WO2012165066A1

WO2012165066A1 - Image distribution server and image distribution control method

Info

Publication number: WO2012165066A1
Application number: PCT/JP2012/060221
Authority: WO
Inventors: 敏貢福島
Original assignee: 富士フイルム株式会社
Priority date: 2011-05-31
Filing date: 2012-04-16
Publication date: 2012-12-06
Also published as: JP2012252381A

Abstract

An image distribution server comprises: a DB (22) for storing a first non-compressed image that corresponds to a specific webpage and a first compressed image in which the first non-compressed image has been compressed; a communication unit (21) for receiving a browser request from a mobile terminal (10) and acquiring a webpage; an analysis unit (23) for analyzing the acquired webpage; an image generator (24) for generating a second non-compressed image that can be displayed on the mobile terminal (10) from the acquired webpage on the basis of the analysis results; a difference image extraction unit (25) for comparing the first non-compressed image and the second non-compressed image and extracting as a difference image from the second image, an image in a difference region of the second non-compressed image that differs from the first non-compressed image; a compression unit (26) for compressing the extracted difference image; and a controller (29) for controlling the transmission of the compressed difference image and the first compressed image stored in the DB (22) to the mobile terminal (10) by the communication unit (21).

Description

Image distribution server and image distribution control method

The present invention relates to an image distribution server and an image distribution control method for converting a Web page for a PC (personal computer) into an image that can be displayed on a mobile terminal and distributing the image to the mobile terminal, and in particular, processing load on the server. The present invention relates to an image distribution server and an image distribution control method that can be reduced.

Conventionally, a mobile terminal such as a mobile phone, a smartphone, or a tablet PC is used as a client, and a Web page for PC acquired from a Web server is converted into an image that can be displayed on the mobile terminal, and the image is distributed to the mobile terminal. A distribution server is known (see Patent Document 1).

Also, when the requested image exists in the cache, it is known to distribute the image stored in the cache (see Patent Document 2).

Also, it is known that only a difference that is different from the image data transmitted immediately before is transmitted in order to reduce the amount of transmission data (see Patent Document 3).

JP 2004-220260 A JP-T-2004-518218 Special Table 2007-524286

By using a thin client type web page browsing technology that images a web page for a PC and distributes it to the mobile terminal, even if the mobile terminal is inferior in performance to the PC, the PC does not operate on the mobile terminal. Can be viewed in the same display form as when viewing a Web page for PC.

However, since the processing load on the server (image distribution server) that distributes images to mobile terminals is large, there is a problem that requests from a large number of mobile terminals cannot be received by one image distribution server. .

Patent Document 1 describes nothing about the processing load reduction of the image distribution server from the acquisition of the Web page for PC to the transmission of the image to the mobile terminal.

When the technology described in Patent Literature 2 is applied to the configuration of Patent Literature 1, if the same image exists in the cache, the processing load on the image distribution server can be reduced. When a part changes, the same image does not exist in the cache. In reality, even if the Web page has the same URL, part of the content of the Web page often changes, and the probability that the same image exists in the cache is reduced. Therefore, the processing load on the image distribution server is reduced. It cannot be reduced.

When the technology described in Patent Document 3 is applied to the configuration of Patent Document 1, it is possible to reduce the amount of transmission data by transmitting only the difference image to the mobile terminal, but the mobile terminal receives the data. Since it is necessary to store all the image data, it is not suitable for a thin client type system.

The present invention has been made in view of such circumstances, and provides an image distribution server and an image distribution control method capable of reducing the processing load of the server in a thin client type system for browsing web pages. Objective.

In order to achieve the above object, the present invention compresses a first uncompressed image corresponding to a specific Web page and a first uncompressed image that can be displayed on a mobile terminal. Storage means for storing the first compressed image, communication means for receiving a web page browsing request from the portable terminal, web page obtaining means for acquiring a web page requested to be browsed from the portable terminal, Analyzing means for analyzing the web page acquired by the web page acquiring means, and generating a second uncompressed image that can be displayed on the portable terminal from the acquired web page based on the analysis result by the analyzing means. Comparing the image generation means, the first uncompressed image stored in the storage means, and the second uncompressed image generated by the image generation means, A difference image extracting unit that extracts a difference area image different from the first uncompressed image from the second uncompressed image from the second uncompressed image, and the difference image extracting unit. A control unit that compresses the difference image, the first compressed image stored in the storage unit, and the difference image compressed by the compression unit to the portable terminal by the communication unit. And an image distribution server provided with a control means for performing the operation.

