JP2003333549A - Electronic watermark embedding apparatus, electronic watermark embedding method, and recording medium with electronic watermark - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic watermark embedding apparatus, an electronic watermark embedding method, and a recording medium with electronic watermark capable of surely detecting a watermark in the case of applying noise reduction and data compression to contents information. <P>SOLUTION: The electronic watermark embedding apparatus for embedding an electronic watermark comprising signals produced based on a prescribed rule to contents comprising digital information includes: a noise reduction section 407 for applying noise reduction to the contents information; a strength setting section 404 and a strength revision section 405 for varying the strength of the electronic watermark embedded to the contents; and a control section 414 for controlling the strength revision section 405 in a manner of varying the strength of the electronic watermark in interlocking with the strength of the noise reduction by the noise reduction section 407. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital watermark embedding device, a digital watermark embedding method, and a recording medium having a digital watermark, in which a digital watermark for restricting copying is embedded in content consisting of digital information.

[0002]

2. Description of the Related Art With the realization of digital television broadcasting, distribution of video by digital signals is becoming common. Also,
Video recorders that record video as digital data on optical disks, magnetic tapes, etc. are also becoming popular. If the video can be recorded as digital data, the video can be duplicated without deterioration. Therefore, it is necessary to restrict copying of the video from the viewpoint of copyright.

For example, the watermark (digital watermark) technology disclosed in Japanese Patent Laid-Open No. 2000-173175 is one of the technologies for restricting the copying of images, and is a technique for embedding information on the restriction of copying of digital images. Hereinafter, the information regarding the copy restriction to be embedded in the digital video will be referred to as “watermark”. The watermark is embedded so as to be hidden in the image. Therefore, even if the watermark is embedded in the video, the quality of the video is hardly degraded. Further, it is extremely difficult to remove the watermark from the image because the person who receives the image in which the watermark is embedded may not recognize that the watermark is present in the image.

Japanese Patent Laid-Open No. 2000-173175 discloses a system using a watermark indicating that copying is prohibited and a watermark indicating that copying is permitted for one generation. According to such a system, the number of times of copying can be managed, so that the receiver of the television broadcast can watch the delivered video without being restricted by the broadcast time without causing a copyright problem. it can.

In this system, when a digital image is input to the video recorder, the video recorder determines whether or not a watermark is present in the image.
If a watermark exists and the watermark indicates that copying is prohibited, the video recorder does not record the image. If the watermark does not exist, or if the watermark exists but the watermark indicates permission for one-generation copying, the video recorder determines that the image is allowed to be copied once. Judgment is made and the image is recorded on, for example, an optical disc.
At this time, if the watermark indicates that one-generation copying is permitted, the video recorder embeds a watermark indicating that copying is prohibited and records the image.

[0006]

[Problems to be Solved by the Invention] Video tape and DVD
There is a case where a noise reduction process for reducing a noise component of a video is performed when a package medium such as the above is manufactured or a video is distributed from a broadcasting station. In addition, the compression bit rate when performing compressed recording may be changed depending on the work, or the compression bit rate may be switched within one work. However, when the watermark is embedded in the video content, the watermark is affected by the strength of noise reduction processing when recording the video content and the compression bit rate. Since the degree of deterioration of the watermark changes in conjunction with the strength of these processes, for example, when the strength of noise reduction processing is increased or when the compression bit rate is decreased (compression rate is increased). The degree of deterioration may increase, and it may be difficult to read the watermark during reproduction.

Further, when the strength of noise reduction processing is increased or the compression bit rate is decreased,
Usually, the image of that part tends to be flat. However, in a flat image, the watermark is likely to be conspicuous, so the strength is weakened and the watermark is embedded. Therefore, if the state of high noise reduction processing or the state of low compression bit rate continues, as a result, the state of low watermark strength will continue, which may make it difficult to detect the watermark. There is.

According to the present invention, a digital watermark embedding device, a digital watermark embedding method, and a recording medium having a digital watermark, which can reliably detect a watermark when noise reduction processing or data compression processing is performed on content information. The purpose is to provide.

[0009]

A digital watermark embedding device of the present invention is a digital watermark embedding device for embedding a digital watermark consisting of a signal generated based on a predetermined rule in a content consisting of digital information. Noise reduction means for applying noise reduction processing to information (407
Etc.), changing means (404, 405, etc.) for changing the strength of the digital watermark embedded in the content, and changing the strength of the digital watermark in conjunction with the strength of noise reduction processing by the noise reducing means (407, etc.). , Fluctuation means (40
4, 405 and the like), and a control unit (414 and the like) for controlling.

According to this digital watermark embedding apparatus, since the strength of the digital watermark to be embedded in the content is changed in association with the strength of the noise reduction processing by the noise reduction means, even if the noise reduction processing is performed, the watermark can be applied. The watermark can be embedded in a state where the watermark can be reliably detected.

The digital watermark embedding device of the present invention is a digital watermark embedding device for embedding a digital watermark consisting of a signal generated based on a predetermined rule into a content consisting of digital information, and compresses and encodes information of the content. Compression encoding means (408 etc.) and changing means (40) for changing the strength of the digital watermark embedded in the content.
4, 405, etc.) and the control means for controlling the varying means (404, 405, etc.) so as to change the strength of the digital watermark in conjunction with the compression strength of the compression coding processing by the compression coding means (408, etc.). (414 etc.) are provided.

According to this digital watermark embedding apparatus, since the strength of the digital watermark to be embedded in the content is changed in association with the compression strength of the compression coding processing by the compression coding means, the compression coding processing may be performed. Also, the watermark can be embedded in a state in which the watermark can be reliably detected.

The digital watermark embedding method of the present invention is a digital watermark embedding method for embedding a digital watermark composed of a signal generated based on a predetermined rule in a content composed of digital information, wherein noise reduction processing is performed on the content information. A noise reduction procedure to be performed and a variation procedure for varying the strength of the digital watermark embedded in the content are provided, and the variation procedure changes the strength of the digital watermark in conjunction with the strength of noise reduction processing by the noise reduction procedure. And

According to this digital watermark embedding method, the strength of the digital watermark to be embedded in the content is changed in association with the strength of the noise reduction processing by the noise reduction procedure. Therefore, even when the noise reduction processing is performed, the watermark is applied. The watermark can be embedded in a state where the watermark can be reliably detected.

