CN101136104A - Self-adapting multiple domains watermark method - Google Patents
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- CN101136104A CN101136104A CNA2007101636739A CN200710163673A CN101136104A CN 101136104 A CN101136104 A CN 101136104A CN A2007101636739 A CNA2007101636739 A CN A2007101636739A CN 200710163673 A CN200710163673 A CN 200710163673A CN 101136104 A CN101136104 A CN 101136104A
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Abstract
In the currently-used watermark technology, the watermark information always is embedded into the transform domain, and a human sensible model established in the domain is used to adjust the embedded strength of the watermark; checking the watermark must be made in the transform domain such that it makes against designing an anti geometry attack policy. The invention embeds watermark into the transform domain, and adjusts the watermark embedded strength at space domain; by using the combination of the features of two domains, a balance between the robustness and the un-sensible ability can be obtained.
Description
Technical field
The invention belongs to the digital watermark technology field, be specifically related to a kind of adaptive multiple domains watermark method
Background technology
Past 10 years, the use of digital media information and distribution explosive increase.By the internet, people can issue and obtain various numerical informations easily, comprise image, audio frequency, video and text etc., and many online services.But simultaneously, piracy also becomes and is more prone to, and unrestricted duplicating makes digital content have no copyright with uncontrollable transmission can to say.Management and protection to digital content become the problem that industry presses for solution.
Digital watermarking is a kind of emerging copyright protection technology.How its research hide a certain amount of additional information in original media data, the sign of the entitlement of works, the right to use or company etc. for example, and the purpose by the extraction that is hidden information and identification are reached the checking copyright.Here, original media data is the carrier of watermark information, can be described as carrier signal, and information embeds the index word of introducing and can be described as watermark signal.A good digital watermarking system should satisfy two important requirements: not sentience and robustness.Described not sentience is meant that variation that embed watermark causes media quality should be ND to observer's vision system, optimal situation is to add the medium of watermark and original media visually the same (also is same requirement to the sense of hearing), this be most watermarking algorithms the requirement that should reach.Described robustness is meant that a digital watermarking should be able to be born a large amount of, different physics and geometric distortion, comprises (as the malicious attack) had a mind to or (as compression of images, filtering, scanning and duplicating, noise pollution, change in size or the like) unintentionally.Yet the two is conflicting.How when improving robustness, to guarantee can not cause the tangible distortion of signal to fail to obtain good solution always.
In the past, use various signal quality estimation methods to measure the carrier signal of embed watermark and the amount distortion between the initial carrier signal in the data waterprint embedded method, commonly used have square error, signal to noise ratio (S/N ratio), Y-PSNR and various sensor models etc., and in view of the above watermark strength is adjusted the not sentience that obtains watermark.Typical perception shaping watermark (C.I.Podilchuk et al..Image-adaptive watermarking usingvisual models.IEEE J.Selected Areas Communications, May 1998,16 (4): 525-539) with maximum not obvious index word (the Just noticeable differences of each component of initial carrier signal, JND ' s) is weight weighting watermark signal, makes the watermark signal after the shaping meet people's sensory perceptual system feature.The amount distortion that it uses the quality indicator metrics watermark of an overall situation to cause, thereby the watermark strength that draws an overall situation is adjusted the factor.
Liu Jiufen etc. have proposed a kind of simple wavelet field water mark method (referenced patent CN02115174.1).This method uses simple linear modulation that watermark is embedded into the low frequency range of carrier signal, and an overall stretching factor is used to control the embedment strength of watermark.
Tian Li etc. have designed a kind of image watermark method (seeing patent CN01114581.1).It carries out layering, piecemeal to carrier image earlier, selects image block then at random and is embedded in watermark in integral discrete cosine transform (DCT:DiscreteCosine Transform) territory.This method can be avoided error that signal transformation brings and the security that has improved watermark.
G F.G De Boweilei etc. has invented a kind of method and apparatus (seeing patent CN01806071.4) that is used at the information signal embed watermark.It utilizes the data of original vector signal to determine the local weighted factor of watermark signal, so that basically can not perception after watermark signal after the shaping and the original signal stack.This thought is similar to perception shaping watermark, and local weighted factor is corresponding each component of signal.
Guo Baolong etc. have proposed a kind of wavelet field digital watermark method based on image target area (seeing patent CN03134437.2).It carries out wavelet transformation to the initial carrier image earlier, and utilizes the variance of wavelet coefficient to determine sensation target zone and background; Then, utilize the quantification modulation that watermark signal is embedded on the corresponding high frequency wavelet coefficient block in sensation target zone.