According to the present invention, when a web page browsing request is received from a portable terminal, the entire image (second uncompressed image) corresponding to the web page requested to be browsed is not compressed but stored in the storage unit. Since only the image in the difference area (difference image) different from the uncompressed image (first uncompressed image) that has been compressed is compressed, the entire image corresponding to the Web page requested to be browsed is compressed as in the past. Compared with the case where it does, the processing load (calculation amount) in an image delivery server can be reduced. In particular, a dynamic Web page (a part of the display content changes each time it is accessed, a Web page in which a part of the display content varies depending on the accessing user, etc.) or a Web page in which a part of the content is updated. Great effect when browsing. Further, according to the present invention, the first uncompressed image and the first compressed image obtained by compressing the first uncompressed image are stored in the storage unit, and an image corresponding to the Web page requested for browsing ( The second non-compressed image) is compared with the first non-compressed image stored in the storage means, so that the decompression process is unnecessary and the comparison can be started immediately, and the comparison process is performed by pixel comparison, etc. Can be easily performed.

In one embodiment, the storage unit stores a URL indicating the location of the specific Web page in association with the specific Web page, and the control unit stores the URL of the Web page requested to be browsed from the mobile terminal. It is determined whether or not it is stored in the storage means, and if the URL of the web page requested to be browsed is not stored in the storage means, control is performed so as not to extract and compress the difference image. The second compressed image generated by compressing the second uncompressed image by the compressing unit without transmitting the first compressed image and the compressed differential image to the portable terminal, and the communication unit To transmit to the mobile terminal.

In one embodiment, the control means determines whether or not the data amount of the difference image extracted by the difference image extraction means exceeds a threshold, and if the data amount of the extracted difference image exceeds the threshold, The difference image is controlled not to be compressed, and the second uncompressed image is compressed by the compression means without transmitting the first compressed image and the compressed difference image to the portable terminal. The second compressed image generated in this way is controlled to be transmitted to the portable terminal by the communication means.

When the difference area is large, the processing time (computation amount) when compressing (encoding) only the image (difference image) in the difference area and the process when compressing (encoding) the entire second uncompressed image Since the difference between the time (computation amount) is small and the first compressed image and the compressed difference image are distributed to the mobile terminal, the amount of communication data increases, so that the second uncompressed image as in this embodiment. If the second compressed image obtained by compressing the entire image is distributed, the amount of data transmitted to the portable terminal can be reduced, and the time required for image distribution can be reduced.

In one embodiment, the control means determines whether or not the amount of data of the extracted difference image is zero, and when the amount of data of the extracted difference image is zero, the compressed difference The image is not transmitted to the mobile terminal.

When there is no difference area, only the first compressed image stored in the storage means is transmitted to the mobile terminal, so that the time required for image distribution is compared with the case where the second uncompressed image is compressed. Is greatly shortened.

In addition, the present invention is an image distribution control method using a communication unit and a storage unit, and is a first uncompressed image that can be displayed on the mobile terminal and corresponds to a specific Web page. Storing a first compressed image obtained by compressing the first uncompressed image in the storage unit, receiving a web page browsing request from the portable terminal by the communication unit, and from the portable terminal A step of acquiring a web page requested to be browsed, a step of analyzing the acquired web page, and a second displayable on the mobile terminal from the acquired web page based on an analysis result of the web page A step of generating a non-compressed image, and comparing the first uncompressed image stored in the storage means with the generated second uncompressed image. Extracting from the second uncompressed image a difference image different from the first uncompressed image in the second uncompressed image from the second uncompressed image, and compressing the extracted difference image And a step of transmitting the first compressed image stored in the storage means and the compressed difference image to the portable terminal by the communication means.

The present invention also provides a program for causing an arithmetic device to execute the image distribution control method. The program can be provided by being recorded on various non-temporary recording media.

According to the present invention, it is possible to reduce the processing load of the image distribution server in the thin client type system for browsing web pages.

