WO2002103980A2

WO2002103980A2 - Method and system for broadcasting digital images

Info

Publication number: WO2002103980A2
Application number: PCT/FR2002/002021
Authority: WO
Inventors: Raphaël RAMIREZ
Original assignee: Picturelan
Priority date: 2001-06-14
Filing date: 2002-06-13
Publication date: 2002-12-27
Also published as: FR2826213B1; FR2826213A1; WO2002103980A3

Abstract

The invention relates to a method and broadcasting system for sending digital images to a terminal (2; 3; 4) over a network which is at least partially public. Said terminal comprises at least one display device and the system comprises a centre (20) with a server (5) with a connection (13) to a storage unit (7) in which the digital images are stored. The system further comprises a means for calculating a new image from the stored image, which is adapted to the characteristics of the terminal display and means for generating a temporary file with the new image which is transmitted to the terminal. The information relating to the type and the characteristics of the terminal display for calculating the adapted image are defined at the level of the centre (20).

Description

METHOD AND SYSTEM FOR BROADCASTING DIGITAL IMAGES

Field of the invention

The present invention relates to the field of broadcasting digital images over electronic networks. It relates more particularly to a system and a method enabling the broadcasting and display of digital images on terminals having different display devices.

Prior art

With the development of electronic networks, such as the Internet, the dissemination of images alone or integrated into documents is currently very widespread. A large part of the sites already present on the Internet offer the posting of such documents.

However, in the computer field, files containing images are known to be very large files in terms of occupied memory space. This is why there are companies, notably present on the Internet, whose main activity is to offer, via servers, image bank services or the like, or, for example, newspapers or magazines in online, which regularly broadcast content illustrated with images. However, even if these companies have high-capacity storage equipment, the management of memory space still remains a problem. Indeed, this type of equipment has a cost which is naturally related to the volume of storage it presents. It is therefore advisable to always be in search of an optimization of the occupation of the memory space. The management of memory space for companies that store and distribute digital images is today encountering a new problem which is linked to the increasing diversity of display formats presented by the devices which can receive and display digital images. In fact, in addition to terminals of the personal computer type, there are many devices on the market such as mobile telephones or personal digital assistants with which images can be received via an electronic network. In the field of mobile phones, for example, there are currently over a hundred models, all of which have a different screen or display format.

Consequently, companies which make digital images available to users must either restrict the dissemination of these images to a limited number of terminals, or further increase their storage capacity in order to be able to provide the user with a large number of files of the same image, each file corresponding to the image adapted to the specific display characteristics of a device. These two solutions each have drawbacks. Indeed, the solution of limiting the supply of images to a few devices appears to be very risky commercially. The exclusion of certain devices would limit the broadcasting market for society and taking into account new formats would be very difficult because it would be necessary to exclude old models still in use. On the other hand, the second solution which consists in increasing the storage capacity as new formats appear, already seems unrealistic in view of the number of display formats which exist and which should increase considerably in the next years. Such permanent investments would be incompatible with the commercial development of the company. Another solution consists in equipping the terminals with one or more on-board software which processes the images according to the format and display characteristics of the terminal. However, this solution has a major drawback. Indeed, in this case, each terminal must have in memory the image processing software (s), which implies increasing the memory capacity (random access memory "RAM" and read-only memory "ROM") in order to be able to store and implement these programs. However, with regard in particular to terminals of the mobile telephone or personal assistant type, this required increase in memory capacity undeniably leads to an increase in the size and the cost of manufacturing the device which is not admissible for manufacturers. In addition, each on-board software can only process the specific image format defined by the software publisher, so that the terminal must include as much software as there are specific image formats.

Object and brief description of the invention

The present invention aims to remedy the aforementioned drawbacks and to propose a technical solution which makes it possible, from a single image file, to distribute this image in a suitable format whatever the display format and the type of terminal used without need to increase the storage capacity of images.

These objects are achieved by a method of broadcasting digital images to allow a user, who has a terminal comprising at least one display device, to receive and display the digital images, said digital images being stored in a image distribution center accessible by the user via an at least partially public network, characterized in that it comprises the following steps: a) sending a request for an image by the user's terminal to the image distribution center, b) extracting data relating to the image identified in the request, c) querying a database comprising display information of the terminal, d) detection of the type and display characteristics of the user's terminal, e) calculation of the new data relating to the image as a function of the data extracted from the image as well as of the type and display characteristics of the detected terminal, f) generation of a temporary image file from the new calculated data, and g) sending of the generated file to the user terminal for viewing. The digital images can be still images or video sequences.

