一种稳健的基于小波变换的彩色图像数字水印算法(完整版)实用资料.doc

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1、一种稳健的基于小波变换的彩色图像数字水印算法（完整版）实用资料(可以直接使用，可编辑 完整版实用资料，欢迎下载）IABSTRACTThe revolution of the digital information has brought big changes in our lives and our society. The digital information has also generated new challenges and new opportunities for innovation. This thesis discusses the issues regarding

2、information hiding in the digital image and its application for secure the digital multimedia, addressing both theoretical and practical aspects and tacking both design and attack problems. In the fundamental part, we discuss the key elements of watermarking and its application in digital image. In

3、the design part, we present new information hiding algorithm for digital color image. The design provides concrete examples regarding the choice of embedding and extraction mechanisms. With the growth of networked multimedia systems, the need of securecommunication and data transfer go increasingly.

4、 Applications are numerous and various like satellite or medical imagery, or remote monitoring. During images transfer, data integrity is not really secure. Watermarking can be an answer to such problems. In this paper, A robust wavelet-based color image digital watermarking scheme is proposed. The

5、proposed digital watermark is a random real number of a sequence of bits embedding into low frequency of Green component sub-band. The embedding method is based on three levels Discrete Wavelet Transform (DWT low coefficient. A threshold is used to generate frequency of watermarks with the compare o

6、f created frequency of DWT inembedding position. Experimental results showed that the embedded watermark is robust against various signal processing and compression attacks such as Salt & pepper noise addition, Cropping, Scaling, JPEG compression, Mean filtering, Copying and pasting and so on.Keywor

7、ds: 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.5 Figure: 2.2 Communication channel for cryptosystem7 Figure 2.3 Monograms figuring TGE RG.8 Figure 2.4 Ge

8、neric digital watermarking scheme 11Figure 2.5 Generic digital watermarking decoder .11 Figure 2.6 Gen eric digital watermarking scheme 13 Figure 2.7 Basic watermark embedding scheme .14 Figure 2.8 Basic watermarking Decoding system15 Figure 2.9 Classification of watermarking algorithms based on dom

9、ain used for thewatermarking embedding process .16 Figure 2.10 Classification of watermarking based on applications .17 Figure 2.11 Digital watermarking requirements triangle 20Figure 3.1 Watermarks in Mark and Dollar bank notes .24Figure 3.2 Visible watermark.24Figure 3.3 Invisible watermark 25Figu

10、re 3.4 Delivering Digital data to a trusted End system.26 Figure 3.5 Delivering Digital data to the customer26 Figure 3.6 Conflict: Alice and Bob can both detect their respective watermark in image I28 Figure 3.7 Image Lena Copying or distributing in print or electronic forms withoutwritten permissi

11、on31 Figure 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.36 Figure 3.9 The wavelet pyramid of three-level image decomposition. Each level consists of three detail images, which correspond to horizo

12、ntal, vertical, and diagonal details of each resolution level. xy stands for applying filter x in row direction and filter y in column direction, where L means low-pass filtering, H high-pass filtering, and C is the coarse image .38 4Figure 4.1 DWT three level decomposition flow chat of a color imag

13、e.40 Figure 4.2 Watermark Embedding Algorithm flowchart 42 Figure 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 of attacks (a, b, c, d.45 5List of TableTable 2.1 Number

14、of publications on digital watermarking during the past few yearsaccording to Watermarking world .org .15 Table 2.2 Number of publications on digital watermarking during the past few years according to INSPEC, Jan, 1999. .15 Table 4.1 The Detection response between the extracted watermarks and the a

15、ttacked watermarked image under different types of attacks 46IVHunan UniversityStatement of OriginalityI hereby certify that the thesis submitted is based on the research carried out by myself independently under the guidance and supervision of my supervisor. Any ideas orquotations from the work of

16、other individual and collective works are fully acknowledged in accordance with the standard referencing practices of the discipline.Authors Signature: Date: -May , 28, 2007Copyright StatementPermission is herewith granted to Hunan University to circulate and to have copied for non-commercial purpos

17、es, at its discretion, this thesis upon the request of individuals orinstitutions. The author does not reserve other publication rights and the thesis nor may extensive extracts from it be printed or otherwise reproduced without the authors written permission.This thesis belongs to:1. Secure , and t

18、his power of attorney is valid after _.2. Not Secure(Please mark the above corresponding check boxAuthors Signature: Date: May,_,2007Supervisors Signature: Date: May, _,20071Chapter 1 Introduction1.1 PreambleIn recent years, the development of the Internet and multimedia technology, it is easier to

19、produce, 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. The digital watermarking technique can solve the problem. The digital watermark which is represents the ownership of the owner

20、according to the embedding information into the original image. It can be applied to different applications including digital signatures, fingerprinting, broadcast and publication monitoring, authentication, copy control and secret communication 2. Usually, an effective digital watermark scheme prov

21、ides the three major properties 3. (iImperceptibility (ii Robustness and (iii Un ambiguity. The embedded watermarking must be imperceptibility and invisible because of two primary concerns; firstly we should not lower the quality of the original image or it will the break the aesthetic feeling and d

22、iminish the commercial value of the original. Second, if the watermark 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 after some digital image processing such as lossy or lossless image compress

23、ion. In the watermark extraction process, it should be unambiguous to prove the ownership of the owner 3. One of the primary watermarking designing considerations is that the invisibility and robustness often collide 4. In order to improve the robustness of the watermarking scheme, we must embed mor

