JP4178757B2 - Image processing system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing system for embedding a digital watermark in image data.
[0002]
[Prior art]
As for the digital watermark embedding technique for the purpose of preventing image falsification, for example, Japanese Patent Laid-Open No. 2000-287065 and Japanese Patent Laid-Open No. 2000-28706. 6 There are those disclosed in the Gazette. A conventional image processing system will be described with reference to FIGS.
[0003]
The conventional image processing system 1 includes a digital watermark embedding device 10 and a digital watermark extraction device 20 as shown in FIG. The digital watermark embedding device 10 includes a document identification unit 11, a document format database unit 12, a digital watermark embedding unit 13, a watermark key generation unit 14, and an encryption unit 15. The digital watermark extraction device 20 includes a digital watermark extraction unit. 21 and a decoding unit 22. The image processing system 1 generates an original image 35 by embedding an electronic watermark into an original image 31 obtained from various documents, and extracts an electronic watermark from the original image 35 to determine whether the image has been tampered with. It has a function to do.
[0004]
The document identification unit 11 provided in the digital watermark embedding apparatus 10 recognizes the characteristics of the original image 31 read from the document (form) by the scanner, for example, identifies the document type, and stores document information 32 indicating the document type. It is transmitted to the document format database unit 12.
[0005]
An example of the original image 31 is shown in FIG. The original image 31 has a plurality of pieces of information that should be prevented from being falsified. Each information is distributed and described in a plurality of areas. For example, the date “January 31, 1999” is written in the first area R1, the certificate number “01234456789” is written in the second area R2, and the name “Yamada Taro” is written in the third area R3. And the name “Taro Yamada” is described in the fourth region R4. Further, in the area Rx of the original image 31, an identification number “12345” for identifying a document related to the original image 31 is described. The document identifying unit 11 identifies the identification number “1234” described in the region Rx. 5 ”To identify the document type.
[0006]
As shown in FIG. 18, the document format database unit 12 manages information such as coordinates of an area in which a digital watermark is to be embedded in the form of a document format information table for each document type. When document information 32 is sent from the document identification unit 11, the document format database unit 12 selects document format information 33 that matches the document information 32 from the document format information table, and selects the selected document format information 33 as an electronic document. This is given to the watermark embedding unit 13 and the encryption unit 15.
[0007]
The watermark key generation unit 14 generates a watermark key 34 and transmits the generated watermark key 34 to the digital watermark embedding unit 13 and the encryption unit 15.
[0008]
Based on the document format information 33 given from the document format database unit 12, the digital watermark embedding unit 13 embeds a digital watermark only in a specific area in the original image 31 using the watermark key 34 to generate an original image 35. To do. FIG. 19 shows a part of the original image 35. Here, a rectangular area having the coordinates (x11, y11) and the coordinates (x21, y21) as diagonals is designated as a range for preventing the image of the first area R1 from being altered, and the coordinates (x12, y12) and the coordinates ( A rectangular area whose diagonal is x22, y22) is designated as a range for preventing the image of the second area R2 from being falsified. A digital watermark is embedded in each range. In FIG. 19, the digital watermark is represented by oblique lines, but is actually embedded so as to be invisible.
[0009]
The encryption unit 15 encrypts the document format information 33 and the watermark key 34 based on a predetermined algorithm, and generates the encrypted document format information 33enc and the encrypted watermark key 34enc.
[0010]
The original image 35, the encrypted document format information 33enc, and the encrypted watermark key 34enc output from the digital watermark embedding device 10 are received by the digital watermark extraction device 20.
[0011]
The decryption unit 22 provided in the digital watermark extraction apparatus 20 decrypts the encrypted document format information 33enc and the encrypted watermark key 34enc into the document format information 33 and the watermark key 34, respectively.
[0012]
The digital watermark extraction unit 21 extracts a digital watermark from the original image 35 using the document format information 33 and the watermark key 34. The digital watermark extracted here matches the digital watermark embedded in the original image 31 in the digital watermark embedding device 10 if the original image 35 has not been tampered with. That is, by checking the digital watermark extracted by the digital watermark extraction unit 21, it is determined whether the original image 35 has been tampered with.
[0013]
[Problems to be solved by the invention]
However, according to the conventional image processing system 1, if the document format is the same, the area where the digital watermark is embedded is fixed. For this reason, there is a possibility that an area in which a digital watermark is embedded is specified by a third party comparing images of the same document format.
