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1
Barr, Mohammad. "Robust logo watermarking." Thesis, De Montfort University, 2018. http://hdl.handle.net/2086/16550.
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Digital image watermarking is used to protect the copyright of digital images. In this thesis, a novel blind logo image watermarking technique for RGB images is proposed. The proposed technique exploits the error correction capabilities of the Human Visual System (HVS). It embeds two different watermarks in the wavelet/multiwavelet domains. The two watermarks are embedded in different sub-bands, are orthogonal, and serve different purposes. One is a high capacity multi-bit watermark used to embed the logo, and the other is a 1-bit watermark which is used for the detection and reversal of geometrical attacks. The two watermarks are both embedded using a spread spectrum approach, based on a pseudo-random noise (PN) sequence and a unique secret key. Robustness against geometric attacks such as Rotation, Scaling, and Translation (RST) is achieved by embedding the 1-bit watermark in the Wavelet Transform Modulus Maxima (WTMM) coefficients of the wavelet transform. Unlike normal wavelet coefficients, WTMM coefficients are shift invariant, and this important property is used to facilitate the detection and reversal of RST attacks. The experimental results show that the proposed watermarking technique has better distortion parameter detection capabilities, and compares favourably against existing techniques in terms of robustness against geometrical attacks such as rotation, scaling, and translation.
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Ahmaderaghi, Baharak. "Image watermarking based on Shearlet transform." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.703885.
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This thesis is dedicated to investigating image watermarking techniques based on the recently proposed transform called 'Shearlet' as the watermark embedding domain. The aim is to obtain new levels of imperceptibility and robustness which lead to higher data hiding capacity. With this idea in mind, new image watermarking algorithms in the Discrete Shearlet Transform domain are developed. First, combined with state of the art spread spectrum embedding methodology, a new watermarking algorithm using DST is designed in order to obtain better performance. The system was tested using five common types of image attacks. The results indicated that a combination of DST and spread spectrum embedding was more rQbust and more imperceptible compared with two well-known watermarking systems based on OCT and DWT domain, using the same embedding strategy. Second, a new perceptual image watermarking scheme using discrete Shearlet transform was developed by adapting a spatial visual model to the structure of the DST decompositions. The system performance was compared, under the same condition using the same embedding and extracting strategy with two watermarking systems based on DWT and DTCWT domain. Experimental results show the proposed method's efficiency by having higher imperceptibility and capacity and, at the same time, being more robust against some of the attacks. Finally, a Shearlet transform-based watermarking framework is proposed for blind watermarking, improving the other transformed-based methods. In order to develop this blind watermarking system, statistical modelling was applied to describe the behaviour of discrete Shearlet transform coefficients based on different sub-bands and resolutions. In order to investigate system performance, the obtained results are compared with watermarking systems based on DWT using the same embedding strategy. The overall results indicate the improvements in performance in order to assess the claims made during this research about the usage of the Discrete Shearlet Transform as a new embedding domain.
3
Khelifi, Fouad. "Image compression and watermarking in the wavelet transform domain." Thesis, Queen's University Belfast, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486229.
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This thesis is concerned with an investigation into novel image compression and watermarking techniques in the wavelet transform domain. Compression refers to the reduction in the representative bit-budget of data with an acceptable distortion. Such an application is widely encountered in our daily life as a requirement due to the rapid growth of digital multimedia technology that overwhelms the ca- .pacity of the available communication channels. Watermarking is the process of embedding a hidden pattern, called watermark, that represents the ownership of an authorized user into a host data. Watermarking systems are expected to play an important role in meeting at least two major challenges: Imperceptibility of the watermark and the robustness to intentional and unintentional data manipulations. Driven by the urgent need to protect digital media content that is being broadly distributed and shared through the Internet by an ever-increasing number of users, the field of digital watermarking has witnessed an extremely fast-growing development over the last decade. The first part of the thesis addresses the compression of digital images with state-of-the-art wavelet-based coders. Image compression is basically achieved by reducing the statistical redundancy existing within the data. The wavelet transform efficiently reduces such a redundancy and exhibits different attractive features exploitable by the most powerful coders available in the literature. In this thesis, we propose efficient extensions of the much celebrated scalable SPIRT coder to color and multispectral image compression. Also an efficient SPECK-based lossless coder is proposed for multispectral data. The idea is to adjust the algorithms in order to join each group of two consecutive bands as they show high similarities and strong correlation. In the second pat of this thesis, watermarking in the transform domain is addressed. Different transforms are considered and a number of the most efficient multiplicative watermark detectors are assessed. We show the advantages/disadvantages of each transform domain for watermarking in a comparative study. Also, an essential enhancement is introduced to the optimum detection rule which is shown to be more accurate and efficient. An adaptive watermarking technique is also proposed in the wavelet transform domain that exploits the characteristics of the human visual system. It is. shown to outperform the conventional wavelet-based technique. Finally, watermarking in the compressed domain is discussed and a new robust watermarking scheme in the SPIRT-compressed bit-stream is presented.
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Brannock, Evelyn R. "Using the Discrete Wavelet Transform to Haar'd Code a Blind Digital Watermark." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/cs_diss/35.
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Safeguarding creative content in a digital form has become increasingly difficult. It is progressively easier to copy, modify and redistribute digital media, which causes great declines in business profits. For example, the International Federation of the Phonographic Industry estimates that in 2001 the worldwide sales of pirated music CDs were 475 million US dollars. While a large amount of time and money is committed to creating intellectual property, legal means have not proven to be sufficient for the protection of this property. Digital watermarking is a steganographic technique that has been proposed as a possible solution to this problem. A digital watermark hides embedded information about the origin, status, owner and/or destination of the data, often without the knowledge of the viewer or user. This dissertation examines a technique for digital watermarking which utilizes properties of the Discrete Wavelet Transform (DWT). Research has been done in this field, but which wavelet family is superior is not adequately addressed. This dissertation studies the influence of the wavelet family when using a blind, nonvisible watermark in digital media. The digital watermarking algorithm uses a database of multiple images with diverse properties. Various watermarks are embedded. Eight different families of wavelets with dissimilar properties are compared. How effective is each wavelet? To objectively measure the success of the algorithm, the influence of the mother wavelet, the imperceptibility of the embedded watermark and the readability of the extracted watermark, the Peak Signal-to-Noise Ratio and the Image Quality Index for each wavelet family and image are obtained. Two common categories of digital watermarking attacks are removing the watermark and rendering the watermark undetectable. To simulate and examine the effect of attacks on the images, noise is added to the image data. Also, to test the effect of reducing an image in size, each image containing the embedded watermark is compressed. The dissertation asks the questions: “Is the wavelet family chosen to implement the algorithm for a blind, nonvisible watermark in digital images of consequence? If so, which family is superior?” This dissertation conclusively shows that the Haar transform is the best for blind, non-visible digital watermarking.
