JP2004040179A - Digital watermark embedding apparatus and digital watermark detecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein a date for generation and edit or the like of certificates cannot accurately be managed because falsification of an image is attained by the conventional technology. <P>SOLUTION: The digital watermark embedding apparatus for embedding a digital watermark to an image uses a date described in the image to produce a digital watermark and embeds the digital watermark to the image or uses any of the date when the image is formed, edited, stored or described to produce a digital watermark and embeds the digital watermark to the image. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a digital watermark embedding device that embeds a digital watermark in an image and a digital watermark detecting device that detects a digital watermark embedded in an image.
[0002]
[Prior art]
For example, in financial institutions, securities companies, insurance unions, and the like, an image of a certificate to be issued is captured by input means such as a scanner, and image data of the captured certificate is stored as original data in a management device such as a host computer.
[0003]
Here, the management of the original data is generally performed based on the date on which the certificate was created or the date on which the document was edited, such as printing the date on the issued certificate, imprinting a time stamp, Is stored in association with date (may include time). The date on which the certificate is issued will be described as being included in the date on which the certificate is created.
[0004]
[Problems to be solved by the invention]
However, it is possible to falsify an image with such a conventional method. For this reason, it was not possible to accurately manage the date on which the certificate was created or edited.
[0005]
It has also been difficult to manage whether the image data stored as original data is the original.
[0006]
[Means for Solving the Problems]
In order to solve the above problem, a digital watermark embedding device according to a first aspect of the present invention is characterized in that a digital watermark is generated using a date written on an image and the digital watermark is embedded in the image.
[0007]
Further, the digital watermark embedding device according to the second invention generates a digital watermark using any one of a date when the image is created or edited, and a date when the file is saved, and embeds the digital watermark in the image. It is characterized by.
[0008]
A digital watermark embedding device according to a third aspect of the present invention is characterized in that, in addition to the first or second aspect, the digital watermark is embedded so as to correspond to a date written on an image.
[0009]
A digital watermark embedding device according to a fourth aspect of the present invention, in addition to the first or second aspect, conceals a date written on an image and embeds the digital watermark in an image before or after concealment. Features.
[0010]
A digital watermark embedding apparatus according to a fifth aspect is characterized in that, in addition to any one of the first to fourth aspects, the digital watermark is embedded in an arbitrarily specified area.
[0011]
A digital watermark embedding device according to a sixth invention is characterized in that, in addition to any one of the first to fifth inventions, the digital watermark is generated by a fragile method or a semi-fragile method that is easily destroyed when tampered. I do.
[0012]
A digital watermark detection device according to a seventh aspect of the present invention provides an alarm to a user when the digital watermark embedded in an image is destroyed by the digital watermark embedding device according to the sixth aspect. Features.
[0013]
An electronic watermark detection device according to an eighth aspect extracts date information from an electronic watermark embedded in an image, and checks date information in a date described in the image or a date included in message data or a check included in the electronic watermark. It is characterized by comparing with a code.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
The digital watermark embedding device according to the present invention generates a digital watermark using a date written on an image and embeds the digital watermark in the image, or a date when the image is created or edited, and a date when the image is stored. A digital watermark is generated using any one of the above, and the digital watermark is embedded in an image.
[0015]
Further, the digital watermark detection device according to the present invention, when the digital watermark generated by the digital watermark embedding device according to the present invention is destroyed, notifies the user by issuing an alarm or is embedded in the image. Date information is extracted from the digital watermark, and the date information is compared with a date described in an image or a date included in message data or a check code included in the digital watermark. Note that the message data includes various types of information regarding the image data (for example, image format, digital watermarking scheme, digital watermarking key, compression scheme, encryption scheme, decryption key, etc.) and is attached to the image data.
[0016]
The present invention is not limited to the embodiments described below, and various applications and modifications are possible without departing from the gist of the present invention.
[0017]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the drawings are only schematically shown to the extent that the present invention can be understood. In addition, in each of the drawings, common elements are denoted by the same reference numerals, and description thereof is omitted.
