CN1207892C - Method and device for inserting digital image into electronic water-print and detecting method - Google Patents
Method and device for inserting digital image into electronic water-print and detecting method Download PDFInfo
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- CN1207892C CN1207892C CN 02156019 CN02156019A CN1207892C CN 1207892 C CN1207892 C CN 1207892C CN 02156019 CN02156019 CN 02156019 CN 02156019 A CN02156019 A CN 02156019A CN 1207892 C CN1207892 C CN 1207892C
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Abstract
The present invention relates to a method and a device for inserting an electronic watermark into a digital image and detecting the electronic watermark, which is characterized in that one image is divided into a plurality of pieces; different electronic watermark data is embedded into each piece by a DCT transformer (103), an electronic watermark data inserting device (104) and an IDCT transformer (107); at the time, an electronic watermark data inserting list (105) and an electronic watermark data list (106) which are used for inserting different electronic watermarks into different image pieces are referred.
Description
Technical field
The present invention relates to the digital processing field, relate to the recognition data (electronic watermark data) that to have customizing messages more specifically and embed or insert technology in the digital picture.
Background technology
In recent years, illegally carry out duplicating of digital picture and become a problem.In order to prevent this type of bootlegging, considered DID is encoded, just and the playback system that only has a legitimate secret can reproduce decoded numerical data.Yet in case password is decrypted, this system can't prevent replication subsequently.
Therefore, in order to prevent illegally using and duplicating of digital picture, considered to use a kind of method, wherein customizing messages was embedded in the data image by (refer to describe below electronic watermark data).For the watermark data that is used for digital picture of this kind, can use such as two visual and not visible electron-like watermark datas.
The visible electronic watermark data is by becoming directly perceived visual to image synthetic specific word or code.Though the visible electronic watermark data that inserts this kind can cause the reduction of picture quality, it can prevent the illegal conversion to user's digital picture intuitively.
The open No. of Japan Patent flat-disclosed the example of a visual electronic watermark data among the 8-241403.In this example, when the visible electronic watermark data is synthesized in the original image, under the situation that does not change color component, the brightness composition that only changes corresponding to the pixel of the dark-coloured part of electronic watermark data by a scaled value just can be synthesized to electronic watermark data in the original image.Scaled value is by color component, and the pixel value of random number and electronic watermark data determines.
Opposite, under the situation of not visible electronic watermark data, when electronic watermark data is embedded in the image, and prevent under the situation of picture quality reduction, can cause damage hardly to deriving from the picture quality of inserting electronic watermark data, thereby the electronic watermark data that embeds not directly perceived visual.Be embedded in the image if can discern author's information,, just can identify the author by detecting this electronic watermark data even carrying out after the bootlegging as electronic watermark data.In addition, forbid the information as electronic watermark data of duplicating if embedded, when reproducing unit detects when duplicating prohibition information, for example, reproducing unit can notify user images for forbidding copy data, or starts duplicating in the reproducing unit and forbid duplicating of mechanism restriction video tape recorder or similar device.
As a kind of not visible electronic watermark data is embedded method in the digital picture, in the method, customizing messages as electronic watermark data is embedded in certain part, and can not cause too much influence to picture quality (for example least significant bit of pixel (LSB) or similar quantity).Yet in the method, electronic watermark data can be deleted from image easily.For example, if having the image of electronic watermark data to carry out low-pass filtering to embedding, the information of the LSB of pixel can be lost, thereby electronic watermark data is under the situation of no any perceptible damage and deleted.In addition, as a kind of Image Compression, it reduces data volume by reducing to the amount of information in the less part of picture quality influence, carry out the compression and decompression process by view data, thereby can under to the less situation of picture quality influence, delete electronic watermark data electronic watermark data with embedding.
In addition, open the patent application spy of Japan and disclosed another kind of example among the flat 6-315131.Its described content is, when image being reproduced by the similitude of utilizing image in the successive frame, detect when promptly using the perimeter to replace this zone, the zone that this regional picture quality also can not be damaged, thus and the specific region is embedded in this zone by changing the data will be converted the zone.This method by reconstructed image with the following method, is at first discerned by embedded the zone and the transitional information of recognition data with the forfeiture signal section when duplicating image, proofreaies and correct identified region with the peripheral data in the identified region then.
Simultaneously disclosed a kind of method in Japanese kokai publication hei 5-30466, wherein the frequency of picture signal is converted, and embeds the information that frequency is lower than the video frequency scope that has been converted.The method is taken out original image signal with high pass filter, and extracts the recognition data that embeds with low pass filter.