Rock paddy Thailand knows etc. and to have designed a kind of apparatus and method (seeing patent CN200510009072.3) that are used for embedding with the detected image digital watermarking.It is divided into a plurality of topographies to piece image, and embeds a digital watermarking in each topography.In order to guarantee the watermark invisibility, they only revise least significant bit (LSB) or two minimum significance bits.
Known digital watermark is always selected embedded location in some territories of carrier signal, and adjusts the watermark strength on each embedded location, detects watermark and also carries out in same territory.If with the spatial domain is to embed the territory, then the robustness of watermark is not good, thereby is to embed the territory usually with the transform domain.But the embedment strength of adjusting watermark in transform domain is not direct, destroy the perceived quality of low frequency range signal easily, and the general more complicated of sensor model in the transform domain, increased the calculated amount of watermark embed process greatly, also needing of having made piecemeal to original signal and handles and more can cause block effect.In transform domain, carry out watermark detection and be unfavorable for designing the watermark strategy of resisting geometric attack.
Summary of the invention
At the defective that exists in the prior art, the purpose of this invention is to provide a kind of adaptive multiple domains watermark method, this method is united the feature of using a plurality of territories can be at watermark robustness and do not obtain good compromise effect between the sentience, and watermark detection can be carried out in a plurality of territories simultaneously.
For reaching above purpose, the technical solution used in the present invention is: a kind of adaptive multiple domains watermark method, it is embedded in watermark at the transform domain of carrier signal, but adjusts watermark embed strength in the original domain of carrier signal.Specifically may further comprise the steps:
(1) embedded location of selection watermark in transform domain.
(2) produce original watermark template signal.
(3) the watermark template signal is carried out inverse transformation.
(4) the index word embed watermark signal at each component place of adjustment carrier signal.
Further, original domain is meant the territory at the current place of signal, for example spatial domain, time domain, and transform domain is meant the territory of carrier signal being implemented signal place after a kind of conversion, for example discrete cosine transform domain, Discrete Fourier Transform territory, wavelet transformed domain etc.But original domain is relative with transform domain, and when carrier signal was exactly a signal in the transform domain originally, the so above-mentioned original domain of saying just became transform domain, and transform domain is exactly an original domain.
Further, describedly be transformed to orthogonal transformation.
Further again, in the step (1), embedded location is chosen in the transform domain human perception system and common signal is handled all insensitive zone of operation.
Further again, in the step (2), produce one group of random number sequence isometric, and the random number that produces is placed on the watermark embedded location according to the order of sequence with embedded location, other positions get zero, generate the watermark template signal.
Further again, the described global change that is transformed to.
Further again, in the step (4), the adjustment strategy of watermark embed strength should guarantee that the signal height before watermark signal and the shaping after the shaping is relevant.
Further again, in the step (4), according to the corresponding watermark embed strength of coverage intensity adjustment of each component of carrier signal.
Further again, in the step (4), select the further index word of adjusting each component of carrier signal of gain factor of an overall situation according to embedding distortion condition, the embedding distortion condition is satisfied.
Further, when the conversion of using was not orthogonal transformation, the watermark template signal that produces in the step (2) must satisfy in perception shaping front and back still height correlation.
Effect of the present invention is: adopt method of the present invention, embed device by selecting embedded location and using the perception shaping policy to help the robustness that obtains to improve and good not sentience; Watermark detection can be carried out in a plurality of territories, the strategy of opposing geometric attack easy to use; Because watermark embed process only uses an inverse transformation, embedding calculated amount can significantly reduce.
Description of drawings
The basic framework of the adaptive multiple domains watermark method of Fig. 1.
The basic process of embed watermark among Fig. 2 embodiment.
Fig. 3 original image (left side), add watermark image (in) and the Error Graph between the two (having amplified 10 times) (right side).
The change curve of the relative JPEG compression quality of Fig. 4 ELC factor.
Watermark figure (noise grade is 30) after Fig. 5 additive noise is attacked.
The change curve of Fig. 6 ELC relative noise attack strength.
Watermark figure (filter scale is 5) after Fig. 7 Median cut wave filter is attacked.
The change curve of the relative Median cut of Fig. 8 ELC wave filter yardstick.
The change curve of Fig. 9 ELC relative shear ratio.
The change curve of Figure 10 ELC relative scale pantograph ratio.
The change curve of Figure 11 ELC relative rotation angle.
Embodiment
Describe a specific embodiment of the present invention below in conjunction with accompanying drawing 2, and further specify effect of the present invention.
