Wiener Filter
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Novas propostas em filtragem de projeções tomográficas sob ruído Poisson
In this dissertation we present techniques for filtering of tomographic projections with Poisson noise. For the filtering of the tomogram projections we use variations of three filtering techniques: Bayesian estimation, Wiener filtering and thresholding in Wavelet domain. We used ten MAP estimators, each estimator with a diferent probability density as prior
Publicado em: 2010
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2. Structural damage detection using time series analysis and piezoelectries actuators and sensors / Detecção de danos estruturais usando analise de series temporais e atuadores e sensores piezeletricos
This work proposes a novel approach to detect and locate incipient damage in structures by using only acceleration responses and coupled piezoelectric actuators and sensors. Though the major focus in smart damage detection is given by on the monitoring of the electrical impedance in the frequency domain, the current contribution applies a novel technique bas
Publicado em: 2008
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3. Desenvolvimento de um sistema computacional para utilização em procedimentos de controle de qualidade em equipamentos mamográficos / Development of a computational system for quality control procedures on mammographic equipment
The present work consists on developing a computational methodology to provide information regarding to mammographic equipment quality evaluation. This investigation have taken into account, beyond the required operational parameters, such as kVp, electrical current, focal point, dose, exposition time, half-value layer, the influence of the film digitizer ut
Publicado em: 2007
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4. Transfer function based methodology to preprocessing digital mammographic image and its application on computer-aided diagnosis schemes / Metodologia baseada nas funções de transferência para pré-processamento de imagens mamográficas digitais e sua aplicação em esquema computacional de auxílio ao diagnóstico
The purpose of this work is to evaluate the quality of radiological equipment and their images in order to use these evaluations to improve the performance of a computer-aided diagnosis (CAD) scheme. The mean idea is about the development of image processing techniques to enhance digital mammograms according to the characteristics of the X-ray unit used for
Publicado em: 2005
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5. Restauração de imagens de microscopia confocal utilizando técnicas POCS.
Computer Optical Sectioning Microscopy (COSM) is widely used in morphological studies of cellular structures. COSM appears as a great challenge to digital image processing, because the large size of the three-dimensional files. The major problem in COSM is the blurring, which practically turn the image unusable without the use of digital image processing tec
Publicado em: 2005
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6. Análise da aplicação do filtro wiener ao tratamento de dados da radiação cósmica de fundo obtido pelo telescópio / Analysis of the aplication of a wiener filter to the cosmic microwave background data processing from the beast telescope
Este trabalho apresenta a implementação do filltro Wiener para remoção de um ruído proporcional ao inverso da freqüência (x 1/f) presente nos dados do experimento BEAST, estabelecendo uma comparação entre seu desempenho e o do filtro atualmente utilizado (Passa altas) na análise de dados. O ruído 1/f aumenta a potência total do sinal em baixas fr
Publicado em: 2004
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7. Application of wiener filter to electromyography signals treatment / Aplicação do filtro de WIENER para tratamento de sinais eletromiográficos
A eletromiografia consiste no estudo do movimentos dos músculos através dos sinais elétricos emitidos pelos mesmos. Esses sinais são captados por meio de eletrodos (de surpefície ou de agulha), sendo muito suscetíveis a variações e interferências não relacionadas diretamente com o movimento muscular (ruídos). Visando obter dados qualitativamente c
Publicado em: 2003
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8. Basilar Membrane Responses to Noise at a Basal Site of the Chinchilla Cochlea: Quasi-Linear Filtering
Basilar membrane responses to clicks and to white noise were recorded using laser velocimetry at basal sites of the chinchilla cochlea with characteristic frequencies near 10 kHz. Responses to noise grew at compressive rates and their instantaneous frequencies decreased with increasing stimulus level. First-order Wiener kernels were computed by cross-correl
Springer-Verlag.
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9. Quantal nature of synaptic transmission at the cytoneural junction in the frog labyrinth.
1. The mechanism of transmitter release at the cytoneural junction of the frog posterior canal was investigated by recording intracellularly subthreshold postsynaptic potentials (EPSPs), and performing a statistical analysis of time intervals and peak amplitudes. In single units EPSPs display highly variable size, so it is not clear whether they are generate
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10. Functional identification of the input-output transforms of motoneurones in the rat and cat.
1. We studied the responses of rat hypoglossal and cat lumbar motoneurones to a variety of excitatory and inhibitory injected current transients during repetitive discharge. The amplitudes and time courses of the transients were comparable to those of the synaptic currents underlying unitary and small compound postsynaptic potentials (PSPs) recorded in these
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11. Spike Inference from Calcium Imaging Using Sequential Monte Carlo Methods
As recent advances in calcium sensing technologies facilitate simultaneously imaging action potentials in neuronal populations, complementary analytical tools must also be developed to maximize the utility of this experimental paradigm. Although the observations here are fluorescence movies, the signals of interest—spike trains and/or time varying intracel
The Biophysical Society.