As another one frequency inverted example, in the method, image is carried out frequency inverted, and after finishing frequency inverted, in picture signal, embed zone (on April 22nd, 1996, " Nikkei electronics " No.660,13 pages) with strong frequency content.The method is by electronic watermark data is embedded in the zone with strong frequency content, thereby even image is carried out such as compression and decompression process or filtering, electronic watermark data can not lost yet.As long as initial data is damaged, electronic watermark data just can not be deleted.In addition,, the interference between electronic watermark data can be prevented, by embedding data, the decrease in image quality of electronic watermark data can be prevented to have embedded in addition by adopting random number according to normal distribution.
The method that embeds electronic watermark data is as follows, with DCT (discrete cosine transform) or similar approach original image is converted to frequency content, in frequency domain, select to represent n the data f (1) of high value, f (2), ... .f (n), from average be 0 and variance be to select electronic watermark data w (1), w (2) 1 the normal distribution, ... w (n), calculate each i with following formula.
F(i)＝f(i)+α×|f(i)|×w(i)
Wherein α is a conversion coefficient.
By F (i) is carried out anti-dct transform, obtain to embed the image of electronic watermark data.
Carry out the detection of electronic watermark data in the following method.In this detection method, and the electronic watermark data w (i) of original image f (i) and candidate (wherein i is 1,2 ... must be known n).
At first, the image transitions that will have electronic watermark data with DCT is a frequency content, corresponding to the f (1) that in frequency domain, has embedded electronic watermark data, f (2) ... the element value of f (n) is converted into F (1), and F (2) ... F (n).Calculate and obtain the statistics similarity degree of w (i) and W (i) by f (i) and F (i) with following formula.
w(i)＝(F(i)-f(i))/f(i)
Then, use inner product of vector and following formula to calculate the statistics similarity degree of w (i) and W (i).
C＝W·w/(WD/wD)
Wherein: W=(W (1), W (2) ..., W (n));
w＝(w(1)，w(2)，...，w(n))；
The absolute value of WD=vector W
The absolute value of wD=vector w; And
Inner product for vector.
When adding up similarity degree C, can predict to have embedded electronic watermark data greater than some particular value.
If with in the electronic watermark data embedded images, is effectively with the method when the author with original image detects the digital picture that is suspect to be the bootlegging product.The method needs original image, thereby when detecting the view data that is suspect to be the bootlegging product, the author can detect electronic watermark data, yet,, thereby in each terminal of transcriber, all can't detect electronic watermark data because transcriber does not possess original image.
Therefore, the method is improved, and used it for terminal is handled, be used in particular for mpeg system.In the method, original image is split into the piece of 8 pixels * 8 pixels, and electronic watermark data is embedded into as in the piece of processing unit and from wherein extracting electronic watermark data.
Carry out the telescopiny of electronic watermark data with following technology.At first, after in the mpeg decode technology of frequency domain, having carried out the conversion of discrete cosine, in alternating component from lower frequency content sequential definition f (1), f (2), ... f (n), from average be 0 and variance to be 1 normal distribution select w (1), w (2), ... w (n), calculate each i with following formula:
F(i)＝f(i)+α×avg(f(i))×w(i)
Wherein α is a conversion coefficient, and avg (f (i)) is the part mean value of average absolute of three points of vicinity of f (i).
Then, replace f (i) to carry out the decode procedure of MPEG subsequently with F (i).
With following processes electronic watermark data is detected.In this detection method, do not need original image, but only need know electronic watermark data candidate value w (i) (wherein i is 1,2,3 ... n).
In the decompression of finishing MPEG or decode procedure, in the frequency domain of the piece behind re-quantization, determine F (1) in proper order from lower frequency content, F (2) ... F (n).Three some F (i-1) of the vicinity of F (i), F (i), the average absolute that reaches F (i+1) is defined as part mean value avg (F (i)), and electronic watermark data W (i) calculates with following formula:
W(i)＝F(i)/avg(F(i))
And to each i computed image " with " WF (i).
Then, the inner product with vector reaches the statistics similarity degree that following formula calculates w (i) and WF (i).
C＝WF·w/(WFD×wD)
When adding up similarity degree, can think to have embedded electronic watermark data greater than some particular value.
In the example that Japanese kokai publication hei 6-315131 is disclosed, electronic watermark information does not embed in all frames, thereby just can't prevent bootlegging for the frame that does not embed eletric watermark.In addition, this example hypothesis successive frame is a rest image, and does not have variation in successive frame, thereby in the film image that comprises the rapid movement image, can't discern the zone that wherein embeds electronic watermark data, makes it can't embed electronic watermark data.
