JP2004304715A - Network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a network system capable of exchanging digital data and effectively coping with the distribution and output of digital data which can easily and illegitimately be copied even on a network on which different digital units such as a scanner, a printer, a digital music recorder, a digital camera, and an MP3 player coexist. <P>SOLUTION: The network system comprising a plurality of apparatuses includes: an input apparatus having an attachment means for attaching the prescribed attachment information to input information with high immunity and a transmission means for transmitting the input information with the attachment information attached thereto onto a network as attached input information; and an output apparatus having a reception means for receiving the attached input information distributed on the network, an extract means for extracting the attached information from the attached input information received by the reception means, and a discrimination means for deciding the processing of the input information depending on the contents of the attached information extracted by the extract means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the field of image processing of digital image data, and more particularly, to an image processing apparatus and method for embedding a digital watermark in digital image data to protect copyright, prevent forgery, record various information, and store the same. It relates to a storage medium that has been used.
[0002]
[Prior art]
A digital image that treats an image as digital data has a feature that, compared to a conventional analog image, it can be easily copied by a computer or the like without deteriorating the image quality, and can be transmitted through a communication line. Due to the above characteristics, digital images have been easily copied illegally and redistributed. One of the methods for preventing this is a method called digital watermark.
[0003]
Digital watermarks are classified into two categories: an invisible digital watermark that embeds watermark information such as copyright information and user information in an invisible form, and a watermark image such as a logo of a company that holds the copyright on the image. A visible digital watermark that is formed in a visible manner is considered.
[0004]
In an invisible digital watermark, the fact that the watermark information is embedded cannot be recognized at a glance of the embedded image. Therefore, although it is difficult to delete the watermark information, illegal copy and illegal distribution are more easily performed than the visible type. However, even if the digital data is illegally copied or distributed, since the watermark information remains in the digital data, it is necessary to identify the unauthorized user by extracting the user ID or the like embedded as the watermark information. Can be. Here, information on the position of the embedded information in the image or related information (such as an initial value for generating a random number when the embedding position is determined as a random number) is used to extract watermark information. It is assumed that the key information is secretly stored.
[0005]
Typical examples of invisible digital watermarks include a method of performing frequency transformation such as fast Fourier transform, discrete cosine transform, and wavelet transform on an input image and embedding in a frequency domain or a technique of directly embedding in a spatial domain called patchwork. Are known. In general, an invisible digital watermark can be used as it is, and information embedded for tracking illegal use is not removed (it is not restored to the original image), which is an irreversible conversion.
[0006]
In the case of a visible digital watermark, the watermark information is written in a visible form on the digital image, so that it is difficult to use it as it is, and there is an effect of discouraging illegal copying and unauthorized distribution. Conventionally, as a method of embedding a visible digital watermark, each pixel value of an image representing a logo or the like of a copyright holder is replaced with the pixel value of the m-th bit of a designated area in the original image, thereby obtaining copyright information. To the original image. Assuming that the least significant bit in the pixel is the 0th bit, m takes a relatively higher bit position so as to be easily recognized by human eyes.
[0007]
Since a visible watermark is difficult to use as it is unlike an invisible watermark, it is necessary to remove the watermark information and restore the original image when using the image. For this purpose, the replaced pixel value of the m-th bit is secretly stored as key information, and the image is restored by replacing the stored pixel value as the key information with the pixel value of the image representing the watermark information again. Thus, in general, a visible watermark is a reversible transform.
[0008]
[Problems to be solved by the invention]
As described above, there are various digital watermarking systems according to their characteristics. Also, there are many input / output devices that use digital watermarks to prevent unauthorized copying and unauthorized output of digital data. However, when those input / output devices independently select a digital watermarking method and embed a digital watermark in data, for example, a corporate logo is overlaid on an output product, or noise is added to digital music data. In this case, regarding the digital watermarking method, the embedding process and the extracting process of the digital watermarking method of each input / output device are in one-to-one correspondence and are not compatible.
