JP4351084B2 - Image communication system, image distribution server, image communication method, and program - Google Patents

Description

  The present invention relates to an image communication technique, and more particularly to an image communication system in which a plurality of client terminals exchange images via an image distribution server.

In recent years, with the spread of packet communication networks represented by the Internet and the development of data communication technology that uses them, image communication systems and services that exchange not only voice and still images but also moving images, that is, images, are provided. Has been.
A typical video communication system is a video conference system. This is a system in which a plurality of client terminals arranged at each point and one image distribution server are connected via the Internet, and voice and images are exchanged between the client terminals via the image distribution server (for example, (See Non-Patent Document 1, etc.).

  In such an image communication system, since the amount of image data to be distributed is large, the image format and communication environment in which display processing can be performed differ for each client terminal. For example, the image format that can be displayed on the client terminal depends on the size and resolution of the display screen of the client terminal. In addition, the communication speed of the line through which the client terminal accesses the Internet varies greatly depending on whether the line is ADSL or optical fiber.

  Therefore, in order to distribute an appropriate image to each client terminal, conventionally, parameters relating to the distribution image from each client terminal to the image distribution server in advance, such as the frame rate of the received video, the quality of the received video, the size of the received video, and the communication A value such as a network speed is notified, and an image is distributed from the image distribution server in an image format based on these parameters.

The applicant has not yet found prior art documents related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in this specification.
MeetingPlaza network meeting room service, http://www.meetingplaza.com/index-j.html, NTT IT Corporation

However, in such a conventional technique, since the individual client terminals notify the image distribution server of the image format and the communication network speed that are desired to be received in advance, the above-mentioned notification notified from the individual client terminals. Even if the image is distributed from the image distribution server based on the parameters, depending on the processing performance and operation status of the client terminal, the processing load on the received image will increase significantly, and normally required steady processing or different applications There was a problem that other processes such as were stagnant.
The present invention is for solving such a problem, and an image communication system, an image distribution server, a client terminal, an image communication method, and an image communication system capable of displaying a received image without stagnation of other processing in individual client terminals, and The purpose is to provide a program.

In order to achieve such an object, an image communication system according to the present invention is connected to a plurality of client terminals that transmit and receive images via a communication network and display received images via the communication network. An image communication system comprising an image distribution server that converts an image transmitted from each client terminal into an image quality corresponding to the performance of each client terminal and distributes the image quality, wherein the client terminal is a static performance of its own device. An environment information management unit for notifying the image distribution server via the communication network, and an operation information management unit for notifying the image distribution server of the operation information indicating the dynamic performance of the own device via the communication network. provided, the image distribution server, the ring shown notified from the client terminal, the static performance of the client terminal Information, operation information indicating the dynamic performance of the client terminal, the number of connections of the client terminal that distributes the image from the image distribution server, and the connection of the client terminal that requests connection to the image distribution server An image distribution control unit that determines the image quality of an image to be distributed to the client terminal based on the number of standbys, and an image processing unit that converts the image quality of the image to be distributed to the client terminal based on the image quality is there.

The image distribution server according to the present invention is connected to a plurality of client terminals that transmit and receive images and display received images via a communication network, and transmits images transmitted from the respective client terminals to individual client terminals. An image distribution server that converts image quality according to performance and distributes the image quality information, which is notified from the client terminal via the communication network and indicates the static performance of the client terminal, and the operation of the client terminal The client based on the operation information indicating the performance, the number of connections of the client terminal that distributes the image from the image distribution server, and the connection waiting number of the client terminal that requests connection to the image distribution server An image distribution control unit that determines the image quality of an image to be distributed to the terminal, and an image distribution control unit based on the image quality. Those comprising an image processing unit for converting the image quality of an image to be distributed to the client terminal.

  At this time, as environment information, information including at least one of CPU capability, OS type, memory type, and image drawing API indicating the performance of the client terminal computer is used. As an example, information including at least one of the CPU usage rate, the memory usage status, and the communication network usage status indicating the performance of the client terminal computer may be used.

  The image distribution control unit may determine at least one of the image size, the frame rate, and the image compression rate as the image quality.

  Further, when the image distribution control unit determines the image quality, the image quality is determined based on the number of image distribution destination client terminals connected via the communication network in addition to the environment information and the operation information. Also good.

In addition, the image communication method according to the present invention includes a plurality of client terminals that transmit and receive images via a communication network and display received images, and images transmitted from each client terminal connected via the communication network. Is an image communication method used in an image communication system including an image distribution server that converts image quality into image quality according to the performance of each client terminal and distributes the image quality, and includes environment information indicating the static performance of the client terminal. A step of notifying the image distribution server from the client terminal via the communication network, a step of notifying operation information indicating the dynamic performance of the client terminal from the client terminal to the image distribution server via the communication network, and , reported from the client terminal, the client Environment information indicating the static performance of the terminal, operation information indicating the dynamic performance of the client terminal, the number of connections of the client terminal that distributes images from the image distribution server, and connection to the image distribution server. Determining the image quality of an image to be distributed to the client terminal based on the requesting waiting number of connections of the client terminal, and an image distribution server to determine the image quality of the image to be distributed to the client terminal based on the image quality The step of converting.

In addition, the program according to the present invention is connected to a plurality of client terminals that transmit and receive images and display received images via a communication network, and the images transmitted from each client terminal are converted into the performance of each client terminal. Environment information indicating the static performance of the client terminal notified from the client terminal via the communication network to the computer of the image distribution server that converts the image quality to the corresponding image quality and delivers the dynamic performance of the client terminal To the client terminal based on the operation information indicating the number of connections, the number of connections of the client terminal that distributes the image from the image distribution server, and the number of standby connections of the client terminal that requests connection to the image distribution server Determining the image quality of the image to be distributed, and based on the image quality It is intended to execute the steps of converting the image quality of an image to be distributed to client terminals.

According to the present invention, the environment information indicating the static performance of the client terminal, the operation information indicating the dynamic performance of the client terminal, and the image from the image distribution server notified from the client terminal by the image distribution server. Since the image quality of the image to be distributed to the client terminal is determined based on the number of connections of the client terminal that distributes the image and the connection waiting number of the client terminal that is requesting connection to the image distribution server, Images can be distributed with image quality suitable for the processing performance and operation status of each client terminal. Therefore, the received image can be displayed without stagnation of other processes at each client terminal, and a stable image distribution service can be provided.

Next, embodiments of the present invention will be described with reference to the drawings.
[Image communication system]
First, an image communication system according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of an image communication system according to an embodiment of the present invention.
This image communication system includes an image distribution server 1, one or more client terminals 2 (2A, 2B, 2C) and an IP network such as the Internet or an intranet, and connects the image distribution server 1 and the client terminal 2. The communication network 10 is configured.

