JP2014175757A - Digital watermark processing system for generating digital watermark by coupling divided elements, server, program and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital watermark processing system capable of maintaining quality in contents and preventing expansion of a file size while implementing efficient digital watermark processing.SOLUTION: The digital watermark processing system comprises: division content generation means for generating M kinds of division contents by embedding M pieces of digital watermark data items in the contents; content encoding processing means for applying encoding processing to each of the division contents in such a manner that the processed content is formed from an encoding unit (GOP) with a fixed time length or the fixed number of frames; content dividing means for dividing each of M kinds of encoded division contents into divided elements each formed from one or more GOPs; and digital watermark content generation means for selecting one of the M kinds of divided elements so as to form a digital watermark pattern corresponding to a provision object, and generating digital watermark contents by coupling a series of selected divided elements.

Description

  The present invention relates to a digital watermark processing technique for embedding specific information such as copyright information in content such as moving images and music.

  Needless to say, when a content distribution service such as video or music is implemented, the copyright of the creator or seller of the content should be protected. As a means for protecting the copyright, there is an encryption technique that encrypts the content data to be distributed so that only authorized users who possess the decryption key can reproduce it. However, in this case, the possibility that the user redistributes the decrypted content on the network (secondary distribution) cannot be excluded. On the other hand, there is a digital watermark processing technique as a copyright protection means that can prevent unauthorized use such as secondary distribution.

  When embedding a digital watermark in content for the purpose of copyright protection, there are two roles: (a) copyright claim and (b) user identification. In particular, for the latter, if information about the user of the distribution destination can be embedded in the distribution content using digital watermark, even if this content is secondary distributed, the user who performed the secondary distribution should be identified. Can do.

  Here, the process of embedding the digital watermark related to user information in the content needs to be performed not on the client side that reproduces the content but on the distribution server side that distributes the content. This is because if digital watermark processing is performed on the client side, it is necessary to force the client user to execute an application for embedding, and if that processing is avoided, content without the digital watermark embedded can be easily Will be obtained.

  However, especially for video content with a huge amount of information, content with different digital watermarks embedded for each user is prepared in advance on the distribution server side, or content with different digital watermarks embedded every time a user requests a content. It is practically difficult to generate a message on the distribution server side. That is, the former requires a data storage area proportional to the number of users. In the latter case, the processing capacity limit on the distribution server side becomes a bottleneck.

  Actually, for example, when digital watermark processing independent of the format of moving image content is performed, it is necessary to embed the digital watermark in the uncompressed state of the content file. For this reason, the amount of data processing when embedding a digital watermark becomes enormous, and further re-encoding processing after embedding takes considerable time. As a result, it becomes difficult for the user who has requested the content to perform the digital watermark processing within a time period that does not cause inconvenience.

  In order to solve such a problem of embedding digital watermark for each user, for example, in Patent Document 1, a plurality of digital watermark recording blocks in which digital watermark data is embedded in a block as content division data are combined for each distribution processing unit. A technique for setting a different digital watermark data sequence is disclosed.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for preparing content in which m types of digital watermarks are embedded in one content element in advance by dividing the content into predetermined time lengths. In this case, the content element in which the digital watermark is embedded is combined based on the user ID to generate the content, and the content is distributed, whereby the user ID can be specified from the combination pattern of the digital watermark.

JP 2012-39437 A JP 2007-207051 A

  However, in the conventional techniques such as Patent Documents 1 and 2 described above, problems remain in the quality and file size of the content embedded with the electronic watermark.

  For example, in the technique disclosed in Patent Document 1, the content dividing method when handling moving image content is not clear. Also, the combination of divided contents is not defined, and it is assumed that a playlist is used for reproducing the contents. Thus, it is difficult for the distributed user to enjoy the sense of ownership if the content is still divided.

  On the other hand, in the technique of Patent Document 2, a method for dividing moving image content is clarified. Here, first, the moving image content is divided by a certain length of time, and then a digital watermark is embedded in the divided content elements, and then these content elements are combined based on a combination associated with user information.

  In general, when a content distribution company receives content from a content holder, the received content file has already been encoded. Here, in order to divide the encoded moving image content without degradation, it is necessary to divide at a GOP (Group of Picture) boundary. However, the number of frames in a GOP (Group of Picture) in the encoded moving image content is usually not constant. For this reason, in order to divide a moving image content in which the number of frames in the GOP is not constant with a certain length of time according to the technique of Patent Document 2, a re-encoding process is required to fix the number of frames in the GOP. . This leads to degradation of image quality in the moving image content.

  Furthermore, according to the technique of Patent Document 2, when the divided moving image contents are individually encoded and combined, the encoder causes a difference in degree, but the bit rate is often increased for the image quality. As a result, the file size increases.

  Therefore, the present invention is an electronic watermarking process capable of maintaining the quality of content embedded with a digital watermark and suppressing an increase in file size while performing an efficient digital watermarking process in response to a content request for each user, for example. It is an object to provide a system and method.

According to the present invention, there is provided a digital watermark processing system capable of embedding a digital watermark in content,
Digital watermark pattern management means for storing a digital watermark pattern in association with each content provision target in advance;
Dividing content generating means for generating M types of dividing content by embedding each of M digital watermark data different from each other for each division unit of content;
Content encoding processing means for performing an encoding process so that the processed content is configured with a predetermined time length or a predetermined number of frames for each generated content for division;
Content dividing means for dividing each of the M types of content for division that has been encoded into division elements composed of at least one encoding unit;
For each of a series of division elements constituting the divided content encoded so as to form a digital watermark pattern associated with the content provision target, there are M types depending on the difference of the embedded digital watermark data. There is provided a digital watermark processing system including digital watermark content generation means for selecting one of the division elements and combining the selected series of division elements to generate digital watermark content.

