JP2002354227A - Method and device for electronic watermark embedding processing and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for stably detecting an electronic watermark and carrying out electronic watermark embedding processing which can be hardly to be recognized in the normal observation state. SOLUTION: Characteristics of signal being an object of an electronic watermark embedding processing, for example, when the signal is the image, an analysis value of characteristics of an entire image (a), that of arbitrary area information of the image (b), that of the output from a filter processing part (c), or that of image characteristics in a temporal direction (d) are acquired, and a filter coefficient is determined on the basis of these analysis values, and a mark filter where the determined coefficient is set is generated, and convolutional operation between the generated mask filter and the signal being an object of electronic watermark embedding processing is carried out to set the embedding position and the embedding quantity of an electronic watermark.

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 prohibited).

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.

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.

[Embedding Digital Watermark] Various techniques have been proposed as digital watermarks applied to signals such as images. One typical digital watermark is a method based on data as an original signal, for example, a statistical property of an image, and a process of embedding a digital watermark based on the statistical property of the image will be described. It is assumed that an original image to be embedded with an electronic watermark is P, and an electronic watermark pattern to be embedded in the original image P is W. At this time, it is assumed that the digital watermark pattern W satisfies the following property.

[0011]

(Equation 1)

As an example, an original image P and a digital watermark pattern W are set as in the following equation. That is,

[0013]

(Equation 2)

However, in the above equation, for simplicity, the original image P
Is 5 × 4 pixels. In an image, adjacent pixels generally have a property of having close values, and therefore, each adjacent element of the original image P is set as a close value. In the example shown in [Equation 2], the size of the original image P and the digital watermark pattern W are set to be the same, but the sizes of the original image P and the digital watermark pattern W do not necessarily need to be the same. . If they are not the same size, an operation is performed on the portion where the original image and the digital watermark pattern overlap.

The digital watermark embedding process is executed based on the following equation.

[0016]

## EQU3 ## M = P + W

Here, M indicates an image in which a digital watermark pattern W is embedded in the original image P. The value of M is calculated as follows in the example shown in the above [Equation 2].

[0018]

(Equation 4)

[Digital Watermark Detection] The digital watermark pattern W is used for digital watermark detection. The detection of a digital watermark for the original image P in which the digital watermark W is not embedded is defined as shown below.

[0020]

S = P · W

Is defined as Here, the operator “·” is the inner product of the matrix, and s is the inner product value of the original image P and the digital watermark pattern W.

Since the sum of the elements of the digital watermark pattern is 0 (see [Equation 1]) and the neighboring pixels of the image tend to have generally close values, the inner product value s is close to 0. Value. In the example shown in [Equation 2] above,
The inner product value is as follows.

[0023]

(Equation 6)

Next, the same operation is performed on the image M in which the digital watermark is embedded. In the detection of the digital watermark for the image M in which the digital watermark W is embedded, the inner product value s' is obtained in accordance with the following equation, as described above.

[0025]

(Equation 7)

While the inner product value between the original image P and the digital watermark pattern W is a value close to 0, the inner product value s ′ between the image M with the embedded digital watermark and the digital watermark pattern W is
This is near the inner product value of the digital watermark pattern W itself. That is,

[0027]

[Equation 8] WW

The value is in the vicinity of the above equation [8]. The inner product value W · W can be used as a measure of the embedding strength of the digital watermark. When the target inner product value W · W when embedding the digital watermark pattern is large, the embedding strength of the digital watermark is expressed as “strong”, and when the inner product value W · W is small, the embedding strength of the digital watermark is expressed as “weak”. I do.

When the absolute value of the inner product value s of the original image P and the digital watermark pattern W and the inner product value s' of the digital watermark embedded image M and the digital watermark pattern W become large, the digital watermark is detected. The strength is expressed as “strong”, and when the absolute value of the inner product value s or the inner product value s ′ becomes a small value, the detection strength of the digital watermark is expressed as “weak”.

The correlation between the image and the digital watermark pattern is “large” or “high” when the detection strength of the digital watermark is high, and the correlation between the image and the digital watermark pattern is “high” when the detection strength of the digital watermark is low. Sometimes described as "small" or "low".

When the inner product value s of the original image P and the digital watermark pattern W, and the inner product value s ′ of the image M in which the digital watermark is embedded and the digital watermark pattern W are obtained in various images,
Those relative frequency distributions are represented by probability density functions f and f ′, and are as shown in FIG.

When determining whether or not a digital watermark is embedded in an image, the inner product value s of the digital watermark pattern W and the image P without the digital watermark is distributed around 0, and The fact that the inner product value s ′ between the image M in which is embedded and the digital watermark pattern W is distributed around W · W which is the inner product value of the digital watermark pattern W itself is used. An inner product value s "of the image whose digital watermark is to be confirmed and the digital watermark pattern W are obtained, and a comparison is made with respect to a certain threshold (th) to determine the presence or absence of the digital watermark pattern. Specifically, the following equation can be applied. It is.

[0033]

S "<th then no-watermark s" ≧ th then watermark

In the above equation, the inner product value s "of the image whose digital watermark is to be checked and the digital watermark pattern W is determined by the threshold value (t
h) If smaller, no digital watermark pattern is embedded. When the inner product value s "is equal to or larger than the threshold value (th), it indicates that it is determined that a digital watermark pattern is embedded, and FIG.

This threshold (th) is a value determined from the statistical properties of the probability density function f of the inner product value s and the probability density function f ′ of the inner product value s ′. The case where the digital watermark is not embedded but the threshold value (th) is exceeded, that is, the determination that the electronic watermark is embedded even though the electronic watermark is not embedded is called “false positive”. Conversely, the fact that the digital watermark is embedded but the threshold is not satisfied, that is, the determination that the digital watermark is not embedded despite the embedded digital watermark is called “false negative”.

"False positiv" which is such an erroneous judgment
e ”probability p _FP and“ false negative ”probability p
_{When the FN} is determined, the threshold (th) is determined. However, if the center position WW of the distribution of the probability density function f 'is not sufficiently large, it may be impossible to satisfy both the probability p _FP and the probability p _FN . Therefore, the process of embedding the digital watermark pattern W in the original image is changed from the above equation [Equation 3] to the following equation. That is,

[0037]

## EQU10 ## M = P + cW

Is changed to In the above equation, c is a non-negative scalar value. With this change, the embedding strength of the digital watermark is changed to the inner product value W · W of the digital watermark pattern W itself.
From cW · W multiplied by the scalar value.

In order to determine the threshold value, first, a probability p _FP and a probability p _FN required for an application using digital watermarking are determined, and a boundary value th _FP and a boundary value th _{FN at} that time are determined.
Is determined. At this time, it is necessary that the following expression is satisfied.

[0040]

[Equation 11] th _FP ≦ th _FN

Next, the center position cW · W of the probability density function f ′ is determined in consideration of the statistical properties of the probability density function f and the probability density function f ′ so as to satisfy the above expression th _FP ≦ th _FN . Finally, a threshold (th) is determined. The range that the threshold (th) can take is as shown in FIG.

When embedding the digital watermark pattern W in the original image P, the more the change to the original image P is made, that is, the larger the cW · W is, the greater the damage to the image is. Then, cW · W is the desired probability p _FP
And the probability p _FN , and the scalar value c is generally determined so that cW · W is minimized. That is, the relationship shown in the following equation is established. This is specifically the relationship shown in FIG.

[0043]

[Equation 12] th _FP = th _FN = th

Depending on the application using digital watermarking, extremely small values may be required for the probability p _FP and the probability p _FN . In particular, the requirement for the probability p _FP is significant. For example, when using a digital watermark for copyright protection,
This is because even if an illegally copied image is incorrectly determined to be a legitimate image, it is unlikely to lead to a user claim, whereas if a illegal image is incorrectly determined to be an illegally copied image, it is highly likely to lead to a user claim. . FIG. 5 shows an example in which the probability p _FP and the probability p _FN are smaller than those in the example of FIG.

Ideally, the probability p _FP and the probability p _FN are as close to 0 as possible. However, the threshold (t
When h) is defined, the strength cW · W of the digital watermark that must be embedded increases, and the effect of embedding 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.

While ensuring the reliability of the detection of the digital watermark,
Various techniques have been proposed to minimize the effect of digital watermarking on image quality. As a widely adopted basic method, there is a method of embedding strongly in an edge portion in an original image and embedding weakly in a flat portion. When the change of the pixel value is numerically the same, the change is noticeable in a flat part, but the change is not noticeable in an edge part. Even if the embedding strength of the digital watermark is varied between the edge part and the flat part, the reliability of detection of the digital watermark is almost the same if a certain amount of digital watermark pattern is embedded in the entire image. Becomes

[Embedding Information with Multiple Bits] The contents described so far are a method for embedding a digital watermark pattern in an image and a method for detecting the digital watermark. In this digital watermark embedding detection method, it is possible to determine only whether the digital watermark pattern is embedded in the image or not. In other words, only 1-bit information can be expressed. The following describes how to embed information in multiple bits.

The method of embedding multi-bit information in an image by digital watermark is roughly classified into a method using a plurality of digital watermark patterns, a method of dividing an image into small areas, and a combination of these.

In the method of using a plurality of digital watermark patterns, a method of expressing desired information by embedding exclusive digital watermarks with different meanings in each image and simultaneously overlaying the plurality of digital watermark patterns are described. Embedded in an image to express desired information by a combination thereof, and a method combining these two methods. FIG. 6 shows how a plurality of digital watermark patterns are embedded in the original image.

The method of expressing desired information by embedding exclusively in an image by giving each of a plurality of digital watermark patterns different meanings is necessary when the number of bits of information to be embedded in an image is b. The type n of the digital watermark pattern is n = ^2b . On the other hand, in a method in which a plurality of digital watermark patterns are simultaneously superimposed and embedded in an image to express desired information by a combination thereof, the required type n of the digital watermark pattern is n = b. However,
In the latter case, although the number of types of digital watermark patterns is small, an appropriate measure against image deterioration is often required because a plurality of digital watermark patterns are embedded in an image. Finally, in the method combining these two methods, the required type n of the digital watermark pattern is b ≦ n ≦ 2 ^b , which has the features of both methods.

The method of dividing an image into small areas is another method of embedding multi-bit information into an image by using a digital watermark. It is to make the watermark exist at the same time. Various methods of arranging the small areas have been proposed. Here, a description will be given of an example in which small areas are arranged in a grid pattern as shown in FIG. I and j in FIG. 7 are non-negative integers.