5
Haque, S. M. Rafizul. "Singular Value Decomposition and Discrete Cosine Transform based Image Watermarking." Thesis, Blekinge Tekniska Högskola, Avdelningen för för interaktion och systemdesign, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-5269.
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Rapid evolution of digital technology has improved the ease of access to digital information enabling reliable, faster and efficient storage, transfer and processing of digital data. It also leads to the consequence of making the illegal production and redistribution of digital media easy and undetectable. Hence, the risk of copyright violation of multimedia data has increased due to the enormous growth of computer networks that provides fast and error free transmission of any unauthorized duplicate and possibly manipulated copy of multimedia information. One possible solution may be to embed a secondary signal or pattern into the image that is not perceivable and is mixed so well with the original digital data that it is inseparable and remains unaffected against any kind of multimedia signal processing. This embedded secondary information is digital watermark which is, in general, a visible or invisible identification code that may contain some information about the intended recipient, the lawful owner or author of the original data, its copyright etc. in the form of textual data or image. In order to be effective for copyright protection, digital watermark must be robust which are difficult to remove from the object in which they are embedded despite a variety of possible attacks. Several types of watermarking algorithms have been developed so far each of which has its own advantages and limitations. Among these, recently Singular Value Decomposition (SVD) based watermarking algorithms have attracted researchers due to its simplicity and some attractive mathematical properties of SVD. Here a number of pure and hybrid SVD based watermarking schemes have been investigated and finally a RST invariant modified SVD and Discrete Cosine Transform (DCT) based algorithm has been developed. A preprocessing step before the watermark extraction has been proposed which makes the algorithm resilient to geometric attack i.e. RST attack. Performance of this watermarking scheme has been analyzed by evaluating the robustness of the algorithm against geometric attack including rotation, scaling, translation (RST) and some other attacks. Experimental results have been compared with existing algorithm which seems to be promising.<br>Phone number: +88041730212
6
Ahmed, Elmousalami Ayman Mansour Tawfik. "Digital image watermarking using fuzzy logic and naturalness preserving transform /." Search for this dissertation online, 2004. http://wwwlib.umi.com/cr/ksu/main.
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Chakravarthy, Chinna Narayana Swamy Thrilok. "Combinational Watermarking for Medical Images." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5833.
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Digitization of medical data has become a very important part of the modern healthcare system. Data can be transmitted easily at any time to anywhere in the world using Internet to get the best diagnosis possible for a patient. This digitized medical data must be protected at all times to preserve the doctor-patient confidentiality. Watermarking can be used as an effective tool to achieve this.
In this research project, image watermarking is performed both in the spatial domain and the frequency domain to embed a shared image with medical image data and the patient data which would include the patient identification number.
For the proposed system, Structural Similarity (SSIM) is used as an index to measure the quality of the watermarking process instead of Peak Signal to Noise Ratio (PSNR) since SSIM takes into account the visual perception of the images compared to PSNR which uses the intensity levels to measure the quality of the watermarking process. The system response under ideal conditions as well as under the influence of noise were measured and the results were analyzed.
8
Mendoza, Jose Antonio. "Hardware and Software Codesign of a JPEG2000 Watermarking Encoder." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9752/.
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Analog technology has been around for a long time. The use of analog technology is necessary since we live in an analog world. However, the transmission and storage of analog technology is more complicated and in many cases less efficient than digital technology. Digital technology, on the other hand, provides fast means to be transmitted and stored. Digital technology continues to grow and it is more widely used than ever before. However, with the advent of new technology that can reproduce digital documents or images with unprecedented accuracy, it poses a risk to the intellectual rights of many artists and also on personal security. One way to protect intellectual rights of digital works is by embedding watermarks in them. The watermarks can be visible or invisible depending on the application and the final objective of the intellectual work. This thesis deals with watermarking images in the discrete wavelet transform domain. The watermarking process was done using the JPEG2000 compression standard as a platform. The hardware implementation was achieved using the ALTERA DSP Builder and SIMULINK software to program the DE2 ALTERA FPGA board. The JPEG2000 color transform and the wavelet transformation blocks were implemented using the hardware-in-the-loop (HIL) configuration.
9
Brannock, Evelyn. "Using the discrete wavelet transform to Haar'd code a blind digital watermark." Atlanta, Ga. : Georgia State University, 2009. http://digitalarchive.gsu.edu/cs_diss/35/.
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Thesis (Ph. D.)--Georgia State University, 2009.<br>Title from title page (Digital Archive@GSU, viewed July 20, 2010) Michael Weeks, committee chair; Saeid Belkasim, Robert Harrison, Ephraim McLean, committee members. Includes bibliographical references (p. 145-153).
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Van, Huyssteen Rudolph Hendrik. "Comparative evaluation of video watermarking techniques in the uncompressed domain." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71842.
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Thesis (MScEng)--Stellenbosch University, 2012.<br>ENGLISH ABSTRACT: Electronic watermarking is a method whereby information can be imperceptibly
embedded into electronic media, while ideally being robust against common signal
manipulations and intentional attacks to remove the embedded watermark. This
study evaluates the characteristics of uncompressed video watermarking techniques
in terms of visual characteristics, computational complexity and robustness against
attacks and signal manipulations.
The foundations of video watermarking are reviewed, followed by a survey of
existing video watermarking techniques. Representative techniques from different
watermarking categories are identified, implemented and evaluated.
Existing image quality metrics are reviewed and extended to improve their performance
when comparing these video watermarking techniques. A new metric for
the evaluation of inter frame flicker in video sequences is then developed.
A technique for possibly improving the robustness of the implemented discrete
Fourier transform technique against rotation is then proposed. It is also shown that
it is possible to reduce the computational complexity of watermarking techniques
without affecting the quality of the original content, through a modified watermark
embedding method.
Possible future studies are then recommended with regards to further improving
watermarking techniques against rotation.<br>AFRIKAANSE OPSOMMING: ’n Elektroniese watermerk is ’n metode waardeur inligting onmerkbaar in elektroniese
media vasgelê kan word, met die doel dat dit bestand is teen algemene manipulasies
en doelbewuste pogings om die watermerk te verwyder. In hierdie navorsing
word die eienskappe van onsaamgeperste video watermerktegnieke ondersoek
in terme van visuele eienskappe, berekeningskompleksiteit en weerstandigheid teen
aanslae en seinmanipulasies.
Die onderbou van video watermerktegnieke word bestudeer, gevolg deur ’n oorsig
van reedsbestaande watermerktegnieke. Verteenwoordigende tegnieke vanuit verskillende
watermerkkategorieë word geïdentifiseer, geïmplementeer en geëvalueer.
