JP2002152486A - Digital watermarking processing method for vector type image data and digital watermarking information control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital watermarking embedding technology into vector type image data itself. SOLUTION: One vector (P1-Q3) within original vector type image data is split into a plurality of segments (S1, S2, and S3). Each segment is split into two division vectors (DV1 and DV2, DV3 and DV4, and DV5 and DV6) at a prescribed division ratio 'm:n' or 'k:1' corresponding to 1 bit code '1' or '0' desired to be embedded there. Thus, a code of a plurality of bits is embedded as digital watermarking in the original vector (P1-Q3). Furthermore, an arrangement order of division vectors (DV1, DV2, DV3, DV4, DV5, DV6) is changed to a random arrangement order by a prescribed scramble algorithm, and further coordinate values of the start point and the end point of the division vectors (DV1, DV2, DV3, DV4, DV5, DV6) are changed to relative coordinates from the end point of the split vector just before the split vector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for protecting the copyright of vector-type image data, and more particularly to a technique for embedding and extracting a digital watermark in vector-type image data, and managing and collating the digital watermark information. About.

[0002]

2. Description of the Related Art When selling vector image data such as vector map data and CAD design data or distributing them to the Internet, vector image data is used as an effective copyright protection measure to control illegal copying and tampering. By embedding a digital watermark (= a technology that allows other information to be added to content so that it is not perceived by humans), the data on the market is copyright holder data or tampered with There is a need for a technology that can detect whether the data is data that has been transmitted.

Conventionally, a raster type (that is, a bit map type)
Regarding digital watermark technology for image data, there is a technology for embedding a digital watermark without substantially deteriorating the quality of original raster image data. However, there is no practical method as a digital watermarking technique for vector image data.

Therefore, conventionally, as a method for preventing unauthorized use or falsification of vector-type image data, vector-type image data is converted into a raster-type image data format, and a digital watermark is added to the data before distribution. For example, in a system for distributing vector-type image data on the Internet, the server-side transmits vector-type image data to a GI.
Convert to raster type image data such as F file, JPEG file or PNG file, embed a digital watermark in it,
The raster image data is delivered to the client.

However, in this conventional system, the client receives the raster image data, so every time the image is enlarged or reduced or scrolled, the client requests the server to generate the raster image data again and distributes the image again. I have to get it. Further, the client cannot individually recognize various graphic elements in the raster type image data and handle them independently. For example, in the case of a map, the client cannot select each map graphic element such as each building or each road with a mouse click or give it a unique attribute. As a result, the conventional image distribution system has extremely poor performance and operability.

[0006]

SUMMARY OF THE INVENTION Accordingly, one object of the present invention is to provide a technique for embedding a digital watermark in vector-type image data itself.

Another object of the present invention is to provide a technique for embedding an electronic watermark in vector-type image data without deteriorating the quality of the original.

Another object of the present invention is to provide a method for protecting vector-type image data from illegal copying and falsification (format conversion, enlargement / reduction, movement, rotation, partial area extraction, merging with other images, etc.). It is an object of the present invention to provide a reliable digital watermarking technique.

Still another object of the present invention is to provide a monochrome (2
It is an object of the present invention to provide a digital watermarking technique for vector-type image data, which can be applied to both a value-based image and a multi-valued gray-scale image and a color image.

Still another object of the present invention is to provide a technique for restoring reproducible vector image data of an original image from digital watermarked vector image data.

Still another object of the present invention is to enable reproduction of an original image from vector image data with a digital watermark by referring to secret information (for example, a risk rumble algorithm) that can be held only by a valid user. Another object of the present invention is to provide a technique for restoring various vector-type image data.

Still another object of the present invention is to provide a technique for extracting a digital watermark from vector image data with a digital watermark.

Still another object of the present invention is to create a digital watermark from vector image data with a digital watermark by referring to secret information (for example, rules of bit coding) that can be held only by the copyright holder. It is to provide a technique for extracting.

Still another object of the present invention is to extract a digital watermark from vector-type image data on the market when there is a suspicion of unauthorized copying or falsification of the digital-watermarked vector-type image data. It is an object of the present invention to provide a technique for enabling detection of unauthorized copying or tampering.

Still another object of the present invention is to provide a digital watermark information management system for vector-type image data.

Still another object of the present invention is to provide a digital watermark information management system for detecting unauthorized copying or falsification of digital watermarked vector image data distributed on the market.

[0017]

According to a first aspect of the present invention, there is provided a method for embedding a digital watermark in vector-type image data, the step of selecting a vector from original vector-type image data; Dividing the vector into at least two division vectors at a predetermined division ratio assigned to a code to be embedded as a watermark.

