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Dissertations / Theses on the topic 'Watermarking algorithms'

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Published: 4 June 2021

Last updated: 1 February 2022

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Gordy, James D. "Performance evaluation of digital watermarking algorithms." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0015/MQ49675.pdf.

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Cvejic, N. (Nedeljko). "Algorithms for audio watermarking and steganography." Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514273842.

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Abstract Broadband communication networks and multimedia data available in a digital format opened many challenges and opportunities for innovation. Versatile and simple-to-use software and decreasing prices of digital devices have made it possible for consumers from all around the world to create and exchange multimedia data. Broadband Internet connections and near error-free transmission of data facilitate people to distribute large multimedia files and make identical digital copies of them. A perfect reproduction in digital domain have promoted the protection of intellectual ownership and the prevention of unauthorized tampering of multimedia data to become an important technological and research issue. Digital watermarking has been proposed as a new, alternative method to enforce intellectual property rights and protect digital media from tampering. Digital watermarking is defined as imperceptible, robust and secure communication of data related to the host signal, which includes embedding into and extraction from the host signal. The main challenge in digital audio watermarking and steganography is that if the perceptual transparency parameter is fixed, the design of a watermark system cannot obtain high robustness and a high watermark data rate at the same time. In this thesis, we address three research problems on audio watermarking: First, what is the highest watermark bit rate obtainable, under the perceptual transparency constraint, and how to approach the limit? Second, how can the detection performance of a watermarking system be improved using algorithms based on communications models for that system? Third, how can overall robustness to attacks to a watermark system be increased using attack characterization at the embedding side? An approach that combined theoretical consideration and experimental validation, including digital signal processing, psychoacoustic modeling and communications theory, is used in developing algorithms for audio watermarking and steganography. The main results of this study are the development of novel audio watermarking algorithms, with the state-of-the-art performance and an acceptable increase in computational complexity. The algorithms' performance is validated in the presence of the standard watermarking attacks. The main technical solutions include algorithms for embedding high data rate watermarks into the host audio signal, using channel models derived from communications theory for watermark transmission and the detection and modeling of attacks using attack characterization procedure. The thesis also includes a thorough review of the state-of-the-art literature in the digital audio watermarking.

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Terzija, Nataša. "Robust digital image watermarking algorithms for copyright protection." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982382553.

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Liang, Te-Shen. "Methods for improved robustness of image watermarking algorithms." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/284164.

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With the advent of multimedia technology and the popularity of Internet communications, there has been great interest in using digital watermarks for the purpose of copy protection and content authentication. Digital watermarking technology allows the content owner to embed a secret signature, i.e., watermark, into the host content for many applications. For digital watermarking, the major challenge lies in the confident verification of the embedded watermark, even after the watermarked content undergoes various forms of unintentional or malicious modification. Approaches aiming to guarantee reliable verification of an imperceptible watermark are termed robust watermarking algorithms. In this dissertation, we study digital image watermarking and provide more robust algorithms toward reliable watermark verification, assuming various types of "content-preserving" image processing. Three new algorithms based on attack analysis, spectrum equalization, and a modified embedding rule are proposed. We discuss and analyze the proposed solutions, and compare them thoroughly against conventional algorithms. Since the watermark robustness is to be tested under various forms of image processing, the watermark encoder can utilize the knowledge of some possible attacks for a more secure embedding. Our first solution toward robust image watermarking is to select the set of best watermarking coefficients through attack analysis using the un-watermarked, original image. For transform-domain algorithms, the discrete cosine transform (DCT) or discrete wavelet transform (DWT) are normally used for decomposing the host image before embedding the watermark. Due to the low-pass characteristic of most images, the DCT/DWT coefficients generally vary in amplitude throughout the image spectrum. This low-pass nature is an advantage for many transform coders, but it does not facilitate a reliable watermark extraction for many watermarking algorithms. Our second solution for a more robust watermarking is the use of a simple, invertible permutation operator to equalize the transform coefficients before watermarking. Many transform-domain schemes utilize a directly-proportional rule for embedding the watermark. This approach results in diminishing performance as the watermark capacity increases. Our third solution provides a new embedding scheme that is inversely dependent on the magnitude of the selected transform coefficients. This scheme enhances performance, enabling a large-capacity watermark.

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Chen, Bingwei. "Adaptive watermarking algorithms for MP3 compressed audio signals." Thesis, University of Ottawa (Canada), 2008. http://hdl.handle.net/10393/27963.

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MPEG-1 Layer 3, known as MP3, has generated a significant popularity for distributing digital music over the Internet. MP3 compresses digital music with high ratio while keeping high sound quality. However, copyright issue is raised because of illegal copy, redistribution and various malicious attacks. Digital watermarking is a technology that allows users to embed some imperceptible data into digital contents such as image, movie and audio data. Once a watermark is embedded into the original MP3 signal, it can be used to identify the copyright holder in order to prevent illegal copy and to verify the modification from the original content. This thesis presents two novel adaptive watermarking algorithms for MP3 compressed audio signals for copyright protection. Based on Human Auditory System, the proposed algorithms calculate the energy of the original audio signal and apply Gaussian analysis on MP3 frames to adaptively adjust the watermarking coefficients. Watermark is embedded adaptively and transparently during the MP3 compression. The first watermarking algorithm detects watermark based on Gaussian distribution analysis. To enhance the security of the watermark, the second watermarking algorithm embeds random watermark pattern and uses correlation coefficient to detect watermark. Both algorithms support blind watermark detection and perform well. The first algorithm is more robust while the second algorithm is more secure. LAME 3.96.2 open source was used as standard ISO MP3 encoder and decoder reference in this study. The experimental results show that the proposed watermarking algorithms can work on a variety of audio signals and survive most common signal manipulation and malicious attacks. As expected, the watermarking algorithms provide superior performance on MP3 compression.

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Kundar, Deepa. "Multiresolution digital watermarking, algorithms and implications for multimedia signals." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0021/NQ45689.pdf.

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Serdean, Cristian Vasile. "Spread spectrum-based video watermarking algorithms for copyright protection." Thesis, University of Plymouth, 2002. http://hdl.handle.net/10026.1/2263.

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Digital technologies know an unprecedented expansion in the last years. The consumer can now benefit from hardware and software which was considered state-of-the-art several years ago. The advantages offered by the digital technologies are major but the same digital technology opens the door for unlimited piracy. Copying an analogue VCR tape was certainly possible and relatively easy, in spite of various forms of protection, but due to the analogue environment, the subsequent copies had an inherent loss in quality. This was a natural way of limiting the multiple copying of a video material. With digital technology, this barrier disappears, being possible to make as many copies as desired, without any loss in quality whatsoever. Digital watermarking is one of the best available tools for fighting this threat. The aim of the present work was to develop a digital watermarking system compliant with the recommendations drawn by the EBU, for video broadcast monitoring. Since the watermark can be inserted in either spatial domain or transform domain, this aspect was investigated and led to the conclusion that wavelet transform is one of the best solutions available. Since watermarking is not an easy task, especially considering the robustness under various attacks several techniques were employed in order to increase the capacity/robustness of the system: spread-spectrum and modulation techniques to cast the watermark, powerful error correction to protect the mark, human visual models to insert a robust mark and to ensure its invisibility. The combination of these methods led to a major improvement, but yet the system wasn't robust to several important geometrical attacks. In order to achieve this last milestone, the system uses two distinct watermarks: a spatial domain reference watermark and the main watermark embedded in the wavelet domain. By using this reference watermark and techniques specific to image registration, the system is able to determine the parameters of the attack and revert it. Once the attack was reverted, the main watermark is recovered. The final result is a high capacity, blind DWr-based video watermarking system, robust to a wide range of attacks.