The digital watermark embedding method of the present invention is a digital watermark embedding method for embedding a digital watermark composed of a signal generated based on a predetermined rule into a content composed of digital information, and compresses and encodes the content information. A compression / encoding procedure and a varying procedure for varying the strength of the digital watermark embedded in the content are provided, and in the varying procedure, the strength of the digital watermark is changed in association with the compression strength of the compression coding process by the compression coding procedure. It is characterized by

According to this digital watermark embedding method, since the strength of the digital watermark to be embedded in the content is changed in association with the compression strength of the compression coding processing by the compression coding procedure, the compression coding processing may be performed. Also, the watermark can be embedded in a state in which the watermark can be reliably detected.

A recording medium having a digital watermark of the present invention is
A recording medium having a digital watermark, in which a video in which a digital watermark made of a signal generated based on a predetermined rule is embedded in the content made of digital information is recorded, and the content information is subjected to noise reduction processing. Is recorded, and the strength of the digital watermark changes in association with the strength of noise reduction processing.

According to the recording medium having the digital watermark embedding, the strength of the digital watermark to be embedded in the content changes in association with the strength of the noise reduction processing. Therefore, even when the noise reduction processing is performed, the watermark is embedded. The watermark can be detected reliably.

A recording medium having a digital watermark of the present invention is
A recording medium having a digital watermark in which a video in which a digital watermark made of a signal generated based on a predetermined rule is embedded in the content made of digital information is recorded, and the content information is compressed and encoded. It is characterized in that the strength of the digital watermark is changed and recorded in association with the compression strength of the data compression processing.

According to the recording medium having the digital watermark, since the strength of the digital watermark embedded in the content changes in association with the strength of the compression coding process, even when the compression coding process is performed, The embedded watermark can be reliably detected.

In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are added in parentheses, but the present invention is not limited to the illustrated forms.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a digital watermark embedding device according to the present invention will be described below in detail with reference to the drawings. In addition, in the present embodiment, the video content is exemplified as the content including the digital information,
It can be applied to contents that consist of all digital information such as music contents.

First Embodiment The first embodiment of the digital watermark embedding device according to the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing a digital watermark embedding device 401 of the first embodiment. The digital watermark embedding device 401 embeds a watermark (digital watermark) in a baseband video signal.

As shown in FIG. 1, the digital watermark embedding device 401 is a PN sequence generation unit 403 which generates a PN (Pseudorandom Noise) sequence forming a watermark (digital watermark) used as information relating to copy restriction of video content. And a strength setting unit 4 that amplifies the PN series output from the PN series generation unit 403 and sets the strength thereof.
04, and a strength changing unit 405 that changes the strength of the PN sequence.
And an adding unit 406 for adding the video signal and the PN sequence,
Noise reduction unit 40 for reducing noise of video signal
7 and MPE for compressing and encoding video content data
A G encoder 408, a storage unit 410 having a RAM and a ROM, a display unit 411 for presenting predetermined information to the operator, and an operation unit 4 for accepting the operation of the operator.
12 and a control unit 414 that controls the above units.

The digital watermark embedding device 401 can be used, for example, as a part of broadcasting equipment of a broadcasting station. In this case, the video can be distributed by amplifying the MPEG stream output from the MPEG encoder 408 by the video signal output device and transmitting it through the antenna.

Further, the digital watermark embedding device 401 is
For example, it can be used as a part of a recording device used in a movie company or the like. In this case, embed the watermark in the content without the watermark,
Content can be recorded on a recording medium such as an optical disk or a video tape.

Next, the watermark formed by the PN sequence generated by the PN sequence generation unit 403 will be described with reference to FIGS.

The digital image contains information indicating the brightness of each image forming the digital image. The information indicating the brightness is, for example, a numerical value of about 4 to 8 bits, and corresponds to each pixel forming the image. That is, the numerical value indicating the brightness is individually set for each pixel (hereinafter, the numerical value indicating the brightness of the pixel is referred to as a “brightness value”). This will be specifically described with reference to FIG. 2. The image P1 in FIG. 2 is one of the images forming a digital video, and a, b, c, d, ... In the image P1 are pixels. The luminance value set to is shown.

The watermark is composed of a signal generated based on a predetermined rule, for example, a PN series in the present embodiment, and each code of the PN series is added to the luminance value of the pixel in the image. Embedded in. For example, "0011 ..." In FIG. 2 is a PN sequence forming a watermark. This PN sequence is image P1
By adding to the brightness values a, b, c, d, ...
As shown in FIG. 3, the brightness values are a, b, c + 1, d + 1,
… Will be. In this way, the watermark is embedded in each image forming the digital image.

The PN sequence forming the watermark is a sequence of pseudo-random codes such as M sequence, and is generated by giving an initial value to a polynomial (generation formula) for generating the PN sequence. In the present embodiment, a polynomial (generation formula) for generating a PN sequence is embodied as a PN sequence generation circuit 1 as shown in FIG. 4, for example. The PN sequence generation circuit 1 includes a shift register 1A
˜1D and adder 1E, provided in PN sequence generation section 403. The PN sequence actually used has a larger number of shift registers so that the sequence period becomes longer.

Further, in this embodiment, two types of PN sequences different from each other are generated, one of them is used as a watermark indicating permission of one-generation copying, and the other is used as a watermark indicating prohibition of copying. PN series is
The array of random codes is changed by changing one or both of the polynomial and the initial value.
Therefore, different PN sequences can be generated by changing one or both of the polynomial and the initial value.

For example, the PN series used as a watermark indicating the permission of the first generation copy is generated by the PN series generation circuit 1 shown in FIG. On the other hand, a PN sequence used as a watermark indicating that copying is prohibited is generated by the PN sequence generation circuit 2 shown in FIG. PN shown in FIG.
The sequence generation circuit 2 embodies a polynomial (generation formula) different from the polynomial (generation formula) corresponding to the PN sequence generation circuit 1, and has shift registers 2A to 2D and an adder 2E.
It is composed by. The PN sequence generation circuit 2 also has P
It is provided in the N-series generation unit 403.

