JP2002027223A - Data processing device and data controlling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data processing device which restricts sensitive influences on contents, while being capable of increasing the durability of watermarking information to accurately extract, and a data controlling system which can ensure the secrecy in the watermarking information to effectively perform the maintenance and control. SOLUTION: A data processing device 10 comprises: an input part 1 for inputting digital data; an image conversion part 2 for converting forms of the digital data; and a watermarking embedding part 3 for inserting watermarking information into the digital data of the converted form. The optimal watermarking information is fed in correspondence to a characteristic of the digital data. In a data controlling system which is constituted by the data processing device 10 and a controller 20 for information which provides a system for inserting the watermarking information, heterogeneous digital data (watermarking information) is embedded in correspondence to characteristics of an image such as character image, photograph image, net point image, or the like, so that the image quality is maintained, while a great amount of digital data can be embedded, and key information is controlled for maintenance, so that the secrecy of the embedded digital data can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Digital data such as digitized pictures, pictures, music, data, programs, etc.
When stored in a storage medium such as a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, or provided via a network such as a public line, the Internet, and Ethernet (registered trademark), The present invention relates to a data processing device and a data management system capable of effectively preventing such unauthorized use of digital data.

[0002]

2. Description of the Related Art With the improvement of digital processing technology, photographs,
Various contents including pictures, music, data, programs, and the like have been digitized and provided as products. By the way, in the case of analog data in which the original characteristics are degraded due to duplication, damage due to unauthorized duplication could be kept to a minimum, if any. In addition, even when digital data is distributed according to different standards, even if it is illegally copied, the damage can be limited to a limited range. However, if media is unified and recording and reproduction are easily performed even between different models, the effects of unauthorized duplication are expected to be widespread. In the case of electronic commerce on a network, since a physical distance barrier is eliminated, a copy may appear as soon as the original is provided. On the other hand, there is a problem that investigating the origin of a duplicate product involves much difficulty.

[0003] Such unauthorized duplication is prevented to protect the rights of the content owner or the author, etc.
In order to prevent crimes such as falsification of data and fictitious transactions between e-commerce transactions, a technique called digital watermarking has been studied. The electronic watermarking process inserts various information related to the content to be protected into the content to be protected, and the validity of the content can be determined based on the information. However, according to the digital watermarking process, a completely different kind of data (watermark information) is inserted into the digital data of the content, so that the original digital data of the content is mixed with noise that deteriorates the characteristics. This means that the effect appears in the content after the information is inserted. For example, in the case of image data, as image deterioration,
In the case of audio data, it may appear as noise.

[0004] In order to judge whether or not the duplication is illegal, the inserted watermark information must be accurately extracted. However, even if there is a memory failure or data communication failure, the extraction accuracy is maintained ( In order to achieve this, the amount of watermark information to be inserted must be secured to some extent. However, as the amount of watermark information increases, the effect on the content increases accordingly. In other words, there is a contradictory problem that it is better to reduce the amount of watermark information in order to reduce the influence on the content, while it is better to increase the amount of watermark information in order to maintain the durability of the watermark information.

As one method for solving such a problem of the digital watermarking process, digital data is decomposed into frequency components in advance by using a discrete wavelet transform, a discrete cosine transform, a discrete Fourier transform or the like, and a specific frequency In some cases, by inserting information into a component, the digital data itself is changed and information is inserted, but a change in the content represented by the digital data cannot be perceived by humans.

[0006]

However, irrespective of the characteristics of the content, when the information is embedded uniformly using the discrete wavelet transform or the like, the change of the content in which the information is embedded in the original is changed by humans. It has been found that it may be perceived. Further, if an unspecified person can grasp the watermark information, there is also a problem that unauthorized duplication becomes easy.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a data processing apparatus capable of accurately extracting the watermark information while increasing the robustness of the watermark information while suppressing the perceptual influence on the content.

Another object of the present invention is to provide a data management system which can secure confidentiality of watermark information and can effectively maintain and manage the watermark information.

[0009]

In order to achieve the above object, a data processing apparatus according to a first aspect of the present invention comprises an input unit for inputting digital data, a conversion unit for converting the form of the digital data, and Embedding means for inserting foreign digital data into the converted digital data is provided, and the foreign digital data is inserted in an optimum state according to the characteristics of the digital data.

According to a second aspect of the present invention, there is provided a data processing apparatus comprising: input means for inputting digital data; discriminating means for classifying the digital data in accordance with characteristics of the digital data; A plurality of conversion means for converting a form, and a plurality of embedding means for inserting foreign digital data into each of the digital data whose form has been converted, the plurality of embedding means being optimal according to the characteristics of each of the classified digital data. The method of inserting the heterogeneous digital data in a state is selected.

According to a third aspect of the present invention, there is provided a data management system for inputting digital data, converting means for converting the form of the digital data, and inserting foreign digital data into the converted digital data. A data processing device that inserts the heterogeneous digital data in an optimal state according to the characteristics of the digital data, and maintains and manages information about a key that defines a method for inserting the heterogeneous digital data. In a data management system including a management device, the management device provides information on the key when predetermined authentication information is input.

According to a fourth aspect of the present invention, there is provided a data management system comprising: input means for inputting digital data; discriminating means for classifying the digital data in accordance with characteristics of the digital data; A plurality of conversion means for converting the form of data, and a plurality of embedding means for inserting foreign digital data into each of the converted digital data, according to the characteristics of each of the classified digital data In the data management system, comprising: a data processing device that inserts the heterogeneous digital data in an optimal state; and a management device that maintains and manages information related to a key that defines a method of inserting the heterogeneous digital data. The apparatus provides information on the key when predetermined authentication information is input.

