JP2004320672A - Electronic watermark embedding method, electronic watermark detecting method, electronic watermark embedding apparatus, and electronic watermark detecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic watermark embedding method and apparatus, and electronic watermark detecting method and apparatus in which an electronic watermark can be surely detected. <P>SOLUTION: Input image data are developed into a plurality of bit planes from MSB to LSB, a first encoding path is generated for each bit plane, arithmetic encoding is performed according to the first encoding path, an arithmetic encoding quantity is controlled from a target code amount, an arithmetic code break-off point is determined, and the resultant arithmetic code break-off point is changed into a bit plane boundary. Signature data are generated from the input image data, the signature data are embedded in the input image data, the image data with the signature data embedded therein are developed into a plurality of bit planes, a second encoding path similar to the first encoding path is generated for each bit plane, and arithmetic encoding is performed according to the second encoding path to the arithmetic code break-off point, thereby generating encoded data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a digital watermark embedding method, a digital watermark detecting method, a digital watermark embedding device, and a digital watermark detecting device used for detecting falsification of image data.
[0002]
[Prior art]
<< First prior art >>
[Fragile digital watermarking technology]
FIG. 31 is an explanatory diagram of the concept of a bit-plane. FIG. 31 illustrates four vertical and three horizontal coefficients. Each coefficient is represented by a sign bit and an absolute value. As shown in FIG. 31, in the bit plane, the absolute value (“1”) corresponding to each sample obtained by sequentially slicing the coefficient with each bit from the MSB (most significant bit) to the LSB (least significant bit). Or, there is a bit plane of "0") and a bit plane of a coefficient sign ("+" or "-").
[0003]
FIG. 32 is an explanatory diagram of an operation of embedding a fragile digital watermark in a bitmap image. As shown in FIG. 32, at the time of embedding a digital watermark, a hash value is obtained from a bit plane other than the LSB (for strict verification, a bit plane other than the LSB and all bits not used for embedding the LSB). The calculated hash value (digital signature) encrypted by the public key cryptosystem is embedded in the LSB. Normally, the embedding position in the LSB is randomized using a pseudo-random sequence using a key as a seed.
[0004]
FIG. 33 is an explanatory diagram of an operation for verifying a fragile digital watermark. As shown in FIG. 33, at the time of verifying the digital watermark, the embedding position is determined from the LSB portion of the image in which the signature data is embedded by the same procedure as the embedding side, and the embedded data is extracted. The hash value generated at the time of embedding the digital watermark is decrypted from the extracted data. In addition, a hash value is calculated from a bit plane other than the LSB (in the case of strict verification, a bit plane other than the LSB and all the bits not used for embedding the LSB) by the same algorithm as the embedding side, and Is compared with the decrypted hash value. As a result of the comparison, if both hash values match, it is known that the image has not been tampered with (for example, see Patent Document 1).
[0005]
Normally, the bit length of a hash value generated compared to image data is very short. For example, in the case of a hash algorithm known as SHA1, the output data is 160 bits regardless of the input data length. However, due to the characteristics of the hash calculation, even if there is only a slight change in the image, the generated hash value becomes a completely different value. Therefore, by comparing the hash values, it is possible to detect even falsification of one pixel. Further, if the range in which one hash value is calculated is not the entire image but a range divided by M × N pixel size blocks in the image, it is possible to detect tampering of the image in units of M × N blocks. In addition, a tampered portion in an image can be specified in block units.
[0006]
There is also a method of embedding a hash value or signature data in a coefficient on a frequency space after wavelet (Wavelet) transform, DCT (discrete cosine transform), quantization, or the like. This method is also similar to the case of digital watermarking for a bitmap, except that the hash value calculation target and the signature data embedding target are simply replaced by the coefficients after frequency conversion from the image data itself. Furthermore, there is a method of changing the coordinates of the hash value calculation target and the embedding target, and the same detection method is used in this method.
[0007]
[Coding method of coefficients in frequency space]
When embedding an electronic watermark in a coefficient in the frequency space after wavelet transform, DCT, quantization, or the like, the coefficient may be encoded (compressed) at the same time. FIG. 34 is a block diagram showing a configuration for encoding coefficients in the frequency space. As shown in FIG. 34, the configuration for encoding the coefficients includes a frequency conversion unit 1011 that performs frequency conversion on the input image, and a configuration in which the conversion coefficients are expanded on a bit plane from MSB to LSB to have a predetermined size. A bit plane encoding path generating unit 1012 for determining an encoding path (procedure for performing an encoding process) of each bit plane for each code block; an arithmetic encoding unit 1013 for performing arithmetic encoding according to the encoding path; And a rate control unit 1014 for controlling the code amount from the arithmetic code to a target code amount (equivalent to the compressed bit rate or file size).
[0008]
In one example of a coding method, a frequency conversion unit 1011 converts an image into bit planes of coefficients, and a bit plane coding pass generation unit 1012 generates one coding pass for one bit plane, and performs arithmetic coding. The coding means 1013 performs arithmetic coding according to the coding pass. FIG. 35 shows bit planes of bit plane numbers “n−2”, “n−3”,..., “1” and “0” (in FIG. 35, Bit-plane (n−2), Bit-plane (n -3),..., Bit-plane (1), Bit-plane (0)), one encoding pass (in FIG. 35, coding pass X) is generated. FIG. 4 is an explanatory diagram of an arithmetic encoding process in the case of Arithmetic coding of all bit planes is performed, and thereafter, the rate control unit 1014 controls the code amount. At that time, the rate control means 1014 counts the arithmetic coding amount for each coding pass, and when the target coding amount is reached, discards the arithmetic coding data after that. The position where the arithmetic code is discontinued in this way is called an "arithmetic code discontinuation point".
[0009]
In the above example, since the arithmetic code abort point is a boundary of any bit plane, only some coefficients of a certain bit plane are included in the compressed arithmetic code data, and some coefficients are truncated. , Is not included in the compressed arithmetic code data. Therefore, when embedding a digital watermark, embed the digital watermark in a predetermined bit plane, and if there is an arithmetic code breakpoint after that bit plane, decode all data in that bit plane during verification. So that all digital watermarks can be extracted. The same applies to the case where the censoring point is different for each code block which is a unit in which arithmetic coding is performed.
[0010]
However, for example, in JPEG2000, which is a next-generation still image coding standard, one bit plane is composed of three types of coding passes, and then arithmetic coding is performed according to each coding pass. Specifically, each bit plane of the frequency-transformed (in this case, wavelet transformed) coefficient is converted into a significance propagation pass, a magnitude refinement pass, and a cleanup pass. arithmetic coding using three types of coding passes called “pass”. It should be noted that the coding pass in which each bit of the bit plane is coded differs depending on the status of the already coded upper bit plane including peripheral pixels.
[0011]
In JPEG2000, the number of the bit plane from the MSB side where “1” first appears is separately encoded, and the bit plane where “1” first appears is encoded only by the cleanup pass. FIG. 36 shows an encoding path generated by the above processing. In FIG. 36, the coding path and the arithmetic code break point of a certain code block are shown, but they usually differ for each code block. As shown in FIG. 36, each bit plane (in FIG. 36, Bit-plane (n-2), Bit-plane (n-3), Bit-plane (n-4),..., Bit-plane (0 ) Are subjected to arithmetic coding according to a plurality of coding paths (in FIG. 36, denoted as Coding Pass A, Coding Pass B, and Coding Pass C), and thereafter, the rate control unit 1014 performs coding. Control the volume. At that time, the rate control means 1014 counts the arithmetic coding amount of the coding path, and when the target coding amount is reached, discards the arithmetic coding data thereafter.
[0012]
<< 2nd prior art >>
[Digital watermark embedding method when bit plane is censored]
As described above, when embedding an electronic watermark while compressing the transform coefficient obtained by frequency-converting image data, compression is performed by cutting off the bit plane of the transform coefficient for each code block having a predetermined size. May be. In such a case, a digital watermark is embedded in a bit plane immediately before the censored bit plane in order to make the entire image data subject to tampering detection. More specifically, as shown in FIG. 37, when a bit plane of bit plane number “2” or less is cut off in a certain code block, a digital watermark is embedded in the bit plane of bit plane number “3”.
[0013]
In this way, when verification is performed during the decoding process, the bit plane number “2” is aborted and does not exist, so that the least significant bit plane (bit plane number “3”) of the decoded bit planes is electronically assigned. It can be seen that the watermark is embedded. Therefore, a digital watermark can be extracted from the bit plane.
[0014]
<< 3rd prior art >>
The third related art is the same as the first related art.
[0015]
[Patent Document]
JP 2001-042768 A (FIGS. 1 to 4)
[0016]
[Problems to be solved by the invention]
<< Issues of the first prior art >>
In the first conventional technique, when one bit plane is arithmetically encoded using a plurality of encoding passes, there is a possibility that the arithmetic code after the encoding pass in the middle of the bit plane may be discontinued. For example, as shown in FIG. 36, when the arithmetic code of the encoding path after the arithmetic code break point is truncated, the bit plane of bit plane number n-4 (in FIG. 36, Bit-plane (n-4 ) Will be encoded only partially.
[0017]
Therefore, when embedding a digital watermark, even if the digital watermark is embedded in a predetermined bit plane, the arithmetic code is truncated in the middle of the encoding pass encoding the bit plane, and the arithmetic code thereafter It is possible that truncated data is truncated. In this case, some of the coefficients in which the digital watermark is embedded are truncated and are not included in the compressed arithmetic code data. As a result, all of the embedded digital watermarks cannot be taken out (in the case of fragile digital watermarking, if there is no tampering, the same digital watermark as in the case of embedding must be extracted in verification). There is a problem that verification cannot be performed correctly.
[0018]
<< Issues of the Second Prior Art >>
In the second conventional technique, once decoding is performed from a state in which a digital watermark is embedded in a compressed state, information as to which bit plane the transform coefficient has been aborted is lost. There is a problem that it cannot be determined.
[0019]
When a frequency conversion such as a JPEG2000 reversible filter is used, if the image once decoded is subjected to the same frequency conversion again to obtain a conversion coefficient, the same conversion coefficient can be obtained. Therefore, as shown in FIG. 38 (a), the bit planes that are truncated at the time of decoding (in FIG. 38 (a), bit plane numbers '2', '1', and '0') are all set to "0". , All the truncated bit planes become “0” by performing the same reversible frequency conversion again. Therefore, by examining the bits of each bit plane from the LSB, the bit plane in which “1” first appears can be determined as the bit plane in which the digital watermark is embedded. However, also in this case, by embedding the digital watermark, at least one bit of “1” must be present in the bits of the bit plane in which the digital watermark is embedded.
[0020]
However, as shown in FIG. 38B, at the time of decoding, the most significant bit plane of the truncated bit plane (the bit plane number “2” in FIG. 38B) has a non-zero coefficient. In this case, since the data is usually decoded as “1”, the above means cannot be used. The reason why such processing is performed is that when dequantizing a quantized value, it is considered that the best image quality is obtained by reconstructing the value by adding a value that is half the quantization step size. It is mentioned. Aborting a bit plane below a certain bit plane number is equivalent to quantizing with a quantization step size of “2 (the bit plane number)”. Therefore, adding half of the step size is equivalent to decoding with the most significant bit plane of the bit plane just censored being “1”. However, what to do with the values of the other lower bitplanes that have been censored is left to the discretion of the decoding, and if decoding and frequency conversion are performed again, can not predict.
[0021]
<< The problem of the third prior art >>
In the third conventional technique, there is a problem that the image quality is significantly deteriorated depending on the location where the information bit of the digital watermark is embedded.
[0022]
Further, when selecting a coefficient for embedding the information bit of the digital watermark, there is a case where the grouping is performed by a group of nearby coefficients and the information bit is embedded in the group. However, when there is no portion suitable for embedding information (for example, a region of a high frequency component such as a hair shown in FIG. 39) in the grouping, a portion not suitable for embedding information (for example, shown in FIG. 39). Information must be embedded in a low-frequency component region such as a uniform background), and there is a problem that the image quality deteriorates on a flat background or the like. Also, when the SNR scalability of JPEG2000 is used, information is embedded in the bit plane on the MSB side rather than the LSB, so that it is more easily perceived by humans.
[0023]
<< Object of the first invention >>
A first invention is to solve the problem of the first related art, and an object of the invention is to provide a digital watermark embedding method and a digital watermark embedding device that can reliably detect a digital watermark. is there.
[0024]
<< Object of the second invention >>
A second invention is to solve the problem of the second prior art, and an object of the invention is to provide a digital watermark embedding method and a digital watermark detection method for reliably specifying a bit plane in which a digital watermark is embedded. A method, a digital watermark embedding device, and a digital watermark detection device are provided.
[0025]
<< Object of the third invention >>
A third invention is to solve the problem of the third prior art, and an object of the invention is to provide a digital watermark embedding method, a digital watermark detection method, and a digital watermark embedding method that can suppress deterioration of image quality due to digital watermark embedding. An object of the present invention is to provide a digital watermark embedding device and a digital watermark detecting device.
[0026]
Another object of the third invention is to provide a digital watermark embedding method, a digital watermark detection method, and a digital watermark embedding device that can suppress a decrease in compression efficiency by using a compression characteristic when selecting an embedding coefficient. , And a digital watermark detection device.
[0027]
Still another object of the third invention is to provide a digital watermark embedding method, a digital watermark detecting method, a digital watermark embedding device, and a digital watermark detecting device that can increase the capacity of embedding a message.
[0028]
[Means for Solving the Problems]
One aspect of the digital watermark embedding method of the first invention is a digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side, wherein input image data is converted from a most significant bit to a least significant bit. Developing the data into a plurality of bit planes, generating one or more types of first encoding passes for each bit plane, and arithmetically encoding the data of each bit plane according to the first encoding pass. (1) controlling the arithmetic coding amount in the arithmetic coding based on a target code amount to determine an arithmetic code censoring point; and determining the obtained arithmetic code censoring point as a bit plane. Changing the obtained arithmetic code censoring point to a bit plane boundary if not at a boundary; and Generating signature data, embedding signature data in the input image data, developing the image data in which the signature data is embedded into a plurality of bit planes, and generating a second encoding pass for each bit plane. And a step of arithmetically encoding the data of each of the bit planes according to the second encoding pass up to the arithmetic code discontinuation point to generate second encoded data.
