JP2002359805A - Device and method for processing electronic watermark embedding, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a configuration capable of electronic watermark embedding that has resistance to various kinds of data conversion processing reinforced. SOLUTION: Data processing, such as encoding, decoding and word length processing is applied to an input signal to predict deterioration quantity, in the case of performing electronic watermark embedding processing of the input signal, and an electronic watermark pattern corrected, on the basis of prediction results, is generated and embedded into the input signal. Resistance to data processing, such as encoding and word length processing, is reinforced to be able to secure reliability of electronic watermark detection by reducing an embedding level of an area to be deteriorated with data conversion processing for making reallocation to parts that are not deteriorated, controlling the overall embedding intensity to fixed quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for embedding or reading additional information such as copyright information and editing information in data of an image or the like. The present invention relates to a digital watermark embedding processing apparatus, a digital watermark embedding processing method, and a program that execute processing for embedding (watermark: also referred to as Digital Watermarking or DataHiding).

[0002]

2. Description of the Related Art With the advancement of digital technology, digital recording / reproducing apparatuses that do not cause image quality deterioration and sound quality deterioration due to repeated execution of recording and reproduction processing have become widespread.
Various digital and digital contents such as music, DVD,
It can be distributed and distributed through media such as CDs or networks.

In digital recording / reproducing, unlike analog recording / reproducing, data deterioration does not occur even if recording / reproducing processing is repeatedly executed, so that the same quality as original data is maintained. The spread of such digital recording / reproducing technology has resulted in the proliferation of illegal copying, and is a serious problem from the viewpoint of copyright protection.

In order to cope with copyright infringement due to unauthorized duplication (copy) of digital content, copy control information for copy control is added to the digital content,
There has been proposed a configuration in which duplication control information is read at the time of recording and reproduction of content, and a process according to the read control information is executed to prevent unauthorized duplication.

There are various modes of content copy control. For example, as a typical method, CGMS (Copy
Generation Management Sys
tem; copy generation management
System) system. In the CGMS method, if an analog video signal (referred to as CGMS-A), a specific horizontal section within a vertical blanking period of the luminance signal,
For example, in the case of an NTSC signal, two bits of the 20-bit additional information to be superimposed on the effective video portion in the twentieth horizontal section are superimposed as duplication control information, and a digital video signal (referred to as CGMS-D). ), The transmission method includes 2-bit information for duplication control as additional information to be inserted and added to digital video data.

The meaning of 2-bit information (hereinafter referred to as CGMS information) in the case of the CGMS system is [00]
... Duplicatable [10]... Duplicate once (only one generation can be duplicated). [11]... Duplicate prohibited (absolute duplicate prohibition).

The above-mentioned CGMS system is an example of a typical copy control system, and there are various other systems for protecting the copyright of contents. For example, in digital broadcasting performed by a broadcasting station, program sequence information (S) included in a transport stream (TS) packet constituting digital data.
There is a method in which a digital copy control descriptor (Digital Copy Control Descriptor) is stored in I: Service Information, and the copy generation control according to the descriptor is performed when data received by the receiving device is recorded in the recording device.

However, the above-mentioned control information is added as bit data to, for example, a header of the content, and it is difficult to completely eliminate the possibility of falsification of the added data. An advantageous configuration in terms of eliminating the possibility of data tampering is a digital watermark. Digital watermarks (watermarks) are difficult to see or perceive during normal content (image data or audio data) playback, and detection and embedding of digital watermarks can only be performed by executing a specific algorithm or processing by a specific device. It becomes possible. By detecting a digital watermark (watermark (WM)) at the time of content processing in a receiver, a recording / reproducing device, and the like, and performing control in accordance with the digital watermark, control with higher reliability can be performed.

[0009] The copyright protection method using a digital watermark (watermark (WM)) for a recording medium such as an optical disk or a content transmitted from a broadcasting station or the like via a medium such as a satellite wave, a terrestrial wave, or a cable is disclosed. In addition, a modulation signal or the like of data relating to copyright is superimposed and recorded on a video signal, an audio signal, or the like at a very small signal level that does not affect reproduction of a video signal or an audio signal. In the age of digital networks where various digital contents such as images, sounds, and data can be copied and distributed without deterioration, digital watermarking technology protects copyrights by embedding information in the contents themselves. It is a powerful technology that can do.

Digital watermark (watermark (WM))
The information embedded in the content is not limited to the above-described copy control information, and various information such as the copyright information of the content, the content processing information, the content configuration information, the content processing information, the content editing information, and the content reproduction processing method. Can be embedded. For example, the editing information is embedded at the time of editing the content, and in each editing step, the processing step is confirmed by referring to the digital watermark. For example, such editing information is embedded in the content as a new digital watermark in the content at each editing step, and is finally removed from the content.

Various techniques have been proposed for embedding and detecting a digital watermark in data. One typical digital watermark embedding detection mode includes a method based on data as an original signal, for example, a statistical property of an image. A method for embedding a digital watermark based on PN sequence random number data as a basic pattern based on the statistical properties of an image signal such as a digital video signal will be described. For simplicity, the frame data of the luminance signal has a horizontal size of 8 pixels and a vertical size of 6 pixels.

First, PN sequence random number data PN is set as in the following equation.

[0013]

(Equation 1)

The random number data PN is generated so that the total sum is statistically zero. Next, the embedded information DC is spectrum-spread by random number data PN having the property as shown in the above equation. That is, the polarity of the embedded information DC is “1”.
In the case of, by using the pattern of the random number data PN as it is, the digital watermark pattern WM is represented by the following equation.

[0015]

(Equation 2)

When the polarity of the embedding information DC is "0", the digital watermark pattern WM is expressed by the following equation by using a pattern obtained by inverting the pattern of the random number data PN.

[0017]

(Equation 3)

When the embedding information DC is composed of a plurality of information bits, for example, the frame data of the luminance signal may be divided into appropriate small areas, and each information bit may correspond to each small area. Also, for example, using a plurality of different digital watermark patterns that are orthogonal to each other,
What is necessary is just to make each information bit correspond to each digital watermark pattern. Further, these techniques may be used in combination.

On the other hand, in an image signal such as a digital video signal, it is assumed that frame data DV1 indicating a luminance signal pixel value of certain frame data is represented by the following equation.
In addition, in the image signal of the digital video signal, there is a property that adjacent luminance signals have similar pixel values,
The values of adjacent pixels are set to approximate values.

[0020]

(Equation 4)

The embedding of the digital watermark is realized by adding a digital watermark pattern WM to the frame data DV1 of the luminance signal. When the polarity of the digital watermark embedding information DC is “1”, the digital watermark pattern WM shown in the above [Equation 2] is added to the luminance signal shown in the above [Equation 4]. Is embedded, the frame data DV2 of the luminance signal is data represented by the following equation.

[0022]

(Equation 5)

From the frame data DV2 of the luminance signal in which the digital watermark is embedded in this manner, the embedded information DC
Is detected, random number data PN of the same PN sequence as at the time of embedding is used. First, the inner product value P1 of the frame data DV1 of the original luminance signal and the random number data PN has a value represented by the following equation.

[0024]

P1 = DV1 · PN = 1

From the statistical properties of the image signal, the inner product P
1 is a value near 0. On the other hand, the frame data DV2 of the luminance signal in which the digital watermark is embedded and the random number data P
The inner product value P2 with N indicates that the polarity of the embedded information DC is “1”.
Has a value represented by the following equation.

[0026]

P2 = DV2 · PN = (DV1 + WM) · PN = (DV1 + PN) · PN = P1 + PN ² = 1 + 48

On the other hand, when the polarity of the embedded information DC is "0", it has a value represented by the following equation.

[0028]

[Equation 8] P2 = DV2 · PN = (DV1 + WM) · PN = (DV1-PN) · PN = P1-PN 2 = 1-48

[0029] That is the absolute value of the inner product value P2 is a inner product value PN ² near the value of the random number data PN itself. The inner product value P of the frame data DV1 of the original luminance signal and the random number data PN
1 and the inner product value P2 of the frame signal DV2 of the luminance signal in which the digital watermark is embedded and the random number data PN are calculated for various images, the distribution of the inner product values P1 and P2 is represented by a probability density function as shown in FIG. Can be expressed. Therefore, by setting an appropriate non-negative threshold value TH, it is possible to determine the presence / absence and polarity of a digital watermark as described below.

[0030]

P2 ≦ −TH: With digital watermark (polarity 0) | P2 | <TH: Without digital watermark P2 ≧ TH: With digital watermark (polarity 1)

As shown in the above equation, from the frame data DV2 of the luminance signal in which the digital watermark is embedded, the embedded information DC
Can be detected.

In realizing a digital watermark, two important points are reliability of digital watermark detection and influence of the digital watermark on image quality. In order to accurately determine the presence or absence of a digital watermark, a threshold TH that accurately separates the probability density function in the case of “with digital watermark” and the probability density function in the case of “without digital watermark” in FIG. 1 is used.
Must be set. In practice, however, the tails of the probability density functions overlap, and it is difficult to select a threshold value TH that can accurately determine the presence or absence of a digital watermark. The probability of being determined as “with digital watermark” even though the digital watermark is not embedded is particularly called False Positive, and an extremely small False Positive value is required to guarantee sound content distribution. Therefore, in order to improve the reliability of digital watermark detection,
A process of increasing the embedding strength of the digital watermark using the non-negative scalar amount C is executed. The frame data DV2 of the luminance signal when the digital watermark is embedded by increasing the digital watermark embedding strength using the scalar amount C has a value represented by the following equation.

[0033]

## EQU10 ## DV2 = DV1 + CWM

The inner product value P2 of the frame data DV2 of the luminance signal in which the digital watermark is embedded and the random number data PN may be made sufficiently large. Specifically, the frame data DV2
Has a value represented by the following equation.

[0035]

P2 = DV2 · PN = (DV1 + CWM) · PN = (DV1 ± PN) · PN = P1 ± CPN ²

However, when the embedding strength of the digital watermark is increased in this way, the effect of the digital watermark on the image quality cannot be ignored. There is a trade-off between the reliability of digital watermark detection and the effect of digital watermark on image quality.

In order to minimize the influence of the digital watermark on the image quality while ensuring the reliability of the digital watermark detection, a method of embedding the digital watermark by effectively utilizing the human visual characteristics has been proposed. These methods take into account the human visual characteristics, redistribute the digital watermark pattern in the image, make the digital watermark pattern follow the movement of the image, and so on, without changing the overall embedding strength. The effect of watermark on image quality is effectively suppressed. The human eye is sensitive to changes in a low frequency region such as a flat portion, but is insensitive to changes in a high frequency region such as an edge portion. By using this to redistribute the digital watermark pattern from a flat portion that is conspicuous to an edge portion that is not conspicuous, it is possible to suppress the influence on the image quality of the digital watermark while securing the reliability of the digital watermark detection. When the image is stationary, the digital watermark pattern is also stopped, and when the image is moving, the digital watermark pattern is also moved, thereby embedding a digital watermark so that it is difficult for human eyes to perceive. be able to.

Further, even when various attacks such as image format conversion, digital-analog conversion, MPEG compression, filtering, clipping, resizing, and rotation are applied to the image in which the digital watermark is embedded, the embedded electronic watermark can be obtained. The watermark information must be detected correctly. Anyone who attempts to unfairly infringe on copyrights could maliciously attack these images with embedded watermarks. Therefore, various techniques have been proposed to enhance the resistance to these attacks and ensure the reliability of digital watermark detection. However, a digital watermarking technique that is robust against all kinds of attacks has not yet been developed, and urgent countermeasures are desired.

FIG. 2 is a diagram for explaining a mode in which copy control information is embedded in data using a digital watermark and copy control is performed by detecting a digital watermark.