  In the present embodiment, the image distribution server 1 converts the images 3A, 3B, and 3C transmitted from each client terminal 2 into images 4A, 4B, and 4C having image quality according to the performance of each client terminal 2. When each of the client terminals 2 is distributed, the environment information 5A, 5B, 5C indicating the static performance of the client terminal 2 and the operation information 6A, 6B, 6C indicating the dynamic performance are distributed via the communication network 10 from each client terminal 2. Images 4A, 4B, 4C delivered to the client terminal 2 based on the environment information 5A, 5B, 5C and the operation information 6A, 6B, 6C notified from the client terminal 2 by the image delivery server 1 The image quality of each of the images 4A, 4B, and 4C to be distributed to the client terminal 2 is converted based on the image quality. In which it was to be delivered.

In the present invention, the static processing performance determined by the physical configuration of the computer of the client terminal 2 is expressed as the static performance of the client terminal 2, and for example, fixed that does not change due to an increase or decrease in processing load on the computer. Performance.
The dynamic processing performance determined by the operation state of the computer of the client terminal 2 is expressed as the dynamic performance of the client terminal 2 and refers to the fluid performance that changes depending on the increase or decrease in processing load on the computer.

[Image distribution server]
Next, the configuration of the image distribution server 1 will be described in detail with reference to FIG. FIG. 2 is a functional block diagram showing a functional configuration of the image distribution server 1.
The image distribution server 1 is a server device realized by a computer, and has a control unit, a storage unit, and a communication unit as main physical configurations (not shown). The control unit includes a microprocessor such as a CPU and its peripheral circuits, and implements various functional units by reading and executing a predetermined program. The storage unit includes a storage device such as a hard disk or a memory, and stores various information used for processing in the control unit and a program read into the control unit. The communication unit is a circuit unit that transmits and receives various types of information via the communication network 10.

Functional units realized by the control unit include an image distribution control unit 11, an image processing unit 13, an environment information management unit 14, and an operation information management unit 15.
The image distribution control unit 11 is a functional unit that controls the entire image distribution process in the image distribution server 1. The image processing unit 13 is a functional unit that processes an image exchanged with the client terminal 2. The image processing unit 13 A receives an image from the client terminal 2, and an image transmission unit transmits the image to the client terminal 2. 13B and an image codec unit 13C that performs image conversion processing.

The environment information management unit 14 is a functional unit that manages environment information of the client terminal 2 connected via the communication network 10.
The operation information management unit 15 is a functional unit that manages operation information of the client terminal 2 connected via the communication network 10.

A table management unit 16 is provided in the storage unit. In the table management unit 16, various information used for processing in the image distribution control unit 11 is managed as a table. As this table, there are a distribution image quality threshold value table 16A, an environment information table 16B, a connected client number management table 16C, and a client information management table 16D.
A communication interface unit 12 is provided in the communication unit. The communication interface unit 12 realizes data communication between the image distribution control unit 11 and the client terminal 2 connected via the communication network 10.

[Client terminal]
Next, the configuration of the client terminal 2 will be described in detail with reference to FIG. FIG. 3 is an explanatory diagram showing a functional configuration of the client terminal 2.
The client terminal 2 is a terminal device realized by a computer, and has a control unit, a storage unit, and a communication unit as a main physical configuration (not shown). The control unit includes a microprocessor such as a CPU and its peripheral circuits, and implements various functional units by reading and executing a predetermined program. The storage unit includes a storage device such as a hard disk or a memory, and stores various information used for processing in the control unit and a program read into the control unit. The communication unit is a circuit unit that transmits and receives various types of information via the communication network 10.

The functional units realized by the control unit include a client terminal control unit 21, an image management unit 23, an environment information management unit 24, and an operation information management unit 25.
The client terminal control unit 21 is a functional unit that controls various processes including image communication at the client terminal 2.
The image management unit 23 includes an image input unit 23A that captures an image to be transmitted from the camera 20A connected to the client terminal 2 to the image distribution server 1, and a display that is connected to the client terminal 2 and receives an image received from the image distribution server 1. This is a functional unit having an image output unit 23B that outputs to 20B and an image codec unit 23C that performs image processing on images from the camera 20A and images on the display 20B.

  The environment information management unit 24 is a functional unit that manages environment information of the client terminal 2. The environment information management unit 24 includes, as specific function means, an environment information operation input unit 24A that accepts environment information of the client terminal 2 input by the user, and configuration information of the client terminal 2 based on the configuration information. An environment information automatic acquisition unit 24B that automatically acquires environment information related to the client terminal 2 and an environment information test program unit 24C that executes a predetermined test program to automatically acquire environment information related to the client terminal 2 are provided.

The operation information management unit 25 is a functional unit that manages the operation information of the client terminal 2.
The operation information management unit 25 includes, as specific function means, an operation information automatic acquisition unit 25A that automatically acquires operation information related to the client terminal 2 based on the configuration information of the client terminal 2, and a predetermined test program. An operation information test program unit 25B is provided that executes and automatically acquires operation information related to the client terminal 2.

Various information used for processing in the client terminal control unit 21 is managed as a table in the storage unit. These tables include an environment information storage table 24D used by the environment information management unit 24, an operation information storage table 25C used by the operation information management unit 25, and an operation information threshold value table 25D.
A communication interface unit 22 is provided in the communication unit. The communication interface unit 22 realizes data communication between the client terminal control unit 21 and the image distribution server 1 connected via the communication network 10.

[table]
Next, configuration examples of various tables used in the image distribution server 1 and the client terminal 2 will be described with reference to FIGS.
FIG. 4 is a configuration example of a distribution image quality threshold table 16A used in the image distribution server 1. The distribution image quality threshold table 16A is a table for determining an image quality appropriate for the client terminal 2, and is provided for each environment information of the client terminal 2, here, the CPU capability. In each table, the image quality used for distribution is associated with each combination of the operation information, that is, the CPU usage rate and the number of images to be distributed (number of client terminals).

FIG. 5 is a configuration example of the environment information table 16 </ b> B used in the image distribution server 1. This environment information table 16B is a table for determining the environment information of the client terminal 2, and the CPU capability, test value (number of CPU clocks) of the client terminal 2, vendor ID, CPU family, CPU model, and CPU stepping. Are associated with each other.
FIG. 6 is a configuration example of the connected client number management table 16 </ b> C used in the image distribution server 1. This connected client number management table 16C manages the number of client terminals 2 participating in the video conference.

FIG. 7 is a configuration example of the client information management table 16D used in the image distribution server 1. The client information management table 16D is a table for managing environment information and operation information of each client terminal 2 participating in the video conference.
FIG. 8 is a configuration example of the environment information recording table 24D used in the client terminal 2. This environment information recording table 24D is a table for managing the environment information of the client terminal 2, and the environment of the client terminal 2, such as CPU capability value, test value, vendor ID, CPU family, CPU model, CPU stepping, etc. Information is recorded.