[0013]

According to a first aspect of the present invention, there is provided a data processing apparatus for inputting digital data, converting means for converting the form of the digital data, and inserting foreign digital data into the converted digital data. Since the heterogeneous digital data is inserted in an optimal state according to the characteristics of the digital data, for example, when the digital data is image data, a character image, a photographic image, a halftone image, etc. It is possible to embed a large amount of digital data while maintaining image quality by selecting a frequency that is difficult for humans to perceive according to the characteristics of the image and using it to embed foreign digital data (watermark information). Become. The same can be said for audio data and the like. Therefore, the digital data can be at least one of digital data such as audio data, text data, and program data, in addition to image data. Here, "converting the form of digital data" refers to, for example, decomposing data into a plurality of frequency components and bands, but is not limited thereto. Also, "heterogeneous data"
This means that the data has different properties from the digital data to be embedded. For example, when digital data to be embedded is image data such as a painting or CG, the data to be embedded may be image data representing, for example, a seal of a copyright holder.

Further, it is preferable that the input means can be connected to at least one of digital electronic devices such as a scanner, a digital still camera, a digital video camera, and a computer, and can input digital data from the digital electronic device. .

It is preferable that the conversion means performs one of conversion processes such as a discrete wavelet transform, a discrete cosine transform, and a discrete Fourier transform.

Further, it is preferable that the conversion means decomposes the digital data into a plurality of frequency components.

It is preferable that the conversion means decomposes the digital data into a plurality of frequency bands.

Further, it is preferable that the characteristic of the digital data is represented by a bias of a generation amount of a plurality of frequency components of the digital data decomposed by the conversion means.

It is preferable that the characteristic of the digital data is represented by a bias in the generation amount of a plurality of frequency bands of the digital data decomposed by the conversion means. The data processing device according to claim 4, wherein:

Further, unlike the digital data, the heterogeneous digital data includes information for managing the digital data such as a copyright holder name, a manufacturing date, a manufacturing location, and a serial number of the digital data, and the digital data. It is preferable that the information is at least one watermark information among information for protecting data from unauthorized use.

Preferably, the embedding of the watermark information is performed by using a secret key which is kept secret.

Further, it is preferable that the embedding of the watermark information is performed by using a public key which is made public.

According to a second aspect of the present invention, there is provided a data processing apparatus comprising: input means for inputting digital data; discriminating means for classifying the digital data according to characteristics of the digital data; A plurality of conversion means for converting a form, and a plurality of embedding means for inserting foreign digital data into each of the digital data whose form has been converted, the plurality of embedding means being optimal according to the characteristics of each of the classified digital data. Since the method of inserting the foreign digital data in the state is selected, for example, when the digital data is image data, a human perceives according to the characteristics of the image such as a character image, a photographic image, and a halftone image. By selecting difficult frequencies and using them to embed foreign digital data (watermark information), a large amount of It is possible to embed the digital data.

However, the digital data can be at least one of digital data such as audio data, text data, and program data, in addition to image data.

Further, it is preferable that the input means can be connected to at least one of digital electronic devices such as a scanner, a digital still camera, a digital video camera, and a computer, and can input digital data from the digital electronic device. .

It is preferable that the discrimination means classifies the digital data by reading a classification code in the digital data.

Furthermore, it is preferable that the discriminating means classifies the digital data by analyzing a data stream of the digital data.

It is preferable that the conversion means performs one of conversion processes such as a discrete wavelet transform, a discrete cosine transform, and a discrete Fourier transform.

Further, it is preferable that the conversion means decomposes the classified digital data into a plurality of frequency components.

It is preferable that the conversion means decomposes the classified digital data into a plurality of frequency bands.

Further, it is preferable that the characteristic of each of the classified digital data is represented by a bias of a generation amount of a plurality of frequency components of the digital data decomposed by each of the conversion means.

Preferably, the characteristic of each of the classified digital data is represented by a bias in a generation amount of a plurality of frequency bands of the digital data decomposed by the respective converting means.

Further, unlike the digital data, the heterogeneous digital data includes information for managing the digital data, such as a copyright holder name, a manufacturing date, a manufacturing location, and a serial number of the digital data, and the digital data. It is preferable that the information is at least one watermark information among information for protecting data from unauthorized use.

It is preferable that the watermark information is inserted based on a secret key kept secret in accordance with each of the classified digital data.

Further, it is preferable that the watermark information is inserted based on a public key that is published according to each of the classified digital data.

According to the third aspect of the data management system of the present invention, input means for inputting digital data, conversion means for converting the form of the digital data, and digital data different from the converted digital data A data processing device that inserts the heterogeneous digital data in an optimal state according to the characteristics of the digital data, and maintains information about a key that defines a method for inserting the heterogeneous digital data. In a data management system including a management device for managing, when the predetermined authentication information is input, the management device provides the information on the key. In the case of, the human perceives according to the characteristics of the image such as a character image, a photo image, and a dot image. By selecting a new frequency and using it to embed foreign digital data (watermark information), it is possible to embed a large amount of digital data while maintaining image quality, and also to maintain and manage information on the key. This ensures the confidentiality of the embedded digital data.

However, the digital data may be at least one of digital data such as audio data, text data, and program data in addition to image data.

Further, it is preferable that the input means can be connected to at least one of digital electronic devices such as a scanner, a digital still camera, a digital video camera, and a computer, and can input digital data from the digital electronic device. .

It is preferable that the conversion means performs one of conversion processes such as a discrete wavelet transform, a discrete cosine transform, and a discrete Fourier transform.

Further, it is preferable that the conversion means decomposes the digital data into a plurality of frequency components.

It is preferable that the conversion means decomposes the digital data into a plurality of frequency bands.

Further, it is preferable that the characteristic of the digital data is represented by a bias in a generation amount of a plurality of frequency components of the digital data decomposed by the conversion means. 29. The data management system according to claim 28, wherein:

It is preferable that the characteristic of the digital data is represented by a bias in a generation amount of a plurality of frequency bands of the digital data decomposed by the conversion means.

