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Song, Chunlin. "A robust region-adaptive digital image watermarking system." Thesis, Liverpool John Moores University, 2012. http://researchonline.ljmu.ac.uk/6122/.
Full textAbstract:
Digital image watermarking techniques have drawn the attention of researchers and practitioners as a means of protecting copyright in digital images. The technique involves a subset of information-hiding technologies, which work by embedding information into a host image without perceptually altering the appearance of the host image. Despite progress in digital image watermarking technology, the main objectives of the majority of research in this area remain improvements in the imperceptibility and robustness of the watermark to attacks. Watermark attacks are often deliberately applied to a watermarked image in order to remove or destroy any watermark signals in the host data. The purpose of the attack is. aimed at disabling the copyright protection system offered by watermarking technology. Our research in the area of watermark attacks found a number of different types, which can be classified into a number of categories including removal attacks, geometry attacks, cryptographic attacks and protocol attacks. Our research also found that both pixel domain and transform domain watermarking techniques share similar levels of sensitivity to these attacks. The experiment conducted to analyse the effects of different attacks on watermarked data provided us with the conclusion that each attack affects the high and low frequency part of the watermarked image spectrum differently. Furthermore, the findings also showed that the effects of an attack can be alleviated by using a watermark image with a similar frequency spectrum to that of the host image. The results of this experiment led us to a hypothesis that would be proven by applying a watermark embedding technique which takes into account all of the above phenomena. We call this technique 'region-adaptive watermarking'. Region-adaptive watermarking is a novel embedding technique where the watermark data is embedded in different regions of the host image. The embedding algorithms use discrete wavelet transforms and a combination of discrete wavelet transforms and singular value decomposition, respectively. This technique is derived from the earlier hypothesis that the robustness of a watermarking process can be improved by using watermark data in the frequency spectrum that are not too dissimilar to that of the host data. To facilitate this, the technique utilises dual watermarking technologies and embeds parts of the watermark images into selected regions of the host image. Our experiment shows that our technique improves the robustness of the watermark data to image processing and geometric attacks, thus validating the earlier hypothesis. In addition to improving the robustness of the watermark to attacks, we can also show a novel use for the region-adaptive watermarking technique as a means of detecting whether certain types of attack have occurred. This is a unique feature of our watermarking algorithm, which separates it from other state-of-the-art techniques. The watermark detection process uses coefficients derived from the region-adaptive watermarking algorithm in a linear classifier. The experiment conducted to validate this feature shows that, on average, 94.5% of all watermark attacks can be correctly detected and identified.
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Qi, Huiyan. "Human visual system based adaptive digital image watermarking." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27287.
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It is known that the fidelity of the image is inversely proportional to the robustness of the watermark. Therefore, there should be the trade off between fidelity for robustness and vise versa. Based on the new spatial masking we explored in this thesis, a new adaptive digital image watermarking method is proposed. It keeps the invisibility of the watermark and maintains its robustness at the same time. The new spatial masking is built according to the image features such as flat areas with big brightness or darkness, edges, and regions with high activities. With the same watermarking energy, the quality of water-marked image with this masking is much better than the one without it. We also propose using the weighted Peak Signal-to-Noise Ratio (wPSNR) to evaluate the image quality. The watermark is detected by the key-dependent method without knowing the original image information. In addition, we extend this proposed spatial masking to the Discrete Cosine Transform (DCT) domain by using the method of searching the extreme value of the quadratic function subject to the bounds on the variables.
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Chen, Bingwei. "Adaptive watermarking algorithms for MP3 compressed audio signals." Thesis, University of Ottawa (Canada), 2008. http://hdl.handle.net/10393/27963.
Full textAbstract:
MPEG-1 Layer 3, known as MP3, has generated a significant popularity for distributing digital music over the Internet. MP3 compresses digital music with high ratio while keeping high sound quality. However, copyright issue is raised because of illegal copy, redistribution and various malicious attacks.
Digital watermarking is a technology that allows users to embed some imperceptible data into digital contents such as image, movie and audio data. Once a watermark is embedded into the original MP3 signal, it can be used to identify the copyright holder in order to prevent illegal copy and to verify the modification from the original content.
This thesis presents two novel adaptive watermarking algorithms for MP3 compressed audio signals for copyright protection. Based on Human Auditory System, the proposed algorithms calculate the energy of the original audio signal and apply Gaussian analysis on MP3 frames to adaptively adjust the watermarking coefficients. Watermark is embedded adaptively and transparently during the MP3 compression. The first watermarking algorithm detects watermark based on Gaussian distribution analysis. To enhance the security of the watermark, the second watermarking algorithm embeds random watermark pattern and uses correlation coefficient to detect watermark. Both algorithms support blind watermark detection and perform well. The first algorithm is more robust while the second algorithm is more secure.
LAME 3.96.2 open source was used as standard ISO MP3 encoder and decoder reference in this study. The experimental results show that the proposed watermarking algorithms can work on a variety of audio signals and survive most common signal manipulation and malicious attacks. As expected, the watermarking algorithms provide superior performance on MP3 compression.