[0014]
Once the area in which the digital watermark is to be embedded is specified, the original image can be easily generated. In this case, by preparing watermark keys with slightly different contents and applying these watermark keys to the same original image, it is possible to analyze the algorithm for embedding / extracting the digital watermark from the generated original image. Become. If this algorithm is clarified, it becomes possible to perform alteration on the original image, which cannot be detected by the digital watermark extracting apparatus 20.
[0015]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an image processing system capable of making it difficult to specify a digital watermark embedding area by a third party. is there.
[0016]
[Means for Solving the Problems]
In order to solve the above-described problems, according to the present invention, one or more tamper-proof areas for preventing tampering are selected from an image, and digital watermark embedding including a part or all of each tamper-proof area is performed. There is provided an image processing system including a digital watermark embedding device that sets a region, embeds a digital watermark in a digital watermark embedding region, and generates a digital watermark embedded image. The electronic watermark embedding apparatus has a function of changing at least one of the position, size, or shape of the electronic watermark embedding area (claim 1). According to such a configuration, since the digital watermark is not embedded in a fixed range, it is difficult for a third party to specify the digital watermark embedding position.
[0017]
It is preferable that the digital watermark embedding apparatus has a random number generation unit that generates a random number. By generating a random number each time the digital watermark embedding process is performed, at least one of the position, size, or shape of the digital watermark embedding area changes for each digital watermark embedding process. This makes it more difficult to specify the embedded position of the digital watermark.
[0018]
A plurality of digital watermark embedding areas may be set for one falsification prevention area, or one digital watermark embedding area may be set for a plurality of falsification prevention areas. Item 3, 4). In either case, it leads to the difficulty of specifying the embedded position of the digital watermark.
[0019]
Furthermore, after setting one digital watermark embedding area for a plurality of tamper-proof areas, the digital watermark embedding area is divided into a plurality of digital watermark embedding sub-areas, and a digital watermark is added to each digital watermark embedding sub-area. Embedding is also effective in that it is difficult to specify the embedding position of the digital watermark.
[0020]
It is preferable that the division position when forming a plurality of digital watermark embedding sub-regions from the digital watermark embedding region is determined based on a random number generated by a random number generation unit provided in the digital watermark embedding device. By generating a random number every time the digital watermark embedding process is performed, the division position changes for each digital watermark embedding process. It becomes more difficult to specify the embedded position of the digital watermark.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of an image processing system according to the present invention will be described below in detail with reference to the accompanying drawings. In the following description and the attached drawings, constituent elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted.
[0022]
[First Embodiment]
FIG. 1 shows the configuration of an image processing system 101 according to the first embodiment of the present invention. The image processing system 101 includes a digital watermark embedding device 110 and a digital watermark extraction device 20. The digital watermark embedding device 110 includes a document identification unit 11, a document format database unit 12, a digital watermark embedding unit 13, a watermark key generation unit 14, an encryption unit 15, a random number Generation A section 111 and a difference document format information generation section 112. In addition, the digital watermark extraction apparatus 20 includes a digital watermark extraction unit 21 and a decoding unit 22. The image processing system 101 generates an original image 135 by embedding an electronic watermark in the original image 31 obtained from various documents, and extracts the electronic watermark from the original image 135 to determine whether the image has been tampered with. It has a function to do.
[0023]
The document identification unit 11 provided in the digital watermark embedding apparatus 110 captures the characteristics of the original image 31 read from the document (form) by the scanner, for example, identifies the document type, and stores document information 32 indicating the document type. It is transmitted to the document format database unit 12.
[0024]
An example of the original image 31 is as shown in FIG. The original image 31 has a plurality of pieces of information that should be prevented from being falsified. Each information is distributed and described in a plurality of areas. For example, the date “January 31, 1999” is written in the first area R1, the certificate number “01234456789” is written in the second area R2, and the name “Yamada Taro” is written in the third area R3. And the name “Taro Yamada” is described in the fourth region R4. Further, in the area Rx of the original image 31, an identification number “12345” for identifying a document related to the original image 31 is described. The document identifying unit 11 identifies the identification number “1234” described in the region Rx. 5 ”To identify the document type. Although the identification number is used here to identify the document type, it is also possible to identify the document type from, for example, a frame (ruled line) or character sequence in the image. is there.
