JP2002232693A - Method and system for managing digital watermark, digital watermark embedding processor, digital watermark detection processor, recording medium with digital watermark management program recorded, recording medium with contents including electronic watermark recorded, electronic data delivery management device, and characteristic adjustment device for electronic data transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embed a digital watermark having low durability against destruction in contents to use this digital watermark for management of the contents in a digital watermark management system. SOLUTION: A plurality of kinds of watermark information A to C different in durability against destruction are embedded in contents by a digital watermark embedding processing part 24. A digital watermark management part 22 manages a plurality of kinds of embedding parameters A to C and pieces of watermark information A to C in relation to the contents. An electronic watermark detection processing part 26 is provided, which takes embedding parameters A to C managed by the management part 22 as detection parameters a to c to detect pieces of watermark information a to c embedded in the contents. A detection result discrimination part 38 is provided, which compares watermark information managed by the digital watermark management part 22 and watermark information detected by the digital watermark detection processing part 26 with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital watermark management system, a digital watermark management method, a digital watermark embedding processing device, a digital watermark detection processing device, a recording medium storing a digital watermark management program, and a content including a digital watermark. The present invention relates to a recorded recording medium, an electronic data distribution management device, and an electronic data transmission characteristic adjustment device. In particular, the present invention relates to a technique for embedding a digital watermark having low resistance to destruction in content and using the digital watermark for content management.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram for explaining a conventional digital watermarking process for image data contents. The conventional digital watermark processing includes a digital watermark embedding process as shown in FIG. 5A and a digital watermark detection process as shown in FIG.

As shown in FIG. 5A, in digital watermark embedding processing, watermark information 10 is embedded in the form of a digital watermark in original image data to be processed. The original image data is composed of image data such as a still image and a moving image frame. On the other hand, the watermark information 10 is code data such as characters. Several types of processes for embedding the watermark information 10 in the original image data are known. Here, as an example, a method of embedding the watermark information in the frequency space will be described.

According to this method, the original image data is DC
The frequency is expanded by a method such as T-transform (discrete cosine transform). The watermark information is based on the coefficient value (the coefficient value representing the magnitude of the frequency component) obtained as a result of the above-described frequency expansion.
They are superimposed with a predetermined watermark strength. The data obtained as a result of the superposition is reproduced as image data by being subjected to inverse DCT transform processing. In this way, embedded image data in which the watermark information is embedded is generated.

In the course of the above-described digital watermark embedding process, an embedding parameter 12 defining the conditions of the process is set.
Is set. The embedding parameter 12 includes key information for defining the embedding position of the watermark information in the frequency space coordinates, watermark strength for defining the strength of superimposing the watermark information on the coefficient value, and the like.

As shown in FIG. 5B, in the digital watermark detection processing, watermark information is detected from embedded image data. When detecting watermark information embedded in the frequency space, first, the embedded image data is frequency-expanded by DCT transform. Next, the watermark information is detected from the data after the frequency expansion under the same conditions as those at the time of the embedding process, that is, using the above-described embedding parameter 12 as the detection parameter 14. More specifically, the coordinate position of the watermark information in the frequency space is specified by the key information included in the detection parameter 14, and the value of the watermark information superimposed on the frequency coefficient value at that position is included in the detection parameter 14. It is detected based on the setting of the included watermark strength. In the digital watermark detection processing, the watermark information is detected from the embedded image data in this way.

[0007] In the embedded image data generated as described above, the watermark information becomes noise with respect to the original image data. However, by appropriately setting the frequency band in which the watermark information is embedded and the watermark strength, it is possible to generate an embedded image that cannot be distinguished from the original image by human visual observation.

[0008]

A digital watermark embedded in image data content is used as a basis for claiming copyright of the content. For this reason, the key information is normally kept private, making it impossible for a third party to detect or alter the digital watermark. On the other hand, it is known that a digital watermark embedded in content can be destroyed, for example, by performing the following image processing on the content.

That is, image processing for destroying a digital watermark includes γ conversion, gradation conversion, and filter processing called non-geometric conversion, and movement, rotation, and rotation called geometric conversion (affine conversion). A process such as an enlarged scale is assumed. When such image processing is performed on the embedded image data, the watermark information cannot be detected, and the digital watermark may not be used as the basis of the copyright claim.
For this reason, in recent years, the development of electronic watermark processing aiming at strengthening the resistance to the above-mentioned attacks has been promoted.

As described above, conventionally, a digital watermark has been required to have high resistance to destruction from the viewpoint of preventing unauthorized use of contents.