According to one aspect of the invention, step d) further comprises a prior step of searching for and recovering a corresponding temporary file, said file having been generated during a similar previous request coming from a terminal having the same characteristics. This avoids recalculating and generating a suitable image if this had already been done recently.

According to another aspect of the invention, the method further comprises a step of determining the display options as a function of the type of terminal. The display options can be determined for each image or for a group of images depending on the type of terminal.

The display options are stored in a database of the image distribution center. More specifically, in step g), the temporary file is associated with display format information according to the display options and the user's terminal.

According to yet another aspect of the invention, the method further comprises an image processing step which includes geometric and colorimetric transformations of the image.

According to an embodiment of the present invention, the user request is in the form of a universal address and an index is associated with the name of the image in the request which automatically triggers said steps b) to g).

Alternatively, the user request is in the form of a universal address corresponding to a file stored in the image distribution center, said file comprising instructions for triggering said steps b) to g). In steps a) and g) the data can be transmitted in encrypted form.

According to a characteristic of the invention, the terminal is a mobile telephone, a personal digital assistant, a web terminal or a television set comprising means of access to the network. According to another particular characteristic of the invention, the network is the Internet.

The present invention also relates to a broadcasting system for sending digital images to an at least partially public network to a terminal comprising at least one display device, said system comprising a center equipped with a server in connection with a unit. storage in which at least the digital images are stored, characterized in that the center further comprises means for defining the type and display characteristics of the terminal, means for calculating, from the stored image, a new image adapted to the type and display characteristics of the terminal and means for generating a temporary file of the new image.

More specifically, the storage unit comprises a first volume for storing the original images and a second volume for storing a database of the characteristics of the terminals. In the first volume, the images are stored as a file and in the second volume, additional data of display options associated with one or more images are stored in the form of a database. The storage unit further includes a third storage volume for temporarily storing the generated image files.

According to one embodiment of the invention, the system further comprises an electronic document distribution center which includes a server linked to a document storage unit.

According to a particular aspect of the invention, the system further comprises a control and processing device in connection with the server of the image broadcasting center. This device can be located at the image distribution center or the electronic document distribution center. The control and processing device comprises means for determining display options associated with one or more images and processing means corresponding to geometric and colorimetric transformations of the image.

The server or servers present in the system according to the invention may include encryption and decryption means for the transmission of data.

Brief description of the drawings

Other characteristics and advantages of the invention will emerge from the following description of particular embodiments of the invention, given by way of nonlimiting examples, with reference to the appended drawings, in which:

FIG. 1 is a global schematic view of the system according to the invention, FIGS. 2A and 2B are a flow diagram illustrating the steps of the method according to the invention,

- Figures 3A and 3B are a flowchart showing steps of image selection and modification of display options in accordance with an embodiment of the invention, - Figure 4 is a flowchart showing steps of processing image in accordance with an embodiment of the invention,

FIGS. 5A to 5C show examples of display option interfaces, and

- Figure 6 shows an example of an image processing interface according to the invention.

Detailed description of the embodiments of the invention

The present invention is based on the use of image storage equipment in digital form associated with a server as dissemination means for the sale or the provision of so-called "online" images. ie offered to users of a public network such as the so-called "Internet" network.

For the sake of simplification, the open or public network through which the various parties intervene in the image broadcasting operation will be simply referred to as "network" in the following description. On the other hand, in order not to unnecessarily burden the description of the invention, it will hereinafter be described in relation to a system in which the users have, as reception terminal, a fixed terminal, such as a personal computer connected to the spider web known as "world wide web" and subsequently referred to as "web terminal", a mobile phone or a personal digital assistant (PDA). However, the present invention generally applies to all terminals which include means for receiving and displaying digital images which are accessible via an electronic network. By way of example, the invention also applies to devices which allow access and display of web pages on a television or any other device. Figure 1 is an overall view of a system 1 according to the invention showing the relationships between the different parties involved according to the method of the invention. The parties which intervene mainly during an image broadcasting operation are a user equipped with a reception terminal and an image storage, processing and broadcasting center which can possibly be managed by a company which wishes to update the disposition of one or more users of photos or documents including images. The companies likely to implement the invention can be either a photo development laboratory, a press organization ...