  FIG. 9 is a configuration example of the operation information recording table 25C used in the client terminal 2. The operation information recording table 25C is a table for managing the operation information of the client terminal 2, and operation information such as the CPU usage rate at the client terminal 2 and the previous measurement CPU usage rate is recorded.

[First Embodiment]
Next, the operation of the image communication system according to the first embodiment of the present invention will be described with reference to FIG. FIG. 10 is a sequence diagram showing an operation of the image communication system according to the first embodiment of the present invention.
In the present embodiment, a case where the first client terminal 2A participates in a video conference started by the image distribution server 1 as illustrated in FIG. 11 will be described by taking a video conference as an example. FIG. 11 is a configuration example of the image communication system according to the first embodiment of the present invention.

The configurations of the image distribution server 1 and the client terminal 2 are the same as those in FIGS. 2 and 3 described above.
Further, the CPU capability (P-II, P-III, etc.) used in the computer of the client terminal 2 is used as environment information, and the CPU usage rate (10%, 25%, etc.) is used as operation information. As the quality, an image size (VGA, CIF, QCIF, SQCIF, etc.) and a frame rate (15 fps, 5 fps, etc .: Frame Per Second) are used.
Further, as a premise, the CPU of the client terminal 2A is “P-II / 300 MHz”, and the environment information recording table 24D of the client terminal 2A has “P-II” as the value of the CPU capability as shown in FIG. It shall be recorded.

Note that VGA (Video Graphics Array) is a standard for video cards for image processing used in personal computers, and CIF (Common Intermediate Format) is a video compression coding standard H.264 of ITU. This is an image format common to the world defined by H.261. Further, QCIF (Quarter CIF) is a quarter size format in which the vertical and horizontal sizes of CIF are halved, and SQCIF (Sub QCIF) is a format having a size almost ½ of QCIF. The resolution (number of dots) of VGA, CIF, QCIF, and SQCIF is 640 × 480, 352 × 288, 176 × 144, and 128 × 96, respectively.
Of “P-II / 300 MHz” indicating the CPU, “P-II” indicates a CPU type such as Pentium (registered trademark), for example, and “300 MHz” indicates its operating frequency.

First, the image distribution control unit 11 of the image distribution server 1 starts a video conference in which the client terminal 2A can participate in response to a request for starting a video conference by an operator operation or the arrival of a reserved video conference start time. A state is set (step 100).
Similarly, the client terminal control unit 21 of the client terminal 2A also requests the video distribution server 1 to participate in a video conference in response to the start request of the video conference by the user or the arrival of the reserved video conference start time. (Step 101).

In response to the video conference participation request from the client terminal 2A, the image distribution control unit 11 of the image distribution server 1 changes the connection waiting number from “0” to “0” in the connection client number management table 16C as shown in FIG. The number of clients requesting connection is managed (step 102). Then, a report request for environmental information is made to the client terminal 2A (step 103).
In response to the environmental information report request from the image distribution server 1, the client terminal 2A acquires the CPU capability value “P-II” of the environmental information recording table 24D from the environmental information management unit 24 as environmental information (step 104). This is reported to the image distribution server 1 (step 105).

In response to the environmental information report from the client terminal 2A, the image distribution control unit 11 of the image distribution server 1 compares the environmental information value “P-II” with the environmental information table 16B as shown in FIG. Step 106), the CPU capability of the client terminal 2A is determined as "P-II" (Step 107). Then, it is recorded in the client information management table 16D that the CPU capability of the client terminal 2A is “P-II” (step 108).
Next, the image distribution control unit 11 of the image distribution server 1 requests image transmission to the client terminal 2A (step 109).

In response to the image transmission request from the image distribution server 1, the client terminal control unit 21 of the client terminal 2A takes in the video shot by the camera 20A from the image input unit 23A and encodes it by the image codec unit 23C (step 110). Then, transmission to the image distribution server 1 is started (step 111).
In response to the start of image transmission from the client terminal 2A, the image distribution control unit 11 of the image distribution server 1 makes a transmission request for operation information to the client terminal 2A (step 112).

The client terminal control unit 21 of the client terminal 2A acquires the operation information by the operation information automatic acquisition unit 25A or the operation information test program unit 25B in response to the operation information transmission request from the image distribution server 1 (step 113). As shown in FIG. 15, the acquired operation information “25%” is recorded in the operation information recording table 25C (step 114), and the operation information “25%” is reported to the image distribution server 1 (step 115).
In response to the operation information report from the client terminal 2A, the image distribution control unit 11 of the image distribution server 1 records the operation information “25%” in the client information management table 16D as shown in FIG. 16 (step 116). ).

Next, the image distribution control unit 11 of the image distribution server 1 refers to the connected client number management table 16C, the client information management table 16D, and the distribution image quality threshold table 16A, and the quality of the image distributed to the client terminal 2A. Is determined (step 117).
In this case, as shown in FIG. 17, since the CPU capability of the client terminal 2A is “P-II” in the client information management table 16D, the distribution image quality threshold table 16A for P-II is selected. From the set of the number of images “1” determined by the sum of the number of connections and the number of connections waiting in the connected client number management table 16C and the CPU usage rate “25%” of the client terminal 2A in the client information management table 16D. The quality of the image distributed to the client terminal 2A is determined to be “QCIF / 5fps” with reference to the distribution image quality threshold table 16A for P-II.

Next, the image distribution control unit 11 of the image distribution server 1 once decodes the encoded image received from the client terminal 2A by the image codec unit 13C (step 118), and then distributes the image to the client terminal 2A. Is encoded again into the quality “QCIF / 5fps” (step 119) and distributed to the client terminal 2A (step 120). Also, as shown in FIG. 18, in the connected client number management table 16C, the number of connections is set to “1” and the number of waiting connections is set to “0” (step 121), and the processing at the time of a series of video conference participation is completed.
The client terminal control unit 21 of the client terminal 2A decodes the image distributed from the image distribution server 1 by the image codec unit 23C, outputs the image from the image output unit 23B to the display 20B (step 122), and participates in a series of video conferences. End the hour process.

As described above, the environment information indicating the static performance of the client terminal 2 and the operation information indicating the dynamic performance are notified from the client terminal 2 to the image distribution server 1 via the communication network 10. The image quality of the image distributed to the client terminal 2 is determined based on the environment information and the operation information notified from the terminal 2, and the image quality of the image distributed to the client terminal 2 is converted based on the image quality and distributed. When the client terminal 2 participates in the video conference, the image distribution server 1 adjusts the quality of the image distributed to the client terminal 2 and distributes an image according to the processing capability of the client terminal 2 can do.
Therefore, each client terminal 2 can display a received image without stagnation of other processes, and can provide a stable image distribution service.