[0009]
Therefore, the present invention makes it possible to exchange digital data even on a network in which different digital devices are used in a mixed manner, embed corresponding bits indicating each device in digital data as digital watermark information, and convert the corresponding bits or key information. It is an object of the present invention to provide a network system capable of effectively coping with the distribution and output of digital data in which an illegal copy is prepared by making a configuration in which output cannot be performed if they do not match.
[0010]
[Means for Solving the Problems]
The present invention has been made for the purpose of solving the above-mentioned problems, and has the following configuration as one means for solving the above-mentioned problems.
[0011]
The present invention has been made in view of the above problems, and has as its object to provide a system and a system for efficiently realizing protection of a copyrighted work against various digital watermarking systems.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
(First Embodiment)
FIG. 1 shows a portion related to embedding of a digital watermark in the schematic diagram for explaining the first embodiment of the present invention. In particular, each of the input / output devices is connected to a network and has a configuration in which electronic information can be exchanged, and each input / output device has a configuration in which a digital watermark can be embedded and extracted.
[0013]
Reference numeral 100 in FIG. 1 denotes a multifunction digital copying machine, which includes a scanner unit for inputting digital data, a printer unit for outputting digital data, an image setter unit for storing and storing digital data, a facsimile unit for facsimile transmission and reception, and the like. It is a device composed of
[0014]
Reference numeral 110 denotes a scanner which can input digital data, such as a floodbed scanner.
[0015]
Reference numeral 120 denotes a printer, which is capable of outputting input digital data, such as a laser printer and a BJ printer.
Reference numeral 130 denotes a host computer, which can create and process digital data.
[0016]
An image server 140 stores and stores digital data.
Reference numeral 150 denotes a digital input device, which is a digital camera for inputting digital data, for example, a digital camera for inputting a still image, a digital video camera for inputting a moving image, a digital recorder for inputting audio, and the like.
[0017]
A digital output unit 160 outputs digital data, such as a display for displaying a still image, a digital VCR for displaying a moving image, and a digital player for reproducing sound.
[0018]
Reference numeral 170 denotes a network LAN for connecting each input / output device, and each input / output device has a communication unit connected to the LAN 170.
[0019]
Reference numeral 101 denotes a watermark embedding unit, which is means for embedding a predetermined digital watermark in predetermined digital data. Similarly, 111, 131, 141 and 151 are watermark embedding parts.
[0020]
Reference numeral 102 denotes a watermark extracting unit, which is a unit that performs a process of extracting a predetermined digital watermark from predetermined digital data. Similarly, 122, 132, 142, and 162 are watermark extraction units.
[0021]
Here, the digital watermarking system realized by each of the watermark embedding units 101, 111, 131, 141, and 151 has the following features.
1) The digital watermark realizes a digital watermark which is strong with a relatively small amount of information.
2) The digital watermark can be extracted without a key or with a common key.
3) The digital watermark embeds at least information for specifying each digital watermark method or each input / output device embedded using the digital watermark method.
4) The watermark is resistant to other different watermark embeddings.
[0022]
Various schemes are conceivable as a digital watermark having the above characteristics. The following scheme is shown as an example for explaining the robustness.
[0023]
When the input data that is a copyrighted work is a still image, the image data of the still image is divided into 8 × 8 pixel blocks, and DCT (Discrete Cosine Transform) is performed for each block. Hereinafter, the block subjected to the DCT is referred to as a DCT coefficient block, one coefficient of the DCT coefficient block is referred to as a DCT coefficient, and a set of DCT coefficient blocks of one image is referred to as a DCT coefficient block group.
[0024]
As shown in FIG. 7A, the input image X is DCT-transformed by the image converter 701, and the output DCT coefficient block group is used as the input of the digital watermark embedding unit 702. Then, one DCT coefficient block to be embedded is selected from the DCT coefficient block group, and one DCT coefficient in the DCT coefficient block is quantized to embed one embedded bit. At this time, the size of the quantization step determines the embedding strength, and the size of the quantization step and the position of the selected DCT coefficient correspond to the key information.