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Parker, Kristen Michelle. "Watermarking with wavelet transforms." Master's thesis, Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-11062007-153859.

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Sun, Wei. "Joint Compression and Digital Watermarking: Information-Theoretic Study and Algorithms Development." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2890.

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In digital watermarking, a watermark is embedded into a covertext in such a way that the resulting watermarked signal is robust to certain distortion caused by either standard data processing in a friendly environment or malicious attacks in an unfriendly environment. The watermarked signal can then be used for different purposes ranging from copyright protection, data authentication,fingerprinting, to information hiding. In this thesis, digital watermarking will be investigated from both an information theoretic viewpoint and a numerical computation viewpoint. From the information theoretic viewpoint, we first study a new digital watermarking scenario, in which watermarks and covertexts are generated from a joint memoryless watermark and covertext source. The configuration of this scenario is different from that treated in existing digital watermarking works, where watermarks are assumed independent of covertexts. In the case of public watermarking where the covertext is not accessible to the watermark decoder, a necessary and sufficient condition is determined under which the watermark can be fully recovered with high probability at the end of watermark decoding after the watermarked signal is disturbed by a fixed memoryless attack channel. Moreover, by using similar techniques, a combined source coding and Gel'fand-Pinsker channel coding theorem is established, and an open problem proposed recently by Cox et al is solved. Interestingly, from the sufficient and necessary condition we can show that, in light of the correlation between the watermark and covertext, watermarks still can be fully recovered with high probability even if the entropy of the watermark source is strictly above the standard public watermarking capacity. We then extend the above watermarking scenario to a case of joint compression and watermarking, where the watermark and covertext are correlated, and the watermarked signal has to be further compressed. Given an additional constraint of the compression rate of the watermarked signals, a necessary and sufficient condition is determined again under which the watermark can be fully recovered with high probability at the end of public watermark decoding after the watermarked signal is disturbed by a fixed memoryless attack channel. The above two joint compression and watermarking models are further investigated under a less stringent environment where the reproduced watermark at the end of decoding is allowed to be within certain distortion of the original watermark. Sufficient conditions are determined in both cases, under which the original watermark can be reproduced with distortion less than a given distortion level after the watermarked signal is disturbed by a fixed memoryless attack channel and the covertext is not available to the watermark decoder. Watermarking capacities and joint compression and watermarking rate regions are often characterized and/or presented as optimization problems in information theoretic research. However, it does not mean that they can be calculated easily. In this thesis we first derive closed forms of watermarking capacities of private Laplacian watermarking systems with the magnitude-error distortion measure under a fixed additive Laplacian attack and a fixed arbitrary additive attack, respectively. Then, based on the idea of the Blahut-Arimoto algorithm for computing channel capacities and rate distortion functions, two iterative algorithms are proposed for calculating private watermarking capacities and compression and watermarking rate regions of joint compression and private watermarking systems with finite alphabets. Finally, iterative algorithms are developed for calculating public watermarking capacities and compression and watermarking rate regions of joint compression and public watermarking systems with finite alphabets based on the Blahut-Arimoto algorithm and the Shannon's strategy.

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Jassim, Taha D. "Combined robust and fragile watermarking algorithms for still images. Design and evaluation of combined blind discrete wavelet transform-based robust watermarking algorithms for copyright protection using mobile phone numbers and fragile watermarking algorithms for content authentication of digital still images using hash functions." Thesis, University of Bradford, 2014. http://hdl.handle.net/10454/6460.

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This thesis deals with copyright protection and content authentication for still images. New blind transform domain block based algorithms using one-level and two-level Discrete Wavelet Transform (DWT) were developed for copyright protection. The mobile number with international code is used as the watermarking data. The robust algorithms used the Low-Low frequency coefficients of the DWT to embed the watermarking information. The watermarking information is embedded in the green channel of the RGB colour image and Y channel of the YCbCr images. The watermarking information is scrambled by using a secret key to increase the security of the algorithms. Due to the small size of the watermarking information comparing to the host image size, the embedding process is repeated several times which resulted in increasing the robustness of the algorithms. Shuffling process is implemented during the multi embedding process in order to avoid spatial correlation between the host image and the watermarking information. The effects of using one-level and two-level of DWT on the robustness and image quality have been studied. The Peak Signal to Noise Ratio (PSNR), the Structural Similarity Index Measure (SSIM) and Normalized Correlation Coefficient (NCC) are used to evaluate the fidelity of the images. Several grey and still colour images are used to test the new robust algorithms. The new algorithms offered better results in the robustness against different attacks such as JPEG compression, scaling, salt and pepper noise, Gaussian noise, filters and other image processing compared to DCT based algorithms. The authenticity of the images were assessed by using a fragile watermarking algorithm by using hash function (MD5) as watermarking information embedded in the spatial domain. The new algorithm showed high sensitivity against any tampering on the watermarked images. The combined fragile and robust watermarking caused minimal distortion to the images. The combined scheme achieved both the copyright protection and content authentication.

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Jassim, Taha Dawood. "Combined robust and fragile watermarking algorithms for still images : design and evaluation of combined blind discrete wavelet transform-based robust watermarking algorithms for copyright protection using mobile phone numbers and fragile watermarking algorithms for content authentication of digital still images using hash functions." Thesis, University of Bradford, 2014. http://hdl.handle.net/10454/6460.

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Nasir, Ibrahim A. "Digital Watermarking of Images towards Content Protection." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4432.

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With the rapid growth of the internet and digital media techniques over the last decade, multimedia data such as images, video and audio can easily be copied, altered and distributed over the internet without any loss in quality. Therefore, protection of ownership of multimedia data has become a very significant and challenging issue. Three novel image watermarking algorithms have been designed and implemented for copyright protection. The first proposed algorithm is based on embedding multiple watermarks in the blue channel of colour images to achieve more robustness against attacks. The second proposed algorithm aims to achieve better trade-offs between imperceptibility and robustness requirements of a digital watermarking system. It embeds a watermark in adaptive manner via classification of DCT blocks with three levels: smooth, edges and texture, implemented in the DCT domain by analyzing the values of AC coefficients. The third algorithm aims to achieve robustness against geometric attacks, which can desynchronize the location of the watermark and hence cause incorrect watermark detection. It uses geometrically invariant feature points and image normalization to overcome the problem of synchronization errors caused by geometric attacks. Experimental results show that the proposed algorithms are robust and outperform related techniques found in literature.

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Nasir, Ibrahim Alsonosi. "Digital watermarking of images towards content protection." Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4432.

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Al-Gindy, Ahmed M. N. "Design and analysis of Discrete Cosine Transform-based watermarking algorithms for digital images. Development and evaluation of blind Discrete Cosine Transform-based watermarking algorithms for copyright protection of digital images using handwritten signatures and mobile phone numbers." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5450.