Schematic diagram showing how a web page for PC is viewed on a PC and mobile terminal Overall configuration diagram of a thin client type Web page browsing system The flowchart which shows the flow of the process example in a thin client type web page browsing system Explanatory drawing used to explain cache data retention Explanatory drawing used to explain whether or not there is cache data corresponding to the web page requested to be browsed Explanatory drawing used for description of a comparison between a non-compressed first uncompressed image held as cache data and a second uncompressed image generated from the acquired Web page Explanatory drawing used for explanation of extracting an image of a rectangular area inscribed by a difference image when the difference image is not rectangular Explanatory drawing used for explanation of compression when difference amount does not exceed threshold Explanatory drawing used for explanation of image distribution when difference amount does not exceed threshold Explanatory drawing used for explanation of compression and image distribution when difference amount exceeds threshold Explanatory drawing used for explanation of image distribution when difference amount is zero Explanatory drawing used for explanation of image display in portable terminal

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a state in which a PC web page is browsed using the display unit 14 of the mobile terminal 10 in the same manner as when a web page is browsed using the display unit 2 of a PC (personal computer) 1. It is a schematic diagram which shows. As shown in the figure, according to the Web page browsing system of this embodiment, the mobile terminal 10 can browse the Web page for the PC 1.

FIG. 2 is an overall configuration diagram showing an example of a Web page browsing system. As shown in the figure, the Web page browsing system of this example converts a mobile terminal 10 capable of displaying an image and a Web page for PC into an image that can be displayed on the mobile terminal 10, and converts the image to the mobile terminal. An image distribution server 20 that distributes to a PC and a Web server 30 that provides a Web page for a PC are included.

The mobile terminal 10 includes a communication unit 11 that communicates with the image distribution server 20, a processing unit 12 that controls each unit of the mobile terminal 10 according to a program, executes various processes, and an input unit 13 that receives an instruction input from a user. A display unit 14 capable of displaying an image and a database (DB) 15 for storing various types of information are included.

The portable terminal 10 and the image distribution server 20 are connected via an electric communication line such as the Internet, and the communication unit 11 of the portable terminal 10 and the communication unit 21 of the image distribution server 20 described later are connected via an electric communication line. Via the communication protocol determined in advance.

The processing unit 12 displays an image acquired from the image distribution server 20 via the communication unit 11 on the display unit 14 and executes a process according to a user instruction input received by the input unit 13.

The input unit 13 includes a power button, a number key, a cross key, a determination key, and the like (not shown), and the user can input various instructions to the mobile terminal 10 by operating the input unit 13. A touch sensor may be disposed on the front surface of the display unit 14 to serve as the input unit 13.

The display unit 14 includes a display device (for example, a liquid crystal display device) that can display an image, and performs display based on the image signal input from the processing unit 12.

The image distribution server 20 includes a communication unit 21 that communicates with the mobile terminal 10 and the Web server 30, and an image that can be displayed on the mobile terminal 10, and a specific Web page for PC (hereinafter referred to as “first Web page”). And an uncompressed image (hereinafter referred to as a “first uncompressed image”) and an image obtained by compressing the first uncompressed image by a later-described compression unit 26 (hereinafter referred to as a “first compressed image”). Database (DB) 22 to be analyzed, and an analysis unit that analyzes an arbitrary Web page for PC (hereinafter referred to as “second Web page”) that is requested to be browsed from the mobile terminal 10 and acquired from the Web server 30 by the communication unit 21. 23 and an image (hereinafter, “second uncompressed image” that can be displayed on the mobile terminal 10 from the acquired second Web page based on the analysis result of the second Web page by the analysis unit 23. And the second uncompressed image by comparing the first uncompressed image stored in the DB 22 with the second uncompressed image generated by the image generating unit 24. A difference image extraction unit 25 that extracts an image of a difference area different from the first uncompressed image from the second uncompressed image as a difference image, a compression unit 26 that performs image data compression, and image distribution And a control unit 29 that controls each unit of the server 20.

The image distribution server 20 and the Web server 30 are connected via an electric communication line such as the Internet, and the communication unit 21 of the image distribution server 20 and the communication unit 31 of the Web server 30 are connected in advance via an electric communication line. Communication is performed according to a predetermined communication protocol.