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Wang, Sha. "Digital Watermarking Based Image and Video Quality Evaluation." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23988.
Full textAbstract:
Image and video quality evaluation is very important. In applications involving signal transmission, the Reduced- or No-Reference quality metrics are generally more practical than the Full-Reference metrics. Digital watermarking based quality evaluation emerges as a potential Reduced- or No-Reference quality
metric, which estimates signal quality by assessing the degradation of the embedded watermark. Since the watermark contains a small
amount of information compared to the cover signal, performing accurate signal quality evaluation is a challenging task. Meanwhile,
the watermarking process causes signal quality loss.
To address these problems, in this thesis, a framework for image and video quality evaluation is proposed based on semi-fragile and adaptive watermarking. In this framework, adaptive watermark embedding strength is assigned by examining the signal quality
degradation characteristics. The "Ideal Mapping Curve" is experimentally generated to relate watermark degradation to signal
degradation so that the watermark degradation can be used to estimate the quality of distorted signals.
With the proposed framework, a quantization based scheme is first implemented in DWT domain. In this scheme, the adaptive watermark
embedding strengths are optimized by iteratively testing the image degradation characteristics under JPEG compression. This iterative process provides high accuracy for quality evaluation. However, it results in relatively high computational complexity.
As an improvement, a tree structure based scheme is proposed to assign adaptive watermark embedding strengths by pre-estimating the signal degradation characteristics, which greatly improves the
computational efficiency. The SPIHT tree structure and HVS masking are used to guide the watermark embedding, which greatly reduces the signal quality loss caused by watermark embedding. Experimental results show that the tree structure based scheme can evaluate image
and video quality with high accuracy in terms of PSNR, wPSNR, JND, SSIM and VIF under JPEG compression, JPEG2000 compression, Gaussian
low-pass filtering, Gaussian noise distortion, H.264 compression and packet loss related distortion.
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Sakr, Nizar. "Adaptive digital image watermarking based on predictive embedding and a dynamic fuzzy inference system model." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27171.
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A novel image watermarking scheme is introduced that consists of an adaptive watermarking algorithm based on a model of the Human Visual System (HVS) and a Dynamic Fuzzy Inference System (DFIS). This scheme relies on the DFIS to extract the human eye sensitivity knowledge using the HVS model. The DFIS and the HVS combined are used to adjust and select the appropriate watermark length as well as the watermarking strength for each pixel in an image. The main goal of the algorithm is to provide a more robust and imperceptible watermark. The primary contribution of this work is to present a unique approach to perform image-adaptive watermarking by introducing a dynamic fuzzy logic technique. This logic relies on the statistical distributions of the HVS-generated data in order to accurately approximate the relationship found between all properties of the human perceptual system. In addition, we introduce a Predictive Watermark Embedding (PWE) algorithm that exploits the average power of the frequency-domain image coefficients as well as the aforementioned DFIS model in order to insure that the watermark insertion process is adaptively and accurately performed in lower-frequency components and significant DCT coefficients. (Abstract shortened by UMI.)
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Dang, Hieu. "Adaptive multiobjective memetic optimization: algorithms and applications." Journal of Cognitive Informatics and Natural Intelligence, 2012. http://hdl.handle.net/1993/30856.
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The thesis presents research on multiobjective optimization based on memetic computing and its applications in engineering. We have introduced a framework for adaptive multiobjective memetic optimization algorithms (AMMOA) with an information theoretic criterion for guiding the selection, clustering, and local refinements. A robust stopping criterion for AMMOA has also been introduced to solve non-linear and large-scale optimization problems. The framework has been implemented for different benchmark test problems with remarkable results.
This thesis also presents two applications of these algorithms. First, an optimal image data hiding technique has been formulated as a multiobjective optimization problem with conflicting objectives. In particular, trade-off factors in designing an optimal image data hiding are investigated to maximize the quality of watermarked images and the robustness of watermark. With the fixed size of a logo watermark, there is a conflict between these two objectives, thus a multiobjective optimization problem is introduced. We propose to use a hybrid between general regression neural networks (GRNN) and the adaptive multiobjective memetic optimization algorithm (AMMOA) to solve this challenging problem. This novel image data hiding approach has been implemented for many different test natural images with remarkable robustness and transparency of the embedded logo watermark. We also introduce a perceptual measure based on the relative Rényi information spectrum to evaluate the quality of watermarked images.
The second application is the problem of joint spectrum sensing and power control optimization for a multichannel, multiple-user cognitive radio network. We investigated trade-off factors in designing efficient spectrum sensing techniques to maximize the throughput and minimize the interference. To maximize the throughput of secondary users and minimize the interference to primary users, we propose a joint determination of the sensing and transmission parameters of the secondary users, such as sensing times, decision threshold vectors, and power allocation vectors. There is a conflict between these two objectives, thus a multiobjective optimization problem is used again in the form of AMMOA. This algorithm learns to find optimal spectrum sensing times, decision threshold vectors, and power allocation vectors to maximize the averaged opportunistic throughput and minimize the averaged interference to the cognitive radio network.February 2016
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Al-Nu'aimi, Abdallah S. N. A. "Design, Implementation and Performance Evaluation of Robust and Secure Watermarking Techniques for Digital Coloured Images. Designing new adaptive and robust imaging techniques for embedding and extracting 2D watermarks in the spatial and transform domain using imaging and signal processing techniques." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4255.