[0029]
One embodiment of the digital watermark embedding method of the second invention is a digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side, wherein ID information indicating a bit plane into which a digital watermark is embedded is stored. The method is characterized by including a step of embedding and a step of embedding data in a bit plane specified by the ID information. One embodiment of the digital watermark detection method of the second invention is a digital watermark detection method executed on image data by a configuration of a digital watermark verification side, wherein the digital watermark detection method is embedded in image data by the digital watermark embedding method. And extracting a bit plane in which the data is embedded, and extracting the data from the specified bit plane.
[0030]
An aspect of a digital watermark embedding method according to a third invention is a digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side, wherein a bit plane for embedding information in input image data is provided. Is specified, the data of the bit plane higher than the bit plane in which the information is embedded is evaluated, and a step of performing labeling indicating the order of the position where the information is embedded based on the evaluation result is performed. According to the order indicated by the labeling, Embedding embedded data in the input image data. One embodiment of the digital watermark detection method of the third invention is a digital watermark detection method executed on image data by a configuration of a digital watermark verification side, wherein data is embedded by the digital watermark embedding method. Receiving the image data, a bit plane for extracting information from the received image data is designated, and evaluates data of a bit plane higher than the designated bit plane, and based on the evaluation result, The method includes a step of performing labeling indicating an order of a position where information is embedded, and a step of extracting embedded data from the received image data according to the order indicated by the labeling.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
{1. First invention≫
{1-1. First Embodiment≫
[Configuration of digital watermark embedding side]
FIG. 1 is a block diagram illustrating a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the first embodiment.
[0032]
As shown in FIG. 1, the configuration of the digital watermark embedding side of the first embodiment includes a frequency conversion unit 1011 that performs frequency conversion on image data input through an input terminal 1001 and outputs a conversion coefficient, A conversion coefficient storage unit 1021 for storing the conversion coefficient output from the conversion unit 1011. Further, the configuration of the digital watermark embedding side according to the first embodiment includes a bit plane for generating an encoding path (procedure for performing an encoding process) for bit plane encoding the transform coefficient output from the frequency transform unit 1011. It has an encoding path generation unit 1012 and an arithmetic encoding unit 1013 that arithmetically encodes a transform coefficient according to each encoding path generated by the bit plane encoding path generation unit 1012. Further, the configuration of the digital watermark embedding side of the first embodiment is such that the code amount of the arithmetic code arithmetically coded by the arithmetic coding unit 1013 is equal to the code amount input from the target code amount input terminal 1003. It has a rate control means 1014 for controlling the code amount of the generated arithmetically coded data. Furthermore, the configuration on the digital watermark embedding side of the first embodiment is a coding path control unit that changes the arithmetic code cutoff point determined by the rate control unit 1014 so that all the embedded digital watermarks can be extracted. 1015.
[0033]
As shown in FIG. 1, the configuration of the digital watermark embedding side of the first embodiment includes a signature generation unit 1101 for generating signature data from the transform coefficient stored in the transform coefficient storage unit 1021, A signature embedding unit 1102 for embedding the signature data obtained from the unit 1101 into the transform coefficient, a bit plane encoding path generating unit 1012A for generating an encoding pass for bit plane encoding the transform coefficient in which the signature data is embedded, An arithmetic encoding unit 1013A that arithmetically encodes each encoding pass generated by the bit plane encoding pass generation unit 1012A and outputs compressed data after encoding / digital watermark embedding. The arithmetic coding unit 1013A performs arithmetic coding up to the coding pass changed by the coding pass control unit 1015 for each coding pass generated by the bit plane coding pass generation unit 1012A, and performs coding / digital watermarking. Get compressed data. The compressed data after the encoding / digital watermark embedding generated by the arithmetic encoding unit 1013A is output through an output terminal 1004 and passed to a configuration on the digital watermark verification side described below via a network or the like.
[0034]
[Configuration of Digital Watermark Verification Side]
FIG. 2 is a block diagram illustrating a configuration (digital watermark detection device) on the digital watermark verification side according to the first embodiment.
[0035]
As shown in FIG. 2, the configuration of the digital watermark verification side of the first embodiment receives compressed data output from the output terminal 1004 (FIG. 1) of the configuration of the digital watermark embedding side through an input terminal 1006. And decoding means 1031 for decoding the compressed data. The configuration of the digital watermark verification side according to the first embodiment includes a signature generation unit 1202 that generates signature data from the coefficient obtained by the decryption unit 1031, and a digital watermark embedding side based on the coefficient obtained by the decryption unit 1031. Signature extracting means 1201 for extracting the embedded signature data, signature comparing means 1203 for comparing the signature data extracted by the signature extracting means 1201 with the signature data generated by the signature generating means 1202, and outputting a comparison result; Having. The comparison result output from the signature comparison unit 1203 is output through the output terminal 1007.
[0036]
[Operation on the digital watermark embedding side]
As shown in FIG. 1, image data of a target image in which a digital watermark is to be embedded is input to an input terminal 1001. The frequency transform unit 1011 performs frequency transform such as wavelet transform or DCT on the image data input to the input terminal 1001, and generates coefficients in a frequency space. The conversion coefficient storage unit 1021 stores the conversion coefficient generated by the frequency conversion unit 1011.
[0037]
The bit plane coding path generation unit 1012 divides the transform coefficient generated by the frequency conversion unit 1011 into code blocks (Code-blocks) of a predetermined size, and generates a plurality of bits from MSB to LSB for each code block. After being developed into planes, a coding path for coding each bit plane is determined according to a predetermined rule. The arithmetic coding unit 1013 performs arithmetic coding for each coding pass generated by the bit plane coding pass generation unit 1012, and generates coded (compressed) data. When JPEG2000 which is a still image coding standard is applied, a wavelet transform is used for the frequency conversion, and each bit plane of the wavelet transform coefficient is divided into the above three types of coding paths (significance propagation path, magnitude refinement). Pass, cleanup pass).
[0038]
The rate control unit 1014 performs arithmetic coding for each coding pass obtained by the arithmetic coding unit 1013 for each code block so that the arithmetic coding amount becomes the target coding amount input from the input terminal 1003. The amount is counted, and when the target encoding amount is reached, the subsequent encoding passes are discarded. By this processing, the arithmetic code censoring point in each code block is determined, and the encoding path included in the compressed arithmetically encoded data is determined (see FIG. 3A described later).
[0039]
The encoding path control unit 1015 determines that the arithmetic code termination point obtained by the rate control unit 1014 is in the middle of a bit plane that does not include a part of the data of a certain bit plane (see FIG. )), And the arithmetic code abort point is changed to be on the boundary of the bit plane (see FIG. 3B described later). After that, in each code block, among the bit planes included in the compressed arithmetically encoded data, the bit plane closest to the LSB is set as the bit plane in which the signature data is embedded.
[0040]
FIGS. 3A and 3B are explanatory diagrams of an encoding path control method according to the first embodiment. FIG. 3A shows an encoding path of the bit plane before control by the encoding path control unit 1015, and FIG. 3B shows an encoding path of the bit plane after control by the encoding path control unit 1015. Show. In FIGS. 3A and 3B, each bit plane is configured by three coding passes (in the figure, coding pass A, coding pass B, and coding pass C).
[0041]
In the code block CB0 (denoted as Code-block 0 in FIG. 3), the rate control unit 1014, as shown in FIG. Arithmetic code truncation points are set so that up to a coding pass A (denoted as coding pass A in FIG. 3) in the middle of Bit-plane 0 is included in the compressed arithmetically coded data. are doing. Therefore, the coding path control unit 1015 changes the arithmetic code abort point so that the arithmetic code abort point is on the boundary of the bit plane, and as shown in FIG. The data up to the encoding pass C of the bit plane is included in the arithmetically encoded data after compression.
[0042]
Further, as shown in FIG. 3A, the rate control unit 1014 determines that the code block CB1 (denoted as Code-block 1 in FIG. 3) has a bit plane of bit plane number “1” (FIG. 3). In FIG. 3, the arithmetic code censoring point is set so that up to an encoding pass A (indicated as Coding pass A in FIG. 3) in the middle of Bit-plane 1 is included in the arithmetically encoded data after compression. Is set. Therefore, the arithmetic code abort point is changed by the encoding path control unit 1015 so that the arithmetic code abort point is on the boundary of the bit plane, and as shown in FIG. The arithmetic code censoring point is changed so that up to the coding pass C of the bit plane 2 ′ (denoted as Bit-plane 2 in FIG. 3) is included in the arithmetically coded data after compression. In this case, the arithmetic code termination point may be set at the bit plane boundary, and may include the same bit plane or may include up to the next higher bit plane.
[0043]
Further, as shown in FIG. 3A, the rate control unit 1014 determines whether the code block CB2 (denoted as Code-block 2 in FIG. 3) has a bit plane number “2” (FIG. 3). In FIG. 3, an arithmetic code break point is set so as to include a coding pass B (denoted as Coding pass B in FIG. 3) in the middle of Bit-plane 2. Therefore, the arithmetic code abort point is changed by the encoding path control unit 1015 so that the arithmetic code abort point is on the boundary of the bit plane, and the compressed arithmetic code C up to the encoding path C of the same bit plane '2' is changed. Change the arithmetic code truncation point to be included in the data.
[0044]
In the code block CB3 (denoted as Code-block 3 in FIG. 3), as shown in FIG. 3A, the arithmetic code break point is on the bit plane boundary, so that it is not necessary to change this.
[0045]
By the above processing, the state of the encoding path included in the compressed arithmetic code data in each code block after the encoding path control is as shown in FIG. The bit plane in which the signature data is embedded is the bit plane closest to the LSB side among the bit planes included in the arithmetically encoded data after compression in each code block. Therefore, in the case of FIG. 3B, the bit plane numbers included in the compressed arithmetically coded data are “0”, “2”, and “0” for each of the code blocks CB0, CB1, CB2, and CB3. 2 'and' 1 '.
[0046]
FIGS. 3A and 3B show a case where each bit plane is divided into three types of encoding passes. However, the same processing is performed when each bit plane is constituted by more types of encoding passes. can do. Further, when changing the arithmetic code censoring point to the bit plane boundary, the bit plane boundary may be selected so that the difference between the arithmetic coding amount before the change and the arithmetic coding amount after the change is minimized. Good.
[0047]
The signature generation unit 1101 generates signature data for the transform coefficient stored in the transform coefficient storage unit 1021. The signature data is obtained from the conversion coefficients excluding the coefficients for embedding the generated signature data among the conversion coefficients. Specifically, (1) data of bit planes other than the bit plane in which the signature data is embedded (this is obtained by the encoding path control unit 1015); and (2) the signature data of the bit plane in which the signature data is embedded. Using all bits not used for embedding, a hash value obtained by a hash function such as SHA1, a hash value encrypted by an encryption algorithm such as RSA, a part of the hash value, or the like is used as signature data. .
[0048]
The signature embedding unit 1102 embeds the signature data obtained from the signature generation unit 1101 into the conversion coefficient stored in the conversion coefficient storage unit 1021. The embedding position may be a pseudo-random sequence or a position scrambled by a replacement table.
[0049]
The bit plane encoding path generation unit 1012A performs the same processing as that performed by the bit plane encoding path generation unit 1012 on the transform coefficient in which the signature data obtained by the signature embedding unit 1102 is embedded. That is, the transform coefficient in which the signature data is embedded is divided into code blocks of a predetermined size, and each code block is developed into a plurality of bit planes from the MSB to the LSB. For this purpose, the encoding path is determined according to a predetermined rule. The arithmetic coding unit 1013A performs arithmetic coding up to the coding path changed by the coding path control unit 1015 for each coding pass generated by the bit plane coding pass generation unit 1012A, and encodes (compresses) the encoded data. Get. The coefficient in which the signature data is embedded and encoded is output through an output terminal 1004.
[0050]
[Operation on the digital watermark verification side]
As shown in FIG. 2, compressed image data for verifying a digital watermark is input to an input terminal 1006. The compressed image data input to the input terminal 1006 is passed to the decoding unit 1031. The decoding unit 1031 decodes the arithmetically coded data and generates a transform coefficient in the frequency space.
[0051]
The signature extracting unit 1201 extracts signature data embedded in a transform coefficient. The extraction is performed by determining an embedding position by the same method as that at the time of embedding the signature data, and extracting data from the embedding position. If the hash value or the like is encrypted on the digital watermark embedding side, the encryption is decoded here, the original data is restored, and the data is passed to the signature comparison unit 1203.
[0052]
The signature generation means 1202 generates signature data for the transform coefficient by the same method as that on the digital watermark embedding side. However, when encryption or the like is used on the digital watermark embedding side, there is no need to perform encryption here, and the signature is extracted by the signature extraction unit 1201. The generated signature data is passed to the signature comparison unit 1203.
[0053]
The signature comparison unit 1203 compares the signature data extracted by the signature extraction unit 1201 with the signature data generated by the signature generation unit 1202, and determines whether the image data has been tampered based on the comparison. For example, if both signature data match, it is determined that there is no tampering, and if they do not match, it is determined that there is tampering. The determination result is output through a comparison result output terminal 1007.
[0054]
[Effects of First Embodiment]
As described above, according to the first embodiment, even when each bit plane is configured with a plurality of coding passes and arithmetically coded, by changing the arithmetic code censoring point, It is possible to enable the verification side to extract all the embedded signature data. According to the first embodiment, rate control in the encoding process can be used in order to set the data amount after encoding to the target encoding amount. It is possible to output coded data having a code amount to be performed.
[0055]
{1-2. Second Embodiment≫
[Configuration of digital watermark embedding side]
FIG. 4 is a block diagram illustrating a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the second embodiment. In FIG. 4, the same or corresponding components as those in FIG. 1 (first embodiment) are denoted by the same reference numerals. As shown in FIG. 4, the configuration of the digital watermark embedding side of the second embodiment is different from that of the first embodiment (FIG. 1) in that the digital watermark embedding side has an invalid coding path terminating unit 1016. Configuration is different.