In addition, as an embodiment capable of performing digital watermark error correction in the digital watermark processing system, the digital watermark processing system includes:
A digital watermark detection means for acquiring a content length portion corresponding to one digital watermark pattern in the content acquired via the network and detecting a series of digital watermark data embedded in the portion;
In this content length portion, when there is a length portion of the division element that failed to detect the digital watermark data, until the digital watermark data in the length portion of the division element that failed to be detected can be complemented, A content length portion corresponding to one digital watermark pattern following the content length portion is further extracted, and a series of digital watermark data embedded in the extracted portion is detected, and one digital watermark pattern is detected. Digital watermark data correction means for obtaining a corresponding series of digital watermark data;
The detection pattern information, which is a series of digital watermark data corresponding to one acquired digital watermark pattern, is compared with a digital watermark pattern stored in advance, and a digital watermark pattern corresponding to the detection pattern information is determined. It is also preferable to further include a provision target specifying unit that specifies a provision target associated with the determined digital watermark pattern as a target for providing the content.

  In the embodiment relating to the error correction of the digital watermark, the digital watermark detection means divides the acquired content length portion by at least one coding unit having the length of the division element, and from each divided portion thus divided. It is also preferable to extract the embedded digital watermark data.

Furthermore, in the digital watermark processing system according to the present invention,
The digital watermark pattern is expressed by a series of N pattern units, and each of the pattern units having a plurality of types is associated with one of M digital watermark data different from each other in advance,
The digital watermark content generation means, for each of N units in a series of division elements constituting the encoded content for division, sets M types of division elements as n (1 ≦ n ≦ N) -th division elements. Among them, the division element in which the digital watermark data previously associated with the nth pattern unit among the N pattern units is selected is selected, and the repetition of N units in the selected series of division elements is combined. It is also preferable to generate digital watermark content.

  Further, in the digital watermark processing system according to the present invention, the content encoding processing means performs encoding processing so that the processed content is configured with a GOP (Group of Picture) having a certain number of frames as an encoding unit. It is also preferable.

Furthermore, as one embodiment of the digital watermark processing system according to the present invention, the digital watermark processing system includes:
A digital watermark pattern generation server having digital watermark pattern management means;
Content combining / distribution server having division content generation means, content encoding processing means, content division means, digital watermark content generation means, and content transmission means for transmitting the generated digital watermark content to a provision target via a network It is also preferable that

Furthermore, as an embodiment of the digital watermark processing system according to the present invention having a digital watermark error correction function, the digital watermark processing system includes:
A digital watermark detection server having a digital watermark detection means and a digital watermark data correction means;
A digital watermark pattern generation server having a digital watermark pattern management means and a provision target specifying means;
Content combining / distribution server having division content generation means, content encoding processing means, content division means, digital watermark content generation means, and content transmission means for transmitting the generated digital watermark content to a provision target via a network It is also preferable that

According to the present invention, there is further provided a digital watermark processing server capable of embedding a digital watermark in content,
Digital watermark pattern management means for storing a digital watermark pattern in association with each content provision target in advance;
Dividing content generating means for generating M types of dividing content by embedding each of M digital watermark data different from each other for each division unit of content;
Content encoding processing means for performing an encoding process so that the processed content is configured with a predetermined time length or a predetermined number of frames for each generated content for division;
Content dividing means for dividing each of the M types of content for division that has been encoded into division elements composed of at least one encoding unit;
For each of a series of division elements constituting the divided content encoded so as to form a digital watermark pattern associated with the content provision target, there are M types depending on the difference of the embedded digital watermark data. There is provided a digital watermark processing server including a digital watermark content generation unit that selects one of the divided elements and combines the selected series of divided elements to generate a digital watermark content.

According to the present invention, there is further provided a digital watermark processing program capable of embedding a digital watermark in content,
Digital watermark pattern management means for storing a digital watermark pattern in association with each content provision target in advance;
Dividing content generating means for generating M types of dividing content by embedding each of M digital watermark data different from each other for each division unit of content;
Content encoding processing means for performing an encoding process so that the processed content is configured with a predetermined time length or a predetermined number of frames for each generated content for division;
Content dividing means for dividing each of the M types of content for division that has been encoded into division elements composed of at least one encoding unit;
For each of a series of division elements constituting the divided content encoded so as to form a digital watermark pattern associated with the content provision target, there are M types depending on the difference of the embedded digital watermark data. There is provided a digital watermark processing program for selecting one of the division elements and combining the selected series of division elements to generate a digital watermark content to function as a digital watermark content generation unit.

According to the present invention, there is further provided a digital watermark processing method capable of embedding a digital watermark in content,
A first step of storing an electronic watermark pattern in association with each content provision target in advance;
A second step of generating M types of content for division by embedding each of M digital watermark data different from each other for each content division unit;
A third step of performing an encoding process for each generated content for division so that the processed content is configured by a coding unit having a certain time length or a certain number of frames;
A fourth step of dividing each of the M types of division content that has been encoded into division elements each including at least one encoding unit;
For each of a series of division elements constituting the divided content encoded so as to form a digital watermark pattern associated with the content provision target, there are M types depending on the difference of the embedded digital watermark data. A watermark processing method is provided that includes selecting a one of the split elements and combining the selected series of split elements to generate a watermark content.

  According to the digital watermark processing system and method of the present invention, for example, in response to a content request for each user, efficient digital watermark processing is performed, while maintaining the quality of the content embedded with the digital watermark and increasing the file size. Can be suppressed.

