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Bis, Jan. "Řízení převíječky sádrokartonářské pásky (DWT)." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-316067.
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This thesis deals with a description of the industrial machine of the DWT (drywall tape) rewinder. The winder rewinds and cuts the drywall tape tape into smaller tapes, that are then sold. The first part contains a description of the winder, its structure and functions of its individual parts. The second part contains a description of the control system and the power wiring of winder. The next section contains a description of programming and setting of PLC, frequency inverters, and touch panel. Some modifications are then described when putting the winder into operation. The winder has been successfully implemented and built into a continuous shift operation. However, the development of the rewinder continues to improve its features and user-friendliness.
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Wichakool, Warit 1977. "A comparative study of DCT, LOT, and DWT-based image coders." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/86749.
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Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (leaves 108-109).
by Warit Wichakool.
M.Eng.and S.B.
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Kupka, Jan. "Vodoznačení digitálních dat." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217292.
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The main aim of this project is to implement two different types of the watermarking algorithm in frequency (transforamtion) domain. Because of the huge amount of the watermarking algorithms is this thesis dedicated to the watermarking methods in the frequency domain. These methods use kind of transformation implemented on the original data, the second step is modification of transformation coeficients. This project is dedicated to the methods which use discrete wavelet transformation. Nowdays the most popular transformation, which meets the best efforts. The aim of every method is to embeed the watermark into the original data so precisly, that none observer can recognize any change between the original and watermarked data. On the contrary, watermarked picture should be as resistant to the attacks as possible. By the term of attack, we understand all the ways, that disable watermark extraction. The watermark method robustness will be tested with the use of Checkmark program.
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Murugesan, Somasekar. "Benchmarking of Sleipnir DSP Processor, ePUMA Platform." Thesis, Linköpings universitet, Datorteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-74080.
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Choosing a right processor for an embedded application, or designing a new pro-cessor requires us to know how it stacks up against the competition, or sellinga processor requires a credible communication about its performance to the cus-tomers, which means benchmarking of a processor is very important. They arerecognized world wide by processor vendors and customers alike as the fact-basedway to evaluate and communicate embedded processor performance. In this the-sis, the benchmarking of ePUMA multiprocessor developed by the Division ofComputer Engineering, ISY, Linköping University, Sweden will be described indetails. A number of typical digital signal processing algorithms are chosen asbenchmarks. These benchmarks have been implemented in assembly code withtheir performance measured in terms of clock cycles and root mean square errorwhen compared with result computed using double precision. The ePUMA multi-processor platform which comprises of the Sleipnir DSP processor and Senior DSPprocessor was used to implement the DSP algorithms. Matlab inbuilt models wereused as reference to compare with the assembly implementation to derive the rootmean square error values of different algorithms. The execution time for differentDSP algorithms ranged from 51 to 6148 clock cycles and the root mean squareerror values varies between 0.0003 to 0.11.
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Ghosh, Debeshi D. "Audio Watermarking Using DWT Algorithm and Symmetric Key Cryptography." Thesis, California State University, Long Beach, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10263604.
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Watermarking is the process of embedding information into a carrier signal such as audio, video, and images. It is widely used to protect proprietary information in the signal to prevent information theft or duplicity. In this project, an audio watermarking system with dual layer security has been implemented. The entire system is divided into two sections that are independent, but have been combined, to make a unique system that provides increased levels of robustness. The first part of the project involves encrypting an embedded image (watermark) using the XOR method of symmetric key cryptography. Encryption is then followed by watermarking. The digital wavelet transform (DWT) algorithm was used to embed the encrypted image into an audio signal. This ensures that even if this image is removed during an attack to the carrier signal, it cannot be interpreted or used. Though encryption combined with watermarking is unconventional, it proves to be an effective technique when implemented correctly.
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Fontes, Ramiro C. "Applications of Allouba's Differentiation Theory and Semi-SPDEs." Kent State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=kent1271438954.
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Mei, Liming, and james mei@ieee org. "A DWT Based Perceptual Video Coding Framework - Concepts, Issues and Techniques." RMIT University. Electrical and Computer Engineering, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20090506.103244.
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The work in this thesis explore the DWT based video coding by the introduction of a novel DWT (Discrete Wavelet Transform) / MC (Motion Compensation) / DPCM (Differential Pulse Code Modulation) video coding framework, which adopts the EBCOT as the coding engine for both the intra- and the inter-frame coder. The adaptive switching mechanism between the frame/field coding modes is investigated for this coding framework. The Low-Band-Shift (LBS) is employed for the MC in the DWT domain. The LBS based MC is proven to provide consistent improvement on the Peak Signal-to-Noise Ratio (PSNR) of the coded video over the simple Wavelet Tree (WT) based MC. The Adaptive Arithmetic Coding (AAC) is adopted to code the motion information. The context set of the Adaptive Binary Arithmetic Coding (ABAC) for the inter-frame data is redesigned based on the statistical analysis. To further improve the perceived picture quality, a Perceptual Distortion Measure (PDM) based on human vi sion model is used for the EBCOT of the intra-frame coder. A visibility assessment of the quantization error of various subbands in the DWT domain is performed through subjective tests. In summary, all these findings have solved the issues originated from the proposed perceptual video coding framework. They include: a working DWT/MC/DPCM video coding framework with superior coding efficiency on sequences with translational or head-shoulder motion; an adaptive switching mechanism between frame and field coding mode; an effective LBS based MC scheme in the DWT domain; a methodology of the context design for entropy coding of the inter-frame data; a PDM which replaces the MSE inside the EBCOT coding engine for the intra-frame coder, which provides improvement on the perceived quality of intra-frames; a visibility assessment to the quantization errors in the DWT domain.
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Islam, Mohd Siblee. "A Decision Support System for StressDiagnosis using ECG Sensor." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-11769.
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Diagnosis of stress is important because it can cause many diseases e.g., heart disease, headache, migraine, sleep problems, irritability etc. Diagnosis of stress in patients often involves acquisition of biological signals for example heart rate, finger temperature, electrocardiogram (ECG), electromyography signal (EMG), skin conductance signal (SC) etc. followed up by a careful analysis of the acquired signals. The accuracy is totally dependent on the experience of an expert. Again the number of such experts is also very limited. Heart rate is considered as an important parameter in determining stress. It reflects status of the autonomic nervous system (ANS) and thus is very effective in monitoring any imbalance in patient’s stress level. Therefore, a computer-aided system is useful to determine stress level based on various features that can be extracted from a patient’s heart rate signals. Stress diagnosis using biomedical signals is difficult and since the biomedical signals are too complex to generate any rule an experienced person or expert is needed to determine stress levels. Also, it is not feasible to use all the features that are available or possible to extract from the signal. So, relevant features should be chosen from the extracted features that are capable to diagnose stress. Again, ECG signal is frequently contaminated by outliers produced by the loose conduction of the electrode due to sneezing, itching etcetera that hampers the value of the features. A Case-Based Reasoning (CBR) System is helpful when it is really hard to formulate rule and the knowledge on the domain is also weak. A CBR system is developed to evaluate how closely it can diagnose stress levels compare to an expert. A study is done to find out mostly used features to reduce the number of features used in the system and in case library. A software prototype is developed that can collect ECG signal from a patient through ECG sensor and calculate Inter Beat Interval (IBI) signal and features from it. Instead of doing manual visual inspection a new way to remove outliers from the IBI signal is also proposed and implemented here. The case base has been initiated with 22 reference cases classified by an expert. A performance analysis has been done and the result considering how close the system can perform compare to the expert is presented. On the basis of the evaluations an accuracy of 86% is obtained compare to an expert. However, the correctly classified case for stressed group (Sensitivity) was 57% and it is quite important to increase as it is related to the safety issue of health. The reasons of relatively lower sensitivity and possible ways to improve it are also investigated and explained.
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Sedlář, Karel. "Komprese genomických signálů pro klasifikaci a identifikaci organismů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220018.