According to this method, an arbitrary code is embedded in the vector image data itself as a digital watermark. Moreover, since the divided vector does not impair the graphic information of the original vector, the quality of the image of the original vector image data is not impaired. That is, this method makes it possible to produce digital watermarked vector image data capable of completely reproducing the original image. This method can be applied to both monochrome (binary and multi-level gray scale) images and color images. In addition, since the digital watermark is embedded without damaging the graphic represented by the original vector, unauthorized copying and falsification of vector-type image data (format conversion, enlargement / reduction, movement, rotation, partial area cutout, other image With merging). If the code to be embedded is long, the long code may be divided into a plurality of subcodes, a plurality of vectors corresponding to the number of subcodes may be selected, and each subcode may be embedded in each vector.

In a preferred embodiment, a vector selected from the original vector image data is divided into a plurality of segments, and each segment is divided into at least two divided vectors. Each segment is divided at a predetermined division ratio assigned to a code to be embedded therein. In this way, a code corresponding to the division ratio is embedded in each segment as a digital watermark. By combining a plurality of codes embedded in a plurality of segments, larger embedded information can be expressed.

In a preferred embodiment, in order to improve resistance to attacks, a plurality of divided vectors in which a digital watermark is embedded are subjected to a scrambling process of a predetermined algorithm, and at least one of the divided vectors is processed. The original coordinate values of the start point and the end point of one divided vector are converted to another coordinate value.

The scrambling process can be performed, for example, by (1)
Obtaining another arrangement order from the original arrangement order of the plurality of divided vectors, (2) with respect to at least one of the divided vectors in the divided vectors, has a predetermined order relationship in the different arrangement order Another divided vector is selected, and (3) the original coordinate values of the starting point and the ending point of the at least one divided vector are converted into relative coordinate values measured from the starting point or the ending point of the another divided vector. Can do it.

A restoration method according to a second aspect of the present invention comprises:
A digital watermarked vector-type image data containing a plurality of divided vectors in which a digital watermark is embedded and subjected to scramble processing, and which can reproduce the same original image as the original vector-type image data before the scramble processing is performed. Then, secret information including vector specifying information for specifying the plurality of divided vectors and an algorithm of a risk rumble process which is an inverse operation of the scramble process is input. Then, based on the vector specifying information in the secret information, the plurality of divided vectors are specified from within the digital watermarked vector image data, and for the specified plurality of divided vectors,
A risk rumble process in the secret information is performed. As a result, the plurality of scrambled divided vectors are returned to the original state before the scramble processing, so that the reproducible vector image data of the original image is restored.

The above-mentioned secret information (algorithm of the risk rumble process, etc.) can be managed so that only a legitimate user can hold it. As a result, only a legitimate user can reproduce the original image from the digital watermarked vector image data.

A digital watermark extracting method according to a third aspect of the present invention inputs digital watermarked vector image data having a plurality of divided vectors in which a digital watermark is embedded, and specifies the plurality of divided vectors. Information including vector identification information for embedding, a plurality of types of codes that can be embedded as a digital watermark, and a bit coding rule indicating a division ratio assigned to each of the codes. Then, based on the vector specifying information in the secret information, the plurality of divided vectors are specified from the digital watermarked vector image data. Subsequently, the specified plurality of divided vectors are sorted into a set of two or more divided vectors corresponding to each of the two or more segments that were the source of the division. Subsequently, for each of the two or more segments, a division ratio of a corresponding set of division vectors is calculated, and a digital watermark is assigned to each segment based on the calculated division ratio and a bit coding rule in the secret information. Extract the embedded code as Then, by connecting the codes extracted for the two or more segments, digital watermark information embedded in the digital watermarked vector image data is obtained.

The above secret information (bit coding rules, etc.)
Can be managed so that only the copyright owner can hold it. As a result, only the copyright holder can extract the digital watermark from the digital watermarked vector image data.

In a preferred embodiment, when there is a suspicion of unauthorized copying or falsification of digital watermarked vector image data distributed on the market, digital watermark information is obtained from the digital watermarked vector image data by the above method. After the extraction, the digital watermark information is examined to determine whether or not the digital watermark-containing vector image data is indeed illegally copied or falsified.

A digital watermark information management system according to a fourth aspect of the present invention is a digital watermark information management system comprising: digital watermark information to be embedded in digital watermarked vector image data distributed on the market; A digital watermark information management database for storing and managing secret information necessary for extracting digital watermark information from the inside; input means for inputting digital watermarked vector image data obtained from the market; Extracting means for extracting digital watermark information from the watermarked vector image data using the secret information, and comparing the extracted digital watermark information with the digital watermark information managed in the digital watermark information management database It comprises a collating means and a result output means for outputting the collation result.