24、e and more watermark information and therefore cause the quality of the image lower and lower. It seems like that the original image has been interfered with much more noise. On the other hand, in order to keep the quality of the original image, we embed fewer information and high robust ofwatermark

25、ing scheme. 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 waterm

26、ark. There are many 2researches and develops have been done grayscale image but the color image is not sufficient. 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 not suitable for embedding water

27、mark. Some proposed embedding schemes focus onembedding watermarks in the Y component (luminance in YIQ model. Kutter et al 6 embed the watermark by modifying selected set pixels in the blue channel because of its low sensitivity to human perception. The blue channel is the best choose to JPEGcompre

28、ssion among the RGB because of its low sensitivity to human perception. So the hidden watermark is easy to be lost. Red Channel embedding watermark problem is its very large energy loss. During the RGB true color image compressed into JEPG, theembedding watermark in the red channel is easy to lost a

29、nd difficult to extract. Otherwise green channel can endure JEPG compression and the embedded watermark is robust enough. So our select is Green channel to embed watermark information to examine its capability.1.2 MotivationModern age is the age of digital technologies. The digital information excha

30、nge like as Internet and multimedia technology becomes easier to produce, distribute, modify,acquire and copy digital media products such as digital text, image, video and audio. But these results create serious problem because unauthorized copying and modification of the context. Any one can easily

31、 copy the digital products from internet and it becomes very easy to get benefit from it without owner permission. Even they can claim that they are the owners of the copyright.For this reason piracy becomes great threat for innovation and business. In order to solve intellectual property problems o

32、f the digital age, the owner have the protection of the contents of digital products, its carry on evidence of copyright. Digital watermarking techniques are the best solution for the digital distribution.31.3 Research ScopeThe features of the digital world lead to economical chances such as cheap d

33、istribution and also to serious risks in simplifying unauthorized copying and distribution(Rosenblatt, Trippe, & Mooney, 2002. Digital media, like audio, video, images, and other multimedia documents, can be protected against copyright infringements with invisible, integrated patterns. Such methods

34、are based on digital watermarkingtechniques. In the field of image watermarking, many algorithms have developed last few years. Most watermarking algorithms are not resistant to all attacks and even friendly attacks such as file and data modifications can easily destroy the watermark. In this resear

35、ch, A DWT based color image watermarking technique is proposed to solve the problem of invisibility and robust against attracts. We choose Green channel of a color image to embed watermark information based on image Discrete Wavelet Transform. The DWT is a hierarchical sub-band system, where the sub

36、 bands are logarithmically spread in frequency and the green channel can endure JEPG compression and also the embedded watermark is robust enough. The aim of this research is investigate the capability of green channel of RGB color image as a carrier of embedding watermark information and understand

37、ing embedding strength theoretical and practical passingthrough 3 levels DWT into green channel of a color image. Embedding watermark in the low component is robust than high and middle component. That is why we select Green channel low component to embed watermark information.1.4 The Thesis Organiz

38、ationChapter 2 gives an overview of information hiding technique in watermarking, Rationale with steganograpy and cryptography, History of watermark, Watermark System,Watermark Principles, Watermark Classification and Application. Chapter 3 discusses details image water marking, classification and a

39、pplication. Chapter 4 Implementation and Experiments of digital color image watermarking technique, presented “A Robust Wavelet-based Color Image digital Watermarking Embedding and Extraction Algorithm”. Chapter 5 general conclusion and future work.4Chapter 2 Digital Watermarking2.1 IntroductionDigi

40、tal watermarking means embedding information into digital material in such a way that it is imperceptible to a human observer, robustness and un ambiguity but easilydetected by computer algorithm. Another way we can say the watermark is one, which is imperceptibly added to the cover-signal in order

41、to convey the hidden data. A digital watermark is transparent, invisible information pattern that is inserted into a suitable component of the data source by using a specific computer algorithm.7 . Most of the recent use of information hiding is for watermarking and mainly in copyright protection, a

42、uthentication and fingerprinting. Digital watermarking techniques have been developed to protect the copyright of media signals. Different watermarking schemes have been suggested for multimedia content (images, video and audio signal 8 910 which can be detected or extracted by means of computing op

43、erations in order to make assertions about the data. Watermarking has its applications in image/video copyright protection. Copyright protection inserts copyright information into the digital object without the loss of quality. Whenever the copyright of a digital object is in question, this informat

44、ion is extracted to identify the rightful owner. It is also possible to encode the identity of the original buyer along with the identity of the copyright holder, which allows tracing of any unauthorized copies. The most prominent way of embedding information in multimedia data is the use of digital

45、 watermarking. (Watermark2.2 RationaleSteganography and watermarking describe methods to embed information transparently into a carrier signal. Steganography is the art and science of hiding communication: a steganographic system thus embeds hidden content in unremarkable cover media so as 5not to a

46、rouse an eavesdroppers suspicion. Steganographic systems can hide messagesinside of images or other digital objects. As the purpose of steganography is having a covert communication between two parties whose existence is unknown to a possible attacker, a successful attack consists in detecting the e

47、xistence of this communication (e.g., using statistical analysis of images with and without hidden information. To a casual observer inspecting these images, the messages are invisible. In February 2000, USA Today reported that terrorists are using steganography to hide their communication from law enforcement 11 Accoring to them, messages are being hidden in images posted to Internet auction sides like eBay or Amazon. Today, computer and network technologies provide easy-to-use communication channels for steganography 12. However, modern steganography