it to a video information input section 126, the input section 126 sends video information to a video information transmission section 116, and the transmission section 116 distributes video information to the client. When the video resource is located in another device, a request transmission section 138 sends the request to the other device, receives the video information from the other device and sends it to the video information input section 126.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network system and, more particularly, to a video information acquisition device and a video distribution device for acquiring a video taken by a camera in response to a request from a client and distributing the obtained video. About.

[0002]

2. Description of the Related Art Conventionally, real-time video distribution via a network has been performed by using a security system or a so-called VOD (Video On Demand).
Like OnDemand) systems, dedicated networks, terminals, software, etc. have been used. However, with the improvement of the performance of the Internet and personal computers and their spread to the general public and the spread of the World Wide Web (WWW),
As with browsing WW documents, there have been demands for viewing real-time video in a normal hardware and software environment, and for fitting real-time video as part of a WWW document. As a technology to respond to this,
The -42279 consists of a command interpreter that interprets the tag indicating the image information described in the WWW document as a camera control command, and a camera controller that controls the camera based on the command interpretation result and obtains video information and video information. A camera server has been proposed.

[0003]

SUMMARY OF THE INVENTION The above prior arts include:
There are the following problems. In other words, in the method of directly acquiring the video by interpreting the result of interpreting the distribution request command from the client to the camera control unit, the camera server itself always exchanges data with the client, so that a user who can view the video is required. Is limited by the number of clients that can simultaneously access the camera server.
When providing services over the Internet, Internet users around the world are potential users, except for special sites with membership. As can be seen from the fact that many famous sites have mirror sites, if access is concentrated, a single server can handle the problem regardless of how much the server's processing capacity or line thickness is increased. is not.
In particular, in the case of real-time video, it is expected that access will be concentrated several times more than that of a normal server depending on the contents of a program due to the very characteristic of real-time performance. At the same time, the time of day when important events are occurring and the time when others can only see ordinary images,
It is also conceivable that the number of accesses fluctuates extremely. Therefore, there is a need for a scalable system that can provide a stable service regardless of the number of accesses. Further, in the configuration including the command interpretation unit and the camera control unit, the video can be obtained only from the camera controlled by the camera control unit. Therefore, for example, if a failure occurs in a connected camera, the camera server can no longer deliver video. The user who had been watching the video had to access it again if another server distributed the video instead.

[0004] It is an object of the present invention to provide a real-time video distribution apparatus capable of flexibly coping with a change in the number of accessing clients and providing a stable video distribution service. Another object of the present invention is to provide a video distribution apparatus that can distribute a video obtained from different types of resources using the same interface and does not make the user aware of the video source. is there. Still another object of the present invention is to provide a video distribution apparatus capable of promptly switching resources and continuing video distribution when a failure occurs in video acquisition or the like.

[0005]

In order to achieve the above object, the present invention relates to a video information acquisition device, a request receiving unit for receiving a video information request, and a resource storage unit for storing setting information relating to a video resource to be used. (Setting information storage means), a resource determination means for determining a video resource for obtaining video information based on the setting information of the resource storage means, a video information obtaining means for obtaining video information from the determined video resource, Video information returning means for returning the obtained video information to the issuer of the information request is provided. Further, when the video resource determined by the resource determination unit is an imaging device connected to the video information acquisition device, the video information acquisition unit controls the imaging device to acquire video information. . If the video resource determined by the resource determination unit is a video resource connected to another video information acquisition device different from the video information acquisition device that has received the video information request, the video information acquisition device The video information acquisition unit transmits a video information request to the other video information acquisition device, and receives the video information acquired from the video resource in the other video information acquisition device from the other video information acquisition device. I am trying to do it. When the video resource determined by the resource determination unit is image data stored in a storage unit connected to the video information acquisition device, the video information acquisition unit controls the storage unit to store the image data. It reads out and generates and acquires video information. The image processing apparatus further includes a plurality of video resources and a timer device, wherein the resource storage unit stores setting information relating to the plurality of video resources to be switched, and each time the time measured by the timer elapses, the video is stored based on the setting information. A means for switching a video resource used for acquiring information is provided. If it is not possible to obtain a video from the video resource determined by the resource determining unit, the setting information on the video resource in the resource storage unit is changed, and the video information obtaining unit is specified by the changed setting information. Video acquisition is performed using the video resources obtained. Further, a storage device is provided, and means for storing video information similar to the video information returned to the request source of the video information in the storage device is provided.