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Modern classification of organisms is performed on molecular data. These methods rely on multiple alignment of sequences of characters which make them computationally demanding. Only small parts of genomes can be compared in reasonable time. In this paper, the novel algorithm based on conversion of the whole genome sequences to cumulative phase signals is presented. Dyadic wavelet transform is used for lossy compression of signals by redundant frequency bands elimination. Signal classification is then performed as a cluster analysis using Euclidian metrics where multiple alignment is replaced by dynamic time warping.
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SOUZA, MARCIO ALBUQUERQUE DE. "ARBITRARILY SHAPED OBJECT CODING USING SHAPE-ADAPTATIVE DWT AND SHAPE-ADAPTATIVE SPIHT." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2001. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=1748@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORCodificação de objetos de forma arbitrária extraídos de imagens regulares é um dos assuntos de maior desafio nos mais recentes padrões de codificação de vídeo (MPEG-4). Neste estudo, é proposta uma nova estratégia de codificação de objetos envolvendo maior eficiência na decomposição e quantização de sub-bandas. A técnica de transformação proposta envolve Transformada Wavelet Discreta (DWT) e a de quantização é baseada no algoritmo de Partição de Conjuntos em Árvores Hierárquicas (SPIHT).
Coding of arbitrarily shaped objects extracted from regular images is one of the most challenging issues on the latest video coding standards (MPEG-4). In this work, a new object coding strategy is proposed, involving greater efficiency on subband splitting and quantization. The proposed transform technique involves Discrete Wavelet Transform (DWT) and the proposed quantization technique is based on the Set Partitioning in Hierarchical Trees (SPIHT) algorithm.
La codificación de objetos de forma arbitraria extraídos de imágenes regulares es uno de los asuntos de mayor desafío en los más recientes padrones de codificación de video (MPEG-4). En este estudio, se propone una nueva estrategia de codificación de objetos con mayor eficiencia en la descomposición y cuantización de subbandas. La técnica de transformación propuesta incluye Transformada Wavelet Discreta (DWT) y la de cuantización tiene como base el algoritmo de Partición de Conjuntos en Árboles Jerárquicas (SPIHT).
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Bernardo, Luiz Carlos. "Sistemas de comunicação utilizando transmissão OFDM baseado em wavelets com subportadoras com modulação caótica." Universidade Presbiteriana Mackenzie, 2013. http://tede.mackenzie.br/jspui/handle/tede/1434.
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Previous issue date: 2013-06-14A chaotic signal based communication system represents a new wideband transmission model. Nonetheless, chaotic based systems have not yet shown a distinguished performance in terms of bit error rate when transmitted in narrow band channels or in the presence of impairments in comparison to the traditional communications systems. The focus of this work relies on an experiment that overcomes this issue, through the conjugation of the characteristics of traditional communications based in orthogonal carriers and those originated from chaotic signals. More clearly, the chaotic modulation is employed in sub-carriers of traditional OFDM (Orthogonal Frequency Division Multiplexing). This novel modulation scheme is implemented through the generation of chaotic sequences in a one dimensional map controlled by a parameter p which defines the central region of the map as a guard interval, the slope of the delimiting lines and the chaotic behavior of the generated sequence. This parameter also determines directly the amplitude of each symbol, making it more irregular and less predictable, avoiding the detection by eavesdroppers and increasing the security level of the link to be transmitted. Besides the change in the traditional OFDM modulator from 4QAM to chaotic one, the Fast Fourier Transform (IFFT /FFT) will be replaced by Wavelets Transform IDWT/DWT), in order to overcome some conventional OFDM s disadvantages Additionally a quadrature chaotic OFDM system was conceived, where the chaotic modulation was performed in a constellation I and Q that was submitted to the same channel conditions as the previous one. Both systems were simulated in a MATLAB® environment using the built in functions at the Communications System Toolbox and its behavior analyzed using the BER-Bit error rate versus SNR-Signal noise ratio. The obtained results were reported and scrutinized.
Sistemas de comunicações baseados em sinais caóticos representam um novo campo de estudo de transmissão em banda larga. Entretanto, sistemas baseados em sinais caóticos não apresentaram ainda um desempenho distinto em termos de taxa de erro, quando transmitidos em canais sem fios ou na presença de interferências em comparação aos sistemas tradicionais. O foco deste trabalho está na proposta de um novo esquema obtido através da conjugação das características da comunicação tradicional baseada em subportadoras ortogonais e aquelas originadas por sinais caóticos. Mais precisamente, a modulação caótica é empregada nas subportadoras de um sistema OFDM (Multiplexação por Divisão de Frequência Ortogonal) tradicional. Este novo modelo de modulação é implementado através de geração de sequências caóticas em um mapa unidimensional controlado por um parâmetro p que define uma região central do mapa como um intervalo de guarda e, por conseguinte, o comportamento caótico da sequência gerada. Este parâmetro também determina diretamente a amplitude de cada símbolo, fazendo-o mais irregular e menos previsível, evitando a detecção por pessoal não autorizado, possibilitando o aumento do nível de segurança da transmissão. Além da mudança no modulador do OFDM convencional de 4QAM para caótico, ter-se-á a substituição da Transformada Rápida de Fourier (IFFT/FFT), largamente utilizada em sistemas OFDM pela Transformada Wavelet (IDWT/DWT), de maneira a aprimorar os pontos fracos do sistema OFDM convencional. Como contribuição adicional, tem se a concepção do sinal com modulação simbólica em quadratura, ou seja, uma parte do sinal foi gerada no eixo I e a outra parte no eixo Q, criando uma modulação caótica em quadratura que é submetida aos mesmos canais da modulação caótica anterior. Os sistemas propostos foram simulados em ambiente MATLAB® utilizando-se de funções pré-existentes no modulo de ferramentas de comunicações (Communications System Toolbox) e o seu comportamento analisado em termos de gráficos que representam a relação da taxa de erro do bit (BER) versus relação sinal ruído (SNR). Os resultados obtidos foram reportados e debatidos.
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WANG, YING. "PILOT SYMBOL-BASED WAVELET COMMUNICATIONS FOR WIDEBAND FAST-FADING CHANNELS." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1148319204.
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RAWAT, URVASHI. "INFRARED AND VISIBLE IMAGE FUSION USING HYBRID LWT AND PCA METHOD." Thesis, DELHI TECHNOLOGICAL UNIVERSITY, 2021. http://dspace.dtu.ac.in:8080/jspui/handle/repository/18907.
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Image fusion is a method in which all the relevant information is collected from the input source
images and included in few/single output image. Image fusion techniques are divided into two broad
categories: spatial domain and transform domain. Principal component analysis (PCA) is a spatial
domain technique which is computationally simpler and reduces redundant information but has the
demerit of spectral degradation. Lifting wavelet transform (LWT) is a transform domain technique
which has an adaptive design and demands less memory. In this project, a novel hybrid fusion
algorithm has been introduced which combines the LWT and PCA in a parallel manner. These two
fusion methods are applied on Infrared and Visible image data set. Infrared and visible images
contain complementary information and their fusion gives us an output image which is more
informative than the individual source images. The hybrid method is also compared with
conventional fusion techniques like PCA, LWT and DWT. It has been shown that the proposed
method outperforms the conventional methods. The results are analyzed using performance
parameters standard deviation, average value, the average difference, and normalized cross-
correlation.
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Zhang, Xun. "Contribution aux architectures adaptatives : etude de l'efficacité énergétique dans le cas des applications à parallélisme de données." Thesis, Nancy 1, 2009. http://www.theses.fr/2009NAN10106/document.