Bestaande metodes vir die evaluering van beeldkwaliteite word bestudeer en uitgebrei
om die werkverrigting van die tegnieke te verbeter, spesifiek vir die vergelyking
van watermerktegnieke. ’n Nuwe stelsel vir die evaluering van tussenraampie flikkering
in video’s word ook ontwikkel.
’n Tegniek vir die moontlike verbetering van die geïmplementeerde diskrete Fourier
transform tegniek word voorgestel om die tegniek se bestandheid teen rotasie
te verbeter. Daar word ook aangetoon dat dit moontlik is om die berekeningskompleksiteit
van watermerktegnieke te verminder, sonder om die kwaliteit van die
oorspronklike inhoud te beïnvloed, deur die gebruik van ’n verbeterde watermerkvasleggingsmetode.
Laastens word aanbevelings vir verdere navorsing aangaande die verbetering van
watermerktegnieke teen rotasie gemaak.
11
Kim, Min-Su. "Wavelet transform based digital watermarking for 3-D surface meshes and mesh sequences." Lyon, INSA, 2007. http://theses.insa-lyon.fr/publication/2007ISAL0012/these.pdf.
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This thesis deals with digital watermarking methods for copyright protection of 3-D surface meshes and mesh sequences. The proposed methods are based on wavelet analysis of the geometry of the surface meshes, or on wavelet analysis of the vertex coordinate signals along the time axis. Static meshes. The first proposal embeds the watermark into the L2 norm of the geometric wavelet coefficients. The Cartesian coordinates should be converted into the spherical coordinates. For the invariance of the wavelet coefficients after inverse wavelet transform, it is necessary to synchronize the connectivity by re-ordering the vertex indexes from a reference vertex. This approach ensures the blind detection which does not require the original meshes during watermark extraction procedures. The second proposal is based on a statistical approach. The histogram of the L2 norm of scale coefficients was divided into regular bins. The mean or the variance of each bin is modified according to the watermark by a non-linear exponential transformation. The watermark can be extracted from the distribution of the scale coefficients after wavelet analysis, as well as from the distribution of vertex norms of the watermarked meshes without using the wavelet analysis. Mesh sequence with fixed connectivity. Our proposals are based on the vertex coordinate signals along the time axis. The watermark is incorporated into the wavelets coefficients of each coordinates or into the vertex norm signal wavelet coefficients or scales coefficients<br>Cette thèse propose des méthodes de protection des droits d’auteur, par tatouage numérique, d'objets en trois dimensions représentés par leur maillage triangulaire surfacique. Les approches proposées utilisent la décomposition en ondelettes du maillage ou des signaux associés à l’évolution des coordonnées des sommets de ce maillage au cours du temps. Maillages statiques. Une première proposition, incorpore le tatouage dans le module des coefficients d’ondelettes. Elle nécessite la transformation des coordonnées cartésiennes des sommets en coordonnées sphériques. Après la transformée en ondelettes inverse, les index des sommets sont réordonnés, afin d’assurer une invariance des coefficients d’ondelettes. Cette approche garantit l’extraction du tatouage sans le maillage original. Une deuxième proposition utilise une approche statistique. Elle incorpore le tatouage dans le module des coefficients d’échelles, par intervalles de leur histogramme. La moyenne ou la variance de chaque intervalle est modifiée par le tatouage à l’aide d’une transformation non linéaire exponentielle. Le tatouage peut être extrait, sans le maillage original, à partir de la distribution des coefficients d’échelle ou directement sur le maillage en pleine résolution. Séquences de maillages à connectivité constante. L'évolution temporelle des coordonnées des sommets est assimilée à trois signaux indépendants et le tatouage est incorporé dans les coefficients d’ondelettes de chacune des coordonnées, dans ceux du module de chaque sommet ou d'échelle de ce dernier signal
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Kim, Min-Su Prost Rémy Jung Ho-Youl. "Wavelet transform based digital watermarking for 3-D surface meshes and mesh sequences." Villeurbanne : Doc'INSA, 2007. http://docinsa.insa-lyon.fr/these/pont.php?id=kim_ms.
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Thèse doctorat : Traitement du Signal et Image : Villeurbanne, INSA : 2007. Thèse doctorat : Traitement du Signal et Image : Yeungnam University, Korea : 2007.<br>Thèse soutenue en co-tutelle. Titre provenant de l'écran-titre. Bibliogr. p. 119-127.
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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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Kong, I. Kuan. "Robust and high capacity digital image watermarking with discrete wavelet packet and cosing transform." Thesis, University of Macau, 2008. http://umaclib3.umac.mo/record=b1780397.
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Fei, Chuhong. "On the choice of transform for robust watermarking in the presence of lossy compression." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58791.pdf.
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Yang, Jianwei. "Construction of wavelets based on unitary transform, permutation and matrix extension with applications to watermarking." HKBU Institutional Repository, 2005. http://repository.hkbu.edu.hk/etd_ra/617.
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Okman, Osman Erman. "Quantization Index Modulation Based Watermarking Using Digital Holography." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607506/index.pdf.
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The multimedia watermarking techniques are evolved very quickly in the last years with the increase in the use of internet. The evolution of the internet makes the copyright issues very important and many different approaches are appeared to protect the digital content. On the other hand, holography is the method to store the 3-D information of an object but it is very applicable to use as a watermark because of the nature of the holographic data. The 3-D object can be reconstructed from the hologram even if the hologram is cropped or occluded. However, watermarking of an image with a hologram is a very novel approach and there are only a few works in the literature which are not very robust against the attacks like filtering or compression. In this thesis, we propose to embed the phase of the hologram to an image using quantization index modulation (QIM). QIM is utilized to make the watermarking scheme blind and degrade the host image as low as possible. The robustness of the proposed technique is also tested against several attacks such as filtering, compression, etc. The evaluated performance of this system is compared with the existing methods in the literature which uses either holograms or logos as the secret mark. Furthermore, the characteristics of the holograms are investigated and the findings about the hologram compression are reported in this work.
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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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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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Zenkevičiūtė, Irma. "Skaitmeninių vandens ženklų naudojimas paveikslėliuose." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110901_162834-83378.