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This thesis deals with the development and evaluation of blind discrete cosine transform-based watermarking algorithms for copyright protection of digital still images using handwritten signatures and mobile phone numbers. The new algorithms take into account the perceptual capacity of each low frequency coefficients inside the Discrete Cosine Transform (DCT) blocks before embedding the watermark information. They are suitable for grey-scale and colour images. Handwritten signatures are used instead of pseudo random numbers. The watermark is inserted in the green channel of the RGB colour images and the luminance channel of the YCrCb images. Mobile phone numbers are used as watermarks for images captured by mobile phone cameras. The information is embedded multiple-times and a shuffling scheme is applied to ensure that no spatial correlation exists between the original host image and the multiple watermark copies. Multiple embedding will increase the robustness of the watermark against attacks since each watermark will be individually reconstructed and verified before applying an averaging process. The averaging process has managed to reduce the amount of errors of the extracted information. The developed watermarking methods are shown to be robust against JPEG compression, removal attack, additive noise, cropping, scaling, small degrees of rotation, affine, contrast enhancements, low-pass, median filtering and Stirmark attacks. The algorithms have been examined using a library of approximately 40 colour images of size 512 512 with 24 bits per pixel and their grey-scale versions. Several evaluation techniques were used in the experiment with different watermarking strengths and different signature sizes. These include the peak signal to noise ratio, normalized correlation and structural similarity index measurements. The performance of the proposed algorithms has been compared to other algorithms and better invisibility qualities with stronger robustness have been achieved.

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Fylakis, A. (Angelos). "Data hiding algorithms for healthcare applications." Doctoral thesis, Oulun yliopisto, 2019. http://urn.fi/urn:isbn:9789526224008.

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Abstract Developments in information technology have had a big impact in healthcare, producing vast amounts of data and increasing demands associated with their secure transfer, storage and analysis. To serve them, biomedical data need to carry patient information and records or even extra biomedical images or signals required for multimodal applications. The proposed solution is to host this information in data using data hiding algorithms through the introduction of imperceptible modiﬁcations achieving two main purposes: increasing data management efﬁciency and enhancing the security aspects of conﬁdentiality, reliability and availability. Data hiding achieve this by embedding the payload in objects, including components such as authentication tags, without requirements in extra space or modiﬁcations in repositories. The proposed methods satisfy two research problems. The ﬁrst is the hospital-centric problem of providing efﬁcient and secure management of data in hospital networks. This includes combinations of multimodal data in single objects. The host data were biomedical images and sequences intended for diagnoses meaning that even non-visible modiﬁcations can cause errors. Thus, a determining restriction was reversibility. Reversible data hiding methods remove the introduced modiﬁcations upon extraction of the payload. Embedding capacity was another priority that determined the proposed algorithms. To meet those demands, the algorithms were based on the Least Signiﬁcant Bit Substitution and Histogram Shifting approaches. The second was the patient-centric problem, including user authentication and issues of secure and efﬁcient data transfer in eHealth systems. Two novel solutions were proposed. The ﬁrst method uses data hiding to increase the robustness of face biometrics in photos, where due to the high robustness requirements, a periodic pattern embedding approach was used. The second method protects sensitive user data collected by smartphones. In this case, to meet the low computational cost requirements, the method was based on Least Signiﬁcant Bit Substitution. Concluding, the proposed algorithms introduced novel data hiding applications and demonstrated competitive embedding properties in existing applications Tiivistelmä Modernit terveydenhuoltojärjestelmät tuottavat suuria määriä tietoa, mikä korostaa tiedon turvalliseen siirtämiseen, tallentamiseen ja analysointiin liittyviä vaatimuksia. Täyttääkseen nämä vaatimukset, biolääketieteellisen tiedon täytyy sisältää potilastietoja ja -kertomusta, jopa biolääketieteellisiä lisäkuvia ja -signaaleja, joita tarvitaan multimodaalisissa sovelluksissa. Esitetty ratkaisu on upottaa tämä informaatio tietoon käyttäen tiedonpiilotusmenetelmiä, joissa näkymättömiä muutoksia tehden saavutetaan kaksi päämäärää: tiedonhallinnan tehokkuuden nostaminen ja luottamuksellisuuteen, luotettavuuteen ja saatavuuteen liittyvien turvallisuusnäkökulmien parantaminen. Tiedonpiilotus saavuttaa tämän upottamalla hyötykuorman, sisältäen komponentteja, kuten todentamismerkinnät, ilman lisätilavaatimuksia tai muutoksia tietokantoihin. Esitetyt menetelmät ratkaisevat kaksi tutkimusongelmaa. Ensimmäinen on sairaalakeskeinen ongelma tehokkaan ja turvallisen tiedonhallinnan tarjoamiseen sairaaloiden verkoissa. Tämä sisältää multimodaalisen tiedon yhdistämisen yhdeksi kokonaisuudeksi. Tiedon kantajana olivat biolääketieteelliset kuvat ja sekvenssit, jotka on tarkoitettu diagnosointiin, missä jopa näkymättömät muutokset voivat aiheuttaa virheitä. Siispä määrittävin rajoite oli palautettavuus. Palauttavat tiedonpiilotus-menetelmät poistavat lisätyt muutokset, kun hyötykuorma irrotetaan. Upotuskapasiteetti oli toinen tavoite, joka määritteli esitettyjä algoritmeja. Saavuttaakseen nämä vaatimukset, algoritmit perustuivat vähiten merkitsevän bitin korvaamiseen ja histogrammin siirtämiseen. Toisena oli potilaskeskeinen ongelma, joka sisältää käyttäjän henkilöllisyyden todentamisen sekä turvalliseen ja tehokkaaseen tiedonsiirtoon liittyvät haasteet eHealth-järjestelmissä. Työssä ehdotettiin kahta uutta ratkaisua. Ensimmäinen niistä käyttää tiedonpiilotusta parantamaan kasvojen biometriikan kestävyyttä valokuvissa. Korkeasta kestävyysvaatimuksesta johtuen käytettiin periodisen kuvion upottamismenetelmää. Toinen menetelmä suojelee älypuhelimien keräämää arkaluontoista käyttäjätietoa. Tässä tapauksessa, jotta matala laskennallinen kustannus saavutetaan, menetelmä perustui vähiten merkitsevän bitin korvaamiseen. Yhteenvetona ehdotetut algoritmit esittelivät uusia tiedonpiilotussovelluksia ja osoittivat kilpailukykyisiä upotusominaisuuksia olemassa olevissa sovelluksissa

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Dang, Hieu. "Adaptive multiobjective memetic optimization: algorithms and applications." Journal of Cognitive Informatics and Natural Intelligence, 2012. http://hdl.handle.net/1993/30856.