A polynomial corresponding to the PN sequence generation circuit 1 and P
It is clear that the polynomials corresponding to the N-series generation circuit 2 are different because the connection of the shift register and the adder is different between the PN series generation circuit 1 and the PN series generation circuit 2. In this way, by using two PN sequence generation circuits having different connections or configurations (that is, two polynomials having different structures), a watermark indicating one-generation copy permission and a watermark indicating copy prohibition are generated respectively. You can

It is also possible to generate the watermark indicating the first generation copy permission and the watermark indicating the copy prohibition, respectively, using only the PN sequence generation circuit 1 shown in FIG. In this case, two types of initial values to be given to the PN sequence generation circuit 1 are prepared. By giving one of these two types of initial values to the PN sequence generation circuit 1, a PN sequence forming a watermark indicating permission for one-generation copying is generated, and the other initial value is generated with the same PN sequence. By applying this to the circuit 1, it is possible to generate a PN sequence forming a watermark indicating that copying is prohibited. For example, P that constitutes the watermark indicating the permission of the first-generation copying
When generating the N series, the initial value "0011" is input to the shift registers 1A to 1D. On the other hand, when generating a PN sequence forming a watermark indicating that copying is prohibited, the shift register 1A to 1D has an initial value "01".
Enter "01".

Next, the operation of the strength setting section 404 will be described.

As shown in FIG. 1, the intensity setting unit 404 outputs the video signal and the P output from the PN sequence generation unit 403.
N series and are input. Then, the strength setting unit 404
Based on the inputted video signal, the PN sequence generation unit 403
Set the PN sequence from to the appropriate strength. To be more specific, the intensity setting unit 404 detects whether the brightness values set in the pixels forming one image are largely changed or slightly changed. When the brightness value is greatly changed, the image has a complicated pattern, for example, so that the watermark is not noticeable even if the watermark is embedded. Therefore, when the brightness value is largely changed, the intensity setting unit 404 causes the PN
The PN sequence output from the sequence generation unit 403, that is, the strength of the watermark is set to be high. For example, when the PN sequence is “0101 ...”, the strength setting unit 404
Will call this "0202 ..." or "0303 ..."
Set to. Then, the strength setting unit 404 sets the set P
The N series is output to the intensity changing unit 405.

On the other hand, when the brightness value set for each pixel constituting one image changes slightly, the image is, for example, a flat image, so that the watermark is easily noticeable. Therefore, when the brightness value is changing slightly, the intensity setting unit 404 causes the PN sequence generation unit 40 to
The PN sequence output from No. 3 is directly used as the intensity changing unit 405.
Output to.

Next, the operation of the intensity changing unit 405 will be described.

The PN sequence output from the intensity setting unit 404 has its intensity changed by the intensity changing unit 405 and is output to the adding unit 406. The adding unit 406 superimposes the PN sequence from the intensity changing unit 405 on the video signal and embeds the watermark in the video.

The intensity changing unit 405 determines the intensity of noise reduction processing in the noise reduction unit 407 and MPEG.
Depending on the bit rate of compression encoding in the encoder 408 or the compression rate of compression encoding, the strength setting unit 404.
The strength of the PN sequence output from is changed. As a result, the intensity changing unit 405 causes the noise reduction unit 407.
This prevents the watermark from becoming unreadable due to the noise reduction processing in step 1 and the compression encoding processing in the MPEG encoder 408.

That is, when the content is produced based on an old source, the noise component included in the source is removed, and thus the strength of the noise reduction process may be increased. In addition, the bit rate for the compression encoding process may be set low based on the nature of the image, the required recording capacity, and the like. In these cases, the watermark embedded in the content may be deteriorated by noise reduction processing or compression encoding processing, and it may be difficult to detect the watermark during reproduction.

Therefore, in the present invention, the strength of the noise reduction processing and the strength of the watermark, and the bit rate of the compression coding and the strength of the watermark are linked. As shown in FIG. 1, the control unit 414 controls the noise reduction unit 407 and the MPEG encoder 408, and controls the intensity of noise reduction processing in the noise reduction unit 407 and the bit rate of compression encoding in the MPEG encoder 408. There is. The control signal for controlling the strength of the noise reduction processing and the bit rate of the compression encoding is also given to the strength changing unit 405,
The amplification degree of the intensity changing unit 405 changes based on this control signal.

As a result, the intensity changing unit 405 is controlled by the control unit 414 to determine the PN sequence output from the intensity setting unit 404, that is, the watermark intensity, as the intensity of noise reduction processing and the bit rate of compression encoding. The strength of the watermark is increased when the strength of the noise reduction processing is increased, and the strength of the watermark is increased when the bit rate of the compression coding is decreased. In this way, the digital watermark embedding apparatus 401 can embed the watermark with such strength as to cancel the effects of the noise reduction processing in the noise reduction unit 407 and the compression encoding in the MPEG encoder 408, and thus the video in which the watermark is embedded. The watermark is reliably detected when the content is played.

Further, when the strength of the noise reduction processing is increased or when the bit rate of the compression coding is decreased, the image quality is often deteriorated in general. Therefore, in the part where the noise reduction processing is increased in strength or in the part where the compression coding bit rate is decreased, the image quality is often deteriorated originally by these processings. Even if you raise
The deterioration of the image quality due to the watermark is not noticeable.

Note that the strength changing unit 405 increases the strength of the watermark at regular intervals (constant time intervals) during the period when the noise reduction process is high or the compression coding bit rate is low. For a short period, for example, only a few frames (1 to 3 frames) may be used. That is, the intensity changing unit 405 is controlled by the control unit 414,
The strength of the watermark that reflects the strength of the noise reduction processing and the bit rate of the compression coding is intermittently increased by several frames. In this way, the watermark whose intensity is increased intermittently or in a pulse shape is more likely to be displayed in the image than the watermark whose intensity is increased over the period of high intensity of noise reduction processing and low bit rate of compression encoding. Although it is inconspicuous on the screen, it is definitely detected.

Further, the period during which the intensity changing unit 405 increases the intensity of the watermark is a random interval or an indefinite interval according to some law during the period when the noise reduction process is high and the compression coding bit rate is low. Only a few frames may be (random or indefinite time interval). This is because the watermark becomes more inconspicuous in the image when it is increased at random intervals or indefinite intervals, compared to the case where the watermark is increased at regular intervals.

Further, the period during which the intensity changing unit 405 increases the intensity of the watermark is only a few frames according to the change of the image during the period when the intensity of the noise reduction process is high and the bit rate of the compression encoding is low. But it's okay.
For example, when there is a large change in the image over time, such as a scene change, when there is a large change in the image within a frame, such as an image with many strong edges, or when the motion vector is large. The watermark may be increased by a few frames at intense timing.

Second Embodiment With reference to FIG. 6, a second embodiment of the digital watermark embedding device of the present invention will be described below. In FIG. 6, the first
The same reference numerals are given to the elements corresponding to the configurations of the embodiments, and the description thereof will be omitted.