[0025]
As shown in FIG. 18, the document format database unit 12 manages information such as coordinates of an area in which a digital watermark is to be embedded in the form of a document format information table for each document type. When the document information 32 is sent from the document identification unit 11, the document format database unit 12 gives the document format information 33 that matches the document information 32 to the difference document format information generation unit 112.
[0026]
The random number generation unit 111 is based on various information such as information unique to the digital watermark embedding device 110 (for example, a MAC address), an ID number of a user of the digital watermark embedding device 110, a date and time when image processing is performed, and the like. A pseudo random number 131 is generated. The pseudo random number 131 is transmitted to the difference document format information generation unit 112.
[0027]
The difference document format information generation unit 112 determines four values for each region in which a digital watermark is embedded from one pseudo random number 131. In order to facilitate the determination of the four values, the difference document format information generation unit 112 includes a table indicating the correspondence between pseudorandom numbers and the four values, for example. These four values are added to the document format information 33 as difference information. As a result, difference document format information 133 is generated. The difference document format information 133 is transmitted to the digital watermark embedding unit 13 and the encryption unit 15. FIG. 2 shows difference information about the first region R1 in which information to be prevented from being falsified (here, “January 31, 1999”) is described. FIG. The difference document format information 133 obtained by adding to the format information 33 is shown.
[0028]
The watermark key generation unit 14 transmits the watermark key 34 to the digital watermark embedding unit 13 and the encryption unit 15.
[0029]
The digital watermark embedding unit 13 embeds a digital watermark only in a specific area in the original image 31 using the watermark key 34 based on the difference document format information 133 given from the difference document format information generation unit 112, 135 is generated. FIG. 4 shows a part of the original image 135. As shown in the figure, a rectangular area whose coordinates are (x11 + Δx1, y11 + Δy1) and coordinates (x21 + Δx2, y21 + Δy2) is a range that prevents alteration of the image in the first area R1 (hereinafter, “first shift area R1s”). Specified as A digital watermark is embedded in the first shift region R1s.
[0030]
Here, the first shift region R1s has a larger area than the first region R1 and includes the first region R1, but the area and position of the first shift region R1s change according to the pseudo-random number generated by the random number generation unit 111. To do. For example, the first shift region R1s and the first region R1 may be similar, and the first shift region R1s may be shifted in the X-axis direction and the Y-axis direction with respect to the first region R1. In FIG. 4, the digital watermark is represented by oblique lines, but is actually embedded so as to be invisible. Hereinafter, the embodiment of the present invention will be described in the case where the shift area in which the digital watermark is embedded is a rectangular area specified from two coordinates. The rectangular area is, for example, an upper left corner coordinate and a width, You may make it represent in the format of height (x, y, w, h). Also, the shift area can be other than a rectangle.
[0031]
By the way, the differential document format information generation unit 112 generates differential document format information for each region (for example, the first region R1 and the second region R2) that should be prevented from being falsified. As described above, the shift area (for example, the first shift area R1s) in which the digital watermark is actually embedded is determined based on each difference document format information. The difference document format information generation unit 112 adjusts each difference document format information so that the shift areas do not overlap when generating the difference document format information, and then outputs the difference document format information to the digital watermark embedding unit 13.
[0032]
The encryption unit 15 encrypts the differential document format information 133 and the watermark key 34 based on a predetermined algorithm, and generates the encrypted differential document format information 133enc and the encrypted watermark key 34enc.
[0033]
The original image 135, the encrypted differential document format information 133enc, and the encrypted watermark key 34enc output from the digital watermark embedding device 110 are received by the digital watermark extraction device 20.
[0034]
The decrypting unit 22 provided in the digital watermark extracting apparatus 20 decrypts the encrypted differential document format information 133enc and the encrypted watermark key 34enc into the differential document format information 133 and the watermark key 34, respectively.
[0035]
The digital watermark extraction unit 21 extracts a digital watermark from the original image 135 using the difference document format information 133 and the watermark key 34. The digital watermark extracted here matches the digital watermark embedded in the original image 31 in the digital watermark embedding device 110 if the original image 135 has not been tampered with. That is, by checking the digital watermark extracted by the digital watermark extraction unit 21, it is determined whether the original image 135 has been tampered with.