It is the schematic which shows one Embodiment of the digital watermark processing system by this invention. It is a functional block diagram in one Embodiment about the server which comprises the digital watermark processing system by this invention. It is a sequence diagram which shows one Embodiment of the digital watermark processing method by this invention. It is the schematic which shows one Embodiment of the flow which produces | generates a digital watermark content from the original content in the digital watermark processing method by this invention. It is the schematic which shows one Embodiment of the flow which specifies a provision object (primary delivery destination) user from the content acquired on the network in the digital watermark processing method by this invention.

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

[Digital watermark processing system]
FIG. 1 is a schematic diagram showing an embodiment of a digital watermark processing system according to the present invention.

  Referring to FIG. 1, the digital watermark processing system of this embodiment includes a content combination / distribution server 1, a digital watermark pattern generation server 2, and a digital watermark detection server 3 that are connected to each other via a network such as the Internet 6. And. The servers 1 to 3 can be connected to a plurality of terminals 5 through a network such as the Internet 6 or an access network. Further, the content combination / distribution server 1 is communicably connected to the content holder 4 via a network such as the Internet 6.

  The content combining / distribution server 1 receives “original content” that is moving image content from the content holder 4. The creator or seller of the “original content” has a copyright on the “original content”, and unauthorized use such as secondary distribution must be prevented. For this reason, a digital watermark process for embedding a digital watermark uniquely associated with the provision target user (terminal 5) of the distribution (primary distribution) destination is performed on the “original content”.

When the content combining / distribution server 1 receives this “original content”,
<Watermark embedding> Each of M digital watermark data different from each other is embedded in “original content” to generate M types of content for division,
<Encoding> Encoding processing is performed on each division content so that the processed content is configured by a coding unit (for example, GOP) having a certain time length or a certain number of frames,
<Division> Each of the M types of division contents subjected to the encoding process is divided into division elements each including at least one coding unit and stored.

Furthermore, the content combining / distribution server 1 responds to a content distribution request from the provision target user (terminal 5) to the digital watermark pattern generation server 2,
<Combination: Digital watermark pattern formation> Among the M types of division elements so as to form a “digital watermark pattern” (received from the digital watermark pattern generation server 2) associated with the provision target user (terminal 5). Combine a series of segmentation elements while selecting one to generate “watermark content”, then
<Content distribution> “Digital watermark content” is transmitted to the provision target user (terminal 5) via the network.

  In general, it is very difficult to embed a digital watermark at a high speed in a form that immediately responds to a user's content request for a large volume of moving image content. On the other hand, the content combining / distribution server 1 generates a plurality of types of moving image content in which different types of digital watermark data are embedded and performs encoding (compression) processing. What is divided (dividing elements) by a predetermined number of frames (eg, GOP) is prepared in advance. Next, in response to a content distribution request from the provision target user (terminal 5), a combination of different division elements is generated for each user, and the series of division elements are combined and distributed as digital watermark content.

  As a result, from the point in time when the “digital watermark pattern” corresponding to the user information such as the user ID is acquired, the user information is embedded as a digital watermark simply by combining and combining the division elements generated in advance. Distribution content can be generated. In other words, efficient and high-speed digital watermark processing according to the user information of the distribution destination can be performed.

  What is important here is to embed digital watermark data in the processing stage before dividing the moving image content. In the conventional technique of Patent Document 2, for example, the moving image content is first divided, and then the digital watermark data is embedded in each divided element. In this case, at least when the moving image content is received from the content holder, the encoding process is performed once, and before dividing the moving image content, the GOP length (number of frames) needs to be constant, so that it is once more. After performing and dividing, the digital watermark data is embedded, and then the encoding process is performed once more. In other words, the prior art requires at least three encoding processes in total, and there is a concern that image quality may deteriorate.

  On the other hand, in the present embodiment (content combination / distribution server 1), the moving image content is divided after the digital watermark data is embedded. As a result, the encoding process may be performed twice, once when the moving image content is received and once after embedding the digital watermark data. Here, the encoding process after embedding the digital watermark data is performed so that the processed content is composed of a coding unit (for example, GOP) having a certain time length or a certain number of frames. This re-encoding process becomes unnecessary. As described above, in the present embodiment, the number of times of the encoding process can be surely reduced as compared with the conventional case, so that higher image quality can be maintained.

  In addition, in the conventional technique in which the divided video contents are individually encoded and then combined, there is a difference depending on the encoder, but the bit rate is often high for the image quality, resulting in the file size Will increase. On the other hand, in the present embodiment, since the encoding process and the dividing process are performed after embedding the digital watermark data, the file size at the time of combining the contents can be further reduced. It becomes feasible. Furthermore, since the moving image content to be distributed is combined into one file, the authorized user can also enjoy the content ownership.

In FIG. 1, the digital watermark detection server 3 further acquires “digital watermark content” that may have been secondarily distributed via the network.
<Digital Watermark Data Detection> Obtains a content length portion corresponding to one digital watermark pattern in the acquired “digital watermark content”, detects a series of digital watermark data embedded in this portion, ,
<Digital Watermark Data Correction> When there is a length portion of a division element in which detection of digital watermark data has failed in the acquired content length portion, one digital watermark pattern following the content length portion is included. A corresponding content length portion is further extracted, a series of digital watermark data embedded in this portion is detected, and the digital watermark data in the length portion of the division element that has failed to be detected is complemented. A series of watermark data corresponding to minutes,
<Detection pattern information transmission> “Detection pattern information” which is a series of digital watermark data corresponding to one acquired digital watermark pattern is transmitted to the digital watermark pattern generation server 2.