According to this system, it is possible to detect unauthorized copying or falsification of digital watermarked vector image data distributed on the market.

In a preferred embodiment, as a digital watermark to be embedded as a digital watermark, for example, product information or product identification information of vector-type image data, copyright information such as a copyright owner name, a creation date, and a logo mark; There is distribution information such as sales destinations and sales dates. Alternatively, only the product number or product identification information is embedded, and other copyright information and distribution information are linked with the product number or product identification information,
It is stored in a digital watermark information management database. By managing digital watermark information such as product numbers or product identification information in the digital watermark information management database, if there is a suspicion of unauthorized copying or tampering with vector-type image data distributed in the market, By extracting the embedded information and comparing / collating it with the information stored in the electronic watermark information management database, it becomes possible to track which sales destination and when the provided vector-type image data was illegally copied or falsified.

According to a fifth aspect of the present invention, in a computer-readable recording medium on which digital watermarked vector-type image data is recorded, the digital watermarked vector-type image data recorded thereon is converted to original vector-type image data. At least 2 divided from a vector selected from
It has a specific structure that includes at least two division vectors, at least two of which have a division ratio corresponding to a code embedded as a digital watermark.

This recording medium can be manufactured by embedding a digital watermark in original vector-type image data using the above-described digital watermark embedding method according to the present invention, and writing the data to the recording medium. From the digital watermarked vector image data recorded on the recording medium, the original image can be reproduced without deteriorating the quality, and the digital watermark information can be extracted.

Although the present invention can be typically implemented by a computer, a computer program for that can be installed or loaded on the computer through various media such as a disk storage, a semiconductor memory, and a communication network.

[0033]

Embodiments of the present invention will be described below with reference to the drawings.

First, an embodiment of a method for embedding a digital watermark in vector-type image data will be described.

In the present embodiment, each of one or more vectors selected from the original vector type image data is divided into a plurality of vectors (hereinafter, a division of the original vector is referred to as a "segment"). Is further divided into a plurality of (typically two) vectors (hereinafter, a segment obtained by dividing each segment is referred to as a “split vector”). 1 of "0" or "1" according to the division ratio
Correspond to bit code. Accordingly, each vector selected from the original image data is composed of a plurality of segments each representing a 1-bit code of “0” or “1”, and thus represents a multi-bit code. The vector thus divided becomes a digital watermark of the multi-bit code represented by the vector. In order to ensure resistance to attacks, a digital watermark is embedded by a method of performing scrambling processing of the above-described vector on a predetermined algorithm and arranging the vectors at random. This method is a method that can be applied to both vector type image data of monochrome and color images.

If the number of divided segments is increased to a desired number,
It becomes possible to embed a digital watermark with a larger number of bits. By embedding the digital watermark at more positions in the vector image data, the resistance to tampering and unauthorized copying is improved. By intentionally inserting a segment having a division ratio different from the specific vector division ratio corresponding to the 1-bit code as noise, it is possible to further improve the security of the watermark (= resistance to attacks).

As an example, a procedure for dividing one vector into three segments and embedding a 3-bit code as a digital watermark will be described below.

(1) Multiple segments S1 from vector V
Generation of ~ S3 One vector selected from the vector type image data is divided at an arbitrary position. For example, one vector V having a start point P1 and an end point Q3 as shown in FIG.
As shown in (1), it is divided (generated) into three segments S1 to S3. Start points P1, P2, and P3 and end points Q1, Q2, and Q3 are set in the segments S1 to S3, respectively. Here, segment S1 ~
Overlap of S3 is allowed, whereby the length of each of the segments S1 to S3 is sufficiently ensured, and the generation of the divided vector from each of the segments S1 to S3 is facilitated.

(2) Division of Each Segment For example, by dividing each segment into two divided vectors, the division ratio of the vector length corresponding to the 1-bit code “0” is set to “k: l” and the 1-bit code “ The division ratio corresponding to “1” is determined in advance as “m: n”. Here, by setting a variable allowable range in advance for the numerical value of the division ratio, it is possible to increase resistance to attack and noise addition. For example, the three segments S1 to
If the 3-bit code “011” is embedded in S3, the first digit S1 of the first digit is embedded in the first segment S1. Therefore, the first segment S1 having the start point P1 and the end point Q1 as shown in FIG.
As shown in FIG. 2 (C), with the division ratio “m: n” (which can be changed within a predetermined allowable range) corresponding to the 1-bit code “1”, the two divisions as shown in FIG. Vector dv
1. Divide into DV2.