[0036]
As described above, according to the image processing system 101 according to the first embodiment, the embedded position of the digital watermark in the image and the size or shape of the embedded area correspond to the pseudo-random number generated in the random number generation unit 111. Will change. For this reason, even if the same watermark key 34 is applied to the same original image 31, the digital watermark is embedded in the same range if the digital watermark embedding device 110, the user of the digital watermark embedding device 110, or the use date and time are different. Things are extremely rare. Since the digital watermark embedding range changes sequentially, it becomes difficult to specify the range by a third party, and thus to analyze an algorithm related to digital watermark embedding / extraction.
[0037]
Further, according to the image processing system 101 according to the first embodiment, since an electronic watermark is not embedded in an area that does not require tampering prevention (for example, a blank part or a part where a fixed sentence is written), the electronic watermark is not embedded. An increase in the size of image data due to embedding a watermark can be minimized. In addition, the image processing time can be shortened.
[0038]
[Second Embodiment]
FIG. 5 shows a configuration of an image processing system 201 according to the second embodiment of the present invention. The image processing system 201 includes a digital watermark embedding device 210 and a digital watermark extraction device 20. The digital watermark embedding apparatus 210 includes a document identification unit 11, a document format database unit 12, a digital watermark embedding unit 13, a watermark key generation unit 14, an encryption unit 15, a random number Generation A section 111 and a divided document format information generation section 212. In addition, the digital watermark extraction apparatus 20 includes a digital watermark extraction unit 21 and a decoding unit 22. The image processing system 201 generates an original image 235 by embedding an electronic watermark into the original image 31 obtained from various documents, and extracts the electronic watermark from the original image 235 to determine whether the image has been tampered with. It has a function to do.
[0039]
The document identification unit 11 provided in the digital watermark embedding apparatus 210 recognizes the characteristics of the original image 31 read from the document (form) by the scanner, for example, identifies the document type, and stores document information 32 indicating the document type. It is transmitted to the document format database unit 12.
[0040]
The document format database unit 12 provides the document format information 33 that matches the document information 32 to the divided document format information generation unit 212.
[0041]
The random number generator 111 is a digital watermark embedding device. 2 10 unique information (for example, MAC address), digital watermark embedding device 2 A pseudo random number 131 is generated based on various information such as the ID number of 10 users, the date and time when image processing was performed, and the like. The pseudo random number 131 is transmitted to the divided document format information generation unit 212.
[0042]
The divided document format information generation unit 212 determines one value for each region in which the digital watermark is embedded from one pseudo random number 131. Split document format information generator to facilitate the determination of one value 2 12 includes a table indicating the correspondence between a pseudo-random number and one value, for example. The divided document format information generation unit 212 uses this value as division information and derives the divided document format information 233 from the division information and the document format information 33. The divided document format information 233 is transmitted to the digital watermark embedding unit 13 and the encryption unit 15. FIG. 6 shows division information for the first region R1 in which information that should be prevented from being falsified (here, “January 31, 1999”) is shown. FIG. 7 shows the division information and the document. The divided document format information 233 derived from the format information 33 is shown.
[0043]
The watermark key generation unit 14 transmits the watermark key 34 to the digital watermark embedding unit 13 and the encryption unit 15.
[0044]
The digital watermark embedding unit 13 embeds a digital watermark only in a specific area in the original image 31 using the watermark key 34 based on the divided document format information 233 given from the divided document format information generation unit 212, and the original image 235 is generated. FIG. 8 shows a part of the original image 235. As shown in the figure, a rectangular first divided region R1d1 having the coordinates (x11, y11) and the coordinates (x11 + γx, y21) as diagonals, and the coordinates (x11 + γx, y11) and the coordinates (x21, y21) as diagonals. The rectangular second divided region R1d2 is designated as a range for preventing falsification of the image in the first region R1. The same or different digital watermarks are embedded in the first divided region R1d1 and the second divided region R1d2.
[0045]
The first divided region R1d1 and the second divided region R1d2 are obtained by dividing the first region R1 into two in the Y-axis direction, and the division positions thereof are determined according to the pseudo-random number generated by the random number generation unit 111. Change. Further, the number of divisions need not be limited to two. Further, the divided document format information generation unit 212 can derive the divided document format information 233 ′ shown in FIG. 10 by using the division information shown in FIG. In this case, as shown in FIG. 11, a first divided region R1d1 ′ and a second divided region R1d2 ′ that divide the first region R1 in the X-axis direction are obtained. Then, a digital watermark may be embedded in the first divided region R1d1 ′ and the second divided region R1d2 ′.
[0046]
The encryption unit 15 encrypts the divided document format information 233 and the watermark key 34 based on a predetermined algorithm, and generates the encrypted divided document format information 233enc and the encrypted watermark key 34enc.