Digital video signal D which is a video source
V is transmitted from a broadcasting station or the like via a medium such as a satellite wave, a terrestrial wave, or a cable.
When 0, digital watermark information DC is added and transmitted. The digital watermark information DC to be embedded here is composed of copyright information of a video source and the like, and has information of “Copy Once” (copy once).

As described above, “Copy Once” (1
Among the digital video signals transmitted with the information of “copy once” embedded in the digital watermark, the digital video signal to be received and reproduced by the set-top box or the like is used to convert the reproduced digital video signal into a digital watermark incorporated in the recording device 2. The digital watermark information DC embedded by the detection device 3 is detected.

When the digital watermark detecting device 3 built in the recording device 2 detects the digital watermark information “Copy Once”, the digital watermark rewriting device 4 built in the recording device 2 rewrites the digital watermark information DC and rewrites the optical disk 5. Etc. The digital watermark information DC to be rewritten here is composed of the copyright information of the video source, etc.
re Copy "(copy prohibited).

When the optical disk 5 copied and recorded by the recording device 2 in this way is provided, for example, as a medium distributed in the market, the provided copy recorded optical disk 5
When the digital watermark is copied again in the recording device 6, the digital watermark information DC embedded therein is detected from the digital video signal reproduced by the digital watermark detection device 3 built in the recording device 6.

The digital watermark information DC in this case is information of “No More Copy” which does not permit duplication, and the recording device 6 performs processing in accordance with “No More Copy”, that is, reproduces the reproduced digital video signal on the optical disc. Stop recording at 7. Thus, the copy generation is managed.

The digital watermark embedding processing device 100
When manufacturing an optical disc 8 storing a digital video signal DV as a video source, "Never Co."
It is assumed that a process of adding digital watermark information DC having information of “py” (copy prohibition) to the optical disk 8 or the like and executing the process is performed.

When the optical disk 8 thus recorded is distributed in the market, the provided optical disk 8
Is reproduced by the recording device 6 and is to be copied to another recording medium, the digital watermark detection device 3 incorporated in the recording device 6 detects the embedded digital watermark information DC from the reproduced digital video signal.

In this case, the digital watermark information DC is information of “Never Copy” (copy prohibited) for which copying is not permitted, and the recording device 6 transmits the “Never Copy”.
The processing according to y ″, that is, the recording of the reproduced digital video signal on the optical disk 7 is stopped.

As described above, in an environment in which the data subjected to the digital watermark embedding processing is thereafter subjected to data processing such as compression, encoding, and conversion processing, and the recording apparatus performs the duplication data generation processing in the recording apparatus. Thus, the copy control by the digital watermark embedded in the data is almost surely executed. Next, the effect when data conversion processing is performed on data on which digital watermark embedding processing has been performed will be described.

For an image signal such as a digital video signal, MPEG2 (M
oving Picture Experts Grou
p-2), and MPEG2 has been adopted as a moving picture coding standard for digital broadcasting and DVDs. The moving image content compressed by MPEG2 encoding is transmitted from a broadcasting station or the like via a medium such as a satellite wave, a terrestrial wave, or a cable, or is recorded and distributed on a recording medium such as an optical disk. The original digital video signal can be reproduced by expanding by decoding. Therefore, when a digital watermark is embedded in a digital video signal in advance, when the digital video signal in which the digital watermark is embedded is compressed by MPEG2 and recorded, the digital watermark information embedded as described above is used as the MPE.
There is a possibility that the embedded information such as copyright information cannot be correctly detected due to deterioration due to the G2 compression processing. It is necessary to enhance the resistance to image encoding such as MPEG2 and to ensure the reliability of digital watermark detection.

FIG. 3 is a diagram for explaining a problem of control based on copy control information when image encoding is performed on data in which a digital watermark is embedded. When the digital watermark embedding processing apparatus 1001 records the digital video signal DV as the video source, the digital watermark information DC
Is recorded on the optical disk 12 or the like. Here, it is assumed that the digital watermark information DC to be embedded is composed of copyright information of a video source and the like, and is composed of information “Never Copy”.

The optical disk 12 recorded as described above
When the supplied optical disk 12 is reproduced on the recording device 13 and is to be copied to another recording medium, the digital video signal DV ( B
The digital watermark information DC embedded from B) is detected.

The digital watermark information DC in this case is information of “Never Copy” (copy prohibited) for which copying is not permitted, and the recording device 13 transmits the “Never Copy”.
py ", that is, the recording of the reproduced digital video signal DV (BB) on the optical disk 14 is stopped.

However, the digital watermark embedding processing device 1
Consider a case where the optical disc 12 on which data is recorded by embedding a digital watermark by 1 is subjected to compression processing by an image encoding device 15 such as MPEG2, and the optical disc 16 recorded as compressed data is distributed to the market. In a medium such as the optical disk 16 on which compressed data is recorded, digital watermark information embedded before the compression processing by the image encoding device 15 may be deteriorated by image encoding.

With respect to a medium such as the optical disk 16 storing such compressed data, the recording apparatus 17 which detects digital watermark information and executes copy control reproduces the data, and attempts to copy the data to another recording medium. In this case, the digital watermark detection device 171 incorporated in the recording device 17 attempts to detect the digital watermark information DC embedded from the digital video signal (bit stream signal) DV (BS) reproduced from the optical disc 16, but the data compression processing is performed. The digital watermark exceeding the threshold is not detected, and the digital watermark information DC, which was originally “Never Copy” information, cannot be correctly detected, and a conclusion “No Watermark” can be made. There is. In this case, it is possible to record the reproduced digital video signal (bit stream signal) DV (BS) on the optical disk 18, and it is not possible to prevent illegal copying.

In a recording device 19 for decoding data stored on the optical disc 16 and recording the data on another medium, an image decoding device 191 incorporated in the recording device 19 is
Played digital video signal (bit stream signal)
DV (BS) is expanded by MPEG2 decoding, and then
The digital watermark information DC embedded by the digital watermark detection device 192 for the baseband signal is to be detected from the digital video signal (baseband signal) DV (BB) reproduced as the decoded data. There is a possibility that a digital watermark exceeding the threshold cannot be detected due to deterioration, and the digital watermark information DC which was originally “Never Copy” cannot be correctly detected, and a conclusion “No Watermark” may be made. . In this case, the reproduced digital video signal (bit stream signal) DV (BS) can be recorded on the optical disc 20, and illegal copying cannot be prevented.

Next, the effect when the word length conversion process is executed as the data conversion process will be described. In an image signal such as a digital video signal, the word length of the luminance signal value is predetermined to be 8 bits or 10 bits in format. Therefore, for example, a digital watermark embedding process is performed on a luminance signal having a word length of 10 bits, and thereafter, a 10b
When it is converted from 8-bit data to 8-bit data (word length conversion), the embedded digital watermark information may be degraded by the word length conversion, and embedded information such as copyright information may not be correctly detected. Therefore, it is necessary to enhance the resistance to such word length conversion and ensure the reliability of digital watermark detection.

The word length conversion processing will be described with reference to FIG. The data shown in FIG. 4A is 10-bit data, and is transmitted from MSB (Most Significant Bit) b ₉ to LSB (L
eastSignificant Bit) to b _0, with a 10bit configuration. When converting this to a 8bit data by word length converter 25, it executes the processing of truncating the 2bitb _0, b ₁ on the LSB side. The result of this process, the data is converted to 8bit of b ₉ ~b _2. When such a change or processing is executed, the digital watermark data is converted to the LSB side 2 bitb ₀ ,
If embedded as only existing in b _1, after word length conversion can not be of the digital watermark detection.

FIG. 5 is a diagram for explaining a problem of control based on copy control information when word length conversion is performed on data in which a digital watermark is embedded. When recording a digital video signal DV as a video source, the digital watermark embedding processing device 21 adds digital watermark information DC and records the digital video signal DV on an optical disk 22 or the like. Here, it is assumed that the digital watermark information DC to be embedded is composed of copyright information of a video source and the like, and is composed of information “NeverCopy”.

The optical disk 22 recorded as described above
If the supplied optical disk 22 is reproduced on the recording device 23 and is to be copied to another recording medium, the digital watermark signal DV (DV) reproduced by the digital watermark detection device 231 built in the recording device 23 B
The digital watermark information DC embedded from B) is detected.

In this case, the digital watermark information DC is information of “Never Copy” (copy prohibited) for which copying is not permitted, and the recording device 23 transmits “Never Copy”.
py ", that is, the recording of the reproduced digital video signal DV (BB) on the optical disk 24 is stopped.

However, the digital watermark embedding processing device 2
When the word length conversion device 25 executes a word length conversion process from 10 bits to 8 bits on the optical disk 22 on which data is recorded by embedding a digital watermark by using step 1, digital watermark information is detected and converted for the converted data. When the recording device 26 performing the control attempts to copy data to another recording medium, the digital watermark detection device 261 incorporated in the recording device 26 will detect the digital watermark information DC based on the word length conversion data. However, since the digital watermark is deteriorated due to the word length conversion processing, the digital watermark exceeding the threshold is not detected, and originally “Never Cop”
There is a possibility that the digital watermark information DC which was the information “y” may not be correctly detected and the conclusion “No Watermark” may be made. In this case, the reproduced digital video signal (bit stream signal) DV (B
S) can be recorded on the optical disk 28, and illegal copying cannot be prevented.

As described above, if various processes are performed on the data after the digital watermark embedding process, the effect on the embedded digital watermark may occur, and correct digital watermark detection may not be performed. .

[0063]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above-described problems. A digital watermark embedding processing device that enables reliable detection of a digital watermark from data of the same, enhances resistance to data processing such as signal encoding and word length conversion, and secures reliability of digital watermark detection; and An object of the present invention is to provide a watermark embedding processing method and a program.

[0064]

SUMMARY OF THE INVENTION A first aspect of the present invention is as follows.
An electronic watermark embedding processing device that executes an electronic watermark embedding process, based on an electronic watermark pattern generating unit that generates an electronic watermark pattern based on embedding information, and a data conversion process on an input signal to be subjected to an electronic watermark pattern embedding process. A signal control unit for predicting a deterioration state of the input signal and performing a correction process on the digital watermark pattern generated by the digital watermark pattern generation unit based on the predicted value; and a digital watermark pattern corrected by the signal control unit. And an adder for executing a process of embedding the above in the input signal.

Further, in one embodiment of the digital watermark embedding processing device of the present invention, the signal control means includes a compression / decompression processing means for executing a compression / decompression processing on the input signal as the data conversion processing; Processing means for calculating a difference between the processing data after the compression and decompression processing of the input signal by the processing means and the input signal; and a digital watermark pattern generation means based on the difference data output from the difference calculation means. Signal correction means for performing a correction process of the generated digital watermark pattern.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the signal control means includes an encoding / decoding processing means for executing an encoding / decoding processing on the input signal as the data conversion processing. Processing data after the encoding and decoding processing on the input signal by the encoding and decoding processing means, a difference calculating means for calculating a difference between the input signal, and difference data output from the difference calculating means. And a signal correcting unit for executing a correction process of the digital watermark pattern generated by the digital watermark pattern generating unit.

Further, in one embodiment of the digital watermark embedding processing device of the present invention, the signal control means performs the data conversion processing on the input signal according to an MPEG.
Coding / decoding processing means for executing coding / decoding processing based on the second, calculating the difference between the input data and the processing data after the coding / decoding processing on the input signal by the coding / decoding processing means And a signal correction unit that executes a correction process of the digital watermark pattern generated by the digital watermark pattern generation unit based on the difference data output by the difference calculation unit. And

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the signal control means performs a word length conversion processing on the input signal as the data conversion processing; Processing means for performing a word length conversion process on the input signal by the word length conversion processing means; a difference calculation means for calculating a difference between the input signal; and the digital watermark based on difference data output from the difference calculation means. Signal correction means for executing a correction process of the digital watermark pattern generated by the pattern generation means.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the signal control means determines the deterioration state of the input signal based on the data conversion processing for the input signal to be subjected to the digital watermark pattern embedding processing. The present invention is characterized in that a prediction is performed for each predetermined unit data of a signal, and correction processing of the digital watermark pattern generated by the digital watermark pattern generating means is executed based on the predicted value.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, when the input signal to be subjected to the digital watermark pattern embedding processing is an image signal, the signal control means performs a data conversion process on the image signal. A deterioration state of the input signal is predicted for each predetermined area of the image signal, and a correction process of the digital watermark pattern generated by the digital watermark pattern generation unit is executed based on the predicted value. And

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, when the input signal to be subjected to the digital watermark pattern embedding processing is an image signal, the signal control means performs a data conversion process on the image signal. A deterioration state of the input signal based on the image signal is predicted for each pixel of the image signal, and a correction process of the digital watermark pattern generated by the digital watermark pattern generation unit is performed based on the predicted value. I do.