The company which is in charge of the storage, the processing and the distribution of the images will be called "broadcasting company" thereafter. The purpose of the present invention is to provide these broadcasting companies with a technical solution which enables them to provide, from a single original image file, images adapted to the display characteristics of the terminal, whatever the terminal used.

To have access to the network and therefore to the image server, the user has a terminal which can be fixed, such as a personal computer type web terminal 4 equipped with a modem and navigation software called "browser "thereafter. The user can also be provided with a mobile terminal, such as a mobile telephone 2 or a personal digital assistant 3 (PDA) for which the operator offers a network access service or the like such as "WAP" services. " for example. The broadcasting company has a center 20 for storing, processing and broadcasting images which includes a server 5 essentially in charge of authentication and processing requests sent by users, a storage unit 7 linked to the server 5. More specifically, the server 5 is intended to perform the functions of receiving and interpreting requests, accessing databases and images, calculating, generating and managing the requested images. It also offers functions which allow an operator to manage and organize a library of images remotely. Thus, the server 5 can be a single machine which performs all of these functions or else a plurality of servers, each dedicated to one of the above functions. In addition, in order to compensate for possible failures of one of the components of the system or else to distribute the load in the system, the server 5 or the plurality of servers performing the functions described above can or can be duplicated ) in the system in a redundant manner (operation of servers known as "cluster" or "load balancing").

The storage unit 7 mainly comprises a first storage volume 71 on which all digital images are transferred, stored and updated and a second storage volume 72 intended to keep a database which not only gathers information useful, such as the type and characteristics of display and / or image format supported, relating to each known terminal or family of terminals which is likely to be used to send a request to the server 5, but also the options default or as determined by an operator and associated with the images. The storage volume 72 is also intended to store data of dimensions of the original image which will be used during the calculations of the image adapted to the terminal. For this purpose, the data is extracted from the image when it is initially downloaded by an operator on the center 20. During this operation, the image, whatever its original format, is transformed and stored with the same resolution in an image file according to a standard for storing still images of the "JPEG" type (Group Reunited). Photographic Image Experts), for example. This transformed image will be called "original image" thereafter. The data concerning the dimensions of the image which is stored in the database 72 are then extracted from this file.

The storage unit 7 also comprises a third storage volume 73, called a "cache", which is used to store, only temporarily, the image file generated during a request by the center 20 and which makes it possible to re-use subsequently this file if, in a determined time interval, a similar request relating to the same image and emanating from the same type of terminal is sent again.

Images are not always transmitted alone. They are often part of a document which can be stored and listed on an additional volume (not shown) of the storage unit 7. However, it may be advantageous to separate the storage of documents and images. This is why the system according to the invention can also include a document distribution center 30 such as, for example, documents intended for press articles. In this case, the center 30 is called "content provider". For this, the center 30 includes a server 8 linked to a storage unit 9 on which the documents are stored. The documents with which images are associated include for each of these images a specific link which corresponds to a request for the image from the server 5. As illustrated in FIG. 1, the storage unit 9 can include document files adapted to the web terminal format, personal digital assistant, mobile phone ..., or so-called "multi-format" files, that is to say including all the data to display the document on any type of terminal, the server 8 of the center 30 subsequently determining the format as a function of the terminal used.

The center 30 could also simply be an image broadcasting site in relation to the center 20 which hosts images which are offered on the server 8 of the center 30.