An object of the present invention is to provide a digital watermark management system and a management method for intentionally embedding a digital watermark having low resistance to destruction into content and detecting the state of the content based on the state of the low-resistance digital watermark. These are the first and second objects. It is a third and fourth object of the present invention to provide a digital watermark embedding processing device and a digital watermark detection processing device that can be used in the above digital watermark management system. A fifth object of the present invention is to provide a recording medium on which a digital watermark management program for realizing the above digital watermark management system on a computer is recorded. Also, the present invention
A sixth object of the present invention is to provide a recording medium on which content including a digital watermark necessary for management by the digital watermark management system is recorded. According to a seventh aspect of the present invention, there is provided an electronic data distribution management apparatus which detects a state of a content based on a state of a digital watermark having low resistance to destruction, and determines whether or not the content can be distributed based on the state. Aim. An eighth object of the present invention is to provide an apparatus for detecting the state of a content based on the state of a digital watermark having low resistance to destruction and adjusting the characteristics of transmission of electronic data based on the state. I do.

[0012]

According to the first aspect of the present invention,
An electronic watermark management system for executing a process of embedding watermark information in the form of an electronic watermark in the content of electronic data and a process of detecting the watermark information embedded in the content of the electronic data. A digital watermark embedding processing unit that embeds watermark information in content in the form of a type of digital watermark, an embedding parameter corresponding to each of the plurality of types of digital watermarks, and watermark information embedded in the content, A digital watermark managing unit that manages the digital watermarks in association with each other; and a digital watermark detection that detects watermark information embedded in the content in the form of the plurality of types of digital watermarks based on an embedding parameter managed by the digital watermark managing unit. A processing unit and the digital watermark management unit. And watermark information, characterized in that it comprises a detection result determining unit for comparing the watermark information detected by the electronic watermark detection processing unit.

According to a second aspect of the present invention, in the digital watermark management system according to the first aspect, the digital watermark embedding processing unit generates the plurality of types of digital watermarks by changing an embedding strength. And

According to a third aspect of the present invention, there is provided the first or second aspect.
3. The electronic watermark management system according to claim 1, wherein the electronic watermark embedding processing unit generates the plurality of types of electronic watermarks by changing an embedding algorithm.

According to a fourth aspect of the present invention, there is provided a digital watermark management for executing a process of embedding watermark information in the form of a digital watermark in the content of electronic data and a process of detecting the watermark information embedded in the content of the electronic data. A digital watermark embedding step of embedding watermark information in content in the form of a plurality of types of digital watermarks having different resistances to destruction; an embedding parameter corresponding to each of the plurality of types of digital watermarks; Content information management step of managing the associated watermark information with the content,
A digital watermark detection step of detecting watermark information embedded in the content in the form of the plurality of types of digital watermarks based on the embedding parameters managed in association with the content; and And a detection result determination step of comparing the watermark information with the watermark information detected by the digital watermark detection processing step.

According to a fifth aspect of the present invention, in the digital watermark management method according to the fourth aspect, the digital watermark embedding processing step includes a sub-step of generating the plurality of types of digital watermarks by changing an embedding strength. It is characterized by including.

The invention according to claim 6 is the invention according to claim 4 or 5.
In the digital watermark management method described above, the digital watermark embedding processing step includes a substep of generating the plurality of types of digital watermarks by changing an embedding algorithm.

According to a seventh aspect of the present invention, there is provided an electronic watermark embedding processing apparatus for embedding watermark information in the form of an electronic watermark in the contents of electronic data. A digital watermark embedding processing unit that embeds the content, an embedding parameter corresponding to each of the plurality of types of digital watermarks, and a watermark information embedded in the content, and a digital watermark management unit that manages the watermark information in association with the content. It is characterized by having.

An eighth aspect of the present invention is an electronic watermark detecting apparatus for detecting watermark information embedded in the contents of electronic data, wherein a plurality of types of electronic watermarks used for embedding the watermark information in the contents are provided. An embedding parameter corresponding to each, watermark information embedded in the content, a digital watermark management unit that manages the content in association with the content, based on the embedding parameters managed by the digital watermark management unit,
A digital watermark detection processing unit that detects watermark information embedded in the content in the form of the plurality of types of digital watermarks; a watermark information managed by the digital watermark management unit; And a detection result determining unit that compares the detected watermark information with the detected watermark information.

According to a ninth aspect of the present invention, there is provided a computer-readable recording medium having recorded thereon a program for managing a digital watermark embedded in the contents of electronic data, wherein a plurality of types of digital watermarks having different resistances to destruction are stored. Digital watermark embedding process for embedding watermark information in content in a form, information management for managing embedding parameters corresponding to each of the plurality of types of digital watermarks, and watermark information embedded in the content in association with the content A digital watermark detection process for detecting watermark information embedded in the content in the form of the plurality of types of digital watermarks based on the embedding parameters managed in association with the content; Watermark information managed by And characterized by recording a program for executing a detection result determining process for comparing the watermark information detected by the digital watermark detection process, to the computer.