Further, in one embodiment of the digital watermark embedding processing device of the present invention, the signal control means predicts a deterioration state of the input signal based on a data conversion process for the input signal to be subjected to the digital watermark pattern embedding process, Based on the predicted value, for the digital watermark pattern generated by the digital watermark pattern generating means, reduce the embedding level of the digital watermark information for a signal region determined to be largely deteriorated by the data conversion process;
It is characterized in that a correction process for increasing the embedding level of digital watermark information is executed for a signal region determined to be less deteriorated by the data conversion process.

Further, in one embodiment of the digital watermark embedding processing device of the present invention, the signal control means calculates, as an absolute value, a difference between the processing data after the data conversion processing on the input signal and the input signal. Difference calculation means, based on the absolute value output by the difference calculation means,
The present invention is characterized in that a deterioration state of an input signal is predicted, and a correction process of the digital watermark pattern generated by the digital watermark pattern generating means is executed based on the prediction.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the signal control means calculates, as an absolute value, a difference between the processing data after the data conversion processing on the input signal and the input signal. Difference calculating means, and a signal area in which the absolute value output by the difference calculating means is larger than a predetermined threshold value is determined to have a large deterioration due to the data conversion processing, and a digital watermark is applied to the signal area. The signal embedding level of the information is reduced, and it is determined that the signal area whose absolute value is smaller than a predetermined threshold value has little deterioration due to the data conversion processing, and the embedding of digital watermark information is performed on the signal area. It is characterized in that it is configured to execute a correction process for increasing the level.

Further, in one embodiment of the digital watermark embedding processing device of the present invention, the signal control means has a positive / negative sign for a difference between the processing data after the data conversion processing on the input signal and the input signal. A difference calculating means for calculating the value as a value, and predicting a deterioration state of the input signal based on a value output from the difference calculating means, and correcting the digital watermark pattern generated by the digital watermark pattern generating means based on the prediction. It is characterized in that it is configured to execute processing.

Further, in one embodiment of the digital watermark embedding processing device of the present invention, the signal control means has a positive / negative sign for a difference between the processing data after the data conversion processing on the input signal and the input signal. A difference calculating means for calculating as a value, and a value output by the difference calculating means,
If the value of the digital watermark pattern generated by the digital watermark pattern generating means is the same as that of the digital watermark pattern, the digital watermark pattern is corrected as it is or the level is increased. When the value of the digital watermark pattern generated by the digital watermark pattern generating means is different from that of the digital watermark pattern, the value of the digital watermark pattern is set to 0 or the level is reduced to execute a correction. .

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the signal control means executes a word length conversion on the input signal, and executes a process of truncating low-order bits of each value of the input signal. Result data Da
Compare the difference between (DV1) and the result data Db (DV1 + WM) obtained by executing a process of removing the low-order bit of each value of the added signal obtained by adding the digital watermark pattern generated by the digital watermark pattern generation means to the input signal. Then D
If a (DV1) = Db (DV1 + WM), it is determined that the digital watermark pattern WM is deteriorated or lost due to the word length conversion. If Da (DV1) ≠ Db (DV1 + WM), the digital watermark pattern WM is the word An area that is determined not to deteriorate or disappear by the length conversion, the level of the digital watermark pattern of the area determined to deteriorate or disappear by the word length conversion is reduced or set to 0, and an area determined not to deteriorate or disappear by the word length conversion Wherein the correction for increasing the level of the digital watermark pattern is performed.

Further, in one embodiment of the digital watermark embedding processing device of the present invention, the digital watermark pattern generating means has a signal modulating means for modulating a digital watermark pattern initially generated based on the analysis of the input signal. The signal control means is configured to execute a correction process of a digital watermark pattern output from the signal modulation means.

Further, a second aspect of the present invention is a digital watermark embedding method for executing a digital watermark embedding process, the digital watermark pattern generating step of generating a digital watermark pattern based on the embedded information, and a digital watermark pattern generating step. Predict the degradation state of the input signal based on the data conversion processing for the input signal to be subjected to pattern embedding processing,
A signal control step of executing a correction process of the digital watermark pattern generated in the digital watermark pattern generation step based on the predicted value; and a process of embedding the digital watermark pattern corrected in the signal control step in the input signal. A digital watermark embedding processing method.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the signal control step includes:
As the data conversion processing, a compression / expansion processing step of executing a compression / expansion processing on the input signal, processing data after the compression / expansion processing on the input signal generated in the compression / expansion processing step, and a difference between the input signal and A difference calculating step of calculating, and a signal correcting step of executing a correction process of the digital watermark pattern generated in the digital watermark pattern generating step based on the difference data output in the differential calculating step. .

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the signal control step includes:
An encoding / decoding processing step of executing an encoding / decoding processing on the input signal as the data conversion processing;
Processing data obtained by performing the encoding / decoding processing on the input signal generated in the encoding / decoding processing step, a difference calculation step of calculating a difference between the input signal, and a difference data output in the difference calculation step. A signal correcting step of executing a correction process of the digital watermark pattern generated in the digital watermark pattern generating step.

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the signal control step includes:
As the data conversion processing, MP for the input signal
An encoding / decoding process for executing an encoding / decoding process based on EG2; a difference between the input signal and the processed data after the encoding / decoding process for the input signal generated in the encoding / decoding process step; And a signal correction step of performing a correction process on the digital watermark pattern generated in the digital watermark pattern generation step based on the difference data output in the difference calculation step. I do.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the signal control step includes:
As the data conversion processing, a word length conversion processing step of performing a word length conversion processing on the input signal; processing data after the word length conversion processing on the input signal generated in the word length conversion processing step; And a signal correction step of performing a correction process on the digital watermark pattern generated in the digital watermark pattern generation step based on the difference data output in the difference calculation step. It is characterized by.

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the signal control step includes:
The degradation state of the input signal based on the data conversion processing for the input signal to be subjected to the digital watermark pattern embedding processing is
A step of performing prediction for each predetermined unit data of the input signal and executing a correction process of the digital watermark pattern generated in the digital watermark pattern generation step based on the predicted value.

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the signal control step includes:
When the input signal to be subjected to the digital watermark pattern embedding processing is an image signal, the deterioration state of the input signal based on the data conversion processing for the image signal is predicted for each predetermined area of the image signal, and based on the predicted value. And performing a correction process on the digital watermark pattern generated in the digital watermark pattern generating step.

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the signal control step includes:
When the input signal to be subjected to the electronic watermark pattern embedding processing is an image signal, the deterioration state of the input signal based on the data conversion processing for the image signal is predicted for each pixel of the image signal, and based on the predicted value, A step of executing a correction process of the digital watermark pattern generated in the digital watermark pattern generating step.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the signal control step includes:
A deterioration state of an input signal is predicted based on a data conversion process for an input signal to be subjected to a digital watermark pattern embedding process, and the data conversion process is performed on the digital watermark pattern generated in the digital watermark pattern generation step based on the predicted value. The embedding level of digital watermark information is reduced for signal regions determined to be largely degraded by the data conversion, and the embedding level of digital watermark information is increased for signal regions determined to be small due to the data conversion process. And performing a correction process.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the signal control step includes:
A difference calculation step of calculating a difference between the processed data after the data conversion processing on the input signal and the input signal as an absolute value, and predicting a deterioration state of the input signal based on the absolute value output in the difference calculation step And performing a correction process on the digital watermark pattern generated in the digital watermark pattern generating step based on the prediction.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the signal control step includes:
A difference calculation step of calculating a difference between the processing data after the data conversion processing on the input signal and the input signal as an absolute value, and an absolute value output in the difference calculation step is larger than a predetermined threshold value The signal area is determined to be largely deteriorated by the data conversion processing,
The embedding level of the digital watermark information is reduced for the signal area, and the signal area whose absolute value is smaller than a predetermined threshold value is determined to be less deteriorated by the data conversion processing. And performing a correction process for increasing the embedding level of the digital watermark information.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the signal control step includes:
A difference calculating step of calculating a difference between the processed data after the data conversion processing on the input signal and the input signal as a value having a positive / negative sign; and a deterioration of the input signal based on the value output in the difference calculating step. Predicting a situation, and executing a correction process of the digital watermark pattern generated in the digital watermark pattern generating step based on the prediction.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the signal control step includes:
Processing data after the data conversion processing on the input signal, a difference calculation step of calculating a difference between the input signal and the input signal as a value having a positive or negative sign, the value output in the difference calculation step, the digital watermark pattern generation step If the value of the digital watermark pattern is the same as the value of the digital watermark pattern generated in step 2, the digital watermark pattern is corrected as it is or the level is increased. When the value of the digital watermark pattern is different from the value of the generated digital watermark pattern, the value of the digital watermark pattern is set to 0 or the level is reduced.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the signal control step includes:
The digital watermark pattern generated in the digital watermark pattern generation step is added to data Da (DV1) obtained by performing word length conversion on the input signal and performing a process of truncating low-order bits of each value of the input signal. Are compared with the result data Db (DV1 + WM) obtained by performing the process of rounding down the low-order bit of each value of the addition signal obtained by adding the digital watermark pattern WM. It is determined that the signal is degraded or lost by the length conversion, and Da (DV1) ≠ Db (D
V1 + WM), it is determined that the digital watermark pattern WM does not deteriorate or disappear due to the word length conversion, and the level of the digital watermark pattern in the area determined to deteriorate or disappear due to the word length conversion is reduced or the value is set to 0. The method includes a step of performing a correction for increasing the level of a digital watermark pattern in a region determined not to be deteriorated or lost by the word length conversion.

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the digital watermark pattern generating step includes a signal modulation step of modulating a digital watermark pattern initially generated based on the analysis of the input signal. The signal control step includes a step of executing a correction process of a digital watermark pattern output in the signal modulation step.

Further, a third aspect of the present invention is a program for executing a digital watermark pattern embedding process on a computer system, the digital watermark pattern generating step for generating a digital watermark pattern based on the embedded information, A deterioration state of an input signal is predicted based on a data conversion process for an input signal to be subjected to a digital watermark pattern embedding process, and a correction process of the digital watermark pattern generated in the digital watermark pattern generation step is performed based on the predicted value. A signal control step;
An addition step of executing a process of embedding the digital watermark pattern corrected in the signal control step into the input signal.

The program of the present invention is provided, for example, in a computer-readable medium to a general-purpose computer system capable of executing various program codes, for example, a storage medium such as a CD, an FD, and an MO. The program of the present invention can be stored in a medium that provides a computer program in a computer-readable format for a general-purpose computer system that can execute various program codes, for example. is there. The form of the medium is not particularly limited, such as a recording medium such as a CD, an FD, and an MO, and a transmission medium such as a network.

Such a program regulates the execution of various functions of the system based on the reading of the program under the control of the processor, and exerts a cooperative action on the system. The same operation and effect as those of the aspect can be obtained.

Still other objects, features and advantages of the present invention are:
It will become apparent from the following more detailed description based on the embodiments of the present invention and the accompanying drawings.

[0098]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a digital watermark embedding processing apparatus and a digital watermark embedding processing method according to the present invention will be described in detail with reference to the drawings.