For the purpose of extracting the digital watermark embedded in this way later on the copyright holder side for collation confirmation,
As secret information that can be held only by the copyright holder, a division rule (bit coding rule) for embedding a 1-bit code in a segment, that is, a division ratio of 1-bit code “0” is “k: l”, 1 bit The division ratio of the code “1” is information of “m: n”, information of the allowable range,
The information content "1" embedded in the segment, the absolute coordinate values (for example, in the case of a map image, the coordinate values corresponding to latitude and longitude) on the image of the start point P1 and the end point Q1 of the segment S1 in which it is embedded, and the segment The location of the S1 in the vector image data is stored in the digital watermark information management database.

(3) Division of All Segments The remaining segments S2 and S3 are also divided according to the same rule as in the above (2) to embed a 1-bit code. As a result, as shown in FIG. 3B, the second segment S2
Is divided into "m: n" and the 1-bit code "1" of the second digit
Is embedded, the third segment S3 is divided into “k: l”, and the 1-bit code “0” of the third digit is embedded. Similarly, for the second and third segments S2 and S3, the above confidential information that can be held only by the copyright owner (that is, as described in (2) above), but only when common May be stored in the digital watermark information management database.

(4) Scrambling of Divided Vectors As shown in FIG. 3B, divided vectors DV1 to DV6 divided from segments S1 to S3 have start points P1, T1 and P4, respectively.
2, T2, P3, T3 and end points R1, Q1, R2, Q2, R3, Q3 are set. Therefore, each of the divided vectors DV1 to DV6 is expressed as an independent vector.

First, these divided vectors DV1 to DV6 are
As shown in FIG. 4A, the original order (DV1, DV2,
DV3, DV4, DV5, DV6). Next, scramble processing of a predetermined algorithm is performed on these divided vectors DV1 to DV6. In this scrambling process, first, as shown in FIG.
From the original arrangement order of V6 (the order of DV1, DV2, DV3, DV4, DV5, DV6), as shown in FIG. 4B, a substantially random arrangement order different from the original (for example, DV3, DV6, DV2, D
V5, DV1, DV4 order). Next, as shown in FIG. 4B, in order to improve resistance to attacks, the second and subsequent divided vectors DV6, DV2,
For each of DV5, DV1, and DV4, a division vector DV3, DV6, DV2, DV5, and DV1 having the immediately preceding rank is selected, and the second and subsequent division vectors DV6, DV2, DV5, and DV are selected.
1, DV4 start point T3, T1, P3, P1, T2 and end point Q3, Q1, R3, R
1, the original absolute coordinate value of Q2 (for example, in the case of a map image,
Are the coordinate values corresponding to the latitude and longitude, and are indicated by circles), and the immediately preceding divided vectors DV3, DV6, DV
2. Convert the relative coordinate values (shown by triangles) measured from the end points R2, Q3, Q1, R3, and R1 of DV5 and DV1 (as shown by arrows). By this scrambling process, the code embedded as an electronic watermark in the division vectors DV1 to DV6 is descrambled and the original division vector DV1
Unless the expression of ~ DV6 is restored, it cannot be correctly extracted. In addition, from the representation of the scrambled divided vectors DV1 to DV6, the same figure as the original vector V cannot be reproduced unless the scramble is released and the representation of the original divided vectors DV1 to DV6 is restored. .

Then, as secret information that can be held only by a valid user of the vector type image data, a risk scramble (= descrambling operation) algorithm (ie, a divided vector after the scramble processing shown in FIG. 4B) is used. This is an algorithm for returning the expression to the original expression before the scrambling process shown in FIG. 4A. If the first divided vector DV3 shown in FIG. Algorithm for determining the second and subsequent divided vectors DV6 to DV4, returning their relative coordinate values to absolute coordinate values, restoring the relative arrangement to the arrangement before scrambling and restoring the original expression), and the above scrambling processing The identification information of the first divided vector DV6 and the absolute coordinate value of its end point R2, which are used as the basis for calculating the relative coordinate value, are digital watermark information. Store in the management database. The confidential information that can be held only by the legitimate user is distributed to the legitimate user together with the digital watermarked vector image data, and is used when the user restores the original vector image data. Also,
This confidential information is also held by the copyright holder, and is used when the copyright holder extracts a digital watermark.

By the above procedure, the digital watermark can be embedded in the vector image data. The information to be embedded as a digital watermark includes, for example, the product number or product identification information of the vector image data, the copyright information such as the name or name of the copyright owner, the creation date and a logo mark, and the sales destination and sale date. There is distribution information of. Alternatively, it is also possible to embed only the product number or product identification information as an electronic watermark, and store the other information in the electronic watermark information management database in association with the product number or the product identification.