According to a tenth aspect of the present invention, there is provided a computer-readable recording medium storing a program for embedding watermark information in the form of an electronic watermark in the contents of electronic data, wherein a plurality of types of electronic media having different resistances to destruction are provided. A digital watermark embedding process for embedding watermark information in content in the form of a watermark, embedding parameters corresponding to each of the plurality of types of digital watermarks, and watermark information embedded in the content are managed in association with the content. A program for causing a computer to execute the digital watermark management processing is recorded.

According to an eleventh aspect of the present invention, there is provided a computer-readable recording medium storing a program for detecting watermark information embedded in electronic data content, wherein the program is used for embedding watermark information in the content. An embedding parameter corresponding to each of the plurality of types of digital watermarks, and a watermark information embedded in the content, and a digital watermark management process of managing the content in association with the content, and managed by the digital watermark management unit. A digital watermark detection process for detecting watermark information embedded in the content in the form of the plurality of types of digital watermarks based on embedded parameters, the watermark information managed by the digital watermark management unit, A detection method for comparing with the watermark information detected by the watermark detection processing unit. Result determination process, characterized in that the recorded program to be executed by a computer.

According to a twelfth aspect of the present invention, there is provided a computer-readable recording medium, wherein a plurality of types of data corresponding to the contents of the electronic data are embedded in the contents so as to have different resistance to tampering. And data corresponding to the digital watermark.

According to a thirteenth aspect of the present invention, there is provided an apparatus for managing distribution of a content in which a digital watermark is embedded,
A watermark detection unit that detects watermark information embedded in content in the form of a digital watermark, a loss determination unit that determines whether the watermark information has a loss, and a watermark detection unit that determines that the watermark information has a loss. And a distribution prohibition unit for prohibiting the distribution of the content.

According to a fourteenth aspect of the present invention, in the electronic data distribution management device according to the thirteenth aspect, a plurality of types of electronic watermarks having different resistances to destruction are embedded in the content. Is characterized in that it is determined whether or not the watermark information corresponding to the digital watermark with the lowest tolerance has a loss.

According to a fifteenth aspect of the present invention, there is provided an apparatus for adjusting a transmission characteristic for transmitting electronic data content, wherein the encoder encodes the content with an embedded digital watermark into data transmittable on a network. A decoder that decodes the data transmitted via the network, a digital watermark detection unit that detects watermark information embedded in the form of the digital watermark in the content decoded by the decoder, A rate control unit that controls a coding rate of the encoder based on a missing state of the watermark information detected by the digital watermark detection unit.

According to a sixteenth aspect of the present invention, in the electronic data distribution management device according to the fifteenth aspect, a plurality of types of digital watermarks having different resistances to destruction are embedded in the content, and Is characterized in that the encoding rate is controlled such that no loss occurs in watermark information corresponding to a digital watermark having the lowest tolerance.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. Elements common to the drawings are denoted by the same reference numerals, and redundant description will be omitted.

Embodiment 1 FIG. 1 is a block diagram for explaining an outline of a digital watermark management system 20 according to the first embodiment of the present invention. The digital watermark management system 20 according to the present embodiment includes a digital watermark management unit 22, a digital watermark embedding processing unit 24, and a digital watermark detection processing unit 26. These components 22, 24, 26 may all be implemented on one computer,
It may be realized in a distributed manner on a plurality of computers connected via a network.

(Structure and Function of Digital Watermark Management Unit 22) The digital watermark management unit 22 mainly embeds a digital watermark in content and also detects content management information necessary for detecting the digital watermark embedded in the content. Is managed.

FIG. 2 shows an example of content management information managed by the digital watermark management unit 22. As shown in FIG. 2, the content management information includes content information 27, watermark information 28, an embedding parameter 30, and a detection parameter 32. The content information 27 is information indicating the content of the content. For example, the product name, file name, or classification (such as music content or video content) of the content corresponds to the information. Watermark information 28
Is information embedded in the content in the form of a digital watermark, and corresponds to, for example, the serial number or manufacturer of the content.

The embedding parameter 30 is information corresponding to a condition for embedding watermark information in content.
The embedding parameter 30 includes an algorithm for embedding the watermark information, key information for specifying the embedding position of the watermark information, and a watermark strength for specifying the strength of embedding the watermark information. The detection parameter 32 is information necessary for detecting watermark information from the content, and the content is the same as the content of the embedding parameter 30.