[Configuration Example 1 of Digital Watermark Embedding Processing Apparatus]
FIG. 6 is a block diagram showing a digital watermark embedding processing device 100 according to one embodiment of the present invention. In the digital watermark embedding processing device 100, the PN generation unit 121
(Pseudorandom Noise; pseudo-noise code) sequence random number data PN is generated, and a digital watermark is embedded using this as a basic pattern. The subsequent multiplying unit 122 spectrum-spreads the digital watermark embedding information DC using the random number data PN, and spreads the spread digital watermark information DC with the digital watermark pattern WM1.
And By spreading the embedded information DC in a spectrum using the random number data PN, a digital watermark pattern WM1 that is difficult to analyze can be generated. In the configuration of FIG. 6, the PN generation unit 121 and the multiplication unit 122 configure a first digital watermark pattern generation unit for generating the digital watermark pattern WM1.

The digital watermark embedding information DC is, for example, “copy free”, “copy once”, “absolute copy prohibition” (copy free) as copy control information in accordance with the digital watermark embedding target signal. N
ever Copy) "and the like.

In the digital watermark embedding processing apparatus 100, the image analysis unit 123 performs image analysis on the sequentially input digital video signal DV1 in consideration of human visual characteristics, and outputs image analysis information P. These image analyzes include those that redistribute a digital watermark pattern in an image in consideration of human visual characteristics and those that cause a digital watermark pattern to follow the movement of an image.

For example, utilizing the fact that the human eye is sensitive to changes in a low-frequency region such as a flat portion, but insensitive to changes in a high-frequency region such as an edge portion, the digital watermark pattern is conspicuous. In the case of redistribution from an easily flat portion to an inconspicuous edge portion, the image analysis section 123 is constituted by an edge detection section and the like, and outputs edge information and the like as image analysis information P. Also, when the image is stationary, the digital watermark pattern is also stopped, and when the image is moving, the digital watermark pattern is also moved.
When embedding a digital watermark so as to make it difficult for human eyes to perceive, the image analysis unit 123 is configured by a motion detection unit and the like, and outputs motion information and the like as the image analysis information P.
Thus, the influence of the digital watermark on the image quality can be effectively suppressed without changing the overall embedding strength.

The signal modulator 124 modulates the digital watermark pattern WM1 based on the image analysis information P output from the image analyzer 123, and outputs a digital watermark pattern WM2 in consideration of human visual characteristics. For example, when the image analysis information P is configured by edge information or the like, the signal modulation unit 124 is configured by a multiplication unit or the like that modulates the digital watermark pattern WM1 with edge information or the like. When the image analysis information P is composed of motion information or the like, the signal modulating unit 124 is composed of a motion follower that causes the digital watermark pattern WM1 to follow an image based on motion information or the like. In the configuration of FIG. 6, the image analysis unit 123 and the signal modulation unit 124 constitute a second digital watermark pattern generation unit for generating the digital watermark pattern WM2 based on the digital watermark pattern WM1.

Next, the signal controller 125 applies the digital watermark pattern WM2 output from the signal modulator 124 to
It is determined for each image area whether or not the digital watermark pattern WM2 is deteriorated by data conversion processing such as encoding and word length conversion on the image, and the amount of deterioration of the input digital video signal DV1 due to the data conversion processing of the image is large. If it is determined that there is an image area in which it becomes difficult to detect a digital watermark due to the data conversion process, a digital watermark pattern WM3 with enhanced resistance to image data processing such as encoding and word length conversion is generated. Output. That is, the signal control unit 125 performs some kind of data processing such as encoding and word length conversion on the input digital video signal DV1, and measures the influence of the data conversion processing on the embedded digital watermark as the amount of deterioration.

In the signal control unit 125, the data in which the input digital video signal DV 1 has a small deterioration amount due to the image data conversion process is small, and the data in which the digital watermark pattern WM 2 from the signal modulation unit 124 is embedded is subjected to image processing such as compression. If it is determined that the digital watermark does not affect the detection of the digital watermark, the signal control unit 125 outputs the digital watermark pattern WM2 output from the signal modulation unit 124 to the addition unit 126. Signal DV
1 and the digital watermark pattern WM2, the digital watermark information D1 is added to the input digital video signal DV1.
The embedding process of the digital watermark pattern WM2 having C is executed.

On the other hand, if the signal control unit 125 determines that the amount of deterioration of the input digital video signal DV1 due to the data processing of the image is so great that the detection of the digital watermark becomes difficult by the data processing, the encoding and the word length are performed. The digital watermark pattern WM3 with enhanced resistance to image data processing such as conversion is output to the adding unit 126, and the adding unit 126 adds the digital watermark pattern WM3 to the input digital video signal DV1 to thereby add to the input digital video signal DV1. The embedding process of the digital watermark pattern WM3 having the digital watermark information DC is performed.

The digital watermark pattern WM3 output from the signal control unit 125 and having enhanced resistance avoids embedding a digital watermark pattern in a region that is degraded by image processing, and reduces the amount of embedding that has been avoided to a portion that is not degraded by image processing. This is a digital watermark pattern obtained as a result of redistributing the allocated and surplus embedding amount in the image.

By executing such a process of embedding the digital watermark pattern WM3, it is possible to reduce the surplus embedding amount which affects the image quality but does not contribute to the reliability of detection.

As described above, the digital watermark embedding processing apparatus of the present invention shown in FIG. 6 executes encoding, word length conversion processing, and the like for data to be embedded with digital watermarks, and obtains a digital watermark as a data deterioration amount due to the processing. Is measured, and when the degree of the effect is large, a process for embedding the digital watermark pattern WM3 with enhanced resistance to the data conversion process is performed. Even if processing such as word length conversion is executed, it is possible to reliably detect a digital watermark, and it is also possible to reduce a surplus embedding amount that affects image quality but does not contribute to detection reliability.

[Configuration Example 1 of Signal Control Unit] FIG. 7 is a block diagram showing a first configuration example of the signal control unit 125 in the digital watermark embedding processing apparatus 100. Signal control unit 1
At 25, the compression / expansion unit 127 executes image encoding / decoding processing such as MPEG2 on the input digital video signal DV1, and outputs a compressed digital video signal and an expanded digital video signal DV1 '. Here,
Although the compression / expansion processing is described as being synonymous with the image encoding / decoding processing, the configuration may be such that encoding / decoding processing without compression / expansion is performed. In this case, the compression / expansion unit 127 in FIG. , As an encoding / decoding unit.

The difference calculator 128 calculates the difference between the input digital video signal DV1 before the encoding / image decoding process, that is, the compression / expansion process, and the digital video signal DV1 ′ after the compression / expansion process output from the compression / expansion unit 127. Is calculated, and the difference information D is output. That is, the difference calculator 128 outputs a calculation result by the following equation.

[0112]

D = | DV1-DV1 '|

The difference information D represents a predicted deterioration amount from the original input digital video signal DV1 due to the compression / expansion processing executed as the image encoding / decoding, and the value of the difference information D is equal to the threshold value TH ( D), the deterioration of the corresponding pixel in the input digital video signal DV1 due to the image encoding / decoding process is small, and the difference information D
Is larger than the threshold value TH (D), it is determined that the deterioration of the corresponding pixel in the input digital video signal DV1 due to the image encoding / decoding process is large. The difference information D is calculated for a predetermined unit area of the image, for example, for each pixel,
The deterioration amount is determined for each area.

The signal correction unit 129 determines whether or not to perform the correction processing of the digital watermark pattern WM2 based on each difference information D for each area output from the difference calculation unit 128, and if necessary, determines whether or not the correction processing of the digital watermark pattern WM2 is performed. Execute the correction process,
An electronic watermark pattern WM3 with enhanced resistance to image encoding is output. For example, when each value of the digital watermark pattern WM2 is degraded by image coding based on the difference information D, avoiding the embedding of the digital watermark pattern can affect the image quality but does not contribute to the reliability of detection. The amount of embedding can be reduced. Furthermore, by assigning the avoided embedding amount to a portion that is not degraded by image encoding, it becomes possible to redistribute the surplus embedding amount in the image and more efficiently embed digital watermark information.

FIG. 8 is a schematic diagram for explaining the relationship between the embedding level and the amount of deterioration due to image coding. Conventionally, when embedding digital watermark information in an image signal, the digital watermark embedding process is performed at a uniform intensity (level) without determining which region is deteriorated by image encoding. That is, the embedding level of the electronic watermark is embedded in each area with a uniform distribution as shown by a dotted line in FIG. As a result, the digital watermark information embedded in a certain pixel is hardly affected by the image coding, but the digital watermark information embedded in another pixel is greatly deteriorated by the image coding.

In the digital watermark embedding processing apparatus according to the present invention, D = │DV1-DV
1 ′ |, the data compression / decompression processing, for example, MPEG2
And the like, the effect on the image encoding process is calculated in an image region, for example, in units of pixels, and in a region (pixel) having a large amount of deterioration due to the image processing, a process of reducing the embedding level or to 0 is executed, and the deterioration due to the image processing is performed. In a small area (pixel), an adjustment to increase the embedding level is performed to generate a corrected digital watermark pattern WM3 and embed a digital watermark.

The relationship between the embedding level after the execution of the adjustment processing and the amount of deterioration due to image coding is, for example, a distribution shown by a solid line in FIG. With such correction, digital watermark information can be embedded so as to avoid the influence of deterioration due to image coding. That is, using the difference information D as an index, the embedding level of the digital watermark information is reduced for pixels that are greatly deteriorated by image coding,
The embedding level of the digital watermark information may be increased for a pixel having a small deterioration due to the image coding. This reduces the amount of surplus embedding that does not contribute to the reliability of detection when passing through image encoding while affecting image quality, and furthermore, redistributes the avoided amount of embedding in the image, and By controlling the embedding strength to a certain amount, it is possible to enhance the resistance to image coding and secure the reliability of digital watermark detection.

The signal correction section 129 of the signal control section 125 shown in FIG.
M3 is generated and output to the adding unit 126 (see FIG. 6).
The adder 126 adds the digital watermark pattern WM3 output from the signal controller 125 to the input digital video signal DV1.
Are added to obtain the input digital video signal DV1.
And outputs a digital video signal DV2 in which the digital watermark information DC is embedded in the same format as the above.

The output digital video signal DV2 is encoded by a predetermined encoder, for example, and transmitted from a broadcasting station or the like via a medium such as a satellite wave, a terrestrial wave, or a cable. Alternatively, the output digital video signal DV
2 is encoded by a predetermined encoder to expose the master disc, and the optical disc 8 and the like are mass-produced from the master disc.

As described above, the digital watermark pattern WM3
Is a digital watermark pattern corrected in consideration of the influence of encoding. Even in encoded (encoded) data, the degradation of the digital watermark is reduced, and the digital watermark pattern can be reliably detected in the digital watermark detection process during reproduction and copying. , The detection of the digital watermark is executed.

[Configuration Example 2 of Signal Control Unit] FIG. 9 shows a second example of the signal control unit 125 in the digital watermark embedding processing apparatus 100.
FIG. 3 is a block diagram illustrating a configuration example. In the signal control unit 125, the adding unit 130 once adds the digital watermark pattern WM2 to the input digital video signal DV1, and outputs the added digital video signal DV3.

The following compression / expansion unit 131 adds the
Performs an image encoding / decoding of the digital watermark added digital video signal DV3 output by, for example, MPEG2, and outputs a compressed / expanded digital video signal DV3 ′. Subsequent difference calculation section 132 receives input digital video signal D
The difference between V1 and the compressed / expanded digital video signal DV3 'output by the compression / expansion unit 131 is calculated, and difference information D is output. That is, the difference calculator 132 outputs a calculation result by the following equation.