[0018]
<First embodiment>
FIG. 1 is a diagram showing a configuration of a digital watermark embedding device according to the present invention, and FIG. 2 is a diagram showing a configuration of a digital watermark detecting device according to the present invention. It should be noted that the digital watermark embedding device and the digital watermark detection device can be integrated into one device.
[0019]
The digital watermark embedding device 1 shown in FIG. 1 includes an image input unit 11, an image memory 13, a digital watermark embedding unit 15, an output unit 17, a display unit 19, an image editing unit 21, an input unit 23, a control unit 25, and the like. Prepare.
[0020]
The image input unit 11 takes in image data into the device. As a specific configuration, for example, it is stored in an imaging unit such as an image scanner or a CCD camera, or a recording medium (floppy (registered trademark) disk, CD-ROM, DVD, IC card, or the like) or a storage device (hard disk or the like). It serves as reading means for reading image data from a file.
[0021]
The image memory 13 stores image data input from the image input unit 11 and image data created by the digital watermark embedding unit 15.
[0022]
The digital watermark embedding unit 15 embeds a digital watermark in the image data stored in the image memory 13. In the present embodiment, the attachment of the message data to the image data is also performed here. The image data subjected to such processing is output to the image memory 13 and stored therein.
[0023]
The output unit 17 outputs the image data stored in the image memory 13 to the outside.
[0024]
The display unit 19 displays image data stored in the image memory 13, image data edited by the image editing unit 21, various information input from the input unit 23, various information acquired from the outside, and the like.
[0025]
The image editing unit 21 performs various kinds of editing (for example, deleting a part of the image data, concealing the image data, or adding new image data to the image data).
[0026]
The input unit 23 receives input of various information from the user or receives input of various information from the outside. A specific configuration is, for example, a keyboard, a mouse, an I / O interface, and the like.
[0027]
The control unit 25 controls the entire apparatus.
[0028]
2 includes an image input unit 11, an image memory 13, an output unit 17, a display unit 19, an image editing unit 21, an input unit 23, a control unit 25, a digital watermark detection unit 27, and message data storage. A memory 29 and the like are provided.
[0029]
The digital watermark detection unit 27 detects and verifies the digital watermark of the image data stored in the image memory 13 and extracts the message data.
[0030]
The message data storage memory 29 stores the message data extracted by the digital watermark detection unit 27.
[0031]
In the present embodiment, a digital watermark is generated using date information (which may include a time), and the digital watermark is embedded so as to cover the date described in the image. At this time, it is preferable to embed the digital watermark on the entire surface of the image such that the digital watermark is applied to the date written on the image. Note that the digital watermark is embedded in an image by changing some luminance values and color palettes in pixels constituting the image using, for example, an encryption technique. The digital watermark detection device 2 can acquire predetermined information by detecting pixels in which a digital watermark is embedded, that is, by analyzing a pattern of changed pixels, thereby reading date information. Alternatively, tampering of the image can be detected.
[0032]
The operation of the digital watermark embedding device and the digital watermark detection device according to the present embodiment will be described below.
[0033]
FIG. 3 is a flowchart showing a procedure of digital watermark embedding and detection. 4A and 4B are diagrams showing digital watermark embedding, FIG. 4A shows an image obtained by the image input unit 11, and FIG. 4B shows an image with a digital watermark embedded therein. In the present embodiment, the image obtained by the image input unit 11 is used as an original image, and the original image data in which a digital watermark is embedded is used as the original data. Here, the digital watermark embedding device 1 is described as generating the digital watermark using the date described in the image. However, in addition to the above, various types of date information (for example, the date when the image is created, It is also possible to generate an electronic watermark by using the date of the data, the date stored in the image memory 13, the date obtained from the standard radio wave, the date of the system, and the like. The date on which the image was created or the date on which the image was edited is included in the message data input by the user from the input unit 23 or attached to the data of the original image.
[0034]
In step (hereinafter referred to as S) 11, the image input unit 11 of the digital watermark embedding device 1 acquires the original image 41 shown in FIG. 4A, for example, and outputs it to the image memory 13 as original image data. To be stored. In FIG. 4A, reference numeral 43 denotes date information written on the original image 41.