In addition, in the example that Japanese kokai publication hei 5-30466 is disclosed, electronic watermark data is embedded into frequency and is lower than image is carried out in the frequency domain of frequency domain of frequency inverted, thereby uses high pass filter easily electronic watermark data to be deleted.
In addition, after image being carried out frequency inverted, electronic watermark data is embedded in the example of part stronger in the frequency content, electronic watermark data can't be deleted by filter or similar approach.Yet, when embedding a plurality of electronic watermark datas in the image, there is a problem, if promptly a plurality of electronic watermark data is embedded in the same frequency, electronic watermark data is interfering with each other, thereby has just reduced its detectability when detecting.
Summary of the invention
An object of the present invention is electronic watermark data inserter and detector, even wherein when a plurality of electronic watermark datas are inserted in the images, it can the phase mutual interference yet, and when detecting, can detect electronic watermark data accurately.
In the method according to insertion recognition data of the present invention (electronic watermark data), image to each piece of j * k pixel (wherein j and k are natural number) carries out frequency inverted, and when electronic watermark data is inserted in the frequency content that is converted, after the kind to the electronic watermark data that will insert changes, each piece is all inserted electronic watermark data, thereby under the non-interfering situation electronic watermark data is being inserted each other, and each piece is being detected.More specifically, also provide electronic watermark data insertion position table, it is represented in which piece in any electronic watermark data insertion image, and a suitable electronic watermark data is inserted in the zone shown in the region list.When the detected electrons watermark data, electronic watermark data extraction table similar during with insertion is used to the detected electrons watermark data.
In the present invention, when inserting a plurality of electronic watermark datas in the image, each piece is inserted different electronic watermark datas, thereby under the situation of not disturbing mutually and damaging, insert electronic watermark data, even same when embedding a plurality of electronic watermark data, detected electrons watermark data that also can be correct.
Description of drawings
Fig. 1 is the block diagram that inserts device according to electronic watermark data of the present invention;
Fig. 2 is the block diagram according to electronic watermark data checkout gear of the present invention;
Fig. 3 is the schematic diagram to every kind the insertion position of electronic watermark data in image.
Embodiment
Below with reference to corresponding accompanying drawing embodiments of the invention are described in detail.
The block diagram of electronic watermark data insertion device when Fig. 1 inserts in the view data for electronic watermark data in n.
With reference to figure 1, the embodiment of insertion device according to the invention comprise j * k pixel that output takes out from image piece positional information dct transform device 103 and this information carried out such as discrete cosine transform (DCT), and after orthogonal transform dateout; An electronic watermark data insertion position table 105, the piece position of each class in image of the n electron-like watermark data that its record will insert; One electronic watermark data table 106, its storage n electron-like watermark data; One electronic watermark data inserter 104, it extracts the electronic watermark data that is suitable for according to electronic watermark data insertion position table 105 and with dct transform device 103 from electronic watermark data table 106, and after the DCT conversion electronic watermark data is inserted in the data; And IDCT transducer 107, it carries out inverse discrete cosine transformation (IDCT) in DCT conversion back to the data in the piece, wherein inserts data in piece.
Fig. 2 is the block diagram of the checkout gear that is used for electronic watermark data when inserting n electron-like watermark data in the view data.
With reference to figure 2, comprise according to the example of checkout gear of the present invention j * k pixel that output takes out from image piece positional information dct transform device 203 and this information carried out such as discrete cosine transform (DCT), and behind dct transform dateout; An electronic watermark data extracts position table 205, the information of the position that each class in its storage representation n electron-like watermark data is taken out from image block; And a tables of data that is extracted 206, the data that the n class of the whole screen of its storage is extracted; One electronic watermark data table 208, its storage n electron-like watermark data; One electronic watermark data withdrawal device 204, it is according to extracting electronic watermark data by the positional information of DCT transducer 203 output from the frequency data by the j * k pixel of DCT transducer 203 outputs, and stores the electronic watermark data that extracts in the extracted data table 206 precalculated position; And an electronic watermark data detector 207, its from electronic watermark data table 208 and the tables of data that is extracted 206 extract m data (m=1,2,3 ... n), and calculating is extracted the statistics similitude of data and electronic watermark data.
In the present invention, the content of the electronic watermark data position of electronic watermark data table and respective number table must be in the side of insertioning and detection side's unanimity each other.Also promptly, insert and m of the detection side (m=1,2,3 ... n) content corresponding of electronic watermark data table must correspond to each other.In addition, the content of inserting the electronic watermark data insertion position table 105 of device side must extract the content of position table 205 with the electronic watermark data of checkout gear side also must be consistent.