[0047]
The original image 235, the encrypted divided document format information 233enc, and the encrypted watermark key 34enc output from the digital watermark embedding apparatus 210 are received by the digital watermark extraction apparatus 20.
[0048]
The decryption unit 22 provided in the digital watermark extracting apparatus 20 decrypts the encrypted divided document format information 233enc and the encrypted watermark key 34enc into the divided document format information 233 and the watermark key 34, respectively.
[0049]
The digital watermark extraction unit 21 extracts a digital watermark from the original image 235 using the divided document format information 233 and the watermark key 34. The digital watermark extracted here matches the digital watermark embedded in the original image 31 in the digital watermark embedding device 210 if the original image 235 has not been tampered with. That is, by checking the digital watermark extracted by the digital watermark extraction unit 21, it is determined whether the original image 235 has been tampered with.
[0050]
As described above, according to the image processing system 201 according to the second embodiment, the digital watermark embedding range is divided. Then, the division position changes according to the pseudo random number generated in the random number generation unit 111. For this reason, even if the same watermark key 34 is applied to the same original image 31, if the digital watermark embedding device 210, the user of the digital watermark embedding device 210, or the use date and time are different, the division positions will be different. Since the division position of the embedded area of the digital watermark changes sequentially, it becomes extremely difficult to specify the position by a third party. Therefore, similarly to the first embodiment, it is difficult to analyze an algorithm related to digital watermark embedding / extraction.
[0051]
[Third Embodiment]
FIG. 12 shows the configuration of an image processing system 301 according to the third embodiment of the present invention. The image processing system 301 includes a digital watermark embedding device 310 and a digital watermark extraction device 20. The digital watermark embedding device 310 includes a document identification unit 11, a document format database unit 12, a digital watermark embedding unit 13, a watermark key generation unit 14, an encryption unit 15, a random number Generation A conversion unit 111 and a converted document format information generation unit 312. In addition, the digital watermark extraction apparatus 20 includes a digital watermark extraction unit 21 and a decoding unit 22. The image processing system 301 generates an original image 335 by embedding an electronic watermark in the original image 31 obtained from various documents, and extracts the electronic watermark from the original image 335 to determine whether the image has been tampered with. It has a function to do.
[0052]
The document identification unit 11 provided in the digital watermark embedding apparatus 310 recognizes the characteristics of the original image 31 read from the document (form) by the scanner, for example, identifies the document type, and stores document information 32 indicating the document type. It is transmitted to the document format database unit 12.
[0053]
The document format database unit 12 provides the document format information 33 that matches the document information 32 to the converted document format information generation unit 312.
[0054]
The random number generation unit 111 is based on various information such as information unique to the digital watermark embedding device 310 (for example, a MAC address), an ID number of the user of the digital watermark embedding device 310, and the date and time when the image processing was performed. A pseudo random number 131 is generated. The pseudo random number 131 is transmitted to the converted document format information generation unit 312.
[0055]
As shown in FIG. 13, the converted document format information generation unit 312 includes a second region R2, a third region R3, and a fourth region that are in contact with each other among a plurality of regions that should be prevented from being falsified in the original image 31. For R4, as shown in FIG. 14, a rectangular conversion region Rc including these is set. Of the plurality of areas that should be prevented from being tampered with, for the area that is not in contact with other areas (for example, the first area R1), the converted document format information generating unit 312 is the above-described difference document format generating unit 112 or The operation is the same as that of the divided document format generation unit 212. It is also possible to set the conversion region Rc including a region that is not in contact with other regions.
[0056]
Next, the conversion document format information generation unit 312 determines the division information for the conversion area Rc from the pseudo random number 131. The converted document format information generation unit 312 derives the converted document format information 333 from the division information and the document format information 33. The converted document format information 333 is transmitted to the digital watermark embedding unit 13 and the encryption unit 15.
[0057]
The watermark key generation unit 14 transmits the watermark key 34 to the digital watermark embedding unit 13 and the encryption unit 15.