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The thesis presents research on multiobjective optimization based on memetic computing and its applications in engineering. We have introduced a framework for adaptive multiobjective memetic optimization algorithms (AMMOA) with an information theoretic criterion for guiding the selection, clustering, and local refinements. A robust stopping criterion for AMMOA has also been introduced to solve non-linear and large-scale optimization problems. The framework has been implemented for different benchmark test problems with remarkable results. This thesis also presents two applications of these algorithms. First, an optimal image data hiding technique has been formulated as a multiobjective optimization problem with conflicting objectives. In particular, trade-off factors in designing an optimal image data hiding are investigated to maximize the quality of watermarked images and the robustness of watermark. With the fixed size of a logo watermark, there is a conflict between these two objectives, thus a multiobjective optimization problem is introduced. We propose to use a hybrid between general regression neural networks (GRNN) and the adaptive multiobjective memetic optimization algorithm (AMMOA) to solve this challenging problem. This novel image data hiding approach has been implemented for many different test natural images with remarkable robustness and transparency of the embedded logo watermark. We also introduce a perceptual measure based on the relative Rényi information spectrum to evaluate the quality of watermarked images. The second application is the problem of joint spectrum sensing and power control optimization for a multichannel, multiple-user cognitive radio network. We investigated trade-off factors in designing efficient spectrum sensing techniques to maximize the throughput and minimize the interference. To maximize the throughput of secondary users and minimize the interference to primary users, we propose a joint determination of the sensing and transmission parameters of the secondary users, such as sensing times, decision threshold vectors, and power allocation vectors. There is a conflict between these two objectives, thus a multiobjective optimization problem is used again in the form of AMMOA. This algorithm learns to find optimal spectrum sensing times, decision threshold vectors, and power allocation vectors to maximize the averaged opportunistic throughput and minimize the averaged interference to the cognitive radio network. February 2016

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Al-Nu'aimi, Abdallah S. N. A. "Design, Implementation and Performance Evaluation of Robust and Secure Watermarking Techniques for Digital Coloured Images. Designing new adaptive and robust imaging techniques for embedding and extracting 2D watermarks in the spatial and transform domain using imaging and signal processing techniques." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4255.

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The tremendous spreading of multimedia via Internet motivates the watermarking as a new promising technology for copyright protection. This work is concerned with the design and development of novel algorithms in the spatial and transform domains for robust and secure watermarking of coloured images. These algorithms are adaptive, content-dependent and compatible with the Human Visual System (HVS). The host channels have the ability to host a large information payload. Furthermore, it has enough capacity to accept multiple watermarks. Abstract This work achieves several contributions in the area of coloured images watermarking. The most challenging problem is to get a robust algorithm that can overcome geometric attacks, which is solved in this work. Also, the search for a very secure algorithm has been achieved via using double secret keys. In addition, the problem of multiple claims of ownership is solved here using an unusual approach. Furthermore, this work differentiates between terms, which are usually confusing the researchers and lead to misunderstanding in most of the previous algorithms. One of the drawbacks in most of the previous algorithms is that the watermark consists of a small numbers of bits without strict meaning. This work overcomes this weakness III in using meaningful images and text with large amounts of data. Contrary to what is found in literature, this work shows that the green-channel is better than the blue-channel to host the watermarks. A more general and comprehensive test bed besides a broad band of performance evaluation is used to fairly judge the algorithms.

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Al-Nu'aimi, Abdallah Saleem Na. "Design, implementation and performance evaluation of robust and secure watermarking techniques for digital coloured images : designing new adaptive and robust imaging techniques for embedding and extracting 2D watermarks in the spatial and transform domain using imaging and signal processing techniques." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4255.

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Samuel, Sindhu. "Digital rights management (DRM) : watermark encoding scheme for JPEG images." Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-09122008-182920/.

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Cai, Wei Kougianos Elias Mohanty Saraju. "FPGA prototyping of a watermarking algorithm for MPEG-4." [Denton, Tex.] : University of North Texas, 2007. http://digital.library.unt.edu/permalink/meta-dc-3695.

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Cai, Wei. "FPGA Prototyping of a Watermarking Algorithm for MPEG-4." Thesis, University of North Texas, 2007. https://digital.library.unt.edu/ark:/67531/metadc3695/.

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In the immediate future, multimedia product distribution through the Internet will become main stream. However, it can also have the side effect of unauthorized duplication and distribution of multimedia products. That effect could be a critical challenge to the legal ownership of copyright and intellectual property. Many schemes have been proposed to address these issues; one is digital watermarking which is appropriate for image and video copyright protection. Videos distributed via the Internet must be processed by compression for low bit rate, due to bandwidth limitations. The most widely adapted video compression standard is MPEG-4. Discrete cosine transform (DCT) domain watermarking is a secure algorithm which could survive video compression procedures and, most importantly, attacks attempting to remove the watermark, with a visibly degraded video quality result after the watermark attacks. For a commercial broadcasting video system, real-time response is always required. For this reason, an FPGA hardware implementation is studied in this work. This thesis deals with video compression, watermarking algorithms and their hardware implementation with FPGAs. A prototyping VLSI architecture will implement video compression and watermarking algorithms with the FPGA. The prototype is evaluated with video and watermarking quality metrics. Finally, it is seen that the video qualities of the watermarking at the uncompressed vs. the compressed domain are only 1dB of PSNR lower. However, the cost of compressed domain watermarking is the complexity of drift compensation for canceling the drifting effect.

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Ghosh, Debeshi D. "Audio Watermarking Using DWT Algorithm and Symmetric Key Cryptography." Thesis, California State University, Long Beach, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10263604.

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Watermarking is the process of embedding information into a carrier signal such as audio, video, and images. It is widely used to protect proprietary information in the signal to prevent information theft or duplicity. In this project, an audio watermarking system with dual layer security has been implemented. The entire system is divided into two sections that are independent, but have been combined, to make a unique system that provides increased levels of robustness. The first part of the project involves encrypting an embedded image (watermark) using the XOR method of symmetric key cryptography. Encryption is then followed by watermarking. The digital wavelet transform (DWT) algorithm was used to embed the encrypted image into an audio signal. This ensures that even if this image is removed during an attack to the carrier signal, it cannot be interpreted or used. Though encryption combined with watermarking is unconventional, it proves to be an effective technique when implemented correctly.

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Bergkvist, David. "Implementation of a Watermarking Algorithm for H.264 Video Sequences." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2352.

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In today's video delivery and broadcast networks, issues of copyright protection have become more urgent than in analog times, since the copying of digital video does not result in the decrease in quality that occurs when analog video is copied. One method of copyright protection is to embed a digital code, a"watermark", into the video sequence. The watermark can then unambiguously identify the copyright holder of the video sequence. Watermarks can also be used to identify the purchaser of a video sequence, which is called "fingerprinting". The objective of this master thesis was to implement a program that would insert watermarks into video sequences and also detect if a given video sequence contains a givenwatermark. The video standard I chose to use was the H.264 standard (also known as MPEG4 AVC) as it offers a significant efficiency improvement over the previous video compression standards. A couple of tests that can be considered representative for most image manipulations and attacks were performed. The program passed all tests, suggesting that the watermarking mechanism of this thesis can be expected to be rather robust, at least for the video sequence used. By looking at the watermarked video sequences and comparing them to the originals, or measuring the signal to noise ratio, one can also see that the watermarks are unobtrusive. The execution times were also measured. Compared to coding and decoding a H.264 video stream, the time it takes to insert and extract watermarks was much less. Calculating a threshold takes roughly double the time as decoding the sequence, though.