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Cette thèse s'inscrit dans le cadre de la conception d'architectures reconfigurables. Plus précisément, il concerne les architectures matérielles adaptatives, ces dernières pouvant être modifiées du point de vue de leurs caractéristiques matérielles au cours de l'exécution d'une application. Nous présentons une méthodologie d'auto-configuration d'une architecture reconfigurable dynamiquement ainsi qu'une architecture permettant d'illustrer l'utilisation de la méthode. L'objectif de la méthode est de réduire la consommation d'énergie en garantissant le respect des contraintes à tout instant. La méthodologie proposée s'adresse aux architectures reconfigurables à grain épais, puisque l'unité fonctionnelle matérielle correspond à une fonction de haut niveau d'abstraction (IDWT, etc.), même si la réalisation de l'architecture est basée sur l'utilisation d'une structure reconfigurable à grain fin (FPGA). Le besoin d'adaptation choisi concerne principalement deux cas de figures. Premièrement, répondre aux variations dynamiques de la charge de calcul en cours de traitement : un accroissement ou une réduction du débit de données conduit à une inadéquation entre l'architecture et son environnement. Deuxièmement, s'adapter aux variations dynamiques de la structure de l'algorithme : dans certaines applications les traitements à effectuer changent en fonction des données qui arriventMy PhD project focuses on Dynamic Adaptive Runtime parallelism and frequency scaling techniques in coarse grain reconfigurable hardware architectures. This new architectural approach offers a set of new features to increase the flexibility and scalability for applications in an evolving environment with reasonable energy cost. In this architecture, the parallelism granularity and running frequency can be reconfigured by using partial and dynamic reconfiguration. The adaptive method and architecture have been already developed and tested on FPGA platforms. The measurements and results analysis based on DWT show that the energy efficiency is adjustable dynamically by using our approach. The main contribution to the research project involves an auto-adaptive method development; this means using partial and dynamic reconfiguration can reconfigure the parallelism granularity and running frequency of application. The adaptive method by adjusting the parallelism granularity and running frequency is tested with the same application. We are presenting results coming from implementations of Image processing key application and analyses the behavior of this architecture on these applications
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Al-hussiany, Yahya Ali Lafta. "Novel DWT-DAPSK based transceivers for DVB-T transmission and next generation mobile networks." Thesis, Liverpool John Moores University, 2012. http://researchonline.ljmu.ac.uk/6168/.
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Digital wireless communication has become one of the most exciting research topics in the electronic engineering field due to the explosive demands for high-speed wireless services, such as cellular video conferencing. The second generation Terrestrial Digital Video Broadcasting (DVB- T2) has been demonstrated to provide digital communication services with very high spectral efficiency and significantly improved performance. Orthogonal Frequency Division Multiplexing (OFDM) systems have been increasingly deployed in mobile networks for their spectral efficiency and optimum bit error rate. An OFDM system is a multi-carrier system which transmits signals from a single source at different frequencies simultaneously as parallel components. A distinguishing feature of the OFDM system is its ability to preserve high bandwidth efficiency in high speed data streams. Among the different types of OFDM systems, wavelet based systems have been demonstrated to have much better bandwidth and channel performance compared to the Discrete Fourier transform (DFT) and Discrete Cosine Transform (DCT) based systems. The DFT and DCT systems suffer from several disadvantages including less bandwidth efficiency due 'to the need for guard interval and highly complex system design. Discrete Wavelet transform (DWT) based OFDM systems naturally overcome these disadvantages by their design methodology and the technique of transmitting concentrated energy over small spectral coefficients. Several types of modulation schemes such as DPSK, QAM are employed in OFDM systems, which introduce certain penalties such as increased bandwidth and complexity of the system design. So a multilevel differential modulation technique namely Differential Amplitude and Phase Shift Keying (64 DAPSK) has been proposed as an alternative solution. DAPSK-OFDM is very suitable for high date-rate digital mobile radio channel with additive white Gaussian noise (A WGN). In this research work it has been f demonstrated that a combination of DWT -OFDM with DAPSK modulation can be employed to achieve very low peak-to-average power ratio (PAPR), improved bit error ratio (BER), and much reduced inter symbol interference (ISI) & inter-carrier interference (IeI) in wireless mobile network applications. A mathematical model has been proposed for the DWT-OFDM system with DAPSK modulation scheme in this work. The system performance has been evaluated via simulation using Matlab Simulink package and also verified using Matlab programming. This proposed DWT-OFDM with 64DAPSK hybrid system is demonstrated to have better BER (by an order of magnitude for an SNR of 25dB) performance and improved P APR (by 7.2dB) and interference values. It is also demonstrated that including companding with this system results in further reduction of PAPR. Finally, the simulation results also demonstrate that DWT-DAPSK scheme can be successfully employed in DVTB-T2 systems due to its very high spectral efficiency, much improved BER and significantly reduced PAPR performance.
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Campitelli, Marcelo Adrián. "Compressão de sinais ECG utilizando DWT com quantização não-linear e por sub-bandas." reponame:Repositório Institucional da UnB, 2015. http://dx.doi.org/10.26512/2015.12.D.19564.
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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2015.Submitted by Albânia Cézar de Melo (albania@bce.unb.br) on 2016-02-23T16:38:33Z No. of bitstreams: 1 2015_MarceloAdrianCampitelli.pdf: 2323124 bytes, checksum: 45791074bc64885c0526dc991339d062 (MD5)
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Com o desenvolvimento cada vez mais intenso da tecnologia de dispositivos biomédicos, há cada vez mais acesso aos sinais bioelétricos, o que permite grande avanço na realização de diagnósticos, planejamento de tratamentos e monitoração de pacientes. Particularmente, o eletrocardiograma (ECG) tem sido usado para muitos propósitos. Além disso, novas formas simples e de baixo custo para adquirir o ECG tem sido descobertas. Entretanto, esses avanços exigem o melhoramento dos processos de codificação do sinal de ECG, de forma a permitir seu armazenamento e transmissão eficientemente em termos de requisitos de memória e consumo de energia. Neste contexto, o presente trabalho propõe duas contribuições. Em primeiro lugar, apresenta um algoritmo de compressão de sinais ECG, utilizando transformadas wavelets, e propondo um processo de quantização novo, não encontrado na literatura. Nesse processo, a transformação é realizada utilizando a transformada discreta de wavelets (DWT) e a quantização consiste em um re-ordenamento não-linear das magnitudes dos coeficientes transformados (correção gamma) em conjunto com uma quantização por sub-bandas. A segunda contribuição consiste num estudo sistemático do desempenho das diferentes famílias de wavelets nos resultados obtidos pelo algoritmo proposto, calculando também os parâmetros ótimos de quantização para cada família wavelet utilizada. Para a análise desses métodos, foram realizados testes avaliando o desempenho do algoritmo proposto e comparando os resultados com outros métodos apresentados na literatura. Nesses testes, foram usados como referências os sinais da base de dados do Instituto de Tecnologia de Massachusetts e do Hospital Beth Israel de Boston (MIT-BIH). Uma parcela do banco de dados foi utilizada para otimizar os parâmetros de cada família wavelet no algoritmo proposto, e o desempenho final foi avaliado com todos os sinais restantes. Especificamente, para o sinal 117 do MIT-BIH, que é o sinal mais utilizado para comparar resultados na literatura, o método proposto levou a um fator de compressão (CR) de 11,40 e uma raiz da diferença média percentual (PRD) de 1,38. Demonstrou-se que o algoritmo gera melhores resultados de compressão quando comparado com a maioria dos métodos do estado-da-arte. Também se destaca a simplicidade na implementação do algoritmo em relação a outros encontrados na literatura.
With the increasing development of biomedical devices technology, there is more access to bioelectrical signals. That allows great advances in reaching diagnostics, planning treatments and monitoring patients. Particularly, the electrocardiogram (ECG) has been used for many purposes. Besides that, simple and low-cost ways to acquire the ECG have been found. Nevertheless, those advances require the improvement of the ECG signal coding processes, in a way that allows its efficient storage and transmission in terms of memory requirements and energy consumption. In this context, this dissertation proposes two contributions. Firstly, it presents an ECG signal compression algorithm, using wavelet transforms, and proposing a novel quantization process, not found in the literature. In said process, the transformation is done using the discrete wavelet transform (DWT) and the quantization consists of a non-linear re-ordering of the transformed coefficients magnitudes (gamma correction) in tandem with a sub-band quantization. The second contribution consists in a systematic study of the performance of the different wavelet families through the results obtained by the proposed algorithm, also calculating the optimum quantization parameters for each wavelet family. For the analysis of these methods, tests were done evaluating the performance of the proposed algorithm, comparing its results with other methods presented in the literature. In said tests, signals from the Massachusetts Institute of Technology and Boston’s Beth Israel Hospital database (MIT-BIH) were used as reference. A part of the database was utilized to optimize the parameters of each wavelet family, and the final performance was evaluated with the remaining signals from the database. Specifically, for signal 117 of the MIT-BIH database, which is the most used signal to compare results in the literature, the proposed method led to a compression factor (CR) of 11,40 and a percentage root-mean-square difference (PRD) of 1,38. It was demonstrated that the algorithm generates better compression results when compared to the majority of state-of-the-art methods. The simplicity of the algorithm’s implementation also stands out in relation to other algorithms found in the literature.