[0025]
As an example, the values of the DCT coefficients at the positions of the coordinates u and v are represented by s {u, v}, and the quantization step is represented by h, and the digital watermark bits 0 or 1 are embedded according to the following rules.
a · h <s ｛u, v｝ ≦ (a + 1) · h (1)
Is obtained.
[0026]
When embedded bit = 0 c u, v｝ = b · h + h / 2 (b is an even number of a or a + 1) (2)
When embedded bit = 1 c ｛u, v｝ = b · h + h / 2 (b is an odd number of a or a + 1) (3)
Is performed, and c {u, v} is set as the coefficient after embedding.
[0027]
Finally, the block group is subjected to IDCT (Inverse DCT: Inverse DCT) using the inverse transformer 703 to return to a block of 8 × 8 pixels, which is reconstructed.
[0028]
As shown in FIG. 7B, a DCT coefficient embedded by using a key information by a digital watermark extractor 704 is selected from a group of DCT coefficient blocks subjected to the same DCT using 701 as shown in FIG.
b · h <c ｛u, v｝ ≦ (b + 1) · h (4)
The embedded bit is determined to be 0 if b is an even number, and 1 if b is an odd number.
[0029]
The following method is considered to enhance the tolerance in this embedding method.
[0030]
When one DCT coefficient to be embedded is selected from the DCT coefficient blocks, the resistance can be increased by selecting a DCT coefficient representing a low frequency component. This is because high-frequency components are easily lost by image compression and various filtering processes, while low-frequency components are not easily lost.
[0031]
Further, in the above embedding method, the DCT coefficient block to be selected and the DCT coefficient to be embedded are described as one, but the resistance can be increased by increasing the number. This means that if only one DCT coefficient is embedded in one bit, the value is likely to be lost by image compression or various filtering processes. However, if the same bit is embedded in a plurality of DCT coefficients, This is because the possibility that most of them are lost is reduced.
[0032]
In addition, the robustness can be enhanced by performing error correction coding on the embedded bits themselves. This is because even if some of the embedded bits are lost, they can be restored by the error correction code. Here, it is clear that the higher the correction capability of the error correction code used, the stronger the tolerance. However, although these techniques increase the robustness, the quality of the image deteriorates because the low frequency components of the image are changed or many bits are embedded.
[0033]
Also, since the same bit is embedded using many DCT coefficients, the number of bits that can be embedded is often reduced. If the reverse operation is performed, a digital watermarking method can be realized in which the image quality is good but the amount of information that can be embedded is large, although the resistance is weak.
[0034]
The method of enhancing the above-described tolerance is not limited to the method using DCT, and it can be said that the same tendency applies to a method using wavelet transform or Fourier transform, and a method for directly operating the luminance value of a pixel.
[0035]
Next, a watermark embedding procedure will be described with reference to FIG. Here, the information to be embedded by the digital watermark is set to 000, 001, 010, 011, 100, 101, 110, and 111 as corresponding bits as shown in FIG. 2 for simplicity. This is a 3-bit device that specifies a device capable of transmitting and receiving digital data to and from the multifunction copier 100, the scanner 110, the printer 120, the host computer 130, the image server 140, the digital input device 150, and the digital output device 160. The number of bits is not limited to this, and the number of bits is not limited to this. Instead of individually assigning corresponding bits, the type of device, for example, add 000 for a printer device and 100 for a scanner device. It is clear that other information can be set at the same time.
[0036]
Also, each of the multifunction copier 100, the scanner 110, the printer 120, the host computer 130, the image server 140, the digital input device 150, and the digital output device 160 having corresponding bits has the watermark embedding units 101 and 111 respectively. , 131, 141, 151 and the watermark extraction units 102, 122, 132, 142, 162 have common key information.
[0037]
Reference numerals 200, 210, and 220 denote digital input / output devices each having no corresponding bit. The digital input / output device 200 has a watermark embedding portion, but the 210 does not have a watermark embedding portion. Reference numeral 220 has a watermark embedding part but different key information.