Further, unlike the digital data, the heterogeneous digital data includes information for managing the digital data such as a copyright holder name, a manufacturing date, a manufacturing location, and a serial number of the digital data, and the digital data. It is preferable that the information is at least one watermark information among information for protecting data from unauthorized use.

Preferably, the key is a secret key kept secret.

Further, it is preferable that there are a plurality of the secret keys, and the secret keys be stored on independently separated databases.

Further, it is preferable that the key is a public key that is made public.

Further, it is preferable that there are a plurality of the public keys, and the public keys be stored in an independently separated database.

According to a fourth aspect of the present invention, there is provided a data management system comprising: input means for inputting digital data; discriminating means for classifying the digital data in accordance with characteristics of the digital data; A plurality of conversion means for converting the form of data, and a plurality of embedding means for inserting foreign digital data into each of the converted digital data, according to the characteristics of each of the classified digital data In the data management system, comprising: a data processing device that inserts the heterogeneous digital data in an optimal state; and a management device that maintains and manages information related to a key that defines a method of inserting the heterogeneous digital data. The device provides information on the key when predetermined authentication information is input, so that the data For example, when digital data is image data, a frequency that is difficult for humans to perceive is selected in accordance with image characteristics such as a character image, a photographic image, and a halftone dot image. By embedding data (watermark information), it is possible to embed a large amount of digital data while maintaining image quality. In addition, by maintaining and managing information related to the key, confidentiality of the embedded digital data can be ensured. .

However, the digital data may be at least one of digital data such as audio data, text data, and program data in addition to image data.

Further, it is preferable that the input means can be connected to at least one of digital electronic devices such as a scanner, a digital still camera, a digital video camera, and a computer, and can input digital data from the digital electronic device. .

It is preferable that the discrimination means classifies the digital data by reading a classification code in the digital data.

Further, it is preferable that the discriminating means classifies the digital data by analyzing a data stream of the digital data.

Preferably, the conversion means performs one of conversion processes such as discrete wavelet transform, discrete cosine transform, and discrete Fourier transform.

Further, it is preferable that the conversion means decomposes the classified digital data into a plurality of frequency components.

It is preferable that the conversion means decomposes the classified digital data into a plurality of frequency bands.

Further, it is preferable that the characteristic of each of the classified digital data is represented by a bias of a generation amount of a plurality of frequency components of the digital data decomposed by each of the conversion means.

It is preferable that the characteristic of each of the classified digital data is represented by a bias in a generation amount of a plurality of frequency bands of the digital data decomposed by each of the conversion means.

Further, unlike the digital data, the heterogeneous digital data includes information for managing the digital data such as a copyright holder name, a manufacturing date, a manufacturing location, and a serial number of the digital data, and the digital data. It is preferable that the information is at least one watermark information among information for protecting data from unauthorized use.

Further, it is preferable that the watermark information is inserted based on a secret key kept secret in accordance with each of the classified digital data.

Further, it is preferable that there are a plurality of the secret keys, and the secret keys be stored on independently separated databases.

Further, it is preferable that the watermark information is inserted based on a public key that has been released according to each of the classified digital data.

Further, it is preferable that there are a plurality of the public keys, and the public keys be stored in an independently separated database.

[0064]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a data processing apparatus and a data management system according to the present invention will be described. FIG. 1 is a configuration diagram schematically showing a data processing device according to a first embodiment of the present invention. With reference to FIG. 1, the processing function of each unit will be described.

An input unit 1 (hereinafter the same), which is an input means,
It has a function of connecting to digital electronic devices such as a scanner, a digital still camera, a digital video camera, and a computer to input image data into the device. here,
The case of a scanner using a CCD will be described, but the input unit 1 is not limited to this.

The input unit 1 irradiates a document with light from a light source (not shown) and converts the reflected light into an electric signal by a solid-state image sensor (CCD). The brightness of the reflected light corresponds to the amount of charge stored in the CCD. An analog electric signal obtained by photoelectric conversion is subjected to analog / digital conversion in the input unit 1. The digitized image data is multi-valued image data having a predetermined number of bits.
The input unit 1 is not limited to the one that performs photoelectric conversion. For example, when image data is transmitted via a network such as a public line, the Internet, or Ethernet, the input unit 1
Includes an interface suitable for each network and capable of acquiring such image data.

When image data is stored in various storage media, floppy disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, etc., the input unit 1 is a reading device suitable for each storage medium. In addition, those that can acquire such image data are also included. In any case, the input image data is multi-valued image data having a predetermined number of bits.

If one pixel is represented by 8-bit information, it can be handled as image data of 256 gradations from 0 to 255 steps. By using three equivalent image data sequences, for example, red image data, green image data, and blue image data, multi-valued color image data can be formed. By providing three functions (red, green, and blue), multi-valued color image data can be input. In this embodiment, each pixel is composed of 8 bits and 2 bits.
It is assumed that self-black image data capable of expressing 56 gradations is input.

Image conversion unit 2 as conversion means (the same applies hereinafter)
Has a function of decomposing input image data into a plurality of frequency components. As a method of decomposing image data into a plurality of frequency components, a discrete wavelet transform, a discrete cosine transform, a discrete Fourier transform, and the like are known. The multi-valued image data is decomposed into a plurality of frequency components by each conversion. The amount of each frequency component decomposed depending on the type or feature of the image is biased. Image data forming characters and line drawings has relatively many high frequency component signals. Conversely, image data for forming a film photograph or the like has many low frequency component signals. Further, image data forming a halftone dot has an extremely large number of specific frequency components. That is, the image data is characterized by frequency components that are decomposed depending on the type and characteristic of the image.