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Silva, Sandro Vilela da. "Projeto de uma arquitetura dedicada à compressão de imagens no padrão JPEG2000." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2005. http://hdl.handle.net/10183/7838.
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O incremento das taxas de transmissão e de armazenamento demanda o desenvolvimento de técnicas para aumentar a taxa de compressão de imagens e ao mesmo tempo mantenha a qualidade destas imagens. O padrão JPEG2000 propõe a utilização da transformada wavelet discreta e codificação aritmética para alcançar altos graus de compressão, proporcionando que a imagem resultante tenha qualidade razoável. Este padrão permite tanto compressão com perdas como compressão sem perdas, dependendo apenas do tipo de transformada wavelet utilizada. Este trabalho propõe a implementação de blocos internos em hardware para compor um compressor de imagens com perdas seguindo o padrão JPEG2000. O principal componente deste compressor de imagens é a transformada wavelet discreta irreversível em duas dimensões, que é implementada utilizando um esquema lifting a partir dos coeficientes Daubechies 9/7 descritos na literatura. Para proporcionar altas taxas de compressão para a transformada irreversível, são utilizados coeficientes reais – que são originalmente propostos em representação de ponto-flutuante. Neste trabalho, estes coeficientes foram implementados em formato de ponto-fixo arredondado, o que resulta erros que foram estimados e controlados. Neste trabalho, várias arquiteturas em hardware para a descrição da transformada wavelet discreta irreversível em duas dimensões foram implementadas para avaliar a relação entre tipo de descrição, consumo de área e atraso de propagação. A arquitetura de melhor relação custo benefício requer 2.090 células de um dispositivo FPGA, podendo operar a até 78,72 MHz, proporcionando uma taxa de processamento de 28,2 milhões de amostras por segundo. Esta arquitetura resultou em um nível de erro médio quadrático de 0,41% para cada nível de transformada. A arquitetura implementada para o bloco do codificador de entropia foi sintetizada a partir de uma descrição comportamental, gerando um hardware capaz de processar até 843 mil coeficientes de entrada por segundo. Os resultados indicam que o compressor de imagens com perdas seguindo o padrão JPEG2000, utilizando os blocos implementados nesta dissertação e operando na máxima freqüência de operação definida, pode codificar em média 1,8 milhões de coeficientes por segundo, ou seja, até 27 frames de 256x256 pixels por segundo. Esta limitação na taxa de codificação é definida pelo codificador de entropia, que possui um algoritmo mais complexo, necessitando de um trabalho complementar para melhorar sua taxa de codificação aumentando o paralelismo do hardware.The increasing demands for higher data transmission rates and higher data storage capacity call for the development of techniques to increase the compression rate of images while at the same time keeping the image quality. The JPEG2000 Standard proposes the use of the discrete wavelet transform and of arithmetic coding to reach high compression rates, providing reasonable quality to the resulting compressed image. This standard allows lossy as well as loss-less compression, dependent on the type of wavelet transform used. This work considers the implementation of the internal hardware blocks that comprise a lossy image compressor in hardware following the JPEG2000 standard. The main component of this image compressor is the two dimensional irreversible discrete wavelet transform, that is implemented using a lifting scheme with the Daubechies 9/7 coefficients presented in the literature. To provide high compression rates for the irreversible transform, these coefficients – originally proposed in their floating-point representation – are used. In this work, they are implemented as fixed-point rounded coefficients, incurring in errors that we estimate and control. In this work, various hardware architectures for the two dimensional irreversible discrete wavelet transform were implemented to evaluate the tradeoff between the type of description, area consumption and delay. The architecture for the best trade-off requires 2,090 logic cells of a FPGA device, being able to operate up to 78.72 MHz, providing a processing rate of 28.2 million of samples per second. This architecture resulted in 0.41% of mean quadratic error for each transformed octave. The architecture implemented for the block of the entropy encoder was synthesized from a behavioral description, generating the hardware able to process up to 843 thousands of input coefficients per second. The results indicate that the lossy image compressor following JPEG2000 standard, using the blocks implemented in this dissertation and operating in the maximum clock frequency can codify, in average, 1.8 million coefficients per second, or conversely, up to 27 frames of 256x256 pixels per second. The rate-limiting step in this case is the entropy encoder, which has a more complex algorithm that needs further work to be sped up with more parallel hardware.
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Rout, Satyabrata. "Orthogonal vs. Biorthogonal Wavelets for Image Compression." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/35084.
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Effective image compression requires a non-expansive discrete wavelet transform (DWT) be employed; consequently, image border extension is a critical issue. Ideally, the image border extension method should not introduce distortion under compression. It has been shown in literature that symmetric extension performs better than periodic extension. However, the non-expansive, symmetric extension using fast Fourier transform and circular convolution DWT methods require symmetric filters. This precludes orthogonal wavelets for image compression since they cannot simultaneously possess the desirable properties of orthogonality and symmetry. Thus, biorthogonal wavelets have been the de facto standard for image compression applications. The viability of symmetric extension with biorthogonal wavelets is the primary reason cited for their superior performance.
Recent matrix-based techniques for computing a non-expansive DWT have suggested the possibility of implementing symmetric extension with orthogonal wavelets. For the first time, this thesis analyzes and compares orthogonal and biorthogonal wavelets with symmetric extension.
Our results indicate a significant performance improvement for orthogonal wavelets when they employ symmetric extension. Furthermore, our analysis also identifies that linear (or near-linear) phase filters are critical to compression performance---an issue that has not been recognized to date.
We also demonstrate that biorthogonal and orthogonal wavelets generate similar compression performance when they have similar filter properties and both employ symmetric extension. The biorthogonal wavelets indicate a slight performance advantage for low frequency images; however, this advantage is significantly smaller than recently published results and is explained in terms of wavelet properties not previously considered.Master of Science
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Konczi, Róbert. "Digitální hudební efekt založený na waveletové transformaci jako plug-in modul." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-218981.
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This work deals with theory of wavelet transform and Mallat’s algorithm. It also includes the programming method of creating VST plug-in modules and describes the developement of the plug-in module, witch uses the modificated coeficients of wavelet transform to applicate the music effect.
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Maszewski, Mirosław. "Kodowanie i rozpoznawanie obrazów z wykorzystaniem zespolonych funkcji bazowych." Rozprawa doktorska, [Nakł.aut.], 2006. http://dlibra.utp.edu.pl/Content/140.
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Celem pracy było wykazanie możliwości zastosowania zespolonego dyskretnego przekształcenia falkowego do celów skutecznego kodowania i rozpoznawania obrazów w telekomunikacyjnym systemie przetwarzania obrazów
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Holdova, Kamila. "Klasifikace spánkových EEG." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-219944.
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This thesis deals with wavelet analysis of sleep electroencephalogram to sleep stages scoring. The theoretical part of the thesis deals with the theory of EEG signal creation and analysis. The polysomnography (PSG) is also described. This is the method for simultaneous measuring the different electrical signals; main of them are electroencephalogram (EEG), electromyogram (EMG) and electrooculogram (EOG). This method is used to diagnose sleep failure. Therefore sleep, sleep stages and sleep disorders are also described in the present study. In practical part, some results of application of discrete wavelet transform (DWT) for decomposing the sleep EEGs using mother wavelet Daubechies 2 „db2“ are shown and the level of the seven. The classification of the resulting data was used feedforward neural network with backpropagation errors.
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Bai, Cong. "Analyse d'images pour une recherche d'images basée contenu dans le domaine transformé." Phd thesis, INSA de Rennes, 2013. http://tel.archives-ouvertes.fr/tel-00907290.