The images can therefore be stored on the storage volume 71 of the center 20 and transmitted to the user with the document in a format suitable for his terminal according to the method of the invention which will be described later. With the configuration of the system 1 represented in FIG. 1, the display of a document comprising one or more images stored on the volume 71 is carried out in several stages, namely a first stage consisting in sending from the terminal 2, 3 or 4 and respectively via the link 16, 17 or 18 a request to the server 8 to receive and display a document stored on the volume 9. The terminal concerned then receives the document containing at least one link to an image available from the server 5 from the center 20. The terminal then transmits to the server 5 a request relating to the image concerned by the link 10, 11 or 12 depending on the terminal used. The image request is interpreted by the server 5 which returns to the terminal the image adapted to its display characteristics. As shown in Figure 1, the centers 20 and 30 may be physically at different locations. However, the resources of the centers 20 and 30 can be brought together on a single site, the content provider and the image storage, processing and distribution center being managed by a single company. The center 30 or content provider also has a control and processing device 6 in connection, via a line 19, with the server 5 itself. This device essentially allows an operator of the center 30 to manage the images stored on the volume 71 of the center 20 (downloading of new images to the center 20, deletion of images stored on the center 20 ...) and to apply to these options display and / or treatments. In the example illustrated in FIG. 1, the device 6 is in connection 21 with the server 8. This connection 21 is used by the device 6 only for transmitting the links of the image in the document, that is to say say to include in the documents stored on volume 9 the references of the image file ("image.kim") on the center 20 which will then be taken up by the user terminal to formulate the image request (s) in the center 20.

In a system where there would only be the center 20, the device 6 would be included in the center 20. The communication lines 12 and 18 of the web terminal are bidirectional transmission lines of the electrical, optical, or wired type ( local radio loop, infrared link, etc.). The communication lines 10, 16 and 11, 17 respectively of the mobile telephone and the personal digital assistant are at least partially radio frequency (RF) links when these are not connected to a fixed terminal of the personal computer type by example to access the network.

The servers 5 and 8 represented in the system of FIG. 1 conventionally comprise means of connection to the network, storage means and processing means. These servers 5 and 8 can further comprise encryption and decryption means in order to carry out data transmissions in coded form.

The method of the invention which is implemented by a computer program in the system of FIG. 1 will be described in relation to the flow diagram of FIGS. 2A and 2B.

After the terminal has received a document from a content provider 30, including a link to an image stored on a broadcasting server 20, the interpretation of this document by the terminal generates, in a first step ST1, a request to server 5 of center 20. In the case of a system where the image would be directly requested by the user, that is to say without going through a content provider, step ST1 would then consist in the sending by the user of a request directly to the server 5 of the center 20 by means of its terminal. The function of the image request sent to the server 5 is to request the server to transmit to the user terminal an image chosen from the plurality of stored images. This request can be in the form of a universal address allowing direct access to the server 5 supplemented by the directory and the name of the image sought. Such a request could be for example:

"Http://societedediffusion.com/repertoire_client/image.kim"

According to one embodiment of the invention, an index is associated with the name of the image in the request. This index can be found in the query in any form of character string such as the extension ".kim" used in the example query above. When the index is recognized by the program in a step ST2 of reception of the request by the server 5, the program automatically triggers steps ST3 to STIO which will make it possible to transmit to the terminal an image suitable for displaying the latter. According to another embodiment of the invention, the "image.kim" file is an existing physical file, which triggers the execution of a program. Step ST3 corresponds to the search for the references of the file of the original image stored in the volume 71 of the storage unit 7. More precisely, this search is carried out in two stages. In the embodiment where it is the index in the request which is interpreted by the program, the search is carried out from the name of the image contained in the request. A database, present on storage volume 72, then returns the unique number of the original image which then gives access to the file from the original image. Alternatively, when the "image.kim" file is an existing physical file, the execution and interpretation of this file, which contains the unique number referencing the desired image, will make it possible, via the data contained in the database, access that image. From this data, in step ST4, all the data relating to the image file which will be necessary during the operation of adapting the display of the original image to the display characteristics are extracted. from the terminal. This data includes in particular the physical storage location of the image file, such as for example a directory and / or a storage volume name, the name of the file containing the image, its dimensions as well as the display options. by default or defined by an operator for the image and for each type of terminal.

Then, in step ST5, the type of user terminal is detected. This detection step is carried out on the basis of information transmitted with the request by the browser of the terminal. Each type of terminal uses a specific browser. It is therefore possible to determine from the information transmitted by the browser during the request whether the user wishes to receive his image on a web terminal, a personal digital assistant, a mobile telephone or the like.

However, all the data relating to the terminal which must be taken into account for the calculation of an image suitable for displaying it cannot always be obtained solely from the information provided by the browser. The information which is always supplied with the request is the signature of the browser which may contain only a few characters corresponding to a reference of the terminal model or more complete information containing for example version numbers of the browser software.