In the above description, the case where the CPU capability (P-II, P-III, P-IV, etc.) used in the computer of the client terminal 2 is used as environment information has been described as an example. Even if an OS type (Windows 98, Windows XP, etc .: trademark registration), a memory type (500 MB, 1 GB, etc.), or an API (Application Program Interface) type of image drawing (DirectX8, DirectX9, etc .: trademark registration) is used. These may be combined.
Further, although the usage rate of the CPU used in the computer of the client terminal 2 is used as the operation information, the usage status of the memory used in the computer of the client terminal 2 or the usage status of the communication network 10 may be used. These may be combined.

Further, as the image quality, the image size (VGA, CIF, QCIF, SQCIF, etc.) and the frame rate (15 fps, 5 fps, etc.) are used, but the image compression rate (compression rate 1/5, compression rate 1/15, Compression ratio 1/30, etc.) may be used, or these may be combined.
Moreover, although the case where the client terminal 2A reports the environment information and the operation information based on the request from the image distribution server 1 has been described as an example, the client terminal 2 may autonomously report to the image distribution server 1. Good.

[Second Embodiment]
Next, the operation of the image communication system according to the second embodiment of the present invention will be described with reference to FIGS. 19 and 20 are sequence diagrams illustrating the operation of the image communication system according to the second embodiment of the present invention.
In the first embodiment described above, the case where one client terminal 2A participates in a video conference started by the image distribution server 1 as illustrated in FIG. 11 has been described as an example. In the present embodiment, as shown in FIG. 21, a case where one client terminal 2A is already participating in the video conference and a second client terminal 2B is participating in the video conference is taken as an example. explain. FIG. 21 is a configuration example of an image communication system according to the second embodiment of the present invention.

The configurations of the image distribution server 1 and the client terminal 2 are the same as those in FIGS. 2 and 3 described above.
Further, the CPU capability (P-II, P-III, etc.) used in the computer of the client terminal 2 is used as environment information, and the CPU usage rate (10%, 25%, etc.) is used as operation information. The image size (VGA, CIF, QCIF, SQCIF, etc.) and the frame rate (15 fps, 5 fps, etc.) are used as the quality.
As a premise, the CPU of the client terminal 2A that has already participated in the video conference among the client terminals 2 is “P-II / 300 MHz”, and the CPU of the client terminal 2B that newly participates in the video conference is “P- The environment information recording table 24D of these client terminals 2A and 2B includes “P-II” and “P-III” as the CPU capability values as shown in FIGS. Is recorded.

Further, in the operation information recording table 25C of the client terminal 2A, as shown in FIG. 23, the CPU usage rate value is “25%”, and the previous measurement CPU usage rate value is not recorded. It shall be. Similarly, in the operation information recording table 25C of the client terminal 2B, as shown in FIG. 24, the CPU usage rate value and the previous measurement CPU usage rate value are not recorded.
Also, in the connected client number management table 16C of the image distribution server 1, as shown in FIG. 25, the number of connections is “1” and the number of connection waiting is “0”.

  As an initial state, the image distribution server 1 has started a video conference (step 200), and the client terminal 2A has transmitted an image to the image distribution server 1 via the communication network 10 (step 201). 10, the image is distributed to the client terminal 2A with the image quality of “QCIF / 5fps” based on the distribution image quality threshold value table 16A (step 202).

Here, when a request for participation in the video conference is made from the client terminal 2B to the image distribution server 1 via the communication network 10 (step 203), the image distribution control unit 11 of the image distribution server 1 is shown in FIG. As shown, the connection waiting number value in the connected client number management table 16C is changed from “0” to “1” (step 204).
Then, the image distribution control unit 11 of the image distribution server 1 requests the client terminal 2B to report environment information (step 205).

The client terminal control unit 21 of the client terminal 2B obtains the CPU capability value “P-III” from the environment information recording table 24D in response to the environment information report request from the image distribution server 1 (step 206). Report to the image distribution server 1 (step 207).
The image distribution control unit 11 of the image distribution server 1 compares the value “P-III” of the environment information reported from the client terminal 2B with the environment information table 16B (step 208). The CPU capability of the client terminal 2B is determined as “P-III” (step 209). Then, in the client information management table 16D, as shown in FIG. 26, it is recorded that the CPU capability of the client terminal 2B is “P-III” (step 210).

Next, the image distribution control unit 11 of the image distribution server 1 makes a request for image transmission to the client terminal 2B (step 211).
In response to the image transmission request from the image distribution server 1, the client terminal control unit 21 of the client terminal 2B takes in the video shot by the camera 20A from the image input unit 23A and encodes it by the image codec unit 23C (step 212). Then, transmission to the image distribution server 1 is started (step 213).

In response to the start of image transmission from the client terminal 2B, the image distribution control unit 11 of the image distribution server 1 makes a transmission request for operation information to the client terminal 2A and the client terminal 2B (steps 214 and 215).
The client terminal control unit 21 of the client terminal 2A acquires the operation information in response to the operation information transmission request from the image distribution server 1 (step 216), and the CPU usage rate value of the acquired operation information is “30%”. 23, the CPU usage rate in the operation information recording table 25C is updated from “25%” to “30%”, and the previous measurement CPU usage rate is changed from “unrecorded” to “25%” as shown in FIG. (Step 217), the CPU usage rate “30%” is reported to the image distribution server 1 as operation information (step 218).

  On the other hand, the client terminal control unit 21 of the client terminal 2B acquires the operation information in response to the operation information transmission request from the image distribution server 1 (step 219), and the CPU usage rate value of the acquired operation information is “ In the case of “15%”, as shown in FIG. 24, the CPU usage rate in the operation information recording table 25C is updated from “unrecorded” to “15%” and the previously measured CPU usage rate remains “unrecorded”. (Step 220), and the CPU usage rate “15%” is reported to the image distribution server 1 as operation information (step 221).

As shown in FIG. 27, the image distribution control unit 11 of the image distribution server 1 sets “30%” as the CPU usage rate of the client terminal 2A in the client information management table 16D. Is recorded, and “15%” is recorded as the CPU usage rate of the client terminal 2B (step 222).
Then, the image distribution control unit 11 of the image distribution server 1 refers to the connected client number management table 16C, the client information management table 16D, and the distribution image quality threshold table 16A and distributes it to each of the client terminals 2A and 2B. The image quality is determined separately (step 223).

  In this case, for the client terminal 2A, since the CPU capability of the client terminal 2A is “P-II” in the client information management table 16D, the distribution image quality threshold value table 16A for P-II is selected, The number of images “2” determined by the total value of the number of connections “1” in the connection client number management table 16C and the number of connections waiting “1”, and the CPU usage rate “30” of the client terminal 2A in the client information management table 16D From the set of “%”, the quality of the image distributed to the client terminal 2A is determined to be “SQCIF / 10 fps” with reference to the distribution image quality threshold table 16A for P-II.