A video distribution device for distributing video via a network, comprising: any one of the video information acquisition devices described above; and video distribution means for distributing the video acquired by the video information acquisition device. Video distribution means, a distribution request receiving means for receiving a video distribution request from a client, a request issuing means for issuing a video information request to the request receiving means based on the received video distribution request, and the video information A video information transmitting unit that distributes the video information passed from the video information returning unit of the acquisition device to the client is provided. The request issuing means generates a request for video information for one frame. The request issuing unit may issue a video information request to the video acquisition unit if the connection with the client that has requested the distribution is not completed at the time when the video information distribution unit has finished transmitting the video to the client. I try to repeat. Further, the request issuing unit issues one video information request to the resource determining unit when the distribution request receiving unit simultaneously receives a video distribution request from a plurality of clients, and the video information distribution unit transmits the request to the resource determining unit. Are distributed to the plurality of clients.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a video distribution server to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a video distribution server to which the present invention has been applied. In FIG. 1, reference numeral 100 denotes a video distribution server;
Video distribution unit 110, video acquisition unit 120, communication control unit 14
0. The video distribution unit 110 receives a distribution request command from a client via the communication control unit 140, interprets the received distribution request command, and issues a video information request to the video acquisition unit 120 according to the interpretation result. Issuing unit 112,
An image information transmitting unit 116 is provided that sends back the image acquired by the image acquiring unit to the client. In this embodiment, the video distribution unit 110 has a function as a WWW server, and interprets a CGI command for a real-time video described in a WWW document requested to be distributed by a client as a distribution request command from the client. Shall be. Of course, there is another method of receiving a distribution request command, and for example, a method of reading a tag for displaying an image file as a command for real-time video distribution is also possible as in Japanese Patent Application Laid-Open No. 10-42279. .

[0008] The video acquisition unit 120 includes a request reception unit 122 that receives a video information request, and a resource determination unit 12 that determines a video resource from which video information is actually acquired.
4. It has a video information input unit 126 that sends back video information obtained from the video resource in the requested form to the request source. The resource file 128 stores setting information on video resources used by the server. In the present embodiment, as an image resource, it is possible to read from the image file 132, capture an image captured by the camera 136 connected to the server, and use an external server connected via the communication control unit 140. The image acquisition unit 120 includes a file control unit 130, a unit that acquires image information from each image resource.
The camera includes a camera control unit 134 and a request transmission unit 138.

FIG. 2 shows an example of information on video resources stored in the resource file 128. In the present embodiment, the video distribution server 100 can use a plurality of video resources, and one of them is designated as a resource used for acquiring a video to be actually distributed. In FIG. 2, a used resource 202 indicates a resource used for acquiring a video to be distributed among available resources. The resource number 204 is a number for identifying each available resource. The resource type 206 indicates the type of each resource, and in this embodiment, one of a camera, an external server, and a file is set. The attribute information 208 is information necessary for accessing each resource and acquiring video information. The attribute 208 differs depending on the resource type 206. For example, when the resource is a camera, an input / output terminal for controlling the camera, when the resource is a file, a stored directory name, and when the resource is an external server, an address on a network is used. No.

There is other information that can be stored in the resource file 128 and used when acquiring video information. For example, even if it is called video information, there are various data formats, screen sizes, color palettes, and the like. In this embodiment, these video format instructions are embedded in a command for requesting video distribution, and a video information request is generated accordingly. However, the video information request is written in a resource file as setting information. For example, a distribution request command and a video information request can be simplified, and the screen size and the like can be flexibly changed according to the situation.