In the digital watermarking process, when watermark information, which is digital data different from image data, including, for example, a copyright holder, is inserted, deterioration of the image due to the insertion of the watermark information must be prevented. No. By inserting watermark information into a small number of frequency components, the effect on the image can be suppressed. For example, in the case of image data in which gradation is regarded as important such as a film photograph,
The effect on human vision can be reduced by inserting watermark information only into high frequency components.

However, embedding the same watermark information in character image data or halftone image data, even when the watermark information is embedded in, for example, photographic image data, has little effect, may greatly reduce the image quality. .

Therefore, in the present embodiment, for example, a worker looks at a document and determines whether the data is photographic image data, character image data, or halftone image data, and inputs the data to obtain a watermark. The embedding unit 3 selects an appropriate public key PK and embeds watermark information.

More specifically, the watermark embedding unit 3 receives a plurality of frequency components decomposed by the image conversion unit 2, a public key PK, and watermark information I. The watermark embedding unit 3 has a function of determining an appropriate frequency component according to image data according to the public key PK and inserting watermark information using the frequency component.

The public key PK indicates information necessary for inserting the watermark information I into the image data. Since the public key PK is publicly known, its detailed description is omitted. A component, a place to be inserted, an amount to be inserted, and the like are indicated, and a method of inserting watermark information into image data is specified. The method specified by the public key PK is suitable for enhancing the resistance of the watermark information without visually affecting the image.

The tolerance of the watermark information is a change in the watermark information accompanying a change in the image data. Even if it is digital data, it is known that image data may change (delete) to some extent due to defective memory or communication, but even in such a case, it is desirable that the inserted watermark information be accurately extracted. It is.

In order to maintain high resistance to such a change in image data, a simple solution is to increase the amount of watermark information to be inserted (for example, to repeatedly embed the same watermark information). However, simply increasing the amount does not greatly affect the image data and does not cause visual image deterioration. As described above, the prevention of image deterioration and the enhancement of durability have a contradictory relationship. According to the present embodiment, such a problem can be appropriately solved or alleviated.

The public key PK indicates a method of preventing the image from deteriorating while maintaining the resistance of the watermark information. Public key P
K is open to the public. For example, it is open to an unspecified number of people on a home page opened on the Internet, etc., or is only open to a specific group by accessing a key management authority for the purpose of managing public keys. . Watermark information is information inserted into image data. In many cases, it is desired that the watermark information is information unique to the image and inserted in order to maintain the value of the image. In this case, for example, the copyright owner name, date of manufacture, manufacturing location, serial number, etc. Conceivable. Using the public key PK,
It protects the rights of copyright owners, prevents unauthorized duplication, and can be useful in criminal investigations.

The processing operation of the data processing apparatus according to the present embodiment will be described more specifically. From the input unit 1, multi-valued image data having a predetermined number of bits is input. In this embodiment, black-and-white image data composed of 8 bits per pixel is used.

The input image data is input to the image converter 2. The multi-valued image data in the image converter 2 is
Decomposed into multiple frequency components. As described above, the frequency components to be decomposed are characteristic according to the type of image data.

The image data decomposed into frequency components is input to the watermark embedding unit 3. The public key PK and the watermark information I are input to the watermark embedding unit 3 (embedding means). The watermark embedding unit 3 inserts the watermark information I into the image data according to the public key PK.
The public key PK indicates the frequency component in which the watermark information is to be inserted, the place where the watermark information is to be inserted, the amount to be inserted, and the like. The watermark embedding unit 3 performs embedding in compliance with the method specified by the public key PK.

The embedding process is performed by assigning the lower few bits of the decomposed image data of each frequency component to watermark information. In accordance with the embedding method defined by the public key PK, the watermark embedding unit 3 inserts the watermark information of a specific insertion amount into a specific insertion location of the frequency component of the selected image data.

The image data has a characteristic in a frequency component decomposed according to the type of the image. A frequency component that does not visually affect the image by inserting the watermark information into the image data is selected. A specific place for suppressing the influence on the peripheral image in the selected frequency component is selected. A particular location in a particular frequency component that has the least effect on the image is selected, and the lower few bits of the image data are allocated for inserting watermark information.

Even at a specific location in a specific frequency component where the effect on the image is minimized, if the amount of watermark information to be inserted is large, the effect on the image is large, and visual degradation of the image is ignored. become unable. In consideration of the influence on the image, the smaller the amount of watermark information to be embedded, the better.

There is a risk that image data will always change due to external influences. When communication is performed on a network, the image data transmitted from the transmission side cannot always be accurately received at the reception side because the communication apparatus is affected by the communication device, the communication environment, the communication state, and the like. Further, the same image data cannot always be read from the image data stored in the storage medium due to the influence of defects in the storage medium itself, deterioration over time, a failure of a reading device of the storage medium, and the like. Therefore, it is necessary to take a countermeasure for the image data as it changes.

That is, since the watermark information inserted into the image data is also digital data and is affected by the outside, the watermark information may be changed in the same manner as the image data. As a method of accurately extracting the inserted watermark information, an error correction encoding process or the like for correcting data changed by the method described below is known. Correct watermark information can be extracted. A simpler method is to simply increase the amount of watermark information to be inserted. Even if a part of the watermark information changes, if more watermark information can be extracted, correct watermark information can be recognized by majority rule. It is also possible to predict and correct the changed watermark information from the surrounding watermark information. In order to increase the resistance to accurately extract the watermark information against the influence from the outside, the larger the amount of the watermark information to be inserted, the better.

Thus, the amount of watermark information to be inserted is smaller when the influence on the image is taken into account, while it is larger when the tolerance of the watermark information is taken into account. This problem can be solved by following the method specified in the public key PK. The effect on the image can be suppressed and the resistance of the watermark information can be maintained. The watermark embedding unit selects an appropriate frequency component of the image data according to the public key, and inserts an appropriate amount of watermark information at an appropriate location. Thereby, the resistance of the watermark information is maintained while suppressing the influence on the image and preventing the visual deterioration.