  In general, a digital watermark embedded in a moving image content may be difficult to detect by being secondarily distributed after being subjected to recompression processing, reduction processing, or format conversion by an unauthorized user, for example. On the other hand, in this embodiment, moving image content in which a digital watermark pattern composed of a combination of division elements composed of at least one coding unit is repeatedly embedded is handled. As a result, even when the digital watermark pattern cannot be detected in a part of the moving image content, error correction of the digital watermark can be performed by complementing the detected digital watermark data. Thus, the present embodiment is a powerful deterrent means against secondary content distribution by unauthorized users.

Furthermore, the digital watermark pattern generation server 2
<Digital Watermark Pattern Generation> A digital watermark pattern is generated for each content provision target user (terminal 5) and stored in association with each other. further,
<Identification of user to be provided> The received “detection pattern information” is compared with a digital watermark pattern stored in advance to determine a “digital watermark pattern” corresponding to this “detection pattern information”. The provision target user associated with the “digital watermark pattern” is specified as the target for providing the content.

The digital watermark pattern generation server 2
<Digital watermark pattern transmission> “Digital watermark pattern” associated with the provision target user (terminal 5) registered and stored in advance when the “content request” is received from the provision target user (terminal 5). And is sent to the content combination / distribution server 1.

  FIG. 2 is a functional configuration diagram of an embodiment of the servers 1 to 3 constituting the digital watermark processing system according to the present invention.

[Content Merge / Distribution Server 1]
In FIG. 2, the digital watermark processing system includes a content combination / distribution server 1, a digital watermark pattern generation server 2, and a digital watermark detection server 3. Among these, the content combination / distribution server 1 includes a transmission / reception interface 100, an original content storage unit 101, a content division element storage unit 102, and a processor memory. Here, the processor memory realizes its function by executing a program.

  The processor memory has a division content generation unit 110, a content encoding processing unit 111, a content division unit 112, and a digital watermark content generation unit 113 as functional components.

  The transmission / reception interface 100 receives the original content which is the moving image content from the content holder 4 in advance and outputs it to the original content storage unit 101. In addition, the digital watermark pattern associated with the provision target user is received from the digital watermark pattern generation server 2 and output to the digital watermark content generation unit 113. Further, the generated electronic watermark content is transmitted to the provision target user (terminal 5) via the network.

  The original content storage unit 101 includes, for example, an HDD (Hard Disk Drive), an optical disk device, or a semiconductor memory, and stores the original content acquired via the transmission / reception interface 100. Further, the content division element accumulation unit 102 accumulates the division elements generated by dividing the content in the content division unit 112.

  The division content generation unit 110 holds M (≧ 2) pieces of digital watermark data different from each other in advance. Next, the original content to be processed is input from the original content storage unit 101, and each of these M pieces of digital watermark data is embedded for each division unit (for example, frame) of the original content to generate M types of content for division. To do.

  The content encoding processing unit 111 is configured such that, for each division content input from the division content generation unit 110, the processed content is configured by a coding unit (eg, GOP) having a certain time length or a certain number of frames. Next, the encoding process is performed.

  The content division unit 112 receives the M types of division content encoded from the content encoding processing unit 111, and divides each of the M types of division content into at least one coding unit (for example, GOP). Split into elements. Next, the generated divided elements (which are M types depending on the difference in the embedded digital watermark data) are output to the content divided element storage unit 102 and stored in advance.

When the digital watermark content generation unit 113 inputs a digital watermark pattern associated with a content provision target, the digital watermark content generation unit 113 forms the digital watermark pattern.
(A) For each of a series of division elements constituting the encoded division content, select one of M types of division elements input from the content division element storage unit 102;
(B) The digital watermark content is generated by combining the selected series of divided elements.

[Digital watermark pattern generation server 2]
The digital watermark pattern generation server 2 includes a transmission / reception interface 200, a user information storage unit 201, and a processor memory. Here, the processor memory includes a digital watermark pattern management unit 210 and a content provision target specifying unit 211 as functional configuration units.

  The transmission / reception interface 200 receives detection pattern information that is a series of digital watermark data corresponding to one digital watermark pattern from the digital watermark detection server 3, and outputs the detection pattern information to the content provision target specifying unit 211. In addition, among the generated digital watermark patterns, the digital watermark pattern associated with the provision target user (terminal 5) who has made a content distribution request is transmitted to the content combination / distribution server 1.

  The user information accumulation unit 201 accumulates a digital watermark pattern in association with each user (user ID) registered as a subscription to the content distribution service, for example. Also, the digital watermark pattern management unit 210 receives a registration request from the user (terminal 5), generates a digital watermark pattern for each registered user, stores it in the user information storage unit 201, and manages it as user information To do. The generation of the digital watermark pattern may be performed when a content distribution request is received from the user (terminal 5) as in step S313 in FIG. 3 to be described later.

  The content provision target specifying unit 211 collates the acquired detection pattern information with a digital watermark pattern stored in advance in the user information storage unit 201, determines a digital watermark pattern corresponding to the detection pattern information, and determines The provision target user (user ID) associated with the digital watermark pattern thus identified is specified as the target for providing the content.

[Digital watermark detection server 3]
The digital watermark detection server 3 includes a transmission / reception interface 300, an acquired content storage unit 301, and a processor memory. Here, the processor memory includes a digital watermark detection unit 310 and a digital watermark data correction unit 311 as functional components.

  The transmission / reception interface 300 transmits a content request for acquiring the secondary distribution content, and acquires the distributed content.