FIG. 3 is a flowchart showing a processing procedure of video distribution in the video distribution server, and FIG. 4 is a flowchart showing a processing procedure of video information acquisition. FIGS. 5, 6, and 7 are diagrams each showing a data flow from acquisition of video information from a video resource to distribution. 5, 6, and 7, reference numeral 510 denotes a client that receives video distribution, and reference numeral 500 denotes a network that connects the video distribution server 100 and the client 510.

Based on the flowcharts of FIGS. 3 and 4,
A procedure in which the video distribution server 100 distributes a video will be described. First, the video distribution server 100 sends the client 510
When the command distribution unit 114 receives a video distribution request from the server (step 302), the command interpreting unit 114 interprets the content (step 30).
4), the request issuing unit 112 generates a video information request according to the result (step 306). It should be noted that the video distribution server 100 has a plurality of clients 510.
When a video distribution request is received from, the request issuing unit 112 generates one video information request and issues the request to the video acquisition unit 120.
As described above, in the present embodiment, the video data format, screen size, and the like are specified in the distribution request, and the video information request is generated accordingly. The acquired video information is processed into a designated form and distributed to the client. In this embodiment, when a distribution request is received, the distribution of the video information is continued until the connection with the client is completed. At that time, the video information request generates one frame, and the obtained video information is distributed to the client one frame at a time. This allows the client to continuously view the latest video. In this embodiment, it is assumed that the connection is disconnected, but it may be determined that the connection is terminated by receiving an explicit distribution termination request. The request issuing unit 112 sends the generated video information request for one frame to the video acquisition unit 1
20 (step 308), the video acquisition unit 120 that has received this sends a video acquisition process (step 31).
0).

In the video acquisition process 310, when the request receiving unit 120 receives a video information request (step 402), the resource discriminating unit 124 checks the setting of a resource used for acquiring a video (step 404). In this embodiment, the used resource 2 is
The resource number 206 is checked, and the resource type 206 and the attribute information 208 of the resource having the corresponding resource number 204 are read. Set resource 202
If the resource type 206 is camera (step 40)
6), the resource determination unit 124 instructs the camera control unit 134 to acquire video information, and the camera control unit 134
6 is taken in as the data by taking in the video shot at that time (step 408). The camera used may be a digital camera that can be controlled from a computer, or a home analog video camera connected to a video capture board. In the case of a digital camera, the angle, focus, exposure, and the like of the camera can be controlled and adjusted from a server depending on the functions provided by the camera. An analog camera is sufficient for simply capturing an image. In this case, a video capture board plays a role of an image capturing device, and performs a process of capturing an image input as an NTSC signal or the like as digital data. The acquired video information is processed by the video information input unit 126 into a requested video format such as a screen size (step 416),
Send back to the issuer of the video information request (step 41
8). FIG. 5 shows the flow of commands and video information when the camera is used as a video resource. This flow is indicated by broken lines and arrows.

When the resource type 206 of the set resource 202 is an external server (step 41)
0), the resource determining unit 124 determines whether the
, The request transmitting unit 138 transmits a video information request to the video obtaining unit of the server set in the attribute information 208 (step 41).
2). The video distribution server that has become a video resource similarly acquires video information from a camera or the like connected to itself by the video information acquisition processing 310, and returns the video information to the video distribution server that transmitted the request. FIG. 6 shows the flow of commands and video information when an external server is used as a video resource. Here, the first video distribution server that has received the video distribution request from the client is identified as A, and the second video distribution server as a video resource is identified as B. As described above, in the video distribution server to which the present invention is applied, since the video distribution unit and the video acquisition unit are separated,
Video acquisition units can be connected in multiple stages. Thereby,
A server that receives a distribution request from a client and a server that obtains video information are separately provided, and a plurality of video distribution servers can distribute the video of one camera. This can be achieved, for example, by distributing the load by adjusting the number of distribution request receiving servers (corresponding to server A in FIG. 6) in accordance with the scale of the client, or when another failure occurs in the camera connected to the own device. A stable distribution service such as a backup function for switching to a server camera and continuing video distribution can be realized. Here, when switching to a camera of another server and continuing the video distribution when a camera connected to the own device fails, when the failure of the camera is detected, the operator manually or instructs the resource according to a program instruction. Change the resource number of the resource used in the file.