  For the client terminal 2B, since the CPU capability of the client terminal 2B is “P-III” in the client information management table 16D, the distribution image quality threshold value table 16A for P-III is selected and connected. The number of images “2” determined by the total value of the number of connections “1” in the client number management table 16C and the number of standby connections “1”, and the CPU usage rate “15%” of the client terminal 2B in the client information management table 16D ”And the distribution image quality threshold value table 16A for P-III, the quality of the image distributed to the client terminal 2B is determined as“ CIF / 15 fps ”.

Next, the image distribution control unit 11 of the image distribution server 1 decodes the encoded image received from the client terminal 2A by the image codec unit 13C (step 224).
Then, in order to distribute the image to the client terminal 2A, the decoded image is encoded into “SQCIF / 10 fps” which is the quality of the image to be distributed to the client terminal 2A (step 225) and distributed to the client terminal 2A (step 226). )
Further, in order to distribute the image to the client terminal 2B, the decoded image is encoded into “CIF / 15 fps” which is the quality of the image to be distributed to the client terminal 2B (step 225), and is distributed to the client terminal 2B (step 227). ).

Similarly, the image distribution control unit 11 of the image distribution server 1 decodes the encoded image received from the client terminal 2B by the image codec unit 13C (step 224).
Then, in order to distribute the image to the client terminal 2A, the decoded image is encoded into “SQCIF / 10 fps” which is the quality of the image to be distributed to the client terminal 2A (step 225) and distributed to the client terminal 2A (step 226). )
Further, in order to distribute the image to the client terminal 2B, the decoded image is encoded into “CIF / 15 fps” which is the quality of the image to be distributed to the client terminal 2B (step 225), and is distributed to the client terminal 2B (step 227). ).
Then, as shown in FIG. 28, the image distribution control unit 11 of the image distribution server 1 sets the connection number to “2” and the connection waiting number to “0” in the connection client number management table 16C (step 228). .

In response to this, the client terminal control unit 21 of the client terminal 2A receives the image from the client terminal 2A distributed from the image distribution server 1 with the quality of “SQCIF / 10fps”, and receives the image from the client terminal 2B. Received with the quality of “SQCIF / 10 fps”, these images are decoded by the image codec unit 13C, and output to the display 20B by the image output unit 23B (step 229).
Further, the client terminal control unit 21 of the client terminal 2B receives the image from the client terminal 2A distributed from the image distribution server 1 with the quality of “CIF / 15 fps”, and receives the image from the client terminal 2B as “CIF / The image codec unit 23C decodes these images, and the image output unit 23B outputs them to the display 20B (step 230).

  Thus, in addition to the environment information and operation information of the client terminal 2, the number of images distributed to each client terminal 2, that is, the number of client terminals 2 connected via the communication network 10 is also taken into consideration. Since the image quality of the image to be distributed to each client terminal 2 is determined, even if a new client terminal 2 participates in the video conference and the number of images to be distributed increases, the image distribution server 1 The image according to the processing capability of each client terminal 2 can be distributed by appropriately adjusting the quality of the image distributed to the client terminal 2.

In the above description, the case where the CPU capability (P-II, P-III, P-IV, etc.) used in the computer of the client terminal 2 is used as environment information has been described as an example. OS types (Windows 98, Windows XP, etc.), memory types (500 MB, 1 GB, etc.), image drawing API types (Direct X8, Direct X9, etc.) may be used, or a combination thereof.
Further, although the usage rate of the CPU used in the computer of the client terminal 2 is used as the operation information, the usage status of the memory used in the computer of the client terminal 2 or the usage status of the communication network 10 may be used. These may be combined.

Further, as the image quality, the image size (VGA, CIF, QCIF, SQCIF, etc.) and the frame rate (15 fps, 5 fps, etc.) are used, but the image compression rate (compression rate 1/5, compression rate 1/15, Compression ratio 1/30, etc.) may be used, or these may be combined.
Moreover, although the case where the client terminal 2A reports the environment information and the operation information based on the request from the image distribution server 1 has been described as an example, the client terminal 2 may autonomously report to the image distribution server 1. Good.

[Third Embodiment]
Next, the operation of the image communication system according to the third embodiment of the present invention will be described with reference to FIG. FIG. 29 is a sequence diagram showing operations of the image communication system according to the third embodiment of the present invention.
In the second embodiment described above, the case where two client terminals 2A and 2B participate in a video conference as illustrated in FIG. 21 has been described as an example. In the present embodiment, as shown in FIG. 30, a video conference is taken as an example, and two client terminals 2A and 2B are already participating in the video conference, and a new application other than the video conference is newly established in the client terminal 2A. The case where it starts is demonstrated as an example. FIG. 30 is a configuration example of an image communication system according to the third embodiment of the present invention.

The configurations of the image distribution server 1 and the client terminal 2 are the same as those in FIGS. 2 and 3 described above.
Each of the client terminals 2A and 2B uses an operation information threshold value table 25D having the contents shown in FIG.
Further, the CPU capability (P-II, P-III, etc.) used in the computer of the client terminal 2 is used as environment information, and the CPU usage rate (10%, 25%, etc.) is used as operation information. The image size (VGA, CIF, QCIF, SQCIF, etc.) and the frame rate (15 fps, 5 fps, etc.) are used as the quality of the image.

  As an initial state, the image distribution server 1 starts a video conference (step 300), and the client terminal 2A transmits an image (A) to the image distribution server 1 via the communication network 10 (step 301). The client terminal 2B transmits an image to the image distribution server 1 via the communication network 10 (step 302).

Here, among the client terminals 2, the CPU of the client terminal 2A that has already participated in the video conference is “P-II / 300 MHz”, and the environment information recording table 24D has a CPU capability value of “P-II”. Is recorded. In the operation information recording table 25C of the client terminal 2A, “30%” is recorded as the value of the CPU usage rate, and “25%” is recorded as the value of the previous measurement CPU usage rate.
Further, since the client terminals 2A and 2B participate in the video conference of the image distribution server 1, the number of connections “2” and the number of connections waiting “0” are recorded in the number of connected clients management table 16C. .

  Accordingly, the image distribution control unit 11 of the image distribution server 1 has the client terminal 2A because the CPU capability of the client terminal 2A is “P-II”, the number of images is “2”, and the CPU usage rate is “30%”. On the other hand, the images received from the client terminal 2A and the client terminal 2B are encoded to “SQCIF / 10 fps” based on the distribution image quality threshold value table 16A and transmitted (step 303).

