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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 35 for “"Discrete Wavelet Transform (DWT)"”.
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Hybrid DWT-DCT algorithm for image and video compression applications
… image/video information. There are various transformation techniques used for data compression. Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT) are the most commonly used transformation. DCT has high energy compaction property and requires less computational resources. …
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Wavelets for approximate Fourier transform and data compression
… has two parts. In the first part, we develop a wavelet-based fast approximate Fourier transform algorithm. The second part is devoted to the developments of several wavelet-based data compression techniques for image and seismic data. We propose an algorithm that uses the discrete wavelet …
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Wavelet Factorization and Related Polynomials
… that allow for efficient implementation of the discrete wavelet transform (DWT) for the algorithms of Daubechies and Sweldens and Mallat. Nearest neighbor lifting is a specific form of the general lifting scheme that improves the lifting algorithm by optimizing the number of efficient memory …
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An FPGA-based Run-time Reconfigurable 2-D Discrete Wavelet Transform Core
… design process description of a two-dimensional discrete wavelet transform (DWT) core using the JBits run-time reconfigurable FPGA design tool suite. Several aspects of the design process are discussed, including implementation, simulation, debugging, and hardware interfacing to a reconfigurable …
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Detection Of The R-wave In Ecg Signals
… ECG recordings from the MIT-BIH database. The Discrete Wavelet Transform (DWT) forms the heart of the algorithm providing a multi-resolution analysis of the ECG signal. The wavelet transform decomposes the ECG signal into frequency scales where the ECG characteristic waveforms are indicated by …
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Astronomical image manipulation in the transform domain
… bandwidth. Among many image compression schemes, transform coding is a widely used coding method. Traditionally, processing a compressed image requires decompression first. Following manipulations, the processed image is compressed again for storage. To reduce the computational complexity and …
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Analysis of Wavelet Based Alternatives for OFDM
The objective of this thesis is to analyze wavelet based alternatives for orthogonal frequency division multiplexing (OFDM) and find whether a better system performance is achieved when compared to the discrete Fourier transform (DFT)-based OFDM. We analyze DFT, discrete wavelet transform (DWT), …
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Modeling and identification of time-varying systems - A wavelet approach
… (TV) system impulse responses based on a wavelet approach. This approach permits representation of a time-varying system impulse response in the auxiliary domains, commonly referred to as the transform domains. The latter includes the well-known discrete wavelet transform (DWT) as well as …
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A comparison of discrete cosine transform and discrete wavelet transform algorithm in watermarking against common attacks
… there is no comparison documented done between Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT). In this report, the DCT watermarking algorithms and DWT watermarking algorithms were compared based on robustness and imperceptibility criteria. With DCT, the watermark bits were …
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A comparative study of watermarking techniques in spatial and frequency domains
… these documents can be duplicated, modified, transformed, and diffused very easily. As a result, a watermark that is embedded into the digital data cannot be distinguished from the data itself. Upon request, the watermark can be extracted to prove authorized ownership. In this research, an …
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Image interpolation and denoising in discrete wavelet transform domain
… and processing time, manipulating images in the transform domain, which is possible, is an efficient solution; The uniform wavelet thresholding is one of the most widely used methods for image denoising in the Discrete Wavelet Transform (DWT) domain. This method, however, has the drawback of …
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Orthogonal vs. Biorthogonal Wavelets for Image Compression
… 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 …
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Lossy compression and real-time geovisualization for ultra-low bandwidth telemetry from untethered underwater vehicles
… time-series science data based upon the Discrete Wavelet Transform (DWT) is explained, a number of low-bitrate image compression techniques are compared, and a novel user interface for reviewing transmitted telemetry is presented. Each component is motivated by science data from a variety …
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Hand (Motor) Movement Imagery Classification of EEG Using Takagi-Sugeno-Kang Fuzzy-Inference Neural Network
… includes Blind Source Separation (BSS) and the Discrete Wavelet Transform (DWT), and the feature translation stage includes the Takagi-Sugeno-Kang Fuzzy-Neural Network (TSKFNN). Performance of the proposed model corresponds to an average classification accuracy of 79.4 % for 40 subjects, which …
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Power Transformer Partial Discharge (PD) Acoustic Signal Detection using Fiber Sensors and Wavelet Analysis, Modeling, and Simulation
… The signal analysis employs the application of wavelet-based denoising technique to remove the noises, which mainly came from vibration, EMI, and light sources, embedded in the PD signal. The denoising technique includes the discrete wavelet transform (DWT) decomposition, thresh-holding of …
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Improved thresholding and quantization techniques for image compression
… compression is proposed. Firstly, the generated wavelet coefficients obtained from the Discrete Wavelet Transform (DWT) process are thresholded by the proposed Standard Deviation-Based Wavelet Coefficients Threshold Estimation Algorithm. The proposed algorithm estimates the best threshold value …
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Combined robust and fragile watermarking algorithms for still images. Design and evaluation of combined blind discrete wavelet transform-based robust watermarking algorithms for copyright protection using mobile phone numbers and fragile watermarking algorithms for content authentication of digital still images using hash functions.
… authentication for still images. New blind transform domain block based algorithms using one-level and two-level Discrete Wavelet Transform (DWT) were developed for copyright protection. The mobile number with international code is used as the watermarking data. The robust algorithms used …
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Discrete Wavelet Methods for Interference Mitigation: An Application To Radio Astronomy
The field of wavelets concerns the analysis and alteration of signals at various resolutions. This is achieved through the use of analysis functions which are referred to as wavelets. A wavelet is a signal defined for some brief period of time that contains oscillatory characteristics. Generally, …
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A Comparison of Wavelet and Simplicity-Based Heart Sound and Murmur Segmentation Methods
… separate segmentation techniques based on the discrete wavelet transform (DWT) and the simplicity transform are integrated into a MATLAB software system that is capable of automatically detecting and classifying sound segments.</p> <p>The performance of the two segmentation methods for …
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The discrete wavelet transform as a precursor to leaf area index estimation and species classification using airborne hyperspectral data
… hyperspectral data for vegetation applications. Discrete wavelet transform (DWT), through multiresolution analysis, offers oppurtunities both to reduce dimension and convey information at multiple spectral scales. In this study, we investigated the utility of the Haar DWT for AVIRIS hyperspectral …
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