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Būtinybė apsaugoti autorinių teisių savininkus nuo neteisėto intelektinės nuosavybės naudojimosi ir platinimo vis didėja. Tam puikiai tinka skaitmeniniai vandens ženklai, kurie ne tik apsaugo nuo neleistino intelektinės nuosavybės naudojimosi, bet pasinaudojus vandens ženklais galima susekti neteisėtą vartotoją. Šiame darbe aptarta diskrečioji kosinuso transformacija (angl. Discrete Cosine Transform (DCT)) ir išplėsto spektro (angl. Spread-Spectrum) ženklinimo vandens ženklais metodai, plačiau išnagrinėtas DCT metodas ir patikrinta keletas paprastų vaizdo atakų, kaip antai: karpymas, suspaudimas, pasukimas ir pan. Dalies vaizdo iškirpimas, pasukimas gali neatpažįstamai pakeisti vandens ženklą. Taip nutinka, nes iš pakeisto paveikslėlio ištraukiant vandens ženklą priešingu įterpimui metodu pasikeičia vaizdo taškų koordinatės, o iškirpus dalies koordinačių trūksta. Priklausomai nuo posūkio kampo ar iškirptos dalies dydžio sugadinamas ir vandens ženklas, kuris nepasikeičia keičiant spalvą ar kontrastą.<br>The necessity to protect copyright owners from using and sharing illegal intellectual property still grows. Digital water marks fits perfectly for this matter. They not only prevent using illegal intellectual property, but they can also detect illegal user. In this paper the discrete cosine transform (DCT) and spread-spectrum water-marking methods were discussed, and DCT method was analysed, and several image attacks were tested, such as: trimming, compression, rotation and etc. The trimming a part of an image, rotation of an image can change water mark beyond recognition. It happens because taking water mark out from changed image using inverse method of insertion image pixel coordinates change, and trimming causes a missing of part of coordinates. Depending on the angle of rotation or the size of a trimmed part a water mark is corrupted, but it does not change when a colour or a contrast is being changed.
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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.
Full textAbstract:
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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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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Číka, Petr. "Digitální vodoznačení obrazu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233465.
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Digital image watermarking has developed for the purpose of protecting intellectual property rights to multimedia data. The focus of this thesis is searching for an alternative solution of digital image watermarking methods. A detailed analysis of watermarking methods particularly in the frequency domain, and the modification of these methods are the main aim of this work. Improved performance in watermark extraction is one of the main goals. First, the common static image watermarking methods, possible attacks on the watermarked data and techniques for objective measurement of watermarked image quality are shortly introduced. Techniques which use the space domain for watermarking ar described in the next part of this work. It is about techniques which insert the watermark into the least significant bits of an image both in the RGB domain and in the YUV domain. The main part of the thesis depicts modified and newly developed static image watermarking methods in the frequency domain. These methods use various transforms and error-correction codes, by means of which the watermark robustness increases. All the methods developed are tested in MATLAB. Results together with tables and graphs are one part of work. The end of the thesis is devoted to a comparison of all the developed methods and their evaluation.
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Riad, Rabia. "Tatouage robuste d’images imprimées." Thesis, Orléans, 2015. http://www.theses.fr/2015ORLE2068/document.
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Le tatouage invisible d’images d’identité imprimées sur un support en plastique est un problème difficile qui intéresse le monde industriel. Dans cette étude, nous avons développé un algorithme de tatouage robuste aux diverses attaques présentes dans ce cas. Ces attaques sont liées aux processus d’impression/numérisation sur le support plastique ainsi qu’aux dégradations qu’une carte plastique peut rencontrer le long de sa durée de vie. La méthode de tatouage opère dans le domaine de Fourier car cette transformée présente des propriétés d’invariances aux attaques géométriques globales. Une méthode préventive consiste en un prétraitement de l’image originale avant le processus d’insertion qui réduit la variance du vecteur support de la marque. Une méthode corrective comporte deux contre-attaques corrigeant le flou et les variations colorimétriques. Pour une probabilité de fausse alarme de 10⁻⁴, nous avons obtenu une amélioration moyenne de 22% par rapport à la méthode de référence lorsque seule la méthode préventive est utilisée. La combinaison de la méthode préventive avec la méthode corrective correspond à un taux de détection supérieur à 99%. L’algorithme de détection prends moins de 1 seconde pour à une image de 512×512 pixels avec un ordinateur classique ce qui est compatible avec l’application industrielle visée<br>Invisible watermarking for ID images printed on plastic card support is a challenging problem that interests the industrial world. In this study, we developed a watermarking algorithm robust to various attacks present in this case. These attacks are mainly related to the print/scan process on the plastic support and the degradations that an ID card can encounter along its lifetime. The watermarking scheme operates in the Fourier domain as this transform has invariance properties against global geometrical transformations. A preventive method consists of pre-processing the host image before the embedding process that reduces the variance of the embeddable vector. A curative method comprises two counterattacks dealing with blurring and color variations. For a false alarm probability of 10⁻⁴, we obtained an average improvement of 22% over the reference method when only preventative method is used. The combination of the preventive and curative methods leads to a detection rate greater than 99%. The detection algorithm takes less than 1 second for a 512×512 image with a conventional computer, which is compatible with the industrial application in question
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Gourrame, Khadija. "Développement d'une technique robuste du tatouage des images aux attaques print-cam." Thesis, Orléans, 2019. http://www.theses.fr/2019ORLE3047.
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Le tatouage d’images numériques consiste à y insérer une marque d’une manière invisible à l’œil humain, cette marque pouvant être détectée par un algorithme de traitement d’images. Cela sert entre autres à établir la propriété de ce document numérique. Le but de cette thèse est de proposer une technique de tatouage d’image lorsque celle-ci est imprimée sur un support physique puis numérisé à main levée avec la caméra d’un smartphone. Cela permettra de proposer de nouvelles applications nomades de tatouage, comme par exemple le contrôle mobile de documents officiels contenant une photo d’identité (ID) que nous souhaitons développer. Dans ce cas, la marque doit résister aux attaques liées au processus d’impression/numérisation, dites attaques print-cam. Ces attaques très puissantes associent des modifications géométriques à des modifications de la valeur des pixels et peuvent rendre impossible la détection de la marque. La transformée de Fourier est utilisée comme domaine d’insertion de la marque, car cette transformée a des propriétés d’invariance contre certaines distorsions géométriques, rotation et translations dans le plan de l’image. La nouveauté de ce travail consiste à associer un tatouage d’image dans le plan de Fourier à 3 méthodes de correction : une correction géométrique de perspective basée sur la transformation de Hough, un filtre de Wiener pour réduire le flou et le bruit et enfin une correction colorimétrique pour réduire les dégradations de couleur. Les résultats obtenus sur des images ID montrent que la méthode proposée conduit à taux d’erreur total de 1%, contre 25% pour le meilleur de ses challengers. Ce taux d’erreur est compatible avec l’application sécuritaire visée<br>Digital image watermarking consists in embedding information within the image which cannot be seen by the human visual system, but recovered with a software. The aim of this thesis is to propose a watermarking method when the watermarked image is printed on a physical support and then read freehandedly with a smartphone camera. In order to survive to the print-cam process, the watermark must resist to multiple attacks. Those attacks occur during printing and capturing the image with a camera: in that case the captured image might be rotated around the optical axis of the camera producing 3D geometric deformation and translations and scaling may also occur. Pixel value distortions are also present. These attacks may cause the loss of synchronization of the watermark and make the detection impossible. Hence, the main objective of the thesis is to develop a watermarking method that is robust to the print-cam attack in the context of an industrial security application for ID images. Fourier transform is used as this watermarking domain has invariance properties against some geometric distortions. Three main correction methods were integrated to deal with print-cam attacks: frame-based perspective rectification of the freehandedly captured images using detection of Hough lines, a Wiener filter to decrease image blurring and reduce noise, and adjustments to reduce color degradations. Results show that the method is highly robust with a total error rate of 1%, compared to a least 25% of errors for other methods. the obtained error rate (1%) is being compatible with the targeted industrial application
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Earl, John William. "Image and video watermarking with overcomplete transforms." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613316.