  Among the client terminals 2, the CPU of the client terminal 2B that has already participated in the video conference is “P-III / 600 MHz”, and the environment information recording table 24D has “P-III” as the value of CPU capability. It shall be recorded. In the operation information recording table 25C of the client terminal 2B, “15%” is recorded as the CPU usage rate value, and “unrecorded” is recorded as the previous measurement CPU usage rate value.

  Accordingly, the image distribution control unit 11 of the image distribution server 1 has the client terminal 2B having the CPU capability “P-III”, the number of images “2”, and the CPU usage rate “15%”. On the other hand, the images received from the client terminal 2A and the client terminal 2B are encoded to “CIF / 15 fps” based on the distribution image quality threshold value table 16A and transmitted (step 304).

  In this state, it is assumed that the client terminal 2A activates an application other than the video conference and the CPU usage rate has increased from “30%” to “45%” (step 305). The operation information management unit 25 of the client terminal 2A periodically acquires operation information (step 306), and in response to the change, the CPU usage rate of the operation information recording table 25C is set as shown in FIG. “30%” is updated to “45%”, and the previous measurement CPU usage rate is updated to “30%” (step 307).

  Then, the client terminal control unit 21 of the client terminal 2A compares the value of the motion information recording table 25C with the motion information threshold value table 25D (step 308). At this time, as shown in FIG. 33, the CPU usage rate “45%” is in the state B, the previous measurement CPU usage rate “30%” is in the state A, and the operation state changes from the state A to the state B. Therefore, the CPU usage rate “45%” is reported to the image distribution server 1 as operation information (step 309).

The image distribution control unit 11 of the image distribution server 1 receives the CPU usage rate “45%” as the operation information of the client terminal 2A, and in the client information management table 16D for the client terminal 2A, as shown in FIG. The CPU usage rate is updated from “30%” to “45%” (step 310).
Further, referring to the client information management table 16D, the connected client number management table 16C, and the distribution image quality threshold table 16A, the image quality distributed to the client terminal 2A is changed from “SQCIF / 10 fps” to “SQCIF / 5 fps”. Because of the change (step 311), the image codec unit 13C changes the quality of the image distributed to the client terminal 2A to “SQCIF / 5fps”, encodes it (step 312), and distributes it to the client terminal 2A (step 313). ).

  In response to this, the client terminal control unit 21 of the client terminal 2A receives from the image distribution server 1 an image whose image quality is changed from “SQCIF / 10 fps” to “SQCIF / 5 fps” and the processing of the CPU is reduced. Then, it is decoded by the image codec unit 23C and output to the display by the image output unit (step 314).

  As described above, since the image quality of the image to be distributed to the client terminal 2 is reviewed according to the change in the operation information notified from the client terminal 2, the client terminal 2 participating in the video conference can recognize the terminal itself. Even if the application other than the video conference is started and the CPU usage rate increases, the image distribution server 1 adjusts the quality of the image distributed to the client terminal 2 and the image according to the processing capability of the client terminal 2. Can be delivered.

In the present embodiment, the operation information is periodically acquired by the client terminal 2, the change of the operation state is confirmed each time, and when the operation state changes, the operation information is stored in the image distribution server 1. However, the image distribution server 1 has changed the quality of the image to be distributed to the client terminal 2 in response to this report. You may make it confirm with the delivery server 1. FIG.
That is, the operation information is periodically acquired by the client terminal 2, and the operation information is reported to the image distribution server 1 each time. When the image distribution server 1 receives this report, the operation state of the client terminal 2 is It may be confirmed whether the image has been changed, and if the change has occurred, the quality of the image distributed to the client terminal 2 may be changed.

In the present embodiment, the case where the CPU usage rate of the client terminal 2 increases has been described as an example. However, the present invention can be similarly applied even when the CPU usage rate decreases.
In the present embodiment, the processing load of the CPU at the time of receiving the image of the client terminal 2 is changed by changing the quality of the image distributed from the image distribution server 1 in accordance with the change in the CPU usage rate of the client terminal 2. However, the processing load of the CPU at the time of image transmission of the client terminal 2 is adjusted by changing the quality of the image transmitted from the client terminal 2 to the image distribution server 1. Alternatively, both may be performed.

In the above description, the case where the CPU capability (P-II, P-III, P-IV, etc.) used in the computer of the client terminal 2 is used as environment information has been described as an example. OS types (Windows 98, Windows XP, etc.), memory types (500 MB, 1 GB, etc.), image drawing API types (Direct X8, Direct X9, etc.) may be used, or a combination thereof.
Further, although the usage rate of the CPU used in the computer of the client terminal 2 is used as the operation information, the usage status of the memory used in the computer of the client terminal 2 or the usage status of the communication network 10 may be used. These may be combined.

  Further, as the image quality, the image size (VGA, CIF, QCIF, SQCIF, etc.) and the frame rate (15 fps, 5 fps, etc.) are used, but the image compression rate (compression rate 1/5, compression rate 1/15, Compression ratio 1/30, etc.) may be used, or these may be combined.

[Fourth Embodiment]
Next, with reference to FIGS. 35 and 36, the operation of the image communication system according to the fourth embodiment of the present invention will be described. FIG. 35 is a sequence diagram illustrating an operation information acquisition operation (sequential acquisition) in the client terminal 2 of the image communication system according to the fourth embodiment of the present invention. FIG. 36 is a sequence diagram illustrating an operation information acquisition operation (periodic acquisition) in the client terminal 2 of the image communication system according to the fourth embodiment of the present invention.
In the present embodiment, a specific operation for acquiring operation information in the client terminal 2 will be described.

As shown in FIG. 35, the client terminal 2 acquires the operation information when it receives a request for operation information from the image distribution server 1 (sequential acquisition), and as shown in FIG. 36, the client terminal 2 acquires the operation information. There is one that is periodically performed (periodic acquisition) after the client terminal control unit 21 of No. 2 is activated.
In addition, as a method of acquiring operation information in the client terminal 2, a method of automatically acquiring the CPU usage rate from the registry value that is management information of the OS of the client terminal 2 by the operation information automatic acquisition unit 25A (automatic operation information acquisition) Acquisition) and a method of acquiring the CPU usage rate by executing the operation information test program in the operation information test program unit 25B (operation information test program execution acquisition).

First, the acquisition operation when the client terminal 2 receives a request for operation information from the image distribution server 1 will be described with reference to FIG.
In response to the operation information request from the image distribution server 1 (step 400), the client terminal control unit 21 of the client terminal 2 can acquire the operation information by the operation information automatic acquisition unit 25A (step 401), and can acquire the operation information. If it is (step 402: YES), the operation information is recorded and updated in the operation information recording table 25C (step 404), and the operation information is reported to the image distribution server 1 (step 405).
On the other hand, when the operation information cannot be acquired (step 402: NO), the operation information is acquired by the operation information test program unit 25B (step 403), and the process proceeds to step 404.