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Cette thèse s'inscrit dans la recherche d'images basée sur leur contenu. La recherche opère sur des images eprésentéesdans un domaine transformé et où sont construits directement les vecteurs de caractéristiques ou indices. Deux types detransformations sont explorés : la transformée en cosinus discrète ou Discrete Cosine Transform (DCT) et la transforméen ondelettes discrète ou Discrete Wavelet Transform (DWT), utilisés dans les normes de compression JPEG et JPEG2000. Basés sur les propriétés des coefficients de la transformation, différents vecteurs de caractéristiquessont proposés. Ces vecteurs sont mis en oeuvre dans la reconnaissance de visages et de textures couleur.Dans le domaine DCT, sont proposés quatre types de vecteurs de caractéristiques dénommés "patterns" : Zigzag-Pattern,Sum-Pattern, Texture-Pattern et Color-Pattern. Le premier type est l'amélioration d'une approche existante. Les trois derniers intègrent la capacité de compactage des coefficients DCT, sachant que certains coefficients représentent une information de directionnalité. L'histogramme de ces vecteurs est retenu comme descripteur de l'image. Pour une réduction de la dimension du descripteur lors de la construction de l'histogramme il est défini, soit une adjacence sur des patterns proches puis leur fusion, soit une sélection des patterns les plus fréquents. Ces approches sont évaluées sur des bases de données d'images de visages ou de textures couramment utilisées. Dans le domaine DWT, deux types d'approches sont proposés. Dans le premier, un vecteur-couleur et un vecteur-texture multirésolution sont élaborés. Cette approche se classe dans le cadre d'une caractérisation séparée de la couleur et de la texture. La seconde approche se situe dans le contexte d'une caractérisation conjointe de la couleur et de la texture. Comme précédemment, l'histogramme des vecteurs est choisi comme descripteur en utilisant l'algorithme K-means pour construire l'histogramme à partir de deux méthodes. La première est le procédé classique de regroupement des vecteurs par partition. La seconde est un histogramme basé sur une représentation parcimonieuse dans laquelle la valeur des bins représente le poids total des vecteurs de base de la représentation.
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Novotný, Radek. "Aplikace waveletové transformace v software Mathematica a Sage." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220339.
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This thesis focuses on image processing using wavelet transform. The usage of wavelet transform is analysed especially for image compression and image noise reduction purposes. The analysis describes in detail aspects and application of the following wavelet transform methods: CWT, DWT, DTWT, 2D DWT. The thesis further explains the meaning of the mother wavelet and studies certain specific kinds of wavelets, kinds of thresholding and its purposes and also touches on the JPEG2000 standard. Mathematica and Sage software packages were used to design algorithms for image compression and image noise reduction, utilising relevant wavelet transform findings. The concluding part of the thesis compares the two software packages and results obtained using different algorithms.
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Zhu, Dongqing. "Time-frequency and Hidden Markov Model Methods for Epileptic Seizure Detection." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1242070584.
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Mikulčík, Ondřej. "Pokročilé metody pro zabezpečení multimediálních dat." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220611.
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To protect the the copyright of multimedia works have been developed watermarking techniques, that insert an invisible watermark to the original data. The aim of this thesis was to explore modern watermarking techniques, choose three of them and realize them. Also test them, evaluate their properties and possibly improve them. All methods insert a watermark into luminance component of the original image, and work with binary or black and white watermark. All techniques work in the frequency domain using discrete wavelet transform. For the implementation of methods, have been developed software named "Watermarking" that has been programmed in JAVA Version 7. The first chapter describes the types of watermarks, the general process of insertion and extraction, watermarking systems and important feature requests of embedded water- marks. In addition, qualitative methods are mentioned for their comparisons and testing. The chapter also contains a theoretical description of the used transformations and functions. In the second chapter is described the user interface of the software "Water- marking". Chapters three and four contain a theoretical description of the implemented methods and description of implementation of insertion and extraction processes of the watermark. Also there are discussed the exact procedures for testing, the sample data, and the results which are clearly displayed in the tables. The fifth chapter discusses in detail the results obtained in testing the robustness of the watermark, using the software StirMark. In the conclusion are evaluated the advantages and disadvantages of methods and quality parameters.
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陳毓宏. "Reconfigurable IP of DCT and DWT for image transform coding." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/06295153574776263281.
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碩士國立交通大學
電機學院IC設計產業專班
97
This paper presents a design and development of a reconfigurable architecture for image transform coding. Because of DCT (Discrete Cosine Transform) is usually used in JPEG, MPEG, and H.26X system. And DWT (Discrete Wavelet Transform) is used in JPEG2000 system. They are both the part that damage huge computations in system. So we want to integrate DCT and DWT architectures with the same hardware to reduce hardware requirement for these system. To merge DWT into DCT, we use butterfly structure for DCT and 9/7 convolution based structure for DWT that not only can make DCT computations time faster, but also can increase hardware utility rate for DWT. To reduce hardware area and speed up DCT function, we use the subexpression to reduce our hardware requirement and canonic signed digit (CSD) encoded multiplier to design ours multiplication that can effective reduce multiplication area, and also can speed up the chip to achieve the mpeg spec. The architecture executes a DCT and DWT achieving up to 90% higher throughput and occupying as little as 20% area compared to a commercial digital signal processing and other application- specified integrated circuit implementations while maintaining precision. A comprehensive comparative analysis is also provided. The proposed architecture is implemented in 0.13- m CMOS technology and operates with a 100-MHz clock.
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Hsu, Yi-min, and 許逸民. "Image Tamper Detection and Recovery based on DWT and DCT." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/60903685477926912861.
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碩士立德大學
應用資訊研究所
95
In this paper, a reversible data embedding for tamper-proof watermarks technique is proposed. In generally, watermarking is used for the purpose of ownership protection. The important regions in the image can be selected by the users as the region of interest (ROI) to protect. And those ROIs are regarded as the watermark and then being embedded in the image. When these important regions are tampered or faked by malicious attacker, the system can detect and recover the ROI. The system extracts the characteristic values by Discrete Cosine Transform (DCT) and embeds those characteristic values into the image by Discrete Wavelet Transform (DWT) to hide those watermarks. The difference between the embedded and original images is invisible by the human eyes. If the image is tampered, the system can detect the tamper and recover the original ROIs. The proposed method is simple but efficient; in addition, the recovered quality of protected ROI is very well from the simulation tests.
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Hsu, Heng-chia, and 許恆嘉. "PCB Edge Detection with DWT." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/16419932987493613598.
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碩士國立交通大學
電機與控制工程系
89
To develop an appropriate algorithm for PCB (Printed Circuit Board) image edge detection is the main subject of this thesis. The algorithm proposed in this thesis can be applied only on digital gray-level images of PCBs. Instead of the conventional idea of difference, DWT (Discrete Wavelet Transform), an alternative and novel method for basis change despite Fourier Transform, is employed. In this thesis, digital gray-level images of PCB are considered as vectors existing in the vector space constructed by selected basis that are the dilations and translations of Harr function and box function. By using DWT, image-edge-related information in digital gray-level images can be extracted easily. Not only DWT but also optimization algorithms are involved. Two well-known optimization algorithms, gradient method and one-dimensional Newton's method, are adopted for tuning the result into the best condition. The purpose of adopting two-stage optimization algorithm, gradient method and one-dimensional Newton's method, is to diminish the elapsing time in etermining the weighting vectors by searching the maximum step-size in the determined descent direction. Step-size and descent direction are determined by one-dimensional Newton's method and gradient method, respectively. When the weighting vectors are obtained, the two-stage optimization can be abandoned. Only are the weighting vectors and DWT used for PCB image edge detection in the rest of PCBs.
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Sahu, Saurabh. "Efficient Image Fusion Using DWT." Thesis, 2015. http://ethesis.nitrkl.ac.in/7309/1/2015_Efficient_Sahu.pdf.