  The acquired content storage unit 301 stores the acquired content. Further, the digital watermark detection unit 310 acquires a content length portion corresponding to one digital watermark pattern in the content input from the acquired content storage unit 301, and obtains a series of digital watermark data embedded in this portion. To detect. The digital watermark detection unit 310 further outputs the detected series of digital watermark data to the digital watermark data correction unit 311.

The digital watermark data correction unit 311 determines the digital watermark data in the length part of the division element that failed to be detected when the length part of the division element that failed to detect the digital watermark data exists in the content length part. Until it can be complemented
(A) The content length portion corresponding to one digital watermark pattern following the content length portion is further extracted, and then
(B) The digital watermark detection unit 310 detects a series of digital watermark data embedded in the extracted portion, and finally completes a series of digital watermark data corresponding to one digital watermark pattern. ,get.

  Of course, the present invention is not limited to the embodiment described above. As an embodiment of the present invention, a digital watermark processing server (apparatus) having the functions of the content combination / distribution server 1, the digital watermark pattern generation server 2, and the digital watermark detection server 3 can be used. A server (apparatus) having the functions of the content combining / distribution server 1 and the digital watermark pattern generation server 2 may be used.

[Digital watermark processing method]
FIG. 3 is a sequence diagram showing an embodiment of a digital watermark processing method according to the present invention.

(S300) The content combination / distribution server 1 acquires in advance the original content that may be distributed from the content holder 4.
(S301) The content combination / distribution server 1 embeds each of M digital watermark data different from each other in the original content to generate M types of content for division.

(S302) The content combination / distribution server 1 performs an encoding process on each division content so that the processed content is configured with a coding unit (for example, GOP) having a certain time length or a certain number of frames. To do.
(S303) The content combination / distribution server 1 divides each of the M types of divided content that has undergone the encoding process into divided elements composed of at least one coding unit, and stores them in the content divided element storage unit .

(S310) The digital watermark pattern generation server 2 registers a user (user ID) who has applied for subscription to the content distribution service.
(S311) A registered user (terminal 5) accesses the digital watermark pattern generation server 2, and user authentication is performed between the two based on the registration information in step S310.
(S312) The digital watermark pattern generation server 2 receives a content distribution request from a registered user (terminal 5).

(S313) The digital watermark pattern generation server 2 generates a digital watermark pattern associated with the user ID of the user (terminal 5) that is the content provision target.
(S314) The content combination / distribution server 1 receives the digital watermark pattern generated from the digital watermark pattern generation server 2.

(S315) The content combination / distribution server 1 selects one of the M types of division elements and combines the series of division elements so as to form the received (designated) digital watermark pattern. Generate watermark content.
(S316) The content combination / distribution server 1 distributes the generated digital watermark content to the provision target user (terminal 5). Here, the digital watermark content may be distributed after being subjected to a predetermined encryption process, or may be distributed in plain text.
(S317) The terminal 5 reproduces the distributed digital watermark content. When the digital watermark content is distributed in plain text, it can be played back by a general media player.

(S320) The digital watermark detection server 3 transmits a content distribution request to a plurality of distribution servers that are performing the video distribution, for example, regularly or at the time of investigation in order to acquire the secondary distributed video content. To do.
(S321) The digital watermark detection server 3 acquires moving image content from an external distribution server.
(S322) The digital watermark detection server 3 acquires a content length portion corresponding to one digital watermark pattern in the acquired moving image content, and detects a series of digital watermark data embedded in this portion.

(S323) The digital watermark detection server 3 includes a digital watermark pattern following the content length portion when there is a length portion of the divided element that has failed to detect the digital watermark data in the acquired content length portion. A part of the content length corresponding to one is further extracted. Next, a series of digital watermark data embedded in this portion is detected, and digital watermark error correction is performed to complement the digital watermark data in the length portion of the division element that failed to be detected.
(S324) The digital watermark detection server 3 transmits detection pattern information, which is a series of digital watermark data corresponding to one acquired digital watermark pattern, to the digital watermark pattern generation server 2.

(S325) The digital watermark pattern generation server 2 collates the received detection pattern information with a digital watermark pattern stored in advance, and determines a digital watermark pattern corresponding to this detection pattern information.
(S326) The digital watermark pattern generation server 2 specifies a provision target user associated with the determined digital watermark pattern as a target to which content is secondarily distributed.

[Generate watermark content]
FIG. 4 is a schematic diagram showing an embodiment of a flow for generating digital watermark content from original content in the digital watermark processing method according to the present invention.

  According to FIG. 4, first, for each frame of the original content, M (≧ 2) pieces of digital watermark data (M = 4 in FIG. 4) ([00], [01], [[ 10] and [11]) are embedded. Subsequently, the original content in which the first digital watermark data [00] is embedded, the original content in which the second digital watermark data [00] is embedded, and so on, M (= 4) types The content for division is generated.

  For example, when the moving image content transmitted from the content holder 4 has been subjected to compression coding processing such as MPEG (Moving Picture Experts Group) 2, first, the moving image content is first decoded and uncompressed. It is preferable to use content.

  Next, each of the generated M (= 4) types of content for division is subjected to an encoding process. At this time, the encoding process is, for example, a compression encoding process such as MPEG2, and the processed content is configured to be configured with an encoding unit having a certain time length or a certain number of frames, for example, a GOP having a certain number of frames. Is done.

  Next, each of the M types of division content that has been encoded is divided into division elements each including at least one GOP. In general, in a compression encoding process such as MPEG2, inter-frame prediction is performed in each picture, and division in a form that cuts off the prediction causes deterioration in image quality. On the other hand, since frame prediction does not reach between GOPs, it is possible to avoid such image quality deterioration by setting the boundary of GOP as a division break.