If the resource type 206 of the set resource 202 is neither a camera nor an external server,
It is determined that the file is read from the file, the resource determination unit 124 instructs the file control unit 130 to acquire video information, and the file control unit 130 controls the storage device 132 to read the video file that has been shot and stored in advance. (Step 414). FIG. 7 shows the flow of commands and video information when a video file stored in advance is used as a video resource. When a video file that has been shot and stored in advance is used as a video resource, real-time video shot at that time cannot be distributed. However, alternative video at the time of failure or rebroadcasting of video once distributed can be performed in the same manner as real-time video distribution without changing the interface.

When the video obtained by the video obtaining unit 120 is passed to the video distribution unit 110, the video information transmitting unit 116 distributes the video to the client (step 312). As described above, when the video distribution server 100 receives a video distribution request from a plurality of clients 510 and the request issuing unit 112 issues one video information request, the video distribution unit 110 When the image information acquired by the unit 120 is passed, the image information transmitting unit 116 transmits the image information to each client 510 that has issued the image distribution request.
Deliver to. Here, the connection of the client is confirmed (step 314). If the connection is broken, the distribution process is terminated as it is. If the connection is continued, the process returns to step 308, and the request issuing unit 112 acquires the video information request to acquire the video. Department to obtain and distribute video information. In this way, by successively distributing the video of each frame, the client can see the latest video that changes every moment.

[0017] Continuous video distribution by this method depends on factors such as machine performance and network congestion on the distribution path, so that performance at the full motion video level cannot be guaranteed. However, many systems do not always require a full-motion video, and a pseudo video can sufficiently achieve the purpose. For example, it can be applied to monitoring of plant and traffic conditions, education and training while communicating with remote places, distribution of live video of events, and the like. Further, in moving image distribution using a streaming technology or the like, a server having a dedicated function and display software on a client side corresponding to the server are required. However, in the present invention, since a pseudo moving image is realized by continuously transmitting still images of one frame at a time,
Users can watch dynamic real-time video with general WWW browsing software.

In the case where a continuous video is distributed, even if the distribution side transmits the video at a fixed interval, the arrival may be delayed depending on the above-mentioned network congestion, or the processing may catch up due to the low processing performance of the client. Since such a situation occurs, it is necessary to perform processing such as appropriately thinning out and displaying frames on the client side. However, according to the present invention, the delivery of the next frame is performed after the delivery of the video for one frame is completed, so that the video is naturally thinned out according to the display status on the client, and no special processing is performed. Even so, the user can always see the latest video.

Next, a case where a plurality of cameras are connected to the video distribution server and a camera for acquiring a video is automatically switched at regular intervals will be described with reference to FIGS. 8, 9 and 10. FIG. FIG. 8 is a block diagram illustrating a configuration of a video distribution server to which a plurality of cameras are connected. In FIG. 8, a second camera 806 and a camera control unit 804 for controlling the second camera 806
And a timer 802 used for resource switching is provided.

FIG. 9 shows a resource file 128 in this embodiment. In FIG. 9, reference numeral 902 denotes a resource number used for acquiring a video to be distributed. Reference numeral 904 denotes an order in which the resources are switched, and in this drawing, the camera having the resource number 1 and the camera having the resource number 2 are alternately switched.
In the present embodiment, the time for switching the resources is assumed to be predetermined. For example, not only the order as the information of the switching order, but also information about the time interval is retained, and the resources are switched according to the information. Is also good. Further, in the present embodiment, it is assumed that the delivered video information is stored as a file on the disk 132, and the video information stored as a substitute video is delivered when a failure occurs in the camera. Here, when distributing video information stored as a substitute video when a camera failure occurs, as described above, when a camera failure is detected, the operator manually or program Change the resource number of the resource used in the resource file according to the instruction. Reference numeral 906 denotes a setting as to whether or not to save the file to the disk.
08 is a storage directory for saving. 91
0, 912, and 914 are identification numbers, resource types, and attribute information of each available resource.