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The tremendous spreading of multimedia via Internet motivates the watermarking as a new promising technology for copyright protection. This work is concerned with the design and development of novel algorithms in the spatial and transform domains for robust and secure watermarking of coloured images. These algorithms are adaptive, content-dependent and compatible with the Human Visual System (HVS). The host channels have the ability to host a large information payload. Furthermore, it has enough capacity to accept multiple watermarks.
Abstract
This work achieves several contributions in the area of coloured images watermarking. The most challenging problem is to get a robust algorithm that can overcome geometric attacks, which is solved in this work. Also, the search for a very secure algorithm has been achieved via using double secret keys. In addition, the problem of multiple claims of ownership is solved here using an unusual approach. Furthermore, this work differentiates between terms, which are usually confusing the researchers and lead to misunderstanding in most of the previous algorithms.
One of the drawbacks in most of the previous algorithms is that the watermark consists of a small numbers of bits without strict meaning. This work overcomes this weakness
III
in using meaningful images and text with large amounts of data. Contrary to what is found in literature, this work shows that the green-channel is better than the blue-channel to host the watermarks.
A more general and comprehensive test bed besides a broad band of performance evaluation is used to fairly judge the algorithms.
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Al-Nu'aimi, Abdallah Saleem Na. "Design, implementation and performance evaluation of robust and secure watermarking techniques for digital coloured images : designing new adaptive and robust imaging techniques for embedding and extracting 2D watermarks in the spatial and transform domain using imaging and signal processing techniques." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4255.
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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Uliani, Neto Mario. "Equalização e identificação adaptativas utilizando marca d'agua como sinal de supervisão." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259283.
Full textAbstract:
Orientadores: João Marcos Travassos Romano, Leandro de Campos Teixeira GomesDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-10T02:05:39Z (GMT). No. of bitstreams: 1 UlianiNeto_Mario_M.pdf: 12916890 bytes, checksum: 53ed98252c8c6c265c985346ceaeec4f (MD5) Previous issue date: 2008
Resumo: O objetivo deste trabalho é investigar o uso de uma marca d'água digital como sinal de referência na filtragem adaptativa supervisionada, aplicada aos problemas de equalização e identificação de canais. Ao contrário de métodos mais tradicionais, nos quais a comunicação é periodicamente interrompida para a transmissão de seqüências de treinamento, uma marca d'água é transmitida ininterruptamente, juntamente com o sinal de informação. Através da comparação entre o sinal recebido processado pelo filtro equalizador e a marca d'água original, ou entre o sinal recebido e a marca d' água processada pelo filtro identificador, os coeficientes deste filtro são continuamente adaptados para estimar e rastrear as características do canal ao longo do tempo. Tanto a transmissão de informação útil como a adaptação do filtro equalizador/identificador nunca são interrompidas. Para que o processo de detecção de uma marca d'água digital seja eficiente, é necessária a sincronização da marca no detector. Efeitos de dessincron}zação podem prejudicar a detecção, potencialmente inviabilizando a extração adequada da informação contida na marca d'água. Esta dissertação apresenta dois métodos de ressincronização para sistemas de filtragem empregando marca d'água. Ambos os métodos são baseados no uso de seqüências de treinamento embutidas na marca d'água e revertem os efeitos de uma ampla classe de ataques de dessincronização. No caso de sinais que apresentem uma interpretação sensorial (e.g. áudio, imagens, vídeo), a adição da marca d'água não deve causar distorção perceptível no sinal original. Propomos o uso de um modelo psicoacústico em conjunto com um algoritmo de conformação espectral para demonstrar a viabilidade do método quando aplicado a sinais de áudio. Resultados de simulações computacionais são apresentados para evidenciar o desempenho das propostas fr_nte a técnicas tradicionais de filtragem adaptativa supervisionada
Abstact: The objective of this work is to investigate the use of a digital watermark as a reference signal in supervised adaptive filtering, applied to the channel equalization and identification problems. Contrary to traditional adaptive methods, in which communication is periodically interrupted for the transmission of training sequences, a watermark is transmitted uninterruptedly, along with the information signal. By comparing the received signal and the watermark processed by the identification filter, or the received signal processed by the equalization filter and the original watermark, the coefficients of this filter are continuously adapted to estimate and monitor channel characteristics through time. Both the transmission of useful information and the adaptation of the identification/equalization filter are never interrupted. For the watermark detection process to be efficient, synchronization of the watermark in the detector is required. Desynchronization effects can reduce detection performance, potentially making impracticable the appropriate extraction of the information contained in the watermark. This dissertation presents two resynchronization methods for filtering systems using a watermark. Both methods are based on training sequences that are embedded in the watermark, and can reverse the effects of a large class of desynchronization attacks. The embedding of a watermark into signals with sensorial interpretation (e.g. audio, image, video) should not introduce noticeable distortion in the original signal. To achieve this when applying our method to audio signals, we propose the use of a psychoacoustic model with a spectral shaping algorithm. Simulation results are presented to illustrate the performance of the proposed method when compared to traditional supervised adaptive filtering techniques
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
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Su, Jun-Min, and 蘇俊銘. "An Adaptive Watermarking Technique." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/31253085829822073466.