Embodiment:
To be of a size of the picture signal f (n of M * N
1, n
2) be carrier signal, realize a kind of adaptive multiple domains watermark method, whole process may further comprise the steps as shown in Figure 2:
(1) embedded location of selection watermark in DCT.
Select L intermediate frequency coefficient point as the watermark embedded location at random.
(2) generate original watermark template signal W (k
1, k
2).
Utilize key K to generate one as the seed of random number generator and longly be the random number sequence of L, wherein each element meets the separate standards Gaussian distribution.The random number that produces is come on the watermark embedded location according to the order of sequence, and other positions get zero, forms one with the big or small identical two-dimensional sequence of former figure, just W (k
1, k
2).
(3) to W (k
1, k
2) carry out inverse DCT and obtain sequence w (n
1, n
2).
(4) the coverage intensity a (n at each picture element place of calculating in spatial domain
1, n
2).
Draw the local standard difference σ (n at each picture element place earlier
1, n
2), right back-pushed-type a (n
1, n
2)=a σ (n
1, n
2) calculate and cover intensity, wherein α is that overall embedment strength is adjusted the factor, the distortion condition that utilizes signal to noise ratio (S/N ratio) to describe is determined.
(5) revise original image signal and embed signal.
Utilize sequence a (n
1, n
2) weighting shaping watermark signal w (n
1, n
2), generate the image f that contains watermark on each picture element of the original image that then watermark signal after the shaping is added to
w(n
1, n
2), promptly
f
w(n
1，n
2)＝f(n
1，n
2)+aσ(n
1，n
2)w(n
1，n
2)
In order to show remarkable result of the present invention, present embodiment provides some experimental results of utilizing embodiment to draw.Carrier signal is got " Lena " figure of 512 * 512.Press the Zig-Zag order with the interval (| 512 * 512/3|, | 512 * 512 * 2/3|) are decided to be intermediate frequency zone, and count from the starting point of intermediate frequency zone and to get L=1024 Frequency point as the watermark embedded location.From left to right provided original image among Fig. 3 respectively, contained the image of watermark and the absolute error figure between them, the signal to noise ratio (S/N ratio) of wherein preceding two width of cloth figure is 36dB, and Error Graph has been exaggerated 10 times.Clearly, the image and the original image that have added watermark are just the same, are impossible distinguish them from naked eyes.It is fine that watermark signal is hidden, so could obtain not sentience of very desirable watermark.On Error Graph, can more be clear that the coverage effect.The energy of watermark signal is shaped to the texture region and the submarginal zone of image really, and the smooth region of image is modified seldom.Watermark embeds the local feature that has fully used image.Why obtain these superior performances and give the credit to the shaping policy that we propose, watermark just is embedded into the midband of image and utilizes spatial domain to cover model further to the watermark signal shaping.This strategy has the advantage of several respects than forefathers' work: 1) use the DCT of the overall situation to avoid block effect.2) our method can keep the perceived quality in image smoothing zone as much as possible, because our shaping and utilized image local variance information in spatial domain.On the contrary, use the human sensor model embed watermark that designs in the transform domain, along with the increase of embedment strength, the image quality distortion of smooth region is serious, and its reason is the quality of these models estimated image in transform domain, and is fundamentally different with the people.Perhaps, they are the quality of evaluate image details area well, but but very undesirable to the smooth region of image.3) our method has not only been used the feature of spatial domain but also has been used the feature of frequency field, and this makes its performance surpass the human sensor model of existing spatial domain.
Algorithm complex is another important digital watermarking attribute.For " Lena " figure that is of a size of 512 * 512, on average the embedding time is 1413 milliseconds, and the average detected time is 865 milliseconds.And when the reducing of picture size, they also significantly reduce thereupon.Compare with general transform domain watermarking algorithm, our method is approximately saved the time of half, and reason is only to have used inverse DCT in telescopiny one time.Certainly, our method spends more time possibly than those simple algorithms based on spatial domain, yet it still is applicable to the application demand that some are real-time.
Assess the robustness of watermark below.All tests all are to carry out on the Stirmark4 platform.The watermarking images quality that adds that is used to test is 36dB.What detecting device adopted is linear dependence (LC:linear correlation) detecting device, extracts the threshold value that watermark uses and is τ=2.72, is that to warn rate in mistake be 10
-6Condition under calculate.Threshold value can be normalized to zero by from LC, deducting threshold tau, this difference LC-τ can be described as effective LC (Effective LC, ELC).Here only having provided in size is that 512 * 512 standard " Lena " goes up the experimental result that obtains, but similar result can obtain on other standard picture.