The image data into which the watermark information has been inserted is input to the output unit 4. The output unit 4 has a function of outputting image data in which watermark information is embedded to the outside.
It is assumed that the output unit 4 is connected to the outside in various forms. For example, when connected to various networks, public lines, the Internet, Ethernet, and the like, the output unit 4 corresponds to an interface suitable for each network. Also, when connected to various storage media, floppy disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, etc.,
The output unit 4 corresponds to a writing device suitable for each storage medium.

The image data in which the watermark information is embedded is output to the outside in various forms connected to the output unit 4. For example, if the output unit 4 is connected to a network, the image data is transmitted via the network according to a network protocol. Alternatively, if the output unit 4 includes a writing device, the image data is stored in a storage medium after being converted into an appropriate format. The storage medium in which the image data in which the watermark information is embedded is stored is removable from the data processing device. If the storage medium is input to various devices having an appropriate reading device, the various devices can store the watermark stored in the storage medium. Image data in which information is embedded can be read.

According to the embodiment described below, it is possible to increase the efficiency of watermark information embedding processing, that is, to enable accurate extraction of watermark information while preventing visual image deterioration. FIG. 2 is a configuration diagram schematically showing a data processing device according to the second embodiment of the present invention.

The data processing apparatus according to the present embodiment includes an input unit 1, an area discriminating unit 5, a plurality of image conversion units 2A to 2C, a plurality of watermark embeddings each of which inputs watermark information I and public keys PPK, CPK, and NPK. Parts 3A to 3C, synthesis part 6,
And an output unit 4.

The processing operation of the data processing device according to the present embodiment will be described. From the input unit 1, multi-valued image data having a predetermined number of bits is input. In the present embodiment, black-and-white image data composed of 8 bits per pixel is used.
Here, the image data photoelectrically converted by the input unit 1 is
As shown in FIG. 3, the photographic image data A
And character image data B and halftone image data C are mixed.

The image data input from the input unit 1 is first input to the area determination unit 5. In an area discriminating unit 5 (hereinafter the same) as discriminating means, the input image data is classified according to its type or characteristics. Area determination unit 5
For example, the entire screen is determined to be photographic image data, or in the case shown in FIG. 3, the screen is divided into a plurality of areas.
It can be determined that photographic image data, character image data for region B, and dot image data for region C.

Various methods for classifying image data have already been introduced. For example, a classification code is included in image data, and determination is performed according to the classification code. In such a case, the area determination unit 5 can read the classification code inserted in the header of the data, for example, and classify the subsequent image data. In addition, there is a method of classifying the image data into a predetermined image type by analyzing a characteristic of a change in the image data (seeing a data stream). Various algorithms for analyzing image data and classifying images have been introduced. The area determination unit 5 divides the image data into blocks of M pixels vertically and N pixels horizontally (M and N are arbitrary numbers), and classifies the image for each block. In the present embodiment, the image that can be distinguished is a photographic image having a characteristic of continuous tone represented by a photograph or a painting, a character image having a characteristic of an edge component represented by a character or a drawing,
The halftone image represented by a photograph or the like on a newspaper is three types of halftone images having characteristics.

The classified image blocks are input to image conversion units 2A to 2C prepared for various image blocks in advance. That is, the image blocks classified into the photographic images (region A in FIG. 3) are transmitted to the photographic image conversion unit 2A, and the image blocks classified into the character images (region B in FIG. 3) are transmitted to the character image conversion unit 2B. Image blocks classified into images (Fig. 3
Are input to the dot image conversion unit 2C. In each of the image conversion units 2A to 2C, the multi-valued image data is decomposed into a plurality of frequency components.

The frequency components to be decomposed are characteristic according to the type of image data. A photographic image has many low frequency component signals. Conversely, a character image has many high frequency component signals. The frequency components that are decomposed in accordance with the type and characteristics of the image are biased. As a result of the processing performed only on a small number of frequency components, the obtained image has no visual effect. For example, even if the signal of the high-frequency component decomposed from the photographic image is artificially changed, the effect is not seen on the image obtained by synthesizing the frequency components again. Further, even if the signal of the low frequency component decomposed from the character image is artificially changed, the effect is not seen on the image obtained by synthesizing the frequency components again. In the case of a dot image, a characteristic frequency component is decomposed by the number of lines forming the dot. Only certain frequency components are significantly more detected. The processing performed on a small number of frequency components does not affect the recombined image.

Each image data decomposed into frequency components is input to each of the watermark embedding units 3A to 3C. The watermark embedding units 3A to 3C include a public key,
Watermark information I is input. The watermark embedding units 3A to 3C insert the watermark information I into the image data according to the public key. There are a plurality of different types of public keys corresponding to the types and characteristics of images.
In 3C, a public key suitable for the image data to be processed is used. That is, the watermark embedding unit 3A that processes the frequency components decomposed from the photographic image employs the photographic image public key PPK that defines the embedding method corresponding to the photographic image. Similarly, the watermark embedding unit 3B that processes the frequency component decomposed from the character image processes the character image public key CPK that specifies the embedding method corresponding to the character image, and processes the frequency component decomposed from the halftone image. The watermark embedding unit 3C employs a dot image public key NPK that defines an embedding method corresponding to the dot image. For each public key:
The frequency component to insert the watermark information I, the insertion location, the insertion amount, and the like are shown, and each of the watermark embedding units 3A to 3C observes the method defined by the adopted public key.

In the embedding process by the watermark embedding units 3A to 3C, the lower few bits of the image data of each decomposed frequency component are assigned to the watermark information I. According to the embedding method defined by the public key, the watermark information of a specific insertion amount is inserted into a specific insertion location of the frequency component of the selected image data.