  Usually, one GOP has 15 to 300 frames. Here, one division element may be one GOP or a plurality of GOPs. For example, a series of 10 GOPs can be used as one division element. In any case, the division element is generated by dividing at the GOP boundary. Moreover, it is preferable that a division | segmentation element is set to fixed time length or fixed frame number. This facilitates detection when the digital watermark data is detected later.

  Thereafter, when the digital watermark pattern associated with the user to be provided is acquired, a series of division elements << 1 >>, << 2 >>, which constitute the divided content encoded so as to form the digital watermark pattern, For each of <3>,..., One of M types of division elements is selected depending on the difference in the embedded digital watermark data.

Specifically, in FIG. 4, the digital watermark pattern is expressed by N (N = 6 in FIG. 4) pattern units,
A, B, D, C, B, D
Is written. Here, A indicates digital watermark data [00], B indicates [01], C indicates [10], and D indicates [11]. Thus, each of the pattern units having a plurality of types is associated in advance with one of M digital watermark data different from each other.

  Next, for each of N (= 6) units in a series of division elements constituting the encoded division content, M (= 4) types of divisions are used as the n (1 ≦ n ≦ N) -th division element. Among the elements, a divided element in which digital watermark data previously associated with the nth pattern unit among the N pattern units is embedded is selected.

Specifically, each dividing element is formed so as to form the digital watermark pattern (A, B, D, C, B, D).
Dividing element << 1 >> → A, Dividing element << 2 >> → B, Dividing element << 3 >> → D,
Dividing element << 4 >> → C, Dividing element << 5 >> → B, Dividing element << 6 >> → D,...
Is selected.

Here, the length of one digital watermark pattern corresponds to the length of N (= 6) division elements. Therefore, one digital watermark pattern can be formed with the division elements << 1 >> to << 6 >>. further,
Dividing element << 7 >> → A, Dividing element << 8 >> → B, Dividing element << 9 >> → D,
Dividing element << 10 >> C, Dividing element << 11 >> B, Dividing element << 12 >> D ...
As described above, patterns of A, B, D, C, B, and D are repeatedly selected in units of N divided elements (= 6).

  Finally, the selected series of segmentation elements are combined to generate digital watermark content to be distributed. In this digital watermark content, a digital watermark that can identify the user to be provided is embedded as N combinations of division elements having M types of digital watermark information. Specifically, digital watermark data is embedded so as to repeatedly form digital watermark patterns (A, B, D, C, B, D) associated with a provision target user (user ID). As a result, it is possible to perform digital watermark error correction described in detail below.

[Digital watermark error correction]
FIG. 5 is a schematic diagram showing an embodiment of a flow for specifying a provision target (primary distribution destination) user from content acquired on a network in the digital watermark processing method according to the present invention.

  According to FIG. 5, first, a content length portion corresponding to one digital watermark pattern is acquired from an arbitrary position or a predetermined position in content acquired via a network. Here, the length of one digital watermark pattern corresponds to the length of N divided elements (N = 6 in FIG. 5). Therefore, the portion of the content length to be extracted is the number of division elements N (= 6).

  Next, the acquired content length portion is divided by “at least one coding unit (GOP)” having the length of the division element. As a result, the acquired content length portion is N (= 6) divided elements.

Next, a series of digital watermark data embedded in the N (= 6) divided elements is detected. In FIG. 5, sequentially from the top,
A [00], B [01],? [? ? ], C [10], B [01],? [? ? ]
The electronic watermark data is detected. here,? [? ? ] Is the length portion of the segmentation element that failed to detect the digital watermark data. This detection failure refers to a case where the data detected at a predetermined embedding position does not match any of the digital watermark data groups that may exist. For example, recompression processing, reduction processing, or format conversion is performed by an unauthorized user. It can occur a lot in content that has been applied and secondarily distributed.

  Here, when the probability of digital watermark detection failure in each divided element is p, detection failure occurs in an average of pN divided elements out of N divided elements. In this embodiment, when there are division elements that have failed to be detected, a content length portion corresponding to N division elements following the first extracted content length portion is further extracted to detect a digital watermark. The digital watermark data corresponding to the division elements that have failed to be detected in the extracted content length portion are supplemented (corrected).

Further, in one position in the N units of the division element content, the probability of missed detection for two consecutive times becomes p ^2. Accordingly, in the moving image content from which 2N content length portions are extracted, detection failure occurs in an average of p ² · N division elements, and the detection failure probability is further suppressed. If the digital watermark data for one digital watermark pattern is still not completed (acquired), the number to be extracted is 3N.
4N is sequentially increased and complemented (corrected) until there is no error in the digital watermark.

Specifically, in FIG. 5, in order to complement the digital watermark data in the (third and sixth) length portions of the division elements that failed to be detected, error correction of the digital watermark is performed as shown below.
(A) A content length portion corresponding to one digital watermark pattern (for division elements N (= 6)) following the content length portion previously extracted is further extracted,
(B) Further detecting a series of digital watermark data embedded in the extracted content length portion,
(C) A series of digital watermark data corresponding to one digital watermark pattern is selected by selecting digital watermark data in the (third and sixth) length portions of the division elements that have failed to be detected first. Complete the watermark data.

In FIG. 5, the first N (= 6) pieces of digital watermark data A [00], B [01],? [? ? ], C [10], B [01],? [? ? ]
On the other hand, the next N (= 6) pieces of digital watermark data A [00],? [? ? ], D [11], C [10], B [01],? [? ? ]
Since these data are not completely complemented, the following digital watermark data A [00], B [01], D [11], C [10],? [? ? ], D [11]
Is finally obtained,
A [00], B [01], D [11], C [10], B [01], D [11]
Is completed.