Next, with reference to FIG. 36, an operation when the client terminal 2 periodically acquires operation information will be described.
First, the client terminal control unit 21 of the client terminal 2 acquires the operation information by the operation information automatic acquisition unit 25A in accordance with the arrival of the periodic acquisition timing (step 410). Step 411: YES), the operation information is recorded and updated in the operation information recording table 25C (step 413). If the operation information cannot be acquired (step 411: NO), the operation information is acquired by the operation information test program unit 25B (step 412), and the process proceeds to step 413.

Then, the motion information recording table 25C and the motion information threshold value table 25D are compared (step 414). If the motion state has changed (step 415: YES), new motion information is stored in the image distribution server 1. In the same manner as when there is no change in the operation information (step 416), the process waits until the next acquisition timing (step 417).
In the above description, when the motion information cannot be acquired by the motion information automatic acquisition unit 25A, the acquired value is a numerical value exceeding 100%, a numerical value less than 0%, or a value other than a numerical value (character string Etc.).

  In this manner, the client terminal 2 uses the motion information automatic acquisition unit 25A and the motion information test program unit 25B to acquire and notify the motion information in response to a request from the image distribution server 1 or periodically. Therefore, the image distribution server 1 can accurately grasp the operation information of each client terminal 2.

In this embodiment, the case where the operation information test program is in the client terminal 2 has been described as an example. However, the operation information test program may be downloaded from the image distribution server 1 and used.
Further, although the usage rate of the CPU used in the computer of the client terminal 2 is used as the operation information, the usage status of the memory or the usage status of the communication network 10 may be used, or these may be combined.

[Fifth Embodiment]
Next, the operation of the image communication system according to the fifth embodiment of the present invention will be described with reference to FIG. FIG. 37 is a sequence diagram showing operations of the image communication system according to the fifth embodiment of the present invention.
In the present embodiment, a specific operation for acquiring environment information in the client terminal 2 will be described.

  The client terminal 2 acquires the environment information as a method for acquiring an operation input by the user of the client terminal 2 (environment information operation input acquisition) and automatically acquiring it by the environment information automatic acquisition unit 24B. There are a method (environmental information test program execution acquisition) and a method (environmental information test program execution acquisition) obtained by executing the environment information test program in the environment information test program unit 24C.

  When the client terminal control unit 21 is installed in the client terminal 2 or when the setting is changed, the client terminal control unit 21 performs CPU input (for example, P-II, P-) operated by the user of the client terminal 2. III) is acquired by the environment information operation input unit 24A (step 500), and is recorded in the environment information recording table 24D (step 501).

Even when such environmental information operation input acquisition is not performed, environmental information can be acquired by the following processing.
When participating in a conference, the client terminal control unit 21 of the client terminal 2 responds to a request for environment information from the image distribution server 1 (step 510), and uses the CPU capability obtained by acquiring the environment information operation input as the environment information. The information is read from the recording table 24D and reported to the image distribution server 1 as environment information (step 511).

  The image distribution control unit 11 of the image distribution server 1 determines whether or not the CPU capability obtained by acquiring the environment information operation input reported from the client terminal 2 is in the environment information table 16B (step 512), and there is a corresponding value. In such a case (step 512: YES), the client information management table 16D is updated (step 531) using the corresponding value of the environment information table 16B as the CPU capability of the client terminal 2 (step 530).

On the other hand, if there is no corresponding value (step 512: NO), the client terminal 2 is re-requested for environmental information (step 513).
The client terminal control unit 21 of the client terminal 2 that has received the re-request for the environment information uses the vendor ID from the CPUID data tab provided as CPU information by the CPU vendor in the OS information by the environment information automatic acquisition unit 24B. , CPU family, CPU model, and CPU stepping values are automatically acquired (step 514). If they can be acquired (step 515: YES), these values are recorded in the environment information recording table 24D. At the same time (step 516), it is reported to the image distribution server 1 as environmental information (step 517).

The image distribution control unit 11 of the image distribution server 1 determines whether or not the CPU capability reported from the client terminal 2 is in the environment information table 16B (step 520), and if there is a corresponding value (step 520: YES), The process proceeds to step 530 described above.
If there is no corresponding value (step 520: NO), the client terminal 2 is requested again for environmental information (step 521).

  If the client terminal control unit 21 of the client terminal 2 cannot automatically acquire environment information in step 515 (step 515: NO), or if a re-request for environment information is received from the image distribution server 1 (step 521), the environment information The test program unit 24C executes the environment information test program, measures the operating frequency of the CPU, and obtains test values (eg, 300 MHz, 600 MHz, 2.0 GHz, etc.) (step 522). Then, the test value is recorded in the environment information recording table 24D (step 523), and the test value is reported to the image distribution server 1 as environment information (step 524).

  In response to the report of the environment information (test value) from the client terminal 2, the image distribution control unit 11 of the image distribution server 1 corresponds to the CPU capability of the above report as the CPU capability of the client terminal 2 in step 530 described above. The client information management table 16D is updated using the value of the environment information table 16B to be executed (step 531).

  As described above, in the client terminal 2, the environment information operation input unit 24A, the environment information automatic acquisition unit 24B, or the environment information test program unit 24C is used to start the image communication or in response to a request from the image distribution server 1. Since the information is acquired and notified, the image distribution server 1 can accurately grasp the environmental information of each client terminal 2.

In this embodiment, the case where the operation information test program is in the client terminal 2 has been described as an example. However, the operation information test program may be downloaded from the image distribution server 1 and used.
Moreover, although the case where the CPU capability (P-II, P-III, P-IV, etc.) used in the computer of the client terminal 2 is used as environment information has been described as an example, it is used in the computer of the client terminal 2. The OS type (Windows 98, Windows XP, etc.), the memory type (500 MB, 1 GB, etc.), or the image drawing API type (Direct X8, Direct X9, etc.) may be used, or these may be combined.
Moreover, although the case where the client terminal 2 reports environmental information based on the request | requirement of the image delivery server 1 was demonstrated to the example, you may make it the client terminal 2 report to the image delivery server 1 autonomously.

