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 40 for “"Wiener Filter"”.
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Robust Implementations of the Multistage Wiener Filter
… with specific emphasis on the multistage Wiener filter (MWF). The MWF is a generalization of the classical Wiener filter that performs a stage-by-stage decomposition based on orthogonal projections. Truncation of this decomposition produces a reduced rank filter with many benefits, for …
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Robust GM Wiener Filter in the Complex Domain
… been used in radar systems for their ability to "filter clutter, interference and jamming signals. One major flaw with early STAP radar systems is the reliance on non-robust estimators to estimate the noise condition. When even a single outlier is present, the earliest STAP radar systems would …
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Information theoretic design of breast sonography
… to readers. Our previous study revealed that the Wiener filter, derived as a stationary approximation of the ideal observer and operating on RF echo data, generally improved discriminability except for one case involving high-contrast lesions. This study explores an adaptive, iterative Wiener …
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Aumento della risoluzione spaziale per il sondaggio di temperatura e umidità da satellite geostazionario mediante radiometria ad onde millimetriche e submillimetriche
… Model System (UW-NMS). Three approaches, Wiener filter, Super-Resolution and Image Fusion have been applied to some representative GOMAS frequency channels to enhance the resolution of antenna temperatures. The Wiener filter improved resolution of the largely oversampled images by a factor …
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BER Modeling for Interference Canceling Adaptive NLMS Equalizer
… in implementation. Conventional adaptive filtering theory suggests the upper bound of the performance of such equalizer is determined by the performance of a Wiener filter of the same structure. However, in the presence of a narrowband interferer the performance of the LMS equalizer is …
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ENHANCEMENT AND RESTORATION OF DUST IMAGES
… of dusty images. This algorithm is based on the Wiener filter, luminance stretching, and a modified homomorphic filter. The Wiener filter is applied to restore image pixels and remove the blur noise. Subsequently, an image is converted from RGB to YCbCr color model. In YCbCr, the luminance is …
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Improving ultrasonic imaging using novel coded excitation techniques
… were assessed. First, it was hypothesized that a Wiener filter could adversely affect the compression performance of coded excitation because it had the potential to boost the harmonics due to nonlinear distortion. When the Wiener filter operated near an inverse filter the harmonics were boosted, …
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Uniform FIR approximation of causal Wiener filters with applications to causal coherence
Leveraging the relationship between Wiener filtering and the coherence function, a version of coherence is defined that captures the causal relationship between WSS processes. This causal coherence is interpreted in a modeling context and used to demonstrate what a frequency dependent measure for …
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Tomographic measurements of barotropic motions
… (Platzman, Curtis, Hansen, and Slater, 1981). A Wiener filter is formulated for estimating the barotropic tides from a basin scale tomographic array. Error analyses indicate an ability to estimate barotropic currents and surface displacements with errors less than 0.01 cm/s and 1 cm, …
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Multiframe Super Resolution with JPEG2000 Compressed Images
… JPEG2000 compression. We focus on the adaptive wiener filter (AWF) method of SR and study the SR performance as JPEG2000 is incorporated in different ways. In particular, we perform compression prior to SR and compare this to compression after SR. We also compare independent frame compression …
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The closed form error expression with Parseval's theorem
The closed form error expression of optimum Wiener filter was first introduced by M. C. Yovit and J. L. Jackson in 1955. Since then, a number of people have proved the validity of this form using almost similar technique but no one has succeeded to extend the Yovit-Jackson's original formula for …
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Model-Based Speech Enhancement
… This is a significant departure from traditional filtering-based methods of speech enhancement. A major challenge with this approach is to estimate accurately the acoustic features (voicing, fundamental frequency, spectral envelope and phase) from noisy speech. This is achieved using maximum …
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Conditional Mechanical Squeezing of a Micromechanical Oscillator Approaching the Quantum Regime
… optomechanical cavity and applying optimal filtering, namely the Wiener filter, to the noisy measurement record to estimate the conditional state. I also present a new technique for locking homodyne detectors using a free-space continuously tunable optical field modulator, enabling rapid …
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A state-space approach to dynamic tomography
… of the convergence of the ensemble Kalman filter, a new method for ensemble Kalman smoothing and theory regarding its convergence, the first four-dimensional reconstruction of electron density in the solar atmosphere, a new method for dynamic tomography called the Kalman-Wiener filter that …
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An investigation into the performance of a power-of-two coefficient transversal equalizer in a 34Mbit/s QPSK digital radio during frequency-selective fading conditions
… of this theory is presented in the form of Wiener Filter theory and the Wiener-Hopf equations. An adaptive equalizer located in a 34MBit/s QPSK digital radio is required to operate at very high speed, and its digital hardware implementation is not a trivial task. In order to reduce the cost …
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Synthetic aperture radar-based techniques and reconfigurable antenna design for microwave imaging of layered structures
… namely; modified piecewise SAR (MPW-SAR) and Wiener filter-based layered SAR (WL-SAR). From imaging system hardware point-of-view, microwave imaging systems require suitable antennas for signal transmission and data collection. A reconfigurable antenna which its characteristics can be …
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Optimum linear single user detection in direct-sequence spread-spectrum multiple access systems
… DS-SS modulation is used, a cyclic form of the Wiener filter provides substantial improvements in performance in terms of bit error rate and user capacity. Furthermore, it is shown, that a special error-criterion should be used to adapt the weights of the filter. The computational complexity of …
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Model-based spectral inference in noisy physical time series: applications in laser linewidth estimation and precision magnetometry
… work’s core. The first presents a parametric Wiener filter- ing framework using a power spectrum equalization (PSE) criterion to deconvolve laser frequency noise spectra from delayed self-heterodyne (DSH) measurements, addressing spectral nulls and measurement noise. The second applies …
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Models predicting the performance of IC component or PCB channel during electromagnetic interference
… jitter in the presence of random jitter. A Wiener filter de-convolution method is also presented for extracting the characteristics of crosstalk induced jitter from measurements of total jitter made when the crosstalk sources were and were not present. The proposed techniques are shown to …
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Denoising via Empirical Bayesian Pursuit
… of the threshold-then-average denoising filter is considered, including proposing alternative eigendomain weightings as well as the derivation of lower bounds on signal concentration in the new eigenframe representation. Following the eigenanalysis of the threshold-then-average denoising …
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