[0056]
[Operation on the digital watermark embedding side]
The operation of the configuration of the digital watermark embedding side according to the second embodiment is the same as the operation of the configuration (FIG. 1) of the digital watermark embedding side according to the first embodiment except for the operation of the invalid coding path terminating unit 1016. is there. The invalid coding path truncation unit 1016 illustrated in FIG. 4 includes, in the coding result of the coding pass obtained by the arithmetic coding unit 1013A, the most significant bit plane included in the compressed arithmetic code data in each code block. It is checked whether there is a coding pass that may be terminated in the coding pass of the bit plane on the LSB side. As a result, if there is an encoding pass that is determined to be discontinued, the encoding pass is changed so as not to be included in the compressed arithmetically encoded data.
[0057]
Specifically, the invalid coding pass terminating unit 1016 determines that the arithmetic coding order of the bit planes is the slowest in the coding pass (the order of one bit plane is the coding pass 1,..., N−1, n). In this case, the encoding path is checked in the order of encoding paths n, n-1,..., 1), and the encoding path including significant data is obtained for the first time. Then, the arithmetic code censoring point is changed as an encoding pass in which the encoded data including the significant data is included in the compressed arithmetic code data. Here, the meaningful data means that at least one “1” is included in the bit to be encoded. If all the bits to be encoded are “0”, the bits corresponding to the encoding path that has not been encoded at the time of decoding, even if the encoding path is not included in the compressed arithmetically encoded data, If decoding is performed as “0” (this is handled in a normal decoding process), the value of the conversion coefficient after embedding the signature can be made the same between the embedding apparatus and the verification apparatus. Therefore, as described above, it is possible to abort an encoding pass having no significant data. Except for the above, the operation on the digital watermark embedding side in the second embodiment is the same as the operation on the digital watermark embedding side in the first embodiment.
[0058]
[Configuration and operation of digital watermark verification side]
The configuration and operation of the digital watermark verification side of the second embodiment are the same as the configuration (FIG. 2) and operation of the digital watermark verification side of the first embodiment.
[0059]
[Effect of Second Embodiment]
As described above, according to the second embodiment, it is determined whether or not there is an unnecessary encoding path among the encoding paths of arithmetic coding. Is not included in the arithmetically coded data after compression, the amount of arithmetic coding can be reduced and data with a high compression ratio can be obtained while ensuring that the same transform coefficient value can be decoded.
[0060]
{1-3. Third Embodiment≫
In the configuration of the digital watermark embedding side of the first embodiment described above, it is necessary to perform arithmetic coding by the arithmetic coding unit 1013A on all transform coefficients in which the signature data is embedded. On the other hand, in the configuration of the digital watermark embedding side of the third embodiment, arithmetic coding is initialized / terminated on a bit plane basis so that arithmetic coding can be independently processed in each bit plane. Only the bit plane in which the signature data is embedded can be arithmetically encoded by the arithmetic encoding unit 1013A, and the arithmetic encoding by the arithmetic encoding unit 1013A for the bit plane in which the signature data has not been embedded can be omitted.
[0061]
[Configuration of digital watermark embedding side]
FIG. 5 is a block diagram illustrating a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the third embodiment. In FIG. 5, the same reference numerals are given to the same or corresponding components as those in FIG. 1 (first embodiment). As shown in FIG. 5, the configuration on the digital watermark embedding side of the third embodiment has a point that an encoder internal reset unit 1017 is provided and an arithmetic terminal that outputs arithmetically encoded data output from the rate control unit 1014. The point of output to 1004 is different from the configuration of the digital watermark embedding side of the first embodiment (FIG. 1).
[0062]
[Operation on the digital watermark embedding side]
Arithmetic codes used in the arithmetic coding means 1013 include MQ coding used in JPEG2000 and the like. As the input of the MQ encoding, a bit (symbol) to be encoded and a context are used. The context is a probability evaluation model for predicting 0 or 1 of a target pixel from a peripheral image, and is sequentially updated from a predetermined initial value according to a bit input as an encoding target. The arithmetic coding unit 1013 has a register for arithmetic coding therein, and performs arithmetic coding while sequentially updating the register.
[0063]
In order to perform processing independently in each processing unit of arithmetic coding, it is necessary to initialize a context for arithmetic coding and an internal register. Further, at the end of the encoding, it is necessary to perform a terminating process which is a process of discharging a code from a register for arithmetic encoding. In the third embodiment, when arithmetic coding is performed by the arithmetic coding unit 1013, processing is performed independently for each bit plane. Therefore, the encoder internal resetting unit 1017 performs processing for each bit plane. The above-described initialization / termination processing is performed at the start and end.
[0064]
The bit plane encoding path generation unit 1012A performs the same processing as that performed by the bit plane encoding path generation unit 1012 on the transform coefficient in which the signature data obtained by the signature embedding unit 1102 has been embedded. According to the information from the means 1015, the bit plane in which the signature data is not embedded is not changed in bit, so that this process is skipped. Similarly, the arithmetic coding unit 1013A does not change the bits of the bit planes in which the signature data is not embedded according to the information from the coding path control unit 1015. Not performed.
[0065]
However, since the bits of the bit plane in which the signature data is embedded are changed, the bit plane encoding path generation unit 1012A performs the same processing as the bit plane encoding path generation unit 1012. Then, arithmetic coding is performed on the coding pass by the arithmetic coding unit 1013A. At this time, by performing the above-described initialization / termination processing for each bit plane by the encoder internal reset unit 1017, each bit plane can be processed independently, and arithmetic coding of only the bit plane in which the signature data is embedded is performed. Becomes possible.
[0066]
Thereafter, the arithmetic coding data of the bit plane in which the signature data determined by the rate control unit 1014 is not embedded and the arithmetic coding data of the bit plane in which the signature data obtained from the arithmetic coding unit 1013A are embedded are combined. To obtain encoded (compressed) data. Except for the above, the operation of the digital watermark embedding side in the third embodiment is the same as the operation of the digital watermark embedding side in the first embodiment.
[0067]
[Configuration and operation of digital watermark verification side]
The configuration and operation of the digital watermark verification side according to the third embodiment are the same as the configuration (FIG. 2) and operation of the digital watermark verification side according to the first embodiment.
[0068]
[Effects of Third Embodiment]
As described above, according to the third embodiment, in order to independently process each bit plane in arithmetic coding, initialization / termination processing of arithmetic coding is performed. As a result, the arithmetic coding of the bit plane in which the signature data that does not need to be arithmetically encoded again is not embedded is skipped, and only the bit plane in which the signature data that needs to be arithmetically encoded is embedded is arithmetically encoded. And the amount of arithmetic processing can be reduced.
[0069]
{1-4. Fourth embodiment≫
In the configuration of the digital watermark embedding side of the first embodiment described above, it is necessary to perform arithmetic coding by the arithmetic coding unit 1013A on all transform coefficients in which the signature data is embedded. On the other hand, in the configuration of the digital watermark embedding side of the fourth embodiment, the internal information of the encoder of the arithmetic encoding unit 1013 is stored so that the arithmetic encoding by the arithmetic encoding unit 1013A can be restarted halfway. By doing so, it is possible to encode only the bit plane in which the signature data that needs to be subjected to the arithmetic coding by the arithmetic coding unit 1013A is embedded, and the arithmetic coding unit 1013A for the bit plane in which the signature data is not embedded. Arithmetic coding can be omitted.
[0070]
[Configuration of digital watermark embedding side]
FIG. 6 is a block diagram showing a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the fourth embodiment. 6, the same reference numerals are given to the same or corresponding components as those in FIG. 1 (first embodiment). As shown in FIG. 6, the configuration of the digital watermark embedding side of the fourth embodiment has a point that an encoder internal information storage unit 1018 is provided, and an arithmetic code output from the rate control unit 1014 is output to an output terminal 1004. Is different from the configuration on the digital watermark embedding side in the first embodiment (FIG. 1).
[0071]
[Operation on the digital watermark embedding side]
Arithmetic codes used in the arithmetic coding means 1013 include MQ coding used in JPEG2000 and the like. As the input of the MQ encoding, a bit (symbol) to be encoded and a context are used. The context is a probability evaluation model for predicting 0 or 1 of a target pixel from a peripheral image, and is sequentially updated from a predetermined initial value according to a bit input as an encoding target. In addition, arithmetic coding has a register for arithmetic coding therein, and performs arithmetic coding while sequentially updating the register.
[0072]
When arithmetic coding is restarted halfway, it is necessary to keep the internal information (context, register) of the encoder in the same state as when encoding from the initial state. For this purpose, in the fourth embodiment, the encoder internal state storage means 1018 stores the bit plane so that the arithmetic coding can be restarted from the boundary of the bit plane when the arithmetic coding means 1013 performs the arithmetic coding. The internal information of the encoder is stored every time.
[0073]
The bit plane coding path generation unit 1012A performs the same processing as the bit plane coding path generation unit 1012 on the transform coefficient in which the signature data obtained by the signature embedding unit 1102 is embedded. According to the information from the means 1015, the bit plane in which the signature data is not embedded is not changed in bit, so that this process is skipped. Similarly, the arithmetic coding means 1013A does not perform the arithmetic coding of the bit plane. However, the bit plane encoding path generation unit 1012A performs the same processing as that performed by the bit plane encoding path generation unit 1012 because the bits have been changed for the bit plane in which the signature data is embedded. Then, arithmetic coding is performed on the coding pass by the arithmetic coding unit 1013A. At this time, the same internal information as when the bit plane to be encoded is encoded is set in the encoder by using the internal information of the encoder held by the encoder internal state storage unit 1018. , Perform arithmetic coding processing.
[0074]
Thereafter, the arithmetic coding data of the bit plane in which the signature data determined by the rate control unit 1014 is not embedded and the arithmetic coding data of the bit plane in which the signature data obtained from the arithmetic coding unit 1013A are embedded are combined. To obtain encoded (compressed) data. Except for the above, the operation of the digital watermark embedding side of the fourth embodiment is the same as the operation of the digital watermark embedding side of the first embodiment.
[0075]
[Configuration and operation of digital watermark verification side]
The configuration and operation of the digital watermark verification side of the fourth embodiment are the same as the configuration (FIG. 2) and operation of the digital watermark verification side of the first embodiment.
[0076]
[Effect of Fourth Embodiment]
As described above, according to the fourth embodiment, by storing the internal information of the encoder so that arithmetic coding can be restarted halfway, signature data that does not need to be arithmetic-coded again Can be skipped, and only the bit plane in which the signature data that needs to be arithmetically encoded is embedded can be arithmetically encoded, thereby reducing the amount of arithmetic processing.
[0077]
{1-5. Fifth embodiment≫
In the configuration in which the digital watermark embedding of the first embodiment is performed, first, arithmetic coding is performed on the transform coefficient, signature data is embedded, and the coefficient embedded with the signature data is again arithmetically encoded. Coding had to be performed. On the other hand, in the digital watermark embedding configuration according to the fifth embodiment, a bit plane in which signature data is to be embedded is specified in advance before arithmetic coding of a transform coefficient, and the generated signature data is stored in the bit plane. After that, arithmetic coding is performed.
[0078]
[Configuration of digital watermark embedding side]
FIG. 7 is a block diagram illustrating a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the fifth embodiment. 7, the same reference numerals are given to the same or corresponding components as those in FIG. 1 (first embodiment).
[0079]
As shown in FIG. 7, in the configuration of the digital watermark embedding side of the fifth embodiment, the image data input from the input terminal 1001 is generated by the frequency conversion unit 1011 for frequency conversion and the frequency conversion unit 1011. A conversion coefficient storage unit 1021 for storing a conversion coefficient. Further, the configuration of the digital watermark embedding side of the fifth embodiment includes a signature generation unit 1101 for generating signature data from a transform coefficient, a signature embedding unit 1102 for embedding the signature data obtained from the signature generation unit 1101, It has a bit-plane coding path generating unit 1012A for generating a coding pass for bit-plane coding the embedded transform coefficients, and an arithmetic coding unit 1013A for arithmetically coding each coding pass. The compressed data after the encoding / digital watermark embedding generated by the arithmetic encoding unit 1013A is output through the output terminal 1004. A bit plane is input to the signature generation unit 1101, the embedded signature embedding unit 1102, the bit plane encoding path generation unit 1012A, and the arithmetic encoding unit 1013A through the bit plane input terminal 1005.
[0080]
[Operation on the digital watermark embedding side]
As shown in FIG. 7, image data of a target image in which a digital watermark is to be embedded is input to an input terminal 1001. Image data input to the input terminal 1001 is passed to the frequency conversion unit 1011. The frequency transform unit 1011 performs a frequency transform such as a wavelet transform on the input image to obtain a coefficient in a frequency space. The conversion coefficient is stored in the conversion coefficient storage unit 1021.
[0081]
The signature generation unit 1101 generates signature data for the transform coefficient obtained by the frequency conversion unit 1011. The signature data is obtained from the conversion coefficients excluding the coefficients for embedding the generated signature data among the conversion coefficients. More specifically, a hash value obtained by a hash function such as SHA1 using a bit plane other than the embedded bit plane input from the embedded bit plane input terminal 1005 and all bits of the bit plane not used for embedding, A hash value encrypted by an encryption algorithm such as RSA, a part of the hash value, or the like is used as signature data.
[0082]
The signature embedding unit 1102 embeds the signature data obtained from the signature generation unit 1101 into the conversion coefficient stored in the conversion coefficient storage unit 1021. The bit plane to be embedded is a bit plane input from the embedded bit plane input terminal 1005. The embedding position may be a pseudo-random sequence or a position obtained by scrambling with a replacement table.
[0083]
The bit plane coding path generation unit 1012A divides the transform coefficient into which the signature data obtained by the signature embedding unit 1102 is embedded into code blocks of a predetermined size, and converts the code block from MSB to LSB for each code block. In order to encode each bit plane after being expanded into a plurality of bit planes, an encoding path is determined according to a predetermined rule. The arithmetic coding unit 1013A performs arithmetic coding for each coding pass generated by the bit plane coding pass generation unit 1012A to obtain coded (compressed) data. Both the bit plane coding path generation unit 1012A and the arithmetic coding unit 1013A may generate the coding path and perform the arithmetic coding thereof up to the bit plane input from the embedded bit plane input terminal 1005. The coefficient data in which the signature data is embedded and encoded is output through an output terminal 1004 and passed to the configuration on the digital watermark verification side.