[0058]
The digital watermark embedding unit 13 embeds a digital watermark only in a specific area in the original image 31 using the watermark key 34 based on the converted document format information 333 given from the converted document format information generating unit 312, and the original image 335 is generated. FIG. 15 shows a part of the original image 335. As shown in the figure, a rectangular first transform division region (first digital watermark embedding subregion) Rcd1, a second transform subregion (second digital watermark embedding subregion) Rcd2, and a third transform subregion (third digital watermark embedding). The sub-region Rcd3 is designated as a range for preventing image alteration in the second region R2, the third region R3, and the fourth region R4. Then, the same or different digital watermarks are embedded in the first conversion divided area Rcd1, the second conversion divided area Rcd2, and the third conversion divided area Rcd3.
[0059]
The first conversion divided region Rcd1, the second converted divided region Rcd2, and the third converted divided region Rcd3 are obtained by dividing the converted region Rc into two in the X axis direction and the Y axis direction, respectively. The division position changes according to the pseudo-random number generated in 111. Also, the number of areas need not be limited to three.
[0060]
The encryption unit 15 encrypts the converted document format information 333 and the watermark key 34 based on a predetermined algorithm, and generates the encrypted converted document format information 333enc and the encrypted watermark key 34enc.
[0061]
Original image output from the above digital watermark embedding apparatus 310 3 35, the encrypted conversion document format information 333enc and the encrypted watermark key 34enc are received by the digital watermark extracting apparatus 20.
[0062]
The decryption unit 22 provided in the digital watermark extraction apparatus 20 decrypts the encrypted converted document format information 333 enc and the encrypted watermark key 34 enc into the converted document format information 333 and the watermark key 34, respectively.
[0063]
The digital watermark extraction unit 21 extracts a digital watermark from the original image 335 using the converted document format information 333 and the watermark key 34. The digital watermark extracted here matches the digital watermark embedded in the original image 31 in the digital watermark embedding device 310 if the original image 335 has not been tampered with. That is, by checking the digital watermark extracted by the digital watermark extraction unit 21, it is determined whether the original image 335 has been tampered with.
[0064]
As described above, according to the image processing system 301 according to the third embodiment, a plurality of areas to be prevented from being tampered with are set as one conversion area, and this conversion area is further converted into a plurality of conversion division areas. They are divided and a digital watermark is embedded in each. Then, the size or shape of the conversion area and the division position of the conversion area when forming the conversion division area change according to the pseudo-random number generated by the random number generation unit 111. For this reason, even if the same watermark key 34 is applied to the same original image 31, if the user of the digital watermark embedding device 310, the digital watermark embedding device 310, or the use date / time is different, the digital watermark is embedded in the same range. Things are extremely rare. Since the digital watermark embedding range changes sequentially, it becomes extremely difficult to specify the range by a third party. Therefore, similarly to the first and second embodiments, it is difficult to analyze an algorithm related to digital watermark embedding / extraction.
[0065]
The preferred embodiments of the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to such embodiments. It will be obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.
[0066]
For example, by combining the embodiments, it becomes even more difficult to specify the embedding range of the digital watermark, and it becomes practically impossible to analyze the algorithm related to embedding / extracting the digital watermark.
[0067]
In each embodiment, the difference document format information 133, the divided document format information 233, the converted document format information 333, and the watermark key 34 are encrypted by the digital watermark embedding apparatuses 110, 210, 310, and then the digital watermark. It is transmitted to the extraction device 20. In addition, it is also preferable in terms of improving security to employ a method in which each information is not directly transmitted using a one-time password, for example.
[0068]
【The invention's effect】
As described above, according to the present invention, it becomes difficult for a third party to specify the embedding range of the digital watermark, and the analysis of the algorithm relating to the digital watermark embedding / extraction is prevented.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an image processing system according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram of difference information in the image processing system of FIG. 1;
FIG. 3 is an explanatory diagram of difference document format information in the image processing system of FIG. 1;
4 is an explanatory diagram of an original image in which a digital watermark is embedded by a digital watermark embedding apparatus provided in the image processing system of FIG. 1;
FIG. 5 is a block diagram showing a configuration of an image processing system according to a second embodiment of the present invention.
6 is an explanatory diagram of division information in the image processing system of FIG. 5;
7 is an explanatory diagram of divided document format information in the image processing system of FIG. 5;
FIG. 8 is an explanatory diagram of an original image in which a digital watermark is embedded by a digital watermark embedding device provided in the image processing system of FIG. 5;
FIG. 9 is an explanatory diagram of other division information in the image processing system of FIG. 5;
10 is an explanatory diagram of other divided document format information in the image processing system of FIG. 5. FIG.