At first, add watermarking images and passed through one group of different quality factor (Quality Factor, JPEG compression attack QF).Fig. 4 change curve of ELC that drawn with QF.Fig. 4 shows that our method is suitable robust, even to resist quality factor be 5 JPEG compression.
Then, will add watermarking images attacks through the additive noise of varying strength.Fig. 5 has shown the watermarking images (intensity is 30) after a width of cloth is attacked.Fig. 6 change curve of ELC that drawn with attack strength.Even we see that for very strong attack (as shown in Figure 5), the output valve LC of detecting device is still very high.This illustrates that it is very robust that our scheme is attacked additive noise.
Now, will add watermarking images by Median cut wave filter.Fig. 7 has provided a filtered image.Fig. 8 change curve of ELC that drawn with filter size.As can be seen, the scheme of proposition is responsive relatively to filtering, but watermark can be resisted significant distortion (as Fig. 7).
Below the test watermark is to the robustness of several geometric attacks.Geometric attack has not only caused the watermark information loss, and main is to cause the synchronizing information loss, and this is the current the most difficult problem that faces of digital watermark.At present, existing many kinds of synchronization scenarios are used for head it off.Herein, we adopt a kind of simple realization, promptly watermark normalization and thoroughly the technology of searching combine and overcome geometric attack, the standard size of wherein supposing the watermark template signal is 512 * 512.
Test the robustness of watermark first to shearing attack.In this group test, watermarking images is attacked by large-scale shearing ratio.Watermark detection is carried out in spatial domain.Image after shearing is slided on the standard watermark signal templates to search for maximum LC.The change curve of the ELC relative shear ratio that Fig. 9 has drawn maximum.Erect image we find out like that, the method for proposition is robust very, watermark even can resist shearing attack more than 30%.
The geometric attack that another kind is used to test is a scale.The variation range of zoom factor γ from 25% to 200%.Do not need to search for zoom factor, the image zoom after only needing will attack before detecting watermark is that standard scale gets final product.Figure 10 has provided the change curve of the relative zoom factor of ELC.Obviously, our method is attacked very robust to this type of.At γ〉1 o'clock, the variation of LC is quite steady, and γ＜1 o'clock also can be resisted the scale of ratio 30% and be attacked.
To a series of rotary manipulations of the fulfillment that adds watermark, the anglec of rotation is from 0 ° to 365 ° again.When detecting watermark, the angle of image rotation after attacking, calculate LC more earlier.If postrotational image is different with the size of watermark masterplate signal, then need to use the slip correlation detector.For obtaining maximum LC, need the whole angular region of search.Figure 11 has provided the change curve of ELC relative rotation angle.As shown in the figure, our method is attacked rotation and has been showed very strong robustness, and the rotation that can resist in the whole angular range is attacked.What is interesting is that more LC has periodically with the variation of angle, the cycle is a pi/2.The chances are because the information loss that rotation θ and θ+pi/2 is introduced is roughly the same.
The experimental result that present embodiment obtains can illustrate, uses method of the present invention not only to realize not sentience of optimum watermark part, and the robustness of watermark has also obtained significantly promoting.
Present embodiment has provided the implementation result of image watermark, handles but the invention is not restricted to image watermark, and the present invention is equally applicable to multimedia digital watermark processing such as digital music, video.
The present invention can implement with other concrete form, and does not break away from its spirit or essential characteristic.It only is illustrative and nonrestrictive that described embodiment is considered in all respects, for example:
1) the carrier signal type is not limited to image, audio frequency and video etc.;
2) embedded location is not limited to intermediate frequency zone;
3) generation of watermark signal is not limited to only utilize key information;
4) watermark signal is not limited to use the random number of normal distribution;
5) employed conversion is not limited to DCT, Fourier conversion and wavelet field etc.;
6) perceived quality is measured and is not limited to use signal to noise ratio (S/N ratio), Watson vision mode;
7) selection of watermark imbedding function, watermark signal shaping policy and various parameters etc.Therefore, scope of the present invention by appended claims but not foregoing description indicate.Falling into the meaning of equivalence techniques scheme of claim and all changes of scope is included among its scope.
Claims (10)
1. adaptive multiple domains watermark method, it is embedded in watermark at the transform domain of carrier signal, but adjusts watermark embed strength in the original domain of carrier signal.Specifically may further comprise the steps:
(1) embedded location of selection watermark in transform domain.
(2) produce original watermark template signal.
(3) the watermark template signal is carried out inverse transformation.