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Ahmed, Kamal Ali. "Digital watermarking of still images." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/digital-watermarking-of-still-images(0dc4b146-3d97-458f-9506-8c67bc3a155b).html.
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This thesis presents novel research work on copyright protection of grey scale and colour digital images. New blind frequency domain watermarking algorithms using one dimensional and two dimensional Walsh coding were developed. Handwritten signatures and mobile phone numbers were used in this project as watermarks. In this research eight algorithms were developed based on the DCT using 1D and 2D Walsh coding. These algorithms used the low frequency coefficients of the 8 × 8 DCT blocks for embedding. A shuffle process was used in the watermarking algorithms to increase the robustness against the cropping attacks. All algorithms are blind since they do not require the original image. All algorithms caused minimum distortion to the host images and the watermarking is invisible. The watermark is embedded in the green channel of the RGB colour images. The Walsh coded watermark is inserted several times by using the shuffling process to improve its robustness. The effect of changing the Walsh lengths and the scaling strength of the watermark on the robustness and image quality were studied. All algorithms are examined by using several grey scale and colour images of sizes 512 × 512. The fidelity of the images was assessed by using the peak signal to noise ratio (PSNR), the structural similarity index measure (SSIM), normalized correlation (NC) and StirMark benchmark tools. The new algorithms were tested on several grey scale and colour images of different sizes. Evaluation techniques using several tools with different scaling factors have been considered in the thesis to assess the algorithms. Comparisons carried out against other methods of embedding without coding have shown the superiority of the algorithms. The results have shown that use of 1D and 2D Walsh coding with DCT Blocks offers significant improvement in the robustness against JPEG compression and some other image processing operations compared to the method of embedding without coding. The originality of the schemes enables them to achieve significant robustness compared to conventional non-coded watermarking methods. The new algorithms offer an optimal trade-off between perceptual distortion caused by embedding and robustness against certain attacks. The new techniques could offer significant advantages to the digital watermark field and provide additional benefits to the copyright protection industry.
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Grenier, Christophe. "Transformation de programme et protection de la propriété intellectuelle - préparation, intégration et vérification." Phd thesis, Ecole Polytechnique X, 2013. http://pastel.archives-ouvertes.fr/pastel-00915579.
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Dans le domaine de la Défense, les contrats export s'accompagnent souvent de transferts de technologie. Un compromis est donc nécessaire entre la protection de la propriété industrielle, celle du secret national et les demandes client. Nous étudierons dans ce contexte et au sein de DCNS les transformations de sécurisation de programme, principalement l'obfuscation et le watermarking. Nous présenterons ces transformations et les principaux résultats théoriques qui les concernent, ainsi que leur adéquation au besoin de sécurité. Nous étudierons la formalisation et la mise en oeuvre des principales techniques connues de transformations. Celles-ci ont pour objectif de rendre diffcile la rétro-ingénierie tout en préservant les fonctionnalités et les performances des systèmes. Nous aborderons les grandes familles existantes et leur implémentation à travers le bytecode Java. Ensuite, nous étudierons l'intégration de ces techniques dans le cycle de développement d'un logiciel complexe. Un premier focus sera effectué sur la mise en oeuvre de certaines techniques de transformation où leurs limites seront exhibées et des pistes d'amélioration proposées. Nous présenterons l'outillage réalisé pour cette analyse et les perspectives d'utilisation envisagées. Enfin, nous présenterons les mécanismes déployés en amont de la transformation permettant d'intégrer au plus tôt la gestion des contraintes et en aval pour vérifier que les techniques utilisées sont conformes à celles demandées afin de renforcer la confiance dans les transformations effectuées.
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Hwang, Jen-Jyh, and 黃仁志. "Digital Watermarking by Discrete Cosine Transform." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/99105407359663155102.
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碩士<br>世新大學<br>資訊管理學研究所(含碩專班)<br>98<br>With the rapid development and extensive use of multimedia and network technology, multimedia protection such as image, audio, video is an urgent issue. It has been widely concerned to view watermarking technology as a powerful tool for copyright protection and safety certification.
The paper is based on watermarks hiding creation by Discrete Cosine Transform (DCT) to analyze the robustness of the watermarked images. By not affecting the visually indistinguishable, this research hopes to provide bigger help for the area of watermarks hiding and digital documents.
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Ke, Jain-Yu, and 柯建羽. "Researches on Transform Domain Digital Watermarking." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/00617523742945649709.
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碩士<br>中原大學<br>電機工程研究所<br>99<br>As the technology improves, using the internet becomes more and more popular. We have made a big upgrading and improvement of the information quality and quantity transferred on the internet. When the digital data are communicated on the internet, hackers can easily and illegally copy the data and transfer them through the internet. If the data were not encrypted with extra protection, this will result in a violation of intellectual copyright for legal owners. Therefore, scientists proposed methods of adding digital watermarks to the data. Hiding the digital watermark in the multimedia (like videos, sounds, or pictures) can have a copyright protection.
This thesis studies invisible watermark embedding in the transform domain, which is a robust way to embed the watermark in the transform domain for resisting normal image attacks (such as image cropping, Gaussian noise addition, or filtering... etc). In the thesis, we focus on discussions of the discrete fractional random transform (DFRNT) and embedding the watermark in the DFRNT domain, which has better robustness as compare to other transforms (like discrete Fourier transform, or discrete cosine transform). In the Chapter 4 of the thesis, we discuss a lot of experiments with results and also propose a modified method to embed watermark in amplitudes of the transform domain.
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T, Mita Kumar. "Image adaptive watermarking using wavelet transform." Thesis, 2007. http://ethesis.nitrkl.ac.in/4393/1/Image_Adaptive_Watermarking_using_Wavelet.pdf.