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Zhuang, Fu-Kai, and 莊富凱. "New Image-Adaptive Watermarking Schemes." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/59190733430437598883.
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碩士國立中正大學
資訊工程研究所
88
In this study, new image-adaptive watermarking schemes are proposed. Here the watermark is a binary gray-level signal with bipolar distribution or a pseudorandom gray-level signal with Gaussian distribution, which is designed for use in the block-wise DCT (discrete cosine transform) domain, i.e., the host image is partitioned into equal-sized non-overlapped blocks. Each block is transformed by DCT and the watermark is embedded into the host image by modifying the DCT coefficients. Instead of embedding the watermark into certain DCT coefficients (low, medium, or high frequencies), in this study the watermark is image-adaptively embedded into the host image, i.e., more watermark information is embedded into the larger DCT coefficients of complex blocks, and vice versa. In the proposed schemes, to resolve the rightful ownership of an image, a one-way hash function is employed and the original (host) image is required so that the proposed schemes are non-invertible and each image owner has a private key. To improve the image quality of the watermarked image, the JND (just-noticeable distortion) concept of the human visual system (HVS) is employed in this study. JND expresses a critical distortion profile in the sense that if the distortion caused by the watermark is below the JND threshold at all points in time, space, or frequency, the distortion in the watermarked image is imperceptible by the human visual system (HVS). Using the original (host) image, as well as the difference of statistical properties, the means and the variances, of all the blocks within the original and watermarked images, the proposed schemes can recover the high-quality watermark from the watermarked image. Based on the experimental results obtained in this study, the performances of the proposed schemes are superior to that of some existing schemes for comparison.
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Ou, Hong-Yi, and 歐宏毅. "ADAPTIVE LOSSLESS VISIBLE DATA EMBEDDING WATERMARKING." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/55042802470256171122.
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碩士國立清華大學
資訊系統與應用研究所
96
In this paper, an adaptive lossless visible watermarking scheme for watermarking according to image quality is proposed. The proposed adaptive algorithm combines Pixel Value Mapping Algorithm (PVMA) and Pixel Position Shift Algorithm (PPSA). While embedding, not only the function chosen record but watermarking pattern is embedded. When extracting, the receiver is able to recover the original image and obtain the watermark. The security of the propose scheme is also discussed.
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Hsu, S. W., and 徐紹文. "Adaptive Algorithms for Bar Code-based Watermarking." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/49428772025800965248.
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碩士國立臺灣大學
電機工程學研究所
89
Base on Internet and computer generalization, it is more important for digital information usage and management, especially for protection of copyright. Watermarking is the one of practical solutions. It not only hides data imperceptibly, but also supports security. Both legal user and owner can acquire well indemnification. In the thesis, we offer bar code-based algorithms and gray-scale coding to approach still-image watermark. It is easy and flexible to embed/extract watermark without any adjuncts, and resists different attack with specific functions. With bar code system and open algorithm, it will be convenient for e-commerce and image application
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Tao, Chi-Chuan, and 陶啟川. "Blind Adaptive Shift Length Watermarking For Digital Images." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/02755367489292932513.
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碩士東海大學
資訊工程與科學系
93
In recent years, as a result of the development of the network and popularization of the multimedia information, watermark technology has been utilized for ensuring the copyright mainly method of digital information. This thesis proposed a new blind watermarking algorithm based on discrete cosine transform (DCT) for digital images. In the proposed method, the difference of DCT coefficients between the original information and watermarked information was calculated and used to determine the adjustment of watermarked DCT coefficients. The results show that the proposed watermark algorithm no only provides similar robust as previous watermarking investigations, but also improves the image quality of watermarked image and the information quantity of hiding ability. Moreover, the original image is unnecessary for acquiring the watermark. In the reconstruction procedure, only two bytes side information is required for digital image codec. The file size of watermarked JPEG compressed image approximates one without watermarking.
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Yang, Cheng-Han, and 楊承翰. "Video Adaptive Watermarking Technique Based on DCT Domain Approach." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/17100191056487638565.
