Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 45 for “"Wavelet transforms"”.
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Wavelet Transforms for Stereo Imaging
… especially when a new mathematical tool such as wavelet analysis becomes mature.<br/><br/>The aim of the thesis is to investigate the stereo matching approach using wavelet transform with a view to producing efficient and dense disparity map outputs. After the shift invariance property of various …
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Detecting anomalies in remotely sensed hyperspectral signatures via wavelet transforms
… from -95dB to -50dB. The system utilizes a wavelet-based method (discrete wavelet transform) to extract an energy feature vector from each input pixel signature. The dimensionality of the feature vector is reduced to a one-dimensional feature scalar through the process of linear discriminant …
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Applications of wavelet transforms in pattern recognition and de-noising
In this thesis, we study the application of wavelet transforms in two important areas: pattern recognition and de-noising. In the area of pattern recognition, we propose and implement two invariant descriptors for the recognition of 2-D patterns. The first invariant descriptor is concerned with …
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Orthogonal Filters and the Implications of Wrapping on Discrete Wavelet Transforms
Discrete wavelet transforms have many applications, including those in image compression and edge detection. Transforms constructed using orthogonal filters are extremely useful in that they can easily be inverted as well as coded. We review the major properties of three well-known orthogonal …
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Multi-dimensional continuous wavelet transforms and generalized fourier transforms in Clifford analysis
… three mathematical analysis domains: Continuous Wavelet Transform, Fourier Transform and Clifford Analysis, and consists of three parts in which these domains interact. The one-dimensional continuous wavelet transform (CWT) is a successful tool for signal and image analysis, with applications in …
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Analyzing the Effect of Moving Resonance on Seismic Response of Structures using Wavelet Transforms
… due to 22 far field ground motion records. The wavelet coefficient plots gave very good detail of the characteristics of the ground motions that were not clear from the acceleration time histories and response spectra plots. Instances of moving resonance were found out to be significant. …
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Wavelet transform methods for identifying onset of SEMG activity
… (sEMG) activity. Applying methods from wavelet theory developed in the past decade to digitized signals, a robust algorithm has been designed for use with sEMG collected during reaching tasks executed with the less-affected arm of stroke patients. The method applied both Discretized …
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The Statistical Theory of Stationary Turbulence
… the theory of turbulence as well as that of wavelet transforms. The main contribution to the theory of turbulence is an extension of the von Karman-Howarth equation to turbulence that may be either two- or three-dimensional, and for which external forcing maintains the state of statistical …
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Assessing self-similarity in redundant complex and quaternion wavelet domains: Theory and applications
… due to irregularities in the signals or images. Wavelet-based spectral tools have become standard solutions for such problems in signal and image processing and achieved outstanding performances in real applications. This thesis proposes three novel wavelet-based spectral tools to improve the …
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Filter-bank transforms with exact inverses
Uniformly sampled filter-bank transforms and their inverses are introduced and the conditions to obtain perfect reconstruction upon inversion are explored. It is shown that perfect reconstruction requires both filter addition and multiplication and the necessary and sufficient conditions for these …
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Applications of Multiwavelets to Image Compression
… of much study over the past decade. Advances in wavelet transforms and quantization methods have produced algorithms capable of surpassing the existing image compression standards like the Joint Photographic Experts Group (JPEG) algorithm. For best performance in image compression, wavelet …
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Wavelets Based on Second Order Linear Time Invariant Systems, Theory and Applications
This study introduces new families of wavelets. The first is directly derived from the response of Second Order Underdamped Linear-Time-Invariant (SOULTI) systems, while the second is a generalization of the first to the complex domain and is similar to the Laplace transform kernel function. The …
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Image Compression by Wavelet Transform.
… <p>This thesis studies image compression with wavelet transforms. As a necessary background, the basic concepts of graphical image storage and currently used compression algorithms are discussed. The mathematical properties of several types of wavelets, including Haar, Daubechies, and …
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Hypercomplex scaling and wavelet filters: their discovery and their application to colour vector image processing
… existing work and find new discrete scaling and wavelet filters with quaternion coefficients and the first with Clifford Cl(1,1) and Cl(2,0) coefficients; and then to demonstrate the use of these filters by finding hypercomplex wavelet transforms of colour vector images. We solve certain symbolic …
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Analysis and techniques for non-intrusive appliance load monitoring.
… sensing. Time-frequency analysis methods such as Wavelet transforms are carefully examined and machine learning classifiers are used to develop the appropriate prediction models. The results have shown that the use of different Wavelet functions can significantly affect the classification …
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Analysis of time-varying harmonics in electrical distribution systems
… voltages is presented. In the second method, wavelet transforms is applied to harmonic signal variations. The Discrete Wavelet Transform is used to quantify harmonic changes with time. Experimental data of fundamental and harmonic currents are analyzed both methods and the results presented. …
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Structural Damage Assessment Using Artificial Neural Networks and Artificial Immune Systems
… the acceleration data with the use of discrete wavelet transforms (DWT)s first. The DWT coefficients are used to calculate energy ratios, which are then classified using a neural network and an AIS algorithm known as negative selection (NS). The effectiveness of both methods are validated using …
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Automated mammographic mass shape classification using wavelets and neural networks
… of the thesis is to demonstrate the utility of wavelet transforms with artificial neural networks for the classification of mammographic mass shapes. A fully automated mammographic classification system has been developed to distinctly classify mass shapes as either round, which typically …
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