On the other hand, there is also most of the time information on the types of files accepted by the browser. Some browsers only provide this information, others go further by providing for example the dimensions and / or the number of colors of their screen. However, this information is not always relevant. For example, the information field is sometimes present, but the string is empty.

It is therefore preferable to have on the volume 72 a database which includes for each model of terminal all the characteristics useful to know about its display capacities. This database is then used to supplement or correlate the display information transmitted by the browser. This database is enriched and updated with information retrieved from manufacturers or others.

The information referenced in the database corresponds in particular to the different types of browsers listed accompanied by all the relevant information known to each of them. For browsers used with web terminals, you can reference the name and brand of the browser, its signature and the types of image supported. For browsers on personal digital assistants in addition to this information, one can find data on the different models of PDA supporting a given browser as well as their different resolutions, etc. For mobile phones, one can also find information on the ratio screen. Thus, for example, the pixels are not always square and if we want a circle on the original image not to appear as an ellipse on the display device of the terminal, we must take this into account. On the other hand, information on the memory limitations of the mobile or the network is sometimes necessary. For example, some mobiles do not accept to transfer images larger than 1.2 kilobytes. It is therefore necessary to refer to this information to limit the dimensions of the images accordingly. In addition, this information stored at the center 20 will be used to provide a suitable image in the event that a request is made from a terminal model not yet listed in the database but which belongs to a family of already known products.

In other words, the comparison with the information contained in the database makes it possible to determine the terminal in question or the type to which it belongs if it is partially or not referenced.

Thus, thanks to the database of the present invention, the information useful for calculating an image adapted to the type and display characteristics of the terminal is obtained centrally at the center 20. This represents an important advantage of the invention since no software other than the standard browser of the terminal is required. Consequently, the invention does not imply any modification at the level of the terminal, which makes it possible to send images regardless of the device model used. Steps ST3 and ST4 can be carried out either before or after step ST5, or at the same time if parallel processing is provided in the system.

Step ST6 is a step of triggering the operation of adapting the image according to the type of terminal. If the terminal detected is a mobile telephone, the method according to the invention will continue in a step ST7 where the characteristics specific to the mobile telephone model are loaded into the processing means of the center 20. From the information transmitted by the browser, we can know the type and model of the terminal, and, directly or by calling on the information contained in the database, the size of its screen, its standard display format as well as all types of images it can handle.

At this stage, the processing means of the center 20 have not only data relating to the original image sought which were extracted in step ST4 but also all the characteristics of the terminal which are necessary for the adaptation operation. of the image original in terminal display format. Firstly, it is sought in step ST70 if an earlier request from a terminal having the same characteristics and relating to the same image has not already been made. If this is the case, and if, on the one hand, the file is still present and, on the other hand, the image options for the target terminal have not been modified since, we recover, at step ST70 ′, in the “cache” volume 73, the file corresponding to the adapted image and we go directly to step ST73, otherwise, a step ST71 for calculating the new parameters of the image is performed. In this step, the format, dimensions, orientation and color (s) of the image are determined in particular from the original image, depending on the target terminal and the display options. The display options can be defined or modified by an operator of the center 30 as will be explained below. If there are no display options set by an operator, the program plans to transmit the image with default display options depending on the type of terminal. In the embodiment considered here, the default display options correspond to an image in medium resolution JPEG format for a web terminal, to a 100% image of the screen with automatic rotation depending on the orientation of the image. screen for a personal digital assistant and a 100% image of the screen with automatic rotation according to the orientation of the screen and a rendering optimized for a mobile phone.

The program can also possibly modify the compression or the dimensions of the image according to the traffic linked to the number of simultaneous requests or to the quality of the network (bandwidth), as well as according to the type of network (in particular for mobile terminals ), in order to be able to satisfy all requests with an optimal response time and as good an image quality as possible. Once all the parameters for adapting the image to the display of the terminal are determined, a "cache" volume 73 is generated in step ST72, a temporary file from the original image which is modified according to these parameters. This temporary file is then put into the form of a binary file to which information on the display format which we want to apply to the image in steps ST73 and ST74 is associated, this in order to constitute a response to the initial request. The binary file of the adapted image as well as the format information are then transmitted to the user's terminal in a step ST75. As soon as the terminal has received all of this data, the request is finished and it displays the image requested by the user on its screen according to the steps STIO and ST11. The image transmitted by the server 5 is therefore received with a format suited to the size, colors or tints and to the definition of the terminal screen, as well as possibly to the temporary or permanent characteristics of the network.