FIG. 10 is a flowchart showing a processing procedure in which the video acquisition unit 120 switches video resources at regular intervals by a timer. The process of switching the video resources in the video distribution server of FIG. 8 will be described with reference to the flowchart of FIG. When an event requesting the image acquisition unit 120 to perform processing occurs (step 10).
02), the request receiving unit 122 checks the contents of the event. If the event is a video information request (step 1004), the resource determining unit 124 looks at the resource file 128 and, if the used resource 902 is a camera (step 1005), checks whether the corresponding camera is available (step 1006). If the camera is operating, the video information acquisition processing (step 310) is performed as it is. If a failure has occurred in the camera, the resource number 3 is set to the used resource 902 and the video resource is switched to a file (step 310). Step 1008). In addition, since the video read out from the file and distributed is stored again as it is, the file save 906 is stored in the OF file.
It is set to F (step 1010). If the camera is operating normally and the video resource is other than the camera, the process proceeds to the next step without performing anything, and video information is acquired by the video information acquisition processing 310. After the image information acquisition processing 310 is completed and the acquired image information is sent to the issuer of the image information request, if the file save 906 is ON (step 1012), that is, if the image is acquired from the camera, the same image The information is stored as a file in a predetermined directory (step 1014).
If the event that occurred in the determination of step 1004 is not a video information request reception, but the event that occurred is a call from a timer indicating that the resource switching time has come (step 1016), the resource switching order 904 Is checked, the video resource is changed to the next camera (step 1018), and the timer is set again (step 1020). If the event is neither a video information request nor a timer, nothing is done.
When all the processes are completed in this way, the video acquisition unit 120 enters the event waiting again.

As described above, according to the present invention, the switching of the video resources can be easily performed, and the configuration can be flexibly changed according to the situation. Switching of video resources can be considered for use in a monitoring system equipped with a plurality of cameras, event relaying, or prompt switching to a backup system when a failure occurs.

[0023]

As described above, according to the present invention, it is possible to disperse the load of a server for access from a client by connecting video distribution servers in multiple stages, and to achieve a scalable configuration according to the scale of the client. Can be easily changed, so that a stable video distribution service can be provided. Further, according to the present invention, it is possible to distribute a video acquired from different types of resources such as a camera, an external server, and a file without making the user aware of the difference between the video resources, and a flexible configuration can be achieved. Become. Further, according to the present invention, it is possible to easily change the video resource, so that even when a failure occurs, the video resource can be quickly switched to the spare video resource and the video distribution can be continued to the user. further,
By switching video resources with timer processing,
A monitoring system or the like that automatically switches a plurality of cameras can be realized. Further according to the invention,
By repeating the cycle of issuing the video information request for one frame, acquiring and distributing the video information until the connection with the client ends, continuous real-time video distribution becomes possible. According to the present invention, continuous video distribution is enabled only by the mechanism on the server, and the user does not need to prepare software corresponding to a special data format or the like. You can enjoy the video.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a video distribution server to which the present invention has been applied.

FIG. 2 is a data configuration diagram illustrating an example of a video resource file used in a video distribution server.

FIG. 3 is a diagram illustrating a flowchart of a video distribution process.

FIG. 4 is a diagram illustrating a flowchart of a process of acquiring video information.

FIG. 5 is a diagram showing a data flow in the case of distributing video information acquired from a camera connected to a server.

FIG. 6 is a diagram showing a data flow when a server which has received a distribution request from a client acquires video information from another server and distributes the video information.