[0038]
Each device uses the watermark embedding units 101, 111, 131, 141, and 151 with respect to the digital data distributed on the LAN 170, using the watermark embedding units 101, 111, 131, 141, and 151 to apply a highly durable digital watermark having the above-described features (1) and (4). Embed the bit corresponding to. For example, in the case of the multifunction copying machine 100, 000 is embedded, and in the case of the digital input device 150, 101 is embedded.
[0039]
The digital data distributed on the LAN 170 extracts embedded information by a digital watermark using the watermark extracting units 102, 122, 132, 142, and 162. In this way, a device in which a predetermined watermark is embedded is specified, and whether to output the digital data is determined.
[0040]
That is, based on the information of the digital watermark, the digital data delivered to the output device is not the digital data input by an unauthorized means, but the input device such as a predetermined multi-function copier 100, scanner 110, digital input device 150, or the like. Is determined from the corresponding bit of the input device. It also determines that the digital data distributed via the LAN 170 is digital data stored and stored in a predetermined host computer 130, image server 140, or the like. As a result of the determination, if the device is authenticated as a predetermined device, the distributed digital data is output. If the device is not authenticated, the distributed digital data is not output.
[0041]
Furthermore, when extracting watermarks from the distributed digital data, the distributed digital data is not output even if the key information does not match or the watermark information cannot be obtained.
[0042]
For example, when digital data distributed from the digital music recorder as the digital input device 150 is output by the digital music player as the digital output device 160, the watermark embedding section 151 on the digital input device 150 outputs the corresponding bit. 101 is embedded and distributed to the digital output device 160 via the LAN 170. In the digital output unit 160, the watermark extraction unit 162 extracts a digital watermark, obtains the corresponding bit 101, compares the corresponding bit with a corresponding bit table described in a storage device (not shown), and gives output permission. If it is determined that the digital data is good, output is performed.
[0043]
If this is digital data delivered from the digital input device 200 that does not have a corresponding code even if it has a watermark embedding portion, the digital watermark can be extracted by the watermark extracting portion 162 of the digital output device 160. Bits cannot be extracted, and the digital output unit 160 cannot output. Further, in the case of distribution from the digital input device 210 having no watermark embedding section, the digital output device 160 cannot perform output because the watermark information is not included. Even when the digital input device 220 embeds the watermark information by the digital watermark embedding method with different key information even if it has a watermark embedding section, the digital output device 160 outputs because the key information is different. I can't do that.
[0044]
According to the present invention, even on a network in which different digital devices are used in a mixed manner, a corresponding bit indicating each device is embedded in digital data as digital watermark information, and if the corresponding bits or key information do not match, output cannot be performed. This makes it possible to deal effectively with the distribution and output of digital data prepared by an unauthorized copy.
[0045]
(Second embodiment)
FIG. 3 is a schematic diagram for explaining the second embodiment of the present invention, in which the embedding of a digital watermark is performed by a third party organization by a watermark information management organization shown in 300. FIG.
[0046]
Reference numerals 100, 110, 120, 130, 140, 150, 160, 170 and the watermark extraction unit provided therein are those of FIG. 1 shown in the first embodiment, and reference numeral 300 denotes a watermark information management institution; It is an institution that performs embedding.
[0047]
For simplicity, the same reference numerals are used for those shown in the previous embodiment, and the description is omitted. In addition, the watermark information management institution 300 can be considered as a unified copyright management institution such as JASRAC for music works, an institution that handles publishing-related copyrights, and a sales company of each device. It is conceivable that 120, 130, 140, 150, 160, and the like exist in a form like a store that sells a copyrighted work managed by the watermark information management organization 300 to a user. The present invention does not specify the form of the present invention, but manages a device corresponding to the watermark information, and when the corresponding bit or the key information of the watermark matches, it is possible to output the distribution digital data on the network. It is the invention intended.