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碩士國立清華大學
電機工程學系
95
With the development of digital technology and popularization of internet, digital information could be duplicated and spread easily. On the other hand, because anyone can copy, falsify and even forge any data they obtained, the digital content owners and creators suffer serious piracy. It is evident that copyright protection of digital content has become one of the most important subjects in current. To solve this problem, two principal technologies are developed. One is digital watermarking and the other is cryptography. Digital watermarking technique allows anyone to access the protected data, but only the valid owner can extract the information from the host data to authenticate the ownership by watermarking technique when the dispute about the copyright of data happened. On the other hand, cryptography systems permit only valid key holders to access encrypted data. However, data is no longer protected once it is decrypted. Therefore, the digital content could be watermarked and then encrypted by means of cryptography to improve the information security. Based on intellectual property attention in information era, how to protect the personal ownership is more and more important and necessary. Hence, in this thesis we address a digital video watermarking technique based on DCT approach to insert the message which possesses high transparency and slight distortion. The watermark is mainly embedded into the uncompressed domain by adjusting the correlation between DCT coefficients, and the watermark can be extracted without using the original video information. The proposed system consists of embedding process and extracting process. Both of them are adopted a pseudo 3D DCT to achieve this scheme. In this way, our approach can reduce the computational complexity and computational time efficiently. The secret embedding key is employed to assist in extracting watermark to enhance the system security. In this way, the embedded watermark can not be extracted even though the algorithm is broken. Furthermore, the proposed system provides a good elasticity of design by using the adjustable parameters. Finally, we compare our proposed system with anterior methods. The experimental results illustrate that the proposed scheme possessed higher transparency and robustness to against various, e.g. filtering, noise, luminance modifications, especially compression, than other methods.
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Chen, Chun-Hung, and 陳俊宏. "Adaptive Fragile Watermarking for Image Authentication and Tamper Restoration." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/80671405089088112377.
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博士國立中山大學
資訊工程學系研究所
103
With the revolution of digital technologies, many conveniences have been brought to our daily lives. For example, it becomes very easy to create, duplicate, transmit, or modify digital products. Accompanying such advance, however, unauthorized use, illegal copying, and malicious modification of digital products become serious problems. These problems highlight the importance of image content authentication and grew the demand of that. For image authentication, one of the solutions called exact authentication offers effective protection of the integrity of the image content. Exact image authentication embeds a fragile watermark in the image and the inserted watermark is destroyed as soon as the protected image is tampered with, hence the name fragile. This kind of techniques allow the detection of any change or tampering of a protected image, which may also have the additional capabilities to localize and restore the tampered regions in the image. In this research, the problem of image authentication is addressed and two fragile watermarking techniques are proposed. The first technique is developed specifically for grayscale images. The image is divided into blocks and each of them is DCT-transformed and then encoded with certain predefined patterns. An optimal selection is adopted to find the best pattern for each block. The second technique focuses on color images. The color image is also divided into blocks and the approximations of the luminance and chromatic channels of each block are calculated. In order to reduce the data size, a differential coding is used to encode the details of the luminance channel with variable sizes according to the characteristic of the block. The more important data are well protected by using the error correction coding (ECC) technique and the results are duplicated for the purpose of redundancy. Both of the above two techniques can identify and localize the tampered regions in the image. In addition, both of them can achieve very high image quality for the watermarked and recovered images.
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Huang, Pang-Hsuan, and 黃邦瑄. "Robust Image Watermarking Using Adaptive Structure Based Wavelet Tree Quantization." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/11850418393531094961.
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碩士國立暨南國際大學
電機工程學系
95
In this paper, we proposed a novel robust wavelet-tree based watermarking method by using structure-based quantization. First, we arrange wavelet-trees into super-trees. Secondly, the watermark bits are embedded into the super-trees by the proposed structure-based quantization method. According to these bits, the super-trees will be quantized into a significant structure. Compared to the unquantized super-tree, the quantized version has strong statistical character. Based on this character, the watermark bits could be extracted robustly from the attack of image distortion. Finally, we further proposed an adaptive method to increase the PSNR value. Compared with the proposed non-adaptive structure-based method, it increases PSNR about 3.21 dB. Compared with Wang et al. [17], it greatly increases PSNR about 5.83 dB. For the consideration of the capacity for embedding, the maximum number of watermark bits is also increased. Besides, the computation load is small. The experimental results show that the proposed watermarking using adaptive structure-based wavelet-tree quantization performs well in JPEG compression, filtering (Gaussian filter, median filter and sharpen) and geometric attacks (pixel shifting). In addition, it is also very robust to against the multiple watermark attack.
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Huang, Pang-Hsuan. "Robust Image Watermarking Using Adaptive Structure Based Wavelet Tree Quantization." 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0020-3007200700281000.
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周頤廷. "A Study on Adaptive Embedding Strength for Color Image Watermarking." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/65169647707383056602.
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碩士國立彰化師範大學
資訊工程學系
104
As the internet keeping developing, copyright protection of the digital contents has become more and more important. As a good solution to prevent malicious steals and attacks, digital watermarking has become very popular in recent years. This paper is investigated the effect of embedding strength setting. In our previous work, the embedding strength is fixed, regardless of the texture complexity of each individual host image. In this study, we propose a new scheme which calculates the embedding strength by counting the edge points in advance. The three components of a color image are separately transformed by discrete cosine transform (DCT) and the resulting intermediate frequency coefficients are selected for watermark embedding. Because each component exhibits different robustness against various attacks, an appropriate linear combination of three is adopted for the watermark extraction. Experimental results show that using a fixed-embedding-strength scheme, the resulting performance is not stable for all host images. Therefore, using adaptive embedding strength, we propose a digital watermarking method which provides not only nice image quality but also superior robustness against various attacks for all types of host images.