When dividing an image into small areas, the number of divisions becomes a problem. When the information to be embedded in the image is b bits, a method of dividing the image into b small regions is considered first. When embedding a digital watermark pattern in various images, the visual characteristics of the image are taken into consideration. This method is liable to cause a problem since a digital watermark pattern is often embedded. For example, strong against the edge of the embedded image,
When processing such as weak embedding in a flat part of an image is performed, if a small area corresponding to a certain bit happens to be a flat part, the digital watermark embedded in that area may not be detected. If there is an area in which digital watermark detection has failed even in one area, even if a digital watermark embedded in the remaining area is detected, the situation becomes meaningless as a whole combination. When an image is divided into small regions, dividing the image into smaller regions than b has the advantage that a digital watermark can be detected stably for various images. Even if the embedding strength of the digital watermark pattern is extremely weak in one small area, if the required amount of embedding of the digital watermark pattern is secured in the remaining small areas in which the same bit information is embedded, detection of the digital watermark as a whole is performed. It becomes possible.

FIG. 8 shows an example of dividing a small area when the embedded information is 8 bits. A plurality of small areas corresponding to the same bit are allocated in the image.

[Flow of Embedding Digital Watermark Pattern]
FIG. 9 shows an example of the configuration of a digital watermark pattern embedding processing device that executes a process of embedding a digital watermark pattern in an image. Hereinafter, a process of embedding a digital watermark pattern in an image will be described with reference to FIG.

An original image 901 is an image to be embedded with a digital watermark pattern, and is read from a storage medium such as a hard disk or a DVD,
Various images such as images supplied from an image capturing device such as a digital camera are included.

The digital watermark pattern generation unit 904 generates a digital watermark pattern based on the embedding information 902 to be embedded in the image and the digital watermark pattern generation key (key) in the digital watermark pattern generation key (key) storage unit 903. The embedded information 902 is various and arbitrary information such as the copy control information, the copyright information, and the editing information described above. The digital watermark pattern generation key (key) is, specifically, image division information when embedding a digital watermark pattern in an image, bit arrangement information, and the like.
02 is processing information required to generate 02 as a digital watermark pattern.

The digital watermark pattern embedding unit 905 embeds the digital watermark pattern generated by the digital watermark pattern generation unit 904 in the original image 901 as input data. It is this digital watermark pattern embedding unit 905 that adjusts the embedding strength of the digital watermark pattern in the edge portion and flat portion of the original image. The image in which the digital watermark pattern is embedded is a digital watermark embedded image 906.
Is output as

As described above, the digital watermark pattern generation unit 9
Numeral 04 denotes a digital watermark pattern generation key that expresses rules such as a method of dividing the embedded information 902 into small areas shown in FIG. 7 and a method of assigning small areas corresponding to bits of the embedded information shown in FIG. The digital watermark pattern is generated based on (key), and the digital watermark pattern embedding unit 905 adjusts the embedding strength according to the image and embeds the digital watermark pattern in the image.

[Digital Watermark Detection Flow] Next, FIG. 10 shows a configuration example of a digital watermark detection processing device for detecting a digital watermark from an image in which a digital watermark pattern is embedded.
Hereinafter, the digital watermark detection processing will be described with reference to FIG.

An image 1001 is a processing target image in which a digital watermark pattern is embedded.
Various images, such as images read from a storage medium such as a DVD or supplied via a communication medium, are included.

The digital watermark pattern generation unit 1003 generates a digital watermark pattern from the digital watermark pattern generation key (key) in the digital watermark pattern generation key (key) storage unit 1002. Digital watermark pattern generation key (key)
Are image division information when embedding a digital watermark pattern in an image, bit arrangement information, and the like, and are information necessary for detecting a digital watermark pattern.

The detecting section 1004 detects the digital watermark of the input image 1001 using the digital watermark pattern generated by the digital watermark pattern generating section 1003. In the detection processing, the correlation with the detection target image is obtained by the inner product value using the digital watermark pattern generated as described above, and the obtained inner product value is compared with the threshold (th) (see Expression 9). Execute. Further, when there is multi-bit information by digital watermark as described with reference to FIGS.
Acquires multi-bit information. Information detected by the detection unit 1004 is output as detection information 1005.

[0063]

As described above, for example, when embedding a digital watermark in image data, processing such as embedding strongly in an edge or a random portion of an embedded image and weakly embedding in a flat portion of the image is employed. Have been. This is because, when a digital watermark pattern is strongly embedded in a flat portion of an image such as the sky, the possibility that the digital watermark after embedding is visually recognized increases.

When a digital watermark is detected by a statistical method, the digital watermark component to be embedded must have a certain strength or more embedded in the signal. It is necessary to embed a digital watermark pattern in a signal so that the digital watermark pattern cannot be easily recognized while satisfying the condition that the digital watermark can be reliably detected.

Therefore, when embedding a digital watermark, it is necessary to extract, from the image information, a portion which is hardly perceived by a human. In the conventional method, a method of extracting a portion that is difficult to perceive on an image using a linear filter in consideration of human visual characteristics is used.

With reference to FIG. 11, a general processing method for extracting a part which is difficult to perceive on an image by using a linear filter and executing a digital watermark embedding process will be described. The upper part of FIG. 11 shows a digital watermark embedding processing configuration (Embedding), and the lower part shows a digital watermark detection processing configuration (Detecting).

The digital watermark embedding processing configuration (Em
In bedding, an image signal (Source Image) 101 to be embedded with a digital watermark is used as an input image, and a digital watermark pattern (Mask Image) 102 is embedded.

The image signal (Source Image) 101 uses an edge detection filter 103 such as a Laplacian filter to extract an area in which a digital watermark pattern is embedded. The edge detection filter 103 is one type of a linear filter in consideration of human visual characteristics, and extracts an edge of an image.
In the conventional digital watermark embedding processing apparatus, the shape of the filter for edge detection does not change temporally and spatially depending on an input image or other factors, and a filter having only one shape is used.

In the example shown in FIG. 1, an edge image is output by applying a 3 × 3 edge detection filter having a coefficient (-1, 8). The accumulating unit 104 calculates the edge area detected by the edge detection filter 103.
The integration with the digital watermark pattern generation information is executed. The integration unit 104 determines the embedding strength of the digital watermark pattern using the scaling parameter λ. By changing the scaling parameter λ, the embedding strength of the digital watermark pattern is changed. The digital watermark pattern generated by the accumulating unit 104 is superimposed on the image signal (Source Image) 101 by the adding unit 105 to output a digital watermark embedded image signal 106.

The image in which the digital watermark is embedded is processed by the digital watermark detection processing configuration (Detectin) shown in the lower part of FIG.
g) is detected. On the detection side, as described above, the correlation with the digital watermark pattern used for embedding, that is, the inner product is calculated to detect whether the digital watermark has been embedded. For example, the digital watermark detection target image 107 that has passed through the communication path is input, and the inner product p with the digital watermark pattern 108 used for embedding is
Calculated by the inner product calculation unit (Inner Product) 109,
The comparing means 110 determines whether or not the absolute value (abs (P)) of the calculated inner product value P has exceeded a certain value th.
When the absolute value (abs (P)) of the calculated inner product value P exceeds a certain value th, it is determined that the digital watermark is embedded (Detect). It is determined that embedding has not been performed (Not Detect).

However, the above-described digital watermark embedding method has a configuration in which the edge detection processing of an image to be digital watermark embedded is executed by applying only one edge detection filter. However, there are various types of images, such as an image having a large number of high-frequency regions that are messy as a whole, or an image having many low-frequency regions that are flat as a whole. In addition, in a moving image, there may be a case where a scene is switched between an image having many messy high frequency regions and an image having many flat low frequency regions.

When an edge detection process using the same shape filter is applied to such various images and an electronic watermark embedding process according to the detection is executed, depending on the image, an embedded electronic watermark pattern is usually used. May be perceived even in the image observation state. In the conventional method, since the coefficient of the edge detection filter does not change spatiotemporally, the edge detection processing becomes uniform, and it does not correspond to the visual recognition state in the human observation state, and it is necessary to embed a digital watermark No embedding,
Embedding was performed with excessive strength.

The present invention has been made in view of the above-described problems in the digital watermark embedding process, and analyzes the characteristics of an image to be embedded with a digital watermark in a spatiotemporal manner. By selecting and determining the embedding mode of the digital watermark, it becomes possible to embed a digital watermark according to the mode of the image, and from the image in which the digital watermark is embedded, it is difficult to recognize the digital watermark in a normal observation state, and It is an object of the present invention to provide a digital watermark embedding processing device and a digital watermark embedding processing method capable of maintaining a sufficient embedding amount for detection.

According to the configuration of the present invention, the linear filter is appropriately changed in accordance with the image characteristics, the characteristics of the image region, the filter output characteristics, or the time, and the amount of embedding of the digital watermark is adjusted. A digital watermark embedding processing device and a digital watermark embedding method that enable finely embedding a digital watermark in accordance with image characteristics and human vision are realized. Further, the configuration of the present invention can construct a system in a form added to a conventional digital watermark embedding processing apparatus.

In the configuration of the present invention, improvement of perceptual signal deterioration and increase in the amount of pattern embedding can be realized at the same time by devising a filter for extracting a portion that is difficult for a human to perceive from image information. By using a convolution operation of an appropriate mask filter and an image for the embedding process, the embedding position and intensity can be easily set.

[0076]

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 pattern embedding process, using a mask filter generating unit that generates a mask filter for performing a filtering process on a digital watermark embedding target signal, and a mask filter generated by the mask filter generating unit. Filter processing means for performing a filtering process on the digital watermark embedding target signal, a digital watermark pattern generation means for generating a digital watermark pattern based on an output of the filter processing means, and a digital watermark pattern generated by the digital watermark pattern generation means. Electronic watermark pattern embedding means for executing a process of embedding a digital watermark pattern in the electronic watermark embedding target signal, wherein the mask filter generating means converts analysis data obtained based on the digital watermark embedding target signal into In electronic watermark embedding processing apparatus characterized by having a configuration Zui be to generate different masks filter output to said filtering means.