[0035]
Next, in S13, the digital watermark embedding unit 15 generates a digital watermark using the date information (which may include the time), and converts the digital watermark into the original image 41 as shown in FIG. The digital watermarked original image 45 as original data is generated by embedding so as to cover the date information 43 described in. In addition, message data is generated based on the date information and other information, and attached to the digital watermarked original image 45. The attachment is made in a format such as HTML. Then, the digital watermarked original image 45 that has undergone such processing is output to the image memory 13 and stored therein. In the present embodiment, the date information used for the digital watermark is any one of the date described in the original image 41, the date when the original image 41 was created, the date when it was edited, and the date when it was saved. The date on which the original image 41 was created, the date on which the original image 41 was edited, and the like are included in the message data input by the user from the input unit 23 or attached to the original image 45 with a digital watermark. The stored date is stored in the image memory 13 in association with the data of the original image 41 when the data is stored in the image memory 13.
[0036]
Thereafter, the user performs various processings on the digital watermarked original image 45 by the input unit 23, and the image data generated thereby is also stored in the image memory 13. In FIG. 4B, reference numeral 47 denotes digital watermarked date information described in the original image 41.
[0037]
In step S15, the output unit 17 outputs the digital watermarked original image 45 stored in the image memory 13 to the outside in response to a command from the user input from the input unit 23 or a request from the digital watermark detection device 2.
[0038]
In S31, the input unit 23 of the digital watermark detection device 2 acquires the digital watermarked original image 45 from the digital watermark embedding device 1, outputs it to the image memory 13, and stores it there.
[0039]
In S33, the digital watermark detection unit 27 extracts a digital watermark from the obtained digital watermarked image 45 according to a predetermined procedure. If the digital watermark cannot be extracted, an alarm is issued to the user to notify the user (for example, a warning is displayed on the display unit 19). Then, the digital watermark detection process ends.
[0040]
In S35, the digital watermark detection unit 27 verifies whether there is tampering. In the verification, for example, date information is extracted from the digital watermark, and the date information is compared with the date written in the digital watermarked original image 45 which is the original data or the date included in the message data or the check code included in the digital watermark. It does by doing.
[0041]
If there is tampering (that is, if the date information extracted from the digital watermark does not match the date written in the original image 45 with digital watermark or the date included in the message data or the check code included in the digital watermark, Is destroyed), an alarm is issued to notify the user (for example, a warning is displayed on the display unit 19). Then, the digital watermark detection process ends.
[0042]
If there is no tampering, the message data is extracted from the digital watermarked original image 45, output to the message data storage memory 29, and stored there.
[0043]
In S37, the control unit 25 acquires date information (may include time) from the message data storage memory 29. In this way, the digital watermark detection device 2 can acquire the date information of the image (here, the date described in the image) and manage it.
[0044]
At this time, the digital watermark detection unit 27 may solve the digital watermark based on the message data attached to the digital watermarked original image 45, and obtain the original image 41 without the digital watermark.
[0045]
In the present embodiment, the digital watermarked original image 45 in which the date information 43 written on the original image 41 and the digital watermark are inseparable is generated and used as the original data, so that it is difficult to falsify the original data. I do. Therefore, it is possible to accurately manage the date on which the certificate is created or edited.
[0046]
Also, in the event that either the digital watermarked original image 45 or the digital watermark is tampered with, the difference between the date information written on the digital watermarked original image 45 and the date information included in the digital watermark can be identified. In addition, it is possible to easily detect falsification of the original data. Therefore, it is easy to manage whether the image data stored as the original data is the original.
[0047]
<Second embodiment>
In the present embodiment, a part of the original image is painted or mosaiced with a different luminance / color from the original image in order to conceal personal information and company secret information existing in the original image. That is, in the present embodiment, a digital watermark is generated using date information. Then, the date written on the image is concealed, and a digital watermark is embedded in the concealed image. Alternatively, a digital watermark is embedded in the image, and the date written on the image is hidden from the image.
[0048]
In the present embodiment, the date information used for the digital watermark is any one of the date written on the image, the date when the image was created, the date edited, the date saved, and the like.