In reality, the process which has just been described in detail step by step, takes place almost in real time. Thus, as soon as the user has sent his request, he receives and almost instantly displays the document with his images. The sequence of steps ST1 to ST11 of the method according to the invention is transparent to the user, who does not perceive any latency time in obtaining a document or an image. In the event that an error occurs during the process, and as far as possible (eg network available), an image indicating the impossibility of satisfying the request will be transmitted to the terminal in place of the image requested. This image is selected from a library of predefined images, adapted beforehand to the main types of terminals.

The steps ST7 to ST75 which have been described correspond to the operation of adapting an original image to the format and the display characteristics of a model of mobile telephone. If the user is equipped with a personal digital assistant or a web terminal such as a personal computer, the adaptation operation of the original image is done through steps ST8 to ST85 for the personal digital assistant and ST9 to ST95 for the web terminal. Steps ST8 to ST85 or ST9 to ST95 are implemented in the same way as steps ST7 to ST75 described above for a mobile phone. The difference lies in the display characteristics which are taken into account for the adaptation operation according to the type of terminal. For example, in the case of a mobile phone or personal digital assistant, the image will, by default, be displayed in the direction that corresponds to normal use of the device. Nevertheless, in the case for example of portrait images which are taller than wide, one may wish to modify the orientation of the image such as for example by making it make a quarter turn so that it occupies the most space possible on the screen. In this case, it may be necessary to know the orientation of the screen to display the image in a direction allowing better readability of the image on a mobile phone or personal digital assistant while for a web terminal this characteristic is not relevant.

In FIGS. 2A and 2B, the steps of the operation of adapting the original image are illustrated for a mobile telephone, a personal digital assistant or a web terminal. However, as mentioned at the beginning of this description, those skilled in the art can easily envisage implementing the invention for any other type of terminal which includes means for receiving and displaying digital images.

FIGS. 3A and 3B represent steps of the method according to the invention which essentially correspond to the operation of determining or modifying the options for displaying the image as a function of the type of terminal considered which is carried out by an operator of the data center. content provider 30 by means of the control and processing device 6 which can be a PC type computer or a workstation connected to a computer. In FIG. 3A, in a step ST20 prior to these operations, the operator selects the original image which he wishes to view, and which he will have downloaded to the center 20 before. This selection can be made from a mosaic of images which is displayed on the screen of the device 6 and which is scrolled to consult all of the stored images. Once selected, the image is displayed (step ST21) on the screen of the device 6 preferably with a medium resolution so as not to unnecessarily slow down the display and the calculations which will be applied to the image. Indeed, this level of resolution is generally sufficient to view the modifications made to the image before the update. The operator is then in a phase ST22 which allows him either to view the previous or next image displayed in full screen, to carry out one or more treatments on the displayed image or else to define display options respectively in steps ST23, ST24 or ST25. The steps performed to perform, according to a particular embodiment of the invention, processing on the original image will be described later in relation to FIG. 4.

To continue the operation of defining the display options, the operator must select in a step ST26 the type of terminal to which the display options will apply. In the example considered here, the operator has the choice between a terminal of the personal digital assistant type, web terminal or mobile telephone. When the operator has chosen a type of terminal, such as for example a mobile telephone, he is then in a step ST29 which consists in generating and displaying on the screen of the device 6 an interface for managing the display options for the terminal considered.