[0048]
In this case, digital data input by the multi-function copying machine 100 or input by the scanner 110 is registered in the watermark information management organization 300, and the watermark embedding unit 301, which is a digital watermark embedding unit, embeds the corresponding bit. Is given. In FIG. 3, 000 is the information embedded in the multifunction copier 100 and 001 is the information embedded in the scanner 110 as the corresponding bits.
[0049]
After embedding the digital watermark information in the digital data, the watermark information management institution 300 may store the digital watermark information in a storage device (not shown), may return the digital watermark information to the multifunction copier 100 and the scanner 110, or may request the printer 120 Thus, digital data may be transmitted to the printer 120.
[0050]
In any case, the digital data in which the corresponding bits are embedded as the digital watermark information are extracted by the watermark extracting unit 122, and when the key information matches and the corresponding bits are authenticated to be permitted to be output, the printer is authenticated. 120.
[0051]
For example, the digital music data recorded by the digital music recorder serving as the digital input device 150 is added with watermark information by the watermark information management institution 300 to perform copyright protection. After that, when downloading the digital music data to the digital music player, which is the digital output device 160 of the user who wants to obtain the digital music data, the user receives key information instead of being charged and receives the key information from the digital music data based on the key information. Extract watermark information. Then, by comparing the corresponding bit information in the watermark information with the corresponding bits registered in the digital music player in advance, if authentication is obtained, reproduction becomes possible. In this case, the manufacturer of the digital music player embeds the corresponding bit indicating the digital music recorder of the manufacturer in the digital music player in advance, and authenticates the corresponding bit extracted from the watermark information without making the user aware. Alternatively, the corresponding bit may be sent in advance from a digital music data distribution site that the user prefers on the network, and stored in a digital music player to store the digital music data in the distributed digital music data. The watermark information may be extracted and the corresponding bits may be compared.
[0052]
(Third embodiment)
In the first and second embodiments, for example, in the image server 140 shown in FIG. 1, the watermark embedding unit 141 embeds digital watermark information into input information, but before embedding the digital watermark information. In the watermark extraction unit 142, the digital data in which the digital watermark information is embedded is examined to determine whether the watermark information has already been embedded. If the digital data is embedded, the digital watermark information may not be overwritten. The digital watermark information may be embedded by the watermark embedding unit 141 so as to overwrite the digital watermark information or not to affect the previous watermark information.
[0053]
【The invention's effect】
As described above, according to the present invention, even on a network in which different digital devices are used in a mixed manner, exchange of digital data becomes possible, and a corresponding bit indicating each device is embedded in digital data as digital watermark information. If the corresponding bits or the key information do not match, by making the configuration impossible to output, it is possible to deal effectively with the distribution and output of digital data in which an illegal copy is prepared.
[Brief description of the drawings]
FIG. 1 is an exemplary view for explaining the outline of embedding and extracting a digital watermark in a first embodiment;
FIG. 2 is an exemplary view for explaining an outline of corresponding bits of a digital watermark according to the first embodiment;
FIG. 3 is an exemplary view for explaining an outline of a watermark information management organization according to the second embodiment;
FIG. 4 is a conceptual diagram illustrating a process of embedding and extracting a digital watermark.