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Retsas, Ioannis. "A DCT-based image watermarking algorithm robust to cropping and compression." Thesis, Monterey California. Naval Postgraduate School, 2002. http://hdl.handle.net/10945/6032.

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Approved for public release; distribution is unlimited. Digital watermarking is a highly evolving field, which involves the embedding of a certain kind of information under a digital object (image, video, audio) for the purpose of copyright protection. Both the image and the watermark are most frequently translated into a transform domain where the embedding takes place. The selection of both the transform domain and the particular algorithm that is used for the embedding of the watermark, depend heavily on the application. One of the most widely used transform domains for watermarking of still digital images is the Discrete Cosine Transform domain. The reason is that the Discrete Cosine Transform is a part of the JPEG standard, which in turn is widely used for storage of digital images. In our research we propose a unique methodfor DCT-based image watermarking. In an effort to achieve robustness to cropping and JPEG compression wehave developed an algorithm for rating the 8.8 blocks of the image DCT coefficients taking into account theirembedding capacity and their spatial location within the image. Our experiments show that the proposed schemeoffers adequate transparency, and works exceptionally well against cropping while at the same time maintainssufficient robustness to JPEG compression.

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Zarate, Orozco Ismael. "Software and Hardware-In-The-Loop Modeling of an Audio Watermarking Algorithm." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc33221/.

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Due to the accelerated growth in digital music distribution, it becomes easy to modify, intercept, and distribute material illegally. To overcome the urgent need for copyright protection against piracy, several audio watermarking schemes have been proposed and implemented. These digital audio watermarking schemes have the purpose of embedding inaudible information within the host file to cover copyright and authentication issues. This thesis proposes an audio watermarking model using MATLAB® and Simulink® software for 1K and 2K fast Fourier transform (FFT) lengths. The watermark insertion process is performed in the frequency domain to guarantee the imperceptibility of the watermark to the human auditory system. Additionally, the proposed audio watermarking model was implemented in a Cyclone® II FPGA device from Altera® using the Altera® DSP Builder tool and MATLAB/Simulink® software. To evaluate the performance of the proposed audio watermarking scheme, effectiveness and fidelity performance tests were conducted for the proposed software and hardware-in-the-loop based audio watermarking model.

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Piergigli, Daniele. "Social network e watermarking: alcuni risultati preliminari." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11943/.

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La diffusione dei social network ha permesso ad un elevato numero di persone di condividere i propri contenuti multimediali (testo, foto, video) con una larga platea di contatti. Potenzialmente questi contenuti possono essere condivisi anche con persone non direttamente collegate al proprietario. Uno dei comportamenti più diffuso degli utenti dei social network è la condivisione di foto. In questo contesto diventa importante riconoscere e preservare la proprietà di un'immagine. Lo studio effettuato in questo documento quindi, si prefigge lo scopo di controllare se i social network inseriscano un qualche watermark all'interno dell'immagine caricata. L'elaborato inoltre cerca di capire, analizzando e testando vari algoritmi di watermarking su immagini condivise, come le firme digitali vengano inserite all'interno di una foto e come queste rispondano alle alterazioni da parte dei social network.

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Baudry, Séverine. "Stratégies de codage de canal pour le tatouage de video." Paris, ENST, 2002. http://www.theses.fr/2002ENST0006.

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Chih-chen, Chiang, and 江至晨. "Optimnu JPEG Watermarking Based on Genetic Algorithms." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/62374334771209270590.

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碩士 長榮大學 經營管理研究所 93 With the rapid growth of the Internet, Multimedia, and E-Commerce, it becomes more convenient and fast for the users to interchange the information. However, the image files are extremely huge, it is necessary to use the compression technology to reduce the file space. Digital watermarking is one of commonly used techniques to hide information in images to protect copyright. To increase the application of watermarking area, the two techniques, digital watermarking and high image compression standard of JPEG, will be integrated in the thesis. In the processing of embedding watermark, the quantization field will be obtained from Q. According to the quantization field, the coefficients of DCT will be modified in the processing of embedding the watermark. In order to embed the watermark, middle frequency and the position information of watermark are needed, and the technique of GA is used to obtain the best position for the sake of embedding watermark. By adoptting the GA algorithm, PSNR and NC value will be promoted.

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Hsu, S. W., and 徐紹文. "Adaptive Algorithms for Bar Code-based Watermarking." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/49428772025800965248.

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碩士 國立臺灣大學 電機工程學研究所 89 Base on Internet and computer generalization, it is more important for digital information usage and management, especially for protection of copyright. Watermarking is the one of practical solutions. It not only hides data imperceptibly, but also supports security. Both legal user and owner can acquire well indemnification. In the thesis, we offer bar code-based algorithms and gray-scale coding to approach still-image watermark. It is easy and flexible to embed/extract watermark without any adjuncts, and resists different attack with specific functions. With bar code system and open algorithm, it will be convenient for e-commerce and image application

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Chen, Chih-Cheng, and 陳志丞. "Digital Watermarking Algorithms for Spatial Raster Data." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/49901391570096523649.

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博士 國立臺灣大學 土木工程學研究所 104 This study mainly focused on raster spatial data for digital watermarking analysis and discussion, the explored objects included photogrammetric images, remote sensing images and digital terrain model (DTM). The watermarking algorithm of images are mainly is developed based on image''s feature points for digital watermarking algorithm, and influences and robustness of images after watermark embedding were tested during the study. When conducting copyright protection using watermarking algorithm in the future, relevant results can be used as the reference when evaluating derivational problems from re-processing and geometric transformation of images with watermarks embedded. Moreover, the watermarking algorithm proposed in this study had little influence on the original quality of images after embedding, thus could avoid subsequent application outcomes of images. It was proved by the experimental results that in addition to a certain degree of robustness, the digital watermarking algorithm proposed in this study can also resist attacks from different types of image processing and geometric transformation, and at the same time maintain the quality of images. The second watermarking algorithm for image proposed in this study also based on feature points and adjusted the embedding strength of watermarks according to feature region''s texture sensitivity value, resulting in less anamorphose of images after watermark embedding and higher robustness when images were under geometric attacks such as rotation and resizing. Watermarking algorithm was tested for robustness using geometric corrections such as rotation scale translation (RST) and polynomial transformation targeting remote sensing images, the NC value of watermarks captured from geometrically corrected images through RST is very high. However, the extracted watermark after polynomial transformation is unidentifiable and has a small NC value.The third part of this study is DTM, which is an important national fundamental data. As confirmed through experiments, an aspect-based algorithm was proposed in this study so that the bits of watermark information could be evenly and repeatedly embedded into DTM data, through which not only the number of redundant embedding times could be increased and watermark embedding capacity could be improved, the problem of relatively low data redundancy can also be overcome, thus the data contents would have good robustness even if they were altered because of being attacked.

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Pai, Yu-Ting, and 白御廷. "The Research of Energy-Efficient Watermarking Algorithms." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/80451617224853737700.