As shown in FIG. 1, the digital watermark management unit 22
Includes an embedding management unit 34, a detection management unit 36, and a detection result determination unit 38. Embedding management unit 34
Has a function of providing the watermark information 28 and the embedding parameter 30 to the digital watermark embedding processing unit 24. That is, when the target (content) of the watermark embedding process is specified, the embedding management unit 34 determines the watermark information 28 and the embedding parameter 30 based on the content information 27 of the target, and embeds them in the digital watermark embedding processing unit 24. To provide.

In the present embodiment, the embedding management unit 34
Sends a plurality of types of watermark information 28 and an embedded parameter 3
0 can be provided. FIG. 1 illustrates a case where the embedding management unit 34 provides three types of watermark information A to C and three types of embedding parameters A to C.

The three types of embedding parameters A to C are determined so that digital watermarks embedded according to the respective parameters show different resistance to destruction.
More specifically, among the information provided to the digital watermark embedding processing unit 24 as the embedding parameters A to C, the algorithm that specifies the method of embedding the digital watermark and the watermark strength that specifies the strength of the digital watermark are: Are determined so that the destruction resistance of the embedded digital watermark differs in three stages.

Algorithms for embedding a digital watermark include, for example, Nakamura, Ogawa, and Takashima, “Digital Watermarking System in Frequency Domain for Protecting Copyright of Digital Images”,
Algorithms disclosed in SCSI'97-26A (Reference 1) and Nakamura, Ogawa, Tomioka, and Takashima, "A Technique for Improving Parallel Translation / Cuting Resistance in Digital Watermarking", SCSI'99 (Reference 2) are known. I have. The algorithm of Reference 1 is faster than the algorithm of Reference 2, but the algorithm of Reference 2 is superior to the algorithm of Reference 1 in terms of fracture resistance.

Furthermore, the destruction resistance of a digital watermark can generally be improved by increasing the watermark strength regardless of the algorithm used for embedding. In the present embodiment, the three types of embedding parameters A to C provided by the embedding management unit 34 are designed so that a plurality of types of algorithms as described above and the watermark strength are appropriately combined to make the digital watermark destruction resistance different. Is set.

The detection management unit 36 is a digital watermark detection processing unit 2
6 has a function of providing the detection parameter 32. The detection management unit 36 grasps the correspondence between the individual contents and the watermark information embedded therein, and the correspondence between the individual contents and the embedding parameters used when embedding the watermark information therein. ing.
When the target (content) of the watermark detection processing is specified, the detection management unit 36 determines the embedded watermark information 28 and the embedding parameter 30 used for the embedding based on the content information 27 of the target. And The specified embedding parameters 30 (algorithm, key information, and watermark strength) are provided to the digital watermark detection processing unit 26 as the detection parameters 32.

As described above, in this embodiment, three types of watermark information A to C are used for one content, and three types of embedding parameters A to C for realizing different destruction resistances.
Embedded with In response, the detection management unit 36
Three types of watermark information a to c for one content
And three types of detection parameters a to c are provided.

The detection result judging section 38 is a section for judging whether or not the watermark information embedded in the content is destroyed, based on the detection result supplied from the digital watermark detection processing section 26. In the present embodiment, the digital watermark detection processing unit 26 detects, from one content, detection results a to c corresponding to three types of watermark information having different destruction resistances, as described later. The detection result determination unit 38 compares the detection results a to c with the watermark information a to c specified by the detection management unit 36 to determine whether the watermark information embedded in the content has been destroyed. Is determined.

(Structure and Function of Digital Watermark Embedding Processing Unit 24) The digital watermark embedding processing unit 24 has a function of performing different types of watermark embedding processing on a single original image data a plurality of times. FIG. 1 shows that the digital watermark embedding processing unit 2 corresponds to three types of embedding parameters 30 provided from the digital watermark management unit 22.
4 illustrates a case where three types of watermark embedding processes A to C are executed.

That is, in FIG. 1, the digital watermark embedding processing section 24 performs processing on the original image data to be processed.
First, a watermark embedding process A40 is performed. According to the watermark embedding process A40, the watermark information A is embedded in the original image data under the conditions specified by the embedding parameter A. As a result, embedded image data A is generated.

Next, the digital watermark embedding processing section 24 performs a watermark embedding process B42 on the embedded image data A. According to the watermark embedding process B42, the watermark information B is embedded in the embedded image data A under the conditions specified by the embedding parameter B, and as a result, embedded image data A + B is generated.

The digital watermark embedding section 24 further performs a watermark embedding process C44 on the embedded image data A + B. According to the watermark embedding process C44, the watermark information C is embedded in the embedded image data A + B under the conditions specified by the embedding parameter C. As a result, embedded image data A + B + C is generated.