[0084]
[Configuration and operation of digital watermark verification side]
The configuration and operation of the digital watermark verification side according to the fifth embodiment are the same as the configuration (FIG. 2) and operation of the digital watermark verification side according to the first embodiment.
[0085]
[Effects of Fifth Embodiment]
As described above, according to the fifth embodiment, by designating the bit plane in which the signature data is to be embedded in advance, the generated signature data is embedded before the transform coefficient is arithmetically encoded, and then the signature is generated. By performing the arithmetic coding of the transform coefficient in which the data is embedded up to the designated bit plane, the arithmetic coding process performed twice in the first embodiment can be reduced to one.
[0086]
{1-6. Sixth embodiment≫
In the configuration of the digital watermark embedding side according to the first embodiment described above, when an encoding path generated for a transform coefficient is arithmetically encoded and rate control is performed, an arithmetic code abort point is determined at a boundary of the encoding path. I was On the other hand, in the configuration of the digital watermark embedding side according to the sixth embodiment, when an arithmetic code censoring point is obtained in advance in rate control, the boundary of the bit plane is set so that the censoring point is not set in the middle of the bit plane. Rate control is performed by providing a constraint condition for setting an arithmetic code termination point only.
[0087]
[Configuration of digital watermark embedding side]
FIG. 8 is a block diagram illustrating a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the sixth embodiment. 8, the same reference numerals are given to the same or corresponding components as those in FIG. 1 (first embodiment). The configuration of the digital watermark embedding side according to the sixth embodiment includes a rate control unit 1019 with constraints, instead of the rate control unit 1014 according to the first embodiment, and the point that the encoding path control unit 1015 is omitted. This is different from the configuration of the digital watermark embedding side of the first embodiment.
[0088]
[Operation on the digital watermark embedding side]
The operation of the configuration on the digital watermark embedding side of the sixth embodiment is the same as that of the digital watermark embedding of the first embodiment except for the operations of the rate control unit with constraint condition 1019, the signature generation unit 1101, and the arithmetic encoding unit 1013A. This is the same as the operation of the configuration on the side.
[0089]
Normally, in the rate control, the arithmetic code break point is determined at the boundary of the coding path so that the image quality of the encoded (compressed) image is optimized. However, the rate control unit 1019 with the constrained condition allows the verification side to extract all the signature data embedded in a certain bit plane, so that the arithmetic code after the encoding pass in the middle of the bit plane is not censored. , Find the arithmetic code censoring point.
[0090]
That is, on the condition that the arithmetic code censoring point is on the bit plane boundary, each coding block obtained by the arithmetic coding unit 1013 is obtained for each code block so that the code amount input from the target code amount input terminal 1003 is obtained. The arithmetic coding amount for each pass is counted, and when the target coding amount is reached, subsequent passes are truncated. By this processing, the arithmetic code censoring point in each code block is determined, and the encoding path included in the compressed arithmetic code data is determined. By applying the condition that the arithmetic code abort point is set to the bit plane boundary, the arithmetic code abort point is set at the bit plane boundary (immediately after the coding path Coding pass C) as shown in FIG. Is set. However, unlike the first embodiment, the arithmetic code censoring point obtained by the rate control is changed by the coding path control unit without considering the image quality. Nevertheless, under such conditions, the rate control can be performed so that compressed data with the optimum image quality can be obtained for the target code amount. Therefore, although the arithmetic code abort point exists at the boundary of the bit plane, the arithmetic code abort point in each code block is not always exactly the same as in FIG. Further, the rate control unit with constraint 1019 sets the bit plane closest to the LSB side among the bit planes included in the arithmetic code data after compression in each code block as the bit plane in which the signature data is embedded.
[0091]
The signature generation unit 1101 generates signature data for the transform coefficient stored in the transform coefficient storage unit 1021. The difference from the first embodiment is that the signature data is generated using the information of the bit plane in which the signature data is embedded, which is obtained by the rate control unit 1019 with the constraint condition.
[0092]
The arithmetic coding unit 1013A performs arithmetic coding for each coding pass generated by the bit plane coding pass generation unit 1012A. The difference from the first embodiment is that arithmetic coding is performed up to the coding pass determined by the rate control unit with constraint condition 1019 to obtain coded (compressed) data. In other respects, the operation of the digital watermark embedding side of the sixth embodiment is the same as the operation of the digital watermark embedding side of the first embodiment.
[0093]
[Configuration and operation of digital watermark verification side]
The configuration and operation of the digital watermark verification side of the sixth embodiment are the same as the configuration (FIG. 2) and operation of the digital watermark verification side of the first embodiment.
[0094]
[Effects of Sixth Embodiment]
As described above, according to the sixth embodiment, even when one bit plane is composed of a plurality of coding passes and arithmetically coded, the arithmetic code censoring point determined by the rate control is determined by the bit control. By performing rate control only on plane boundaries, it is possible to extract all the embedded signature data on the verification side. Usually, the arithmetic code break point is determined at the boundary of the coding path so that the image quality of the encoded (compressed) image is optimized. However, by restricting the arithmetic code break point to the bit plane boundary, Optimal image quality cannot be obtained. However, since the rate control in the encoding process can be used with constraints, the image quality is quasi-optimal (optimal under the condition that the arithmetic code break point is set at the bit plane boundary) for the target code amount. Can be obtained.
[0095]
The configuration of the digital watermark embedding side according to the sixth embodiment may be combined with the configuration of the digital watermark embedding side according to the second to fourth embodiments.
[0096]
{2. Second invention≫
{2-1. Seventh embodiment≫
[Configuration of digital watermark embedding side]
FIG. 9 is a block diagram illustrating a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the seventh embodiment.
[0097]
As shown in FIG. 9, the configuration of the digital watermark embedding side according to the seventh embodiment receives image data input to an input terminal 2001 and data specifying an embedded bit plane input to a bit plane input terminal 2002. And ID information embedding means 2102 for embedding ID information indicating that the digital watermark is embedded in the embedded bit plane input from the input terminal 2002. The configuration of the digital watermark embedding side according to the seventh embodiment is such that, for image data in which ID information is embedded, data input from an embedded data input terminal 2003 is converted into an embedded bit plane input from an input terminal 2002. And a data embedding unit 2104 for embedding the data in the data. The image data in which the data is embedded by the data embedding unit 2104 is output through the output terminal 2004, and is passed to the configuration of the digital watermark verification side described below.
[0098]
[Configuration of Digital Watermark Verification Side]
FIG. 10 is a block diagram showing the configuration of the digital watermark verification side according to the seventh embodiment.
[0099]
As shown in FIG. 10, the configuration of the digital watermark verification side according to the seventh embodiment is to extract ID information from image data to be verified of a digital watermark input to the input terminal 2005, and to extract ID information from the extracted ID information. An ID information extracting unit 2202 for specifying a bit plane in which data is embedded is provided. Further, the configuration on the digital watermark verification side according to the seventh embodiment includes a data extracting unit 2204 that extracts data from image data. The output of the data extraction unit 2204 is output through the output terminal 2006.
[0100]
[Operation on the digital watermark embedding side]
As shown in FIG. 9, image data of a target image in which an electronic watermark is to be embedded is input to an input terminal 2001. The image data input to the input terminal 2001 is pixel data or a conversion coefficient obtained by performing frequency conversion on the pixel data.
[0101]
To the ID information embedding means 2102, a bit plane number in which a digital watermark is embedded is input through an embedded bit plane input terminal 2002. The ID information embedding means 2102 embeds predetermined ID information in the bit plane of the input bit plane number. As shown in FIG. 11, the bit plane in which the digital watermark is embedded may be different for each of the code blocks CB1 to CB8. In the example of FIG. 11, in the code block CB3, N (bits) ID information is embedded in the bit plane of the bit plane number '5' in which the digital watermark is embedded.
[0102]
However, the same bit pattern as the result of embedding the ID information may exist in a bit plane higher than the bit plane in which the ID information is embedded. If the digital watermark is verified under such conditions, it becomes impossible to distinguish which is the real ID information. Therefore, in the above case, the value of at least one bit in the corresponding bit pattern in the upper bit plane should be inverted.
[0103]
The data embedding unit 2104 receives a bit plane number in which a digital watermark is embedded through an embedded bit plane input terminal 2002. The data embedding unit 2104 embeds the data input from the embedded data input terminal 2003 in the bit plane of the bit plane number in which the digital watermark is embedded. In the example of FIG. 11, in the code block CB3, data of M (bits) is embedded in the bit plane of bit plane number '5' in which the digital watermark is embedded, following the embedded ID information.
[0104]
In FIG. 11, N (bits) ID information and M (bits) data are embedded in order from the first bit (the leftmost bit in the lower part of FIG. 11). Alternatively, a position obtained by scrambling with a replacement table can be used. In the example of FIG. 11, one-bit ID information and data are sequentially embedded for one bit of image data. However, one-bit ID information and data are embedded for a plurality of bits of image data. May be. The data size may be added to the head of the data to indicate how many bits the data has been embedded.
[0105]
Also, it is not necessary to embed ID information in a bit plane in which data is embedded, and ID information may be embedded in, for example, one bit plane higher or lower than the bit plane number input from the embedded bit plane input terminal 2002. It may be. Further, instead of embedding the ID information in one bit plane, using a pseudo random sequence or the like with a key as a seed, randomizing the bit plane in which the ID information is embedded, centering on the bit plane in which the data is embedded, ID information can be embedded in a bit plane.
[0106]
Also, by embedding the bit plane number for embedding data together with the ID information, it becomes possible to embed the ID information in an arbitrary bit plane. Referring to the example of FIG. 12, in the code block CB3, the ID information is embedded in the bit plane of the bit plane number '7', and the data is embedded in the bit plane of the bit plane number '5'. Therefore, when embedding the ID information, it is only necessary to embed the bit plane number '5' (“0101” when expressed in binary 4 bits) which is the data embedding.
[0107]
Furthermore, by embedding a plurality of bit plane numbers for embedding data together with ID information, it is possible to divide and embed data in a plurality of bit planes indicated by those bit plane numbers.
[0108]
Further, in order to compress the data amount, a process of cutting off bit planes lower than the bit plane in which ID information and data are embedded can be performed as necessary.
[0109]
After the embedding, the image data after embedding the ID information and the data is output from the image data output terminal 2004. This image data is passed to a configuration on the digital watermark verification side via a network or the like.
[0110]
[Operation on the digital watermark verification side]
As shown in FIG. 10, image data for verifying a digital watermark is input to an input terminal 2005. The image data input to the input terminal 2005 is pixel data or a conversion coefficient obtained by frequency-converting the pixel data.
[0111]
The ID information extracting means 2202 determines the embedding position of the ID information from the upper bit plane of each code block by the same method as when embedding the ID information, and extracts the ID information from the embedded position. Then, a bit plane in which the extracted ID information matches the embedded ID information is obtained, and the bit plane is determined to be the bit plane in which the data is embedded.
[0112]
However, the above description is for the case where ID information is embedded in a bit plane in which data is embedded, and in the case where ID information is embedded on the bit plane one level above or one bit below the bit plane in which data is embedded, As described above, a bit plane in which the extracted ID information matches the embedded ID information is determined, and a bit plane one level lower or one level higher than the bit plane is determined to be a bit plane in which data is embedded. .
[0113]
In addition, when ID information is dispersed and embedded in a plurality of bit planes centering on a bit plane in which data is embedded with a pseudo random sequence or the like using a key as a seed, when searching for ID information, the order from the upper bit plane is determined. In the meantime, a bit plane dispersed in the same manner as when the ID information is embedded is determined, the ID information is extracted from the bit plane, and it is checked whether the bit plane matches the embedded ID information. Can be determined.
[0114]
When the bit plane number in which the data is embedded together with the ID information is embedded, a bit plane in which the extracted ID information matches the embedded ID information is first obtained, and then the bit plane is embedded together with the ID information. Retrieve the bit plane number that has been set. Thereafter, the bit plane indicated by the bit plane number is determined to be the bit plane in which the data is embedded. Referring to the example of FIG. 12, in the code block CB3, ID information can be extracted from the bit plane of bit plane number '7', and by extracting the bit plane number embedded with the ID information, data can be extracted. It can be seen that the embedded bit plane number is “5” (“0101” when expressed in binary 4 bits).
[0115]
Further, when a plurality of bit plane numbers to be embedded together with the ID information are embedded, it is determined that data is embedded in the plurality of bit planes.
[0116]
The data extraction unit 2204 extracts data embedded in the image data from the bit plane obtained by the ID information extraction unit 2202. The extraction is performed by determining the embedding position by the same method as when embedding data, and extracting data from the embedding position. If the data size is added to the head of the data, the data size is extracted, and then the data body is extracted. The extracted data is output through an extraction result output terminal 2006.
[0117]
[Effects of Seventh Embodiment]
As described above, according to the seventh embodiment, at the time of verifying a digital watermark, even if information indicating where the digital watermark is embedded is not obtained from outside, it is possible to use the ID information embedded in the image. , It is possible to specify the bit plane in which the digital watermark is embedded. Therefore, even if a bit plane is cut off for the purpose of reducing the data amount and an image in which a digital watermark is embedded in a bit plane immediately before the cut off is decoded with an arbitrary value, the cut off bit plane is decoded. On the digital watermark verification side, the same frequency conversion is performed again to obtain a conversion coefficient, and ID information indicating that the bit plane has data embedded therein is extracted. Identified and embedded data can be extracted.
[0118]
{2-2. Eighth embodiment≫
In the configuration of the digital watermark embedding side according to the seventh embodiment described above, the digital watermark is always embedded using the same bit pattern as the ID information indicating the bit plane in which the digital watermark is embedded. On the other hand, in the configuration of the digital watermark embedding side according to the eighth embodiment, the same random number as the random number generated in the configuration of the digital watermark verification side is generated, and the random number is used as ID information. Can be used as ID information.
[0119]
[Configuration of digital watermark embedding side]
FIG. 13 is a block diagram illustrating a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the eighth embodiment. In FIG. 13, the same or corresponding components as those in FIG. 9 (seventh embodiment) are denoted by the same reference numerals. As shown in FIG. 13, the configuration of the digital watermark embedding side of the eighth embodiment has a random number generation unit 2112 that receives a seed input to a seed input terminal 2008 and generates a random number. This is different from the configuration of the digital watermark embedding side of the embodiment (FIG. 9).