With reference to figure 1, will the operation that electronic watermark data inserts device be described.
Dct transform device 103 takes out from original image and is of a size of the blocks of data 102 of 8 * 8 pixels to carry out dct transform.Electronic watermark data inserter 104 takes out a plurality of electronic watermark datas that will be inserted into from the table 105 of electronic watermark data insertion position on the basis of the position data of the piece of being exported by dct transform device 103.Then, electronic watermark data inserter 104 takes out the electronic watermark data that numeral equates with the numeral of being taken out by electronic watermark data insertion position table 105 from electronic watermark data table 106, so that electronic watermark data is inserted by in the data behind the dct transform of dct transform device 103 outputs.
107 pairs of data by 104 outputs of electronic watermark data inserter of idct transform device are carried out idct transform, and depositing data in same position 109, this position is identical with dct transform device 103 has taken out blocks of data in will inserting the image memory block 108 of data position.
All pieces by table 105 appointment of electronic watermark data insertion position are carried out operation recited above.In addition, directly do not copied in the memory by the raw image data 101 of electronic watermark data insertion position table appointment in the piece, this memory is temporarily by unshowned processing path storing image data 108 among Fig. 1.
Then, with reference to figure 2, will the operation of electronic watermark data checkout gear be described.
The all pieces that extracted position table 205 appointment by electronic watermark data are carried out above-mentioned operation.
After the extracted data of a screen is stored into extracted data memory block 206, electronic watermark data detector 207 from the extracted data memory block and electronic watermark data table 208 take out data and the electronic watermark data be extracted accordingly, and the counting statistics similarity degree is with the output result.
When n electron-like watermark data, electronic watermark data detector 207 repeats n above-mentioned operation, and calculates all electronic watermark datas and be extracted the statistics similarity degree of data, to export result 209.
Fig. 3 is the schematic diagram of electronic watermark data insertion position table, the position that insertion position each electronic watermark data of table expression wherein is inserted into and the value of the table of the detection position when inserting four electron-like watermark datas.The view data of whole screen is split into the piece that is of a size of the j * k shown in Fig. 3, and deposits the ordinal number of expression for the electronic watermark data that will insert of each piece in.
The example of Fig. 3 points out, when the upper left side of image is set to original value, row number be 1 and row number be to insert first electronic watermark data in 1 the piece, insert second electronic watermark data in the piece of a piece of displacement in the horizontal direction.
Referring to figs. 1 to Fig. 3, will the operation that electronic watermark data inserts device be described more specifically.
Dct transform device 103 number all is that the blocks of data 102 that is of a size of j * k is taken out in 1 position from the row of original image No. 101 and row, carries out dct transform, and behind dct transform the data of output expression row and column number and frequency data.It is 1 electronic watermark data that electronic watermark data inserter 104 takes out the label that will insert from electronic watermark data insertion position table 105 on by the basis of the position data of the row of the piece of dct transform device 103 output number 1 and row number 1.
Then, it is corresponding first electronic watermark data of electronic watermark data of 1 that electronic watermark data inserter 104 takes out with label from electronic watermark data table 106, and first electronic watermark data is inserted by in the frequency data behind the dct transform of dct transform device 103 outputs.107 pairs of data by 104 outputs of electronic watermark data inserter of idct transform device are carried out idct transform, and to deposit data in row number and row number all be 1 position, this position is identical with the dct transform device has extracted data from zone 108 position, deposits the image that is inserted into electronic watermark data in zone 108.
Then, number all be that 1 blocks of data carries out similar operation to row number and row.All pieces by table 105 appointment of electronic watermark data insertion position are carried out above-mentioned operation (in the example of Fig. 3, at all data in the view data).
Then, with reference to figure 2 and Fig. 3, will the operation of electronic watermark data checkout gear be described more specifically.
Then, electronic watermark data withdrawal device 204 extracts electronic watermark data from the frequency data that carry out behind the dct transform by dct transform device 203 output, and it is deposited in corresponding to first of the electronic watermark data of the label in the extracted data storage area 206 1 extracts the district.
Then, number all be that 1 blocks of data is similarly handled to row number and row.All blocks of data that extracted position table appointment by electronic watermark data are carried out above-mentioned operation (in the example of Fig. 3, being at all pieces in the view data).