Then
(D) Detection pattern information (A [00], B [01], D [11], C [10], B [01], D [11]), which is completed digital watermark data, is stored in advance. The digital watermark pattern (A, B, D, C, B, D) corresponding to the detected pattern information is determined by collating with the digital watermark pattern,
(E) A provision target user (a user with user ID = 003322 in FIG. 5) associated with the determined digital watermark pattern (A, B, D, C, B, D) is set as a target for providing content. Identify.

  Incidentally, when N (= 6) pieces of digital watermark data are detected 100% without failure by the content length part (for the division element N (= 6)) obtained first, these digital watermark data are detected. Can be collated with a digital watermark pattern stored in advance as detection pattern information.

  It should be noted that when the acquired (completed) series of digital watermark data (detection pattern information) is collated with a digital watermark pattern stored in advance, it is preferable that the same circle permutation matches. In this case, for example, detection pattern information of A, B, D, C, B, D is (B, D, C, B, D, A), (D, C, B, D, A) as digital watermark patterns. A, B), (C, B, D, A, B, D), (B, D, A, B, D, C), (D, A, B, D, C, B), and (A , B, D, C, B, D). However, in this case, the same digital permutation pattern as a circle permutation is associated with the same provision target user.

  In addition, it is also preferable that a specific digital watermark data (for example, A [00]) or a specific digital watermark data sequence (for example, A [00] -B [01]) is determined in advance. In this case, even if the acquired (completed) series of digital watermark data is, for example, B, D, C, B, D, A, the detection pattern information is A, B, D, C, B, D Can do. However, in this case, the digital watermark pattern associated in advance with the user to be provided is a pattern in which the specific digital watermark data (sequence) is used first, and thereafter the specific digital watermark data (sequence) is not used. Is preferred.

  Furthermore, the digital watermark patterns previously associated with the provision target user may be different from each other as a circle permutation with the specific digital watermark data (sequence) as the head. For example, when the specific digital watermark data sequence at the head is set to B [01] -D [11], B, D, C, B, D, A and B, D, A, B, D , C are the same pattern, and only one of them is adopted as the digital watermark pattern.

  Furthermore, double embedding of a digital watermark may be performed. For example, digital watermark data “E” to be used in a form of being superimposed on a digital watermark pattern formed from M (= 4) different digital watermark data such as A, B, C, and D is prepared. Next, for example, only “E” is embedded in the division element corresponding to the head portion of a series of digital watermark data such as A, B, D, C, B, and D. That is, “E” is used as a marker representing the head of the detection pattern information. At this time, for example, it is also preferable to previously form division content in which “E” is embedded in addition to each of A, B, C, and D, and to divide after the encoding process. As a result, an electronic watermark pattern (A (+ E), B, D, C, B, D) can be formed. According to the above method, in the detection pattern information, the data portion having “E” can always be regarded as the head, and therefore, unique collation with a digital watermark pattern stored in advance is possible.

  As described above in detail, according to the present invention, after a plurality of types of moving image content embedded with different types of digital watermark data are generated and encoded, a certain time length or a certain number of frames are encoded. A division element divided in units (for example, GOP) is prepared in advance. Next, in response to a content distribution request from a provision target user, a combination of different division elements is generated for each user, and the series of division elements are combined and distributed.

  As a result, it is possible to generate a distribution content in which this user information is embedded as a digital watermark simply by combining and combining previously generated division elements from the time when a content distribution request is received from the user. . That is, efficient and high-speed digital watermark processing according to user information (user ID) can be performed.

  Further, according to the present invention, the encoding process may be performed twice, once when the moving image content is received and once after embedding the digital watermark data. Thereby, for example, higher image quality can be maintained as compared with the prior art that requires at least three encoding processes such as Patent Document 2.

  In the present invention, since the encoding process and the dividing process are performed after embedding the digital watermark data, the file size at the time of content combination can be further reduced, and as a result, a high capacity and a low capacity can be realized. It becomes.

  Furthermore, in the present invention, moving image content in which a digital watermark pattern composed of a combination of generated divided elements is repeatedly embedded is handled. As a result, even when the digital watermark pattern cannot be detected in a part of the moving image content, error correction of the digital watermark can be performed by complementing the detected digital watermark data. That is, it is possible to provide a powerful deterrent means against secondary content distribution by unauthorized users.

  For the various embodiments of the present invention described above, various changes, modifications, and omissions in the technical idea and scope of the present invention can be easily made by those skilled in the art. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

DESCRIPTION OF SYMBOLS 1 Content combination | distribution server 100 Transmission / reception interface 101 Original content storage part 102 Content division | segmentation element storage part 110 Division content generation part 111 Content encoding process part 112 Content division part 113 Digital watermark content generation part 2 Digital watermark pattern generation server 200 Transmission / reception Interface 201 User information storage unit 210 Digital watermark pattern management unit 211 Content provision target specifying unit 3 Digital watermark detection server 300 Transmission / reception interface 301 Acquired content storage unit 310 Digital watermark detection unit 311 Digital watermark data correction unit 4 Content holder 5 Terminal 6 Internet

Claims (10)