As described above, the embedding parameters A to C
Are set so that the digital watermark embedded according to them shows different destruction resistance. Therefore, according to the digital watermark embedding processing unit 24, three types of watermark information A
~ C can be embedded in a single content in the form of a digital watermark showing different destruction resistance to various attacks.

(Configuration and Function of Digital Watermark Detection Processing Unit 26) The digital watermark detection processing unit 26 performs different types of watermark detection processing on a single embedded image data processed by the digital watermark embedding processing unit 24. It has a function to perform multiple times. FIG. 1 illustrates a case where the digital watermark embedding unit 26 executes three types of watermark detection processes a to c in response to the digital watermark embedding unit 24 embedding three types of digital watermarks in the content. ing.

That is, in FIG. 1, the digital watermark detection processing unit 26 first performs a watermark detection process a46 on embedded image data a + b + c in which three types of digital watermarks are embedded. According to the watermark detection process a46, the digital watermark is generated under the condition specified by the detection parameter a, that is, with the detection parameter a corresponding to the embedding parameter A used for embedding the watermark information A in the content to be processed. Is detected. Therefore, according to the above processing, the detection result a corresponding to the watermark information A can be obtained from the embedded image data. The detection result a thus obtained is supplied to the detection result determination unit 38 as described above.

Next, the digital watermark detection processing section 26 performs the watermark detection processing b on the embedded image data a + b + c.
48 is performed. According to the watermark detection process b48, the digital watermark is generated under the condition specified by the detection parameter b, that is, with the detection parameter b corresponding to the embedding parameter B used to embed the watermark information B in the content to be processed. Is detected. Therefore, according to the above-described processing, a detection result b corresponding to the watermark information B can be obtained from the embedded image data. The detection process b thus obtained is supplied to the detection result determination unit 38 as described above.

Next, the digital watermark detection processing section 26 performs the watermark detection processing c on the embedded image data a + b + c.
50 is applied. According to the watermark detection process c50, the digital watermark is generated under the condition specified by the detection parameter c, that is, with the detection parameter c corresponding to the embedding parameter C used to embed the watermark information C in the content to be processed. Is detected. Therefore, according to the above processing, a detection result c corresponding to the watermark information C can be obtained from the embedded image data. The detection process c thus obtained is supplied to the detection result determination unit 38 as described above.

In this embodiment, the detection result judging section 38
Compares the detection results a to c supplied from the digital watermark detection processing unit 26 with the watermark information a to c specified by the detection management unit 36, and determines whether the three types of watermark information have been destroyed. Determine whether or not. Among these pieces of watermark information, a digital watermark with low destruction resistance is easily destroyed by any attack in the market. On the other hand, a digital watermark with high destruction resistance can avoid destruction even if it is attacked in the market.

Therefore, in the present embodiment, a digital watermark with low destruction resistance is used as a flag (hereinafter, referred to as an “attacked flag”) indicating whether or not the content has been attacked in the market for the purpose of destruction of the watermark. Can be used. The electronic flag with high destruction resistance can be used as a means for integrating information with high importance, for example, information such as a serial number and a manufacturer required as a basis for a copyright claim into content. .

As described above, according to the system of the present embodiment, the digital watermark can be made to function as an attack flag while functioning for the purpose of achieving the original purpose (claiming copyright and the like). This attack flag is used as a basis for guaranteeing the identity of the content (it is a genuine product)
Alternatively, it can be used as a ground that the identity has been destroyed in the market, and also as a ground to refuse compensation for loss caused by the use of an illegally copied product.
Thus, according to the system of the present embodiment, the function of the digital watermark can be enhanced.

By the way, in the above description of the first embodiment, a case is described in which three types of digital watermarks having different destruction resistances are used, but the types of digital watermarks are not limited to three types. That is, the types of digital watermarks having different destruction resistances may be two or four or more.

In the first embodiment, both the technique of changing the embedding algorithm and the technique of changing the watermark strength are used together in order to make the destruction resistance of the digital watermark different, but these techniques are not necessarily used together. do not have to. That is, the destruction resistance of the digital watermark may be changed only by changing the embedding algorithm.
Alternatively, the algorithms may be different only by changing the watermark strength by unifying the algorithms.

In the first embodiment described above, three types of watermark information A to C are embedded in a single content, but the watermark information may be the same information.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows a block diagram of an electronic data distribution management device according to the second embodiment of the present invention. In FIG. 3, arrows indicated by solid lines are paths through which the content is transmitted. In FIG. 3, arrows indicated by broken lines indicate the flow of control signals.