[0049]
Further, the digital watermark is generated by a fragile method or a semi-fragile method that is easily destroyed when tampered.
[0050]
The operation of the digital watermark embedding device and the digital watermark detection device according to the present embodiment will be described below. The configuration of the present embodiment is the same as that shown in FIGS. 1 and 2.
[0051]
FIG. 5 is a flowchart showing the procedure of digital watermark embedding and detection. 6A and 6B are diagrams showing digital watermark embedding / detection, FIG. 6A shows an image acquired by the image input unit 11, and FIG. 6B shows an image subjected to concealment processing. FIG. 6C shows an image in which a digital watermark is embedded (concealed).
[0052]
In S51, the image input unit 11 of the digital watermark embedding device 1 acquires, for example, the original image 41 shown in FIG. 6 (A), outputs it to the image memory 13 as original image data, and stores it there. Note that the date information 43 written on the original image 41 is information to be concealed.
[0053]
Next, in S53, as shown in FIG. 6B, the image editing unit 21 conceals the date information 43 from the original image 41 (for example, paints or deletes the corresponding portion), and performs the concealment processing. An image 49 is generated. In FIG. 6B, reference numeral 51 denotes an image of a hidden area (hereinafter, referred to as a hidden area image).
[0054]
Next, in step S55, the digital watermark embedding unit 15 generates a digital watermark using the date information (which may include the time) 43 and the position information (for example, coordinate values) where the date information 43 was present. It is embedded in the concealment-processed image 49 to generate a concealment-processed image 53 with a digital watermark. In addition, message data is generated based on date information, position information, and other information, and attached to the digital watermarked concealed image 53. Then, the digital watermarked concealment-processed image 53 having undergone such processing is output to the image memory 13 and stored therein. In the present embodiment, the date information used for the digital watermark is any one of the date described in the original image 41, the date when the original image 41 was created, the date when it was edited, and the date when it was saved. The date on which the original image 41 was created, the date on which the original image 41 was edited, and the like are included in the message data input by the user from the input unit 23 or attached to the concealed image 53 with the digital watermark. The stored date is stored in the image memory 13 in association with the data of the original image 41 when the data is stored in the image memory 13.
[0055]
Thereafter, the user performs various processes on the concealment-processed image 53 with the digital watermark by the input unit 23, and the image data generated by this process is also stored in the image memory 13. In FIG. 6C, reference numeral 55 denotes a concealed area image with a digital watermark.
[0056]
In step S57, the output unit 17 outputs the digital watermarked concealed image 53 stored in the image memory 13 to the outside in response to a command from the user input from the input unit 23 or a request from the digital watermark detection device 2. I do.
[0057]
In S71, the input unit 23 of the digital watermark detection device 2 acquires the concealment-processed image 53 with the digital watermark from the digital watermark embedding device 1, outputs it to the image memory 13, and stores it there.
[0058]
In S73, the digital watermark detection unit 27 extracts a digital watermark from the obtained digital watermarked concealed image 53 according to a predetermined procedure. If the digital watermark cannot be extracted, an alarm is issued to the user to notify the user (for example, a warning is displayed on the display unit 19). Then, the digital watermark detection process ends.
[0059]
In S75, the digital watermark detection unit 27 verifies whether or not there is tampering. In the verification, for example, date information is extracted from the digital watermark, and the date information is compared with the date included in the message data attached to the digital watermarked concealed image 53 that is the original data or the check code included in the digital watermark. It does by doing.
[0060]
When there is tampering (that is, when the date information extracted from the digital watermark does not match the date included in the message data attached to the concealed image 53 with the digital watermark or the check code included in the digital watermark, Is destroyed), an alarm is issued to notify the user (for example, a warning is displayed on the display unit 19). Then, the digital watermark detection process ends.
[0061]
If there is no tampering, the message data is extracted from the concealment-processed image 53 with digital watermark, output to the message data storage memory 29, and stored there. Further, by solving the digital watermark, the image of the date information 43 written on the original image 41 and the position information (for example, coordinate values) where the image of the date information 43 existed are acquired.
[0062]
In S77, the control unit 25 acquires date information (which may include time) from the message data storage memory 29, and obtains the creation date of the original data.