It is a block diagram which shows the structure of the image delivery system concerning one embodiment of this invention. It is a functional block diagram which shows the function structure of an image delivery server. It is a functional block diagram which shows the function structure of a client terminal. It is an example of a structure of the delivery image quality threshold value table used with an image delivery server. It is an example of a structure of the environment information table used with an image delivery server. It is an example of a structure of the connection client number management table used with an image delivery server. It is an example of a structure of the client information management table used with an image delivery server. It is an example of a structure of the environment information recording table used with a client terminal. It is an example of a structure of the operation information recording table used with a client terminal. It is a sequence diagram which shows operation | movement of the image communication system concerning the 1st Embodiment of this invention. 1 is a configuration example of an image communication system according to a first embodiment of the present invention. It is a recording example of an environment information recording table (client terminal 2A). It is a recording example of a connected client number management table (image distribution server 1). It is a recording example of a client information management table (image delivery server 1). It is a recording example of an operation information recording table (client terminal 2A). It is a recording example of a client information management table (image delivery server 1). It is explanatory drawing which shows an image quality determination procedure. It is a recording example of a connected client number management table (image distribution server 1). It is a sequence diagram which shows operation | movement of the image communication system concerning the 2nd Embodiment of this invention. It is a sequence diagram which shows the continuation of operation | movement of the image communication system concerning the 2nd Embodiment of this invention. It is a structural example of the image communication system concerning the 2nd Embodiment of this invention. It is a recording example of an environment information recording table (client terminals 2A and 2B). It is a recording example of an operation information recording table (client terminal 2A). It is an example of a recording of an operation information recording table (client terminal 2B). It is a recording example of a connected client number management table (image distribution server 1). It is a recording example of a client information management table (image delivery server 1). It is a recording example of a client information management table (image delivery server 1). It is a recording example of a connected client number management table (image distribution server 1). It is a sequence diagram which shows operation | movement of the image communication system concerning the 3rd Embodiment of this invention. It is a structural example of the image communication system concerning the 3rd Embodiment of this invention. It is a recording example of an operation information threshold value table (client terminals 2A and 2B). It is a recording example of an operation information recording table (client terminal 2A). It is explanatory drawing which shows the confirmation procedure of the state change in a client terminal. It is a recording example of a client information management table (image delivery server 1). It is a sequence diagram which shows the operation | movement information acquisition operation | movement (sequential acquisition) in the client terminal 2 of the image communication system concerning the 4th Embodiment of this invention. It is a sequence diagram which shows the operation | movement information acquisition operation | movement (periodic acquisition) in the client terminal 2 of the image communication system concerning the 4th Embodiment of this invention. It is a sequence diagram which shows operation | movement of the image communication system concerning the 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image delivery server, 2, 2A, 2B, 2C ... Client terminal, 3A, 3B, 3C ... Image (terminal-> server), 4A, 4B, 4C ... Image (server-> terminal), 5A, 5B, 5C-Environment Information, 6A, 6B, 6C ... operation information, 10 ... communication network, 11 ... image distribution control unit, 12 ... communication interface unit, 13 ... image processing unit, 13A ... image receiving unit, 13B ... image sending unit, 13C ... image Codec section, 14 ... environment information management section, 15 ... operation information management section, 16 ... table management section, 16A ... distributed image quality threshold table, 16B ... environment information table, 16C ... connected client number management table, 16D ... client Information management table, 21... Client terminal control unit, 22... Communication interface unit, 23... Image management unit, 23 A. Image output unit 23C Image codec unit 24 Environment information management unit 24A Environment information operation input unit 24B Environment information automatic acquisition unit 24C Environment information test program unit 24D Environment information recording table 25 ... an operation information management unit, 25A ... an operation information automatic acquisition unit, 25B ... an operation information test program unit, 25C ... an operation information recording table, 25D ... an operation information threshold value table.

Claims (7)

A plurality of client terminals that transmit and receive images via a communication network and display received images, and images transmitted from the respective client terminals connected via the communication network according to the performance of the individual client terminals An image communication system comprising an image distribution server that converts the image quality into a distributed image and distributes each image,
The client terminal is
An environment information management unit for notifying the image distribution server of environment information indicating the static performance of the own device via the communication network;
An operation information management unit for notifying the image distribution server of operation information indicating the dynamic performance of the device via the communication network;
The image distribution server
The environment information indicating the static performance of the client terminal, the operation information indicating the dynamic performance of the client terminal, and the number of connections of the client terminals that distribute images from the image distribution server, notified from the client terminal And an image distribution control unit that determines the image quality of the image to be distributed to the client terminal based on the connection waiting number of the client terminal that is requesting connection to the image distribution server ;
An image communication system comprising: an image processing unit that converts an image quality of an image distributed to the client terminal based on the image quality. Connected via a communication network to a plurality of client terminals that transmit and receive images and display received images, and convert the images transmitted from each client terminal into image quality according to the performance of each client terminal An image distribution server that distributes each,
The environment information indicating the static performance of the client terminal, the operation information indicating the dynamic performance of the client terminal, and the image distributed from the image distribution server, notified from the client terminal via the communication network. An image distribution control unit that determines the image quality of an image to be distributed to the client terminal based on the number of connections of the client terminal and the connection waiting number of the client terminal that is requesting connection to the image distribution server ;
An image distribution server comprising: an image processing unit that converts an image quality of an image to be distributed to the client terminal based on the image quality. The image delivery server according to claim 2,
The environment information includes at least one information of CPU capability, OS type, memory type, and image drawing API type indicating the performance of the client terminal computer,
The image distribution server, wherein the operation information includes at least one of a CPU usage rate, a memory usage status, and a communication network usage status indicating the performance of the client terminal computer. The image delivery server according to claim 2,
The image distribution control unit determines at least one of an image size, a frame rate, and an image compression rate as the image quality. The image delivery server according to claim 2,
When determining the image quality, the image distribution control unit determines the image quality based on the number of image distribution destination client terminals connected via the communication network in addition to the environment information and the operation information. An image distribution server characterized by that. A plurality of client terminals that transmit and receive images via a communication network and display received images, and images transmitted from the respective client terminals connected via the communication network according to the performance of the individual client terminals An image communication method used in an image communication system including an image distribution server that converts image quality and distributes each image quality,
Notifying environment information indicating the static performance of the client terminal from the client terminal to the image distribution server via the communication network;
Notifying operation information indicating the dynamic performance of the client terminal from the client terminal to the image distribution server via the communication network;
The image distribution server distributes the environment information indicating the static performance of the client terminal, the operation information indicating the dynamic performance of the client terminal, and the image transmitted from the image distribution server, notified from the client terminal. Determining the image quality of the image to be distributed to the client terminal based on the number of connections of the client terminal and the connection waiting number of the client terminal requesting connection to the image distribution server ;
And a step of converting an image quality of an image to be delivered to the client terminal based on the image quality by the image delivery server. Connected via a communication network to a plurality of client terminals that transmit and receive images and display received images, and convert the images transmitted from each client terminal into image quality according to the performance of each client terminal To the computer of the image distribution server that distributes each,
The environment information indicating the static performance of the client terminal, the operation information indicating the dynamic performance of the client terminal, and the image distributed from the image distribution server, notified from the client terminal via the communication network. Determining the image quality of the image to be distributed to the client terminal based on the number of connections of the client terminal and the connection waiting number of the client terminal requesting connection to the image distribution server ;
A program for executing the step of converting the image quality of an image distributed to the client terminal based on the image quality.

Images