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Li, Ming-lun, and 李明倫. "Content-Adaptive Digital Watermarking in H.264/AVC for Video Authentication." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/74066841153398123078.
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碩士國立中央大學
資訊工程研究所
95
Digital contents have become increasingly popular nowadays due to their convenience of transferring and storage. In addition, the rapid growth of broadband networks and advanced coding technologies make creation and distribution of digital contents much easier and faster than ever. However, digital contents can be easily modified and the malicious tampering of data may change the meaning of contents. In this research, we propose a digital watermarking scheme under the framework of H.264/AVC. The watermark is embedded into video frames to ensure the correct frame order. Such attacks as frame dropping, swapping or insertion can be reflected from the unambiguous watermark detection. We use DC values of blocks as the features of the image, which can help determine whether a shot change occurs. The image hash value is calculated by content analysis and used to generate the watermark sequence. The watermarking scheme uses a human perceptual model to adjust the watermark energy so that the watermark robustness can be enhanced without degrading the visual quality. By integrating the watermarking approach with H.264/AVC, we can make the watermark embedding/detection be done in a very efficient manner. The content-analysis mechanism not only makes the watermark imperceptible but simplifies the watermark detection process. The experimental results show that the embedded watermark can survive transcoding processes such as changing quality parameters or the coding structure. Besides, the frame modification attacks will be revealed by the successful watermark extraction.
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柯朝輝. "Adaptive Image Watermarking Based on Human Visual System in Frequency Domain." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/56318367008984243354.
Full textAbstract:
碩士東海大學
資訊科學系
89
Due to the prevalence of Internet, the various information is digitizing rapidly and can be accessed easily. People can reproduce and manipulate these digital data without granting appropriate credit to the owner. Therefore, how to protect data on Internet is one the important issue owners should face. One promising solution for the copyright protection of digital images is a so-called watermarking technique. The watermarking technique can hide an invisible signature or code in digital image to indicate the owner or recipient. The current watermarking schemes can be classified into two categories: spatial domain approach and frequency domain approach. Although the frequency domain techniques are robust when various signal-processing attacks, it is difficult for them to evaluate visual imperceptibility. For the purpose of overcoming mention above, the method of simulating attack is adopted to simulate signal-processing operations that modify the grayscale value of the image in spatial domain. First, we use a just-noticeable distortion (JND) based on human visual model to check out the maximal intensity of simulating attack. The image operated by simulating attack is transformed to the frequency domain using discrete cosine transform (DCT) and then the change of amount for each frequency component is obtained. The change of amount is the maximal intensity, which each DCT coefficient can be embedded into suitable capacity of watermarking information. The choice of embedding the watermark into DCT coefficient is exactly depended on the three factors - the frequency position, the magnitude of DCT coefficient, and the amount of embedding information. Secondly, a dynamic watermarking technique is considered. The original image is divided into several non-overlapped blocks, and their corresponding block content feature is computed. According to the different content feature of each block, the maximal amount of watermarking information for each block is embedded into the original image. The multi-watermarking technique is another main point approached in this paper. We proposed a rule of complementary correction that can overcome the drawback of single watermarking technique limited by the similarity of watermark depended upon the amount of cropped image. The veracity of extracted watermark that we analyze depends upon the characteristics coming from the change of coefficient because of doing signal-processing operations. Then we can correct its watermark with help of the other groups. The small amount of cropped image caused by cropping attack can still be extracted of embedded watermark. In summary, our watermarking scheme applies human visual system to frequency domain and makes sure that embedded watermark into images is invisible in spatial domain. Besides, we proposed the location strength model and the rule of complementary correction to make the embedded watermark high in robustness to resist artificial attacks. Experiment results showed that the proposed scheme demonstrated good performance of robustness against signal-processing attacks, such as JPEG compression, cropping, adding noise and blurring.
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Lai, Ming-Shan, and 賴明姍. "Audio Watermarking System Based on Adaptive Wavelet Quantization Index Modulation Technique." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/gh332m.
Full textAbstract:
碩士國立中央大學
通訊工程研究所
94
In this paper, we propose a robust audio watermarking technique which adopts the wavelet QIM method with adaptive step sizes for blind watermark extraction. Since wavelet transform offers both temporal and frequency resolutions, it is suitable for audio signal processing. The original audio signal is first segmented and divided into 29 subbands via wavelet packet decomposition. The bandwidth allocation of the subband decomposition structure is close to the critical band structure of human auditory system. According to Psychoacoustic Model, middle-low subbands are chosen for watermark embedding. The adaptive step size technique is applied to audio signals with different characteristics based on the criterion that SNR must be maintained above 20 dB so that it is robust and transparent. We formulate the step size of each frame to be proportional to the magnitude of the audio signal. No side information on the step sizes need to be transmitted. We analyze the performance of the proposed algorithms in terms of data SNR and Normalized Correlation (NC). The experimental results show that the embedding capacity is around 4 bits/frame and the watermark is robust against MP3 compression at 64 Kbps, resampling, requantization, and Gaussian noise corruption. The NC values after attacks are all above 0.8 in the experiments so that the copyright can easily be distinguished.