The code representing information to be embedded as a digital watermark is practically seldom three bits as exemplified above, and usually has a considerably large number of bits.
When embedding such a multi-bit code as a digital watermark, one vector may be divided into a large number of segments and embedded therein. Alternatively, the multi-bit code may be divided into a plurality of sub-codes of a small number of bits. Decomposition may be performed, and a plurality of subcodes may be embedded in a plurality of vectors selected from the vector-type image data by the above procedure.

The above is one embodiment of a method for embedding a digital watermark in vector-type image data. Next, an embodiment of a method for restoring vector-type image data that can be reproduced from the digital-watermarked vector-type image data will be described. This restoration method can be performed only by a person having the above-mentioned secret information that can be held only by a legitimate user (that is, a legitimate user or a copyright owner).

The legitimate user obtains the above-mentioned secret information possessed only by the legitimate user (that is, the risk rumble algorithm, the identification information of the division vector used as the reference for the relative coordinate calculation, and the absolute coordinate value of its end point), Then, using the secret information, a division vector DV3 having the first arrangement order of scrambled division vectors DV3 to DV4 as shown in FIG. 5A is found from the digital watermarked vector image data. By subjecting the vector DV3 to the risk ramble processing, the divided vectors DV1 to DV6 before the scramble processing as shown in FIG. 5B are restored. In the image data after the risk rumble, a digital watermark is still embedded in the portion of the divided vectors DV1 to DV6, but the image itself represented is substantially the same as that of the original image data. (Ie the quality of the original image is not compromised at all). Therefore, it is possible to reproduce the same image as the original image from the digital watermarked image data after the risk rumble.

Next, an embodiment of a method for extracting digital watermark information from digital watermarked vector image data will be described. This extraction method can be performed only by a person who has both the above-mentioned secret information held only by the copyright owner and the above-mentioned secret information held only by the legitimate user (that is, the copyright owner).

(1) Risk Rumble of Divided Vectors First, the copyright owner first sets secret information (algorithm of risk rumble, identification information of the divided vectors used as a basis for calculation of relative coordinates, (End point absolute coordinate value), risk-ramble the divided vector in which the digital watermark is embedded in the same manner as the above-described restoration method, convert the relative coordinates into absolute coordinates, and change the arrangement order to the original arrangement order. return.

(2) Calculation of Segment Split Ratio Next, the split vectors that have returned to the original arrangement order are sorted into pairs of adjacent split vectors (that is, split from each segment). Alternatively, the coordinates of the start point and end point of the divided vector returned to the original arrangement order, and secret information (bit coding rules, information content embedded in each segment, and the start point and end point of each segment , Etc.), a pair of divided vectors corresponding to each segment is specified based on the coordinate values of the start point and end point of each segment. Then, the division ratio of each segment is calculated based on the coordinate values of the start point and the end point of each pair of divided vectors.

(3) Extraction of Digital Watermark Information Next, secret information held only by the copyright holder (bit coding rules, information contents embedded in each segment, and coordinate values of the start point and end point of each segment, etc.) The division ratio "m: n", "k: l" and 1
Based on the correspondence between the bit codes “1” and “0”, a 1-bit code “1” or “0” corresponding to the calculated division ratio of each segment (that is, embedded in each segment) is extracted. . Information content of all segments "1"
Alternatively, by extracting and connecting “0”, the entire information embedded as a digital watermark is determined.

Next, an embodiment of a computer system for managing digital watermark information by comprehensively using the above-described digital watermark embedding method, image data restoring method, and digital watermark extracting method will be described. explain.

FIG. 6 shows the overall configuration of an embodiment of the digital watermark information management system. The configuration and operation of this system 100 are as follows.

The system 100 includes a digital watermark embedding unit 10 and a digital watermark extracting / collating unit 20.

The digital watermark embedding section 10 has a digital watermark embedding mechanism / digital watermark information management mechanism 14, and thereby, the vector type image data 13 to be protected by copyright.
For each individual product, by the above-described embedding method, as a digital watermark, the product number or product identification information of the product or the above-mentioned copyright information (for example, the name or name of the copyright owner, the date of creation, Information 12 such as copyright information such as a logo mark and the above-mentioned distribution information (for example, sales destination and date of sale) is embedded, and the embedded information 12 and the various secrets described above created at the time of embedding are embedded. The information is stored and stored in the digital watermark information management database 16A. In addition, instead of embedding the product number, product identification information, copyright information, etc. all as a digital watermark,
Only basic information such as a product number or product identification information is embedded in the image data 13 as a digital watermark, and the remaining related information such as copyright information and distribution information is linked to the embedded product number or product identification information. May be stored in the digital watermark information management database 16A.