FIGS. 5A, 5B and 5C show examples of display option interfaces 100, 110 and 120 respectively for a terminal of the mobile telephone type, web terminal of the personal computer type and personal digital assistant available to the operator of the center 30 . Thus, steps ST25 and following in FIG. 3 can be carried out by the operator from these interfaces. As illustrated in FIG. 5A for a terminal of the mobile telephone type, the administrator has a screen window in which a view 101 of the image on the type of terminal selected is displayed as well as the display options 102 available depending on the type of terminal. In the example considered, the operator has selected a mobile telephone as the type of terminal so that the interface 100 for managing the display options presents a view 101 of the original image which corresponds to the display of the picture on a mobile phone screen. This is achieved during step ST29 of FIG. 3 where the view 101 is put in the form of a temporary file. The operator then chooses in step ST291 the display option which he wishes to apply to the image, or else to modify, in relation to the type of terminal considered. The options available for a mobile phone can consist of modifying the image size parameters, automatically optimizing the rendering of the image or else determining a format for the image file as shown in steps ST292 to ST294. Once the option has been defined or modified, it is updated in a database saved on volume 72 of storage unit 7. This database groups, for each image, all the options display specific to all types of registered terminals. These options are extracted and applied (steps ST4 and ST71, ST81, ST91) to the image file transmitted to the user for each request depending on the type of terminal detected and the image considered.

The display options are at the image level, but we can decide to apply the same "profile" to a group of images, which would define the same behavior for all the images. If the operator decides to apply the same personal digital assistant profile to all the images classified under the same heading for example, they will all have the same options for viewing on a personal digital assistant.

As in FIGS. 2A and 2B, the operation for modifying the display options has been described with an example of a terminal of the mobile telephone type. It will nevertheless be possible to deduce from FIGS. 3A and 3B the almost identical implementation for a terminal of the web terminal or personal digital assistant type by means of the interfaces 110 or 120 respectively illustrated in FIGS. 5B and 5C. As for the image adaptation operation illustrated in FIG. 2A and 2B, the only differences relate to display options 112 (web terminal) and 122 (ANP) which are available on certain types of terminal and not on others (compression rate, automatic rendering optimization, etc.).

According to a particular embodiment of the invention, the operation of processing an original image will now be described. FIG. 4 shows the steps which take place during such processing when the operator has selected the image processing in step ST22 of FIG. 3. In step ST231, a temporary file is created which, at this point stage, corresponds to a copy of the original image. This file is a working file which allows the operator to apply transformations to the image without the risk of overwriting the file of the original image which is stored in static memory in volume 71. The temporary file corresponds to preferably copying the original image with a medium resolution sufficient to visualize the effect of the transformations. Step ST232 corresponds to the display of a processing interface which may have the form of the example of interface 130 represented in FIG. 6. The interface 130 mainly comprises a view 131 of the selected image as well as a plurality of graphic tools 132.

At this time of processing, view 131, displayed in low resolution, corresponds either to the original image as it was stored in volume 71 of the storage unit 7, or to the latest version recorded from it. During step ST233, the operator can choose between saving the modified image and applying processing to the image. In the example considered here, the operator therefore chooses, in step ST234, to apply processing to the image. The types of processing that can be applied to an image concern all the graphic transformations and filtering that can be done with an image in digital form. By way of example and as illustrated in FIG. 4 (steps ST235 to ST238) and 6, the treatments can consist of cropping, rotations, symmetries, adjustments of hue or colorimetry of the image. When a processing is carried out by the operator, the result on the image is displayed in view 131. The operator can then decide to apply other processing or to complete the image modification operation. In the latter case, in step ST233, it chooses to save the image thus modified. This backup can be done either by overwriting the old file of the original image with the new image modified in a step ST239, or by saving the latter in a new original image file with a name different from the base file to allow its recognition. during a user request in step ST240.

To increase the level of security in the system, temporary image files can be transmitted in encrypted form. In this case, the servers sending the data must include at least software and / or hardware encryption means.

Consequently, the present invention proposes a technical solution which makes it possible to carry out the transmission of digital images on any type of terminal and in any type of display format from a single original image. This solution therefore represents an important economic advantage since it does not require increasing the storage capacity currently required for the storage of a single image. The solution proposed by the present invention also has the advantage of being scalable because it allows to take into account all the new terminals marketed.

The present invention has been described in relation to a center for broadcasting still images. However, the invention also applies to the storage and dissemination of animated images such as video sequences. In this case, the video sequences will be transformed and stored in a file according to a standard for storing moving images of the "MPEG" (Group of Experts in Moving Images) type, for example.