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Chen, Tai-Wan, and 陳泰完. "Copyright Protection and Annotation with Reversible Data Hiding and Adaptive Visible Watermarking." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/19038175034948366169.
Full textAbstract:
碩士國立高雄應用科技大學
電子與資訊工程研究所碩士班
95
We propose a copyright annotation scheme with both the visible watermarking and reversible data hiding algorithms in this thesis. It is commonly encountered that visible watermarks are embedded on purpose in one corner of an image or video clips to annotate the copyright owner. It is usually asked by the buyer to remove the visible watermark to return to its original form who obtains such an image or video. In this thesis, we propose a method to combine both the visible watermarking algorithm, and reversible data hiding. Simulation results demonstrate the effectiveness and feasibility of our algorithm.
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Li, Wan-Chun, and 黎萬群. "Audio Watermarking via Integrating the Functionalities of the Adaptive QIM and SVM Classifier." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/94444911505079095279.
Full textAbstract:
碩士國立宜蘭大學
電子工程學系碩士班
101
The rapid development of digital technology has made the replication and manipulation of digital media more convenient. Such convenience may cause a lot of copyright problems because the media data can be rapidly distributed via Internet without legal authorization. To protect the intellectual property right, this thesis presents a novel digital audio watermarking technique, which embeds proprietary information firmly into digital audio signals to resolve the property disputes This thesis is going to address two issues. The first one is related to the computational framework consisting of discrete wavelet packet transform (DWPT) and discrete cosine transform (DCT). The employed framework takes advantage of the human auditory masking effect through the quantization index modulation (QIM) scheme so that a balance between the robustness and imperceptibility can be reached. As the developed technique recovers the watermarks without referring to original audio signals, it is a kind of blind audio watermarking technology with more complexities. The second issue discusses how to increase the robustness of embedded watermark based upon the aforementioned framework. Here the learning and classification characteristics of the support vector machine (SVM) are exploited to seek appropriate audio segments for watermarking. By means of training, the SVM can determine the resistance ability against malicious attacks for different frequency bands in each individual frame. During the process, we also use the BCH encoder, which renders an additional protection measure, to increase the watermark robustness. The performance of the developed audio watermarking technique has been evaluated using the perceptual evaluation of audio quality (PEAQ) and bit error rate (BER). Experimental results show that the average objective difference grade (ODG) obtained from the PEAQ is close to zero, which means that the watermarked and original audio signals are virtually distinguishable. In the test of common digital signal processing attacks, the accuracy rates of recovered watermark bits are all above 97%. Moreover, by employing the SVM to select the embedded segments, we can further enhance the accuracy by more than 20 percent.
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Wu, Pei-da, and 吳佩達. "A Recoverable Semi-Fragile Watermarking Scheme Using Cosine Transform and Adaptive Median Filter." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/4xzn9u.
Full textAbstract:
碩士大同大學
資訊工程學系(所)
95
We present a novel semi-fragile watermarking that can tolerate legitimate processes, and detect and recover tampered regions effectively. To achieve the above goals, the proposed scheme uses Discrete Cosine Transform (DCT) and an adaptive median filter. The proposed scheme includes two phases, one is watermarked image generation phase and the other is integrity verification phase. In the watermarked image generation phase, the scheme first divides the image into several non-overlapping blocks and calculates the average of each block as the feature. Then the scheme randomly selects the blocks for embedding each feature. Moreover, the features are embedded into the AC coefficients of the DCT domain. In the integrity verification phase, the current features of each block will be generated from the suspect image, and the previously embedded corresponding features will be extracted from the DCT domain for later verification. By comparing the currently generated features with the previously embedded features, the differences between them are obtained. Finally, the proposed scheme localizes the tampered regions according to the following rules. If the image is tampered by malicious attacks, such as cropping or counterfeit attack, the difference will result in cluster regions unlike the salt and pepper noises caused by JPEG compression. The experimental results prove the proposed scheme can withstand legitimate processes, such as JPEG compression, brightness adjustment, contrast adjustment, and sharpening. More importantly, the tampered regions are detected after filtering and effectively recovered using embedded watermark.
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Jian, Liang-Yih, and 簡良益. "A New Adaptive Wavelet-Based Watermarking Scheme with Robustness-Distortion Optimization and Error-Correction." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/84864171295422160987.
Full textAbstract:
碩士國立清華大學
資訊工程學系
87
With the progress in digital storage and transmission technology, digital data has become very popular, and the copyright issue is very important. Digital watermark embeds copyright information such as author declaration, version control, or CGMS (Copyright Generation Management System) into source data. It is a potential solution for copyright protection. The chief defect of watermarking is to decrease image quality. This is unacceptable especially for high quality digital source such as DVDs. It is hard to embed watermark without any defect of image quality when high robustness is required. Many researches address on HSV, affecting image data in a just-notified-defect sense. However, HSV is experimental and hard to find an objective model. Although image quality is important, there are still many applications that require strong robustness despite the image defect. Indeed, it is a trade-off between watermark robustness and image quality. In this thesis, we develop a complete scheme that takes watermark robustness or image quality as the constrained parameter and optimizes the other. The proposed watermarking scheme is based on wavelet transform. We embed copyright information into the best coefficient location in a rate-distortion sense. With the proposed algorithm, we can optimize the watermark robustness under the constrained image quality. On the other hand, we can optimize image quality under the watermark robustness constraint. Moreover, we encode the embedded information with error-correction coding. This adaptive and error-correction watermarking scheme is very suitable for CGMS in DVD II. The proposed algorithm takes advantages on three key concepts: (1) The hierarchical subband characteristics of wavelet transform (2) Rate-distortion theory in solving a constrained problem (3) Error-correction code for embedded information. Experimental result shows that our scheme will take good balance in watermark robustness with image quality.
