Wide spread spectrum watermarking with side information and interference cancellation

Nowadays, a popular method used for additive watermarking is wide spread spectrum. It consists in adding a spread signal into the host document. This signal is obtained by the sum of a set of carrier vectors, which are modulated by the bits to be embedded. To extract these embedded bits, weighted correlations between the watermarked document and the carriers are computed. Unfortunately, even without any attack, the obtained set of bits can be corrupted due to the interference with the host signal (host interference) and also due to the interference with the others carriers (inter-symbols interference (ISI) due to the non-orthogonality of the carriers). Some recent watermarking algorithms deal with host interference using side informed methods, but inter-symbols interference problem is still open. In this paper, we deal with interference cancellation methods, and we propose to consider ISI as side information and to integrate it into the host signal. This leads to a great improvement of extraction performance in term of signal-to-noise ratio and/or watermark robustness.Comment: 12 pages, 8 figure

State-of-the-art application of artificial neural network in digital watermarking and the way forward

Several high-ranking watermarking schemes using neural networks have been proposed in order to make the watermark stronger to resist attacks.The ability of Artificial Neural Network, ANN to learn, do mapping, classify, and adapt has increased the interest of researcher in application of different types ANN in watermarking.In this paper, ANN based approached have been categorized based on their application to different components of watermarking such as; capacity estimate, watermark embedding, recovery of watermark and error rate detection. We propose a new component of water marking, Secure Region, SR in which, ANN can be used to identify such region within the estimated capacity. Hence an attack-proof watermarking system can be achieved

Combating rotation, dilation and translation in digital watermarking.

by Yeung Siu Wai.Thesis (M.Phil.)--Chinese University of Hong Kong, 2000.Includes bibliographical references (leaves 59-[62]).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 2 --- Background --- p.4Chapter 2.1 --- Properties of a digital watermarking system --- p.5Chapter 2.2 --- Digital watermarking in still images: Spatial-domain vs Frequency- domain --- p.7Chapter 2.3 --- Capacity in digital watermarking --- p.8Chapter 3 --- A watermarking system --- p.10Chapter 3.1 --- Implementation of a watermarking system --- p.10Chapter 3.1.1 --- Embedding watermark --- p.11Chapter 3.1.2 --- Detecting watermark --- p.14Chapter 3.2 --- Robustness testing on the watermarking system --- p.18Chapter 3.3 --- Geometric attacks to the watermark system --- p.18Chapter 3.3.1 --- "The three distortions: Translation, Dilation and Rotation" --- p.19Chapter 3.3.2 --- The commutative property of rotation and dilation --- p.25Chapter 3.3.3 --- Implementation of geometric transform --- p.25Chapter 4 --- General Defense on Geometric Distortions --- p.28Chapter 4.1 --- Special designed watermark --- p.29Chapter 4.1.1 --- Ring-shaped watermark --- p.29Chapter 4.1.2 --- Phase Taylor invariance --- p.30Chapter 4.1.3 --- "Rotation, dilation and translation invariant watermark" --- p.31Chapter 4.2 --- Distortion detection --- p.34Chapter 4.2.1 --- Brute-force method --- p.35Chapter 4.2.2 --- Interactive method --- p.37Chapter 5 --- Specific Defense in Geometric Distortions - Phase angle com- parison --- p.43Chapter 5.1 --- Translation Detection --- p.44Chapter 5.2 --- Dilation Detection --- p.46Chapter 5.3 --- Rotation Detection --- p.49Chapter 6 --- Further work --- p.54Chapter 6.1 --- Large scale distortion detection --- p.54Chapter 6.2 --- Mixed geometric distortions --- p.55Chapter 7 --- Conclusion --- p.57Bibliography --- p.5