Image data product 30 distributed in market 200
Contains the vector-type image data in which the digital watermark is embedded as described above, and the above-described secret information that can be stored only by a valid user. A legitimate user who has obtained the product 30 uses the vector-type image data restoring / displaying mechanism 41 mounted on his / her personal computer, for example, and only the legitimate user within the product 30 can use the restoring method described above. By referring to the confidential information that can be stored, it is possible to risk-ramble the digital watermarked vector image data in the product 30, and reproduce and display an image of exactly the same quality as the image of the original vector image data.

If the user 50 suspects that the digital watermarked vector image data in the product 30 is illegally copied or falsified and distributed to the market 200, the copyright Obtains from the market 200 digital watermarked vector-type image data suspected of being illegally copied or tampered with, and extracts and extracts the digital watermark.
By entering the data into the collating unit 20, it is possible to check whether or not the data has been illegally copied or falsified.

That is, the digital watermark extracting / collating unit 20
Are a digital watermark information management mechanism 21, a digital watermark collation mechanism 22, a digital watermark extraction mechanism 24, and a collation result display mechanism 26.
And The digital watermark information management mechanism 21 may be the digital watermark information management database 16B (the digital watermark information management database 16A itself) having substantially the same contents as the digital watermark information management database 16A created by the digital watermark embedding unit 10. ).

The digital watermark extracting mechanism 24 inputs the digital watermarked vector-type image data 23 obtained from the market 200 and suspected of unauthorized copying or falsification, and corresponds to the input digital watermarked vector-type image data 23. It requests the digital watermark information management mechanism 21 to search the stored information from the database 16B. Then, the digital watermark extracting mechanism 24 receives secret information that can be held only by the copyright holder and secret information that can be held only by the legitimate user from the stored information searched by the digital watermark information managing mechanism 21, and refers to it. Then, according to the above-described digital watermark extraction method, information 25 (basic information such as a product number and product identification information and copyright information) embedded in the suspicious digital watermark And related information such as distribution information, and may be only basic information as described above).

The digital watermark collating mechanism 22 includes a product number,
Receive product identification information, copyright information, distribution information, etc.,
Then, the extracted embedding information 25 is collated with the extracted embedding information 25. The collation result is displayed on the extracted information collation result display screen 27 by the collation result display mechanism 26. From the displayed collation result, the operator can determine whether or not the suspicious digital watermarked vector image data 23 is indeed illegally copied or falsified. For example, if the collation results are identical, and the image data 23 flows through a distribution channel that is not determined to be valid from the copyright information or the distribution information,
It can be determined that the copy is illegal. Alternatively, if the collation results match and the image reproduced from the image data 23 does not completely match the original image,
It can be determined that it has been tampered with.

The embodiment of the present invention has been described above.
The above embodiment is merely an example for describing the present invention, and is not intended to limit the present invention to only the above embodiment. Therefore, the present invention can be implemented in various modes other than the above-described embodiment. For example, in the above-described embodiment, one vector is divided into a plurality of segments, and each segment is divided into a plurality of divided vectors at a division ratio according to an embedding code. This may be omitted, and one vector may be directly divided into a plurality of divided vectors at a division ratio according to the embedding code. Further, for example, in the above embodiment, a predetermined division ratio of a segment is assigned to a 1-bit code, but a predetermined division ratio of a segment may be assigned to a plurality of bit codes. For example, the division ratio “m: n” for the 2-bit code “00”, the division ratio “k: l” for the 2-bit code “01”, and the division ratio “k: l” for the 2-bit code “10” "p: q" is assigned a division ratio "s: t" to the 2-bit code "11", and so on. Further, the segment may be divided into three or more divided vectors, and the division ratio of the three or more divided vectors may be assigned to a 1-bit or multiple-bit code. For example, three division ratios “l: m: n” are assigned to one-bit code “0”, and three division ratios “p: q: r” are assigned to one-bit code “1”. . Also,
When scrambling a plurality of divided vectors generated from one original vector, scramble not only those divided vectors but also other vectors (in extreme cases, scramble all image data). Is also good.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which one vector V is divided into a plurality of segments S1 to S3.

FIG. 2 shows that one segment S1 is divided into two divided vectors DV
FIG. 3 is a diagram showing a state in which a 1-bit code is embedded by dividing into 1 and DV2.

FIG. 3 is a diagram showing a manner in which the remaining segments S2 and S3 are similarly divided and a 1-bit code is embedded.

FIG. 4 is a diagram showing a state in which scrambling is performed on divided vectors DV1 to DV6.

FIG. 5 is a diagram showing a state of a risk rumble process.

FIG. 6 is a block diagram showing the overall configuration of an embodiment of a digital watermark information management system.