FIG. 6 is a block diagram showing a digital watermark embedding device 401A according to the second embodiment. This digital watermark embedding device 401A uses the MPEG content for the video content.
The watermark is embedded in the encoded MPEG stream, and can be used, for example, as a part of a recording device that records a video signal transmitted from a broadcasting station or the like on a recording medium.

As shown in FIG. 6, in the digital watermark embedding apparatus 401A of the second embodiment, the noise reduction unit 407 performs noise reduction processing on the video signal,
Further, the MPEG encoder 408 executes compression encoding processing, and inputs the MPEG stream obtained by compression encoding to the intensity setting unit 404A and the addition unit 406A. Therefore, the strength setting unit 404A sets the strength of the PN sequence based on this MPEG stream. In addition, the addition unit 406A adds a PN sequence to this MPEG stream.

The intensity changing unit 405A is controlled by the control unit 414 to change the intensity of the watermark output from the intensity setting unit 404A in association with the intensity of noise reduction processing and the bit rate of compression encoding, When the strength of the noise reduction processing is high, the strength of the watermark is increased, and when the bit rate of the compression coding is low, the strength of the watermark is increased. As the operation of the strength changing unit 405A, the same operation as that of the strength changing unit 405 in the first embodiment can be adopted.

As described above, the digital watermark embedding device 4
01A is a noise reduction unit 40 for the video signal.
7 noise reduction processing and MPEG encoder 40
8, the PN series, that is, the watermark is superimposed on the generated MPEG stream. Normally, when the intensity of the noise reduction processing by the noise reduction unit 407 is high or when the bit rate of the compression encoding by the MPEG encoder 408 is low, the image subjected to the noise reduction processing or the compression encoding is flat. Tend to be. For this reason, if the intensity of the noise reduction processing is high or the bit rate of the compression encoding by the MPEG encoder 408 continues to be low, the intensity of the watermark set in the intensity setting unit 404A is kept low for a long time. May be done. However, as described above, the strength changing unit 405A
Changes the strength of the watermark according to the strength of the noise reduction processing by the noise reduction unit 407 or the bit rate of the compression encoding by the MPEG encoder 408, so that the strength of the noise reduction processing is high or the MPEG encoder 408 Even if the bit rate of the compression encoding by the method continues, the state where the watermark strength is low is not maintained.
Therefore, the watermark is reliably detected when the video content in which the watermark is embedded is reproduced.

The digital watermark embedding device 401A
Since the watermark is embedded after the noise reduction processing or the compression encoding processing that eventually deteriorates the watermark, there is no risk of the watermark being deteriorated by the noise reduction processing or the compression encoding processing. Therefore, the digital watermark embedding device 401A has an advantage of being able to more appropriately manage the strength and state of the watermark of the video signal output as the MPEG stream.

-Third Embodiment- With reference to FIG. 7, a third embodiment of the digital watermark embedding device of the present invention will be described below. In FIG. 7, the first
The same reference numerals are given to the elements corresponding to the configurations of the embodiments, and the description thereof will be omitted.

FIG. 7 is a block diagram showing a digital watermark embedding device 401B of the third embodiment. The digital watermark embedding device 401B is for re-embedding (remarking) a watermark in a baseband video signal in which a watermark has already been embedded. It can be used as a part of equipment or a recording device of a movie company.

As shown in FIG. 7, the digital watermark embedding device 401B includes a watermark detecting section 415 for detecting a watermark from an input video signal.

The watermark detection unit 415, before recording the received video signal on a recording medium such as an optical disk,
Whether the watermark is embedded in the video signal,
Further, it detects whether the watermark embedded in the video signal indicates one-generation copy permission or copy prohibition, and outputs the detection result to the control unit 414.

When the watermark detection unit 415 detects a watermark indicating permission for the first-generation copy, PN
The sequence generation unit 403 generates a PN sequence corresponding to prohibition of copying. The intensity of the PN sequence is set by the intensity setting unit 404 as in the first embodiment, and the intensity is changed by the intensity changing unit 405. Strength changing unit 405
The PN sequence output from is added to the video signal in the addition unit 406.

The intensity changing unit 405 is controlled by the control unit 414 to change the intensity of the watermark output from the intensity setting unit 404 in association with the intensity of noise reduction processing and the bit rate of compression to reduce noise. The strength of the watermark increases as the strength of the processing increases, and the strength of the watermark increases as the bit rate of compression decreases. As the operation of the strength changing unit 405, the same operation as that of the strength changing unit 405 in the first embodiment can be adopted. The video signal in which the watermark is embedded is subjected to noise reduction by the noise reduction unit 407 and MPEG encoding by the MPEG encoder 408, and is output as an MPEG stream.

Thus, the digital watermark embedding device 40
When 1B detects that the watermark indicating the permission of the 1st generation duplication is embedded, the 1B duplication is performed with such strength as to cancel the influence of the noise reduction processing in the noise reduction unit 407 and the compression encoding in the MPEG encoder 408. A watermark indicating prohibition can be remarked on the video content. Therefore, the remarked watermark can be reliably detected.

When the watermark detecting unit 415 does not detect the watermark indicating the first generation duplication permission and the watermark indicating duplication prohibition, since the content is permitted for duplication, the adding unit 406 remarks the watermark. It is output as an MPEG stream without being processed.

When the watermark detection section 415 detects a watermark indicating that copying is prohibited, the control section 414 executes control to prohibit recording.

Fourth Embodiment Hereinafter, a fourth embodiment of the digital watermark embedding device of the present invention will be described with reference to FIG. In FIG. 8, the first
The same reference numerals are given to the elements corresponding to the configurations of the embodiments, and the description thereof will be omitted.

FIG. 8 is a block diagram showing a digital watermark embedding device 401C of the fourth embodiment. This digital watermark embedding device 401C is for re-embedding (remarking) a watermark in an MPEG stream in which a watermark has already been embedded, and like the digital watermark embedding device 401A, a video signal transmitted from a broadcast station It can be used as a part of a recording device for recording on a recording medium.

As shown in FIG. 8, the digital watermark embedding apparatus 401C performs noise reduction processing by the noise reduction unit 407 and MP processing on an input video signal.
A watermark detection unit 415A that detects a watermark from the MPEG stream generated by performing the compression coding processing by the EG encoder 408 is provided.

Before recording the received MPEG stream on a recording medium such as an optical disc, the watermark detection unit 415A determines whether or not the watermark is embedded in the MPEG stream, and the watermark embedded in the MPEG stream. Indicates whether one-generation copy permission or copy prohibition is present, and outputs the detection result to the control unit 414.