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The availability of versatile multimedia processing software and the far-reaching coverage of the interconnected networks have facilitated flawless copying, manipulations and distribution of the digital multimedia (digital video, audio, text, and images). The ever-advancing storage and retrieval technologies have also smoothed the way for large-scale multimedia database applications. However, abuses of these facilities and technologies pose pressing threats to multimedia security management in general, and multimedia copyright protection and content integrity verification in particular. Although cryptography has a long history of application to information and multimedia security, the undesirable characteristic of providing no protection to the media once decrypted has limited the feasibility of its widespread use. For example, an adversary can obtain the decryption key by purchasing a legal copy of the media but then redistribute the decrypted copies of the original. In response to these challenges; digital watermarking techniques have been proposed in the last decade. Digital watermarking is the procedure whereby secret information (the watermark) is embedded into the host multimedia content, such that it is: (1) hidden, i.e., not perceptually visible; and (2) recoverable, even after the content is degraded by different attacks such as filtering, JPEG compression, noise, cropping etc. The two basic requirements for an effective watermarking scheme, imperceptibility and robustness, conflict with each other. The main focus of this thesis is to provide good tradeoff between perceptual quality of the watermarked image and its robustness against different attacks. For this purpose, we have discussed two robust digital watermarking techniques in discrete wavelet (DWT) domain. One is fusion based watermarking, and other is spread spectrum based watermarking. Both the techniques are image adaptive and employ a contrast sensitivity based human visual system (HVS) model. The HVS models give us a direct way to determine the maximum strength of watermark signal that each portion of an image can tolerate without affecting the visual quality of the image. In fusion based watermarking technique, grayscale image (logo) is used as watermark. In watermark embedding process, both the host image and watermark image are transformed into DWT domain where their coefficients are fused according to a series combination rule that take into account contrast sensitivity characteristics of the HVS. The method repeatedly merges the watermark coefficients strongly in more salient components at the various resolution levels of the host image which provides simultaneous spatial localization and frequency spread of the watermark to provide robustness against different attacks. Watermark extraction process requires original image for watermark extraction. In spread spectrum based watermarking technique, a visually recognizable binary image is used as watermark. In watermark embedding process, the host image is transformed into DWT domain. By utilizing contrast sensitivity based HVS model, watermark bits are adaptively embedded through a pseudo-noise sequence into the middle frequency sub-bands to provide robustness against different attacks. No original image is required for watermark extraction. Simulation results of various attacks are also presented to demonstrate the robustness of both the algorithms. Simulation results verify theoretical observations and demonstrate the feasibility of the digital watermarking algorithms for use in multimedia standards.
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Ko, Bo-Hur, and 柯柏合. "Discrete Wavelet Transform Based Audio Watermarking Development." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/66346272502898635565.
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碩士<br>國立暨南國際大學<br>電機工程學系<br>95<br>In this paper, we proposed a novel audio watermarking technique that the information is embedded into wavelet coefficients by modifying the amplitudes of entropy. The robust audio watermarking algorithm that utilizes the low frequency coefficients in DWT (discrete wavelet transform) as its guide to locate is proposed. The amount of modification to the amplitude is determined by the amount of distortion detected by the human ear. Unlike traditional usage, entropy plays the main role in the proposed watermarking technique. The performance of the proposed scheme in terms of SNR(signal to noise ratio) is analyzed. A relation between the number of consecutive coefficients and the SNR is presented. The experimental results show that the embedded data are robust against most common signal processing and attacks, such as MP3 compression, Gaussian noise, re-sampling, chopping and filtering.
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Chen, Yi-Ming, and 陳毅銘. "A Public Video Watermarking Techniquebased on Wavelet Transform." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/xybxh2.
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碩士<br>國立中央大學<br>資訊工程研究所<br>94<br>Watermarking is a technique to hide secret information in digital media. The information can prove ownership, identify a misappropriating person, trace the marked document’s dissemination through the network, or simply inform users about the rights holder or the permitted use of the media. Video watermarking introduces several issues which are not presented in image watermarking. Due to large amounts of data and inherent redundancy between video frames, video watermarking encounters many problems such as lost of watermark information, bad robustness, and etc.
In this paper, we proposed a video watermarking technique to protect multimedia data copyright by embedding a gray-level image as a watermark into a video. In the proposed method, a video is decomposed into several scenes; each scene consists of several image frames. The contextual energies of the video frame wavelet coefficients are computed to select embedding coefficients. The video frames are then embedded by watermarks in the larger-contextual energy wavelet coefficients.
The proposed video watermarking algorithm has the following advantages: (1) it allows blind retrieval of embedded watermark; that is, we need no original video to retrieve the watermarks; (2) the video image frames are converted to discrete wavelet transform (DWT), and embedded in DWT subbands makes watermarks perceptually invisible; (3) it is robust against the attack of frame dropping and scene dropping because of the watermark is embedded in each frames of the video; (4) it has higher imperceptible watermarked frames and more robust extracted watermarks by embedding watermarks in larger-contextual energy coefficients.
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Lin, Jih-Shun, and 林繼舜. "Invisible and Blind Watermarking Techniques with Wavelet Transform." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/34485546731907875062.
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碩士<br>國立清華大學<br>資訊工程學系<br>87<br>In the recent years, the growth of applications on network and multimedia techniques has become very popular. Because of such growth of network multimedia systems, how to protect the ownership has created a need for techniques that can be used for copyright protection of digital media. The image copyright protection involves the authentication of image ownership and can be used to identify illegal copies of images. One approach for image copyright protection is to introduce an invisible signal as a digital watermark in the image.
In this paper, we propose a wavelet-based invisible watermarking technique by a data structure based on the parent-child dependencies of subbands of images. This kind of parent-child dependencies of subbands of wavelet coefficients is applied to select significant blocks of wavelet coefficients to increase watermark robustness and reduce distortion. Another blind watermarking technique is proposed to embed the watermark and detect the embedded watermark in the wavelet domain without the information of the original image. Experimental results show that the invisible watermarking scheme is robust at the attack of the JPEG compression and various image procession techniques. The blind watermark extracting scheme can retrieve the embedded watermark successfully without the help of the original image after the JPEG and wavelet-based compression schemes even under very high compression ratio.
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Liu, Chi-sheng, and 劉啟昇. "Digital Audio Watermarking Utilizing Discrete Wavelet Packet Transform." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/55g4th.