The image data has a characteristic in frequency components that are decomposed depending on the type of image. A frequency component that does not visually affect the image by inserting the watermark information I into the image data is selected. A specific place for suppressing the influence on the peripheral image in the selected frequency component is selected. A particular location in a particular frequency component that has a minimal effect on the image is selected and the lower few bits of the image data are allocated for inserting watermark information.

Even at a specific location in a specific frequency component where the effect on the image is minimized, if the amount of watermark information to be inserted is large, the effect on the image will be large, and visual image degradation will be ignored. become unable. In consideration of the influence on the image, the smaller the amount of watermark information to be embedded, the better.

There is a risk that image data will always change due to external influences. When communication is performed on a network, the image data transmitted from the transmission side cannot always be accurately received at the reception side because the communication apparatus is affected by the communication device, the communication environment, the communication state, and the like. Further, the same image data cannot always be read from the image data stored in the storage medium due to the influence of defects in the storage medium itself, deterioration over time, a failure of a reading device of the storage medium, and the like. Therefore, it is necessary to take a countermeasure for the image data as it changes.

That is, since the watermark information inserted into the image data is also digital data and is affected by external influences, the watermark information may be changed similarly to the image data. As a method of accurately extracting the inserted watermark information, an error correction encoding process or the like for correcting data changed by the method described below is known. Correct watermark information can be extracted. A simpler method is to simply increase the amount of watermark information to be inserted. Even if a part of the watermark information changes, if more watermark information can be extracted, correct watermark information can be recognized by majority rule. It is also possible to predict and correct the changed watermark information from the surrounding watermark information. In order to increase the resistance to accurately extract the watermark information against the influence from the outside, the larger the amount of the watermark information to be inserted, the better.

Thus, the amount of watermark information to be inserted is smaller when the influence on the image is taken into account, while it is larger when the tolerance of the watermark information is taken into account. This problem can be solved by following the method specified in the public key. The effect on the image can be suppressed and the resistance of the watermark information can be maintained. The watermark embedding unit selects an appropriate frequency component of the image data according to the public key, and inserts an appropriate amount of watermark information at an appropriate location. Thereby, the resistance of the watermark information is maintained while suppressing the influence on the image and preventing the visual deterioration.

The image data block into which the watermark information generated in each of the watermark embedding units 3A to 3C is inserted is input to the synthesizing unit 6. The synthesizing unit 6 rearranges each image data block on one screen, and
Generate image data for the screen.

As described above, the input image data is classified according to its type and characteristics, and the watermark information is embedded according to the public key defining the optimum embedding method for each image data. This makes it possible to perform more effective embedding processing of watermark information than embedding with a type of public key.

The image data into which the watermark information I has been inserted is input to the output unit 4. The output unit 4 has a function of outputting image data to the outside. It is assumed that the output unit 4 is connected to the outside in various forms. For example, when connected to various networks, public lines, the Internet, Ethernet, and the like, the output unit 4 corresponds to an interface suitable for each network.
When connected to various storage media, floppy disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, and the like, the output unit 4 corresponds to a writing device suitable for each storage medium.

The image data in which the watermark information is embedded is output to the outside in various forms connected to the output unit 4. If the output unit 4 is connected to a network, it is transmitted via the network according to the network protocol. After being converted into an appropriate format by various writing devices, it is stored in a storage medium. The storage medium storing the image data in which the watermark information is embedded is removable with respect to the data processing device, and if the storage medium is input to various devices having an appropriate reading device, the various devices are stored in the storage medium. Image data can be read out.

In the embodiment described below, a data management system including the above-described data processing device is configured.
FIG. 4 is a configuration diagram illustrating an outline of a data management system using the third embodiment.

In FIG. 4, the data processing apparatus 10 and the management apparatus 20 of the key management station constituting the data management system are connected to various networks, that is, public lines, the Internet, Ethernet, etc., and are mutually accessible. It is. The data processing device 10 can request the key management station to provide information. The key management authority,
For example, based on authentication information such as an ID number and a password, the requester confirms the validity of the requester and responds to the requested information.

The key management station operates the system while managing and providing the information by the management device 20 for maintaining and managing the information on the key. The participants in the system are limited to those who have the right to participate, and the key management authority authenticates and verifies the participants. Those who wish to participate in the system apply to the key management office. The key management authority authenticates the applicant if the validity of the applicant is confirmed. Only applicants who have been authenticated by the key management authority may be entitled to participate (along with a predetermined ID number, password, etc.) and become participants in the formal system. The management device 20 stores the key of the applicant in association with the ID number and the password.

The participant of the system can request the key management station to provide information as needed. The key management station checks the validity of the requester of the information provision from the ID number and the password. Specifically, when a person requesting information provision inputs an ID number or a password to the management device 20, the requester is verified, and if there is no error, a corresponding key is transmitted. ing. That is, if the requester of information provision is verified, the key management station responds to the request for provision of information. Thus, the key management station authenticates and verifies the participants. Further, the key management station can manage information on keys. Information about the key
It is confidential and is not disclosed for unauthorized access. Also, by guaranteeing the validity of the information, profits can be provided to system participants. The key authority plays a role in maintaining the security and reliability of the entire system by authenticating and verifying the participants and ensuring the validity of the information.

The data processing device 10 for performing the watermark embedding process is used in a data management system via a key management station. The data processing device 10 is the management device 2 of the key management station.
0 has a function of requesting the provision of a public key via a network. The management device 20 of the key management station checks the public key provision request. If verified, the management device 20 of the key management station discloses the public key to the data processing device 10.