The DB 22 is composed of, for example, a known readable / writable disk, and stores various data (information). The control unit 29 of this example uses a part of the DB 22 as a so-called cache.

The analysis unit 23 and the image generation unit 24 are configured to include, for example, a CPU (Central Processing Unit), and execute so-called Web browser software. The image generation unit 24 executes an imaging process for converting PC screen information generated by a so-called rendering process into an image that can be displayed on the mobile terminal 10 that is the image distribution destination.

The difference image extraction unit 25 and the compression unit 26 are constituted by a CPU, for example. A part or all of these may be configured by an electronic circuit.

The format of compression (encoding) by the compression unit 26 is not particularly limited, and examples thereof include JPEG, PNG, and GIF. An irreversible format may be used.

The control unit 29 is constituted by a CPU and executes various processes according to a program.

Next, image transmission control processing by the control unit 29 will be described.

It is necessary to transmit a compressed (encoded) image (compressed image) to the mobile terminal 10. Therefore, when the image size is huge, it takes a long time to perform compression calculation processing. Conventionally, it takes a lot of time from acquiring a Web page to transmitting a compressed image to the mobile terminal 10. Therefore, the control unit 29 of the present embodiment basically compresses only the difference image (the second non-compressed image is a difference region image different from the first non-compressed image) by the compression unit 26. At the same time, the communication unit 21 transmits the compressed difference image (compression difference image) and the first compressed image stored in the DB 22 to the portable terminal 10. This reduces the load of compression processing in the image distribution server 20 and shortens the time required from the acquisition of the second Web page to the distribution of the image to the mobile terminal 10.

Further, the control unit 29 determines whether or not the URL of the second Web page requested to be browsed from the mobile terminal 10 is stored in the DB 22, and the URL of the second Web page requested to be browsed is stored in the DB 22. If not stored, the second image corresponding to the second Web page is controlled without performing extraction and compression of the difference image and without transmitting the first compressed image and the compressed difference image to the mobile terminal 10. Control is performed to transmit the second compressed image generated by compressing the uncompressed image to the mobile terminal 10 by the communication unit 21.

In addition, the control unit 29 determines whether or not the data amount of the uncompressed difference image extracted by the difference image extraction unit 25 exceeds the threshold value, and if the data amount of the uncompressed difference image exceeds the threshold value, The second compressed image generated by compressing the second uncompressed image by the compression unit 26 is transmitted to the portable terminal 10 by the communication unit 21 without transmitting the compressed image 1 and the compressed difference image of the first to the portable terminal 10. Control.

In addition, the control unit 29 determines whether or not the data amount of the extracted uncompressed difference image is zero. If the data amount of the extracted uncompressed difference image is zero, the control unit 29 determines whether or not the compressed difference image is zero. Control is performed so that only the first compressed image stored in the DB 22 is transmitted to the portable terminal 10 by the communication unit 21 without being transmitted to the portable terminal 10.

Further, the control unit 29 of this example calculates difference area position information that calculates position information (hereinafter referred to as “difference area position information”) of the difference area that is different from the first uncompressed image among the second uncompressed images. Has a calculation function. The difference area position information indicates the position of the difference area on the second uncompressed image. Further, when transmitting the compressed difference image (compressed difference image) to the mobile terminal 10, the control unit 29 of the present example, together with the compressed image (first compressed image and compressed difference image), the difference area Send metadata including location information. Therefore, the portable terminal 10 can easily superimpose the difference image on the first uncompressed image based on the difference area position information in the metadata after expanding the first compressed image and the compressed difference image. .

In addition, the control unit 29 of the present example extracts user interface information (hereinafter referred to as “UI information”) from the Web page, and the positional information on the second uncompressed image of the UI information (hereinafter referred to as “UI positional information”). UI position information calculation function for calculating And the control part 29 of this example transmits the metadata containing UI information and UI position information with the compressed image with respect to the portable terminal 10. FIG. Therefore, after displaying the image, the mobile terminal 10 can easily execute a process according to the user's input operation based on the UI information and the UI position information in the metadata.

FIG. 3 is a flowchart showing a flow of a processing example in the thin client type Web page browsing system. The processing in the image distribution server 20 is executed by the control unit 29 according to a program. Further, the processing in the mobile terminal 10 is executed by the processing unit 12 according to a program. These programs are recorded on a non-transitory computer-readable medium such as a ROM.