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The method of combining important details from two or more source images into a final fused image is known as Image Fusion. When compared to any of the other input images, our fused output image will have more detailed information in it. The objective of image fusion is to obtain the most desirable data from each image. Multi sensor image fusion algorithm based on three different fusion techniques have been discussed in this paper. Those are “Pixel Level Iteration”, “Directional Discrete Cosine Transform (DDCT)”, and “Discrete Wavelet Transform (DWT)”. The outcomes are additionally outfitted in picture and table organization for near examination of above methods. This paper shows the three distinctive picture combination strategies and there relative results, as the routine combination methods Direct Pixel Iteration and Discrete Cosine Transform has a few downsides. The similar study presumes that Discrete Wavelet Transform is one of the best and most effective algorithm for Image Fusion. In this thesis, Discrete Wavelet Transform based two calculations are proposed, these are Maximum Intensity Replacement and Band Averaging Method.
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Yi-Chia, Chuang, and 莊益嘉. "VLSI Architecture Design of DCT-based to DWT-based Image Transcoder." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/70130900366990960482.
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碩士國立清華大學
電機工程學系
90
The wavelet-transform based image compression technique has been widely used in the newest image compression standards, such as JPEG200 and MPEG4. In spite of high compression rate and flexibility in the ultilization of wavelet-transform, older image compression technique, DCT-transform is still used in the older image compression standards, such as MPEG1, MPEG2 and H.263. Because of the coexistence of DCT-transform and DWT-transform, we try to design a DCT to DWT transcoder. If we have this kind of transcoder, the incompatibility between older image compression standards and newer one will be resolved. It’s well known that DCT-transform and DWT-transform are composed of their own mathematical equations. Many Fast DCT-transform and Fast DWT-transform algorithms have been developed by factorizing these equations. Beside factorization, some properties, like symmetry and particular coefficients can be used to speed up the hardware computation speed and reduce chip area. In our current research, we use matrix operation to investigate if there exists some ways to meet the requirements. This kind of investigation is similar to mathematical equation factorization. Accordingly, we have developed different kinds of hardware architectures of the DCT to DWT trascoder. In this thesis, we summarized our matrix operation investigation. Some architectures have less area but lower computation speed and others have higher computation speed but must sacrifice its own area. By the TSMC .35um cell-library, each of the proposed transcoder in this research achieves 50-MHz working speed. Comparisons between each of them are shown later.
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Lo, Pi-Te, and 羅彼得. "A New Robust Image Watermarking Technique Based on DWT and DFT." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/fnbpk5.
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Ku, Ching-Shiuan, and 辜慶軒. "The Digital Watermarking Embedding Technology Based on DWT-SVD-DCT Transformation." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/21811625457269424478.
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碩士國立宜蘭大學
電子工程學系碩士班
102
In the information age, a large amount of digital image information can be acquired from the Internet. However, any unauthorized tampering may seriously jeopardize the legitimate interests of the digital information owner, and the protection of intellectual property rights has become an important issue. Hence, image watermarking is used to resolve the intellectual property contentious issues. For many transform-domain watermarking techniques, attempts have been made to exploit various transformations to extract image features, and then embed the watermark into those feature parameters. This study used an innovative digital watermarking technology constructed by integrating the discrete wavelet transform (DWT), singular value decomposition (SVD) and discrete cosine transform (DCT). The transformation technologies of DWT, SVD, and DCT have their respective advantages. DWT can resolve the low frequency image, SVD can capture the geometric textures of various layers, and DCT can be used to analyze the components of specific frequencies. This study first identified the feature parameters of the composite DWT-SVD-DCT domain, and then used the quantization index modulation (QIM) rule to embed the watermark. To verify the effect of the proposed scheme, the resulting performance were compared with five other watermarking technologies. The performances of the watermarking technologies will evaluated by embedding a 64x64 binary watermark into five 512x512 greyscale images. The results showed that the proposed scheme can result in a PSNR value up to 42 dB after watermark embedding. For a watermarked image with a PSNR greater than 40dB, the differences between the watermarked and original image are almost undetectable by human eyes. The proposed scheme also exhibited satisfactory robustness against common digital signal processing attacks. Even under the high-intensity attack of JPEG compression (e.g., quality factor = 20), the average mean of the normalized correlation (NC) values of the recovered watermarks still reached 0.889. Moreover, the proposed method can effectively resist the general attacks by Gaussian noise, salt and pepper noise, filtering, rotation, cropping, and brightness adjustment.
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Lin, Hung-ju, and 林宏儒. "A Study of DWT-Based Steganography." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/626fm8.
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碩士朝陽科技大學
網路與通訊研究所
93
Abstract In this thesis, we proposed a novel stegangraphy method utilizing the features obtained from Discrete Wavelet Transform (DWT). Applying a secure coding scheme, the secret messages are embedded into the three high frequency sub-bands of DWT coefficients. Since the portion which human eyes are sensitive to, the low frequency sub-band, remains unaltered, the image quality after secret messages embedding is increased. According to different needs of embedding capacity, we explain the embedding method in five cases. In addition to high embedding capacity and image quality, the proposed approach provides respectable security as well. Because the original secret messages are arithmetically manipulated before embedding, they would not be recovered directly from the rightmost Least Significant Bits (LSBs) of coefficients in any sub-band.
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Tsai, Cheng-Fu, and 蔡正富. "A DWT-Based Digital Audio Watermarking." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/72166077143270442932.
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碩士國立東華大學
資訊工程學系
92
In audio signals, with the widespread use of Internet and proliferation of digital audio distribution in MP3 form make the copyright protection of digital audio works more and more important. In this thesis, a DWT-based digital audio watermarking is proposed. With the Discrete Wavelet Transform（DWT）, the audio signal can be transformed into frequency domain ranging from low frequency to high frequency. Besides, the high frequency spectrum is less sensitive to human ear. That is the reason why the high frequency component is usually discarded in the compression process. Therefore, information to be hidden can be embedded into the low frequency component to against the compression attack. In our experiments, the logo of National Dong Hwa University (NDHU) is embedded into an audio signal. The performance of the proposed technique is evaluated by the normalized correlation between the original logo and the extracted one. Experiment results show that the proposed algorithm is robust to the compression and noise attacks.
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Anoh, Kelvin O. O., Raed A. Abd-Alhameed, Steven M. R. Jones, Yousef A. S. Dama, and Mohammed S. Bin-Melha. "On the wavelet families for OFDM system comparisons over AWGN and Rayleigh Channels." 2013. http://hdl.handle.net/10454/9609.
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NoIn the study of OFDM systems, discrete wavelet transforms have been reported to perform better than Fast Fourier Transform in multicarrier systems (MCS) - in terms of spectral efficiency because they can operate without a cyclic prefix, have reduced side-lobes and improved BER. However all of the wavelet families do not perform alike. This study has investigated various wavelet families such as Daubechies, Symlet, Haar (or db1), biorthogonal, reverse-biorthogonal and Coiflets for OFDM system design over an AWGN and multipath channels. Results show that Daubechies, Symlet, Haar and Coiflet wavelet families perform considerably better than other families considered, thus these families could be better in OFDM.
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Kuo, Ping-nan, and 郭炳南. "Watermarking Scheme based on Majority Voting，DWT-DCT Composite and Error Correction Techniques." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/66004911284990449929.
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碩士國立中興大學
電機工程學系所
97
Abstract— In this thesis we present a digital watermarking scheme that is based on DWT-DCT composite, error correction code and majority judgement techniques. For the purpose of increasing the robustness of watermarking against attacks from image transmission, we encode an image and embedded watermarks by Turbo code with error correction capability. Three identity encoded watermarks was embedded into the host image, two watermarks were using a combine method of the Discrete Wavelet Transform (DWT) and the Discrete Cosine Transform (DCT) algorithm and the other one is embedded into the three lowest detail suband images by a significant triplet of wavelet coefficients. The performance of the proposed scheme is tested on a series of attacks in geometry processing, image processing and compression. Examples are down-scaling, Gaussian filtering, uniform noise addition, JPEG2000, etc. The corresponding experimental results show that the proposed watermarking scheme has better performance.
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Lan, Ming-Fu, and 藍明富. "Architecture Design and VLSI Implementation of DCT-based to DWT-based Image Transcoder." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/91926960016897932715.