As described above, the data processing device 10
Using the public key provided from the management device 20, the watermark embedding unit 3A to 3C performs a watermark embedding process. As described in the second embodiment of the present invention, when an optimal public key is used according to the type and characteristics of image data, the data processing device 10
0 receives a plurality of public keys. The data processing device 10 performs the watermark embedding process in the watermark embedding unit using the provided plurality of public keys for the respective optimum image data. As shown in FIG. 3, when one screen is subjected to watermark embedding processing using an optimal public key for each constituent image block, one screen is subjected to watermark embedding processing using a single public key. More effective watermark embedding processing can be performed.

The management device 20 of the key management station monitors unauthorized access to information, writing of information, reading of information, and obstruction of access to legitimate system participants in order to maintain the reliability of information management. , They must take appropriate measures. It is preferable that countermeasures including criminal complaints can be carried out with respect to persons who have made unauthorized access by using a unique means inside the key management bureau to investigate and find out. Nevertheless, the technology for unauthorized access to information will become more sophisticated as technology advances,
You must always take defensive measures. Various methods are already known as defense measures, such as encryption processing including encoding. There is a simpler method for separating and managing information.

It is conceivable that even if certain information is leaked, it is meaningless as information unless all information is leaked. For example, by storing a plurality of public keys on different databases constructed on different hard disks of the management device 20, the security of the data management system can be improved against hackers and the like.

It is preferable that the key management station has one private secret key for one public key and is managed in the same manner as the public key. The private key is used when extracting the watermark information inserted by the corresponding public key.

In the above-described embodiment, the public key is used to insert the watermark information into the image data. However, a common secret key may be used similarly. For example, if only a plurality of persons belonging to the same group can use the common secret key, any person can insert and extract the watermark information. ,
Neither insertion nor extraction of watermark information can be performed, thereby preventing unauthorized duplication of data.

[0117]

According to the present invention, an effective digital watermarking process can be performed by performing a digital watermarking process in accordance with key information defining an optimal digital watermarking process according to the characteristics of digital data. The key information is maintained and managed by the management device of the key management station, so that the security of the digital watermarking process is maintained.

According to the present invention, effective digital watermarking is performed by classifying digital data according to the characteristics of the digital data and performing digital watermarking processing in accordance with key information that defines optimal digital watermarking processing for each digital data. Watermarking can now be performed. The security of the digital watermarking process is maintained by separately maintaining and managing a plurality of pieces of key information on different databases of a key management station.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a data processing device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram schematically showing a data processing device according to a second embodiment;

FIG. 3 is a diagram illustrating an example of a document read by a data processing device.

FIG. 4 is a configuration diagram schematically showing a data management system according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input part 2 Image conversion part 3 Watermark embedding part 4 Output part 5 Area discriminating part 6 Synthesis part

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Claims (52)