[0123]

D = DV3'-DV1

The difference information D is a digital watermark pattern W obtained by performing image coding on an image in which a digital watermark is embedded.
It represents the expected remaining amount of M2. This difference information D
Is calculated for a predetermined unit area of the image, for example, for each pixel, and the deterioration amount is determined for each area.

In the above [Equation 13], for example, MP
The difference between the compressed / expanded digital video signal DV3 'obtained as a result of performing the image encoding / decoding of the image such as EG2 and the input digital video signal DV1 is used as the difference information. Similarly, for the compressed / decompressed digital video signal DV1 ', which has been once subjected to image encoding / decoding such as MPEG2 and output, and the digital watermark-added digital video signal DV3, for example, MPE
A difference from the compressed / decompressed digital video signal DV3 ′ obtained as a result of performing image encoding / decoding of G2 or the like may be obtained as difference information. That is, the difference calculator 132 outputs a calculation result by the following equation.

[0126]

D = DV3'-DV1 '

The difference information D includes a predetermined unit area of the image,
For example, it is calculated for each pixel, and the deterioration amount is determined for each region.

The signal correction unit 133 is provided with the difference calculation unit 13
2 determines whether or not to perform the correction processing of the digital watermark pattern WM2 based on the difference information D output from the digital watermarking apparatus 2, and executes the correction processing of the digital watermark pattern WM2 as necessary, thereby enhancing the resistance to image encoding. Pattern WM3
Is output.

For example, each value of the digital watermark pattern WM2 (for example, see WM having a value as shown in [Equation 2]) is equal to each value of the difference information D shown in the above [Equation 13] or [Equation 14]. A code data area (for example, a pixel as an image area) means that each value of the digital video signal DV1 changes in the same polarity direction as each value of the digital watermark pattern WM2 by image coding. It is determined that the detection of the digital watermark pattern is unlikely to be difficult, and the digital watermark pattern is added as it is. Or increase the level and add.

On the other hand, a data area (for example, a pixel as an image area) in which each value of the digital watermark pattern WM2 and each value of the difference information D shown in the above formula [Equation 13] or [Equation 14] have different codes, is Digital video signal DV by encoding
Since each value of 1 means that the value of the digital watermark pattern WM2 changes in a direction of a different polarity from the value of the digital watermark pattern WM2, it is determined that the detection of the digital watermark pattern is likely to be difficult due to the image encoding. Avoid embedding. Or decrease the level. In order to avoid embedding a digital watermark pattern, the value of the digital watermark pattern may be set to 0.

The signal correction section 133 of the signal control section 125 shown in FIG.
M3 is generated and output to the adding unit 126 (see FIG. 6).
The adder 126 adds the digital watermark pattern WM3 output from the signal controller 125 to the input digital video signal DV1.
Are added to obtain the input digital video signal DV1.
And outputs a digital video signal DV2 in which the digital watermark information DC is embedded in the same format as the above.

Thus, the digital watermark pattern WM3
Is a digital watermark pattern corrected in consideration of the influence of encoding. Even in encoded (encoded) data, deterioration of the digital watermark is reduced, and the digital watermark detection processing at the time of reproduction and duplication is ensured. The detection of a digital watermark is executed in the first step, and the surplus embedding amount that affects the image quality but does not contribute to the reliability of the detection can be reduced.

[Configuration Example 3 of Signal Control Unit] FIG. 10 is a block diagram showing a third configuration example of the signal control unit 125 in the digital watermark embedding processing apparatus 100. In the signal control unit 125, the comparison determination unit 137 adds the digital watermark pattern WM2 to the input digital video signal DV1, and determines the influence on the digital watermark when, for example, a word length conversion process from 10 bits to 8 bits is performed. , And outputs the determination information C to the signal correction unit 138.

For example, when determining the influence on the digital watermark when the word length conversion processing is performed from 10 bits to 8 bits, the comparison determination unit 137 determines the LSB side of each pixel value of the input digital video signal DV2 as 2 bits ( Data Da obtained by executing the process of truncating (see FIG. 4)
(DV1), the LSB of each pixel value of the added data of the input digital video signal DV1 and the digital watermark pattern WM2
Compare the difference with the data Db (DV1 + WM2) obtained by executing the process of discarding the two bits (refer to FIG. 4). If Da (DV1) = Db (DV1 + WM2), the digital watermark pattern WM2 has the word length. It is determined that the digital watermark pattern WM2 is deteriorated or lost by the conversion, and if Da (DV1) ≠ Db (DV1 + WM2), it is determined that the digital watermark pattern WM2 is not deteriorated or lost by the word length conversion. The determination information C by the difference comparison processing is calculated for each predetermined unit area of the image, for example, for each pixel, and the deterioration amount due to the word length conversion is determined for each area.

The signal correction unit 138 determines whether or not to perform the correction processing of the digital watermark pattern WM2 based on the comparison determination information C for each area output from the comparison and determination unit 137. A correction process is executed to output a digital watermark pattern WM3 with enhanced resistance to image coding. For example, a digital watermark pattern WM
2 is determined to be degraded (disappeared) by word length conversion based on the determination information C, the level of the value of the corresponding region is reduced or the value is replaced with 0 to reduce the embedding of the digital watermark or By avoiding and correcting the digital watermark pattern by increasing the level of the value of the corresponding region in the region determined not to deteriorate (disappear) by the word length conversion,
The surplus embedding amount that affects image quality but does not contribute to the reliability of detection can be reduced, and the surplus embedding amount can be reduced by assigning the avoided embedding amount to a portion that does not deteriorate (disappear) by word length conversion. Redistribution within an image allows more efficient embedding of digital watermark information.

The signal correction section 138 of the signal control section 125 shown in FIG. 10 generates such a corrected digital watermark pattern WM3 and outputs it to the addition section 126 (see FIG. 6). The adder 126 adds the digital watermark pattern W output from the signal controller 125 to the input digital video signal DV1.
By adding M3, the input digital video signal D
A digital video signal DV2 in which digital watermark information DC is embedded in the same format as V1 is output.

The output digital video signal DV2 is encoded by a predetermined encoder, for example, and transmitted from a broadcast station or the like via a medium such as a satellite wave, a terrestrial wave, or a cable. Alternatively, the output digital video signal DV
2 is encoded by a predetermined encoder to expose the master disc, and the optical disc 8 and the like are mass-produced from the master disc.

As described above, the digital watermark pattern WM3
Is a digital watermark pattern corrected in consideration of the influence of word length conversion.Even if word length conversion is performed after embedding a digital watermark, deterioration of the digital watermark is reduced, In the digital watermark detection processing in the above, the detection of the digital watermark is surely executed.

[Digital Watermark Embedding Processing Apparatus Configuration Example 2]
FIG. 11 is a block diagram showing a configuration example 2 of the digital watermark embedding processing device 100. In the digital watermark embedding processing device 100, the PN generation unit 141 generates PN sequence random number data PN and embeds a digital watermark using this as a basic pattern. The subsequent multiplying unit 142 spreads the spectrum of the digital watermark embedding information DC by using the random number data PN, and sets it as a digital watermark pattern WM1. By spreading the embedded information DC in a spectrum using the random number data PN, a digital watermark pattern WM1 that is difficult to analyze can be generated.

The digital watermark embedding information DC is, for example, as copy control information, in accordance with the digital watermark embedding target signal, “copy free (Copy Free)”, “copy once (Copy Once)”, “absolute copy prohibition ( N
ever Copy) "and the like.

In the digital watermark embedding apparatus 100, the image analyzer 143 performs image analysis on the sequentially input digital video signal DV1 in consideration of human visual characteristics, and outputs image analysis information P. These image analyzes take into account the human visual characteristics, such as redistributing the digital watermark pattern in the image, and making the digital watermark pattern follow the movement of the image, etc., thereby changing the overall embedding strength. Therefore, the effect of the digital watermark on the image quality can be effectively suppressed.

The signal modulation section 144 modulates the digital watermark pattern WM1 based on the image analysis information P output from the image analysis section 143, and outputs a digital watermark pattern WM2 in consideration of human visual characteristics. For example, when the image analysis information P is configured by edge information or the like, the signal modulation unit 144 is configured by a multiplication unit that modulates the digital watermark pattern WM1 with edge information or the like. When the image analysis information P is composed of motion information or the like, the signal modulator 144 is composed of a motion follower that follows the digital watermark pattern WM1 with an image based on the motion information or the like.

Next, the signal control unit 145 applies the digital watermark pattern WM2 output from the signal modulation unit 144 to the digital watermark pattern WM2.
By judging whether or not the digital watermark pattern WM2 is deteriorated by data processing such as image encoding and word length conversion, the digital video signal DV2 in which the digital watermark information DC is embedded by enhancing the resistance to the data conversion processing is output. I do.

That is, the signal control unit 145 once performs data processing such as image encoding / decoding and word length conversion on the input digital video signal DV1 to thereby reduce the influence on image degradation and digital watermark due to the data processing. Predict and input digital video signal DV1 by data processing
Is determined to have the same polarity as the digital watermark pattern WM2, it is determined that the digital watermark is not deteriorated due to the data processing, and the digital watermark pattern WM2 is added to the input digital video signal DV1. Digital watermark information DC1 is embedded in digital video signal DV1, and digital video signal DV2 in which digital watermark information DC is embedded is output.

On the other hand, when the change in the input digital video signal DV1 due to data processing such as image encoding and word length conversion has a polarity opposite to that of the digital watermark pattern WM2, it is determined that the digital processing has significantly deteriorated the digital watermark. ,Coding,
By generating a digital watermark pattern WM3 with enhanced resistance to image data processing such as word length conversion and adding the digital watermark pattern WM3 to the input digital video signal DV1, the digital watermark information DC is embedded in the input digital video signal DV1, The digital video signal DV2 in which the digital watermark information DC is embedded is output.

FIG. 12 is a block diagram showing a configuration example of the signal control unit 145 in the digital watermark embedding processing apparatus 100 shown in FIG. In the signal control section 145, the compression / expansion section 146 performs M conversion on the input digital video signal DV1.
It performs image encoding / decoding of PEG2 or the like and outputs a compressed / expanded digital video signal DV1 '. The following difference calculation unit 147 includes an input digital video signal DV1 and a compressed / expanded digital video signal DV output by the compression / expansion unit 146.
1 ′, and outputs difference information D. That is, the difference calculator 147 outputs a calculation result by the following equation.

[0147]

D = DV1-DV1 '

This difference information D indicates the amount and direction of the predicted deterioration from the original input digital video signal DV1 due to the image coding.

The signal correction section 148 is provided for the difference calculation section 14.
7, the digital watermark pattern WM2 is corrected based on the difference information D output, and a digital watermark pattern WM3 with enhanced resistance to image encoding is output.

For example, each value of the digital watermark pattern WM2 (for example, WM having a value shown in [Equation 2]) and each value of the difference information D shown in the above [Equation 15] are the same in the data area (for example, (Pixel as an image area) means that each value of the digital video signal DV1 changes in the direction of the same polarity as each value of the digital watermark pattern WM2 by the image coding, and the detection of the digital watermark pattern by the image coding. It is determined that there is little risk of becoming difficult, and the digital watermark pattern is added as it is.

On the other hand, a data area (for example, a pixel as an image area) in which each value of the digital watermark pattern WM2 and each value of the difference information D shown in the above formula [Equation 15] have different codes is converted into a digital video by image coding. Since each value of the signal DV1 changes in a direction of a different polarity from each value of the digital watermark pattern WM2, it is determined that the detection of the digital watermark pattern is likely to be difficult due to the image encoding. Avoid embedding.

The signal correction section 148 of the signal control section 145 shown in FIG. 12 generates such a corrected digital watermark pattern WM3 and outputs it to the addition section 149. Adder 14
9 outputs a digital video signal DV2 in which digital watermark information DC is embedded in the same format as the input digital video signal DV1 by adding the digital watermark pattern WM3 output from the signal control unit 148 to the input digital video signal DV1. I do.