11 is an explanatory diagram of another original image in which a digital watermark is embedded by the digital watermark embedding apparatus provided in the image processing system of FIG. 5;
FIG. 12 is a block diagram showing a configuration of an image processing system according to a third embodiment of the present invention.
13 is an explanatory diagram of an original image applied to the image processing system of FIG.
FIG. 14 is an explanatory diagram of an original image in which a conversion area is set by the digital watermark embedding apparatus provided in the image processing system of FIG.
15 is an explanatory diagram of an original image in which a digital watermark is embedded by a digital watermark embedding apparatus provided in the image processing system of FIG.
FIG. 16 is a block diagram illustrating a configuration of a conventional image processing system.
17 is an explanatory diagram of an original image applied to the image processing system of FIG.
18 is an explanatory diagram of a document format information table included in a document format database unit provided in the image processing system of FIG. 16;
FIG. 19 is an explanatory diagram of an original image in which a digital watermark is embedded by the digital watermark embedding apparatus provided in the image processing system of FIG. 16;
[Explanation of symbols]
11: Document identification unit
12: Document format database section
13: Digital watermark embedding unit
14: Watermark key generation unit
15: Cryptographic part
20: Digital watermark extraction apparatus
21: Digital watermark extraction unit
22: Decoding unit
31: Original image
32: Document information
33: Document format information
34: Watermark key
34enc: Encryption watermark key
101: Image processing system
110: Digital watermark embedding device
111: Random number generator
112: Difference document format generation unit
133: Difference document format information
133enc: Encrypted differential document format information
135: Original image
131: Pseudorandom number
201: Image processing system
210: Digital watermark embedding device
212: Divided document format information generation unit
233: Divided document format information
233enc: Encrypted divided document format information
235: Original image
301: Image processing system
310: Digital watermark embedding device
312: Conversion document format information generation unit
333: Conversion document format information
333enc: Encryption conversion document format information
335: Original image
R1: first region
R1s: first shift region
R1d1: first divided region
R1d2: second divided region
Rc: conversion area
Rcd1: first transformation divided region
Rcd2: second transformation division region
Rcd3: third transformation division region

Claims (6)

Choose al one or more tamper-proof region in the image, set the digital watermark embedding area including a part or all of the tamper-proof regions, embedding a digital watermark to the watermark embedding region, electrons An electronic watermark embedding device for generating a watermark embedded image,
A document identification unit that identifies the type of document by capturing features of the image;
A database unit that outputs document format information in accordance with the type of document identified by the document identification unit;
A document that sets a plurality of digital watermark embedding areas while sequentially changing at least one of position, size, or shape for one falsification preventing area based on the document format information output by the database unit A format information generator,
A digital watermark embedding unit that embeds a digital watermark in the plurality of digital watermark embedding regions set by the document format information generation unit;
An electronic watermark embedding device comprising: The digital watermark embedding device further includes a random number generator for generating a random number ,
The document format information generation unit uses the random number generated by the random number generation unit to sequentially change at least one of position, size, or shape for the one falsification prevention area. It is characterized by setting a digital watermark embedding area.
The digital watermark embedding apparatus according to claim 1. One or two or more alteration prevention areas are selected from the image, an electronic watermark embedding area including part or all of each of the anti-tampering areas is set, an electronic watermark is embedded in the electronic watermark embedding area, An electronic watermark embedding device for generating an embedded image,
A document format information generating unit that sets one digital watermark embedding area while sequentially changing at least one of position, size, or shape for a plurality of tamper-proof areas ;
A digital watermark embedding unit that embeds a digital watermark in the digital watermark embedding region set by the document format information generation unit;
An electronic watermark embedding device comprising: The digital watermark embedding device further includes a random number generator for generating a random number,
The document format information generation unit uses the random number generated by the random number generation unit to sequentially change at least one of a position, a size, or a shape with respect to the plurality of falsification prevention areas. 4. The digital watermark embedding apparatus according to claim 3, wherein an electronic watermark embedding area is set . The document format information generating unit divides the digital watermark embedding region of said one multiple watermark embedding sub-regions,
The digital watermark embedding unit embeds a digital watermark in each digital watermark embedding sub-region divided by the document format information generation unit ,
Electronic watermark embedding apparatus according to claim 3 or 4. The document format information generating unit, based on the random number generated in the random number generating unit, and determines a division position when forming the plurality of electronic watermark embedding subregion from the electronic watermark embedding region The digital watermark embedding apparatus according to claim 5.