[Claims] An input means for inputting digital data,
A conversion unit for converting a form of the digital data; and an embedding unit for inserting foreign digital data into the digital data whose form has been converted, wherein the foreign digital data is in an optimal state according to the characteristics of the digital data. A data processing device, wherein 2. The data processing apparatus according to claim 1, wherein the digital data is at least one of digital data such as image data, audio data, text data, and program data. 3. The input means is connectable to at least one of digital electronic devices such as a scanner, a digital still camera, a digital video camera, and a computer, and can input digital data from the digital electronic device. The data processing device according to claim 1 or 2, wherein 4. The data processing apparatus according to claim 1, wherein the conversion unit performs one of conversion processes such as a discrete wavelet transform, a discrete cosine transform, and a discrete Fourier transform. . 5. The apparatus according to claim 4, wherein said conversion means decomposes the digital data into a plurality of frequency components.
A data processing device according to claim 1. 6. The digital camera according to claim 4, wherein the converting unit decomposes the digital data into a plurality of frequency bands.
A data processing device according to claim 1. 7. The data processing apparatus according to claim 4, wherein the characteristic of the digital data is represented by a bias in a generation amount of a plurality of frequency components of the digital data decomposed by the conversion unit. . 8. The data processing apparatus according to claim 4, wherein the characteristic of the digital data is represented by a bias in a generation amount of a plurality of frequency bands of the digital data decomposed by the conversion means. . 9. The different kind of digital data is different from the digital data, and information for managing the digital data such as a copyright holder name, a manufacturing date, a manufacturing place, and a serial number of the digital data, and the digital data. 7. The data processing device according to claim 1, wherein the data processing device is at least one of watermark information among information for protecting data from unauthorized use. 10. The data processing apparatus according to claim 1, wherein the embedding of the watermark information is performed using a secret key that is kept secret. 11. The data processing apparatus according to claim 1, wherein the embedding of the watermark information is performed using a public key that has been made public. 12. Input means for inputting digital data, discriminating means for classifying the digital data according to characteristics of the digital data, and a plurality of converting means for converting the form of each of the classified digital data. A plurality of embedding means for inserting foreign digital data into each of the digital data whose form has been converted,
A data processing apparatus, wherein a method of inserting the heterogeneous digital data in an optimal state is selected according to characteristics of each of the classified digital data. 13. The digital data includes image data,
13. The data processing apparatus according to claim 12, wherein the data is at least one of digital data such as voice data, text data, and program data. 14. The input means is connectable to at least one of digital electronic devices such as a scanner, a digital still camera, a digital video camera, and a computer, and can input digital data from the digital electronic device. The data processing device according to claim 12, wherein 15. The data processing apparatus according to claim 12, wherein the determination unit classifies the digital data by reading a classification code included in the digital data. 16. The data processing apparatus according to claim 12, wherein said determining means classifies said digital data by analyzing a data stream of said digital data. 17. The apparatus according to claim 12, wherein said conversion means performs one of conversion processes such as a discrete wavelet transform, a discrete cosine transform, and a discrete Fourier transform.
7. The data processing device according to any one of 6. 18. The data processing apparatus according to claim 17, wherein the conversion unit decomposes the classified digital data into a plurality of frequency components. 19. The data processing apparatus according to claim 17, wherein the conversion unit decomposes the classified digital data into a plurality of frequency bands. 20. The characteristic of each of the classified digital data is represented by a bias of a generation amount of a plurality of frequency components of the digital data decomposed by each of the conversion units. 18. The data processing device according to item 17. 21. The feature of each of the classified digital data is represented by a bias in a generation amount of a plurality of frequency bands of the digital data decomposed by each of the conversion units. 18. The data processing device according to item 17. 22. The different kind of digital data is different from the digital data, and information for managing the digital data such as a copyright holder name, a manufacturing date, a manufacturing place, and a manufacturing number of the digital data, and the digital data. 22. The data processing apparatus according to claim 12, wherein the data processing apparatus is at least one of watermark information of information for protecting data from unauthorized use. 23. The method according to claim 12, wherein the watermark information is inserted based on a secret key kept secret in accordance with each of the classified digital data. Data processing device. 24. The data according to claim 12, wherein the watermark information is inserted based on a public key that is published according to each of the classified digital data. Processing equipment. 25. Input means for inputting digital data, conversion means for converting the form of the digital data,
A data processing device that includes an embedding unit that inserts foreign digital data into the digital data whose form has been converted, and that inserts the foreign digital data in an optimal state according to the characteristics of the digital data; and In a data management system, comprising: a management device that maintains information on a key that defines a method for inserting data, wherein the management device provides information on the key when predetermined authentication information is input. A data management system characterized by the following. 26. The digital data includes image data,
26. The data management system according to claim 25, wherein the data management system is at least one of digital data such as voice data, text data, and program data. 27. The input means is connectable to at least one of digital electronic devices such as a scanner, a digital still camera, a digital video camera, and a computer, and can input digital data from the digital electronic device. The data management system according to claim 25 or 26, wherein 28. The data management system according to claim 25, wherein said conversion means performs one of conversion processes such as a discrete wavelet transform, a discrete cosine transform, and a discrete Fourier transform. 29. The data management system according to claim 28, wherein said conversion means decomposes said digital data into a plurality of frequency components. 30. The data management system according to claim 28, wherein said conversion means decomposes said digital data into a plurality of frequency bands. 31. The data management system according to claim 28, wherein the characteristic of the digital data is represented by a bias in a generation amount of a plurality of frequency components of the digital data decomposed by the conversion unit. 32. The data management system according to claim 28, wherein the characteristic of the digital data is represented by a bias in a generation amount of a plurality of frequency bands of the digital data decomposed by the conversion unit. 33. The heterogeneous digital data, which is different from the digital data, includes information for managing the digital data such as a copyright holder name, a manufacturing date, a manufacturing location, and a serial number of the digital data, and the digital data. The data management system according to any one of claims 25 to 32, wherein the data management system is at least one of watermark information of information for protecting data from unauthorized use. 34. The data management system according to claim 25, wherein the key is a secret key kept secret. 35. The data management system according to claim 34, wherein there are a plurality of the secret keys, and the secret keys are stored in independently separated databases. 36. The data management system according to claim 25, wherein the key is a public key that is made public. 37. The data management system according to claim 36, wherein there are a plurality of said public keys, and said plurality of public keys are stored in independently separated databases. 38. Input means for inputting digital data, discriminating means for classifying the digital data according to characteristics of the digital data, and a plurality of conversions for converting the form of each of the classified digital data. Means, and a plurality of embedding means for inserting foreign digital data into each of the digital data whose form has been converted,
A data processing device that inserts the heterogeneous digital data in an optimal state according to the characteristics of each of the classified digital data, and a management that maintains and manages information related to a key that defines a method of inserting the heterogeneous digital data. A data management system, comprising: a data management system configured to provide information on the key when predetermined authentication information is input. 39. The digital data includes image data,
The data management system according to claim 38, wherein the data management system is at least one of digital data such as voice data, text data, and program data. 40. The input means is connectable to at least one of digital electronic devices such as a scanner, a digital still camera, a digital video camera, and a computer, and can input digital data from the digital electronic device. The data management system according to claim 38 or 39. 41. The data management system according to claim 38, wherein said discriminating means classifies said digital data by reading a classification code in said digital data. 42. The apparatus according to claim 38, wherein said discriminating means classifies said digital data by analyzing a data stream of said digital data.
2. The data management system according to claim 1. 43. The method according to claim 38, wherein the conversion means performs one of conversion processes such as a discrete wavelet transform, a discrete cosine transform, and a discrete Fourier transform.
3. The data management system according to any one of 2. 44. The data management system according to claim 43, wherein said conversion unit decomposes the classified digital data into a plurality of frequency components. 45. The data management system according to claim 43, wherein said conversion unit decomposes the classified digital data into a plurality of frequency bands. 46. A feature of each of the classified digital data is represented by a bias in a generation amount of a plurality of frequency components of the digital data decomposed by each of the conversion units. 44. The data management system according to 43. 47. A feature of each of the classified digital data is represented by a bias in a generation amount of a plurality of frequency bands of the digital data decomposed by each of the conversion units. 44. The data management system according to 43. 48. The heterogeneous digital data is different from the digital data, and information for managing the digital data such as a copyright holder name, a manufacturing date, a manufacturing place, and a serial number of the digital data and the digital data. The data management system according to any one of claims 38 to 47, wherein the data management system is at least one of watermark information among information for protecting data from unauthorized use. 49. The method according to claim 38, wherein the watermark information is inserted based on a secret key kept secret according to each of the classified digital data. Data management system. 50. The data management system according to claim 49, wherein there are a plurality of said secret keys, and said secret keys are stored on independently separated databases. 51. The data according to claim 38, wherein the watermark information is inserted based on a public key that is published according to each of the classified digital data. Management system. 52. The data management system according to claim 51, wherein a plurality of said public keys are stored in an independently separated database.