Further, in one embodiment of the digital watermark embedding processing apparatus according to the present invention, the mask filter generating means includes (a) an overall characteristic, (b) a partial characteristic, or (c) of the digital watermark embedding processing target signal. A different mask filter is generated based on an analysis result of at least one of an output value from the filter processing unit or (d) a characteristic in a time direction, and is output to the filter processing unit.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, when the signal to be subjected to the digital watermark embedding processing is an image, the mask filter generating means includes: (a) an overall image characteristic; And (c) generating a different mask filter based on the analysis result of at least one of the characteristics of the partial region, or (c) the output value from the filter processing unit, and (d) the characteristics in the time direction of the moving image. It is characterized by having a configuration for outputting to means.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the digital watermark embedding processing apparatus further executes a frequency analysis of an image to be subjected to the digital watermark embedding processing, and performs an analysis on an image having many high frequency components. Image characteristic detecting means for determining whether the image is an image having a large number of low frequency components, wherein the mask filter generating means has a configuration for generating a different mask filter based on a detection result of the image characteristic detecting means. It is characterized by.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the digital watermark embedding processing apparatus further includes an image area information detecting means for acquiring area division information of an image to be subjected to digital watermark embedding processing. Wherein the mask filter generating means has a configuration for generating a different mask filter based on a detection result of the image area information detecting means.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the image area information detecting means obtains area division information in which a central area and a peripheral area of an image are divided step by step. The mask filter generation unit is configured to set the amount of embedding of the electronic watermark in the image central region to be small and to be large in the image peripheral region based on the stepwise division information acquired as the detection result of the image region information detection unit. Characterized in that it has a configuration for generating different mask filters.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the digital watermark embedding processing apparatus further includes an image area information detecting means for acquiring area division information of an image to be subjected to digital watermark embedding processing. The digital watermark pattern generation unit applies a different scaling parameter λ based on the detection result of the image area information detection unit, and integrates the output result of the filter processing unit and the digital watermark pattern generation information. It is characterized in that it has a configuration to execute and generate a digital watermark pattern.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the mask filter generating means includes a filter output image I (x, y) obtained as a result of performing a filter processing in the filter processing means.
Is performed, and when the high-frequency component amount included in the filter output image I (x, y) is equal to or less than a predetermined threshold, a regenerated mask filter in which the mask filter coefficient is changed is generated to perform the filtering process. Means, and the filter processing means executes a filtering process to which the regeneration mask filter is applied, and outputs a filtered output image I (x,
On the condition that the edge amount included in y) becomes larger than the threshold value, a digital watermark pattern generation process is performed based on the filter output image I (x, y).

Further, in one embodiment of the digital watermark embedding processing device of the present invention, the digital watermark embedding processing device further includes a spatio-temporal analysis processing means for analyzing a spatio-temporal region characteristic of an image to be subjected to digital watermark embedding processing. Wherein the mask filter generation means generates a different mask filter based on the analysis result of the spatiotemporal analysis processing means.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the spatio-temporal analysis processing means performs frequency analysis on a plurality of frames of the moving image to be subjected to the digital watermark embedding processing to include the moving image in the moving image. And a mask filter generation unit configured to generate a different mask filter according to frequency component information of a plurality of frames of a moving image obtained as an analysis result of the spatiotemporal analysis processing unit. It is characterized by.

Further, in one embodiment of the digital watermark embedding processing apparatus of the present invention, the mask filter generating means is configured to generate a small area based on analysis data obtained based on information of each small area of the digital watermark embedding target signal. It is characterized by having a configuration for generating a different mask filter for each.

Further, a second aspect of the present invention is a digital watermark embedding method for executing a digital watermark pattern embedding process, and a mask filter generating step for generating a mask filter for filtering a digital watermark embedding target signal. A filter processing step of performing a filtering process on the digital watermark embedding target signal using the mask filter generated in the mask filter generation step; and a digital watermark pattern for generating a digital watermark pattern based on an output in the filter processing step A digital watermark pattern embedding step of executing a process of embedding the digital watermark pattern generated in the digital watermark pattern generation step in the digital watermark embedding target signal. The digital filter embedding method includes a step of generating a different mask filter based on the analysis data acquired based on the digital watermark embedding target signal and outputting the generated mask filter to a filter processing unit. .

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the mask filter generating step includes the steps of (a) overall characteristics, (b) partial characteristics, and (c) of the digital watermark embedding processing target signal. A different mask filter is generated based on an analysis result of at least one of an output value from the filter processing unit and (d) a characteristic in a time direction.

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the mask filter generating step includes the steps of: (a) determining the overall characteristics of the image; And (c) generating a different mask filter based on an analysis result of at least one of the characteristics of the partial region, or (c) the output value from the filter processing unit, and (d) the characteristics in the time direction of the moving image. I do.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the digital watermark embedding processing method further executes a frequency analysis of an image to be subjected to the digital watermark embedding processing, and performs the processing on an image having many high frequency components. An image characteristic detecting step of determining whether the image is an image having many low frequency components, wherein the mask filter generating step generates different mask filters based on a detection result in the image characteristic detecting step. I do.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the digital watermark embedding processing method further includes an image area information detecting step of acquiring area division information of an image to be subjected to digital watermark embedding processing. Wherein the mask filter generating step generates different mask filters based on a detection result of the image area information detecting step.

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the image area information detecting step obtains area division information in which a central area and a peripheral area of an image are divided in stages. The mask filter generating step is configured such that the embedding amount of the electronic watermark is small in the image central region and large in the image peripheral region based on the stepwise division information obtained as the detection result of the image region information detecting step. And generating different mask filters.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the digital watermark embedding processing method further includes an image area information detecting step of acquiring area division information of an image to be subjected to digital watermark embedding processing. The digital watermark pattern generation step applies a different scaling parameter λ based on the detection result of the image area information detection step, and integrates the output result of the filter processing means and the digital watermark pattern generation information. It is characterized in that the digital watermark pattern is executed to generate a digital watermark pattern.

Further, in one embodiment of the digital watermark embedding processing method according to the present invention, the mask filter generating step includes a step of generating a filter output image I obtained as a result of performing the filter processing in the filter processing step.
(X, y) is evaluated, and the filter output image I (x, y) is evaluated.
If the high-frequency component amount included in y) is equal to or less than a predetermined threshold, a regenerated mask filter in which the coefficients of the mask filter are changed is generated and output to the filter processing means. A filtering process using a synthetic mask filter is performed, and the filter output image I (x, y) is filtered on the condition that the edge amount included in the filter output image I (x, y) becomes larger than a threshold value.
The digital watermark pattern generation processing is performed based on (x, y).

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the digital watermark embedding processing method further comprises a spatiotemporal analysis processing step of analyzing a spatiotemporal region characteristic of an image to be subjected to the digital watermark embedding processing. Wherein the mask filter generating step generates different mask filters based on the analysis result of the spatiotemporal analysis processing step.

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the spatio-temporal analysis processing step is performed by performing frequency analysis on a plurality of frames of the moving image to be subjected to the digital watermark embedding processing to include the moving image in the moving image. Performing a frequency component analysis, wherein the mask filter generating step generates different mask filters according to frequency component information of a plurality of frames of a moving image obtained as an analysis result of the spatiotemporal analysis processing step. I do.

Further, in one embodiment of the digital watermark embedding processing method of the present invention, the mask filter generating step includes the step of generating a small area based on analysis data obtained based on information of each small area of the digital watermark embedding target signal. A different mask filter is generated every time.

Further, a third aspect of the present invention is a program for causing a computer system to execute a digital watermark pattern embedding process, the mask filter generating a mask filter for performing a filtering process on a digital watermark embedding target signal. A generating step; a filtering step of performing a filtering process on the digital watermark embedding target signal using the mask filter generated in the mask filter generating step; and an electronic device for generating a digital watermark pattern based on an output in the filtering process step. A watermark pattern generating step, and a digital watermark pattern embedding step of executing a process of embedding the digital watermark pattern generated in the digital watermark pattern generating step in the digital watermark embedding target signal. Wherein the mask filter generating step includes a step of executing a step of generating a different mask filter based on the analysis data acquired based on the digital watermark embedding target signal and outputting the mask filter to a filter processing unit. There is in the program.

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 storage medium of the present invention is a medium that provides a computer program in a computer-readable format to a general-purpose computer system that can execute various program codes, for example. . 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 operation 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.

[0102]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a digital watermark embedding processing apparatus according to the present invention will be described below with reference to the drawings. In the following embodiment, an image signal is mainly described as an example of a signal to be subjected to digital watermark embedding processing. However, the present invention is not limited to an image signal, and is applicable to other types of signals such as an audio signal. It is possible.

FIG. 12 shows the configuration of the first embodiment of the digital watermark embedding processing apparatus of the present invention. The digital watermark embedding processing apparatus according to the present invention includes an image characteristic of an original image to be embedded with a digital watermark, or a characteristic of each region constituting the image,
Alternatively, it is an electronic watermark embedding processing device using a filter that changes according to filter output characteristics or time.

The configuration of the digital watermark embedding processing apparatus shown in FIG. 12 will be described. The original image 201 is an image to be embedded with a digital watermark pattern, and includes various images such as an image read from a storage medium such as a hard disk or a DVD, or an image supplied from an image capturing device such as a scanner or a digital camera. It is.

The filter processing unit 203 executes a filtering process on the original image 201 using the mask filter generated by the mask filter generation unit 202 based on the original image 202 and other information. Specifically, the mask filter generated by the mask filter generation unit 202 and the original image 201
Execute the convolution operation with. Mask filter generator 2
02, (a) the characteristics of the entire image of the original image, (b) arbitrary area information of the original image, (c) output from the filter processing unit, or (d) analysis of the characteristics of the image in the time direction. By doing so, a filter configuration to be applied, for example, a filter coefficient is determined, and a mask filter having the determined configuration is generated. Each of these aspects will be described later. The filter processing unit 203 performs a convolution operation with the original image 201 using the mask filter generated by the mask filter generation unit 202.

The mask filter generation unit 202 can cope with a case where the processing target signal is not an image such as an audio signal, and the (a) overall characteristic of the digital watermark embedding processing target signal or (b) Partial characteristics, or (c)
A filter configuration to be applied, for example, a filter coefficient is determined based on an output value from the filter processing unit or (d) a result of analysis of at least one of characteristics in a time direction, and a mask filter having the determined configuration is generated. .

The digital watermark pattern generation unit 205 generates a digital watermark pattern based on the embedding information 206 to be embedded in the image and the digital watermark pattern generation key (key) in the digital watermark pattern generation key (key) storage unit 204. The embedding information 206 is various, such as copy control information, copyright information, and editing information, and is arbitrary information.
The digital watermark pattern generation key (key) is, specifically, image division information when embedding a digital watermark pattern in an image, bit arrangement information, and the like, and is necessary for generating the embedded information 206 as a digital watermark pattern. Processing information.