[0120]
[Configuration of Digital Watermark Verification Side]
FIG. 14 is a block diagram illustrating a configuration (digital watermark detection device) on the digital watermark verification side that performs the digital watermark detection method according to the eighth embodiment. 14, the same reference numerals are given to the same or corresponding components as those in FIG. 10 (seventh embodiment). As shown in FIG. 14, the configuration of the digital watermark verification side according to the eighth embodiment has a random number generation unit 2112 that receives a seed input to a seed input terminal 2009 and generates a random number. This is different from the configuration on the digital watermark verification side of the embodiment (FIG. 10).
[0121]
[Operation on the digital watermark embedding side]
As shown in FIG. 13, the random number generation unit 2112 receives a seed for generating a random number from a seed input terminal 2008 and generates a random number. When embedding the ID information in the bit plane in which the digital watermark is embedded, the ID information embedding unit 2102 embeds the ID information using the random number generated by the random number generation unit 2112 as a bit pattern of the ID information. By using random numbers in this way, different ID information is embedded for each code block. Except for the above points, the operation of the digital watermark embedding side in the eighth embodiment is the same as the operation of the digital watermark embedding side in the seventh embodiment.
[0122]
[Operation on the digital watermark verification side]
As shown in FIG. 14, a random number generation unit 2112 receives a seed for generating a random number from a seed input terminal 2009 and generates a random number. The same seed as the digital watermark embedding side is input to the digital watermark verification side, and the same random number is generated. The ID information extracting means 2202 extracts ID information from the upper bit plane of each code block, and obtains a bit plane in which the extracted ID information matches the embedded ID information. Used as a bit pattern of ID information. Of course, the bit pattern used is different for each code block, but is the same bit pattern as the digital watermark embedding side. Except for the above, the operation of the digital watermark verification side in the eighth embodiment is the same as the operation of the digital watermark verification side in the seventh embodiment.
[0123]
[Effects of Eighth Embodiment]
As described above, according to the eighth embodiment, at the time of verifying a digital watermark, even if information on the position where the digital watermark is embedded is not obtained from the outside, the ID information embedded in the image can be used. The bit plane in which the digital watermark is embedded can be specified. Therefore, even if a bit plane is cut off for the purpose of reducing the data amount and an image in which a digital watermark is embedded in a bit plane immediately before the cut off is decoded with an arbitrary value, the cut off bit plane is decoded. On the digital watermark verification side, the same frequency conversion is performed again to obtain a conversion coefficient, and ID information indicating that the bit plane has data embedded therein is extracted. Identified and embedded data can be extracted.
[0124]
According to the eighth embodiment, when embedding ID information in order to specify a bit plane in which a digital watermark is embedded, a random number generated in the same manner on the digital watermark embedding side and the digital watermark verification side is used. It can be used as a bit pattern of information. Therefore, even in the same image, the embedded ID information does not always have the same value, and it is possible to prevent a malicious third party from easily specifying the ID information.
[0125]
{2-3. Ninth embodiment≫
The configuration of the digital watermark verification side according to the ninth embodiment is to generate signature data from image data in order to detect tampering, and to embed the signature data as a digital watermark, in a bit plane in which the signature data is embedded. In addition to embedding ID information indicating that the signature data has been embedded, it indicates which part of the image data that was targeted when obtaining the signature data in order to know from which part of the image data the signature data was generated at the time of detection. Embed information at the same time.
[0126]
[Configuration of digital watermark embedding side]
FIG. 15 is a block diagram illustrating a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the ninth embodiment. 15, the same reference numerals are given to the same or corresponding components as those in FIG. 9 (seventh embodiment).
[0127]
As shown in FIG. 15, the configuration on the digital watermark embedding side of the ninth embodiment receives image data input to an input terminal 2001 and data specifying an embedded bit plane input to a bit plane input terminal 2002. And ID information embedding means 2102 for embedding ID information indicating that the digital watermark is embedded in the embedded bit plane input from the input terminal 2002. The configuration of the digital watermark embedding side according to the ninth embodiment includes a signature generation information embedding unit 2106 for embedding information indicating which part of the image data subjected to hash generation when obtaining the signature data. Further, the configuration of the digital watermark embedding side of the ninth embodiment includes a signature generation unit 2108 that generates signature data from image data, and a signature embedding unit 2110 that embeds the signature data obtained from the signature generation unit 2108 into image data. Have. The embedded image data generated by the signature embedding unit 2110 is output through the output terminal 2004. The output image data is passed, for example, via a network to a configuration on the digital watermark verification side described below.
[0128]
[Configuration of Digital Watermark Verification Side]
FIG. 16 is a block diagram illustrating a configuration (digital watermark detection device) on the digital watermark verification side according to the ninth embodiment. 16, the same reference numerals are given to the same or corresponding components as those in FIG. 10 (seventh embodiment).
[0129]
As shown in FIG. 16, the configuration of the digital watermark verification side of the ninth embodiment extracts ID information from image data input through an input terminal 2005, and extracts a bit in which signature data is embedded from the extracted ID information. An ID information extracting unit 2202 for specifying a plane and a signature extracting unit 2206 for extracting signature data embedded on the embedding side are provided. The configuration of the digital watermark verification side according to the ninth embodiment includes a signature generation information extraction unit 2208 that extracts information indicating which part of image data subjected to hash generation at the time of obtaining signature data, Signature generation means 2210 for generating signature data from image data based on the signature generation information. Further, the configuration on the digital watermark verification side according to the ninth embodiment includes a signature comparison unit 2212 that compares the extracted signature data with the generated signature data. The comparison result output from the signature comparison generation unit 2210 is output through the output terminal 2007.
[0130]
[Operation on the digital watermark embedding side]
As shown in FIG. 15, image data of a target image in which an electronic watermark is embedded is input to an input terminal 2001. The image data input to the input terminal 2001 is pixel data or a conversion coefficient obtained by performing frequency conversion on the pixel data.
[0131]
An ID information embedding unit 2102 receives a bit plane number in which a digital watermark is embedded from an embedded bit plane input terminal 2002, and embeds predetermined ID information in the bit plane. FIG. 17 is an explanatory diagram of the digital watermark embedding method according to the ninth embodiment. In FIG. 17, code blocks in which a digital watermark is embedded are only code blocks CB2, CB4, CB6, and CB8 having even-numbered code block numbers, and the bit planes in which the digital watermark is embedded may be different for each code block. . In the example of FIG. 17, in the code block CB2, N (bits) ID information is embedded in the bit plane of the bit plane number '6' in which the digital watermark is embedded. However, if the same bit pattern as the result of embedding the ID information exists in a bit plane higher than the bit plane in which the ID information is embedded, the same processing as in the seventh embodiment is performed.
[0132]
The signature generation information embedding means 2106 receives the bit plane number in which the digital watermark is embedded from the embedding bit plane input terminal 2002, and stores in the bit plane which part of the image data that has been subjected to hash generation when obtaining the signature data. Embed information indicating whether or not it was.
[0133]
More specifically, in a code block that is not a target for embedding the signature data, which part of the data for which the hash is to be generated when obtaining the signature data is identified when the digital watermark verification side obtains the signature data. Therefore, of the image data used for hash generation, the lowest bit plane number is embedded in the bit plane to be embedded. For example, FIG. 17 shows an example in which a hash is obtained from the data of the code blocks CB1 and CB2, signature data is generated, and embedded in the code block CB2. Since the code block CB2 embeds the ID information together with the signature in the bit plane of the bit plane number '6', the digital watermark verification side extracts the ID information to determine the bit plane in which the signature data is embedded. Image data used for hash generation when generating signature data (all bits of bit plane numbers '7' to '10' and bit planes of bit plane number '6' can be determined. , All bits not used to embed the signature data). However, since the ID information is not embedded in the code block CB1, the digital watermark verification side cannot identify which part is used for hash generation at the time of signature generation. Therefore, as shown in FIG. 17, when a bit plane with a bit plane number “3” or less is cut off and a hash is generated using bit plane data with a bit plane number “4” or more, a code not to be embedded with signature data is used. In the block CB1, of the data used for hash generation, the lowest bit plane number “4” (“0100” when expressed in binary 4 bits) is stored in the bit plane to which the data of the codebook CB2 is embedded. Embed it.
[0134]
The signature generation unit 2108 generates signature data for the image data. The bit plane number in which the digital watermark is embedded is input from the embedded bit plane input terminal 2002, and the signature data is obtained from the image data excluding the bits for embedding the generated signature data. Specifically, in the code blocks CB1 and CB2 of FIG. 17, all the bit planes of the bit plane numbers '4' to '10' in the code block CB1 and the bit plane numbers '7' to '10' in the code block CB2 The hash value obtained by a hash function such as SHA1 or the hash value using all bits not used for embedding the signature data among all the bit planes of the Data encrypted by RSA or the like, a part of a hash value, or the like is used as signature data.
[0135]
The signature embedding unit 2110 receives the bit plane number in which the digital watermark is embedded from the embedding bit plane input terminal 2002, and embeds the signature data obtained from the signature generation unit 2101 in the bit plane. In the example of FIG. 17, in the code block CB2, for the bit plane of the bit plane number '6' in which the digital watermark is embedded, the ID data and the signature generation information which have already been embedded are followed by the signature data of M (bits). Is embedded.
[0136]
In FIG. 17, ID information, signature generation information, and signature data are embedded in order from the first bit, but the bit positions to be embedded can be scrambled by a pseudo random sequence or a replacement table. Also, one bit of ID information, signature generation information, and signature data are embedded in order for one bit of image data, but one bit of ID information, signature generation information, and signature are embedded for a plurality of bits of image data. Data may be embedded.
[0137]
Further, similarly to the seventh embodiment, it is not always necessary to embed ID information in the same bit plane as signature generation information and signature data. Further, the ID information, the signature generation information, and the signature data may be dispersedly embedded in a plurality of bit planes.
[0138]
In order to compress the data amount, similarly to the seventh embodiment, the bit planes lower than the bit plane in which the ID information, the signature generation information, and the signature data are embedded (for example, the bit plane number in the code block CB2 in FIG. 17) It is also possible to perform a process of cutting off bit planes that are not used for generation of a hash (for example, bit plane number “3” or less in code block CB1 in FIG. 17) that are not used for hash generation.
[0139]
The image data after the ID information, the signature generation information, and the signature data output from the signature embedding unit 2110 are embedded are output through the image data output terminal 2004.
[0140]
[Operation of Digital Watermark Verification Example]
As shown in FIG. 16, image data for verifying a digital watermark is input to an input terminal 2005. The image data input to the input terminal 2005 is pixel data or a conversion coefficient obtained by frequency-converting the pixel data.
[0141]
The ID information extracting unit 2202 determines the embedding position of the ID information from the upper bit plane in the code block in which the digital watermark is to be embedded by the same method as when the ID information is embedded, and extracts the ID information from the embedding position. Then, a bit plane in which the extracted ID information matches the embedded ID information is obtained, and the bit plane is determined to be the bit plane in which the signature generation information and the signature data are embedded.
[0142]
Note that even if the ID information is embedded in a bit plane different from the signature generation information or the signature data, or if the ID information, the signature generation information, and the signature data are dispersed and embedded in different bit planes, the seventh The bit plane in which the signature generation information and the signature data are embedded can be obtained as in the embodiment.
[0143]
The signature extracting unit 2206 extracts the signature data embedded in the image data from the bit plane obtained by the ID information extracting unit 2202. The extraction is performed by determining the embedding position by the same method as that at the time of embedding the signature data, and extracting the signature data from the embedding position. If the hash value or the like is encrypted on the digital watermark embedding side, the encryption is decoded here, the original data is restored, and the data is passed to the signature comparison unit 2212.
[0144]
The signature generation information extraction unit 2208 extracts the signature generation information embedded in the image data from the bit plane obtained by the ID information extraction unit 2202. For extraction, determine the embedding position using the same method as when embedding the signature generation information, and extract information indicating which part of the image data used in the generation of the hash when obtaining the signature data from the embedding position Do with. The extracted signature generation information is passed to the signature generation unit 2210.
[0145]
The signature generation unit 2210 generates signature data for the image data based on the information obtained from the ID information extraction unit 2202 and the signature generation information extraction unit 2208 by the same method as that on the digital watermark embedding side. That is, for a code block in which signature data is embedded, based on the bit plane obtained by the ID information extraction unit 2202, image data that has been subjected to hash generation when obtaining signature data can be determined. For the code block in which no data is embedded, the signature data is similarly obtained from the information obtained by the signature generation information extraction unit 2208 (the lowest bit plane number of the image data subjected to hash generation). At this time, it is possible to determine the image data that has been subjected to hash generation.
[0146]
However, if encryption or the like is used on the digital watermark embedding side, there is no need to perform encryption here, and the signature extraction unit 2206 decodes the encryption. The generated signature data is passed to the signature comparison unit 2212.
[0147]
The signature comparison unit 2212 compares the signature data extracted by the signature extraction unit 2206 with the signature data generated by the signature generation unit 2210. For example, if both signature data match, there is no tampering, and if they do not match, there is tampering, and the result is output through the comparison result output terminal 2007.
[0148]
[Effects of Ninth Embodiment]
As described above, according to the ninth embodiment, ID information indicating a bit plane in which a digital watermark is embedded and information relating to the position of data to be hashed when obtaining signature data are obtained. By embedding the signature generation information shown in the image, even if the information cannot be obtained from the outside, the bit plane in which the signature data is embedded and the image data used for hash generation when obtaining the signature data are specified. can do. Therefore, in order to reduce the amount of data, even if an image in which a bit plane that is not used for signature generation or embedding of signature data is cut off is decoded with an arbitrary value, the cut-off bit plane is decoded with an arbitrary value. On the watermark verification side, the same frequency conversion is performed again to obtain a conversion coefficient, and furthermore, signature data and signature generation information are embedded by extracting ID information indicating a bit plane in which the signature data and signature generation information are embedded. The specified bit plane can be specified, and the embedded signature data can be extracted. Furthermore, by extracting the signature generation information indicating which part of the data for which the hash is to be generated when obtaining the signature data, it is also possible to determine from which part of the image data the signature data was generated. The signature data can be generated in the same manner as the side. As a result, a correct tampering detection result can be obtained.