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碩士國立清華大學
電機工程學系
89
Abstract The wavelet-transform based applications and their architecture design have been widely discussed in literature, and already proposed for image compression standard of modern era. The main advantage of using DWT is to cope with high compression demand and still get good image quality. Another advantage is its high scalability. According to these features, DWT- based images are extremely suitable for transmission over the Internet. Nevertheless, most of the image data are DCT-based. For this reason, we propose a DCT-based to DWT-based image transcoder to convert the pre-existent image data. We utilize the matrix operation of given transform matrices to get the new transform matrix and study the transcoding procedures. Accordingly, their architectures are proposed. We design the proposed transcoder based on the principle of pipelining. The proposed architecture can offer two formats of DWT to support the new image standards, such as JPEG2000 and MPEG4. One works on the whole image, and the other on a tile. It can be chosen by user to support different coding ways. According to TSMC 0.35um Cell-library, our design of the mentioned transcoder can achieve 50-MHz working speed with 22305 gate-counts, consuming 62mW of power.
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Hsu, Wen-long, and 徐文龍. "An IP Design of DWT with BIST." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/01478840155438936594.
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碩士中華大學
資訊工程學系碩士班
88
Recently, Discrete Wavelet Transform (DWT) has been widely used in many applications. These applications include signal processing, image processing, numerical, statistical, and medical analysis. Compared with other transforms, such as Fourier transform and discrete cosine transform (DCT), DWT has the following advantages: 1. Can provide appropriate time-frequency window, 2. Can reduce the distortion of signal analysis, 3. The complexity of computation is O(N), and 4. Can be easily implemented by VLSI design. Based on these advantages, DWT becomes very convenient for analyzing and computing the data. Due to the increasing complexity of VLSI design, reusable silicon intellectual properties, IP, becomes one of the possible solutions for the IC industry. In this thesis, an 1D-DWT architecture has been proposed. The following important factors have been considered and implemented in the proposed design such that it can be an IP easily: 1.High-Speed: we have developed an efficient DWT algorithm such that the operational speed is satisfactory. Furthermore, the area of the proposed is minimal compared with other designs.. 2.Reconfiguration: there are two ways to reconfigure the proposed design. Firstly, the data sizes of internal processing elements can be reconfigured to increase the precision, and secondly, the number of processing elements can be also changed to improve the accuracy of the data. 3.Testing: the proposed architecture is very regular, hence it is very suitable for BIST design. We have modified our design with BIST capability, such that the testing of proposed architecture becomes very simple. The proposed architecture has been implemented by using FPGA and ASIC. Experimental results show that our area is superior to other existing DWT designs. The operational speed can be 30MHz for FPGA implementation, and 100MHz for the ASIC implementation. Hence, the design can be used for the real-time compression applications. Since BIST is integrated in the proposed design, the fault coverage can be as high as 98.7%.
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Ting-Hsun, Wei, and 魏廷勳. "Generic DWT Processors using Limited Resource Scheduling." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/94506417940935624496.
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碩士國立交通大學
電機與控制工程系
89
Wavelet transformations have become interesting to the signal processing society in the last decade. The Discrete Wavelet Transformation (DWT) has been employed in DSP applications such as signal analysis, image processing, numerical analysis, fractal analysis, and so on. Research of DWT implementation has focused on decreasing the storage size and increasing hardware utilization; however, very few papers deal with the limited-resource implementation. The limited-resource implementation is one of the most important issues in System-On-Chip (SOC) design. This thesis proposes a scheduling algorithm for limited-resource DWT implementation. The proposed scheduling algorithm can flexibly perform different DWT operations in terms of the length of FIR filters, the size of data blocks, and the dimension of wavelet transform. Using the scheduling algorithm the DWT implementation features high degree of flexibility, scalability, and hardware utilization. Finally, we propose an Intellectual Property (IP) generator to develop DWT chip based on a set of architectural parameters. To demonstrate the proposed DWT processor design we implement a Db(9,7) DWT IC using 4 MACs in TSMC 0.35 1P4M CMOS technology. As a result, the chip size is 3294.2 3288.6 , including standard cell area ( ), and two 2048 x 16 bits asynchronous sram macro area ( ). It can operate in 50 MHz, and perform 46 frames/sec with 512x512 pixel in 2-D DWT operation.
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WANG, SHIH-WEN, and 王世文. "CDMA-based Watermarking Schemes in DWT Domain." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/18608246868379486169.
Full textAbstract:
博士國立暨南國際大學
資訊工程學系
104
In recent years, Smart mobile devices have become widely used because of their low cost and user –friendly. Thus it makes the protection of digital data copyrights be taken seriously. The digital watermarking technology means that hiding the secret message (watermark) into the carrier (image or video) that the naked eye of the people cannot perceive any abnormality, and thus to achieve the protection of copyrights. This dissertation first exploits a method which spreads the watermark by the CDMA technology and hides the spread data in the DWT domain. Next, a variance-reduction technique is proposed to enhance the robustness of watermarking.
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Patel, Kiran. "Hardware Architecture for Image Denoising Using DWT." Thesis, 2016. http://ethesis.nitrkl.ac.in/9299/1/2016_MT_KPatel.pdf.
Full textAbstract:
The use of multiresolution technique for time-frequency analysis of signal with high directionality has found its widespread acceptance in many digital image processing applications. The demand of high speed processing and time critical tasks required a time efficient hardware implementation of such techniques. In this thesis we design and implement a flexible hardware architecture for the 2D Discrete Wavelet Transform (DWT). This architecture can be configured to perform both the forward and inverse DWT for any DWT family, using fixed-point arithmetic and without auxiliary memory. The implementation of DWT can be done using convolution and Filter Bank (FB) based approach, but we adopt Lifting scheme architecture because of its effi- cient time complexity.
The design of the architecture is done in VHDL which provides concurrent execution of statements. Initially, the DWT core is modeled using MATLAB and parameterized in VHDL. The VHDL model is then simulated using ModelSim PE Student Edition 10.4a for the implementation of Cohen-DaubechiesFeauveau CDF 5/3 versions of the DWT. We have compared its efficacy with MATLAB based implemented method. Its potential is also demonstrated to perform image denoising task under additive white Gaussian noise (AWGN). The results indicate that both the implementation of CDF 5/3 hardware and denoising produce satisfactory results but with lower time complexity. The comparison of results is demonstrated using performance measure indices.
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Jassim, Taha D., Hussain Al-Ahmad, Raed A. Abd-Alhameed, and Ahmed M. N. Al-Gindy. "Two levels block based wavelet watermarking algorithm for still colour images." 2014. http://hdl.handle.net/10454/10656.
Full textAbstract:
NoA robust watermarking technique is implemented for copyright protection. The proposed method is based on 2-level discrete wavelet transform (DWT). The embedded watermarking information is a mobile phone number including the international code. The first level of the DWT transformation is applied on 16×16 blocks of the host image. All the coefficients of the 8×8 low-low (LL1) first level sub-band are grouped into one matrix. The second level of the DWT is then applied to the grouped matrix from the first level transformation. The highest coefficient from the LL2 sub-band (4×4) is used for embedding the watermark information. The extracting process is blind since it does not require the original image at the receiver side. The distortion in the host image due to the watermarking process is minimal and the PSNR is greater than 60 dB. The proposed algorithm showed robustness against several attacks such as scaling, filtering, cropping, additive noise and JPEG compression.
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Lin, YihFeng, and 林義峰. "A Robust DWT-based Watermarking for Still Images." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/60067665811326118484.
Full textAbstract:
碩士國立東華大學
資訊工程學系
89
This thesis presents a simple and effective DWT-based frequency-domain image watermarking technique. The watermark information is inserted into all significant coefficients of wavelet quadtrees. To provide the maximum strength transparent watermark, the characteristics of the human visual system (HVS) on frequency-domain have been incorporated into the watermark insertion design. For robustness, we proposed three ideas: (1) Significant coefficients of wavelet quadtree, (2) Adaptive threshold, α, and (3) The weight, γ , imposed on the JND value of each subband. The watermark used is a visually recognizable binary image rather than a randomly generated sequence of bits. Thus, human eyes can easily identify the extracted watermark. Before embedding, the pseudo-random permutation technique is used to prevent the watermark from tampering or unauthorized access by attackers. Experimental results show that the proposed method is resistant to some image-processing operations and JPEG compression with high compression ratio. Moreover, the algorithm for watermark extraction is simple and fast.