The digital watermark pattern embedding section 207 embeds the digital watermark pattern generated by the digital watermark pattern generating section 206 into the original image 201 as input data. The image in which the digital watermark pattern is embedded is output as a digital watermark embedded image 208.

The digital watermark pattern generation unit 205
Is a digital watermark pattern generation key expressing rules such as a method of dividing the embedded information 206 into small areas of the image shown in FIG. 7 and a method of assigning small areas corresponding to the bits of the embedded information shown in FIG. The digital watermark pattern is generated based on (key), and the digital watermark pattern embedding unit 207 embeds the digital watermark pattern in the image.

FIG. 13 shows a processing flow of the digital watermark pattern embedding processing apparatus shown in FIG. First, in step S301, a digital watermark pattern is generated from information to be embedded in a digital watermark and a digital watermark pattern generation key (key).

In step S302, an original image into which a digital watermark is to be embedded is input. In step S303, the characteristics of the image are analyzed based on (a) the characteristics of the entire image of the original image, (b) arbitrary area information of the original image, (c) the output of the filter, or (d) the time direction. Is performed, the filter coefficient is determined, and a convolution operation is performed on the image using the determined coefficient.

In step S304, a digital watermark pattern is embedded according to the amplitude output in step S303. In step S305, the image in which the digital watermark pattern is embedded is output as a digital watermark embedded image.

In the digital watermark embedding processing apparatus of the present invention, (a) the characteristics of the entire image of the original image to be subjected to the digital watermark embedding processing, (b) arbitrary area information of the original image, and (c)
The output of the filter processing unit or (d) the characteristics of the image are analyzed in the time direction to determine the filter coefficients, and a mask filter in which the determined coefficients are set is generated. By executing the convolution operation with the image, the embedding position and the embedding amount of the digital watermark are specified. Hereinafter, embodiments of the digital watermark embedding processing apparatus according to the present invention which are distinguished for each generation mode of the mask filter will be described.

[Determination of Filter Coefficient Using Characteristics of Entire Image] First, an embodiment of a digital watermark embedding processing apparatus for determining a filter coefficient based on image characteristics of an original image to be subjected to digital watermark embedding processing will be described. This will be described with reference to FIG. Here, the image characteristics refer to the frequency of the entire image or a part of the image to be subjected to the digital watermark embedding process, the output state of a certain evaluation function, and the like.

The configuration of the digital watermark embedding processing apparatus shown in FIG. 14 will be described. The original image 401 is an image to be embedded with a digital watermark pattern, and includes various images such as an image read from a storage medium such as a hard disk or a DVD, or an image supplied from an image capturing device such as a scanner or a digital camera. It is.

The filter processing unit 404 executes a convolution operation between the mask filter generated by the mask filter generation unit 403 and the original image 401 based on the image characteristics of the original image 401. The mask filter generation unit 403 determines filter coefficients based on the analysis result information of the frequency of the entire image or a part of the original image output from the image characteristic detection unit 402 or the output state of a certain evaluation function, and determines the determined coefficients. Generate the set mask filter. Filter processing unit 404
Performs a convolution operation with the original image 401 using the mask filter generated by the mask filter generation unit 403.

The digital watermark pattern generation unit 406 stores the embedding information to be embedded in the image and the digital watermark pattern generation key (k) in the digital watermark pattern generation key (key) storage unit 405.
ey) to generate a digital watermark pattern based on The embedding information is various, such as, for example, copy control information, copyright information, and editing information, and is arbitrary information. The digital watermark pattern generation key (key) is, specifically, image division information when embedding a digital watermark pattern in an image, bit arrangement information, and the like, and is a process required to generate embedded information as a digital watermark pattern. Information.

The digital watermark pattern embedding section 407 embeds the digital watermark pattern generated by the digital watermark pattern generating section 406 into the original image 401 as input data. The image in which the digital watermark pattern is embedded is output as a digital watermark embedded image 408.

The digital watermark pattern generation unit 406
Is a digital watermark pattern generation key (for example, a method of dividing the embedded information into small areas of the image shown in FIG. 7 and a method of assigning a small area corresponding to the bits of the embedded information shown in FIG. 8). key), the digital watermark pattern is generated, and the digital watermark pattern embedding unit 4 is executed.
07 embeds the digital watermark pattern in the image.

FIG. 15 shows a specific example of an analysis process for the characteristics of the entire image, a process of determining a filter coefficient using the analysis result, and a process of generating a mask filter, which are executed in the image characteristic detection unit 402 and the mask filter generation unit 403. It will be described using FIG.

The image characteristic detection unit 402 samples the original image 401 to be subjected to the digital watermark embedding process at a fixed period, and performs an FFT (Fast Fourie Transform: Fast Fourier Transform) on the image (FIG. 15- (1)). )).

The evaluation method will be briefly described. When the low-frequency component is centered on the frequency plane f (u, v),
Let r be its radial axis. On the other hand, the following function is defined (FIG. 15- (2)).

[0123]

(Equation 13)

The function g (r) expresses the spatial frequency distribution of the image in one dimension. Next, a threshold th, which is the r-axis of the function g (r), is taken, and an average value is taken at higher and lower frequencies (FIG. 15- (3)). High frequency average value (ave_
high) and the low frequency average value is (ave_low). The graph shown in FIG. 15 (3) shows the frequency on the horizontal axis and g (r) (Power) on the vertical axis for the FFT image of the input image.

If the high frequency average value (ave_high) is lower than the low frequency average value (ave_low), it is determined that the image has more low frequency components. When embedding a large amount of digital watermark and strong intensity into an image with many low-frequency components, the digital watermark pattern can be recognized in a normal image observation state, depending on the shape of the digital watermark pattern to be embedded. The nature becomes high.

Therefore, the image characteristic detecting unit 402 determines the high frequency average value (ave_high) and the low frequency average value (av
e_low) (FIG. 15- (4)).

When the high frequency average value (ave_high) is lower than the low frequency average value (ave_low), the mask filter generation unit 403 generates or selects and applies a 3 × 3 mask filter. The filter processing unit 404 performs edge detection by performing a convolution operation between the 3 × 3 mask filter generated by the mask filter generation unit 403 and the original image 401 (FIG. 15- (5)), and performs digital watermarking. The embedding amount for the image is controlled to be small.

On the other hand, when it is determined that the high-frequency average value (ave_high) is higher than the low-frequency average value (ave_low) and the image has many high-frequency components, the mask filter generation unit 403 outputs the 5 × 5 image. A mask filter is generated or selected and applied to the filter processing unit 404 and output to the filter processing unit 404. The filter processing unit 404 performs edge detection by a convolution operation between the 5 × 5 mask filter generated by the mask filter generation unit 403 and the original image 401. (FIG. 15- (6))
The embedding amount of the digital watermark in the image is controlled to be relatively large.

As described above, in the digital watermark embedding processing apparatus according to the present embodiment, an image having many high frequency components or an image having many low frequency components is determined by analyzing the characteristics of the image to be subjected to the digital watermark embedding process, for example, the frequency analysis of the image. The configuration is such that different mask filters are generated depending on whether the edge detection process is performed, edge detection processing is performed by convolution with the input image, and digital watermark embedding processing is performed on the detected part. Digital watermark embedding processing, i.e., a process of embedding a large amount of digital watermark in an image with many high frequency components and embedding a small amount of digital watermark in an image with many low frequency components, is possible. Corresponding electronic watermark embedding control becomes possible.

[Extracting a Partial Region of the Input Image and Determining a Filter Coefficient According to the Region Characteristics] Next, a partial region of the input image to be subjected to the digital watermark embedding process is extracted and a filter coefficient is determined according to the region characteristics. An embodiment of the embedding processing device will be described with reference to FIG. Note that the characteristics here include a frequency in an image cut out into an arbitrary region, an output state of a certain evaluation function, and the like.

The structure of the digital watermark embedding processing apparatus shown in FIG. 16 will be described. The original image 501 is an image to be embedded with a digital watermark pattern, and includes various images such as an image read from a storage medium such as a hard disk or a DVD or an image supplied from an image capturing device such as a scanner or a digital camera. It is.

The filter processing unit 504 includes the mask filter generated by the mask filter generation unit 503 based on the area characteristics of the area forming the image of the original image 501 and the original image 50.
Perform a convolution operation with 1. The mask filter generation unit 503 determines one or a plurality of filter coefficients for one area based on the frequency of the entire image or a part of the image output from the image area information detection unit 502, the output state of a certain evaluation function, and the like. Generate a mask filter with coefficients set. The filter processing unit 504 uses the mask filter generated by the mask filter generation unit 503 to generate the original image 50.
Perform a convolution operation with 1.

The digital watermark pattern generation unit 506 stores the embedding information to be embedded in the image and the digital watermark pattern generation key (k) in the digital watermark pattern generation key (key) storage unit 505.
ey) to generate a digital watermark pattern based on The embedding information is various, such as, for example, copy control information, copyright information, and editing information, and is arbitrary information. The digital watermark pattern generation key (key) is, specifically, image division information when embedding a digital watermark pattern in an image, bit arrangement information, and the like, and is a process required to generate embedded information as a digital watermark pattern. Information.

The digital watermark pattern embedding section 507 embeds the digital watermark pattern generated by the digital watermark pattern generating section 506 into the original image 501 as input data. The image in which the digital watermark pattern is embedded is output as a digital watermark embedded image 508.

The digital watermark pattern generation unit 506
Is a digital watermark pattern generation key (for example, a method of dividing the embedded information into small areas of the image shown in FIG. 7 and a method of assigning a small area corresponding to the bits of the embedded information shown in FIG. 8). key), the digital watermark pattern is generated, and the digital watermark pattern embedding unit 5 is executed.
07 embeds the digital watermark pattern in the image.

The image area information detecting section 502, the mask filter generating section 503, the filter processing section 504, and the digital watermark pattern generating section 506 perform analysis processing on image area characteristics, determine filter coefficients using the analysis results, and perform processing. Processing examples such as mask filter generation processing and edge detection processing as filter processing on the original image will be described with reference to FIG.