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碩士<br>朝陽科技大學<br>網路與通訊研究所<br>92<br>The past few years have seen an explosion in the use of digital media. Editing the content of digital signals is easy, safe and economical. Thus, the rights of the author are endangered. The digital watermarking technique tries to solve the ownership problems and protect the copyright of the owner. In digital audio watermarking, the goal is to embed some meaningful message information in the original audio signal without perceptional distortion. Up to now, audio watermarking technique in frequency domain mostly takes advantage of Short Time Fourier Transform (STFT) to analyze the auditory masking effect. The STFT estimates spectrum in fixed window length during the whole audio signal. Furthermore, using longer window length obtains more complete frequency resolution certainly than fixed length, but leads to incomplete time resolution. In addition to the masking effect, there are many nonlinear properties in Human Auditory System (HAS). For instance, the resolution of low frequency in ear is more sensitive than high frequency. Therefore, the time-frequency resolutions are constant that can not react to the nonlinear properties. In this paper, we propose Discrete Wavelet Packet Transform (DWPT) to analyze masking effect efficiently. The idea is to employ dynamic and adaptive window length of analysis with the entire audio signal. Thus, the DWPT can not only improve on analysis of the nonstationary audio signal but also fit the frequency resolutions for the nonlinear properties in HAS. After embedding, the watermarked signal is robust enough to common audio processing such as cropping, shifting and MPEG audio compression. In the detection/extraction phase, the characteristic of autocorrelation function like the impulse function is employed to detect the watermark signal is existed or not. If it is, then the meaningful message can be extracted correctly from the watermarked signal without the original signal.
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莊永儒. "A Blind Watermarking Technique Based on Wavelet Transform." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/13799711462197124745.
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碩士<br>南台科技大學<br>電子工程系<br>92<br>Although the Internet allows us to make connections worldwide, download text, pictures, music and video at ease, digital information is often reproduced or modified without permission, causing problems such as the weakness of Internet security and invasion of intellectual property rights (IPR). The copyright holder often becomes the victim. Thus, the protection of IPR seems extraordinarily important.
The technique of digital watermarking system is helpful to identify the copyright of images. In this thesis, we proposed a novel watermarking system that is highly robust against attacks without perceptible image degradation. In addition, extracting a watermark without using the original image or memorizing the inserted position of the watermark can save huge space also extract the watermark conveniently. Besides, with the technique of toral automorphisms and the protection of password, the security of the watermark can be raised.
The resulting watermarking system has excellent performance. Experimental results confirm that the proposed method is extremely robust against JPEG compression, cropping, noises, and many other image processing.
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Hung, Tsung-Hua, and 洪宗樺. "A Study on Image Watermarking In Transform Domain." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/07216900490431507851.
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碩士<br>銘傳大學<br>資訊傳播工程學系碩士班<br>98<br>This paper presents an image watermarking algorithm based on integer wavelet transform (IWT) and discrete cosine transform (DCT). The proposed approach takes advantage of transform domain. IWT can recover the original image from its stego-image without any distortion and DCT can recover the original image from its stego-image with near perfect reconstruction from the stego-image. Both methods can extract the watermark perfectly. The algorithm hides 1bit of watermark into each block of IWT or DCT coefficients in the middle and high frequency subbands. The average of IWT coefficients of HL subbands or that of DCT coefficients of the selected middle and high frequency in each block is nearly zero. In order to enhance robustness of the proposed scheme, the watermark is pre-processed before embedding by employing random permutation and poly-phase sampling methods. Experimental results are provided to demonstrate the promising performance of the proposed algorithm.
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Mehrbany, Irany Behrang. "A High Capacity Reversible Multiple Watermarking Scheme - applications to Images, Medical Data, and Biometrics." Thesis, 2011. http://hdl.handle.net/1807/29530.
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Modern technologies have eased the way for adversaries to bypass the conventional identity authentication and identification processes; hence security systems have been developed to a great extent for protection of privacy and security of identities in different applications. The focus of this thesis is digital watermarking, security and privacy, as well as the ability to employ electrocardiogram as a method to enhance the security and privacy level. A high capacity reversible multiple watermarking scheme is introduced to mainly target the medical images. Furthermore, the use of ECG biometric signals in the form of the embedded watermark is studied. Experimental results indicate that the reversible data hiding scheme outperforms other approaches in the literature in terms of payload capacity and marked image quality. Results from the ECG mark embedding also show that no major degradation in performance is noticeable compared to the case where no watermarking is needed.
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Cheng, Wen-Chu, and 鄭文珠. "A Robust Watermarking Method on Discrete Cosine Transform Domain." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/07301667868891898797.
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碩士<br>國立清華大學<br>資訊工程學系<br>87<br>A novel image watermarking method with desired picture quality is proposed in this thesis. As usual, the watermark information is a long sequence of random values of normal distribution with zero mean and unity variance. The embedding process operates on the DCT domain as well as the spatial domain regarding the promotion of robustness and invisibility together. First, we understand that the quantity of embedding information is limited by the quantity of the corresponding DCT coefficient, especially for the low quantity coefficient the capability of robustness is declining. Conversely, it can sustain large quantity of information with pleasing level of robustness no matter how the postprocessing is done. Accordingly, our watermarking method adopts multiple and adaptive scaling factors to effectively embed the watermarking information with larger capacity relative to the other methods can do. These scaling factors are guided by desired image quality also. Besides, we superimpose a JND visual model on our method in spatial domain to guarantee the invisibility of watermarks. Furthermore, after the destructive postprocessing such as cropping or resizing, the current similarity measurement is useless. We propose an interesting similarity measurement that can truthfully reflect the similarity using the partial set of watermarks we only have. Finally, we conducted several experiments to justify the proposed method. The simulation results show that it surely prevent the original quality and against the JPEG compressing, cropping and resizing.
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Chien, Sheng-Lung, and 簡聖龍. "Multi-Purpose Image Watermarking Scheme Based on Wavelet Transform." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/06129497175587912547.
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碩士<br>南台科技大學<br>資訊工程系<br>96<br>In the recent years, the rapid development of network and multimedia technology makes it easier to access digital information, and circulation of digital image becomes very easy nowadays. Since the problems of harm to the author's rights become more serious than before, therefore, image authentication is an important and urgent issue to protect the intellectual property rights of digital image carried on Internet. Traditional watermarking schemes are mainly designed for either copyright protection or content authentication. Most existing watermarking schemes focus on one purpose, only a few multi-purpose image authentication schemes have been presented. Moreover, these methods focus on achieving the goals of both content authentication and copyright protection. Due to the semi-fragile watermarking methods become more and more important, we consider to propose a multi-purpose image authentication method with both semi-fragile image authentication and copyright protection. This method can be tolerated to JPEG and JPEG2000 compression, but sensitive to malicious attacks. At the same time, this method can verify ownership and identify the original owner.
This method is based on discrete wavelet transform (DWT) and we embed authentication information and watermark into original image. The authentication information is calculated from low frequency, and the watermark is generated from copyright information and standard deviation of coefficients in meddle frequency. Finally, we embedded these parts of information into the meddle-frequency of DWT domain. The experimental results show that our approach can locate the modified positions while authenticate the image. Simultaneously, it can verify ownership and identify original owner.
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魏國峰. "Watermarking Technique Based on Discrete Wavelet Transform and Subsampling." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/44458824835617514266.