Claims

1. A method of broadcasting digital images to allow a user, who has a terminal (2; 3; 4) comprising at least one display device, to receive and display the digital images, said digital images being stored in an image distribution center (20) accessible by the user via an at least partially public network, characterized in that it comprises the following steps: a) sending of a request on an image by the terminal of the user at the image distribution center, b) extracting data relating to the image identified in the request, c) querying a database comprising the terminal display information, d) detecting the type and display characteristics of the user's terminal, e) calculation of the new image data as a function of the data extracted from the image as well as the type and display characteristics of the detected terminal, f) generation of u n temporary image file from the new calculated data, and g) sending the generated file to the user terminal for viewing.

2. Method according to claim 1, characterized in that step e) further comprises a preliminary step of searching for and recovering a corresponding temporary file, said file having been generated during a similar previous request originating from a terminal with the same characteristics.

3. Method according to claim 1 or 2, characterized in that it further comprises a step of determining the display options according to the type of terminal.

4. Method according to claim 3, characterized in that the display options are determined for each image or for a group of images according to the type of terminal.

5. Method according to claim 3 or 4, characterized in that said display options are stored in a database of the image distribution center.

6. Method according to any one of claims 1 to 5, characterized in that in step g), said display file is associated with display format information according to the display options and the terminal of the user.

7. Method according to any one of claims 1 to 6, characterized in that it further comprises an image processing step.

8. Method according to claim 7, characterized in that the image processing step comprises geometrical and colorimetric transformations of the image.

9. Method according to any one of claims 1 to 8, characterized in that the user request is in the form of a universal address and in that there is associated with the name of the image in the request an index which automatically triggers said steps b) to g).

10. Method according to any one of claims 1 to 8, characterized in that the user request is in the form of a universal address corresponding to a file stored in the image distribution center (20), said file comprising instructions for triggering said steps b) to g).

11. Method according to any one of claims 1 to 10, characterized in that the digital images are still images.

12. Method according to any one of claims 1 to 10, characterized in that the digital images are video sequences.

13. Method according to any one of claims 1 to 12, characterized in that in steps a) and g) the data are transmitted in encrypted form.

14. Method according to any one of claims 1 to 13, characterized in that the terminal is a mobile telephone (2), a personal digital assistant (3), a web terminal (4) or a television set comprising means of access to the network.

15. Method according to any one of claims 1 to 14, characterized in that said network is the Internet network.

16. Broadcasting system for sending digital images to an at least partially public network to a terminal (2; 3; 4) comprising at least one display device, said system comprising a center (20) equipped with a server ( 5) in connection (13) with a storage unit (7) in which at least the digital images are stored, characterized in that said center (20) further comprises means to define the type and display characteristics of the terminal means for calculating, from the stored image, a new image adapted to the type and display characteristics of the terminal and means for generating a temporary file of the new picture.

17. The system as claimed in claim 16, characterized in that the storage unit (7) comprises a first volume (71) for storing the original images and a second volume (72) for storing a database of the characteristics of the terminals.

18. The system as claimed in claim 17, characterized in that, in said first volume (71), the images are stored in the form of a file and in that, in said second volume (72), additional data of options of display associated with one or more images are stored in the form of a database.

19. The system of claim 17 or 18, characterized in that the storage unit (7) further comprises a third storage volume (73) intended to temporarily store the generated image files.

20. System according to any one of claims 16 to 19, characterized in that it further comprises a center (30) for the distribution of electronic documents which comprises a server (8) in connection (15) with a storage unit (9) documents.

21. System according to any one of claims 16 to 20, characterized in that it further comprises a control and processing device (6) in connection (19) with the server (5) of the broadcasting center of images (20).

22. System according to claim 20, characterized in that it further comprises a control and processing device (6) in connection (19) with the server (5) of the image distribution center (20) and in link (21) with the server (8) of the electronic document distribution center (30).

23. System according to claim 21 or 22, characterized in that said control and processing device (6) comprises means (100-120) for determining display options associated with one or more images and means ( 130) of processing corresponding to geometric and colorimetric transformations of the image.

24. System according to any one of claims 16 to 23, characterized in that the terminal is a mobile telephone (2), a personal digital assistant (3), a web terminal or a television set comprising means of access to the network .

25. System according to any one of claims 16 to 24, characterized in that the server or servers include encryption and decryption means for the transmission of data.

26. System according to any one of claims 16 to 25, characterized in that the digital images are still images.

27. System according to any one of claims 16 to 25, characterized in that the digital images are video sequences.