The upper part (a) of FIG. 17 is a diagram for explaining a process of changing the coefficient of the mask filter generated by the mask filter generator 503 based on the image area characteristics of the image to be embedded with a digital watermark. The lower part (b) of
The digital watermark pattern generation unit 506 changes the scaling parameter λ based on the image area characteristic of the digital watermark embedding target image, and integrates the edge area detected by the filter processing unit 504 with the digital watermark pattern generation information. FIG. 9 is a diagram illustrating a process of changing the embedding strength of a digital watermark pattern by executing the process.

First, the process of changing the coefficient of the mask filter generated by the mask filter generation unit 503 based on the image area characteristics of the digital watermark embedding target image in FIG. 17A will be described.

[0139] The image area information detecting section 502 cuts out a partial area of the input image and executes processing for detecting the characteristics of the area. The image area information detecting unit 502 sets a pyramid-shaped pyramid-shaped function f (x, y) having the same size as the frame of the input image for the input image (FIG. 17- (a1)). The pyramidal function f (x, y) is the height around the image (y)
Is smaller, and the height (y) increases as the position approaches the center of the image. Although the example of FIG. 17 has a three-stage configuration, the number of stages can be set to various numbers according to, for example, the size of an image.

For example, in the case of a video used for broadcasting, a person's face or the like often comes at the center, so that it is not preferable that a strong digital watermark pattern is placed on the center of the image. Therefore, it is preferable to reduce the strength of the digital watermark at the center of the image. Therefore, the gain of the filter is calculated as the reciprocal of the pyramidal pyramidal function f (x, y), that is, 1 /.
Set to f (x, y).

The mask filter generation unit 503 calculates the reciprocal 1 / f of a pyramid-shaped pyramidal function f (x, y) having the same size as the frame of the input image generated by the image area information detection unit 502.
Mask filter M (u, v) preset at (x, y)
Is multiplied according to the image area, a mask filter having a gain according to the image area is generated, and output to the filter processing unit 504.

Since 1 / f (x, y) takes a smaller value in the central part of the image than in the peripheral part of the image, as a result, the embedding of the digital watermark is made stronger in the peripheral part of the image. The mask filter M (u, v) / f (x, y) is set and output to the filter processing unit 504. At the center of the image, the mask filter M for weakening the electronic watermark is set.
(U, v) / f (x, y) is set and output to the filter processing unit 504 (FIG. 17- (a2)).

The filter processing unit 504 performs a convolution operation with the input image based on the mask filter M (u, v) / f (x, y) corresponding to the image area output from the mask filter generation unit 503. Execution (FIG. 17- (a3)) and output to the digital watermark pattern generation unit 506. The convolution operation with the input image performed by the filter processing unit 504 is performed by a mask filter M (u, v) / f corresponding to the image area output from the mask filter generation unit 503.
This is executed based on (x, y). As a result, edges that are weaker in the image periphery than in the image center are also detected, and more digital watermarks are embedded in the image periphery.

FIG. 17B shows a case where the scaling parameter λ is changed in the digital watermark pattern generation unit 506 based on the image area characteristics of the image to be embedded, and the edge area detected in the filter processing unit 504 is changed. FIG. 7 is a diagram for explaining a process of changing the embedding strength of a digital watermark pattern by executing integration with digital watermark pattern generation information.

The image area information detecting section 502 cuts out a partial area of the input image and executes processing for detecting characteristics of the area. The image area information detection unit 502 sets a pyramid-shaped pyramidal function f (x, y) having the same size as the frame of the input image for the input image (FIG. 17- (b1)). The pyramidal function f (x, y) is the height around the image (y)
Is smaller, and the height (y) increases as the position approaches the center of the image. Here, the height (y) corresponds to the reciprocal 1 / λ of the scaling parameter λ. Note that the pyramid-shaped pyramidal function f (x, y) is expressed as
Although it has a three-stage configuration, the number of stages can be set to various numbers according to, for example, the size of an image.

The filter processing unit executes a convolution operation with the input image using a uniform mask filter M (u, v) in all image regions (FIG. 17- (b2)) to generate a digital watermark pattern. Output to the unit 506.

The digital watermark pattern generation unit 506 determines the value of the pyramid-type pyramid function f (x, y) input from the image area information detection unit 502 as 1 according to the image area.
/ Λ is calculated, the scaling parameter λ is calculated, the calculated scaling parameter λ is applied, and the edge area detected by the filter processing unit 504 is integrated with the digital watermark pattern generation information to perform digital watermarking. A pattern is generated (FIG. 17- (b3)). The value of the scaling parameter λ is small at the center of the image and large at the periphery of the image. As a result, more digital watermarks are embedded in the periphery of the image than in the center of the image.

The filter coefficient changing process shown in FIG. 17A and the scaling parameter λ changing process shown in FIG. 17B may be configured to execute only one of them. It may be.

As described above, in the digital watermark embedding processing apparatus of this embodiment, different mask filters are used depending on the area characteristics of the image to be subjected to the digital watermark embedding processing, for example, whether the image is at the center or at the periphery of the image. Since it is configured to generate and perform edge detection processing by convolution with an input image and to perform processing for embedding a digital watermark in a detected portion, digital watermark embedding processing according to the image area, for example, It is possible to embed a large amount of digital watermark in a part and embed a small amount of digital watermark in the center of the image, and it is possible to control digital watermark embedding corresponding to visual perception of digital watermark.

In the digital watermark embedding processing apparatus of this embodiment, a different scaling parameter λ is changed according to the area characteristic of the image to be subjected to the digital watermark embedding processing, for example, whether the image is at the center or at the periphery of the image. The digital watermark pattern is generated by performing integration with the digital watermark pattern generation information, so that a digital watermark embedding process according to the area of the image, for example, a large amount of digital watermark is embedded in the peripheral portion of the image In addition, a process of embedding a small amount of digital watermark in the center of the image becomes possible, and digital watermark embedding control corresponding to visual perception of digital watermark becomes possible.

[Changing Filter Coefficients Using Output of Filter] Next, the output of a filter processing unit that performs edge detection by applying a mask filter to an input image to be subjected to digital watermark embedding processing is fed back. An embodiment of a digital watermark embedding processing device for changing a filter coefficient will be described with reference to FIG. In the digital watermark embedding processing apparatus of the present embodiment, the mask filter generation unit 602 shown in FIG. 18 previously holds a filter coefficient determined as an initial value, and uses an image obtained by performing a filter process in the filter processing unit 603. Thus, a process of changing the value of the filter coefficient is executed.

A configuration of the digital watermark embedding processing apparatus shown in FIG. 18 will be described. The original image 601 is an image to be embedded with a digital watermark pattern, and includes various images such as an image read from a storage medium such as a hard disk or a DVD, or an image supplied from an image capturing device such as a scanner or a digital camera. It is.

The filter processing unit 603 includes the mask filter generated by the mask filter generation unit 503 and the original image 601.
Execute the convolution operation with. Mask filter generator 6
In step 02, a mask filter in which the filter coefficient is converged to a certain value is regenerated using an evaluation function for determining the filter coefficient by feeding back the output of the filter processing unit 603. The filter processing unit 603 performs filter processing on the image using the regenerated mask filter.

The mask filter regenerating process in the mask filter generating unit 602 is performed on each of the divided areas of the original image 601 which is an image to be embedded with a digital watermark, to generate a mask filter for each area. It may be configured.

The digital watermark pattern generation unit 605 includes the embedding information to be embedded in the image and the digital watermark pattern generation key (k) in the digital watermark pattern generation key (key) storage unit 604.
ey) to generate a digital watermark pattern based on The embedding information is various, such as, for example, copy control information, copyright information, and editing information, and is arbitrary information. The digital watermark pattern generation key (key) is, specifically, image division information when embedding a digital watermark pattern in an image, bit arrangement information, and the like, and is a process required to generate embedded information as a digital watermark pattern. Information.

The digital watermark pattern embedding section 606 embeds the digital watermark pattern generated by the digital watermark pattern generation section 605 into the original image 601 as input data. The image in which the digital watermark pattern is embedded is output as a digital watermark embedded image 607.

The digital watermark pattern generation unit 605
Is a digital watermark pattern generation key (for example, a method of dividing the embedded information into small areas of the image shown in FIG. 7 and a method of assigning a small area corresponding to the bits of the embedded information shown in FIG. 8). key), and generates a digital watermark pattern based on the digital watermark pattern.
06 embeds the digital watermark pattern in the image.

An example of the processing configuration of the mask filter regenerating process by the feedback of the output data of the filter processing unit executed in the mask filter generating unit 602 and the filter processing unit 603 will be described with reference to FIG.

FIG. 19 shows an example of a configuration in which mask filters are regenerated by applying different evaluation functions to the output of the filter generator in the upper and lower stages.

The description starts from the configuration of FIG. The mask filter generation unit 602 previously holds the filter coefficient determined as the initial value, and the filter processing unit 603 first performs a convolution operation on the input image by applying a mask filter having the filter coefficient determined as the initial value. Then, the filter output image I (x, y) is output to the mask filter generation unit 602 (FIG. 19- (a1)).

The mask filter generator 602 outputs the filter output image I (x,
y) is evaluated by the evaluation function G (FIG. 19- (a2)). Specifically, based on the filtered image, the amount of high frequency components of the input image to be subjected to the digital watermark embedding process is determined, and the coefficient changing process of the mask filter is performed according to the amount of high frequency components.

In the configuration of FIG. 19, the filter output image I
High frequency component amount (edge amount (E)) included in (x, y)
Is determined, and when the edge amount (E) is smaller than the threshold (th) (E <th), a regenerated mask filter M (u, v) in which the coefficients of the mask filter are changed is generated, and the regenerated mask filter is generated. The filter is output to the filter processing unit 603, and the filter processing unit 603 applies the regenerated mask filter M (u, v) in which the coefficients of the mask filter are changed, and executes the filter processing again (FIG. 19- (a1)). I do. The processing result is output to the mask filter generation unit 602 again, evaluated by the evaluation function G, and it is determined whether E <th. This processing is repeatedly executed, and when E ≧ th, that is, when the number of edges greater than the threshold is detected, the filter output image I (x, y) from the filter processing unit 603 is converted to the digital watermark pattern generation unit 605. To generate a digital watermark pattern.