Moment tabanlı normalleştirmeye dayalı sayısal görüntü damgalama yöntemleri

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu çalışmada Moment Tabanlı Görüntü Normalleştirme kullanılarak iki boyutlu ayrık dalgacık ve karmaşık dalgacık dönüşüm uzaylarında dayanıklı sayısal görüntü damgalama algoritmaları geliştirilmiştir. Önerilen damgalama algoritmalarında normalleştirme işlemi geometrik bozunumlara karşı dayanıklılığı sağlarken, damganın dalgacık uzayında eklenmesi gürültü, doğrusal ve doğrusal olmayan filtreleme, JPEG sıkıştırması gibi saldırılara karşı damganın dayanıklılığını arttırmıştır. İnsan görme sisteminin özellikleri göz önünde bulundurularak, eklenen damganın hem algısal saydamlık hem de dayanıklılık gereksinimlerini aynı anda sağlaması başarılmıştır. Sunulan yöntem literatürde sıklıkla kullanılan iki yöntemle karşılaştırılmıştır. Simülasyon sonuçları, önerilen yöntemin, JPEG ve JPEG2000 sıkıştırması, çeşitli geometrik dönüşümler ve bazı görüntü işleme saldırılarına karşı her iki yöntemden de daha iyi sonuçlar verdiğini göstermiştir. Daha sonra, normalleştirmenin damgalama kapasitesi üzerindeki etkisi Moulin ve Mıhçak tarafından önerilen bilgi-teorisi tabanlı kapasite kestirim yöntemi kullanılarak ayrık kosinüs ve dalgacık uzaylarında araştırılmıştır. Kapasite analizi sonuçları, görüntünün dönüşümündeki sıfır değerli katsayıların sayısının kapasiteyi belirlediğini göstermiştir. Normalleştirme işlemi bir görüntünün dönüşümündeki sıfır değerli katsayı sayısını arttırdığından, damgalama algoritmalarında ön işlem olarak kullanıldığında daha iyi kapasite kestirim sonucu vermektedir. Bir görüntünün dalgacık dönüşümündeki sıfır değerli katsayı sayısı DCT dönüşümündekinden daha fazla olduğundan kapasite önemli olduğunda dalgacık dönüşümünün tercih edilmesi gereklidir.In this study, robust digital image watermarking algorithms in two dimensional discrete wavelet and complex wavelet domains were developed by using the moment based image normalization. In the proposed methods, while the normalization provides robustness against geometrical distortions, the fact that watermark is added in the wavelet domain achieves immunity for attacks such a noise, linear and non-linear filtering and JPEG compression. That the watermark meets transparency and robustness requirements simultaneously was obtained by taking the properties of the human visual system into account. The proposed method was compared to two commonly used digital image watermarking algorithms. Simulation results have shown that the proposed method gives better results that both of the commonly used algorithms in term of various geometrical distortions and several image processing attacks. Then, the effects of the normalization on watermarking capacity in discrete cosine and wavelet domains were investigated by using the information theory based capacity estimation method developed by Moulin and Mıhçak. The results of the capacity analysis have demonstrated that transform coefficients sparsity of an image determines the capacity. Since the normalization process increases transform coefficients sparsity of an image , it results in better capacity estimates when it is used as a preprocessing step watermarking algorithms. As the wavelet models capture sparsity better than the DCT models, wavelet transform must be preferred when capacity is the main concern

Collusion-resistant fingerprinting for multimedia in a broadcast channel environment

Digital fingerprinting is a method by which a copyright owner can uniquely embed a buyer-dependent, inconspicuous serial number (representing the fingerprint) into every copy of digital data that is legally sold. The buyer of a legal copy is then deterred from distributing further copies, because the unique fingerprint can be used to trace back the origin of the piracy. The major challenge in fingerprinting is collusion, an attack in which a coalition of pirates compare several of their uniquely fingerprinted copies for the purpose of detecting and removing the fingerprints. The objectives of this work are two-fold. First, we investigate the need for robustness against large coalitions of pirates by introducing the concept of a malicious distributor that has been overlooked in prior work. A novel fingerprinting code that has superior codeword length in comparison to existing work under this novel malicious distributor scenario is developed. In addition, ideas presented in the proposed fingerprinting design can easily be applied to existing fingerprinting schemes, making them more robust to collusion attacks. Second, a new framework termed Joint Source Fingerprinting that integrates the processes of watermarking and codebook design is introduced. The need for this new paradigm is motivated by the fact that existing fingerprinting methods result in a perceptually undistorted multimedia after collusion is applied. In contrast, the new paradigm equates the process of collusion amongst a coalition of pirates, to degrading the perceptual characteristics, and hence commercial value of the multimedia in question. Thus by enforcing that the process of collusion diminishes the commercial value of the content, the pirates are deterred from attacking the fingerprints. A fingerprinting algorithm for video as well as an efficient means of broadcasting or distributing fingerprinted video is also presented. Simulation results are provided to verify our theoretical and empirical observations

Digital Watermarking of Images towards Content Protection.

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