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博士 國立臺灣科技大學 電子工程系 97 Digital watermarking is a potential method for copyright protection. In order to achieve robustness, transparency, blindness, and etc., much literature has discussed how to develop a high quality watermarking. Although these previous methods offer the satisfactory results for resisting many attacks, the complicated frameworks cost a lot of area and energy consumption for hardware implementation. Since the chip area and battery life of embedded systems are always restricted, these high complexity watermarking methods are not popular used nowadays. In this dissertation, we are concerned with energy-efficient and robust watermarking technologies. We analyze the computational complexity for three type watermarking algorithms. First, we propose an improvement of basic watermarking algorithm. The frequency coefficients are exploited directly as the criterion for the permutation mapping. The energy and time consumption can be reduced without calculating variance parameter in spatial domain. Second, in order to further reduce power and achieve the requirement of blind extraction, we continue our study based on DS-CDMA based wateramrking algorithm. According to the properties of DCT and DS-CDMA, the inverse discrete cosine transform is qualified to substitute for both forward and inverse transform in proposed method. Thus, we can save quantities of energy and time consumption. Third, the study is focus on overcoming geometric attacks for video. The proposed algorithm provide the robustness via hide watermark in DCT domain, and supply the capability of resisting geometric attacks by embedded a group of template to DFT domain. For power saving, the watermark massage is embedded in DCT domain which is decoded from video directly. In additional, we propose partial DFT and downsampling methods to reduce the huge computational complexity. To validate the results, we employ Wattch toolset developed at Princeton University to evaluate power dissipation and execution time. Moreover, the quality measuring results show that the proposed watermarking algorithms is robust enough against several signal distortions.

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Wang, Chih-peng, and 王智鵬. "Robust Watermarking Algorithms Based on Salient Image Features." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/98298854500271738318.

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碩士 朝陽科技大學 資訊管理系碩士班 96 Due to the rapid development of the Internet and multimedia, a lot of data are in digital formats and transmitted through the networks. Users are able to easily copy and modify digital data almost without any limitations. However, such convenience also results in many security problems. Taking digital images as an example, the problems of copyright protection, authentication of image integrity, transmission security, etc., require technical solutions. And digital watermarking has emerged as one of the promising solutions. The purpose of embedding watermarks in an image is to protect hackers from unauthorized use of the copyright as well as maliciously altering the content. However, attacks such as geometric, signal, and brute-force attacks make watermarks difficult to survive. Among which, geometric attacks such as rotation, scaling, translations, etc. presents the most challenges. This research aims at developing watermarking techniques that are resistant to geometric attacks. Novel feature-based robust watermarking algorithms are developed in this research which are resistant to geometric transformations. First, in addition to the invariance of rotation and translation of Harris corner detector, Harris Laplace detector is used to extract features (corners) to further achieve scaling invariance. Second, a corner enhancement technique is developed to increase the repeatability of corner detection. Third, during the process of extracting the region for watermarking, an annular region is Cartesian-to-polar transformed into a rectangular region. Forth, the image moment is calculated to achieve rotation invariance of Cartesian-to-polar transformation, followed by embedding the watermark based on both DCT and DFT transforms. The experimental results demonstrate that the algorithms developed in this research can survive various geometric transformations as well as common signal processing operations.

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"Digital watermarking algorithms robust against loss of synchronization." Université catholique de Louvain, 2004. http://edoc.bib.ucl.ac.be:81/ETD-db/collection/available/BelnUcetd-04012004-161618/.

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許世龍. "A Study of Effective Watermarking Algorithms for Polygonal Models." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/89902858505727644511.

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碩士 國立中興大學 資訊科學研究所 91 In digital age, protecting intellectual property of original creators of digital media by digital watermarking is an important research issue. Ohbuchi[Ohbu2001] addressed this topic by presenting a watermarking algorithm that employed spectral analysis for polygonal models. However, his approach couldn’t come to zero bit error rates when the stego model is attacked, so its robustness still required improvement. In this thesis, we present a number of techniques to improve the drawbacks of Ohbuchi’s watermarking algorithm for poly gonal models. First, the techniques utilize hamming code encoding method to improve the robustness of Ohbuch’s watermarking algorithm. We use hamming code to encode our watermark in advance, and then embed it into the cover model. When extracting watermark from the stego model, the features of h amming code can detect and correct errors to decrease bit error rates of extracted watermark efficiently and increase robustness of watermarking algorithm. Secondly, the techniques also utilize threshold changing method and polling method in order to improve the robustness of watermarking algorithm. Thre shold changing method fixes the first and second bit of watermark as ‘01’ or ‘10’. When extracting watermark, we use the spectral coefficients related to the first two bits to prod uct a new threshold. Then, we replace the threshold which is always zero in Ohbuchi’s method with the new threshold to judge the correctness of extracted data. Polling method uses majority verdict to decide the value of extracted data. After spread spectrum, each bit of the data will be duplicated to n-bits data. We embed the n-bits data into polygonal models to decrease the effect of being attacked. When the model is attacked, the extracted data will be the same or on the contrary comparing to the embedded data. The polling method is exactly the technique that decides the extracted data as zero or one by which the number in of n-bits extracted data is the majority. We implemented the proposed techniques and collected experimental results for comparison and analysis. The results show that hamming code encoding method can decrease bit error rate of extracted watermark efficiently, doesn’t add burden in execution time and can come to zero bit error rates in some testing models. However, the bit error rate of polling method and threshold changing method comparing to Ohbuchi’s method vary with the different models or parameters. There is no discrimination between good and bad. In age of internet, a third party may eavesdrop when we deliver messages to somebody. If we can hide information into a meaningful but unimportant data and make others unable to find the information from the data directly, it can protect the security of information. Information hiding is exactly a technique that embeds information to digital media, and people can’t become aware of the information. In aspect of information hiding, we propose a novel data-embedding algorithm that can embed digital images into polygonal models. We sum all pixel-values of each row in advance, record the percentage of each pixel in a row and then embed each sum of each row into the cover model. After extracting the sum of each row from the stego model, we use the record of percentage to recover original image. The experimental results show that the RMS error values and the norm of GL difference between the cover model and stego model are far less than one. It means there is almost no divergence between the appearances of two models, and it has come to the purpose of information hiding. When stego model not being attacked or being attacked by similarity transformation, the RMS error values of original image and extracted image are from 3 to 5 and the PSNR values are from 34 to 38. It also means we cannot find divergence between them. We also find that the algorithm has worse resistance to the attack of mesh smoothing or random noise. There is large divergence between extracting image and original image. Therefore, how to increase the robustness is still a pending problem. We have presented an efficient watermarking algorithm for polygonal models. Hamming code encoding method can decrease bit error rate, doesn’t add burden in execution time, and can come to zero bit error rate in some testing models. The robustness of watermark is also better than Ohbuchi’s method. Besides, we proposed a data embedding algorithm that it could embed digital image into polygonal models. The embedding data is no longer restricted to the bit stream that only consists of zero or one. The result of visualization or quantification of appearance between the cover model and the stego model or between original image and the extracted image are almost the same. It comes to the purpose of information hiding adequately. We consider that efficient watermarking algorithm for polygonal models and data embedding algorithm have concrete contribution to subjects of three-dimensional watermarking and information hiding.

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Peng, Yu-Cheng, and 彭玉成. "Hardware implementation of watermarking using minimum error embedding algorithms." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/31413323029809659364.