In the configuration of FIG. 19, mask filter generation section 602 applies the following equation as an evaluation function.
The output image passed through the filter processing unit 603 is represented by I (x,
y) and its evaluation function is G,

[0164]

[Equation 14]

It is assumed that As a result of the above equation, E = G (I
(X, y)) is compared with a threshold th, and when the high-frequency component amount (edge amount (E)) is smaller than the threshold value (th) (E <t
In h), a regenerated mask filter M (u, v) in which the coefficients of the mask filter are changed is generated, and the regenerated mask filter is output to the filter processing unit 603. When E ≧ th, that is, when an edge amount larger than the threshold value is detected, the filter output image I (x, y) from the filter processing unit 603 is converted to a digital watermark pattern generation unit 605.
To generate a digital watermark pattern.

The configuration shown in FIG. 19 is obtained by applying a step function, and the mask filter generation unit 602 generates the filter output image I input from the filter processing unit 603.
(X, y) is evaluated by an evaluation function G to which a step function is applied (FIG. 19- (b2)). Filter output image I
As a result of counting the number of edges (E) included in (x, y) and applying a step function, the edge amount (E) becomes a threshold (t)
h) If smaller than (E <th), a regenerated mask filter M (u, v) in which the coefficients of the mask filter are changed is generated, and the regenerated mask filter is filtered by the filter processing unit 6.
03, and the filter processing unit 603 outputs a regenerated mask filter M (u,
v) is applied and the filter processing is executed again (FIG. 19- (b)
1)) Yes. The processing result is returned to the mask filter generation unit 6 again.
02 and is evaluated by an evaluation function G to which a step function is applied, and it is determined whether E <th. This processing is repeatedly executed, and when E ≧ th, that is, when an edge amount larger than the threshold value is detected, the filter output image I (x, y) from the filter processing unit 603 is converted to a digital watermark pattern generation unit 605. To generate a digital watermark pattern.

As described above, in the digital watermark embedding processing apparatus of the present embodiment, the filter output image I (x, y) obtained as a result of performing the filter processing on the image to be subjected to the digital watermark embedding processing is evaluated. If the high-frequency component amount (edge amount (E)) included in the filter output image I (x, y) is equal to or less than a predetermined threshold, the regenerated mask filter M (u,
v) is generated and the filtering process is executed again,
On condition that the edge amount included in the filter output image I (x, y) obtained as a result of the filter processing has become larger than the threshold value, the filter output image I (x, y)
Since the digital watermark pattern generation processing is executed based on y), the digital watermark embedding amount can be maintained at a certain value or more.

As described above, the mask filter regenerating process in the mask filter generating unit 602 is performed on each of the divided areas of the original image 601 which is the image to be embedded with a digital watermark, and the mask for each area is masked. The filter may be generated. If the filter is regenerated for each area in this manner, an operation of embedding a large or a small amount of digital watermark only in a particularly low area becomes possible.

[Determination of Filter Coefficient by Analyzing Image Characteristics in Time Direction] Next, the filter characteristics are analyzed in the time direction of the input image to be subjected to the digital watermark embedding process. An embodiment of a digital watermark embedding processing device for changing coefficients will be described with reference to FIG. Here, the time refers to a time interval of every several frames or several fields, for example, when the input image has an image in the time direction such as a moving image.

The configuration of the digital watermark embedding processing apparatus shown in FIG. 20 will be described. The original image 701 is an image to be embedded with a digital watermark pattern, and includes various images such as an image read from a storage medium such as a hard disk or a DVD, or an image supplied from an image capturing device such as a scanner or a digital camera. It is.

The filter processing unit 704 includes the mask filter generated by the mask filter generation unit 703 based on the area characteristics of the area constituting the image of the original image 701 and the original image 70.
Perform a convolution operation with 1. The mask filter generation unit 703 receives an analysis value of a certain spatio-temporal region of an image sequence output from the moving image spatio-temporal analysis processing unit 702, and generates a mask filter having a filter coefficient determined based on the input value. . The filter processing unit 704 performs a convolution operation with the original image 701 using the mask filter generated by the mask filter generation unit 703.

The digital watermark pattern generation unit 706 stores the embedding information to be embedded in the image and the digital watermark pattern generation key (k) in the digital watermark pattern generation key (key) storage unit 705.
ey) to generate a digital watermark pattern based on The embedding information is various, such as, for example, copy control information, copyright information, and editing information, and is arbitrary information. The digital watermark pattern generation key (key) is, specifically, image division information when embedding a digital watermark pattern in an image, bit arrangement information, and the like, and is a process required to generate embedded information as a digital watermark pattern. Information.

The digital watermark pattern embedding unit 707 embeds the digital watermark pattern generated by the digital watermark pattern generation unit 706 in the original image 701 as input data. The image in which the digital watermark pattern is embedded is output as a digital watermark embedded image 708.

The digital watermark pattern generation section 706
Is a digital watermark pattern generation key (for example, a method of dividing the embedded information into small areas of the image shown in FIG. 7 and a method of assigning a small area corresponding to the bits of the embedded information shown in FIG. 8). key), the digital watermark pattern is generated, and the digital watermark pattern embedding unit 7 is executed.
07 embeds the digital watermark pattern in the image.

The mask filter generation processing in the mask filter generation unit 702 is performed on each of the divided areas of the original image 701 which is an image to be embedded with a digital watermark, to generate a mask filter for each area. It may be.

Processing for acquiring analysis values of a spatio-temporal region having an image sequence, which is executed in a moving image spatio-temporal analysis processing unit 702, a mask filter generation unit 703, and a filter processing unit 704, and a mask having filter coefficients based on the analysis values An example of a process of generating a filter will be described with reference to FIG.

When there is a certain image sequence such as a moving image, the moving image spatiotemporal analysis processing unit 702 performs a three-dimensional Fourier transform on it (FIG. 21-).
(1)). When the Fourier space is f (u, v, w), a function such as the following equation is defined with the frequency component w in the time axis as an axis.

[0178]

(Equation 15)

The value g (w) calculated based on the above equation can quantitatively represent the frequency component in the time direction (FIG. 21- (2)). Next, a threshold th is set on the w-axis of the function g (w), and an average value is calculated for frequencies higher and lower than the threshold th. High frequency average value is (ave_high),
Let the average value of the low frequency be (ave_low) (FIG. 21-
(3)).

When the high frequency average value (ave_high) is lower than the low frequency average value (ave_low), it is considered that the image has more temporally low frequency components.
When many digital watermarks are embedded in an image having many low-frequency components, there is a high possibility that the digital watermark pattern is recognized in a normal image observation state, depending on the shape of the embedded pattern.

Therefore, the moving image spatio-temporal analysis processing unit 702 compares the high-frequency average value (ave_high) and the low-frequency average value (ave_low) as the analysis value of the spatio-temporal area where the digital watermark embedding target image sequence exists. (Fig. 21-
(4)).

The mask filter generation unit 703 generates or selects and applies a 3 × 3 mask filter in a spatiotemporal region where the high frequency average value (ave_high) is lower than the low frequency average value (ave_low), and the filter processing unit 704, and the filter processing unit 704 performs edge detection by convolution of the original image 701 with the 3 × 3 mask filter generated by the mask filter generation unit 703 (FIG. 21-).
(5)) Then, the embedding amount of the digital watermark into the image is controlled to be small.

On the other hand, when it is determined that the high frequency average value (ave_high) is higher than the low frequency average value (ave_low) and that the region is a spatiotemporal region with a large amount of high frequency components, the mask filter generation unit 703 determines the 5 × 5 is generated or selected and applied to the filter processing unit 704 and output to the filter processing unit 704. The filter processing unit 704 performs a convolution operation between the 5 × 5 mask filter generated by the mask filter generation unit 703 and the original image 701, Execute edge detection (Fig. 21- (6))
Then, the embedding amount of the digital watermark into the image is controlled to be relatively large.

As described above, in the digital watermark embedding processing apparatus of the present embodiment, the high frequency component is obtained by analyzing the characteristics of the spatio-temporal region of the image to be subjected to the digital watermark embedding processing, for example, the frequency analysis of several frames or several fields of the moving image. A different mask filter is generated depending on whether the image has a large number of images or an image with a large number of low-frequency components, and edge detection processing is performed by convolution with the input image. Since it is configured to execute, digital watermark embedding processing according to the characteristics of the spatiotemporal region of the image, that is, a large amount of digital watermark is embedded in the spatiotemporal region with many high frequency components, and in the spatiotemporal region with many low frequency components Enables the processing of embedding a small amount of digital watermark. Write control becomes possible.

As described above, the mask filter generation processing in the mask filter generation unit 702 is performed on each of the divided areas of the original image 701 which is an image to be embedded with a digital watermark. May be generated. If the filter is regenerated for each area in this manner, an operation of embedding a large or a small number of digital watermarks only in an extremely low area becomes possible.

[System Configuration] A series of processes described in the above embodiment can be executed by hardware, software, or a composite configuration 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 a series of processes described above, specifically, a process of embedding a digital watermark is shown.

The system has a CPU (Central Processing).
Unit 1202). CPU (Central processing U
nit) 1202 is various application programs,
The OS (Operating System) is actually executed. ROM
A (Read-Only-Memory) 1203 stores a program executed by the CPU 1202 or fixed data as operation parameters. RAM (Random Access Memory)
Reference numeral 1204 denotes a program executed in the processing of the CPU 1202 and a storage area and a work area for parameters that change as appropriate in the program processing. CPU 1202, ROM 1203, RAM 120
4 and the hard disk 1205 are connected by a bus 1201 and can mutually transfer data. Further, data transfer with various input / output devices connected to the input / output interface 1211 is possible.

The keyboard 1212 and the mouse 1213 are C
The operation is performed by the user to input various commands to the PU 1202, the user is operated at the time of inputting command input data, and the like.
11 is input.

A drive 1209 is a floppy (registered trademark) disk, CD-ROM (Compact Disc Read Only M
emory), MO (Magneto optical) disk, DVD (Digi
tal Versatile Disc), a magnetic disk, a drive for recording and reproducing data on and from a removable recording medium 1210 such as a semiconductor memory. .

The CPU 1202 is provided with a keyboard 1212 and a mouse 213 via an input / output interface 1210.
When a command is input through the like, R
A program stored in an OM (Read Only Memory) 1203 is executed.

In the above-described embodiment, an image to be embedded with an electronic watermark or an image to be detected is an input device other than the camera 2071 connected to the input unit 1207, for example, a data input device such as a scanner, or a drive 1209. Floppy disk and CD-
ROM (Compact Disc Read Only Memory), MO (Magnet
o optical) Disc, DVD (Digital Versatile Dis)
c), can be input from a removable recording medium 1210 such as a magnetic disk or a semiconductor memory. This system has a configuration in which audio data can be input via the microphone 2072. Further, it is also possible to process data received via the communication unit 1208 as image data to be embedded with an electronic watermark or image data to be detected.