[Explanation of symbols]

V Original vectors S1 to S3 Segments obtained by dividing original vectors DV1 to DV6 Divided vectors obtained by dividing segments 100 Digital watermark information management system 10 Digital watermark embedding unit 20 Digital watermark extracting / collating unit 12 Embedded information 13 Original vector image data 14 Digital Watermark Embedding Mechanism / Digital Watermark Information Management Mechanism 16A, 16B Digital Watermark Information Management Database 21 Digital Watermark Information Management Mechanism 22 Digital Watermark Verification Mechanism 23 Vector Type Image Data Suspected of Unauthorized Copying or Falsification 24 Digital Watermark Extraction Mechanism 25 Extracted Embedded information

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naohisa Komatsu 3-4-1 Okubo, Shinjuku-ku, Tokyo Waseda University Faculty of Science and Technology (72) Inventor Makoto Kurihara 3-4-1 Okubo Shinjuku-ku, Tokyo Waseda F-term (reference) in the Faculty of Science and Technology of Ta University 5B057 AA13 AA20 CA17 CB17 CG07 5C076 AA14 BA06 5C077 LL14 PP21 PP23 PQ08 5J104 AA14 PA00

Claims (19)

[Claims] A step of selecting a vector from original vector image data; and a step of dividing the vector into at least two divided vectors at a predetermined division ratio assigned to a code to be embedded in the vector as a digital watermark. A method for embedding a digital watermark in vector-type image data provided with. 2. Dividing the vector into a plurality of segments; and dividing each segment into at least two divided vectors at a predetermined division ratio assigned to a code to be embedded in each segment as a digital watermark. The method of claim 1 comprising: 3. A step of subjecting a plurality of divided vectors to a scramble process of a predetermined algorithm for converting original coordinate values of a start point and an end point of at least one divided vector into another coordinate value. The method of claim 1, further comprising: 4. The step of performing the scrambling process includes: (1) obtaining another arrangement order from the original arrangement order of the plurality of divided vectors; and (2) at least one of the plurality of divided vectors. For the divided vector, selecting another divided vector having a predetermined order relationship in the another arrangement order; (3) changing the original coordinate values of the start point and the end point of the at least one divided vector to the another Converting the divided vector into a relative coordinate value measured from a start point or an end point of the divided vector. 5. A means for selecting a vector from original vector-type image data; and means for dividing the vector into at least two divided vectors at a predetermined division ratio assigned to a code to be embedded in the vector as a digital watermark. A system for embedding digital watermarks in vector image data with. 6. A means for dividing the vector into a plurality of segments, and means for dividing each segment into at least two divided vectors at a predetermined division ratio assigned to a code to be embedded as a digital watermark in each segment. The system of claim 5 comprising: 7. A predetermined algorithm for converting original coordinate values of a start point and an end point of at least one of the plurality of divided vectors into another coordinate value for the plurality of divided vectors. 6. The system according to claim 5, further comprising: means for performing a scrambling process. 8. The means for performing the scrambling process includes: (1) means for obtaining another arrangement order from the original arrangement order of the plurality of divided vectors; and (2) at least one of the plurality of divided vectors. Means for selecting another divided vector having a predetermined order relationship in the another array order with respect to the divided vector, (3) the original coordinate values of the start point and the end point of the at least one divided vector, 8. A system according to claim 7, further comprising means for converting the divided vector into a relative coordinate value measured from a start point or an end point. 9. A step of selecting a vector from original vector-type image data; and a step of dividing the vector into at least two divided vectors at a predetermined division ratio assigned to a code to be embedded in the vector as a digital watermark. And a computer-readable recording medium recording a program for causing a computer to execute the program. 10. An original image including a plurality of divided vectors embedded with a digital watermark and subjected to scramble processing, and the same original image as the original vector type image data can be reproduced before the scramble processing is performed. Receiving the vector image data with the digital watermark included therein, receiving the secret information including the vector specifying information for specifying the plurality of divided vectors, and the algorithm of the risk scramble process which is the reverse operation of the scramble process. A step of specifying the plurality of divided vectors from the digital watermarked vector image data based on the vector specifying information in the secret information; and for the specified plurality of divided vectors, By performing the risk rumble process in the confidential information, Restoring the divided vector of the original image to the original state before the scramble processing is performed. The method of restoring the reproducible vector image data of the original image from the digital watermarked vector image data. 11. An electronic watermark including a plurality of divided vectors embedded with a digital watermark and subjected to scramble processing, and the same original image as the original vector image data can be reproduced before the scramble processing is performed. Means for inputting the digital watermarked vector-type image data, vector specifying information for specifying the plurality of divided vectors, and secret information including an algorithm of a risk rumble process which is a reverse operation of the scramble process. Means for inputting, means for specifying the plurality of divided vectors from the digital watermarked vector image data based on the vector specifying information in the secret information, Performing the risk rumble process in the secret information, Means for restoring the original image to a reproducible vector type image data from the digital watermarked vector type image data, comprising means for restoring the vector to the original state before the scramble processing is performed. 