(4) the index word embed watermark signal at each component place of adjustment carrier signal.
2. a kind of adaptive multiple domains watermark method as claimed in claim 1, it is characterized in that: original domain is meant the territory at the current place of signal, for example spatial domain, time domain, and transform domain is meant the territory of carrier signal being implemented signal place after a kind of conversion, for example discrete cosine transform domain, Discrete Fourier Transform territory, wavelet transformed domain etc.But original domain is relative with transform domain, and when carrier signal was exactly a signal in the transform domain originally, the so above-mentioned original domain of saying just became transform domain, and transform domain is exactly an original domain.
3. a kind of adaptive multiple domains watermark method as claimed in claim 2 is characterized in that: describedly be transformed to orthogonal transformation.
4. a kind of adaptive multiple domains watermark method as claimed in claim 3 is characterized in that: in the step (1), embedded location is chosen in the transform domain human perception system and common signal is handled all insensitive zone of operation.
5. a kind of adaptive multiple domains watermark method as claimed in claim 3, it is characterized in that: in the step (2), produce one group of random number sequence isometric, and the random number that produces is placed on the watermark embedded location according to the order of sequence with embedded location, other positions get zero, generate the watermark template signal.
6. a kind of adaptive multiple domains watermark method as claimed in claim 3 is characterized in that: in the step (3), and the described global change that is transformed to.
7. a kind of adaptive multiple domains watermark method as claimed in claim 3 is characterized in that: in the step (4), the adjustment strategy of watermark embed strength should guarantee that the signal height before watermark signal and the shaping after the shaping is relevant.
8. a kind of adaptive multiple domains watermark method as claimed in claim 7 is characterized in that: in the step (4), according to the corresponding watermark embed strength of coverage intensity adjustment of each component of carrier signal.
9. a kind of adaptive multiple domains watermark method as claimed in claim 8, it is characterized in that: in the step (4), select the further index word of adjusting each component of carrier signal of gain factor of an overall situation according to embedding distortion condition, the embedding distortion condition is satisfied.
10. a kind of adaptive multiple domains watermark method as claimed in claim 1 is characterized in that: when the conversion of using in the step (1) was not orthogonal transformation, the watermark template signal that produces in the step (2) must satisfy in perception shaping front and back still height correlation.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102467636A (en) * | 2010-11-05 | 2012-05-23 | 优硕资讯科技股份有限公司 | Device and system for making watermark on file with self-selected and self-defined contents |
| CN104486627A (en) * | 2014-12-23 | 2015-04-01 | 成都索贝数码科技股份有限公司 | Method for embedding, detecting and extracting digital watermarks |
| CN108876697A (en) * | 2018-06-22 | 2018-11-23 | 南开大学 | Pixel-level image certification, tampering detection and restoration methods |
| CN109242793A (en) * | 2018-08-29 | 2019-01-18 | Oppo广东移动通信有限公司 | Image processing method, image processing device, computer-readable storage medium and electronic equipment |
| CN109309869A (en) * | 2018-09-11 | 2019-02-05 | 东方网力科技股份有限公司 | A kind of watermark embedding method, device and storage medium |
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2007
- 2007-10-18 CN CNA2007101636739A patent/CN101136104A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102467636A (en) * | 2010-11-05 | 2012-05-23 | 优硕资讯科技股份有限公司 | Device and system for making watermark on file with self-selected and self-defined contents |
| CN104486627A (en) * | 2014-12-23 | 2015-04-01 | 成都索贝数码科技股份有限公司 | Method for embedding, detecting and extracting digital watermarks |
| CN104486627B (en) * | 2014-12-23 | 2017-07-28 | 成都华栖云科技有限公司 | A kind of embedding algorithm, detection and extracting method |
| CN108876697A (en) * | 2018-06-22 | 2018-11-23 | 南开大学 | Pixel-level image certification, tampering detection and restoration methods |
| CN108876697B (en) * | 2018-06-22 | 2022-02-25 | 南开大学 | Pixel-level image authentication, tampering detection and recovery method |
| CN109242793A (en) * | 2018-08-29 | 2019-01-18 | Oppo广东移动通信有限公司 | Image processing method, image processing device, computer-readable storage medium and electronic equipment |
| CN109309869A (en) * | 2018-09-11 | 2019-02-05 | 东方网力科技股份有限公司 | A kind of watermark embedding method, device and storage medium |
| CN109309869B (en) * | 2018-09-11 | 2021-01-26 | 东方网力科技股份有限公司 | Watermark embedding method, device and storage medium |
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