If the watermark detection unit 415A detects a watermark indicating permission for the first-generation copying, P
The N sequence generation unit 403 generates a PN sequence corresponding to copy inhibition. The strength of this PN sequence is set by the strength setting section 404A, as in the strength setting section 404 in the first embodiment, and is further changed by the strength changing section 405A. PN output from the intensity changing unit 405A
The series is added to the MPEG stream in the adding unit 406A.

The intensity changing unit 405A is controlled by the control unit 414 to change the intensity of the watermark output from the intensity setting unit 404A in association with the intensity of noise reduction processing and the bit rate of compression to reduce noise. The strength of the watermark increases as the strength of the processing increases, and the strength of the watermark increases as the bit rate of compression decreases. As the operation of the strength changing unit 405A, the same operation as that of the strength changing unit 405 in the first embodiment can be adopted.

As described above, since the strength changing unit 405A changes the strength of the watermark according to the strength of the noise reduction processing by the noise reduction unit 407 or the bit rate of the compression encoding by the MPEG encoder 408, the noise reduction is performed. High processing intensity or M
Even if the state in which the bit rate of the compression encoding by the PEG encoder 408 is low continues, the state in which the watermark strength is low is not maintained. Therefore, the watermark is reliably detected when the video content in which the watermark is embedded is reproduced.

The digital watermark embedding device 401C
Since the watermark is remarked after the noise reduction processing and the compression encoding processing that eventually deteriorate the watermark, the watermark is not deteriorated by the noise reduction processing and the compression encoding processing.
Therefore, the digital watermark embedding device 401C is
There is an advantage that the strength and state of the watermark of the video signal output as a stream can be managed more appropriately.

When the watermark detecting unit 415A does not detect the watermark indicating the first-generation duplication permission and the watermark indicating the duplication prohibition, the addition unit 406A remarks the watermark because the content is permitted for duplication. MP as it is without being
It is output as an EG stream.

When the watermark detection section 415A detects a watermark indicating that copying is prohibited, the control section 414 executes control for prohibiting recording.

Here, in the digital watermark embedding device 401B shown in FIG. 7, the watermark detection section 415 and the addition section 406 are located upstream of the noise reduction section 407. That is, the electronic watermark embedding device 401B detects and remarks the watermark of the video signal before noise reduction. Also, in the digital watermark embedding device 401C shown in FIG. 8, the watermark detection unit 415A and the addition unit 406A are
It is located downstream of the EG encoder 408. That is, the digital watermark embedding device 401C detects and remarks the watermark of the MPEG stream generated by performing noise reduction and MPEG encoding on the video signal.

As described above, in the digital watermark embedding devices 401B and 401C shown in FIGS. 7 and 8, the watermark detection and the watermark remarking are the same when the positions of the noise reduction unit 407 and the MPEG encoder 408 are used as references. Running in position.

However, the digital watermark embedding device according to the present invention is not limited to such a configuration. For example, as shown in FIG. 9, the position on the upstream side of the noise reduction unit 407 is A, and the noise reduction unit 40 is
7 and the position between the MPEG encoder 408 are B, MP
When the downstream position of the EG encoder 408 is C,
Water mark detection units 415, 415A and addition unit 40
6,406A can be arranged as follows.

When the watermark detection unit 415 is arranged in A, the addition unit 406 is A or B, and the addition unit 406A is C.
Can be placed at. That is, the watermark can be detected by A and remarked by A, B or C. The watermark detection unit 415 and the addition unit 4
The case where 06 is arranged in A corresponds to the configuration of FIG. 7. When the watermark detection unit 415 is arranged in B, the addition unit 406 can be arranged in B and the addition unit 406A can be arranged in C. That is, the watermark is detected by B, and B
Or it can be remarked with C. When the watermark detection unit 415A is arranged in C, the addition unit 406A
Can be placed at C. That is, the watermark can be detected by C and remarked by C. Note that this case corresponds to the configuration of FIG.

As described above, the watermark detecting section 41
5,415A and the addition units 406 and 406A have a total of 6 positional configurations.

-Fifth Embodiment- The fifth embodiment of the digital watermark embedding device of the present invention will be described below with reference to FIG.

FIG. 10 is a block diagram showing a digital watermark embedding device 501B according to the fifth embodiment. The digital watermark embedding device 501B re-embeds (remarks) a watermark in an MPEG stream in which the watermark has already been embedded, and reproduces the video content compressed and recorded by the MPEG in the recording medium. It can be used as part of the device.

As shown in FIG. 10, the digital watermark embedding device 501B detects the watermark from the input MPEG stream by the watermark detecting section 515.
A PN sequence generation unit 503 that generates a PN sequence that forms a watermark (digital watermark); and a PN sequence generation unit 5
03, an intensity setting unit 504 that amplifies the PN sequence and sets its intensity, an intensity changing unit 505 that changes the intensity of the PN sequence, the input MPEG stream and P
An adding unit 506 that adds N sequences, an MPEG decoder 508 that decodes an MPEG stream, a noise reduction unit 507 that reduces noise in a video signal, and an R
A storage unit 510 having an AM and a ROM, a display unit 511 for presenting predetermined information to the operator, an operation unit 512 for accepting the operation of the operator, and a control unit 514 for controlling the above units are provided. .

The watermark detection unit 515 indicates whether or not the watermark is embedded in the received MPEG stream, and whether the watermark embedded in the MPEG stream indicates one-generation copy permission or copy prohibition. Is detected and the detection result is detected by the control unit 5.
Output to 14.

If the watermark detection unit 515 detects a watermark indicating permission for one-generation copying, PN
The sequence generation unit 503 generates a PN sequence corresponding to copy inhibition. The intensity of the PN sequence is set by the intensity setting unit 504 as with the intensity setting unit 404 in the first embodiment, and the intensity is changed by the intensity changing unit 505. The PN sequence output from the intensity changing unit 505 is
The addition unit 506 adds the MPEG stream.

Under the control of the control unit 514, the intensity changing unit 505 changes the intensity of the watermark output from the intensity setting unit 504 in association with the intensity of the noise reduction processing in the noise reduction unit 507 to reduce noise. The higher the strength of the treatment, the higher the strength of the watermark. As shown in FIG. 10, the control unit 514 controls the noise reduction unit 507, and sends a control signal for controlling the intensity of noise reduction processing to the noise reduction unit 507. This control signal is also given to the intensity changing unit 505, and the amplification degree of the intensity changing unit 505 changes based on this control signal.