A digital watermark processing system capable of embedding a digital watermark in content,
A digital watermark pattern management means for storing a digital watermark pattern in association with each content provision target in advance;
Dividing content generating means for generating M types of dividing content by embedding each of M digital watermark data different from each other for each division unit of the content;
Content encoding processing means for performing an encoding process so that the processed content is configured with a predetermined time length or a predetermined number of frames for each generated content for division;
Content dividing means for dividing each of the M types of content for division subjected to the encoding process into division elements composed of at least one encoding unit;
For each of a series of division elements constituting the divided content encoded so as to form a digital watermark pattern associated with the content provision target, there are M types depending on the difference of the embedded digital watermark data. A digital watermark processing system comprising: a digital watermark content generating unit that selects one of the divided elements to be combined and generates a digital watermark content by combining the selected series of divided elements. Digital watermark detection means for acquiring a part of the content length corresponding to one digital watermark pattern in the content acquired via the network and detecting a series of digital watermark data embedded in the part;
When there is a length portion of the division element that has failed to detect the digital watermark data in the content length portion, the digital watermark data in the length portion of the division element that has failed to be detected can be complemented Until the content length portion corresponding to one digital watermark pattern following the content length portion is further extracted, a series of digital watermark data embedded in the extracted portion is detected, and the electronic watermark pattern is detected. Digital watermark data correcting means for acquiring a series of digital watermark data corresponding to one watermark pattern;
The detected pattern information, which is a series of digital watermark data corresponding to the acquired one digital watermark pattern, is collated with the digital watermark pattern stored in advance, and the digital watermark pattern corresponding to the detected pattern information is obtained. The digital watermark processing according to claim 1, further comprising: a provision target specifying unit that determines and provides the provision target associated with the determined digital watermark pattern as a target for providing the content. system.   The digital watermark detection means divides the acquired content length portion by at least one encoding unit having the length of the division element, and extracts embedded digital watermark data from each divided portion The digital watermark processing system according to claim 2, wherein: The digital watermark pattern is expressed by a series of N pattern units, and each of the pattern units having a plurality of types is associated in advance with one of M digital watermark data different from each other,
The digital watermark content generation means uses M types of N (1 ≦ n ≦ N) division elements as N (1 ≦ n ≦ N) -th division elements for each of the N units in a series of the division elements constituting the encoded content for division. Among the divided elements, a divided element in which digital watermark data previously associated with the nth pattern unit among the N pattern units is selected is selected, and N units in the selected series of divided elements The digital watermark processing system according to claim 1, wherein the digital watermark content is generated by combining the repetitions of the above.   5. The content encoding processing unit performs encoding processing so that the processed content is configured with a GOP (Group of Picture) having a certain number of frames as an encoding unit. The electronic watermark processing system according to any one of the above. A digital watermark pattern generation server having the digital watermark pattern management means;
The division content generation means, the content encoding processing means, the content division means, the digital watermark content generation means, and a content transmission means for transmitting the generated digital watermark content to the provision target via a network The electronic watermark processing system according to claim 1, further comprising: a content combination / distribution server having the content. A digital watermark detection server comprising the digital watermark detection means and the digital watermark data correction means;
A digital watermark pattern generation server having the digital watermark pattern management means and the provision target specifying means;
The division content generation means, the content encoding processing means, the content division means, the digital watermark content generation means, and a content transmission means for transmitting the generated digital watermark content to the provision target via a network The digital watermark processing system according to claim 2, further comprising: a content combination / distribution server having the content. A digital watermark processing server capable of embedding a digital watermark in content,
A digital watermark pattern management means for storing a digital watermark pattern in association with each content provision target in advance;
Dividing content generating means for generating M types of dividing content by embedding each of M digital watermark data different from each other for each division unit of the content;
Content encoding processing means for performing an encoding process so that the processed content is configured with a predetermined time length or a predetermined number of frames for each generated content for division;
Content dividing means for dividing each of the M types of content for division subjected to the encoding process into division elements composed of at least one encoding unit;
For each of a series of division elements constituting the divided content encoded so as to form a digital watermark pattern associated with the content provision target, there are M types depending on the difference of the embedded digital watermark data. A digital watermark processing server, comprising: digital watermark content generation means for selecting one of the divided elements to be generated and combining the selected series of divided elements to generate digital watermark content. A digital watermark processing program capable of embedding a digital watermark in content,
A digital watermark pattern management means for storing a digital watermark pattern in association with each content provision target in advance;
Dividing content generating means for generating M types of dividing content by embedding each of M digital watermark data different from each other for each division unit of the content;
Content encoding processing means for performing an encoding process so that the processed content is configured with a predetermined time length or a predetermined number of frames for each generated content for division;
Content dividing means for dividing each of the M types of content for division subjected to the encoding process into division elements composed of at least one encoding unit;
For each of a series of division elements constituting the divided content encoded so as to form a digital watermark pattern associated with the content provision target, there are M types depending on the difference of the embedded digital watermark data. A digital watermark processing program that causes a computer to function as digital watermark content generation means that generates one digital watermark content by selecting one of the divided elements to be combined, and combining the selected series of divided elements. A digital watermark processing method capable of embedding a digital watermark in content,
A first step of storing a digital watermark pattern in association with each content provision target in advance;
A second step of generating M types of content for division by embedding each of M digital watermark data different from each other for each division unit of the content;
A third step of performing an encoding process for each generated content for division so that the processed content is configured by a coding unit having a certain time length or a certain number of frames;
A fourth step of dividing each of the M types of the content for division subjected to the encoding processing into division elements each including at least one encoding unit;
For each of a series of division elements constituting the divided content encoded so as to form a digital watermark pattern associated with the content provision target, there are M types depending on the difference of the embedded digital watermark data. And a fifth step of generating a digital watermark content by combining one of the divided elements to be generated and combining the selected series of divided elements.

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