The distribution management device of the present embodiment is a device that determines whether electronic data can be distributed based on the state of a low-resistance digital watermark embedded in content. Hereinafter, a case will be described in which the distribution management device of the present embodiment handles embedded contents generated by the method of the first embodiment, that is, contents having a plurality of types of digital watermarks having different durability.

The distribution management device of the present embodiment has an input interface (I / F) 52 for taking in data of embedded contents. A digital watermark detection unit 54 is provided downstream of the input I / F 52. The digital watermark detection unit 54 detects the watermark information embedded in the content by the same method as the digital watermark detection processing unit 26 according to the first embodiment. An encoder 56 that encodes the content data into a format that can be transmitted to a network is provided further downstream of the digital watermark detection unit 54.

The distribution management device of the present embodiment further includes a destruction judging unit 58 and a distribution prohibiting unit 60. The destruction determination unit 58 is a digital watermark management unit 2 according to the first embodiment.
In a manner similar to 2, it is determined whether the digital watermark detected by the digital watermark detection unit 54 has been destroyed. The distribution prohibition unit 60 is a block that prohibits the distribution of the content from the encoder 56 to the network when the destruction determination unit 58 determines that the digital watermark has been destroyed.

Among the digital watermarks embedded in the content, a digital watermark with low resistance is easily destroyed when any external factor that causes an abnormality in the content occurs. Therefore, a digital watermark having low durability can be used as a control flag for determining whether or not a defective portion has occurred in the content. According to the present embodiment, when such an electronic flag is broken,
The distribution prohibition unit 60 automatically prohibits the distribution of the content. Therefore, according to the distribution management device of the present embodiment, it is possible to effectively prevent the outflow of the content including the defective part.

In the second embodiment described above, the digital watermark detection unit 54 detects the watermark information in the same manner as in the first embodiment. In other words, all the digital watermarks included in the content are detected. It is going to be detected. However, in realizing the distribution management device of the present embodiment, it is not necessary for the digital watermark detection unit 54 to detect all digital watermarks. That is, in the present embodiment,
The digital watermark detection unit 54 only needs to be able to detect only the one with the lowest tolerance among the digital watermarks included in the content.

In the second embodiment described above, the case where the distribution management device processes content having a plurality of types of digital watermarks having different resistances is described. If such content is to be processed, it is possible to realize both the function of retaining the basis of the copyright claim in the content and the function of preventing leakage of defective content. However, in order to realize the distribution management device of the present embodiment, it is not always necessary to include a highly durable digital watermark in the content, and only a low durable digital watermark that is easily destroyed by an external factor is included in the content. It only has to be included.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a block diagram of a characteristic adjustment device for electronic data transmission according to the third embodiment of the present invention. In FIG. 4, arrows indicated by solid lines are paths through which the content is transmitted. In FIG. 4, arrows indicated by broken lines indicate the flow of control signals.

The characteristic adjusting apparatus of this embodiment uses a low-resistance digital watermark embedded in the content as a quality judgment flag of the content transmitted through the network, and based on the state of the flag, determines the transmission path. This is a device for adjusting the coding rate. Hereinafter, a case will be described in which the characteristic adjustment device of the present embodiment adjusts the coding rate using embedded content generated by the method of Embodiment 1, that is, content having a plurality of types of digital watermarks having different durability. .

The characteristic adjustment device of the present embodiment has an input I / F 62 for taking in data of an embedded content. At the subsequent stage of the input I / F 62, there is provided an encoder 64 for transmitting content data to the network by the MPEG2 / MPEG4 distribution function. Further, the characteristic adjustment device of the present embodiment includes a decoder 66 that receives and decodes data transmitted through a network,
And output I / F6 for extracting content data
8 is provided.

The characteristic adjusting device of this embodiment further includes a digital watermark detecting section 70 and a rate controlling section 72. The digital watermark detection unit 70 uses the same method as the digital watermark management unit 22 in the first embodiment, and the digital watermark detection unit 54 uses the same method as that in the first embodiment. Is detected, and it is further determined whether or not the weak watermark has been destroyed.
The rate control unit 72 controls the encoder 6 while the digital watermark detection unit 70 detects the destruction of the weak watermark.
4 is continuously adjusted in the increasing direction.

In the present embodiment, a digital watermark having low durability is embedded in a content so as to be destroyed when the image quality of the content transmitted via the network is lower than a predetermined level. Therefore, the digital watermark with low durability can be used as a control flag for determining whether or not the image quality of the content has reached a predetermined level.

In the present embodiment, when such an electronic flag is destroyed, the coding rate is corrected in the increasing direction so that the image quality after transmission is improved. For this reason, according to the characteristic adjustment device of the present embodiment, the encoding rate of the transmission path can be easily set to the minimum rate necessary to realize a predetermined level of image quality.