The output digital video signal DV2 is encoded by a predetermined encoder, for example, and transmitted from a broadcasting station or the like via a medium such as a satellite wave, a terrestrial wave, or a cable. Alternatively, the output digital video signal DV
2 is encoded by a predetermined encoder to expose the master disc, and the optical disc 8 and the like are mass-produced from the master disc.

As described above, the digital watermark pattern WM3
Is a digital watermark pattern corrected in consideration of the influence of encoding. Even in encoded (encoded) data, the degradation of the digital watermark is reduced, and the digital watermark pattern can be reliably detected in the digital watermark detection process during reproduction and copying. , The detection of the digital watermark is executed.

[Digital Watermark Embedding Processing Flow]
The processing procedure in the digital watermark embedding processing device of the present invention will be described with reference to the flow shown in FIG. FIG. 13 shows a digital watermark embedding processing apparatus that executes a digital watermark pattern embedding process for an input signal such as a digital video signal, for example, in which the resistance to various data processes such as compression, encoding, and word length conversion is enhanced. It is a flowchart which shows a processing procedure. Each step will be described.

First, in step S11, the digital watermark embedding processing device generates PN sequence random number data.
In step S12, according to the digital watermark embedding target signal, “copy permitted (Copy Free)”, “copy permitted once (Copy Once)”, “absolute copy prohibited (N
embedded copy, such as copy control information, is spectrum-spread with random number data PN to generate a digital watermark pattern WM1.

Subsequently, in step SP13, the digital watermark embedding apparatus sequentially reads the input signal (for example, the digital video signal DV1), and in step S14, analyzes the input signal in consideration of human visual characteristics and auditory characteristics. And output the analysis information. For example, if the input signal is an image, in consideration of the visual characteristics of human beings, the analysis is performed by redistributing the digital watermark pattern in the image, or by causing the digital watermark pattern to follow the movement of the image. For example, this is a process of performing image analysis such as edge detection and motion detection on an input digital video signal, and outputting edge information and motion information as image analysis information.

Subsequently, in step S15, the digital watermark embedding processing device modulates the digital watermark pattern WM1 based on the analysis information, and generates a digital watermark pattern WM2 in consideration of human visual characteristics and auditory characteristics. These signal modulations include, for example, when the input signal is an image, the digital watermark pattern WM1 is modulated by edge information or the like, or the digital watermark pattern WM1 is made to follow an image by motion information or the like.

Subsequently, in step S16, the digital watermark embedding apparatus compresses, encodes,
Perform processing such as word length conversion. These processes are preferably performed assuming processes to be performed after the digital watermark is embedded in the input signal. For example, if the data compression process of MPEG2 is to be applied, MPEG2 compression is performed. If there is a plan to execute the word length conversion process from 10 bits to 8 bits, the word length conversion process is executed. Note that these different plural data conversion processes may be sequentially executed.

Subsequently, the digital watermark embedding processing apparatus proceeds to step S17, calculates a difference between the input signal before data processing and the processed data, and outputs difference information D. The process of generating the difference information is performed in any manner such as a method of obtaining the absolute value of [Equation 12] and a process of obtaining the difference as a difference having a positive or negative sign.

Subsequently, in step SP18, the digital watermark embedding processing device corrects each value of the digital watermark pattern WM2 based on the difference information D, and generates a digital watermark pattern WM3 with enhanced resistance to image coding. In other words, based on the difference information D, the digital watermark pattern WM2 is placed in an area (for example, a pixel in the case of image data) where deterioration due to data processing such as encoding and word length conversion is large.
The digital watermark pattern WM3 is generated by performing a correction by increasing the embedment level of the digital watermark pattern WM2 in an area where deterioration due to data processing such as encoding and word length conversion is small, by reducing the embedment level of the digital watermark pattern WM3. ,
An electronic watermark pattern WM3 with enhanced resistance to data processing such as word length conversion is output.

Subsequently, the digital watermark embedding processing apparatus proceeds to step S19, adds the corrected digital watermark pattern WM3 to the input signal, and in the next step S20, converts the signal in which the digital watermark information is embedded in the same format as the input signal. Is output.

Subsequently, in step S21, the digital watermark embedding processing device determines whether or not the processing of the input signal has been completed. If a negative result is obtained here, step S13 is performed.
And the following processing is repeatedly executed. The digital watermark embedding processing device sequentially processes the input signal by repeating the same process for the input signal, and completes the process when a positive result is obtained in the determination of the end of the input in step S21.

The processing of steps S16 to S18 in the processing flow of FIG. 13, that is, the processing of executing data conversion processing on an input signal and correcting a digital watermark based on the difference D obtained as a processing result is various. Various data processing, that is, encoding, compression, word length conversion, and the like may be individually and repeatedly executed. For example, MPEG2 compression and decompression are performed as first data processing to obtain a difference D1, a digital watermark pattern WM3 corrected based on the difference D1 is generated, and word length conversion is performed as second data processing. Then, a difference D2 is obtained, and a digital watermark pattern WM4 in which the digital watermark pattern WM3 is corrected again based on the difference D2 is generated.
4 may be used as a digital watermark pattern for addition to the input signal. By performing such a process, it is possible to embed a digital watermark pattern with enhanced resistance to a plurality of data conversion processes.

[Digital Watermark Detection Processing Apparatus] Next, the configuration of the digital watermark detection processing apparatus will be described with reference to FIG. The digital watermark detection processing device 150 shown in FIG.
For example, a digital video signal DV2 obtained by receiving from a broadcasting station or the like via a medium such as a satellite wave, a terrestrial wave, or a cable.
Or embedded digital watermark information DC is detected from a digital video signal DV2 obtained by reproducing an optical disk or the like.

In the digital watermark detection device 150, the PN
The generation unit 151 generates PN sequence random number data PN, and detects a digital watermark using the random number data PN as a basic pattern. At this time, the PN generation unit 151 sets the digital watermark embedding processing device 1
PN generation unit 121 or PN generation unit 141 at 00
By generating the same random number data PN, it is possible to correctly detect the digital watermark information DC embedded with difficulty in analysis using spread spectrum.

In the digital watermark detection device 150, the inner product calculator 152 receives the digital video signal DV which is sequentially input.
An inner product value with random number data PN is calculated for 2 and an inner product value S is output. The subsequent comparison / determination unit 153 determines the inner product value S
Is compared with an optimally set threshold to determine the presence / absence of digital watermark information DC and the polarity of embedded digital watermark information DC. That is, the following determination is made based on the non-negative threshold value TH.

[0168]

S ≦ −TH: with digital watermark (polarity 0) | S | <TH: without digital watermark S ≧ TH: with digital watermark (polarity 1)

As described above, embedded digital watermark information DC can be detected from an input signal.

For example, when copying a digital video signal DV2 obtained by receiving from a broadcasting station or the like via a medium such as a satellite wave, a terrestrial wave, or a cable, or a digital video signal DV2 obtained by reproducing an optical disk or the like. , So that copying can be restricted based on the digital watermark information DC,
In addition, for sources suspected of being pirated,
It is designed to determine the source of the source.

[Digital Watermark Detection Processing Flow] Next, the processing procedure in the digital watermark detection processing apparatus will be described with reference to FIG.
This will be described with reference to the flow shown in FIG. Each step will be described.

First, in step S31, the digital watermark detection processing device generates PN sequence random number data PN. Subsequently, the digital watermark detection processing device proceeds to step S32
In step S33, an input signal such as a digital video signal DV2 is sequentially read. In step S33, an inner product value of the input signal and the random number data PN is calculated, and an inner product value S is output.

Subsequently, in step S34, the digital watermark detection processing device sets the calculated inner product value S to the set threshold value (T
H), the presence or absence of the digital watermark information DC and the polarity of the embedded digital watermark information DC are determined. That is, with respect to the non-negative threshold value TH, the digital watermark information DC can be detected from the input signal based on the determination of the above [Equation 15]. Subsequently, in step S35, the digital watermark detection processing device outputs the digital watermark information DC thus detected.

Subsequently, the digital watermark detection processing apparatus proceeds to step S36, and determines whether or not processing of the input signal has been completed. If a negative result is obtained here, the processing returns to step S32, and the same processing is sequentially performed for each input data. Is repeated to process the input signal. If an affirmative result is obtained in the end determination of the input signal in step S36, the process is completed.

[System Configuration] The series of processes described in the above embodiments can be executed by hardware, software, or a combination of both. When executing processing by software, a program recording a processing sequence is installed in a memory in a data processing device built in dedicated hardware and executed, or a general-purpose computer capable of executing various processing is used. It is possible to install and run the program. When a series of processes is performed by software, a program constituting the software is installed in, for example, a general-purpose computer or a one-chip microcomputer. FIG.
An example of a system configuration of an apparatus that executes at least one of the series of processes described above, specifically, digital watermark embedding and detection is shown.

The system has a CPU (Central Processing).
Unit 202). CPU (Central processing Uni
t) 202 includes various application programs and OS
(Operating System) is actually executed. ROM (Read
-Only-Memory) 203 stores a program to be executed by the CPU 202 or fixed data as operation parameters. RAM (Random Access Memory) 204
It is used as a storage area and a work area for a program executed in the processing of the CPU 202 and parameters that change as appropriate in the program processing. CPU 20
2. The ROM 203, the RAM 204, and the hard disk 205 are connected by a bus 201, and can mutually transfer data. Further, data transfer with various input / output devices connected to the input / output interface 211 is possible.

A keyboard 212 and a mouse 213 are CPU
The user is operated by the user to input various commands to 202, is operated by the user when inputting command input data, and is input via the keyboard and mouse controller 214.

A drive 209 is a floppy (registered trademark) disk, a CD-ROM (Compact Disc Read Only).
Memory), MO (Magneto optical) disk, DVD (Dig
It is a drive that performs recording and reproduction of a removable recording medium 210 such as an ital Versatile Disc, a magnetic disk, and a semiconductor memory, and reproduces a program or data from each removable recording medium 210 and the removable recording medium 2.
Execute the program or data storage for 10.

The CPU 202 has an input / output interface 2
When a command is input via the keyboard 212, the mouse 213, or the like, via the ROM 10, the ROM (R)
eadOnly Memory) 203 is executed.

In the above-described embodiment, a signal such as an image to be embedded with a digital watermark or a signal to be detected is input to a camera 2071 or other input device connected to the input unit 207, such as a data input device such as a scanner. Alternatively, a floppy disk or CD connected to the drive 209
-ROM (Compact Disc Read Only Memory), MO (Magn
eto optical) Disc, DVD (Digital Versatile Dis)
c), can be input from a removable recording medium 210 such as a magnetic disk or a semiconductor memory. Audio data can be input via the microphone 2072. Furthermore, it is also possible to process data received via the communication unit 208 as data to be embedded with a digital watermark or data to be detected.

The CPU 202 is not limited to the ROM storage program, but may be a program stored in the hard disk 205, a program transferred from a satellite or a network, received by the communication unit 208 and installed in the hard disk 205, or mounted on the drive 209. The program read from the removable recording medium 210 and installed on the hard disk 205 is
It can also be loaded into an AM (Random Access Memory) 204 and executed.

In the system having the configuration shown in FIG. 16, the CPU 202 performs processing according to each of the above-described embodiments, or processing performed according to the above-described block diagrams and flowcharts. Then, the CPU 202 transmits the processing result to an LCD (Liquid Crystal Display) through the input / output interface 211 as necessary, for example.
y), display device 2061 such as CRT, speaker 2062
Is output via the output unit 206. Further, the processing data can be transmitted from the communication unit 208 and further stored in a recording medium such as the hard disk 205.

An execution program for various processes is stored in a hard disk 205 as a recording medium built in the system.
Or in the ROM 203 in advance. Alternatively, the program is a floppy disk, CD-ROM
(Compact Disc Read Only Memory), MO (Magneto opti
cal) Removable recording medium 2 such as disk, DVD (Digital Versatile Disc), magnetic disk, semiconductor memory, etc.
10 can be temporarily or permanently stored (recorded). Such a removable recording medium 210
Can be provided as so-called package software.

