一种稳健的基于小波变换的彩色图像数字水印算法Word文件下载.docx

1、paper, A robust wavelet-based color image digital watermarking scheme is proposed. Theproposed digital watermark is a random real number of a sequence of bits embedding intolow frequency of Green component sub-band. The embedding method is based on threelevels Discrete Wavelet Transform （DWT） low co

2、efficient. A threshold is used togenerate frequency of watermarks with the compare of created frequency of DWT inembedding position. Experimental results showed that the embedded watermark is robustagainst various signal processing and compression attacks such as Salt & pepper noiseaddition, Croppin

3、g, Scaling, JPEG compression, Mean filtering, Copying and pasting andso on.Keywords: Digital watermarking, wavelet transform, Color image, Green component,Low frequency and Robustness, information hiding.3List of FiguresFigure 2.1 0.1 Schematic description of steganography.5Figure: 2.2 Communication

4、 channel for cryptosystem7Figure 2.3 Monograms figuring TGE RG.8Figure 2.4 Generic digital watermarking scheme 11Figure 2.5 Generic digital watermarking decoder .11Figure 2.6 Generic digital watermarking scheme 13Figure 2.7 Basic watermark embedding scheme .14Figure 2.8 Basic watermarking Decoding s

5、ystem15Figure 2.9 Classification of watermarking algorithms based on domain used for thewatermarking embedding process .16Figure 2.10 Classification of watermarking based on applications .17Figure 2.11 Digital watermarking requirements triangle 20Figure 3.1 Watermarks in Mark and Dollar bank notes .

6、24Figure 3.2 Visible watermark.24Figure 3.3 Invisible watermark 25Figure 3.4 Delivering Digital data to a trusted End system.26Figure 3.5 Delivering Digital data to the customer26Figure 3.6 Conflict: Alice and Bob can both detect their respective watermark in imageI28Figure 3.7 Image Lena Copying or

7、 distributing in print or electronic forms withoutwritten permission31Figure 3.8 The embedding scheme of the watermarking algorithm as proposed by Cox etal. A lot of the proposed watermarking techniques share the same model.36Figure 3.9 The wavelet pyramid of three-level image decomposition. Each le

8、vel consistsof three detail images, which correspond to horizontal, vertical, and diagonal details ofeach resolution level. xy stands for applying filter x in row direction and filter y in columndirection, where L means low-pass filtering, H high-pass filtering, and C is the coarseimage .384Figure 4

9、.1 DWT three level decomposition flow chat of a color image.40Figure 4.2 Watermark Embedding Algorithm flowchart 42Figure 4.3 Watermark Extraction Algorithm flowchart .44Figure 4.4 Invisibility Experiment （a） Original Image （b） Watermarked Image.45Figure 4.5 Watermarked Image Suffering various kinds

10、 of attacks （a, b, c, d）.455List of TableTable 2.1 Number of publications on digital watermarking during the past few yearsaccording to Watermarking world .org .15Table 2.2 Number of publications on digital watermarking during the past few yearsaccording to INSPEC, Jan, 1999. .15Table 4.1 The Detect

11、ion response between the extracted watermarks and the attackedwatermarked image under different types of attacks 46IVHunan UniversityStatement of OriginalityI hereby certify that the thesis submitted is based on the research carried out by myselfindependently under the guidance and supervision of my

12、 supervisor. Any ideas orquotations from the work of other individual and collective works are fully acknowledgedin accordance with the standard referencing practices of the discipline.Authors Signature: Date: -May , 28, 2007Copyright StatementPermission is herewith granted to Hunan University to ci

13、rculate and to have copied fornon-commercial purposes, at its discretion, this thesis upon the request of individuals orinstitutions. The author does not reserve other publication rights and the thesis nor mayextensive extracts from it be printed or otherwise reproduced without the authors writtenpe

14、rmission.This thesis belongs to:1. Secure , and this power of attorney is valid after _.2. Not Secure（Please mark the above corresponding check box） May,_,2007Supervisor May, _,20071Chapter 1 Introduction1.1 PreambleIn recent years, the development of the Internet and multimedia technology, it is ea

15、sier toproduce, distribute, acquire and copy digital media products such as digital text, image,video and audio 1. That is why, it is necessary to protect the digital production. Thedigital watermarking technique can solve the problem. The digital watermark which isrepresents the ownership of the ow

16、ner according to the embedding information into theoriginal image. It can be applied to different applications including digital signatures,fingerprinting, broadcast and publication monitoring, authentication, copy control andsecret communication 2. Usually, an effective digital watermark scheme pro

17、vides thethree major properties 3. （i）Imperceptibility （ii） Robustness and （iii） Un ambiguity. Theembedded watermarking must be imperceptibility and invisible because of two primaryconcerns; firstly we should not lower the quality of the original image or it will the breakthe aesthetic feeling and d

18、iminish the commercial value of the original. Second, if thewatermark embedded is detected by hacker, it will be easily broke or be removed.Watermarked image should be robust. The watermark could still be extracted clearly aftersome digital image processing such as lossy or lossless image compressio

19、n. In thewatermark extraction process, it should be unambiguous to prove the ownership of theowner 3. One of the primary watermarking designing considerations is that theinvisibility and robustness often collide 4. In order to improve the robustness of thewatermarking scheme, we must embed more and

20、more watermark information andtherefore cause the quality of the image lower and lower. It seems like that the originalimage has been interfered with much more noise. On the other hand, in order to keep thequality of the original image, we embed fewer information and high robust ofwatermarking schem

21、e. Usually, there are two kinds of basic watermarking design scheme45, （1） Spatial domain and （2） Transform domain or Frequency domain （ DCT, DWT,DFT）. The watermark is more robust in the frequency domain than in the spatial domain.So the method we choose frequency domain to embed the watermark. The

22、re are many2researches and develops have been done grayscale image but the color image is notsufficient. Now a day color image is dominant most of the parts of applications.Embedding information in color image RGB color channel is highly correlated so it is notsuitable for embedding watermark. Some

23、proposed embedding schemes focus onembedding watermarks in the Y component （luminance） in YIQ model. Kutter et al 6embed the watermark by modifying selected set pixels in the blue channel because of itslow sensitivity to human perception. The blue channel is the best choose to JPEGcompression among

24、the RGB because of its low sensitivity to human perception. So thehidden watermark is easy to be lost. Red Channel embedding watermark problem is itsvery large energy loss. During the RGB true color image compressed into JEPG, theembedding watermark in the red channel is easy to lost and difficult t

25、o extract. Otherwisegreen channel can endure JEPG compression and the embedded watermark is robustenough. So our select is Green channel to embed watermark information to examine itscapability.1.2 MotivationModern age is the age of digital technologies. The digital information exchange like asIntern

26、et and multimedia technology becomes easier to produce, distribute, modify,acquire and copy digital media products such as digital text, image, video and audio. Butthese results create serious problem because unauthorized copying and modification ofthe context. Any one can easily copy the digital pr

27、oducts from internet and it becomesvery easy to get benefit from it without owner permission. Even they can claim that theyare the owners of the copyright.For this reason piracy becomes great threat for innovation and business. In order to solveintellectual property problems of the digital age, the owner have the protecti