In the third embodiment, the digital watermark detection unit 70 detects the watermark information by the same method as in the first embodiment. It is not necessary to detect all the digital watermarks included in. That is, in the present embodiment, the digital watermark detection unit 70 only needs to detect the digital watermark contained in the content that has the lowest resistance.

In the third embodiment described above, a case is described in which the characteristic adjustment device processes the content generated by the method of the first embodiment. However, in realizing the characteristic adjustment device of the present embodiment, it is not always necessary to include a highly durable digital watermark in the content, and the content includes only a durable digital watermark that is easily destroyed. It should just be.

[0071]

As described above, according to the present invention, the state of the content itself can be easily determined based on the state of the low-resistance digital watermark that is intentionally embedded in the content. Therefore, according to the present invention, it is possible to easily verify the presence or absence of an attack on the content for the purpose of destroying the digital watermark, assure the identity of the content, and the like, and further facilitate the quality management of the content distributed via the network. can do.

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital watermark management system according to a first embodiment of the present invention.

FIG. 2 is a list of content management information used for content management in the system of the first embodiment.

FIG. 3 is a block diagram of an electronic data distribution management device according to a second embodiment of the present invention.

FIG. 4 is a block diagram of a characteristic adjustment device for electronic data transmission according to a third embodiment of the present invention.

FIG. 5 is a block diagram for explaining a conventional digital watermarking process.

[Explanation of symbols]

 Reference Signs List 20 digital watermark management system 22 digital watermark management unit 24 digital watermark embedding processing unit 26 digital watermark detection processing unit 34 embedding management unit 36 detection management unit 38 detection result determination unit 54; 70 digital watermark detection unit 58 destruction determination unit 60 distribution prohibition unit 72 Rate control unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomio Kishimoto 1-12-1 Dogenzaka, Shibuya-ku, Tokyo NTT Electronics Corporation (72) Inventor Tsuneo Okubo 1-12-1 Dogenzaka, Shibuya-ku, Tokyo NTT Electronics Corporation (72) Inventor Hiroshi Ogawa 2-3-1 Otemachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Takao Nakamura 2-3-1 Otemachi, Chiyoda-ku, Tokyo No. Within Nippon Telegraph and Telephone Corporation (72) Inventor Noboru Sonehara 2-3-1 Otemachi, Chiyoda-ku, Tokyo F-Term within Nippon Telegraph and Telephone Corporation 5B057 CA08 CA12 CA16 CB08 CB12 CB16 CC01 CE08 CH08 5C063 AC01 AC10 DA07 DA13 DB09 5C076 AA14 BA06 5J104 AA12 AA14 (54) [Title of Invention] Digital watermark management system System, digital watermark management method, digital watermark embedding processing device, digital watermark detection processing device, recording medium recording digital watermark management program, recording medium recording content including digital watermark, electronic data distribution management device, and electronic device A device for adjusting the characteristics of data transmission.

Claims (16)