The CPU 1202 is not limited to the ROM storage program, but may be a program stored in the hard disk 1205, a program transferred from a satellite or a network, received by the communication unit 1208 and installed in the hard disk 1205, or a drive 1209.
It is also possible to load a program read from the removable recording medium 1210 installed in the hard disk 1205 and installed in the hard disk 1205 into a RAM (Random Access Memory) 1204 and execute the program.

In the system having the configuration shown in FIG. 22, the CPU 1202 performs processing according to each of the above-described embodiments or processing performed according to the above-described block diagrams and flowcharts. And the CPU 1202
Can output the processing result to an LCD (Liquid CrySta
lDisplay), a display device 2061 such as a CRT, and a speaker 2062 via an output unit 1206. Further, the processing data can be transmitted from the communication unit 1208, and can be stored in a recording medium such as the hard disk 1205.

An execution program for various processes is stored in a hard disk 120 as a recording medium built in the system.
5 or ROM 1203 in advance.
Alternatively, the program is a floppy disk, CD-R
OM (Compact Disc Read Only Memory), MO (Magneto
optical) disc, DVD (Digital Versatile Disc),
It can be temporarily or permanently stored (recorded) in a removable recording medium 1210 such as a magnetic disk or a semiconductor memory. Such a removable recording medium 1210 can be provided as so-called package software.

The program can be installed in the computer from the removable recording medium 1210 as described above, can be wirelessly transferred from a download site to the computer via a digital satellite broadcasting artificial satellite, or can be connected to a LAN (Local Area Network). ), Via a network such as the Internet, by wire to a computer, and the computer can receive the transferred program by the communication unit 1208 and install it on the built-in hard disk 1205.

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

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

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. In the embodiment, the image signal has been described as a target of the digital watermark embedding and detection processing. However, the configuration of the present invention is not limited to the image signal. Applicable to all signals. That is, the present invention has been disclosed by way of example, and should not be construed as limiting. For example, if it is audio data,
(A) frequency characteristics of the input audio signal of the audio, (b) arbitrary frequency domain information of the audio signal, (c) output from the filter processing unit, or (d) frequency characteristic analysis of the audio in the time direction. By determining the coefficients of the filter, generating a mask filter with the determined coefficients set, and filtering the original audio signal based on the generated mask filter, the embedding position of the digital watermark,
The amount of embedding can be set. 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.

[0200]

According to the configuration of the present invention described above, various effects described below can be obtained. First, according to the electronic watermark embedding processing apparatus and the electronic watermark embedding processing method of the present invention, (a) the characteristics of the entire image of the original image to be subjected to the electronic watermark embedding processing, and (b) an arbitrary area in the original image Information, (c) output from the filter processing unit, or (d) analyzing the characteristics of the image in the time direction to determine filter coefficients, and generating a mask filter in which the determined coefficients are set and generating The embedding position of the digital watermark and the amount of embedding are set by executing a convolution operation between the mask filter and the original image, so that the digital watermark is hardly recognized in a normal observation state and has a sufficient detection strength. Can be controlled.

Further, according to the digital watermark embedding processing apparatus and the digital watermark embedding processing method of the present invention, it is determined whether the image to be subjected to the digital watermark embedding processing is an image having a large number of high frequency components based on the frequency analysis of the image. A different mask filter is generated depending on whether the image has many low-frequency components, edge detection processing is performed by convolution with the input image, and digital watermark embedding processing is performed on the detected part. So
A digital watermark embedding process corresponding to an image, that is, a process of embedding a large amount of digital watermark in an image having many high-frequency components and embedding a small amount of digital watermark in an image having many low-frequency components becomes possible. Digital watermark embedding control corresponding to the watermark recognition level becomes possible.

Furthermore, according to the digital watermark embedding processing apparatus and the digital watermark embedding processing method of the present invention, the area characteristic of the image to be subjected to the digital watermark embedding processing, for example, whether it is the central part or the peripheral part of the image. A different mask filter is generated according to the configuration, the edge detection process is performed by a convolution operation with the input image, and the watermark is embedded in the detected portion. Embedding processing, for example, a process of embedding a large amount of digital watermark in the periphery of an image and embedding a small amount of digital watermark in the center of the image, is possible. It becomes possible.

Furthermore, according to the digital watermark embedding processing apparatus and the digital watermark embedding processing method of the present invention, the area characteristic of the image to be subjected to the digital watermark embedding processing, for example, whether it is the central part or the peripheral part of the image. Therefore, the digital watermark embedding process according to the image area is performed, for example, by performing the integration with the digital watermark pattern generation information by changing the different scaling parameter λ to generate the digital watermark pattern. In this case, a process of embedding a large amount of digital watermark and embedding a small amount of digital watermark in the center of the image can be performed, and digital watermark embedding control corresponding to visual perception of digital watermark can be performed.

Further, according to the digital watermark embedding processing apparatus and the digital watermark embedding processing method of the present invention, the filter output image I obtained as a result of performing the filter processing on the image to be subjected to the digital watermark embedding processing is obtained.
(X, y) is evaluated, and the filter output image I (x, y) is evaluated.
If the high-frequency component amount (edge amount (E)) included in y) is equal to or smaller than a predetermined threshold, a regenerated mask filter M (u, v) in which the coefficients of the mask filter are changed is generated and the filtering process is performed again. And the filter output image I (x, y) is provided on condition that the edge amount included in the filter output image I (x, y) obtained as a result of the filter processing is larger than a threshold value. Since the digital watermark pattern generation process is performed based on the
The digital watermark embedding amount can be maintained at a certain value or more.

Furthermore, according to the digital watermark embedding processing apparatus and the digital watermark embedding processing method of the present invention, the characteristics of the spatio-temporal region of the image to be subjected to the digital watermark embedding processing, for example, for each several frames or several fields of a moving image According to the frequency analysis, a different mask filter is generated depending on whether the image has a lot of high frequency components or an image with a lot of low frequency components, and the edge detection process is performed by a convolution operation with the input image. Since the digital watermark embedding process is executed, the digital watermark embedding process according to the characteristics of the spatiotemporal region of the image, that is, a large amount of digital watermark is embedded in the spatiotemporal region with many high frequency components, and the low frequency component It is possible to embed a small amount of digital watermark in the spatio-temporal area with many Electronic watermark embedding control corresponding to the knowledge level is possible.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a relative frequency distribution of an inner product value of an original image and a digital watermark pattern, and an inner product value of a digital watermark embedded image and a digital watermark pattern.

FIG. 2 is a diagram illustrating a criterion for determining the presence or absence of a digital watermark.

FIG. 3 is a diagram illustrating a threshold (th) applied to detection of a digital watermark.

FIG. 4 is a diagram illustrating a threshold value (th) for minimizing an electronic watermark embedding amount.

FIG. 5 is a diagram illustrating a threshold (th) when the probabilities P _FP and P _FN are small.

FIG. 6 is a diagram illustrating a process of embedding a plurality of digital watermark patterns in an image.

FIG. 7 is a diagram illustrating division of an original image into small areas.

FIG. 8 is a diagram illustrating the assignment of the same information bit to a plurality of small areas.

FIG. 9 is a diagram illustrating processing of a digital watermark pattern embedding processing apparatus.

FIG. 10 is a diagram illustrating a process of the digital watermark detection device.

FIG. 11 is a diagram illustrating digital watermark embedding and detection processing including digital watermark mask filter generation processing.

FIG. 12 is a diagram illustrating a configuration example of a digital watermark embedding processing device according to the present invention.

FIG. 13 is a processing flowchart for digital watermark embedding processing of the present invention.

FIG. 14 is a diagram illustrating an example of the configuration of a digital watermark embedding processing apparatus that executes generation of a mask filter based on image characteristics according to the present invention.

FIG. 15 is a diagram illustrating a mask filter generation process based on image characteristics according to the present invention.

FIG. 16 is a diagram illustrating an example of a configuration of a digital watermark embedding processing device that executes generation of a mask filter based on image characteristics of each region according to the present invention.

FIG. 17 is a diagram illustrating a mask filter generation process based on the image characteristics of each region according to the present invention.

FIG. 18 is a diagram illustrating an example of a configuration of a digital watermark embedding processing apparatus that executes generation of a mask filter based on a filter output image according to the present invention.

FIG. 19 is a diagram illustrating a mask filter generation process based on a filter output image according to the present invention.

FIG. 20 is a diagram illustrating an example of the configuration of a digital watermark embedding processing apparatus that performs generation of a mask filter based on the result of moving image spatiotemporal analysis according to the present invention.

FIG. 21 is a diagram illustrating a mask filter generation process based on the result of moving image spatio-temporal analysis according to the present invention.

FIG. 22 is a diagram illustrating an example of a system configuration that executes a digital watermark embedding process.

[Explanation of symbols]

 Reference Signs List 101 Image signal 102 Digital watermark pattern 103 Edge detection filter 104 Integrator 105 Adder 106 Digital watermark embedded image signal 107 Digital watermark detection target image 108 Digital watermark pattern 109 Inner product calculator 110 Comparison means 201 Original image 202 Mask filter generator 203 Filter processing unit 204 Digital watermark pattern generation key storage unit 205 Digital watermark pattern generation unit 206 Embedding information 207 Digital watermark pattern embedding unit 208 Digital watermark embedded image 401 Original image 402 Image characteristic detection unit 403 Mask filter generation unit 404 Filter processing unit 405 Electronics Watermark pattern generation key storage unit 406 Digital watermark pattern generation unit 407 Digital watermark pattern embedding unit 408 Digital watermark embedded image 501 Original image 50 Image area information detection unit 503 Mask filter generation unit 504 Filter processing unit 505 Digital watermark pattern generation key storage unit 506 Digital watermark pattern generation unit 507 Digital watermark pattern embedding unit 508 Digital watermark embedded image 601 Original image 602 Mask filter generation unit 603 Filter processing Unit 604 electronic watermark pattern generation key storage unit 605 electronic watermark pattern generation unit 606 electronic watermark pattern embedding unit 607 electronic watermark embedded image 701 original image 702 moving image spatio-temporal analysis processing unit 703 mask filter generation unit 704 filter processing unit 705 electronic watermark pattern Generation key storage unit 706 Digital watermark pattern generation unit 707 Digital watermark pattern embedding unit 708 Digital watermark embedded image 901 Original image 902 Embedded information 90 Digital watermark pattern generation key storage unit 904 Digital watermark pattern generation unit 905 Digital watermark pattern embedding unit 906 Digital watermark embedded image 1001 Digital watermark detection target image 1002 Digital watermark pattern generation key storage unit 1003 Digital watermark pattern generation unit 1004 Detection unit 1005 Detection information 1202 CPU 1203 ROM 1204 RAM 1205 Hard disk 1206 Output unit 1207 Input unit 1208 Communication unit 1209 Drive 1210 Removable full recording medium 1211 Keyboard / Mouse controller 1212 Keyboard 1213 Mouse 2061 Display device 2062 Speaker 2071 Camera 2072 Microphone