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Lu, Cheng-Yu, and 呂承諭. "Robust Digital Watermarking based on Key-Dependent Image Transform." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/12484498832700648430.
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碩士<br>大葉大學<br>資訊工程學系碩士班<br>91<br>With rapid growth of multimedia, digital information and digital images are broadly transferring via internet but some of them are illegal. We can use digital watermarking technique to embed watermark in digital images to announce the copyright of the owner. Watermark embedded in frequency domain can resist the Jpeg compression, if the basis transform is public, hackers can use the same basis to extract the watermark from the frequency domain.
In this paper, we propose a key-dependent basis transform in our watermarking system in order to make the security high and make the watermark in the frequency domain can resist attack. We proposed a key-dependent and orthonormal basis transform in our watermarking system.
Since the basis functions or the key would be kept secrete, the watermark embedded in the transform domain is more robust and secure. To guarantee good robustness properties, the generated basis functions should have their energy concentrated mainly in low frequencies. Let the rows of the matrix H be arranged so that number of zero crossing increased with row number.
After experiments, our watermarking system under Jpeg compression attack and smooth attack has a good resistance.
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Zuo, Xiang-Yu, and 左翔宇. "Reversible Image Watermarking Approach with Variable Sized Wavelet Transform." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/53774563755433992084.
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碩士<br>玄奘大學<br>資訊管理學系碩士班<br>99<br>A reversible image watermarking approach recovers the original image from a watermarked image after extracting the embedded watermarks. This paper presents a wavelet coefficients based reversible image watermarking approach. The proposed method first calculates wavelet coefficients of the host image. Then each subimage is segmented to 8*8, 4*4 or 2*2 blocks according to their block structures. Then, the differences between central pixel and other pixels in each block are enlarged. At last, watermarks are embedded into LSB bits of above differences and then apply inverse wavelet transform to acquire the watermarked image. Experimental results show that the proposed variable block size method has higher capacity than conventional fixed block size method.
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C, Tzou H., and 鄒鴻昌. "Blind and Fragile Watermarking Technique Based on Discrete Wavelet Transform." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/58674112200770371303.
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Chen, Pin-Hong, and 陳品宏. "A Visible Watermarking Technique Using Saliency Map and Distance Transform." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/p5rt2j.
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碩士<br>元智大學<br>資訊工程學系<br>104<br>Visible watermarking is an intellectual property protection mechanism for digital images. It is fulfilled by stamping a visible logo and/or a segment of text on an image to declare the ownership of the image and to deter unauthorized usage to the image. Most visible watermarking techniques reported in the literature are based on characteristics of Human Visual System (HVS). These methods emphasis on displaying the watermark in uniform perceptual contrast to viewers; however, the clarity to the content underneath the watermark is not well maintained.
This thesis presents a visible watermarking technique which makes a compromise between exhibiting the watermark in uniform contrast and maintaining the fidelity to the original image. The proposed method combines the HVS characteristics, a saliency map and a distance transform function, to evaluate the stamping strength watermark pixels. Experimental results show the proposed method achieves a good balance to the visual quality between the watermark pattern and the image content beneath it.
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Chin-Kuen, Liang, and 梁晉坤. "Watermarking MPEG-4 2D Mesh Animation in the Transform Domain." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/95758203856279030329.
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碩士<br>國立臺北科技大學<br>資訊工程系碩士班<br>92<br>Digital watermarking techniques have been successfully applied to natural images and videos. On the other hand, the computer animation applied in virtual reality, cartoons, and movies may also need adequate copyright protection. In this thesis, we develop robust watermarking techniques for MPEG-4 2D mesh animation. We use several time-series transformation techniques, including discrete cosine transform (DCT), discrete wavelet transform (DWT), and singular spectrum analysis (SSA), to extract the spectral components of mesh movement. An invisible binary code watermark is added to the important components based on the spread-spectrum principle. At watermark extraction, a spatial-domain least-squares registration technique is used to restore the distorted mesh. A variety of attacks, including the affine transformation, smoothing, random noise, enhancement and attenuation, simplifying, and time warping, are used to verify the robustness of the proposed system. Experimental results show that our watermark system can withstand the aforementioned attacks. We also evaluate the time and storage complexity of the proposed watermarking system under different transformations.
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Hsu, Chai-Chen, and 許嘉真. "A watermarking scheme based on wavelet transform and modular operations." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/82675111890756322791.
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碩士<br>中國文化大學<br>資訊管理研究所<br>95<br>In this paper, a wavelet and modular based watermarking scheme is proposed. The variations of low frequency wavelet coefficients are computed to determine the coefficients which are suitable for watermark embedding. Then, the watermark is embedded by means of the modular operation. The experimental result shows that the difference between the host and the watermarked images cannot be discriminated with eyes easily. Besides, the watermark can also survive under several common attacks.
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Tzeng, PO-KO, and 曾博可. "A Robust Image Watermarking Technique Based on Discrete Wavelet Transform." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/46918268237081840400.
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碩士<br>義守大學<br>資訊工程學系<br>91<br>Because of the rapid development of Internet and the wide use of personal computer, people can easily obtain images via Internet, and then duplicate and modify the images. Digital watermarking can prove to be useful to avoid the illegal use of digital media. This paper presents a new DWT-based watermarking technique for still images that improves the robustness significantly with high transparency. First of all, the original image is transformed with DWT. The significant positions of DWT coefficients are then located for the embedding of watermark. The watermark is also transformed into DWT domain, and the lowest band is selected for embedding. We map the lowest-band watermark to a short-length chip that possess the feature of the original watermark. By duplicating the watermark chip several times, we obtain a new watermark sequence that has the error-correction capability. Using the majority vote decision, the decoder can correct errors due to attacks, thus raising robustness.
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Chang, Yu-Jen, and 張佑任. "A Dual Audio Watermarking Based on Fast Fourier Transform Technique." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/16354587991465062625.
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碩士<br>嶺東科技大學<br>資訊科技應用研究所<br>100<br>Internet makes our life more convenient, but with that comes some weaknesses:
such as easy duplication and the counterfeit; therefore, the intelligence proprietary protection becomes a critical issue. The digital watermarking technology can be used to prevent these weaknesses from occurring; also, most multimedia can have multiple ownerships, so, it’s a necessity to have dual copyright. This research proposes a dual audio watermarking technology that combines visual cryptography technology and Fast Fourier transform (FFT). The process transforms the audio into a frequency domain by FFT, then, uses the visual cryptography to generate two share images from two digital watermarking, then, embeds one share image into the frequency coefficients of the audio, finally, applies the inverse Fast Fourier transform (IFFT) to complete the dual
watermarked audio design. When verifying the ownership, the share image can be
extracted from the watermarked audio and verified the dual watermarking by applying the visual cryptography.