[0063]
In addition, the image editing unit 21 removes the digital watermark of the concealed image 53 with the digital watermark shown in FIG. 6C, and generates the concealed image 49 shown in FIG. 6B. Then, the image of the date information 43 described in the original image 41 acquired by the digital watermark detection unit 27 is replaced with the concealed area image 51 of the concealed image 49 shown in FIG. ) Is restored.
[0064]
In the present embodiment, the date on which the certificate is created or edited cannot be identified only by deciphering the date information 43 and decrypting the electronic watermark, so that the date can be accurately managed. Also, in the event that the concealment-processed image 53 with the digital watermark, which is the original data, has been tampered with, an electronic watermark of a method that is easily destroyed is used. it can. Therefore, it is easy to manage whether the image file stored as the original data is the original.
[0065]
<Third embodiment>
In the present embodiment, the digital watermarked date information image 47 is concealed from the digital watermarked original image 45 (see FIG. 4B) acquired in the first embodiment.
[0066]
FIG. 7 is a diagram showing digital watermark embedding / detection. 7A shows an image acquired by the image input unit 11, FIG. 7B shows an image in which a digital watermark is embedded, and FIG. 7C shows an image in which a digital watermark is embedded (concealment). 7 (A) and 7 (B) show the same processing steps as FIGS. 4 (A) and 4 (B).
[0067]
FIG. 7C shows that the digital watermarked date information 47 is concealed from the digital watermarked original image 45 to generate a digital watermarked concealed image 57.
[0068]
For concealment, for example, the digital watermark embedding unit 15 or the image editing unit 21 cuts out the digital watermarked date information 47 and encrypts the area based on a predetermined encryption method to generate a concealment area image 59 for replacement. This is performed by replacing the date information 47 with the digital watermarked date information 47. At this time, the digital watermark embedding unit 15 or the image editing unit 21 includes, in the message data, information for specifying the replacement position of the concealment area image 59 and information such as a key for decrypting (hereinafter, referred to as a decryption key). Then, it is attached to the digital watermarked concealment-processed image 57.
[0069]
Note that the digital watermark detection device 2 that detects a digital watermark from the concealment-processed image 57 with a digital watermark may perform the restoration from FIG. 7C to FIG. 7A in the following procedure.
[0070]
First, the digital watermark detection unit 27 extracts information specifying the replacement position of the concealment area image 59 and the decryption key from the message data attached to the concealment-processed image 57 with the digital watermark. Then, the concealment area image 59 is extracted from the concealment-processed image 57 with digital watermark, and the date information 47 with digital watermark is obtained from the concealment area image 59 using the decryption key. Then, the digital watermarked date information 47 is replaced with the concealed area image 59 of the digital watermarked concealment-processed image 57 to obtain the digital watermarked original image 45.
[0071]
Next, the digital watermark detecting unit 27 solves the digital watermark based on the message data attached to the digital watermarked original image 45, and acquires the original image 41 without the digital watermark.
[0072]
According to the present embodiment, a specific area can be concealed after a digital watermark is added to an original image.
[0073]
<Fourth embodiment>
In the present embodiment, a digital watermark is embedded in an arbitrarily specified area.
[0074]
8A and 8B are diagrams showing digital watermark embedding, FIG. 8A shows an image acquired by the image input unit 11, FIG. 8B shows an edited image, and FIG. C) shows an image in which a digital watermark is embedded.
[0075]
The image input unit 11 of the digital watermark embedding device 1 obtains, for example, an original image 61 shown in FIG. 8A, outputs it to the image memory 13 as original image data, and stores it there. Note that no date information is described in the original image 61, and the date information is embedded in the original image 61 as a digital watermark.
[0076]
Next, the image editing unit 21 specifies an area in which a digital watermark is to be embedded in the original image 61. Since the specified area (hereinafter, referred to as a specific area) is embedded with a digital watermark, security is particularly enhanced. Therefore, it is desirable that important information be described in the specific area. In the example shown in FIG. 8B, an example is shown in which an imprint image is newly added to the original image 61 and that image is used as a specific area. Hereinafter, an image obtained by adding a seal image to the original image 61 is referred to as an edited image. The image of the specified area is referred to as a specific area image. In FIG. 8B, reference numeral 63 denotes an edited image, and reference numeral 65 denotes a specific area image.