As a result, the intensity changing unit 505 is controlled by the control unit 514 to change the PN sequence output from the intensity setting unit 504, that is, the intensity of the watermark in association with the intensity of the noise reduction processing, The higher the strength of the noise reduction process, the higher the strength of the watermark. In this way, the digital watermark embedding device 501B can remark the watermark with such strength as to cancel the influence of the noise reduction processing in the noise reduction unit 507, so that the remarked watermark can be reliably detected. .

When the strength of the noise reduction process is increased, the image quality is often deteriorated. Therefore, in the portion where the strength of the noise reduction processing is increased, the image quality is often deteriorated originally by these processings. Therefore, even if the strength of the watermark is increased in such a portion, the image quality is deteriorated due to the watermark. Inconspicuous.

The period during which the intensity changing unit 505 increases the intensity of the watermark is a short period with a constant interval (constant time interval), for example, several frames (1 to 1) during the period when the intensity of the noise reduction processing is high. Only 3 frames) are enough. That is, the intensity changing unit 505 is controlled by the control unit 514 to intermittently increase the intensity of the watermark that reflects the intensity of the noise reduction processing by several frames. In this way, the watermark whose intensity is intermittently or pulse-likely increased is more inconspicuous on the image than the watermark which is increased over a period in which the intensity of the noise reduction process is high. Certainly detected.

The period during which the intensity changing unit 505 increases the intensity of the watermark is a random interval or an indefinite interval (random or indefinite time interval) according to some law during the period when the intensity of the noise reduction processing is high. Only the frame is enough. This is because the watermark becomes more inconspicuous in the image when it is increased at random intervals or indefinite intervals, compared to the case where the watermark is increased at regular intervals.

Furthermore, the period during which the intensity changing unit 505 increases the intensity of the watermark may be only a few frames in accordance with the change of the image during the period when the intensity of the noise reduction processing is high. For example, when there is a large change in the image over time, such as a scene change, when there is a large change in the image within a frame, such as an image with many strong edges, or when the motion vector is large. The watermark may be increased by a few frames at intense timing.

When the watermark detecting unit 515 does not detect the watermark indicating the first generation duplication permission and the watermark indicating duplication prohibition, since the content is permitted for duplication, the adding unit 506 remarks the watermark. It is output as a video signal without being processed.

When the watermark detection section 515 detects a watermark indicating that copying is prohibited, the control section 514 executes control for prohibiting reproduction.

Sixth Embodiment Hereinafter, with reference to FIG. 11, a sixth embodiment of the digital watermark embedding device of the present invention will be described. In FIG.
The same code | symbol is attached | subjected to the element corresponding to the structure of 5th Embodiment, and the description is abbreviate | omitted.

FIG. 11 is a block diagram showing a digital watermark embedding device 501C according to the sixth embodiment. The digital watermark embedding device 501C is for re-embedding (remarking) a watermark in a video signal in which a watermark has already been embedded. Like the digital watermark embedding device 501B, the digital watermark embedding device 501C compresses and records it on a recording medium by MPEG. It can be used as a part of a reproducing apparatus for reproducing the recorded video content.

As shown in FIG. 11, the digital watermark embedding device 501C generates a video signal by applying MPEG decoding by the MPEG decoder 508 and noise reduction by the noise reduction unit 507 to the input MPEG stream. A watermark detection unit 515A that detects a watermark from the.

The watermark detection unit 515A indicates whether or not the watermark is embedded in the received video signal, and whether the watermark embedded in the video signal is one-generation copy permission or copy prohibition. The detection result is output to the control unit 514.

When the watermark detecting section 515A detects the watermark indicating the permission of the first-generation copying, P
The N-series generation unit 503 generates a PN sequence corresponding to copy inhibition. The strength of this PN sequence is set by the strength setting section 504A, as in the strength setting section 404 in the first embodiment, and is further changed by the strength changing section 505A. PN output from the intensity changing unit 505A
The series is added to the video signal in addition section 506A.

Under the control of the control unit 514, the intensity changing unit 505A changes the intensity of the watermark output from the intensity setting unit 504A in association with the intensity of the noise reduction processing in the noise reduction unit 507 to reduce noise. The higher the strength of the treatment, the higher the strength of the watermark. As shown in FIG. 11, the control unit 514 controls the noise reduction unit 507, and sends a control signal for controlling the intensity of noise reduction processing to the noise reduction unit 507. This control signal is transmitted to the intensity changing unit 505A.
Is also given to the intensity changing unit 50 based on this control signal.
The amplification of 5 A changes.

As a result, the intensity changing unit 505A is controlled by the control unit 514 to change the PN sequence output from the intensity setting unit 504, that is, the intensity of the watermark in association with the intensity of the noise reduction processing, The higher the strength of the noise reduction process, the higher the strength of the watermark.

Thus, the digital watermark embedding device 50
1C decodes the MPEG stream by the MPEG decoder 508 and the noise reduction unit 50.
The noise reduction process of 7 is performed, and the PN series, that is, the watermark is superimposed on the generated video signal.
Here, in general, in order for the intensity of the noise reduction processing by the noise reduction unit 507 to be high, the image subjected to the noise reduction processing tends to be flat. For this reason,
If the intensity of the noise reduction processing continues to be high, the intensity of the watermark set in the intensity setting unit 504A may be kept low for a long time. However, as described above, since the strength changing unit 505A changes the strength of the watermark according to the strength of the noise reduction processing by the noise reduction unit 507, it is possible that the strength of the noise reduction processing continues to be high. However, the strength of the watermark is not kept low. Therefore, the watermark is reliably detected when the video content in which the watermark is embedded is reproduced.

The digital watermark embedding device 501C
Since the watermark is remarked after the decoding process and the noise reduction process that result in the deterioration of the watermark, the watermark is not deteriorated by the decoding process and the noise reduction process. Therefore, the digital watermark embedding device 501C has an advantage of being able to more appropriately manage the strength and state of the watermark embedded in the video signal.

If the watermark detecting unit 515A does not detect the watermark indicating the first generation duplication permission and the watermark indicating duplication prohibition, this content is the duplication permission, so the adding unit 506A remarks the watermark. It is directly output as a video signal without being processed.

When the watermark detection section 515A detects a watermark indicating that copying is prohibited, the control section 514 executes control for prohibiting reproduction.