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuki Matsumura 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Osamu Nakamura 6-35-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F term (reference) 5B057 CA08 CA12 CA16 CB08 CB12 CB16 CE06 CE08 CG05 CG07 CH09 DA08 DB02 DB09 DC16 5C063 AA01 AB03 AB05 AC01 AC05 AC10 CA23 CA36 DA03 DA07 DA13 DB09 5C076 AA14 BA06 CA10 5J104 AA14

Claims (23)

[Claims] 1. A digital watermark embedding processing device for executing a digital watermark pattern embedding process, comprising: a mask filter generating means for generating a mask filter for a filtering process on a digital watermark embedding target signal; Filter processing means for performing a filtering process on the digital watermark embedding target signal using the mask filter thus obtained; digital watermark pattern generation means for generating a digital watermark pattern based on an output of the filter processing means; Means for embedding the digital watermark pattern generated by the means in the digital watermark embedding target signal, wherein the mask filter generating means obtains the digital watermark pattern based on the digital watermark embedding target signal. Electronic watermark embedding processing apparatus characterized by having a configuration to be output to the filtering means to generate different masks filter based on that analysis data. 2. The method according to claim 1, wherein the mask filter generating means includes: (a) an overall characteristic, or (b) a partial characteristic, or (c) an output value from the filter processing unit, or (d) a time of the digital watermark embedding target signal. 2. The electronic watermark embedding processing apparatus according to claim 1, wherein a different mask filter is generated based on at least one of the analysis results of the characteristics in the direction and output to the filter processing unit. 3. The image processing apparatus according to claim 1, wherein the mask filter generating means includes: (a) a characteristic of an entire image; (b) a characteristic of a partial region of the image; And (d) generating a different mask filter based on an analysis result of at least one of the temporal characteristics of the moving image and outputting the generated mask filter to the filter processing unit. 2. The digital watermark embedding processing device according to 1. 4. The digital watermark embedding processing device further performs a frequency analysis of the image to be subjected to the digital watermark embedding processing, and determines whether the image is an image having many high frequency components or an image having many low frequency components. The digital watermark embedding process according to claim 1, further comprising an image characteristic detecting unit, wherein the mask filter generating unit generates a different mask filter based on a detection result of the image characteristic detecting unit. apparatus. 5. The digital watermark embedding processing apparatus further comprises image area information detecting means for obtaining area division information of an image to be subjected to digital watermark embedding processing, wherein the mask filter generating means comprises: 2. The digital watermark embedding processing apparatus according to claim 1, further comprising a configuration for generating a different mask filter based on a detection result of the detection unit. 6. The image area information detecting means obtains area division information in which a central area and a peripheral area of an image are divided in a stepwise manner. The mask filter generating means detects the image area information detecting means. Based on the stepwise segmentation information obtained as a result, the configuration is such that different mask filters are generated in such a manner that the embedding amount of the digital watermark is set to be small in the central region of the image and large in the peripheral region of the image. The digital watermark embedding processing device according to claim 5. 7. The digital watermark embedding processing apparatus further comprises image area information detecting means for acquiring area division information of an image to be subjected to digital watermark embedding processing, wherein the digital watermark pattern generating means comprises: A configuration in which a different scaling parameter λ is applied based on a detection result of the information detecting means, and an output result of the filter processing means is integrated with the digital watermark pattern generation information to generate a digital watermark pattern. 2. The digital watermark embedding processing device according to claim 1, wherein: 8. The mask filter generating means, wherein the filter processing means evaluates a filter output image I (x, y) obtained as a result of the filter processing, and outputs the filter output image I (x, y). If the amount of high-frequency components included in is equal to or less than a predetermined threshold, a regenerated mask filter in which the coefficients of the mask filter are changed is generated and output to the filter processing unit. A filtering process is performed by applying a filter, and on the condition that an edge amount included in the filter output image I (x, y) becomes larger than a threshold value, a digital watermark is generated based on the filter output image I (x, y). 2. A configuration for executing a pattern generation process.
3. A digital watermark embedding processing device according to claim 1. 9. The digital watermark embedding processing apparatus further includes a spatio-temporal analysis processing means for analyzing a spatio-temporal region characteristic of an image to be subjected to the digital watermark embedding processing, and the mask filter generating means includes: 2. The digital watermark embedding processing apparatus according to claim 1, further comprising a configuration for generating different mask filters based on an analysis result of the analysis processing means. 10. The spatio-temporal analysis processing means executes frequency component analysis included in the moving image by performing frequency analysis over a plurality of frames of the moving image to be subjected to digital watermark embedding processing, and the mask filter generating means 10. The digital watermark embedding process according to claim 9, wherein a different mask filter is generated according to frequency component information of a plurality of frames of a moving image acquired as an analysis result of the spatio-temporal analysis processing unit. apparatus. 11. The apparatus according to claim 1, wherein said mask filter generation means generates a different mask filter for each small area based on analysis data obtained based on information for each small area of the digital watermark embedding target signal. 2. The digital watermark embedding processing device according to claim 1, wherein 12. A digital watermark embedding processing method for executing a digital watermark pattern embedding process, wherein the mask filter generating step generates a mask filter for filtering a digital watermark embedding target signal; A filtering processing step of performing a filtering process on the digital watermark embedding target signal using the mask filter obtained above, a digital watermark pattern generating step of generating a digital watermark pattern based on an output of the filtering process step, A digital watermark pattern embedding step of performing a process of embedding the digital watermark pattern generated in the step in the digital watermark embedding target signal, wherein the mask filter generating step The electronic watermark embedding processing method characterized by performing the step of outputting the filtering means to generate a different mask filters based on the analysis data obtained based on the electronic watermark embedding target signal. 13. The mask filter generating step includes: (a) an overall characteristic or (b) a partial characteristic of the digital watermark embedding processing target signal, or (c) an output value from the filter processing unit, or (d) a time. 13. The digital watermark embedding method according to claim 12, wherein different mask filters are generated based on at least one analysis result of the characteristics in the direction. 14. The mask filter generating step, when the digital watermark embedding processing target signal is an image, comprises: (a) overall image characteristics, (b) partial region characteristics of the image, or (c) the filter processing unit. 13. The digital watermark embedding processing method according to claim 12, wherein different mask filters are generated based on at least one of the output values from (i) and (d) an analysis result of the characteristics in the time direction of the moving image. 15. The digital watermark embedding method further performs a frequency analysis of the image to be subjected to the digital watermark embedding processing, and determines whether the image has a high frequency component or a low frequency component. The digital watermark embedding method according to claim 12, further comprising an image characteristic detecting step, wherein the mask filter generating step generates a different mask filter based on a detection result in the image characteristic detecting step. 16. The digital watermark embedding processing method further includes an image area information detecting step of obtaining area division information of an image to be subjected to digital watermark embedding processing, wherein the mask filter generating step includes: 13. The digital watermark embedding method according to claim 12, wherein different mask filters are generated based on a detection result of the detection step. 17. The image area information detecting step acquires area division information in which a central area and a peripheral area of an image are divided in a stepwise manner. The mask filter generating step includes a step of detecting the image area information detecting step. A different mask filter is generated based on the stepwise segmentation information obtained as a result, in which the embedding amount of the digital watermark is set to be small in the central region of the image and large in the peripheral region of the image. 16. The digital watermark embedding processing method according to item 16. 18. The digital watermark embedding processing method further includes an image area information detecting step of acquiring area division information of an image to be subjected to the digital watermark embedding processing, wherein the digital watermark pattern generating step includes: Applying a different scaling parameter λ based on the detection result of the information detection step, and integrating the output result of the filter processing means and the digital watermark pattern generation information to generate a digital watermark pattern. The digital watermark embedding processing method according to claim 12. 19. The mask filter generating step includes the step of: in the filtering step, evaluating a filter output image I (x, y) obtained as a result of performing the filter processing; If the amount of high-frequency components included in is equal to or less than a predetermined threshold, a regenerated mask filter in which the coefficients of the mask filter are changed is generated and output to the filter processing unit. A filtering process is performed by applying a filter, and on the condition that an edge amount included in the filter output image I (x, y) becomes larger than a threshold value, a digital watermark is generated based on the filter output image I (x, y). 13. The digital watermark embedding processing method according to claim 12, wherein a pattern generation processing is performed. 20. The digital watermark embedding method further includes a spatio-temporal analysis processing step of analyzing a spatio-temporal region characteristic of an image to be subjected to the digital watermark embedding processing, and the mask filter generating step includes: 2. A different mask filter is generated based on an analysis result of the analysis processing step.
3. The digital watermark embedding processing method according to 2. 21. The spatio-temporal analysis processing step performs a frequency component analysis included in the moving image by performing frequency analysis over a plurality of frames of the moving image to be subjected to the digital watermark embedding processing. 21. A different mask filter according to frequency component information of a plurality of frames of a moving image acquired as an analysis result of the spatiotemporal analysis processing step.
2. A digital watermark embedding processing method according to (1). 22. The mask filter generating step, wherein a different mask filter is generated for each small area based on analysis data obtained based on information for each small area of a digital watermark embedding target signal. Item 13. A digital watermark embedding method according to item 12. 23. A program for executing a digital watermark pattern embedding process on a computer system, comprising: a mask filter generating step for generating a mask filter for filtering a digital watermark embedding target signal; and the mask filter generating step. A filtering process step of performing a filtering process on the digital watermark embedding target signal using the mask filter generated in the above, a digital watermark pattern generating step of generating a digital watermark pattern based on an output in the filtering process step, Embedding a digital watermark pattern generated in the pattern generating step into the digital watermark embedding target signal. Data generation step, the program characterized by comprising the step of performing the step of outputting the filtering means to generate a different mask filters based on the analysis data obtained based on the electronic watermark embedding target signal.