[Claims] 1. An electronic watermark management system for executing a process of embedding watermark information in the form of an electronic watermark in the content of electronic data and a process of detecting the watermark information embedded in the content of the electronic data. A digital watermark embedding processing unit that embeds watermark information in content in the form of a plurality of types of digital watermarks having different resistances to the content, an embedding parameter corresponding to each of the plurality of types of digital watermarks, and watermark information embedded in the content. A digital watermark management unit that manages the content in association with the content, and, based on embedding parameters managed by the digital watermark management unit, watermark information embedded in the content in the form of the plurality of types of digital watermarks. A digital watermark detection processing unit for detecting, and the digital watermark management And the watermark information being managed in,
A digital watermark management system, comprising: a detection result determining unit that compares the digital watermark information with the watermark information detected by the digital watermark detection processing unit. 2. The digital watermark management system according to claim 1, wherein the digital watermark embedding processing unit generates the plurality of types of digital watermarks by changing an embedding strength. 3. The digital watermark management system according to claim 1, wherein the digital watermark embedding processing unit generates the plurality of types of digital watermarks by changing an embedding algorithm. 4. A digital watermark management method for executing a process of embedding watermark information in the form of an electronic watermark in the content of electronic data and a process of detecting the watermark information embedded in the content of the electronic data, the method comprising: A digital watermark embedding step of embedding watermark information in the content in the form of a plurality of types of digital watermarks having different resistances to watermarks; an embedding parameter corresponding to each of the plurality of types of digital watermarks; and a watermark information embedded in the content. Detecting a watermark information embedded in the content in the form of the plurality of types of digital watermarks based on the embedding parameter managed in association with the content. Digital watermark detection step Said watermark information in association with the serial contents are managed, the electronic watermark management method characterized in that it comprises a and a detection result determining step of comparing the watermark information detected by the electronic watermark detection processing step. 5. The digital watermark management method according to claim 4, wherein the digital watermark embedding processing step includes a substep of generating the plurality of types of digital watermarks by changing an embedding strength. 6. The digital watermark management method according to claim 4, wherein the digital watermark embedding processing step includes a sub-step of generating the plurality of types of digital watermarks by changing an embedding algorithm. 7. An electronic watermark embedding processing device for embedding watermark information in the form of electronic watermark in the contents of electronic data, wherein the watermark information is embedded in the content in the form of a plurality of types of electronic watermarks having different resistance to destruction. A processing unit, and an embedding parameter corresponding to each of the plurality of types of electronic watermarks, and an electronic watermark management unit that manages watermark information embedded in the content in association with the content. Digital watermark embedding processing unit. 8. An electronic watermark detection device for detecting watermark information embedded in content of electronic data, comprising: an embedding parameter corresponding to each of a plurality of types of electronic watermarks used for embedding watermark information in the content. An electronic watermark management unit that manages watermark information embedded in the content in association with the content, based on the embedding parameters managed by the electronic watermark management unit, A digital watermark detection processing unit that detects watermark information embedded in the form of a digital watermark, and watermark information managed by the digital watermark management unit.
A digital watermark detection device, comprising: a detection result determination unit that compares the watermark information detected by the digital watermark detection processing unit with the watermark information. 9. A computer-readable recording medium on which a program for managing a digital watermark embedded in the content of electronic data is recorded, wherein the watermark information is stored in a form of a plurality of types of digital watermarks having different resistances to destruction. An electronic watermark embedding process, an embedding parameter corresponding to each of the plurality of types of electronic watermarks, and an information management process of managing watermark information embedded in the content in association with the content. A digital watermark detection process for detecting watermark information embedded in the content in the form of the plurality of types of digital watermarks based on the embedding parameters managed in association with the watermark; and a watermark managed in association with the content. Information and the digital watermark detection Recording medium characterized by recording a program for executing a detection result determining process for comparing the watermark information detected, to a computer in the process. 10. A computer-readable recording medium in which a program for embedding watermark information in the form of digital watermark in the contents of electronic data is recorded, wherein the watermark information has a plurality of types of digital watermarks having different resistances to destruction. A digital watermark embedding process for embedding the content in the content, an embedding parameter corresponding to each of the plurality of types of digital watermarks, and a watermark information embedded in the content, and a digital watermark management process for managing the watermark information in association with the content. A program for causing a computer to execute the program. 11. A computer-readable recording medium on which a program for detecting watermark information embedded in content of electronic data is recorded, wherein a plurality of types of electronic media used to embed watermark information in the content are provided. An embedding parameter corresponding to each of the watermarks, a watermark information embedded in the content, a digital watermark management process for managing the content in association with the content, and an embedding parameter managed by the digital watermark management unit. An electronic watermark detection process for detecting watermark information embedded in the content in the form of the plurality of types of electronic watermarks; and watermark information managed by the electronic watermark management unit.
A recording medium characterized by recording a program for causing a computer to execute a detection result determination process of comparing the watermark information detected by the digital watermark detection processing unit with the watermark information. 12. A method for recording data corresponding to electronic data content and data corresponding to a plurality of types of electronic watermarks embedded in the content so as to have different resistance to tampering. Computer readable recording medium. 13. An apparatus for managing distribution of a content in which a digital watermark is embedded, comprising: a watermark detection unit that detects watermark information embedded in the content in the form of a digital watermark; An electronic data distribution management device, comprising: a loss determining unit that determines whether or not the watermark information has been lost; and a distribution prohibition unit that prohibits distribution of the content when the watermark information has loss. 14. A plurality of types of digital watermarks having different resistances to destruction are embedded in the content, and the loss determining unit determines whether or not the watermark information corresponding to the least resistant digital watermark has a loss. 14. The electronic data distribution management device according to claim 13, wherein the determination is made. 15. An apparatus for adjusting characteristics of transmission for transmitting contents of electronic data, comprising: an encoder for encoding contents in which a digital watermark is embedded into data that can be transmitted over a network; A decoder for decoding the data transmitted by the electronic watermark detection unit; a digital watermark detection unit for detecting watermark information embedded in the digital watermark format in the content decoded by the decoder; and a digital watermark detection unit. And a rate control unit that controls a coding rate of the encoder based on the detected missing state of the watermark information. 16. A plurality of types of digital watermarks having different resistances to destruction are embedded in the content, and the rate control unit prevents loss of watermark information corresponding to the digital watermark with the lowest resistance. The electronic data distribution management device according to claim 15, wherein the encoding rate is controlled.