The program may be installed in the computer from the removable recording medium 210 as described above, or may be wirelessly transferred from a download site to the computer via an artificial satellite for digital satellite broadcasting, or transmitted from a LAN (Local Area). Network) or the Internet, and the program can be transferred to the computer by wire, and the computer can receive the transferred program by the communication unit 208 and install the program on the built-in hard disk 205.

Here, in this specification, processing steps for writing a program for causing a computer to perform various kinds of processing do not necessarily have to be processed in chronological order in the order described in the flowchart. Alternatively, it also includes processing executed individually (for example, parallel processing or processing by an object).

Further, the program may be processed by one computer, or may be processed in a distributed manner by a plurality of computers. Further, the program may be transferred to a remote computer and executed.

In the above-described embodiment, as the data compression / expansion processing, an example in which an input signal is encoded / decoded by MPEG2 has been mainly described. However, the present invention is not limited to this, and MPEG1, MPEG4, MPEG
The present invention can be widely applied to encoding and decoding signals by various encoding processes such as 7 and the like. In this way, it is possible to realize a general-purpose digital watermark embedding method with enhanced resistance to more encoding processes.

In the data processing for the input signal, there are various processes for a signal in which digital watermark information is embedded, such as encoding, filtering, noise reduction, word length conversion, and the like. It can be applied correspondingly. That is, processing such as encoding, filtering, noise reduction, and word length conversion is performed on an input signal, and correction processing of a digital watermark pattern is performed based on a difference between data before processing and data after processing. It is possible to generate a digital watermark pattern with enhanced resistance to various data processing.

Also, in the above-described embodiment, a case has been described where a digital watermark pattern is generated by spread spectrum of copyright information using random number data, and this digital watermark pattern is added to a digital video signal.
The present invention is not limited to this. Various electronic watermark embedding methods for superimposing a digital watermark on a baseband signal of a digital video signal, and various electronic watermarks for superimposing a digital watermark on a bit stream signal of a digital video signal. It can be widely applied to the watermark embedding method.

Further, in the above-described embodiment, a case has been described in which copyright information is spectrum-spread with PN-sequence random number data. The present invention can be widely applied to the case where the copyright information is modulated in such a manner that it is difficult to analyze the copyright information by the numerical pattern of

In the above-described embodiment, when image analysis is performed in consideration of human visual characteristics, edge information and the like of an image are detected to modulate a digital watermark pattern, and motion information and the like of an image are detected. Although the case where the digital watermark pattern follows the image has been mainly described, the present invention is not limited to this, and when analyzing and processing various information such as luminance information and color information of the image, furthermore, the image analysis Can be widely applied when processing in combination.

Further, in the above-described embodiment, a case has been described in which copyright information is superimposed as a digital watermark. However, the present invention is not limited to this, and various information other than copyright information may be superimposed as necessary. It can be widely applied when transmitting data.

In the above embodiment, the case where a digital video signal is transmitted from a broadcast station or the like via a medium such as a satellite wave, a terrestrial wave, a cable, and the case where the digital video signal is recorded / reproduced on / from an optical disk. As described above, the present invention is not limited to this, and can be widely applied to, for example, transmitting various information via the Internet.

The present invention has been described in detail with reference to the specific embodiments. However, it is obvious that those skilled in the art can modify or substitute the embodiment without departing from the spirit of the present invention. That is, the present invention has been disclosed by way of example, and should not be construed as limiting. In order to determine the gist of the present invention, the claims described at the beginning should be considered.

The various processes described in the specification are
It may be executed not only in chronological order according to the description, but also in parallel or individually according to the processing capability of the device that executes the process or as necessary. Also, in this specification, a system is a logical set configuration of a plurality of devices,
The devices of each configuration are not limited to those in the same housing.

[0196]

As is apparent from the above description, according to the present invention, when an electronic watermark embedding process is performed on an input signal such as a digital video signal, the input signal is encoded and decoded, and the word length is converted. And other data processing, and measure the amount of deterioration due to data processing.Based on the measurement result, determine whether the digital watermark pattern to be superimposed on the input signal is deteriorated by data processing, and correct based on the determination result. Digital watermark pattern is generated and embedded in the input signal, enabling digital watermark embedding with enhanced resistance to data processing such as encoding and word length conversion executed after digital watermark embedding. Become.

Further, according to the configuration of the present invention, the image quality can be improved by reducing or avoiding the embedding level of the digital watermark pattern in an area where the digital watermark pattern is deteriorated by data processing such as encoding and word length conversion. While reducing the amount of surplus embedding that does not contribute to the reliability of detection when undergoing image encoding while affecting the image, furthermore, the surplus embedding amount for this avoidance is encoded, and data processing such as word length conversion is performed. By redistributing to the part that does not deteriorate and controlling the entire embedding strength to a fixed amount, the resistance to data processing such as encoding and word length conversion is strengthened, and the reliability of digital watermark detection can be secured. Become.

Further, according to the structure of the present invention, in the content distribution in the digital network age, the M standard adopted in the moving picture coding standard for digital broadcasting, DVD, etc.
Even after image encoding / decoding using PEG2 or the like, embedded digital watermark information can be detected accurately, and a highly reliable copyright protection system can be constructed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a probability density function of an inner product value for explaining digital watermark detection.

FIG. 2 is a diagram illustrating copyright protection by embedding and detecting a digital watermark.

FIG. 3 is a diagram illustrating a problem of encoding processing in copyright protection by embedding and detecting a digital watermark;

FIG. 4 is a diagram illustrating a word length conversion process.

FIG. 5 is a diagram illustrating a problem of a word length conversion process in copyright protection by embedding and detecting a digital watermark.

FIG. 6 is a diagram illustrating a configuration example of a digital watermark embedding processing apparatus according to the present invention.

FIG. 7 is a diagram illustrating a configuration example of a signal control unit in the digital watermark embedding processing apparatus of the present invention.

FIG. 8 is a diagram illustrating an embedding level adjustment process of the digital watermark embedding processing device of the present invention.

FIG. 9 is a diagram illustrating a configuration example of a signal control unit in the digital watermark embedding processing apparatus of the present invention.

FIG. 10 is a diagram illustrating a configuration example of a signal control unit in the digital watermark embedding processing apparatus of the present invention.

FIG. 11 is a diagram illustrating a configuration example of a digital watermark embedding processing apparatus according to the present invention.

FIG. 12 is a diagram showing a configuration example of a signal control unit in the digital watermark embedding processing apparatus of the present invention.

FIG. 13 is a flowchart showing a processing example of the digital watermark embedding processing device of the present invention.

FIG. 14 is a diagram illustrating a configuration example of a digital watermark detection processing device.

FIG. 15 is a flowchart illustrating a processing example of a digital watermark detection processing device.

FIG. 16 is a diagram illustrating an example of a system configuration that performs at least one of digital watermark embedding and detection processing.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 digital watermark embedding device 2 recording device 3 digital watermark detection device 4 digital watermark rewriting device 5 optical disk 6 recording device 7 optical disk 8 optical disk 11 digital watermark embedding device 12 optical disk 13 recording device 131 digital watermark detection device 14 optical disk 15 image encoding device 16 Optical disk 17 Recording device 171 Digital watermark detection device 18 Optical disk 19 Recording device 191 Image decoding device 192 Digital watermark detection device 21 Digital watermark embedding device 22 Optical disk 23 Recording device 231 Digital watermark detection device 24 Optical disk 25 Word length conversion device 27 Recording device 271 Digital watermark detection device 28 Optical disc 100 Digital watermark embedding processing device 121 PN generation unit 122 Multiplication unit 123 Image analysis unit 124 Signal modulation unit 125 Signal control unit 1 6 Addition unit 127 Compression / expansion unit 128 Difference calculation unit 129 Signal correction unit 130 Addition unit 131 Compression / expansion unit 132 Difference calculation unit 133 Signal correction unit 137 Comparison determination unit 138 Signal correction unit 141 PN generation unit 142 Multiplication unit 143 Image analysis unit 144 Signal modulation section 145 Signal control section 146 Compression / expansion section 147 Difference calculation section 148 Signal correction section 149 Addition section 150 Digital watermark detection processing device 151 PN generation section 152 Inner product calculation section 153 Comparison judgment section 202 CPU 203 ROM 204 RAM 205 Hard disk 206 Output Unit 207 input unit 208 communication unit 209 drive 210 removable recording medium 212 keyboard 213 mouse 214 keyboard mouse controller 2061 display device 2062 speaker 2071 camera 2072 microphone

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H04N 5/92 H04N 7/13 Z 5C078 7/08 7/08 Z 5J104 7/081 5/92 H 7/24 (72 ) Inventor Shunichi Soma 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Takashi Kobashi 6-35-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) ) 5B057 CE08 CG01 CG07 CH08 CH18 5C053 FA13 GA11 GB21 GB37 GB38 5C059 KK01 KK43 MA00 PP01 PP04 RC35 SS11 UA02 UA05 5C063 AB03 AB07 AC01 CA11 CA12 CA23 DA07 DA13 DB09 5C076 AA14 BA06 5C014 AA14BA21

Claims (31)