The image distribution server 20 holds cache data corresponding to a specific Web page (first Web page) in advance by the DB 22 (step S2).

As shown in FIG. 4, the cache data 80 includes a URL (Uniform ResourceatorLocator) 81 of the first Web page and an image that can be displayed on the mobile terminal 10 and corresponds to the first Web page. A compressed image 82 and an image 83 (first compressed image) obtained by compressing the first uncompressed image 82 are included. The control unit 29 stores the cache data 80 in the DB 22. The URL is information indicating the location of the Web page. The control unit 29 identifies the web page by the URL.

The input unit 13 of the mobile terminal 10 receives an input of a URL of an arbitrary Web page (second Web page) from the user, and the communication unit 11 of the mobile terminal 10 browses the Web page to the image distribution server 20. A request is transmitted (step S4). The URL received from the user is added to the browsing request.

When the communication unit 21 receives a web page browsing request from the mobile terminal 10, the control unit 29 acquires the second web page requested to be browsed from the mobile terminal 10 from the web server 30 by the communication unit 21 (step S6). ).

Next, the image distribution server 20 analyzes the acquired second Web page by the analysis unit 23 (step S8).

Next, the image distribution server 20 uses the image generation unit 24 to generate an image (second uncompressed image) that can be displayed on the mobile terminal 10 from the second Web page based on the analysis result of the analysis unit 23. (Step S10).

Next, the control unit 29 determines whether or not cache data corresponding to the second Web page exists (step S12). In this example, as shown in FIG. 5, the control unit 29 stores the URL (http://www.site1.co.jp in this example) of the Web page requested to be browsed from the mobile terminal 10 in the DB 22. Whether or not the first uncompressed image and the first compressed image corresponding to the second Web page exist is determined by determining whether or not the image is present (existing in the cache data 80). Note that if a query is added to the URL, whether to ignore the query can be set in the DB 22.

When cache data corresponding to the second Web page exists, the difference image extraction unit 25 generates the first uncompressed image 82 stored in the DB 22 and the image generation unit 24 as shown in FIG. Compared with the second uncompressed image 84, the second uncompressed image 84 and an image of the difference area 86 (86a, 86b, 86c) different from the first uncompressed image 82 are A difference image is extracted from the uncompressed image 84 (step S14). If there is no cache data corresponding to the second Web page, the process proceeds to step S24.

Since the difference image extraction unit 25 performs comparison between uncompressed images, there is no need for decompression, the compression format may be irreversible, or the comparison may be simply performed for each pixel (pixel). The difference image extraction unit 25 of this example determines a continuous area of pixels that do not match the first uncompressed image in the second uncompressed image as a difference area 86 (86a, 86b, 86c).

As shown in FIG. 7, when the difference area 86 is not rectangular, the difference image extraction unit 25 detects a rectangular area inscribed by the difference area 86, and uses the image in this rectangular area as a difference image 87 to generate a second image. The uncompressed image 84 may be extracted.

Further, the difference image extraction unit 25 calculates (acquires) the coordinates (difference area position information) of the difference area 86 in the second uncompressed image 84 and transmits the position information to the mobile terminal 10. As part of When the difference area 86 is a rectangle, the difference image extraction unit 25 may acquire, for example, two of the rectangle start point coordinates (upper left coordinates) and end point coordinates (lower right coordinates). The position information of the difference area 86 indicates the position of the difference area 86 in the second uncompressed image 84 (and the position of the difference area 86 in the first uncompressed image 82).

Next, the control unit 29 determines whether or not the data amount (difference amount) of the image (difference image) of the extracted difference region 86 (86a, 86b, 86c) exceeds a threshold value (step S16).

The control unit 29 of this example calculates the size (area) of the difference area 86 in the second uncompressed image 84 as the difference amount. For example, the control unit 29 may count the total number of pixels (number of pixels) in the difference area 86 as the area. In the example illustrated in FIG. 6, the control unit 29 calculates the sum of the areas of the difference regions denoted by

reference numerals

86 a, 86 b, and 86 c and compares the sum with a threshold set in advance in the DB 22 of the image distribution server 20. For example, the control unit 29 sets 20% of the area of the second uncompressed image 84 as the threshold value. The control unit 29 may simply set the number of pixels as a threshold value. However, the control unit 29 compresses (encodes) only the difference images (87a, 87b, and 87c in FIG. 8) rather than compressing (encoding) the entire second uncompressed image 84 if it is equal to or less than the threshold value. However, it is necessary to set a threshold value so that the processing time (calculation amount) in the image distribution server 20 is reduced.