[Explanation of symbols]
100 MFP
101 watermark embedding unit 102 watermark extracting unit 110 scanner 111 watermark embedding unit 120 printer 122 watermark extracting unit 130 host computer 131 watermark embedding unit 132 watermark extracting unit 140 image server 141 watermark embedding unit 142 watermark extracting unit 150 digital input device 151 watermark embedding unit 160 digital output unit 162 watermark extracting unit 170 LAN

Claims (26)

In a network system consisting of multiple devices,
An adding unit for adding predetermined additional information to the input information with a strong tolerance;
Transmitting means for transmitting the input information to which the additional information is added, as additional input information over a network;
An input device having
Receiving means for receiving the additional input information distributed on the network,
Extracting means for extracting the additional information from the additional input information received by the receiving means,
Determining means for determining the handling of the input information according to the content of the additional information extracted by the extracting means;
An output device having
A network system comprising: 2. The network system according to claim 1, wherein the additional information is information for specifying an address on the network of a device that transmits the additional input information using the additional unit and the communication unit. Network system. 2. The network system according to claim 1, wherein the additional information is information that can specify a type of a device that transmits the additional input information using the additional unit and the communication unit. 2. The network system according to claim 1, wherein the adding unit embeds the additional information as watermark information. 2. The network system according to claim 1, wherein the input device and the output device may be on the network as a device having both of them, and may be on the network as a device having only one function. A network system characterized in that it does not matter. 2. The network system according to claim 1, wherein said extracting means extracts watermark information from the additional input information. 2. The network system according to claim 1, wherein said adding means and said extracting means use common secret information when embedding and extracting a watermark. 2. The network system according to claim 1, wherein the secret information is a position of the additional information or a change amount with respect to the additional information. 2. The network system according to claim 1, wherein the extracting unit extracts the additional information from the input additional information in the extracting unit, and when the additional information cannot be extracted using the secret information. A network system that does not output the input information. 2. The network system according to claim 1, wherein the extracting unit extracts the additional information from the input additional information in the extracting unit, and when the additional information cannot be extracted by using the secret information. 3. Does not output the input information. 2. The network system according to claim 1, wherein the determination unit extracts the additional information from the input additional information in the extraction unit, and determines whether output is permitted or not according to a bit value that is the content of the information. A network system, characterized in that: 2. The network system according to claim 1, wherein the determination unit extracts the additional information from the input additional information in the extraction unit, and an address on the network described in the additional information is set in advance. A network system that does not perform output if the address does not match a plurality of addresses. 2. The network system according to claim 1, wherein the determination unit extracts the additional information from the input additional information in the extraction unit, and a plurality of types of devices described in the additional information are set in advance. A network system that does not perform output when the type of device does not match the device type. 2. The network system according to claim 1, wherein, when adding the additional information to the input information, the additional unit checks the previous additional information using the corresponding extraction unit. 3. A network system characterized by the following. In a network system consisting of multiple devices,
Input means for inputting input information;
Transmission means for transmitting the input information input by the input means on a network,
An input device having
An adding unit that receives the input information distributed on the network, and strongly adds predetermined additional information to the received input information;
Transmitting means for transmitting the input information to which the additional information is added, as additional input information over a network;
An information management organization with
Receiving means for receiving the additional input information distributed on the network,
Extracting means for extracting the additional information from the additional input information received by the receiving means,
Determining means for determining the handling of the input information according to the content of the additional information extracted by the extracting means;
An output device having
A network system comprising: 16. The network system according to claim 15, wherein the information management institution embeds information specifying an address on the network of the input device to which the input information has been input, as the additional information by the adding unit. Network system. 16. The network system according to claim 15, wherein the information management organization embeds information for specifying the type of the input device into which the input information has been input by the adding unit as the additional information. Network system. 16. The network system according to claim 1, wherein the input device is a still image input device such as a scanner for inputting a still image such as paper or a photograph. 16. The network system according to claim 1, wherein the input device is a still image input device such as a digital camera for inputting a still image of a person, a landscape, or the like. 16. The network system according to claim 1, wherein the input device is a moving image input device such as a digital video camera for inputting a moving image of a sport, a running train, or the like. 16. The network system according to claim 1, wherein the input device is a voice input device such as a digital music recorder that inputs voice information such as music and voice. 16. The network system according to claim 1, wherein the input device is a character / line input device such as a tablet for inputting character information such as handwritten characters and lines. 16. The network system according to claim 1, wherein the output device is a still image output device such as a printer that outputs a still image. 16. The network system according to claim 1, wherein the output device is a moving image output device such as a digital video player that outputs a moving image. 16. The network system according to claim 1, wherein the output device is an audio output device such as a digital music player that outputs audio information. 26. The network system according to claim 18, wherein said input device and said output device are input / output devices having overlapping functions.

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