Here, in the digital watermark embedding device 501B shown in FIG. 10, the watermark detection unit 515 is used.
The adder 506 is located upstream of the MPEG decoder 508. That is, the digital watermark embedding device 5
01B detects and remarks the watermark of the MPEG stream before being MPEG decoded. Further, the digital watermark embedding device 5 shown in FIG.
In 01C, the watermark detection unit 515A and the addition unit 506A are located on the downstream side of the noise reduction unit 507. That is, the digital watermark embedding device 5
01C detects and remarks the watermark of the video signal generated by performing MPEG decoding and noise reduction on the MPEG stream.

As described above, in the digital watermark embedding devices 501B and 501C shown in FIGS. 10 and 11, the noise reduction unit 507 and the MPEG decoder 508 are used.
With reference to the position of, the watermark detection and the watermark remarking are executed at the same position.

However, the digital watermark embedding device according to the present invention is not limited to such a configuration. For example, as shown in FIG. 12, the MPEG decoder 5
If the position on the upstream side of 08 is D, the position between the MPEG decoder 508 and the noise reduction unit 507 is E, and the position on the downstream side of the noise reduction unit 507 is F, the watermark detection units 515, 515A and the addition unit Fifty
6,506A can be arranged as follows.

When the watermark detection unit 515 is arranged in D, the addition unit 506 is D and the addition unit 506A is E or F.
Can be placed at. That is, the watermark can be detected by D and remarked by D, E or F. The watermark detection unit 515 and the addition unit 5
The case where 06 is arranged in D corresponds to the configuration of FIG. When the watermark detection unit 515 is arranged in E, the addition unit 506A can be arranged in E or F. That is, the watermark can be detected with E and remarked with E or F. Water mark detector 5
When 15A is arranged in F, the addition unit 506A can be arranged in F. That is, the watermark can be detected by F and remarked by F. Note that this case corresponds to the configuration of FIG. 11.

As described above, the watermark detection unit 51
5,515A and the addition units 506 and 506A have a total of 6 positional configurations.

In the above-described embodiment, the PN series forming the watermark is added to the brightness values set in the pixels of the image, but the present invention is not limited to this, and the watermark is not limited to this. The PN sequence constituting the above may be added to other values set in the pixels.

Further, the PN series forming the watermark is not limited to the M series. PNs that make up the watermark
As the sequence, another random sequence such as a Gold code may be used.

In the above embodiment, the case where the watermark is formed by the PN series has been described as an example, but the present invention is not limited to this. For example, it is possible to form the watermark by other signals in which codes are arranged such that random or near-random codes or codes having regularity cannot be easily judged even if they have regularity. is there.

In the above embodiment, the case where the codes forming the PN sequence and the pixels of the image correspond one-to-one has been described as an example, but the present invention is not limited to this. For example, the image may be divided into a plurality of regions composed of a plurality of pixels that are adjacent to each other, and the codes forming the PN sequence may be made to correspond one-to-one to the regions. Here, an example will be given in which the PN series “0101 ...”, which constitutes the watermark indicating that copying is prohibited, is embedded in an image divided into square areas each composed of four pixels connected to each other. In this case, "0" is added to all the luminance values of the four pixels included in the first arranged area of this image. Further, "1" is added to all the luminance values of the four pixels included in the second arranged area of this image. In this way, PN
By associating the codes forming the series with the regions made up of a plurality of pixels in a one-to-one correspondence, the watermark can remain in the digital image even if the digital image is filtered or compressed.

Of course, the present invention can be applied to not only broadcast media but also package media such as video tapes and DVDs.

[0113]

As described above, according to the digital watermark embedding apparatus of the present invention, the strength of the digital watermark to be embedded in the content is changed in association with the strength of the noise reduction processing by the noise reduction means. Even in the case of applying the watermark, the watermark can be embedded in a state in which the watermark can be reliably detected.

Further, according to the digital watermark embedding apparatus of the present invention, the strength of the digital watermark to be embedded in the content is changed in association with the compression strength of the compression coding processing by the compression coding means, so that the compression coding processing is performed. Even in such a case, the watermark can be embedded in a state where the watermark can be reliably detected.

Further, according to the digital watermark embedding method of the present invention, the strength of the digital watermark to be embedded in the content is changed in association with the strength of the noise reduction processing by the noise reduction procedure. Also,
The watermark can be embedded in a state where the watermark can be reliably detected.

Furthermore, according to the digital watermark embedding method of the present invention, the strength of the digital watermark to be embedded in the content is changed in association with the compression strength of the compression coding processing by the compression coding procedure. Even when it is applied, the watermark can be embedded in a state in which the watermark can be reliably detected.

Further, according to the recording medium having the digital watermark of the present invention, the strength of the digital watermark to be embedded in the content changes in association with the strength of the noise reduction processing. Also, the embedded watermark can be reliably detected.

Further, according to the recording medium having the digital watermark of the present invention, the strength of the digital watermark embedded in the content changes in association with the strength of the compression encoding process,
Even when the compression coding process is performed, the embedded watermark can be reliably detected.

[Brief description of drawings]

FIG. 1 is a block diagram showing a digital watermark embedding device according to a first embodiment.

FIG. 2 is a diagram illustrating a watermark.

FIG. 3 is a diagram illustrating a watermark.

FIG. 4 is a diagram showing a configuration of a PN sequence generation circuit.

FIG. 5 is a diagram showing a configuration of a PN sequence generation circuit.

FIG. 6 is a block diagram showing a digital watermark embedding device according to a second embodiment.

FIG. 7 is a block diagram showing a digital watermark embedding device according to a third embodiment.

FIG. 8 is a block diagram showing a digital watermark embedding device according to a fourth embodiment.

FIG. 9 is a diagram showing the positions of a watermark detection unit and an addition unit.

FIG. 10 is a block diagram showing a digital watermark embedding device according to a fifth embodiment.

FIG. 11 is a block diagram showing a digital watermark embedding device according to a sixth embodiment.

FIG. 12 is a diagram showing the positions of a watermark detection unit and an addition unit.