If the difference amount does not exceed the threshold value (difference amount ≦ threshold value), the control unit 29 further determines whether or not the difference amount is zero (step S18). When the difference amount is not zero (0 <difference amount ≦ threshold value), as shown in FIG. 8, the control unit 29 includes images of the

difference areas

86 a, 86 b, 86 c in the second uncompressed image 84. Only the

difference images

87a, 87b, 87c are compressed by the compression unit 26 of the image distribution server 20, respectively, and

compressed difference images

88a, 88b, 88c are generated (step S20).

Then, as shown in FIG. 9, the image distribution server 20 stores the first compressed image 83 stored in the DB 22, the compressed difference image 88 (88 a, 88 b, 88 c), and the metadata 89. It transmits to the portable terminal 10 by the communication part 21 (step S22). The metadata 89 includes difference area position information describing the coordinate position of the difference area 86 (86a, 86b, 86c) in the second uncompressed image. That is, the metadata 89 includes difference area position information describing the coordinate position of the difference area 86 in the first uncompressed image 83.

When the difference amount exceeds the threshold value, the image distribution server 20 compresses all the second uncompressed images 84 generated by the image generation unit 24 by the compression unit 26 as shown in FIG. S24) The second compressed image 85 generated by the compression is transmitted to the mobile terminal 10 by the communication unit 21 (step S26).

When the difference amount is zero, the image distribution server 20 transmits the first compressed image 83 stored in the DB 22 to the mobile terminal 10 by the communication unit 21 as shown in FIG. 11 (step S28). .

The mobile terminal 10 expands the image received from the image distribution server 20, and displays the expanded image on the display unit 14 of the mobile terminal 10 as shown in FIG. 12 (step S30). When the mobile terminal 10 receives the first compressed image 83 and the compressed difference image 88 from the image distribution server 20, as shown in FIG. 12, the entire display area of the first uncompressed image 82 is displayed. Of these, the

difference areas

86a, 86b, 86c designated by the difference area position information of the metadata are overwritten with the expanded

difference images

87a, 87b, 87c and displayed.

Note that the images (first uncompressed image and first compressed image) stored as cache data in the DB 22 may not be fixed.

First, the image distribution server 20 stores (holds) the browsing request history (communication log) of the Web page received from the mobile terminal 10 in the DB 22, and the control unit 29 determines the DB 22 based on the history. There is a mode of determining an image to be stored (held) as cache data. For example, the control unit 29 generates a history including a URL indicating the location of the web page in the DB 22, and based on the URL in the history, a certain number of web pages (or in the order in which the number of browsing requests from the mobile terminal 10 is large) Site) is selected, and images corresponding to the selected plurality of Web pages (or sites) are stored in the DB 22 as first uncompressed images 82, respectively.

Second, the image distribution server 20 stores (sets) a specific URL as setting information in the DB 22 of the image distribution server 20 in advance, and stores (holds) an image corresponding to the setting information (URL) in the DB 22. There is a mode to keep.

Also, the timing for starting the retention of cache data is not particularly limited. For example, holding of cache data is started when a certain time has elapsed since the system started operation.

The present invention is not limited to the examples described in the present specification and the examples illustrated in the drawings, and various design changes and improvements may be made without departing from the scope of the present invention.

This specification discloses the following inventions.

Invention 1: A first non-compressed image that can be displayed on a mobile terminal and stores a first non-compressed image corresponding to a specific Web page and a first compressed image obtained by compressing the first non-compressed image Storage means, a communication means for receiving a web page browsing request from the portable terminal, a web page obtaining means for obtaining a web page requested to be browsed from the portable terminal, and a web acquired by the web page acquiring means. Analysis means for analyzing a page, image generation means for generating a second uncompressed image that can be displayed on the mobile terminal from the acquired Web page based on the analysis result by the analysis means, and storage means The stored first uncompressed image is compared with the second uncompressed image generated by the image generating means, and the second uncompressed image is compared with the second uncompressed image. Differential image extraction means for extracting an image of a difference area different from the one uncompressed image from the second uncompressed image as a difference image; compression means for compressing the difference image extracted by the difference image extraction means; Image distribution comprising: control means for controlling the first compressed image stored in the storage means and the difference image compressed by the compression means to be transmitted to the portable terminal by the communication means server.