12. A plurality of divided vectors in which a digital watermark is embedded and subjected to scramble processing, and before the scramble processing is performed, the same original image as the original vector type image data can be reproduced. Receiving the vector image data with the digital watermark included therein, receiving the secret information including the vector specifying information for specifying the plurality of divided vectors, and the algorithm of the risk scramble process which is the reverse operation of the scramble process. A step of specifying the plurality of divided vectors from the digital watermarked vector image data based on the vector specifying information in the secret information; and for the specified plurality of divided vectors, By performing the risk rumble process in the confidential information, Restoring the divided vector to the original state before the scramble processing is performed on the computer. 13. Receiving digital watermarked vector-type image data having a plurality of division vectors in which a digital watermark is embedded, vector specifying information for specifying the plurality of division vectors, and embedding as a digital watermark. Receiving secret information including a plurality of kinds of codes and a bit coding rule indicating a division ratio assigned to each of the codes; and, based on the vector specifying information in the secret information, the digital watermarked vector type. Specifying the plurality of divided vectors from within image data; and converting the specified plurality of divided vectors into two or more divided vectors corresponding to each of two or more segments from which the plurality of divided vectors were divided. And sorting each of the two or more segments. Calculating a division ratio of a set of division vectors, and extracting a code embedded as a digital watermark in each segment based on the calculated division ratio and the bit coding convention in the secret information; Linking the codes extracted for two or more segments to obtain information embedded as a digital watermark in the digital watermarked vector image data, the digital watermark information from the digital watermarked vector image data. How to extract. 14. A step of determining whether or not the digital watermarked vector image data is fraudulently created by examining information embedded as a digital watermark in the digital watermarked vector image data. 14. The method of claim 13, further comprising: 15. A means for receiving digital watermarked vector-type image data having a plurality of division vectors embedded with a digital watermark, vector specifying information for specifying the plurality of division vectors, and embedding as a digital watermark. Means for receiving secret information including a plurality of kinds of codes and a bit coding rule indicating a division ratio assigned to each of the codes, and a vector type with the electronic watermark based on the vector specifying information in the secret information. Means for specifying the plurality of divided vectors from within the image data, and two or more divided vectors corresponding to each of the two or more segments from which the plurality of divided vectors were divided. Means for associating the two or more segments with each other. Means for extracting a code embedded as an electronic watermark in each segment based on the calculated division ratio and the bit coding convention in the secret information; and Means for obtaining the information embedded as a digital watermark in the digital watermarked vector image data by connecting the codes extracted for the digital watermarking, extracting digital watermark information from the digital watermarked vector image data. System. 16. A means for judging whether or not the digital watermarked vector image data is fraudulently created by checking information embedded as a digital watermark in the digital watermarked vector image data. The system of claim 15, further comprising: 17. Receiving digital watermarked vector-type image data having a plurality of division vectors in which a digital watermark is embedded, vector specifying information for specifying the plurality of division vectors, and embedding as a digital watermark. Receiving secret information including a plurality of kinds of codes and a bit coding rule indicating a division ratio assigned to each of the codes; and, based on the vector specifying information in the secret information, the digital watermarked vector type. Specifying the plurality of divided vectors from within image data; and converting the specified plurality of divided vectors into two or more divided vectors corresponding to each of two or more segments from which the plurality of divided vectors were divided. And sorting each of the two or more segments. Calculating a division ratio of a set of division vectors, and extracting a code embedded as a digital watermark in each segment based on the calculated division ratio and the bit coding convention in the secret information; Connecting the codes extracted for two or more segments to obtain information embedded as a digital watermark in the digital watermarked vector-type image data. Recording medium. 18. Digital watermark information to be embedded in digital watermarked vector image data distributed on the market, and necessary for extracting the digital watermark information from the digital watermarked vector image data. Digital watermark information management database for storing and managing secret information; input means for inputting digital watermarked vector image data obtained from the market; and digital watermarked vector image data input by the input means. Extracting means for extracting the digital watermark information using the secret information managed by the digital watermark information management database; and the digital watermark information extracted by the extracting means; and Collating means for collating the managed digital watermark information; Electronic watermark information management system for detection and result output means for outputting the collation result from the stage, with a, a watermarked vector-type image data created illegally from the market. 19. At least two divided vectors obtained by dividing a vector selected from original vector-type image data, wherein the at least two divided vectors have a division ratio corresponding to a code embedded as a digital watermark. A computer-readable recording medium for recording digital watermarked vector image data having a specific structure.