[0077]
Next, the digital watermark embedding unit 15 generates a digital watermark using date information (which may include the time), and embeds the digital watermark in the specific area 65 as shown in FIG. An edited image 67 with a digital watermark is generated. In addition, message data is generated based on the date information and other information, and attached to the edited image 67 with a digital watermark. Then, the edited image 67 with the digital watermark having been subjected to such processing is output to the image memory 13 and stored therein. In the present embodiment, the date information used for the digital watermark is any one of the date when the original image 61 was created, the date when it was edited, the date when it was saved, and the like. The date on which the original image 61 was created, the date on which the original image 61 was edited, and the like are input from the input unit 23 by the user. The stored date is stored in the image memory 13 in association with the data of the original image 41 when the data is stored in the image memory 13.
[0078]
Thereafter, the user performs various processes on the edited image 67 with the digital watermark by using the input unit 23, and the image data generated thereby is also stored in the image memory 13. In FIG. 8B, reference numeral 69 denotes a digital watermarked specific area image.
[0079]
The detection of a digital watermark is performed in the following procedure.
[0080]
First, the digital watermark detection unit 27 specifies the digital watermarked specific area image 69 from the message data attached to the edited image 67 with the digital watermark, and solves the digital watermark based on the message data. At this time, the digital watermark may be removed and the edited image 63 may be obtained.
[0081]
In this embodiment, a digital watermark can be embedded in an arbitrarily specified area.
[0082]
【The invention's effect】
The present invention described above has the following effects.
[0083]
That is, it is possible to accurately manage the date on which the certificate was created or edited. Alternatively, it can be easily managed that the image file stored as the original data is the original.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a digital watermark embedding device.
FIG. 2 is a diagram illustrating a configuration of a digital watermark detection device.
FIG. 3 is a flowchart illustrating a procedure of digital watermark embedding and detection.
FIG. 4 is a diagram showing digital watermark embedding.
FIG. 5 is a flowchart illustrating a procedure of digital watermark embedding and detection.
FIG. 6 is a diagram showing digital watermark embedding / detection.
FIG. 7 is a diagram showing digital watermark embedding / detection.
FIG. 8 is a diagram showing digital watermark embedding.
[Explanation of symbols]
1 Digital watermark embedding device
11 Image input section
13 Image memory
15 Digital watermark embedding part
17 Output section
19 Display
21 Image Editing Department
23 Input section
25 Control unit
27 Digital watermark detection unit
29 Message data storage memory

Claims (8)

In a digital watermark embedding device for embedding a digital watermark in an image,
A digital watermark embedding device, which generates a digital watermark using a date described in an image and embeds the digital watermark in the image. In a digital watermark embedding device for embedding a digital watermark in an image,
A digital watermark embedding device, which generates a digital watermark using one of a date when an image is created, edited, and a date when the image is stored, and embeds the digital watermark in the image. The digital watermark embedding device according to claim 1, wherein the digital watermark is embedded so as to cover a date written on an image. Hide the date on the image,
3. The digital watermark embedding apparatus according to claim 1, wherein the digital watermark is embedded in an image before or after concealment. The digital watermark embedding device according to claim 1, wherein the digital watermark is embedded in an arbitrarily specified area. The digital watermark embedding device according to any one of claims 1 to 5, wherein the digital watermark is generated by a fragile method or a semi-fragile method that is easily destroyed when tampered. In a digital watermark detection device that detects a digital watermark embedded in an image,
An electronic watermark detection device, wherein an alarm is issued to a user when the electronic watermark embedded in an image is destroyed by the electronic watermark embedding device according to claim 6. In a digital watermark detection device that detects a digital watermark embedded in an image,
Digital watermark detection, wherein date information is extracted from a digital watermark embedded in an image, and the date information is compared with a date written on the image or a date included in message data or a check code included in the digital watermark. apparatus.

Images