Invention 2: The storage means stores a URL indicating the location of the specific Web page in association with the specific Web page, and the control means stores the URL of the Web page requested to be browsed from the portable terminal. It is determined whether or not the URL of the web page requested to be browsed is not stored in the storage unit, and control is performed so as not to extract and compress the difference image. The second compressed image generated by compressing the second non-compressed image by the compression unit without transmitting the first compressed image and the compressed difference image to the portable terminal is transmitted by the communication unit. The image delivery server according to claim 1, wherein the image delivery server performs control of transmission to a portable terminal.

Invention 3: The control means determines whether or not the data amount of the difference image extracted by the difference image extraction means exceeds a threshold. If the data amount of the extracted difference image exceeds the threshold, the difference Control is performed so as not to compress the image, and the second uncompressed image is generated by compressing the second uncompressed image by the compression means without transmitting the first compressed image and the compressed difference image to the portable terminal. The image distribution server according to

claim

1 or 2, wherein control is performed to transmit the second compressed image that has been performed to the portable terminal by the communication unit.

Invention 4: The control means determines whether or not the data amount of the extracted difference image is zero, and if the data amount of the extracted difference image is zero, the control unit determines the compressed difference image The image distribution server according to claim 3, wherein the image distribution server is not transmitted to the portable terminal.

Invention 5: When the said control means transmits the said compressed difference image with respect to the said portable terminal, the positional information on the difference area different from a said 1st uncompressed image among the said 2nd uncompressed image The image delivery server according to

claim

1 or 2, wherein the communication means transmits the information to the portable terminal.

Invention 6: When the difference area is not rectangular, the difference image extraction means detects a rectangular area inscribed by the difference area, and extracts the image of the rectangular area as the difference image from the second uncompressed image. 6. The image delivery server according to any one of inventions 1 to 5.

Invention 7: The storage means stores a history of browsing requests for Web pages received from the portable terminal, and the control means stores the first uncompressed information stored in the storage means based on the history. 7. The image distribution server according to any one of inventions 1 to 6 for determining an image.

Inventions 8 to 14: Method inventions corresponding to Inventions 1 to 7, respectively.

Inventions 15 to 21: Inventions of programs corresponding to Inventions 8 to 14, respectively. The invention of the program can be provided by being recorded on various recording media.

DESCRIPTION OF SYMBOLS 10 ... Portable terminal, 20 ... Image delivery server, 21 ... Communication part, 22 ... DB, 23 ... Analysis part, 24 ... Image generation part, 25 ... Difference image extraction part, 26 ... Compression part, 29 ... Control part, 30 ... Web server, 80 ... cache data, 81 ... URL, 82 ... first uncompressed image, 83 ... compressed first non-compressed image (first compressed image), 84 ... second uncompressed image, 85 ... compressed second uncompressed image (second compressed image), 86 (86a, 86b, 86c) ... difference area, 87 (87a, 87b, 87c) ... difference image, 88 (88a, 88b, 88c) ... compressed differential image (compressed differential image)