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Yang, Bo-Zhi, and 楊博智. "Adaptive Spread Spectrum Digital Video Watermarking Embedding Technique Using Block-Based Discrete Wavelet Transform." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/cyqr7v.
Full textAbstract:
碩士國立嘉義大學
資訊工程學系研究所
95
The major goal of this study is to embed and detect a watermark for digital video. In general, the spatial watermark embedding technique can not obtain better robustness in comparison with other techniques. This study embeds watermark in spatial domain based on image block which contains features with high intensity, high texture, and high motion, and improves the robustness of the watermark embedded in spatial. Since human visual system (HVS) can’t sense variations caused by high brightness, high texture, and fast motion regions within the video frames, an adaptive watermarking technique was developed to embed watermark signals into these regions. To this end, a digital video is first divided into various frames consisting of several blocks. Each block is then transformed by discrete wavelet transform (DWT). Feature blocks are determined based on the image features discussed above. Spread spectrum incorporated with just notice difference (JND) is performed to embed the watermark into feature blocks or non-feature blocks. Because feature block was designed based on HVS, the watermark is imperceptible to human’s eyes. The embedded watermark can be detected only with a frame. The proposed can resist attacks of linear transformation in digital video frames including frame average, frame reduction, and frame shuttle. Experimental results also demonstrate that the proposed method can obtain better performance in comparison with traditional schemes and resist various malicious attacks for still images such as cropping, JPEG compression, MPEG compression, and etc..
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Sun, Duen-Wu, and 孫敦午. "On the Design of Adaptive Watermarking Based on Support Vector Machines for Color Images." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/25495590591365625829.
Full textAbstract:
碩士國立中正大學
通訊工程研究所
91
In this thesis, a novel digital watermarking technique based on support vector machines (SVMs) is proposed to protect copyrights for color images. The proposed technique can be called SVM-based Color Image Watermarking (SCIW). The SVM can be trained for an optimal hyperplane from the given training patterns composed of a watermark and the corresponding watermarked color image. Due to the adaptability of SVMs, the SCIW method is developed to retrieve the watermark. During the procedure of watermark retrieving, a watermark can be retrieved directly from a watermarked color image without information on the corresponding original color image. Numerous experimental results are shown to prove that the SCIW method possesses robustness and generalization against common image manipulations, such as blurring, lossy compression, noising, rotation, scaling, and sharpening.
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陳俊錡. "QR Code Digital Watermarking Based on DWT and DCT Conversion Combined with Adaptive Embedding Intensity Adjustment." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/yjsdj9.
Full textAbstract:
碩士國立宜蘭大學
電子工程學系碩士班
106
Nowadays information technology has been growing rapidly, and a good use of this technology makes human life more convenient. People can easily download various multimedia data, such as image, sound and video, via the network. While it is easy to copy and modify multimedia pieces in the digital era, the events of illegally plagiarizing other’s media work also occur frequently. Therefore, it is very important to safeguard information security and protect creator’s intellectual property. This thesis presents a digital watermarking scheme suitable for QR code images, where binary information is hidden in the hybrid domain jointly formed by the discrete wavelet transform (DWT) and discrete cosine transform (DCT). The incorporation of adaptive embedding into the watermarking scheme makes it possible to improve the efficiency. Both DWT and DCT can cast images from the spatial to spectral domain. DWT holds multiresolution analytical capability in space and frequency, while DCT is competent in portraying the energy distribution of frequency components. These characteristics can be exploited to identify suitable objects for watermarking applications. Binary embedding is implemented using a novel technique called progressive quantization index modulation (PQIM), which enhances the robustness of digital watermarks without affecting the visual quality. The robustness of the proposed watermarking scheme is evaluated using fifteen different attacks, consisting of JPEG compression, JPEG2000 compression, Gaussian noise, salt-and-pepper noise, median filtering, Gaussian lowpass filtering, scaling, rotation correction, cropping, and brightness adjustment. The performance is compared with those obtained from two other methods in the literature [25, 26]. Experiment results indicate that, except in the case of salt-and-pepper noise attack, the proposed scheme, which is designated as “DWT-DCT(4x4)”, can effectively resist most of the attacks (including JPEG compression and Gaussian noise).
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Chung, Cheng-Long, and 鍾政隆. "On the Design of Adaptive Image Watermarking Based on Human Visual System, Neural Networks, and Fuzzy Inference Systems." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/84876097539616276151.
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