[0149]
{3. Third invention≫
{3-1. Tenth embodiment≫
[Configuration of digital watermark embedding side]
FIG. 18 is a block diagram showing a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the tenth embodiment.
[0150]
As shown in FIG. 18, the configuration of the digital watermark embedding side of the tenth embodiment includes a blocking unit 3100 that divides image data input to the input terminal 3001 into one or a plurality of blocks. Further, the configuration of the digital watermark embedding side according to the tenth embodiment receives the image data blocked by the blocking unit 3100 and the data specifying the embedded bit plane input through the embedded bit plane input terminal 3003, and performs the blocking. There is an upper bit plane evaluation unit 3101 for examining the upper bit plane of the image data obtained. Furthermore, the configuration of the digital watermark embedding side according to the tenth embodiment includes image data blocked by the blocking unit 3100, data specifying an embedded bit plane input through the embedded bit plane input terminal 3003, and upper bit plane evaluation. It receives the evaluation result output from the means 3101 and the data input through the embedded data input terminal 3002, and embeds the data input from the embedded data input terminal 3002 at a position based on the evaluation result of the designated bit plane of the image data. An embedding unit 3103 is provided. Image data after data embedding output from the embedding unit 3103 is output through an output terminal 3004.
[0151]
FIG. 19 is a block diagram showing an example in which the configuration (digital watermark embedding device) of the digital watermark embedding side that performs the digital watermark embedding method according to the tenth embodiment is applied to a JPEG2000 compressor. In FIG. 19, the same or corresponding components as those in FIG. 18 are denoted by the same reference numerals.
[0152]
As shown in FIG. 19, in addition to the configuration of FIG. 18, the JPEG2000 compressor includes a color conversion unit 3050 that converts a color space when input image data is color image data, and performs a tile division of the input image data. It has a tile dividing means 3054 for performing a wavelet transform, a wavelet transform means 3051 for performing a wavelet transform, a quantizing means 3052 for quantizing a wavelet coefficient, and an encoding means 3053 for encoding a coefficient in which a digital watermark is embedded. The bit stream encoded by the encoding means 3053 is output through an embedded image bit stream output terminal 3005.
[0153]
[Operation on the digital watermark verification side]
FIG. 22 is a block diagram illustrating a configuration (digital watermark detection device) on the digital watermark verification side that performs the digital watermark detection method according to the tenth embodiment.
[0154]
As shown in FIG. 22, the configuration on the digital watermark verification side according to the tenth embodiment includes a blocking unit 3200 that divides image data input through the input terminal 3010 into blocks. Further, the configuration of the digital watermark verification side according to the tenth embodiment is configured such that the image data blocked by the blocking means 3200 and the data which is input via the extraction bit plane input terminal 3013 and specifies the bit plane to be extracted are included. An upper bit plane evaluation unit 3201 for checking the upper bit plane of the received and blocked image data is provided. Further, the configuration of the digital watermark verification side according to the tenth embodiment includes the image data blocked by the blocking unit 3200, the data specifying the extraction bit plane input through the extraction bit plane input terminal 3013, and the upper bit plane. Extraction means 3203 is provided for receiving the evaluation result output from the evaluation means 3201 and extracting data from the position based on the evaluation result in the designated extraction bit plane for the input image data. The extraction result output from the extraction means 3203 is output through an output terminal 3012.
[0155]
FIG. 23 is a block diagram illustrating an example in which the configuration (digital watermark detection device) on the digital watermark verification side that performs the digital watermark detection method according to the tenth embodiment is applied to a JPEG2000 decompressor. 23, components that are the same as or correspond to those in FIG. 22 are given the same reference numerals. As shown in FIG. 23, when applied to a JPEG2000 decompressor, a decoding unit 3204 that decodes a JPEG2000 bit stream and outputs wavelet coefficients and block information is provided instead of the blocking unit 3200 in FIG.
[0156]
[Operation on the digital watermark embedding side]
As shown in FIG. 18, image data of a target image in which a digital watermark is to be embedded is input to an input terminal 3001. When embedding a digital watermark directly into pixel data, the input data is pixel data. In the case of a digital watermark in a frequency space, input data is wavelet coefficients or DCT coefficients.
[0157]
Image data input to input terminal 3001 is passed to blocking means 3100. The blocking unit 3100 divides the input image data into blocks of M × N size. In the case of a digital watermark on pixel data, the block is an M × N pixel block. In the case of a digital watermark on a frequency space, the block is a block of M × N coefficients on a coefficient space after wavelet transform or DCT. This block may be constituted by a coefficient group having the same position in the pixel space and having a different frequency, or may be constituted by a coefficient group having a close position in the pixel space and having the same frequency.
[0158]
The upper bit plane evaluation unit 3101 labels image data in ascending order of the effect on image quality. Normally, changes made to smooth regions (regions with only low frequency components) are more perceived than changes made to complex regions (regions with high frequency components nearby), so complex regions Labeling to give high priority to the neighborhood.
[0159]
FIG. 20 is an explanatory diagram of the digital watermark embedding method according to the tenth embodiment. In FIG. 20, coefficients 1 to 8 are arranged in order from the left side in the horizontal direction, and bit plane numbers '0' to '10' are arranged in order from the bottom in the vertical direction. In FIG. 20, the bit plane with bit plane number '5' is a bit plane used for information embedding, and black portions are coefficient bits used for conventional information embedding. In FIG. 20, the shaded portion is a coefficient bit having a non-zero value in the upper bit plane, and the cross-hatched portion is a non-zero coefficient bit in which the upper bit plane is 0.
[0160]
For example, labeling is performed for each image data unit according to the level of data that is higher than the embedded bit plane (for example, the bit plane with the bit plane number “5” in FIG. 20). In this case, the labels correspond to the order when sorting is performed based on the data level (for example, in FIG. 20, the order of coefficients 2, 5, 8, 1). In addition, labeling is performed on image data having a value of 0 in the order in which non-zero image data exists around the range of the value 0.
[0161]
This can be expressed as follows. Assuming that the data of the bit plane higher than the embedded bit plane is a (x, y), labeling is performed on image data with | a (x, y) |> 0 in descending order of a (x, y). Do. Further, for image data where | a (x, y) | = 0, the absolute sum of the values of the image data in the vicinity of 8, ie,
(| A (x + 1, y) | + | a (x, y + 1) | + | a (x-1, y) | + | a (x, y-1) | + | a (x + 1, y + 1) | + | A (x-1, y + 1) | + | a (x + 1, y-1) | + | a (x-1, y-1) |)
Labeling is performed in descending order of.
[0162]
The embedding unit 3103 performs embedding in the order in which the upper bit plane evaluation unit 3101 performs labeling. In the embedding, a 1-bit embedding message is sequentially embedded in each image data in the order in which the labeling is performed. X image data is used for embedding an X-bit message. Further, the size of the message may be embedded at the head of the message. In this case, X + Y (Y is the number of bits required to embed the message length) image data is used.
[0163]
FIG. 21 is an explanatory diagram of another example of the digital watermark embedding method according to the tenth embodiment. 21 shows an example in which coefficients 1 to 8 are arranged in order from the left side in the horizontal direction, and bit plane numbers '0' to '10' are arranged in order from the bottom in the vertical direction. In FIG. 21, the bit plane with bit plane number '5' is a bit plane used for information embedding, and the black solid portions are coefficient bits used for conventional information embedding. In FIG. 21, the shaded portion is a coefficient bit having a non-zero value in the upper bit plane, and the cross-hatched portion is a non-zero coefficient bit in which the upper bit plane is 0. Further, near the center of FIG. 21, embedded bit planes of each group (after sorting by the value of the upper bit plane) are shown, and from the left to the right, coefficient bits having a large value and coefficient bits having a small value are arranged from left to right. It is drawn. FIG. 21 shows a case where an image or an embedding coefficient is divided into a plurality of groups and one bit is embedded in each group unit. In FIG. 21, the method of dividing into a plurality of groups is such that a large value coefficient is equally allocated to each group.
[0164]
FIG. 21 illustrates a method of calculating 1-bit information based on a plurality of bits of information and embedding the 1-bit information obtained by the calculation. As shown in FIG. 21, for example, when data of a group for embedding 1 bit is “0101” (4 bits), an exclusive OR (XOR) of the data of a plurality of bits is calculated. In this case, the result of the XOR operation is 0. This operation result 0 is compared with a value (1 bit) to be embedded in this group. To change.
[0165]
The signature data is embedded in the image data in the order of the labeling having the least influence on the image quality obtained as described above, and the image data in which the signature data is embedded is passed through the image data output terminal 3004 to the embedded image. Output through the data output terminal.
[0166]
[Operation on the digital watermark verification side]
As shown in FIG. 22, image data of a target image for which a digital watermark is to be verified is input to an input terminal 3010. When a digital watermark is directly embedded in pixel data, input data is pixel data. In the case of a digital watermark in a frequency space, input data is wavelet coefficients or DCT coefficients. Image data input to input terminal 3010 is passed to blocking means 3200. The blocking unit 3200 divides the input image data into M × N size blocks. In the case of a digital watermark on pixel data, the block is an M × N pixel block. In the case of a digital watermark on a frequency space, the block is a block of M × N coefficients on a coefficient space after wavelet transform or DCT.
[0167]
Using the bit plane information input from the extracted bit plane input terminal 3013, the upper bit plane evaluation unit 3201 labels the image data in the same manner as the upper bit plane evaluation unit 3101 (FIG. 18) on the digital watermark embedding side. A one-bit message is extracted from one coefficient in the labeling order. If the message length is embedded at the beginning of the message, the message length is extracted before extracting the message body. The message extracted by the extracting means 3203 is output through an extraction result output terminal 3012.
[0168]
[Effects of Tenth Embodiment]
As described above, according to the tenth embodiment, the embedded data can be embedded in a portion having little influence on the image quality, so that the image quality of the image in which the digital watermark is embedded can be improved. In addition, the digital watermark verification side detects the data embedding position using the information of the bit plane higher than the bit plane in which the digital watermark is embedded. At the stage when the bit plane is obtained, the digital watermark can be extracted.
[0169]
{3-2. Eleventh embodiment≫
[Configuration of digital watermark embedding side]
FIG. 24 is a block diagram showing a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the eleventh embodiment. 24, components that are the same as or correspond to those in FIG. 18 (the tenth embodiment) are given the same reference numerals. As shown in FIG. 24, the configuration of the digital watermark embedding side of the eleventh embodiment is different from the digital watermark embedding side of the tenth embodiment in that a block determination unit 3102 and a zero block marking unit 3104 are provided. (FIG. 18).
[0170]
[Configuration of Digital Watermark Verification Side]
FIG. 26 is a block diagram illustrating a configuration (digital watermark detection device) on the digital watermark verification side that performs the digital watermark detection method according to the eleventh embodiment. 26, the same reference numerals are given to the same or corresponding components as those in FIG. 22 (tenth embodiment). As shown in FIG. 26, the configuration of the digital watermark verification side of the eleventh embodiment differs from the configuration of the digital watermark verification side of the tenth embodiment (FIG. 22) in having a block determination unit 3202. I do.
[0171]
[Operation on the digital watermark embedding side]
As shown in FIG. 24, image data of a target image in which an electronic watermark is embedded is input to an input terminal 3001. When embedding a digital watermark directly into pixel data, the input data is pixel data. In the case of a digital watermark in a frequency space, input data is wavelet coefficients or DCT coefficients.
[0172]
Image data input to input terminal 3001 is passed to blocking means 3100. The blocking unit 3100 divides the input image data into blocks of M × N size. In the case of a digital watermark on pixel data, the block is an M × N pixel block. In the case of a digital watermark on a frequency space, the block is a block of M × N coefficients on a coefficient space after wavelet transform or DCT. This block may be constituted by a coefficient group having the same position in the pixel space and having a different frequency, or may be constituted by a coefficient group having a close position in the pixel space and having the same frequency.
[0173]
The block determination unit 3102 scans a bit plane specified by data input from the embedded bit plane input terminal 3003 in block units. As a result of the scanning, an all0 (all 0) block in which the data of the bit plane is all 0 (zero) is marked.
[0174]
The upper bit plane evaluation unit 3101 evaluates the upper bit plane and performs labeling on the image data in ascending order of the effect on the image quality. Normally, changes made to smooth regions (regions with only low frequency components) are more perceived than changes made to complex regions (regions with high frequency components nearby), so complex regions Labeling to give high priority to the neighborhood. The labeling method is the same as in the case of the tenth embodiment.
[0175]
The embedding unit 3103 includes a message for image data that belongs to a block that has not been determined to be an all0 block by the block determination unit 3102, and that is determined by the upper bit plane evaluation unit 3101 to have significant data in the upper bit plane. Perform embedding.
[0176]
If the message is larger than the number of image data under the above conditions, furthermore, the data belonging to the block determined to be the all0 block by the block determination unit 3102 and significant data in the upper bit plane is determined by the upper bit plane evaluation unit 3101. The message is also embedded in the determined image data. The embedding position of the message is determined before embedding the message.
[0177]
The zero block marking unit 3104 performs marking on the all0 block in which the data of the embedded bit plane is all 0 in the block in which the message is embedded. The marking is performed by setting at least one image data of a portion not used for embedding the message to 1 on the bit plane in which the message of the block is embedded. The image data set to 1 may not be used for embedding a message, and may have a large evaluation value by the upper bit plane evaluation unit 3101.
[0178]
FIG. 25 is a block diagram illustrating another example of the configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the eleventh embodiment. The zero block marking unit 3104 performs marking on all blocks in which a message is to be embedded. Marking is performed by setting at least one image data of a portion not used for embedding a message to 1 on a bit plane in which a message of a block is embedded. The image data set to 1 may not be used for embedding a message, and may have a large evaluation value by the high-order bit plane evaluation unit. In the case of embedding a signature or the like, it is necessary to calculate a signature value after performing marking. In that case, the configuration is as shown in FIG.
[0179]
[Operation on the digital watermark verification side]
As shown in FIG. 26, the block determination unit 3202 and the upper bit plane evaluation unit 3201 perform block marking in the same manner as on the digital watermark embedding side. The extracting unit 3203 extracts the message from the image data in the same manner as the method for determining the embedding position on the signature embedding side.