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碩士 國立聯合大學 電子工程學系碩士班 98 This paper presents the novel multi-bit bitwise adaptive embedding algorithms for watermarking and data hiding. These embedding algorithms can embed multi-bit (k-bit,k≧1 ) secret data into cover data only introduce minimum embedding error no more than ±（2k-1-1）2i-k according to the embedding location i. To achieve such a goal, the proposed embedding algorithms adaptively evaluate the most similar value to replace the original one and which can be divied into three steps: (1) embed logo data into cover data, (2) adaptively adjust the least-significant bits (LSBs) of cover data, and (3) adaptively adjust the maximum-significant bits (MSBs) of cover data. The proposed embedding algorithms are not only achieving minimum error but also suitable to hardware implementation due to it is based on logic, algebraic, and bit operations. Many simulations show that the proposed embedding algorithms perform good embedding quality for watermarking and steganography applications. Keyword：Data hiding、LSB、Hardware implementation、Minimum error、Watermarking、Steganography

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Huang, Hsiang-Cheh, and 黃祥哲. "Genetic-Based Algorithms for Image Compression Classification and Watermarking." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/64643029870712063018.

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博士 國立交通大學 電子工程系 89 The purpose of this thesis is to modify and implement several optimization techniques so that they can be applied to a few valuable applications and improve their performance. In addition, with the widespread use of the Internet, copyright protection is becoming an important issue. Therefore, another subject of this thesis is to propose new and effective watermarking schemes. These schemes have been tested with simulated attacks. Combining the concepts of optimization and digital watermarking, we are able to enhance the robustness of watermarks by using the optimization techniques. In the first part of this thesis, we use four popular optimization techniques, namely, the genetic algorithms, simulated annealing, tabu search, and maximum descent algorithms, to improve vector quantizer design algorithm and the pattern classification schemes. Simulation results indicate that our new schemes have better performances compared to the conventional methods. In the second part, we focus on the design and modification of the digital data hiding algorithms. Digital data hiding means embedding additional information, which can be watermark for ownership identification, into the original multimedia data (text). In the copyright application, if the copyright owner can extract the watermark from a suspected copy in question to see whether it is a legal copy. We propose and improve several new algorithms in data hiding for images, and the results show that our algorithms can survive certain types of attacks. Moreover, simulations also reveal that the performance of our algorithms is better than that of many existing algorithms. Finally, in the third part of this thesis, we combine the concepts of the previous two parts described above, and apply the optimization techniques to data hiding. Simulation results show that our system is not only producing the watermarked images with acceptable quality, it is also able to resist certain types of attacks.

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Huang, Chun-Hsiang, and 黃俊翔. "Implementation and Improvement of Some Digital Image Watermarking Algorithms." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/18506317794500715519.

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碩士 國立臺灣大學 資訊工程學研究所 87 With the rapid growth of electronic publishing industry, copyright protection of electronic documents has become quite important. Recently, digital watermark seems to be a potential solution to discourage unauthorized copying and illegal distribution of digital documents. A useful digital watermark should satisfy the following requirements:  Perceptual invisible after embedding  Robust against compression and common digital manipulation  Unambiguous after watermark extraction  Statistical undetectable In recent years, many digital watermarking techniques are developed for image data. Among these proposals, some approaches use spread-spectrum techniques, and others use perceptual or statistical models. In this paper, a Discrete Cosine Transform (DCT) based watermarking system and a Discrete Wavelet Transform (DWT) based multi-resolution watermarking system are implemented. These two systems are implemented according to [4]. In the following sections, briefings of these watermarking algorithms and performance analysis of each system will be presented. Details and difficulties during the real implementation will be included, too. In order to achieve better perceptual invisibility and robustness against various attacks, we proposed an genetic algorithm (GA) based watermark optimization algorithm for further performance improvement of the existing watermarking algorithms. In our approach, watermark embedding positions are simulated by chromosomes and several GA optimization operators such as reproduction, crossover, and mutation are used. For the purpose of easy implementation and verification, we choose the DCT based watermarking technique proposed in [4] to prove the effectiveness of our algorithm, since we have its source code. The experimental result shows that the proposed approach can effectively improve the quality of the watermarked image and the robustness of the embedded watermark against various image manipulations.

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Yang, Xiao-Qian, and 楊曉蒨. "Semi-fragile Watermarking Algorithms for Tamper Detection and Image Authentication." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/8m7z7b.

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碩士 國立中正大學 資訊工程研究所 103 In recent years, many fragile watermarking schemes for image authentication have been proposed to protect the integrity of digital images. The main application of fragile and semi-fragile watermarking is image and video content authentication. However, these schemes still yielded two problems. First, these schemes still yielded unsatisfactory image quality of the watermarked images and low accuracy of tamper detection. Second, the image is permanently distorted and cannot be recovered to its original version. To deal with these problems, we propose a fragile watermarking scheme for image authentication based on the combination of DWT, SVD and DCT algorithms and a reversible watermarking scheme for image authentication scheme in the DWT domain to achieve high accuracy of tamper detection, and complete reversibility while maintaining high image quality of watermarked images. In the first scheme, the feature coefficients are extracted and are used to embed the authentication code by using the quantization index modulation (QIM) process. To guarantee that the extracted authentication code is correct, the Gram-Schmidt process is used to adjust the feature coefficients. In the second scheme, authentication code is randomly generated and embedded into 2nd DWT low-frequency subbands of each image block. The experimental results demonstrated that the proposed scheme provides great quality watermarked images and achieves high accuracy of tamper detection under different attacks. In addition, the property of reversibility is quite important to some special fields, i.e., medical images, military images, and fine artwork.

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Lee, Jung-Che, and 李榮哲. "On the Robustness of VQ-Based Digital Image Watermarking Algorithms." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/93981573266611795809.

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碩士 國立暨南國際大學 資訊工程學系 94 The robustness of watermarking algorithm is discussed in the dissertation. Usually, the invisible watermark is embedded into an image for copyright protection, we analyze several embedding techniques and show the dominated factors related with the robustness of watermarking techniques VQ (vector quantization) watermarking plays a newly developed branch in digital watermarking research fields. The embedding process can be performed in spatial domain, transform domain, or mixed domain. The VQ based watermarking is a kind of embedding in spatial domain. According to the generating scheme of a codebook proposed in the literature, our experimental results show that the robustness of such watermarking method is not strong enough when the watermarked image was corrupted, such as JPEG compression, burring, cropping, and shaping image processing. Hence, in order to improve the robustness, we adapt the generating process of a codebook to have a more robust watermarking algorithm. Besides, we also propose a new editing way of codeword to improve the quality of watermarked image, but the robustness is decreased a little.

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Terzija, Nataša [Verfasser]. "Robust digital image watermarking algorithms for copyright protection / von Nataša Terzija." 2006. http://d-nb.info/982382553/34.

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Chiang, Yi-Lung, and 江奕龍. "Applications of Genetic Algorithms to Orthogonal Arrays Auto-Configuration and Watermarking." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/56999417010047802497.