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Luo, Min-Yao, and 羅銘耀. "A DWT-based Watermarking Scheme for Color Images." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/25403665581792550221.
Full textAbstract:
碩士國立東華大學
資訊工程學系
92
A robust DWT-based watermarking for color image scheme is proposed in this thesis. Most watermarking researches emphasized on gray image in recent years. To welcome the era of multimedia, we must develop the digital watermarking technique for color image. Because color image includes the information of three R G B color channels, and correlation exists among RGB color channels, the watermark should not be directly embedded into any RGB channel. The RGB color spaces are first converted into YCbCr color spaces. Followed by this transformation, the watermarking technique for gray image can be exploited. At first, the images of luminance and chroma are converted into DWT frequency domain. We then sub-sample the binary watermark and embed watermark with different resolution into the corresponding LSBs of the different bands. In the process of watermark extracting, the different size of watermark is reconstructed by statistically counting the LSBs of each frequency band in YCbCr domains. Finally, the original size of watermark image is recovered by appropriate reconstruction. Experimental results show that the proposed method can resist many different attacks. It is a watermarking technique with robustness and blindness.
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Huang, Pei-Ming, and 黃培銘. "Image Sharing Watermarking Scheme Base on DWT-SVD." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/76876128750231482700.
Full textAbstract:
碩士國立宜蘭大學
資訊工程研究所碩士班
96
In this paper, one kind of new watermarking technology was proposed .It will improve robustness of the watermark. We use non-extend visual cryptography to produce two share images. Simultaneously it may also solve the existing conditions : public verification and watermark security. In the first share image , we use the DWT and SVD transformation. And we can not only get the more robust and stabile watermark to resist all kinds of the attacks, but also we don’t need original image to extract watermark, so it can enhance quality and won’t waste storage. Finally, we can use same technology to recover extract’s watermark . The other share image used by the idea of blakley secret sharing, just regards image as the main key. When reconstructing the original image, we just need to gather two shared images and calculate every two pixels from these .
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lan, Sheng-yu, and 藍勝宇. "A DWT based Robust Watermarking for Copyright Protection." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/zjd655.
Full textAbstract:
碩士國立臺北科技大學
電腦與通訊研究所
96
Because of the arrival of digital world, media in digital form can be easily altered, duplicated and spread which causes the rights and interests of original author and copyright owner are compromised or destroyed. Therefore, the protection of the intellectual property rights of digital information has come to attention. Digital watermark provides a simple and effective way of protection for property of the kind. Nowadays, more and more studies have been thrown to the field of digital watermark. In this thesis, a method of robustness and blind extraction watermark has been put forward. The main purpose of this method is to protect the intellectual property right of static images. The basic concept is to utilize wavelet transformation where, according to different characteristic coefficient on different band, three methods will be applied respectively as following. 1. Lattice code based on communication principle 2. Insignificant coefficient based on JND of human visual model 3. Quantization Index Modulation based on SVD The three methods above will achieve the goal of embedding watermark on the premise of keeping image fidelity. The experimental results prove that the proposed method presented in this thesis will have immunity to the attacks of various image compression, commonly used image processing methods and geometric methods. Additionally, because this approach is blind watermark, which means neither original image and nor its related information is needed, it is a very convenient and practical method of watermark.
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李俐玲. "A Key-based image Watermarking system using subblock composition in DCT domain and DWT domain." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/12592683760167293037.
Full textAbstract:
碩士國立中央大學
電機工程研究所
89
In this thesis, we propose a novel watermarking system that is highly robust against attacks without perceptible image degradation. In addition, the original image is not needed in watermark extraction. It operates either in the DWT domain or the DCT domain. This system integrates three important ideas to provide extellent watermarking performance. The first idea is to use a secret key that is generated based on the watermark logo and the host image. Based on the polarity of the transform coefficients and the key, the original watermark can accurately be extracted. The second idea is to use subblock composition to filter out frequency transform blocks that are not suitable for watermark embedding. A Tri-state Exclusive-Or (TXOR) operator is then applied in qualified subblock to embed the watermark. This technique further improves the robustness. The third idea is the deadzone shifting with human visual system. For watermark embedded transform blocks, if the coefficients are near the threshold, they will be shifted toward two ends so that the embedded watermark is not noticeable but more robust. With the integration of the above three state-of-art techniques, the resulting watermarking system has excellent performance. Simulation results confirm that the proposed system is extremely robust against cropping, JPEG, JPEG2000, and SPIHT compression.
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Asif, Rameez, Abubakar S. Hussaini, Raed A. Abd-Alhameed, Steven M. R. Jones, James M. Noras, Elmahdi A. Elkhazmi, and Jonathan Rodriguez. "Performance of different wavelet families using DWT and DWPT-channel equalization using ZF and MMSE." 2013. http://hdl.handle.net/10454/9618.
Full textAbstract:
NoWe have studied the performance of multidimensional signaling techniques using wavelets based modulation within an orthogonally multiplexed communication system. The discrete wavelets transform and wavelet packet modulation techniques have been studied using Daubechies 2 and 8, Biothogonal1.5 and 3.1 and reverse Biorthognal 1.5 and 3.1 wavelets in the presence of Rayleigh multipath fading channels with AWGN. Results showed that DWT based systems outperform WPM systems both in terms of BER vs. SNR performance as well as processing. The performances of two different equalizations techniques, namely zero forcing (ZF) and minimum mean square error (MMSE), were also compared using DWT. When the channel is modeled using Rayleigh multipath fading, AWGN and ISI both techniques yield similar performance.
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Yang, Xin-Lun, and 楊鑫崙. "A DWT-based Watermarking Scheme with Multi-bands’ Detection." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/52942391123810393620.
Full textAbstract:
碩士國立東華大學
資訊工程學系
90
Abstract A feasible DWT-based watermarking scheme is proposed in this thesis. The scheme is designed based on the idea of extracting watermark from those stable trends of DWT subbands’ distribution. The watermark is embedded by modifying all coeffi-cients of each subband according to their modifiable capacity. The modification of coefficients is based on aspect of implementation and observation on DWT in digital image. It is also mentioned that how different attacks influence the ability of watermark scheme under similar structure and how the watermark extracted from those undam-aged subbands. In addition, even using the same embedding process, different ex-tracting steps would make different results. Experimental results demonstrate that the idea is accurate. The proposed method is robust enough to tolerate most of image-processing operations. Besides, the obser-vation and analysis of DWT coefficients and attack behaviors are import reference to relate research work.
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李國彰. "Parity-check fragile watermarking and DWT-based robust watermarking." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/78427328796652637958.
Full textAbstract:
碩士國立臺灣師範大學
機電科技研究所
92
In this research, we focus on the issues of the digital image authentication and ownership verification. We proposed a fragile watermarking and two robust watermarking algorithms to solve these problems respectively: A parity-check fragile watermarking technique for color image authentication is proposed. First, we generate a series of random numbers with the number equal to the number of pixels in the image. The random numbers are used to select predefined patterns for parity checking. The LSB of each pixel is encoded according to the result of parity check. To avoid some special cases of gray level, the pixel is encoded further by a simple XOR operation with the same random number. The proposed scheme is simple, secure, and public. In addition, the tamper detection is pixel based. Experimental results show that the proposed technique can accurately indicate the altered areas under many attacks of image processing. Two robust watermarking algorithms based on the property of the multiresolution signal decomposition of the discrete wavelet transform are proposed. In the first algorithm, we embed the encrypted watermarks into the wavelet coefficients of the intermediate frequencies separately correspond to blue, green, and red image planes. The watermarks are embedded repeatedly in different relative locations. After that, extraction of the watermark is based on the voting scheme. In the second algorithm, we embed the encrypted watermark into the wavelet coefficients of the two similar intermediate bands. The embedding procedure is based on the magnitude relation between the related coefficients. By the experimental results, both the proposed watermarks could survive under certain attacks to show the robustness of the watermark and to serve as a basic copyright protection scheme for digital images.