[0180]
The digital watermark embedding side avoids embedding in a block where bit plane data is 0, and the digital watermark verification side avoids extracting a block where bit plane data is 0. The zero block marking means 3104 performs marking in order to synchronize the embedding position of the message between the embedding side and the verification side, so that the state of the block where the bit plane data is 0 does not change between the embedding side and the verification side. The operation of the digital watermark verification side according to the eleventh embodiment other than the above is the same as the operation of the digital watermark verification side according to the tenth embodiment.
[0181]
[Effects of Eleventh Embodiment]
According to the eleventh embodiment, since the embedding in the zero bit plane is avoided, the coding efficiency can be improved.
[0182]
{3-3. Twelfth embodiment≫
[Configuration of digital watermark embedding side]
FIG. 27 is a block diagram illustrating a configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the twelfth embodiment. In FIG. 27, the same or corresponding components as those in FIG. 18 (the tenth embodiment) are denoted by the same reference numerals. As shown in FIG. 27, the configuration of the digital watermark embedding side according to the twelfth embodiment includes an embedding coefficient determining unit 3301 that determines an embedding target coefficient from an embedding bit plane and image data, and stores the determined embedding coefficient. And an embedding unit 3103 for embedding the embedding data in the input image data.
[0183]
[Configuration of Digital Watermark Verification Side]
FIG. 28 is a block diagram illustrating a configuration (digital watermark detection device) on the digital watermark verification side that performs the digital watermark detection method according to the twelfth embodiment. In FIG. 28, the same or corresponding components as those in FIG. 22 (the tenth embodiment) are denoted by the same reference numerals. As shown in FIG. 28, the configuration of the digital watermark verification side according to the twelfth embodiment includes an embedding coefficient determination unit 3311 that determines an embedding target coefficient from an embedding bit plane and image data, and stores the determined embedding coefficient. And an extraction unit 3203 for extracting an embedded image from image data.
[0184]
[Operation on the digital watermark embedding side]
As shown in FIG. 27, the embedding coefficient determination unit 3301 determines an embedding position based on the input embedding bit plane information. As a determination method, the method of the upper bit plane evaluation unit 3101 (FIGS. 18 and 24) or the block determination unit 3102 (FIG. 24) of the tenth and eleventh embodiments may be used.
[0185]
The embedding position storage means 3302 stores the embedding coefficient determined by the embedding coefficient determining means 3301.
[0186]
The embedding unit 3103 embeds information in the bit plane input from the embedding bit plane input terminal 3003 with respect to the coefficient determined by the embedding coefficient determination 3301.
[0187]
FIG. 29 is an explanatory diagram of the digital watermark embedding method according to the twelfth embodiment. In FIG. 29, coefficients 1 to 8 are arranged in order from the left side in the horizontal direction, and bit plane numbers '0' to '10' are arranged in order from the bottom in the vertical direction. In FIG. 29, the bit plane of bit plane number '5' is a bit plane used for information embedding, and black portions are coefficient bits used for conventional information embedding. In FIG. 29, the shaded portions are bit planes (parts used in addition to information embedding) of the coefficients used for embedding which are lower than the embedding bit plane.
[0188]
FIG. 30 is an explanatory diagram of another example of the digital watermark embedding method according to the twelfth embodiment. In FIG. 30, coefficients 1 to 8 are arranged in order from the left side in the horizontal direction, and bit plane numbers '0' to '10' are arranged in order from the bottom in the vertical direction. In FIG. 30, the bit planes with bit plane numbers “0”, “4”, and “7” are bit planes used for information embedding, and black-filled portions are coefficient bits used for conventional information embedding. . In FIG. 30, the shaded portion is a bit plane lower than the embedding bit plane of the coefficient used for embedding (a portion used in addition to embedding information).
[0189]
As shown in FIG. 29 or FIG. 30, the coefficients determined by the embedding coefficient determination means 3301 and the coefficients actually used for embedding are acquired from the embedding position storage means 3302, and the coefficients on the LSB side of the embedding bit plane are obtained. The information is embedded in the bit plane.
[0190]
The portion below the bit plane in which the digital watermark is embedded is set to all 0 (all0), all 1 (all1), or an intermediate value so as to minimize the error value from the original coefficient value, or the data is embedded by embedding. If you did not change it, leave it alone. Further, when all the bits are set to zero (all0) or all ones (all1), the embedding position is easily determined by evaluating those values, and thus the lower bits may be filled (filled) with a random value. In this case, since the data embedding capacity is wasted, information is embedded in lower bits.
[0191]
In the case of a digital watermark for falsification detection, signature data may be embedded in the bit plane input from the embedded bit plane input terminal 3003, and the LSB side may be used for embedding a message. At the time of digital watermark verification, the message may be embedded in the bit plane order so as to support progressive transmission in units of one bit plane. Except for the points described above, the operation of the digital watermark embedding side of the twelfth embodiment is the same as the operation of the digital watermark embedding side of the tenth and eleventh embodiments.
[0192]
[Operation on the digital watermark verification side]
As shown in FIG. 28, the embedding coefficient determination unit 3311 determines the embedding position based on the input detection bit plane information. As the determination method, the method of the upper bit plane evaluation unit 3201 (FIG. 22) in the tenth embodiment or the method of the block determination unit 3202 (FIG. 26) in the eleventh embodiment may be used.
[0193]
The embedding position storage unit 3312 stores the embedding coefficient determined by the embedding coefficient determination unit 3311.
[0194]
The extracting unit 3203 extracts information from the determined coefficient. Also, a coefficient determined by the embedding coefficient determining unit 3311 and a coefficient actually used for extraction is obtained from the embedding position storage unit 3312, and information is extracted from a bit plane on the LSB side of the extracted bit plane. (See FIGS. 29 and 30). The operation of the digital watermark verification side according to the twelfth embodiment other than the above is the same as the operation of the digital watermark verification side according to the tenth and eleventh embodiments.
[0195]
[Effects of Twelfth Embodiment]
As described above, according to the twelfth embodiment, when information is embedded in the bit plane between the MSB and the LSB, the information can be embedded by embedding the information in the data of the lower bit plane. The amount can be increased dramatically.
[0196]
≪4. Other forms of use≫
The configurations of the first to twelfth embodiments can be configured by a computer system. In this case, the digital watermark embedding method and the digital watermark detection method in each of the above embodiments can be executed according to an application program installed in the computer system. As a method of installing the application program, there are methods such as installation from a storage medium on which the installation program is recorded and download via the Internet.
[0197]
Since the configurations of the first to twelfth embodiments can be configured by a computer system, it is also possible to provide a system that combines the functions of some configurations of the first to twelfth embodiments. It is possible.
[0198]
【The invention's effect】
According to the first aspect, even when each bit plane is composed of a plurality of encoding passes and is arithmetically encoded, all of the embedded signature data can be taken out on the verification side.
[0199]
According to the second aspect, when verifying a digital watermark, it is possible to specify the bit plane in which the digital watermark is embedded, even if information indicating where the digital watermark is embedded is not obtained from outside. . Therefore, it is possible to specify the bit plane in which the digital watermark is embedded, and to extract the embedded data.
[0200]
Further, according to the third aspect, since the embedded data can be embedded in a portion where the influence of the image quality is small, the image quality can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration (digital watermark embedding device) on a digital watermark embedding side that executes a digital watermark embedding method according to a first embodiment of the first invention.
FIG. 2 is a block diagram illustrating a configuration (digital watermark detection device) on the digital watermark verification side according to the first to sixth embodiments of the first invention;
FIGS. 3A and 3B are explanatory diagrams of an encoding path control method according to the first embodiment of the first invention. FIGS.
FIG. 4 is a block diagram showing a configuration (digital watermark embedding device) of a digital watermark embedding side that performs a digital watermark embedding method according to a second embodiment of the first invention.
FIG. 5 is a block diagram showing a configuration (digital watermark embedding device) on a digital watermark embedding side for performing a digital watermark embedding method according to a third embodiment of the first invention.
FIG. 6 is a block diagram showing a configuration (digital watermark embedding device) on a digital watermark embedding side that executes a digital watermark embedding method according to a fourth embodiment of the first invention.
FIG. 7 is a block diagram showing a configuration (digital watermark embedding device) of a digital watermark embedding side that performs a digital watermark embedding method according to a fifth embodiment of the first invention.
FIG. 8 is a block diagram showing a configuration (digital watermark embedding device) on a digital watermark embedding side for performing a digital watermark embedding method according to a sixth embodiment of the first invention.
FIG. 9 is a block diagram illustrating a configuration (digital watermark embedding device) on a digital watermark embedding side that performs a digital watermark embedding method according to a seventh embodiment of the second invention.
FIG. 10 is a block diagram showing a configuration (digital watermark detection device) on a digital watermark verification side for implementing a digital watermark detection method according to a seventh embodiment of the second invention.
FIG. 11 is an explanatory diagram of a digital watermark embedding method according to a seventh embodiment of the second invention.
FIG. 12 is an explanatory diagram of another example of the digital watermark embedding method according to the seventh embodiment of the second invention.
FIG. 13 is a block diagram showing a configuration (digital watermark embedding device) on a digital watermark embedding side for performing a digital watermark embedding method according to an eighth embodiment of the second invention.
FIG. 14 is a block diagram illustrating a configuration (digital watermark detection device) on a digital watermark verification side that performs a digital watermark detection method according to an eighth embodiment of the second invention.
FIG. 15 is a block diagram showing a configuration (digital watermark embedding device) on a digital watermark embedding side that executes a digital watermark embedding method according to a ninth embodiment of the second invention.
FIG. 16 is a block diagram showing a configuration (digital watermark detection device) on a digital watermark verification side for implementing a digital watermark detection method according to a ninth embodiment of the second invention.
FIG. 17 is an explanatory diagram of a digital watermark embedding method according to a ninth embodiment of the second invention.
FIG. 18 is a block diagram showing a configuration (digital watermark embedding device) on a digital watermark embedding side that performs a digital watermark embedding method according to a tenth embodiment of the third invention.
FIG. 19 is a block diagram showing an example in which a configuration (digital watermark embedding device) on the digital watermark embedding side that performs a digital watermark embedding method according to a tenth embodiment of the third invention is applied to a JPEG2000 compressor.
FIG. 20 is an explanatory diagram of a digital watermark embedding method according to a tenth embodiment of the third invention.
FIG. 21 is an explanatory diagram of another example of the digital watermark embedding method according to the tenth embodiment of the third invention.
FIG. 22 is a block diagram illustrating a configuration (digital watermark detection device) on a digital watermark verification side that performs a digital watermark detection method according to a tenth embodiment of the third invention.
FIG. 23 is a block diagram showing an example in which a configuration (digital watermark detection device) on the digital watermark verification side that performs a digital watermark detection method according to a tenth embodiment of the third invention is applied to a JPEG2000 decompressor.
FIG. 24 is a block diagram showing a configuration (digital watermark embedding device) on a digital watermark embedding side for performing a digital watermark embedding method according to an eleventh embodiment of the third invention.
FIG. 25 is a block diagram showing another example of the configuration (digital watermark embedding device) on the digital watermark embedding side that performs the digital watermark embedding method according to the eleventh embodiment of the third invention.
FIG. 26 is a block diagram illustrating a configuration (digital watermark detection device) on the digital watermark verification side that performs a digital watermark detection method according to an eleventh embodiment of the third invention.
FIG. 27 is a block diagram showing a configuration (digital watermark embedding device) of a digital watermark embedding side that performs a digital watermark embedding method according to a twelfth embodiment of the third invention.
FIG. 28 is a block diagram showing a configuration (digital watermark detection device) on the digital watermark verification side that performs a digital watermark detection method according to a twelfth embodiment of the third invention.
FIG. 29 is an explanatory diagram of a digital watermark embedding method according to a twelfth embodiment of the third invention.
FIG. 30 is an explanatory diagram of another example of the digital watermark embedding method according to the twelfth embodiment of the third invention.
FIG. 31 is an explanatory diagram of the concept of a bit plane.
FIG. 32 is an explanatory diagram of an operation of embedding a fragile digital watermark in a bitmap image.
FIG. 33 is an explanatory diagram of an operation of verifying a fragile digital watermark.
FIG. 34 is a block diagram illustrating a configuration for encoding coefficients in a frequency space.
FIG. 35 is an explanatory diagram showing arithmetic coding when one type of coding pass is generated for one bit plane.
FIG. 36 is an explanatory diagram showing arithmetic coding when three types of coding passes are generated for one bit plane.
FIG. 37 is an explanatory diagram showing a case where bit planes with bit plane numbers “2” and below are cut off and a digital watermark is embedded in the bit plane with bit plane number “3”.
FIG. 38A is an explanatory diagram showing a case where all censored bit planes are set to “0” at the time of decoding, and FIG. FIG. 11 is an explanatory diagram showing a case where the most significant bit plane is a non-zero coefficient.
FIG. 39 is an explanatory diagram showing a region suitable for embedding information and a region not suitable for embedding information.
[Explanation of symbols]
1011 frequency conversion means,
1012 bit plane coding path generating means,
1012A bit plane coding path generating means,
1013 arithmetic coding means,
1013A arithmetic coding means,
1014 rate control means,
1015 coding path control means,
1016 invalid coding pass truncation means,
1017 encoder reset means,
1018 encoder internal state storage means,
1019 rate control means with control condition,
1021 conversion coefficient storage means,
1031 decryption means,
1101 signature generation means,
1102 signature embedding means,
1201 signature extraction means;
1202 signature generation means;
1203 signature comparison means,
2102 ID information embedding means,
2104 data embedding means,
2106 signature generation information embedding means,
2108 signature generation means,
2110 signature embedding means,
2112 random number generating means,
2202 ID information extracting means,
2204 data extraction means,
2206 signature extraction means,
2208 signature generation information extraction means;
2210 signature generation means;
2212 signature comparison means;
3050 color conversion means,
3051 Wavelet transform means,
3052 quantization means,
3053 encoding means,
3054 tile dividing means,
3100 blocking means,
3101 upper bit plane evaluation means,
3102 block determination means,
3103 embedding means,
3104 zero block marking means,
3200 blocking means,
3201 upper bit plane evaluation means,
3202 a block determining means,
3203 extraction means,
3204 decoding means,
3301 embedding coefficient determination means,
3302 embedding position storage means,
3311 embedding coefficient determining means;
3312 embedding position storage means.