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碩士 國立高雄第一科技大學 系統資訊與控制研究所 98 This thesis studies two different applications of genetic algorithm, which include application of genetic algorithms to orthogonal arrays auto-configuration and application of genetic algorithms to frequency domain watermarking. 　　Taguchi method could reduce the times and cost of experiments. It could also enhance the quality of products and reduce the variation of producing process. The Taguchi method has been widely used in every field. However, when using the Taguchi method, there are several details must be considered, such as the problem of the orthogonal arrays resolution. This thesis takes L16 two levels and L27 three levels orthogonal arrays, for example, collocating different numbers of factor and uses genetic algorithms to search for the optimal resolution. It could search for the best configuration position and help the user to accomplish factor configuration of the orthogonal arrays with high resolution. This could help the user become more convenient in planning the Taguchi experiment. In addition, the human resource cost and the experimental accuracy would be improved in particular. 　　The research of digital watermark concerns to the feature of slight changing images that naked eyes are unable to aware of it. It puts the watermark data into the digital images that are protected. This thesis used genetic algorithms to search for the best embedding position. The full image data to 8 × 8 pixels block cutting unit and training of each block. Finally merged into a matrix of the watermark embedding position, it is watermark embedding and captures the entire graph reference position. This method is more efficient in execution. Therefore, it could enhance the practicability of watermarking.

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Cho, Shan-Chi, and 卓珊琪. "Image Segmentation and Watermarking Hiding Algorithm." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/28135383290162357067.

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碩士 國立臺灣海洋大學 通訊與導航工程系 97 The developing of Internet and communication technologies is fast in recent years. The exchange and storage of information is convenience and the transmission of information is no longer limit of time and space. Nowadays the important information of digitization can not use the conventional ways of encryption to protect simply. The user can acquire the information to modify or duplicate easily. However, the information of digitization con be protected by algorithm such as watermarking or encryption. Consequently, how to prevent the transmission process by illegal destroying or misappropriating is an important issue. In this dissertation, we apply the image compression to steganoraphy of information data. It is major for the size of watermarking to fix the Discrete Wavelet Transform(DWT) and Vector Quantification(VQ). By the results of two hiding ways discuss and compare with the difference.

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Hsu, You-Hsiang, and 徐祐祥. "A Novel NSCT Domain Image Watermarking Algorithm." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/55bjem.

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碩士 國立臺灣科技大學 資訊工程系 100 Geometry invariant features have been employed in watermarking algorithms to enhance robustness. The most widely used feature is Scale Invariant Feature Transform (SIFT) which is able to resist against various image distortion, such as rotation, scaling and shifting. In this work, the input image is first decomposed into the high-pass and low-pass subband by Non-Subsampled Contourlet Tansform (NSCT). The binary watermark image is then embedded through SIFT features extracted from the low-pass subband. Experimental results have shown that the proposed method can efficiently resist various image attacks while maintain high image fidelity.

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Lin, Yueh, and 林岳. "The hardware implementation of reversible watermarking algorithm." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/46986343496854701574.

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Hsu, Ting-ming, and 許庭銘. "Block Authority Watermarking Algorithm with Self-embedding." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/90908746447379976716.

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碩士 國立臺灣科技大學 電機工程系 96 Recently, Authority Watermarking or Fragile Watermarking technology is the major technology for image integrity verification. This kind of method inserts checking code into the image invisibly; however, it provides a reliable way for manipulated detector. Nowadays, authority watermarking not only verifies image integrity but also provides other useful information such as error localization. In this thesis, we proposed a novel invisible fragile watermarking scheme referring public key watermarking algorithm and self embedding method. This scheme is capable of detecting any change made to an image including pixel values, image size, and Counterfeiting Attack. After detecting error, it is possible to recover portions of the error blocks from self-embedding information.

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Hao-Tang, Chan, and 詹皓棠. "A Reversilbe Fragile Watermarking Algorithm for Holograms." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/25156178043415384708.

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曾瀚逸. "A Watermarking Algorithm for Holographic Microscopy System Authentication." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/39241987327745926753.

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碩士 國立臺灣師範大學 資訊工程學系 101 A fragile watermarking algorithm for hologram authentication is presented in this paper. While providing high perceptual transparency, the proposed algorithm attains high performance detection to delivery errors and malicious tampering. In the proposed algorithm, the watermark is embedded in the discrete cosine transform (DCT) domain of a hologram without quantization. The distortion produced by the watermark can be controlled. It can be effectively lowered by enhancing the precision for storing the watermarked hologram pixels. Experimental results reveal that the proposed algorithm can be used as a filter for blocking polluted or tampered holograms from reconstruction.

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Liu, Chien-Cheng, and 劉建成. "A blind watermarking algorithm against image cropped attack." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/47590665226729204332.

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碩士 玄奘大學 資訊科學學系碩士班 95 Due to the rapid growth on computer science and Internet technology, it becomes easier to access or to disseminate digital multimedia through Internet and World Wide Web. Therefore, the protecting of intellectual property right is also getting more important. There are many researches in digital watermarking based on spatial domain and frequency domain. However, most of them embedded the watermark in the whole image, there is no way to extract the watermark from part of the image cropped from original. Therefore, we propose a new blind DWT-based image watermark and use the location tag to solve the cropped problem. We also use the error correcting code to improve the robustness of against lossy data compression. The experiment results show that the image protected via our method can extract the watermark if the location tag can be detected even suffer from cropped and image compression attack. For those images of containing subject, like portrait, our method provides more robustness for protecting intellectual property right.

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Wu, Ming-Yan, and 吳明彥. "Audio Watermarking Method Based on Modified Patchwork Algorithm." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/78761253988284692229.

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碩士 國立交通大學 資訊科學系 91 Since computer science and network are developed, many data can be digitized and stored in hard discs or compact discs. Those data include text, image, audio, etc. This paper focuses on audio data, and presents a good audio watermarking method based on modified patchwork algorithm. It can satisfy our requirement when we need to hide information in audio data. The kernel of proposed audio watermarking method is the modified patchwork algorithm. We used mathematical probability and statistics to analyze the proposed embedding function and found the significance of its parameters. This study assists us to detect the watermarks from audio data reasonably. From the experimental results, we know how to control the parameters inside the embedding function to gain more robust audio watermarks and keep high audio quality. Experimental results show that the proposed audio watermarks can be almost preserved after MP3 compression and common signal processing manipulations.

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Jassim, Taha D., Hussain Al-Ahmad, Raed A. Abd-Alhameed, and Ahmed M. N. Al-Gindy. "Two levels block based wavelet watermarking algorithm for still colour images." 2014. http://hdl.handle.net/10454/10656.

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No A robust watermarking technique is implemented for copyright protection. The proposed method is based on 2-level discrete wavelet transform (DWT). The embedded watermarking information is a mobile phone number including the international code. The first level of the DWT transformation is applied on 16×16 blocks of the host image. All the coefficients of the 8×8 low-low (LL1) first level sub-band are grouped into one matrix. The second level of the DWT is then applied to the grouped matrix from the first level transformation. The highest coefficient from the LL2 sub-band (4×4) is used for embedding the watermark information. The extracting process is blind since it does not require the original image at the receiver side. The distortion in the host image due to the watermarking process is minimal and the PSNR is greater than 60 dB. The proposed algorithm showed robustness against several attacks such as scaling, filtering, cropping, additive noise and JPEG compression.

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