After the extracted data that will put in order screen deposits the extracted data memory block in, 206 taking-ups, first extracted data reach from electronic watermark data table 208 taking-up first electronic watermark data electronic watermark data detector 207 from the extracted data memory block, and the counting statistics similarity degree is with the output result.
Then, 206 taking-ups, second extracted data reach from electronic watermark data table 208 taking-up second electronic watermark data electronic watermark data detector 207 from the extracted data memory block, and the counting statistics similarity degree is with the output result.
By similar mode, equally the 3rd extracted data and the 3rd electronic watermark data and the 4th extracted data and quadrielectron watermark data are similarly handled.
As mentioned above, the present invention is the block unit of j * k pixel with an image segmentation, and changes the electronic watermark data that will insert of each piece, thereby, when inserting a plurality of electronic watermark datas in the image, can prevent the problem of a plurality of electronic watermark data phase mutual interference.
For those of skill in the art, to various change that the present invention made and revise all in by claims institute restricted portion.
Claims (2)
1. one kind is inserted device in the digital picture with electronic watermark data, it is characterized in that comprising:
A quadrature transformer, it takes out the image block that is of a size of j * k from digital picture, and wherein j and k are natural number, and described image block is carried out orthogonal transform, and the positional information of the image block of output taking-up and the data after the orthogonal transform;
An electronic watermark data extracts the position table, the positional information that each class of the electronic watermark data of its storage representation n class is taken out from image block, and wherein n is a positive integer;
An extracted data table, the image block data that comprises n electron-like watermark data of the whole screen of its storage;
One electronic watermark data table, its storage n electron-like watermark data;
One electronic watermark data withdrawal device, it extracts the position according to the positional information by described quadrature converter output from described electronic watermark data and show the positional information that each class of the electronic watermark data of extraction expression n class is taken out from image block, extract the frequency data that comprise electronic watermark data from frequency data by the piece of described quadrature transformer output, and storing frequency data in the described extracted data table precalculated position, described extracted data table is consistent with the electronic watermark data number of taking-up;
And an electronic watermark data detector, it extracts m data from described electronic watermark data table and described extracted data table, m=1 wherein, and 2,3 ... n, and calculating is extracted the statistical approximation of data and electronic watermark data.
2. method that detects the electronic watermark data in the digital picture is characterized in that comprising following steps:
Prepare electronic watermark data in advance and extract the position table, the view data that its record will comprise n electron-like watermark data is of a size of the position of taking out in the piece of j * k pixel from image, wherein j and k are natural number, and the electronic watermark data table, its storage n electron-like watermark data;
Take out image block from digital picture, carry out orthogonal transform, and obtain the image block of taking-up and the positional information of the data after the orthogonal transform;
On the basis of described positional information, extract position table taking-up and represent the positional information that each class of the electronic watermark data of n class is taken out from image block from described electronic watermark data, take out the frequency data that comprise electronic watermark data from frequency data, and will the described frequency data that comprise electronic watermark data store into and extract the precalculated position that the position is shown with the corresponding to electronic watermark data of the electronic watermark data number that is taken out by the piece of described quadrature transformer output;
Extract the position table from described electronic watermark data table and described electronic watermark data and take out m data, m=1 wherein, 2 ... n, and the data that are extracted of calculating and the statistics similarity degree of electronic watermark data; And
Each of a described n electronic watermark data is estimated the size of this statistics similarity degree.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 02156019 CN1207892C (en) | 2002-12-11 | 2002-12-11 | Method and device for inserting digital image into electronic water-print and detecting method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 02156019 CN1207892C (en) | 2002-12-11 | 2002-12-11 | Method and device for inserting digital image into electronic water-print and detecting method |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN99100376A Division CN1113355C (en) | 1999-01-19 | 1999-01-26 | Method and device for inserting electronic watermark into digital image and testing electronic watermark |
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| CN1441593A CN1441593A (en) | 2003-09-10 |
| CN1207892C true CN1207892C (en) | 2005-06-22 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US7636440B2 (en) * | 2003-01-31 | 2009-12-22 | Hewlett-Packard Development Company, L.P. | Digital watermark with variable location |
| CN101258743B (en) * | 2005-09-08 | 2010-07-14 | 汤姆森许可贸易公司 | Digital cinema projector watermarking system and method |
| JP4965996B2 (en) * | 2006-12-22 | 2012-07-04 | キヤノン株式会社 | Image processing apparatus, image processing method, image processing program, and storage medium |
| DE102008014311A1 (en) * | 2008-03-14 | 2009-09-17 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | An embedder for embedding a watermark in an information representation, a detector for detecting a watermark in an information representation, method, computer program and information signal |
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