Claims (36)

A digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side,
Expanding the input image data into a plurality of bit planes from the most significant bit to the least significant bit, and generating one or more types of first encoding passes for each bit plane;
Arithmetically encoding the data of each bit plane according to the first encoding pass to generate first encoded data;
Controlling the arithmetic coding amount in the arithmetic coding from a target code amount, and determining an arithmetic code censoring point;
Changing the obtained arithmetic code abort point to a bit plane boundary if the obtained arithmetic code abort point is not at a bit plane boundary;
Generating signature data from the input image data;
Embedding signature data in the input image data;
Developing the image data in which the signature data is embedded into a plurality of bit planes from the most significant bit to the least significant bit, and generating one or more types of second encoding passes for each bit plane;
Arithmetically encoding the data of each of the bit planes according to the second encoding pass until the arithmetic code discontinuation point to generate second encoded data. A digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side,
Expanding the input image data into a plurality of bit planes from the most significant bit to the least significant bit, and generating one or more types of first encoding passes for each bit plane;
Arithmetically encoding the data of each bit plane according to the first encoding pass to generate first encoded data;
Controlling the arithmetic coding amount in the arithmetic coding from the generated arithmetic code and the target code amount, and determining the arithmetic code censoring point by limiting the arithmetic code censoring point to a bit plane boundary;
Generating signature data from the input image data;
Embedding signature data in the input image data;
Developing the image data in which the signature data is embedded into a plurality of bit planes, and generating one or more types of second encoding passes for each bit plane;
Arithmetically encoding the data of each of the bit planes according to the second encoding pass until the arithmetic code discontinuation point to generate second encoded data. The method further comprises a step of preventing unnecessary encoding paths of the second encoding path after arithmetically encoding the image data in which the signature data is embedded from being included in the compressed arithmetic code data. The digital watermark embedding method according to claim 1. In the step of generating the second encoded data, arithmetic coding is initialized / terminated on a bit plane basis, so that arithmetic coding can be independently processed on each bit plane, and signature data is embedded. 3. The digital watermark embedding method according to claim 1, wherein arithmetic coding for a non-existing bit plane is omitted. In the step of generating the second encoded data, arithmetic coding can be restarted halfway, and the processing time can be reduced by omitting arithmetic coding for bit planes in which signature data is not embedded. The digital watermark embedding method according to claim 1. A digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side,
Inputting bit plane data for designating a bit plane in which signature data is to be embedded;
Generating signature data from the input image data according to the designated bit plane;
Embedding the generated signature data in the input image data;
Developing the image data in which the signature data is embedded into a plurality of bit planes from the most significant bit to the least significant bit, and generating one or more types of encoding paths for each bit plane;
Arithmetically encoding image data in which signature data is embedded according to the encoding pass up to the designated bit plane. A digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side,
Embedding ID information indicating a bit plane in which an electronic watermark is embedded;
Embedding data in a bit plane specified by the ID information. A digital watermark detection method performed on image data by a configuration of a digital watermark verification side,
Extracting ID information embedded in image data by the digital watermark embedding method according to claim 7, and specifying a bit plane in which the data is embedded;
Extracting data from the specified bit plane. A digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side,
Embedding ID information indicating a bit plane in which an electronic watermark is embedded;
Embedding information on the image data targeted when obtaining signature data;
Generating signature data from the image data;
Embedding the generated signature data in the image data. A digital watermark detection method performed on image data by a configuration of a digital watermark verification side,
Extracting the ID information embedded in the image data by the digital watermark embedding method according to claim 9, and specifying a bit plane in which the signature data is embedded;
Extracting signature data from the specified bit plane;
Extracting signature generation information from the specified bit plane;
Generating signature data from the extracted signature generation information;
Comparing the extracted signature data with the generated signature data. The digital watermark embedding method according to claim 7, wherein a random number generated by a random number generation unit is used as the ID information. 12. The digital watermark detection method according to claim 8, wherein a random number generated by a random number generation unit having the same configuration as the random number generation unit according to claim 11 is used as the ID information. A digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side,
A bit plane for embedding information is specified for input image data, data of a bit plane higher than the bit plane for embedding this information is evaluated, and labeling indicating the order of the position where the information is embedded is performed based on the evaluation result. Steps and
Embedding embedded data in the input image data in accordance with the order indicated by the labeling. A digital watermark detection method performed on image data by a configuration of a digital watermark verification side,
14. Receiving image data in which data has been embedded by the digital watermark embedding method according to claim 13.
A bit plane for extracting information with respect to the received image data is designated, data of a bit plane higher than the designated bit plane is evaluated, and an order of a position where the information is embedded is determined based on the evaluation result. Performing a labeling indicating
Extracting embedded data from the received image data in accordance with the order indicated by the labeling. A digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side,
Dividing the input image data into a plurality of blocks;
Scanning the designated bit plane in block units to identify all 0 blocks in which the data of the bit plane is all 0s;
Embedding embedded data in the input image data,
14. The digital watermark embedding method according to claim 13, wherein in the step of embedding the embedded data, data is embedded in a block other than the all-zero block. A digital watermark detection method performed on image data by a configuration of a digital watermark verification side,
Receiving image data in which data is embedded by the digital watermark embedding method according to claim 15;
Dividing the input image data into a plurality of blocks;
Scanning the designated bit plane in block units to identify all 0 blocks in which the data of the bit plane is all 0s;
A bit plane for extracting information with respect to the received image data is designated, data of a bit plane higher than the designated bit plane is evaluated, and an order of a position where the information is embedded is determined based on the evaluation result. Performing a labeling indicating
Extracting embedded data from the received image data according to the order indicated by the labeling,
The digital watermark detection method according to claim 1, wherein in the step of extracting the data, data is extracted from blocks other than the all-zero block. A digital watermark embedding method executed on image data by a configuration of a digital watermark embedding side,
A bit plane in which information is embedded in the input image data is specified, and a position in which the information is embedded is specified;
Storing the embedding position;
Embedding the message information in a bit plane lower than the position where the information is to be embedded. A digital watermark detection method performed on image data by a configuration of a digital watermark verification side,
Receiving image data in which data is embedded by the digital watermark embedding method according to claim 17;
A bit plane for embedding information in the received image data is specified, and a position for embedding information is specified;
Storing the embedding position;
Extracting message information from a bit plane lower than the position where the information is embedded. An electronic watermark embedding device for embedding an electronic watermark in image data,
A first bit plane encoding path generating means for expanding input image data into a plurality of bit planes from the most significant bit to the least significant bit and generating one or a plurality of types of first encoding paths for each bit plane When,
First arithmetic encoding means for arithmetically encoding the data of each of the bit planes to generate first encoded data according to the first encoding pass;
Rate control means for controlling the arithmetic coding amount in the arithmetic coding from the target code amount, and determining the arithmetic code cutoff point,
Encoding path control means for changing the obtained arithmetic code abort point to a bit plane boundary when the obtained arithmetic code abort point is not at a bit plane boundary;
Signature generation means for generating signature data from the input image data;
Signature embedding means for embedding signature data in the input image data;
A second bit for expanding the image data in which the signature data is embedded into a plurality of bit planes from the most significant bit to the least significant bit, and generating one or more types of second encoding passes for each bit plane Plane encoding path generating means;
And a second arithmetic encoding unit that arithmetically encodes the data of each bit plane according to the second encoding pass and generates second encoded data up to the arithmetic code cutoff point. Digital watermark embedding device. An electronic watermark embedding device for embedding an electronic watermark in image data,
A first bit plane encoding path generating means for expanding input image data into a plurality of bit planes from the most significant bit to the least significant bit and generating one or a plurality of types of first encoding paths for each bit plane When,
First arithmetic encoding means for arithmetically encoding the data of each of the bit planes to generate first encoded data according to the first encoding pass;
Rate control means with constraint conditions for controlling the arithmetic coding amount in the arithmetic coding from the generated arithmetic code and the target code amount, and limiting the arithmetic code cutoff point to a bit plane boundary to determine the arithmetic code cutoff point When,
Signature generation means for generating signature data from the input image data;
Signature embedding means for embedding signature data in the input image data;
A second bit plane encoding path generating means for expanding the image data in which the signature data is embedded into a plurality of bit planes and generating one or a plurality of types of second encoding paths for each bit plane;
And a second arithmetic encoding unit that arithmetically encodes the data of each bit plane according to the second encoding pass and generates second encoded data up to the arithmetic code cutoff point. Digital watermark embedding device. An invalid encoding path terminating means for preventing unnecessary encoding paths of the second encoding path after arithmetically encoding the image data in which the signature data is embedded from being included in the compressed arithmetic code data 21. The digital watermark embedding device according to claim 19, wherein: In the second arithmetic coding means, arithmetic coding is initialized / terminated in units of bit planes, so that arithmetic coding can be independently processed in each bit plane, and bit planes in which signature data is not embedded. 21. The digital watermark embedding device according to claim 19, further comprising an encoding reset unit for omitting arithmetic encoding of the digital watermark. In the second arithmetic coding means, there is provided an encoder internal state storage means for storing the internal state of the encoder of the first arithmetic coding means so that the arithmetic coding can be restarted halfway. 21. The digital watermark embedding device according to claim 19, wherein the arithmetic coding by the second arithmetic coding means for a bit plane in which signature data is not embedded is omitted. An electronic watermark embedding device for embedding an electronic watermark in image data,
Signature generation means for generating signature data from input image data in accordance with embedded bit plane data specifying a bit plane in which signature data is embedded;
Signature embedding means for embedding signature data in the input image data;
Bit plane coding path generation means for expanding the image data in which the signature data is embedded into a plurality of bit planes from the most significant bit to the least significant bit, and generating one or a plurality of types of coding paths for each bit plane When,
An electronic watermark embedding device, comprising: arithmetic coding means for arithmetically coding data of each bit plane according to the coding path up to the designated bit plane to generate coded data. An electronic watermark embedding device for embedding an electronic watermark in image data,
ID information embedding means for embedding ID information indicating a bit plane in which an electronic watermark is embedded,
Data embedding means for embedding data in a bit plane specified by the ID information. An electronic watermark detection device for detecting an electronic watermark from image data,
An ID information extracting unit for extracting ID information embedded in image data by the digital watermark embedding device according to claim 25, and identifying a bit plane in which the data is embedded.
An electronic watermark detection device, comprising: data extraction means for extracting data from a specified bit plane. An electronic watermark embedding device for embedding an electronic watermark in image data,
ID information embedding means for embedding ID information indicating a bit plane in which an electronic watermark is embedded,
Signature generation information embedding means for embedding information regarding the image data targeted when obtaining signature data,
Signature generation means for generating signature data from the image data;
A digital watermark embedding device, comprising: signature embedding means for embedding the generated signature data in the image data. An electronic watermark detection device for detecting an electronic watermark from image data,
28. ID information extracting means for extracting ID information embedded in image data by the digital watermark embedding device according to claim 27, and identifying a bit plane in which signature data is embedded.
Signature generation information extraction means for extracting signature data from the specified bit plane;
Signature extraction means for extracting signature generation information from the specified bit plane;
Signature generation means for generating signature data from the extracted signature generation information;
A digital watermark detection device, comprising: signature comparison means for comparing the extracted signature data with the generated signature data. Having a random number generating means for generating a random number,
28. The digital watermark embedding device according to claim 25, wherein a random number generated by the random number generation unit is used as the ID information. A random number generation unit having the same configuration as the random number generation unit according to claim 29,
29. The digital watermark detection device according to claim 26, wherein the random number generated by the random number generation unit is used as the ID information. An electronic watermark embedding device for embedding an electronic watermark in image data,
A bit plane in which information is to be embedded is specified for input image data, data of a bit plane higher than the bit plane in which the information is embedded is evaluated, and labeling indicating the order of the information embedding position is performed based on the evaluation result. First upper bit plane evaluation means;
An electronic watermark embedding device, comprising: an embedding unit that embeds embedded data in the input image data in the order indicated by the labeling. An electronic watermark detection device for detecting an electronic watermark from image data,
Means for receiving image data in which data is embedded by the digital watermark embedding apparatus according to claim 31;
A bit plane for extracting information with respect to the received image data is designated, data of a bit plane higher than the designated bit plane is evaluated, and an order of a position where the information is embedded is determined based on the evaluation result. Second higher-order bit plane evaluation means for performing labeling indicating
Extracting means for extracting embedded data from the received image data in accordance with the order indicated by the labeling. An electronic watermark embedding device for embedding an electronic watermark in image data,
Blocking means for dividing the input image data into a plurality of blocks;
Block determining means for scanning the designated bit plane in block units and identifying all 0 blocks in which all data of the bit plane is 0;
Means for embedding embedded data in the input image data,
The digital watermark embedding device according to claim 31, wherein the embedding unit embeds data in a block other than the all-zero block. An electronic watermark detection device for detecting an electronic watermark from image data,
Blocking means for receiving image data embedded with data by the digital watermark embedding device according to claim 33, and dividing input image data into a plurality of blocks,
Block determining means for scanning the designated bit plane in block units and identifying all 0 blocks in which all data of the bit plane is 0;
A bit plane for extracting information with respect to the received image data is designated, data of a bit plane higher than the designated bit plane is evaluated, and an order of a position where the information is embedded is determined based on the evaluation result. Second higher-order bit plane evaluation means for performing labeling indicating
Extracting means for extracting embedded data from the received image data according to the order indicated by the labeling,
A digital watermark detection device, wherein the extraction means extracts data from blocks other than the all-zero block. An electronic watermark embedding device for embedding an electronic watermark in image data,
A bit plane in which information is to be embedded in the input image data is specified, and an embedding coefficient determination unit that specifies a position in which the information is to be embedded,
An embedding position storing means for storing the embedding position;
An electronic watermark embedding apparatus, comprising: an embedding unit that embeds message information in a bit plane lower than a position where the information is embedded. An electronic watermark detection device for detecting an electronic watermark from image data,
36. An image data in which data is embedded by the digital watermark embedding device according to claim 35, a bit plane in which information is embedded in the received image data is specified, and an embedding coefficient determination for specifying a position in which the information is embedded is specified. Means,
An embedding position storing means for storing the embedding position;
Extraction means for extracting message information from a bit plane lower than a position where the information is embedded.

Images