Claims

Storage means for storing a first non-compressed image that can be displayed on a portable terminal and corresponding to a specific Web page, and a first compressed image obtained by compressing the first non-compressed image When,
Communication means for receiving a web page browsing request from the portable terminal;
Web page acquisition means for acquiring a Web page requested to be browsed from the mobile terminal;
Analyzing means for analyzing the Web page acquired by the Web page acquiring means;
Image generating means for generating a second uncompressed image that can be displayed on the mobile terminal from the acquired web page based on the analysis result by the analyzing means;
The first uncompressed image stored in the storage unit is compared with the second uncompressed image generated by the image generation unit, and the first uncompressed image among the second uncompressed images is compared. Differential image extraction means for extracting, from the second non-compressed image, an image of a difference area different from the one uncompressed image as a differential image;
Compression means for compressing the difference image extracted by the difference image extraction means;
Control means for performing control to transmit the first compressed image stored in the storage means and the difference image compressed by the compression means to the portable terminal by the communication means;
An image distribution server with
The storage means stores a URL indicating the location of the specific Web page in association with the specific Web page;
The control means determines whether or not the URL of the web page requested to be browsed from the portable terminal is stored in the storage means, and the URL of the web page requested to be browsed is stored in the storage means. If not, control is performed so as not to extract and compress the difference image, and the second compressed image is not transmitted to the portable terminal without transmitting the first compressed image and the compressed difference image. The image distribution server according to claim 1, wherein control is performed to transmit the second compressed image generated by compressing the compressed image to the portable terminal by the communication unit.
The control unit determines whether or not the data amount of the difference image extracted by the difference image extraction unit exceeds a threshold value. If the data amount of the extracted difference image exceeds a threshold value, the control unit compresses the difference image. The first non-compressed image is generated by compressing the second non-compressed image by the compression means without transmitting the first compressed image and the compressed difference image to the portable terminal. The image distribution server according to claim 1, wherein control is performed to transmit the two compressed images to the portable terminal by the communication unit.
The control means determines whether or not the amount of data of the extracted difference image is zero, and when the amount of data of the extracted difference image is zero, the compressed difference image is displayed as the portable terminal. The image distribution server according to claim 3, wherein the image distribution server is not transmitted to the server.
The control means, when transmitting the compressed difference image to the mobile terminal, position information of the difference area different from the first uncompressed image among the second uncompressed image, The image distribution server according to claim 1, wherein the image distribution server transmits the information to the portable terminal by communication means.
The difference image extraction means detects a rectangular area inscribed by the difference area when the difference area is not rectangular, and extracts an image of the rectangular area as the difference image from the second uncompressed image. The image delivery server according to any one of 1 to 5.
The storage means holds a history of browsing requests for web pages received from the mobile terminal,
The image delivery server according to any one of claims 1 to 6, wherein the control unit determines the first uncompressed image to be stored in the storage unit based on the history.
An image distribution control method using communication means and storage means,
Arithmetic unit is
A first uncompressed image that can be displayed on the portable terminal and corresponds to a specific Web page, and a first compressed image obtained by compressing the first uncompressed image is stored in the storage unit. Memorizing steps,
Receiving a web page browsing request from the portable terminal by the communication means;
Obtaining a web page requested to be browsed from the mobile terminal;
Analyzing the acquired web page;
Generating a second uncompressed image that can be displayed on the mobile terminal from the acquired Web page based on the analysis result of the Web page;
The first uncompressed image stored in the storage unit is compared with the generated second uncompressed image, and the first uncompressed image among the second uncompressed images. Extracting an image of a difference area different from the second uncompressed image as a difference image;
Compressing the extracted difference image;
Transmitting the first compressed image stored in the storage unit and the compressed difference image to the portable terminal by the communication unit;
An image delivery control method for executing.
Arithmetic unit is
Storing a URL indicating the location of the specific Web page in association with the specific Web page;
Determining whether the URL of the web page requested to be browsed from the portable terminal is stored in the storage means;
Compressing the second uncompressed image to generate a second compressed image;
If the URL of the web page requested to be browsed is not stored in the storage unit, the second compressed image is not transmitted to the portable terminal without transmitting the first compressed image and the compressed difference image. Transmitting to the portable terminal by communication means;
The image delivery control method according to claim 8, wherein:
Arithmetic unit is
Determining whether the data amount of the extracted difference image exceeds a threshold;
Compressing the second uncompressed image to generate a second compressed image;
When the data amount of the extracted difference image exceeds a threshold value, the second compressed image is transmitted to the portable terminal by the communication means without transmitting the first compressed image and the compressed difference image to the portable terminal. Sending to the device;
The image delivery control method according to claim 8 or 9, wherein:
Arithmetic unit is
Determining whether the data amount of the extracted difference image is zero;
If the data amount of the extracted difference image is zero, not transmitting the compressed difference image to the mobile terminal;
The image delivery control method according to claim 10, wherein:
A computer-readable recording medium storing a program for causing an arithmetic device to execute the image delivery control method according to any one of claims 8 to 11.