[Claims] An electronic watermark embedding processor for executing an electronic watermark embedding process, an electronic watermark pattern generating means for generating an electronic watermark pattern based on embedding information, A signal control unit that predicts a deterioration state of the input signal based on the data conversion process, and executes a correction process of the digital watermark pattern generated by the digital watermark pattern generation unit based on the predicted value; A digital watermark embedding processing device, comprising: an adding unit that executes a process of embedding the obtained digital watermark pattern in the input signal. 2. The signal control means includes: a compression / expansion processing means for performing compression / expansion processing on the input signal as the data conversion processing; and processing data after the compression / expansion processing on the input signal by the compression / expansion processing means. A difference calculating means for calculating a difference from the input signal; and a signal correcting means for performing a correction process on the digital watermark pattern generated by the digital watermark pattern generating means based on the difference data output from the difference calculating means. The digital watermark embedding processing apparatus according to claim 1, wherein the digital watermark embedding processing apparatus has a configuration including: 3. The encoding / decoding processing means for executing encoding / decoding processing on the input signal as the data conversion processing, and a code for the input signal by the encoding / decoding processing means. And a difference calculation unit that calculates a difference between the processed data after the decryption processing and the input signal. Based on the difference data output by the difference calculation unit, the digital watermark pattern generated by the digital watermark pattern generation unit is generated. The digital watermark embedding processing apparatus according to claim 1, wherein the digital watermark embedding processing apparatus includes: a signal correction unit configured to perform a correction process. 4. The signal control means according to claim 1, wherein said data conversion processing includes an MP
Coding / decoding processing means for performing coding / decoding processing based on EG2; calculating a difference between the input data and processing data after coding / decoding processing on the input signal by the coding / decoding processing means; And a signal correction unit that executes a correction process of the digital watermark pattern generated by the digital watermark pattern generation unit based on the difference data output by the difference calculation unit. 2. The digital watermark embedding processing device according to claim 1, wherein 5. The word length conversion processing means for executing word length conversion processing on the input signal as the data conversion processing, and the word length conversion processing on the input signal by the word length conversion processing means. A difference calculating means for calculating a difference between the subsequent processing data and the input signal; and a correction processing of the digital watermark pattern generated by the digital watermark pattern generating means, based on the difference data output from the difference calculating means. The digital watermark embedding processing apparatus according to claim 1, wherein the digital watermark embedding processing apparatus has a configuration including: 6. The signal control means according to claim 1, wherein the deterioration state of the input signal based on the data conversion processing on the input signal to be subjected to the digital watermark pattern embedding processing is determined.
2. The apparatus according to claim 1, wherein prediction is performed for each predetermined unit data of the input signal, and correction processing of the digital watermark pattern generated by the digital watermark pattern generating means is executed based on the predicted value. Digital watermark embedding processor. 7. When the input signal to be subjected to the digital watermark pattern embedding processing is an image signal, the signal control means determines whether or not the input signal has been degraded based on the data conversion processing for the image signal. 2. The digital watermark embedding processing apparatus according to claim 1, wherein the digital watermark embedding processing apparatus is configured to perform a prediction process for each digital watermark pattern and execute a correction process of the digital watermark pattern generated by the digital watermark pattern generation unit based on the predicted value. 8. When the input signal to be subjected to the digital watermark pattern embedding process is an image signal, the signal control means determines the degradation state of the input signal based on the data conversion process for the image signal for each pixel of the image signal. 2. The digital watermark embedding processing apparatus according to claim 1, wherein the digital watermark embedding processing apparatus is configured to execute a correction process of the digital watermark pattern generated by the digital watermark pattern generating unit based on the predicted value. 9. The signal control unit predicts a deterioration state of an input signal based on a data conversion process for an input signal to be subjected to a digital watermark pattern embedding process, and based on the predicted value, the digital watermark pattern generation unit For the generated digital watermark pattern, the embedding level of the digital watermark information is reduced for a signal region determined to be largely deteriorated by the data conversion process, and a signal region determined to be small by the data conversion process is reduced. 2. The digital watermark embedding processing apparatus according to claim 1, wherein the digital watermark embedding processing apparatus is configured to execute a correction process for increasing an embedding level of digital watermark information. 10. The signal control means includes: a difference calculation means for calculating a difference between the processing data after the data conversion processing on the input signal and the input signal as an absolute value; an absolute value output by the difference calculation means. 2. The configuration according to claim 1, wherein a deterioration state of the input signal is predicted based on the prediction, and a correction process of the digital watermark pattern generated by the digital watermark pattern generation unit is executed based on the prediction. Digital watermark embedding processor. 11. The signal control means includes: a difference calculation means for calculating a difference between the processing data after the data conversion processing on the input signal and the input signal as an absolute value; an absolute value output from the difference calculation means. However, a signal region that is larger than a predetermined threshold value is determined to have a large deterioration due to the data conversion process, and the level of embedding digital watermark information is reduced for the signal region, and the absolute value is
A signal region having a value smaller than a predetermined threshold value is determined to have a small deterioration due to the data conversion process, and a correction process for increasing an embedding level of digital watermark information is performed on the signal region. Claim 1 characterized by the following:
3. A digital watermark embedding processing device according to claim 1. 12. The signal control means includes: a difference calculation means for calculating a difference between processed data after the data conversion processing on the input signal and the input signal as a value having a positive / negative sign; The apparatus according to claim 1, wherein a deterioration state of the input signal is predicted based on a value to be output, and a correction process of the digital watermark pattern generated by the digital watermark pattern generating unit is executed based on the prediction. 2. The digital watermark embedding processing device according to 1. 13. The signal control means includes: difference calculation means for calculating a difference between processed data after data conversion processing on the input signal and the input signal as a value having a positive / negative sign; If the value to be output has the same sign as the value of the digital watermark pattern generated by the digital watermark pattern generating means, the digital watermark pattern is corrected as it is or the level is increased. When the value to be performed is different from the value of the digital watermark pattern generated by the digital watermark pattern generating means, the value of the digital watermark pattern is set to 0 or the level is reduced. The digital watermark embedding processing device according to claim 1, wherein: 14. The signal control means performs a word length conversion on the input signal, and performs a process of truncating a low-order bit of each value of the input signal. The result data Da (DV1), Data Db obtained by performing a process of discarding the low-order bit of each value of the addition signal obtained by adding the digital watermark pattern generated by the digital watermark pattern generation means
By comparing the difference with (DV1 + WM), if Da (DV1) = Db (DV1 + WM), it is determined that the digital watermark pattern WM is degraded or lost by word length conversion, and Da (DV1) ≠ Db (DV1 + WM). If there is, it is determined that the digital watermark pattern WM does not deteriorate or disappear due to the word length conversion, and the level of the digital watermark pattern in the area determined to deteriorate or disappear due to the word length conversion is reduced or the value is set to 0,
2. The digital watermark embedding processing apparatus according to claim 1, wherein the digital watermark embedding processing apparatus is configured to execute a correction for increasing a level of a digital watermark pattern in a region determined not to be deteriorated or lost by the word length conversion. 15. The digital watermark pattern generating means includes signal modulation means for modulating a digital watermark pattern initially generated based on the analysis of the input signal, and the signal control means outputs the signal from the signal modulation means. 2. The digital watermark embedding processing apparatus according to claim 1, further comprising a configuration for executing a digital watermark pattern correction process. 16. A digital watermark embedding method for executing a digital watermark embedding process, comprising the steps of: generating a digital watermark pattern based on embedding information; A signal control step of predicting a deterioration state of the input signal based on the data conversion processing, and performing a correction process of the digital watermark pattern generated in the digital watermark pattern generation step based on the predicted value; An embedding step of performing a process of embedding the obtained digital watermark pattern in the input signal. 17. The signal control step includes: a compression / expansion processing step of performing a compression / expansion processing on the input signal as the data conversion processing; and a compression / expansion processing on the input signal generated in the compression / expansion processing step. A difference calculation step of calculating a difference between the processing data and the input signal; and a signal for performing a correction process of the digital watermark pattern generated in the digital watermark pattern generation step based on the difference data output in the difference calculation step. 17. The digital watermark embedding processing method according to claim 16, comprising: a correcting step. 18. The signal control step, wherein, as the data conversion processing, an encoding / decoding processing step of executing encoding / decoding processing on the input signal; and the input signal generated in the encoding / decoding processing step A difference calculation step of calculating a difference between the input data and the processed data after the encoding / decoding process, and a digital watermark generated in the digital watermark pattern generation step based on the difference data output in the difference calculation step. 17. The digital watermark embedding method according to claim 16, further comprising: a signal correcting step of performing a pattern correcting process. 19. The signal control step, wherein, as the data conversion process, an MP
An encoding / decoding process step of executing an encoding / decoding process based on EG2; a difference between the input signal and the processed data after the encoding / decoding process for the input signal generated in the encoding / decoding process step. And a signal correction step of performing a correction process of the digital watermark pattern generated in the digital watermark pattern generation step based on the difference data output in the differential calculation step. The digital watermark embedding processing method according to claim 16. 20. The signal control step, wherein, as the data conversion processing, a word length conversion processing step for performing a word length conversion processing on the input signal; and a word length for the input signal generated in the word length conversion processing step. A difference calculating step of calculating a difference between the processing data after the conversion processing and the input signal; and a correction processing of the digital watermark pattern generated in the digital watermark pattern generating step based on the difference data output in the difference calculating step 17. The digital watermark embedding processing method according to claim 16, further comprising: a signal correcting step of performing the following. 21. The signal control step according to claim 16, further comprising the steps of:
17. The method according to claim 16, further comprising the step of: performing a prediction for each predetermined unit data of the input signal, and executing a correction process of the digital watermark pattern generated in the digital watermark pattern generating step based on the predicted value. Digital watermark embedding processing method. 22. The signal control step, wherein, when the input signal to be subjected to the digital watermark pattern embedding processing is an image signal, the deterioration state of the input signal based on the data conversion processing on the image signal is determined by a predetermined area of the image signal. 17. The digital watermark embedding processing method according to claim 16, further comprising the step of: performing a prediction process for each digital watermark pattern and executing a correction process of the digital watermark pattern generated in the digital watermark pattern generation step based on the predicted value. 23. The signal control step, wherein, when an input signal to be subjected to a digital watermark pattern embedding process is an image signal, a deterioration state of the input signal based on a data conversion process on the image signal is determined for each pixel of the image signal. 17. The digital watermark embedding processing method according to claim 16, further comprising: performing a correction process of the digital watermark pattern generated in the digital watermark pattern generating step based on the predicted value. 24. The signal control step predicts a deterioration state of an input signal based on a data conversion process for an input signal to be subjected to a digital watermark pattern embedding process, and based on the predicted value, the digital watermark pattern generating step For the generated digital watermark pattern, the embedding level of the digital watermark information is reduced for a signal region determined to be largely deteriorated by the data conversion process, and a signal region determined to be small by the data conversion process is reduced. 17. The digital watermark embedding processing method according to claim 16, further comprising the step of executing a correction process for increasing the level of embedding digital watermark information. 25. The signal control step includes: a difference calculation step of calculating a difference between the processed data after the data conversion processing on the input signal and the input signal as an absolute value; and an absolute value output in the difference calculation step. Based on the prediction of the degradation state of the input signal, based on the prediction,
17. The digital watermark embedding method according to claim 16, further comprising: performing a correction process on the digital watermark pattern generated in the digital watermark pattern generating step. 26. The signal control step, comprising: a difference calculation step of calculating, as an absolute value, a difference between processed data after data conversion processing on the input signal and the input signal; and an absolute value output in the difference calculation step. However, it is determined that a signal region having a value larger than a predetermined threshold value is greatly deteriorated by the data conversion process, and the embedding level of digital watermark information is reduced for the signal region. A signal region that is smaller than the determined threshold value determines that deterioration due to the data conversion process is small,
17. The digital watermark embedding method according to claim 16, further comprising: performing a correction process for increasing a level of embedding digital watermark information in the signal area. 27. The signal control step, comprising: calculating a difference between processed data after data conversion processing on the input signal and the input signal as a value having a positive / negative sign; Based on the output value,
17. The method according to claim 16, further comprising: predicting a deterioration state of the input signal, and executing a correction process of the digital watermark pattern generated in the digital watermark pattern generating step based on the prediction. Watermark embedding processing method. 28. The signal control step, wherein a difference between the processed data after the data conversion processing on the input signal and the input signal is calculated as a value having a positive or negative sign. If the value to be output has the same sign as the value of the digital watermark pattern generated in the digital watermark pattern generating step, the digital watermark pattern is corrected as it is or the level is increased. If the value to be performed is different from the value of the digital watermark pattern generated in the digital watermark pattern generating step, the value of the digital watermark pattern is set to 0, or a correction is performed to reduce the level. 17. The digital watermark embedding processing method according to claim 16, comprising: 29. The signal control step, wherein the result data Da (DV1) obtained by executing a word length conversion on the input signal and performing a process of discarding low-order bits of each value of the input signal, and the input signal, The difference from the result data Db (DV1 + WM) obtained by executing the process of discarding the low-order bit of each value of the added signal obtained by adding the digital watermark pattern generated in the digital watermark pattern generating step is compared, and Da (DV1) = Db (DV1 + WM) If, it is determined that the digital watermark pattern WM is degraded or lost by the word length conversion. If Da (DV1) ≠ Db (DV1 + WM), it is determined that the digital watermark pattern WM is not degraded or lost by the word length conversion. And lower the level of the digital watermark pattern in the area determined to be degraded or lost by word length conversion. Or set the value to 0,
17. The digital watermark embedding processing method according to claim 16, further comprising the step of performing a correction for increasing the level of a digital watermark pattern in an area determined not to be deteriorated or lost by the word length conversion. 30. The digital watermark pattern generating step includes a signal modulating step of modulating a digital watermark pattern initially generated based on the analysis of the input signal, and the signal controlling step outputs in the signal modulating step. 17. The digital watermark embedding method according to claim 16, further comprising the step of executing a digital watermark pattern correction process. 31. A program for executing a digital watermark pattern embedding process on a computer system, comprising: a digital watermark pattern generating step of generating a digital watermark pattern based on embedded information; A signal control step of predicting a deterioration state of an input signal based on a data conversion process for the signal, and performing a correction process of the digital watermark pattern generated in the digital watermark pattern generation step based on the predicted value; An addition step of executing a process of embedding the digital watermark pattern corrected in the above in the input signal.