[Explanation of symbols]

404 Strength setting unit (changing means, setting means) 405 Strength changing unit (changing means, changing means) 414 Control unit (control means) 407 Noise reduction unit (noise reduction means) 408 MPEG encoder (compression encoding means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/91 H04N 5/91 P 5/92 5/92 H 7/081 F term (reference) 5B057 CB19 CE02 CE08 CG01 CH01 CH11 5C053 FA13 FA20 GB06 GB37 JA16 KA24 5C063 AA01 AB03 AB05 AC01 AC05 AC10 CA23 DA03 DA07 DA13 DB09 5C076 AA14 BA06 BA09 5J104 AA13 AA14 PA14

Claims (24)

[Claims] 1. A digital watermark embedding device for embedding a digital watermark composed of a signal generated based on a predetermined rule in a content composed of digital information, and a noise reduction means for performing noise reduction processing on the information of the content, Fluctuating means for fluctuating the strength of the digital watermark embedded in the content, and control means for controlling the fluctuating means so as to change the strength of the digital watermark in conjunction with the strength of noise reduction processing by the noise reducing means. An electronic watermark embedding device comprising: 2. The control means controls the changing means so as to increase the strength of the digital watermark when the strength of the noise reduction processing by the noise reduction means is high. The digital watermark embedding device described. 3. The changing means sets a strength of the digital watermark based on an information signal of the content, and a noise reducing means for reducing the strength of the digital watermark set by the setting means. 3. The digital watermark embedding apparatus according to claim 1, further comprising: a changing unit that changes so as to change in association with processing intensity. 4. A digital watermark embedding device for embedding a digital watermark composed of a signal generated based on a predetermined rule in a content composed of digital information, the compression coding means for compressing and coding the information of the content. Fluctuating means for changing the strength of the digital watermark embedded in the content, and controlling the changing means so as to change the strength of the digital watermark in conjunction with the compression strength of the compression encoding processing by the compression encoding means. A digital watermark embedding device comprising: a control unit. 5. The control means controls the varying means so as to increase the strength of the digital watermark when the compression strength of the compression coding processing by the compression coding means is high. Item 5. The electronic watermark embedding device according to Item 4. 6. The changing means sets a strength of the digital watermark based on an information signal of the content, and a strength of the digital watermark set by the setting means is compressed by the compression coding means. The electronic watermark embedding device according to claim 4 or 5, further comprising: a changing unit that changes so as to change in association with a compression strength of the encoding process. 7. The digital watermark embedding apparatus according to claim 1, wherein the control unit controls the changing unit so as to embed the digital watermark at intervals. 8. The control means comprises a detection means for detecting whether or not a first digital watermark is embedded in the content in advance, and a type of the content if the first digital watermark is embedded therein. The electronic watermark embedding device according to claim 1, wherein the electronic watermark embedding device controls to embed a new second electronic watermark based on a detection result from the detecting means. 9. The control means includes a detection means for detecting whether or not a first digital watermark is embedded in the content in advance, and a type of the content if the first digital watermark is embedded therein. 5. The digital watermark embedding device according to claim 4, wherein control is performed so as to embed a new second digital watermark based on a detection result from the detecting means. 10. The detecting means detects, from the information signal of the content, whether or not the first digital watermark is embedded and the type of the first digital watermark. Alternatively, the electronic watermark embedding device according to Item 9. 11. The detecting means detects whether or not the first digital watermark is embedded and the type of the first digital watermark from the information signal compression-coded by the compression-coding means. The electronic watermark embedding device according to claim 9, wherein 12. A digital watermark embedding method for embedding a digital watermark composed of a signal generated based on a predetermined rule in a content composed of digital information, the method comprising a noise reduction procedure for performing noise reduction processing on the information of the content. A variation procedure for varying the strength of the digital watermark embedded in the content, wherein the variation procedure changes the strength of the digital watermark in conjunction with the strength of noise reduction processing by the noise reduction procedure. How to embed digital watermark. 13. The digital watermark embedding method according to claim 12, wherein in the changing procedure, the strength of the digital watermark is increased when the strength of noise reduction processing by the noise reduction procedure is high. 14. The changing procedure comprises a setting procedure for setting the strength of the digital watermark based on an information signal of the content, and noise reduction by the noise reduction procedure for the strength of the digital watermark set by the setting procedure. 14. The method of embedding a digital watermark according to claim 12, further comprising: a changing procedure of changing so as to change in association with processing intensity. 15. A digital watermark embedding method for embedding a digital watermark composed of a signal generated based on a predetermined rule in a content composed of digital information, the compression coding procedure comprising compressing and coding information of the content. A changing procedure for changing the strength of the digital watermark embedded in the content, wherein the changing procedure changes the strength of the digital watermark in conjunction with the compression strength of the compression encoding process by the compression encoding procedure. A method for embedding a digital watermark characterized by: 16. The varying procedure increases the strength of the digital watermark when the compression strength of the compression coding processing by the compression coding procedure is high.
5. The method for embedding a digital watermark according to item 5. 17. The changing procedure comprises a setting procedure for setting the strength of the digital watermark based on the information signal of the content, and a compression of the strength of the digital watermark set by the setting procedure by the compression coding procedure. 17. A digital watermark embedding method according to claim 15 or 16, further comprising: a changing procedure for changing so as to change in association with the compression strength of the encoding process. 18. The digital watermark is embedded in the content at intervals.
Alternatively, the digital watermark embedding method according to Item 15. 19. A method of detecting whether or not a first digital watermark is embedded in the content in advance, and a type of detection when the first digital watermark is embedded, is provided. 13. The digital watermark embedding method according to claim 12, wherein the strength of a new second digital watermark to be embedded in the content is changed based on a detection result in the detection procedure. 20. A detection procedure for detecting whether or not a first digital watermark is embedded in the content in advance, and a type of the first digital watermark if the content is embedded, is provided. 16. The digital watermark embedding method according to claim 15, wherein the strength of a new second digital watermark to be embedded in the content is changed based on a detection result in the detection procedure. 21. The detection step detects whether or not the first digital watermark is embedded and the type of the first digital watermark from the information signal of the content. Alternatively, the digital watermark embedding method described in 20. 22. In the detection procedure, whether or not the first digital watermark is embedded and the type of the first digital watermark are detected from the information signal compressed and coded by the compression coding procedure. 21. The digital watermark embedding method according to claim 20, wherein: 23. Content comprising digital information,
A recording medium having a digital watermark, in which a video embedded with a digital watermark made of a signal generated based on a predetermined rule is recorded, wherein the content information is recorded after noise reduction processing, A recording medium having a digital watermark, wherein the strength of the watermark is changed in association with the strength of the noise reduction processing. 24. Content comprising digital information,
A recording medium having a digital watermark in which a video embedded with a digital watermark made of a signal generated based on a predetermined rule is recorded, wherein the content information is subjected to data compression processing by compression encoding and recorded. A recording medium having a digital watermark, wherein the strength of the digital watermark changes in association with the compression strength of the data compression processing.