FIG. 7 is a diagram showing a data flow when distributing video information stored in a storage device connected to a server.

FIG. 8 is a block diagram showing another configuration of the video distribution server to which the present invention has been applied.

FIG. 9 is a data configuration diagram showing another example of a video resource file.

FIG. 10 is a diagram illustrating a flowchart of processing for switching video resources by a timer.

[Explanation of symbols]

 Reference Signs List 100 video distribution server 110 video distribution unit 112 request issuing unit 114 command interpretation unit 116 video information transmission unit 120 video acquisition unit 122 request reception unit 124 resource discrimination unit 126 video information input unit 128 resource file 130 file control unit 132 video file 134 804 Camera control unit 136, 806 Camera 138 Request transmission unit 140 Communication control unit 500 Network 510 Client 802 Timer

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Claims (11)

[Claims] 1. A request receiving unit for receiving a video information request, a resource storage unit (setting information storage unit) for storing setting information relating to a video resource to be used, and obtaining video information based on the setting information of the resource storage unit. Resource determining means for determining a video resource; video information obtaining means for obtaining video information from the determined video resource; and video information returning means for returning the obtained video information to the issuer of the video information request. Video information acquisition device. 2. The video information acquisition device according to claim 1, wherein, when the video resource determined by the resource determination device is a photography device connected to the video information acquisition device, the video information acquisition device performs the photography. A video information acquisition device, wherein the video information is acquired by controlling the device. 3. The video information acquisition device according to claim 1, wherein the video resource determined by the resource determination unit is:
In the case where the video resource is a video resource connected to another video information acquisition device different from the video information acquisition device that has received the video information request, the video information acquisition unit of the video information acquisition device performs the acquisition of the other video information. A video information acquisition device, wherein a video information request is transmitted to the device, and the video information acquisition device receives the video information acquired from the video resource from the other video information acquisition device. 4. The video information acquisition device according to claim 1, wherein the video resource is determined when the video resource determined by the resource determination unit is image data stored in a storage unit connected to the video information acquisition device. A video information obtaining apparatus, wherein an information obtaining unit controls the storage unit to read out image data to generate and obtain video information. 5. The video information acquisition device according to claim 1, further comprising a plurality of video resources and a timer device, wherein said resource storage means stores setting information relating to a plurality of video resources to be switched, and A video information acquisition apparatus, comprising: means for switching a video resource used for acquiring video information based on the setting information every time the measured time elapses. 6. The video information acquisition device according to claim 1, wherein when it is impossible to acquire a video from the video resource determined by the resource determination unit, setting information on the video resource in the resource storage unit is changed, The video information obtaining apparatus, wherein the video information obtaining means obtains a video using a video resource specified by the changed setting information. 7. The video information acquisition apparatus according to claim 1, further comprising a storage device, and a unit configured to store the same video information as the video information returned to the request source of the video information in the storage device. Video information acquisition device. 8. A video distribution apparatus for distributing video via a network, comprising: the video information acquisition apparatus according to claim 1; and a video acquired by the video information acquisition apparatus. Video distribution means for distributing the video information, the video distribution means receiving a video distribution request from a client, and video request information to the request receiving means based on the received video distribution request. A video distribution device, comprising: a request issuing unit that issues a request; and a video information transmitting unit that distributes video information passed from a video information returning unit of the video information acquisition device to a client. 9. The video distribution apparatus according to claim 8, wherein the request issuing unit generates a request for video information for one frame. 10. The video distribution device according to claim 8, wherein the request issuing unit has not terminated the connection with the client that has requested the distribution at the time when the video information distribution unit has finished transmitting the video to the client. In a case, the image distribution apparatus repeatedly issues a video information request to the video acquisition unit. 11. The video distribution device according to claim 8, wherein the request issuing unit transmits one video information to the resource determining unit when the distribution request receiving unit receives a video distribution request from a plurality of clients simultaneously. A video distribution device which issues a request, and wherein the video information distribution means distributes video information returned in response to the request to the plurality of clients.