Anisotropic Diffusion
Mostrando 1-12 de 30 artigos, teses e dissertações.
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1. Enhancing quality in Diffusion Tensor Imaging with anisotropic anomalous diffusion filter
Abstract Introduction: Diffusion tensor imaging (DTI) is an important medical imaging modality that has been useful to the study of microstructural changes in neurological diseases. However, the image noise level is a major practical limitation, in which one simple solution could be the average signal from a sequential acquisition. Nevertheless, this approac
Res. Biomed. Eng.. Publicado em: 12/09/2017
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2. Aplicação da técnica de elipsometria de emissão para caracterização de materiais luminescentes
In this work we demonstrated the potential of the emission ellipsometry in the scope of the Stokes theory for electromagnetic field to the photophysics study of luminescent materials, in addition we introduce a new methodology using an achromatic quarter-wave plate. Moreover, the use of linearly polarized light allowed "selectively" the study of various phot
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/02/2012
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3. Filtro difusão-mediana com determinação automática dos parâmetros com aplicações em sinais de ECG e sensor piezoelétrico. / Diffusion-median filter with automatic determination of parameters with applications in ECG signals and piezoelectric sensor.
O objetivo deste trabalho é filtrar sinais corrompidos por ruído Gaussiano ou impulsivo, preservando a amplitude e a morfologia do sinal original. Normalmente, um filtro linear é utilizado nesta tarefa, porém este filtro altera significativamente as amplitudes e as bordas dos sinais, bem como insere atrasos no sinal. Mostra-se neste trabalho que a difus�
Publicado em: 2009
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4. Intravascular ultrasound: tridimensional quantification and analysis / Análise e quantificação tridimensional em imagens de ultra-som intravascular
INTRODUCTION: Several efforts for in vivo atherosclerotic plaque estimation has been realized worldwide. Current methods for related application are based on spectral analysis of backscattered ultrasound signals before intravascular image formation (IVUS), once there is not available techniques to perform composition analysis only from IVUS images. On this s
Publicado em: 2009
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5. Utilização de equações diferenciais parciais para eliminação de ruídos e detecção de bordas
The edge detection of digital images is a research field that has attracted great interest from the scientific community. Their applications go from the automatic inspection and quality control of industrial piece to the diagnosis of malignancy of cancerous tumors. However, many existing edge detectors have problems related to false edge detection. In this c
Publicado em: 2008
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6. Dispersão de nanopartículas de látex em um cristal líquido liotrópico / Dispersion of nanoparticles of latex in the lyotropic liquid crystal
In this work, we studied the dynamics of agglomeration and dissociation of latex particles when inserted into a lyotropic liquid crystal. This liquid crystal is a ternary system formed by potassium laurate, decilamonium chloride and water, presenting uniaxial calamitic and discotic nematic phases (NC e ND, respectively) and a biaxial nematic phase NB. The la
Publicado em: 2008
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7. Simulação de espectros de ressonância paramagnética eletrônica (RPE) através do programa NLSL
EPR users often face the problem of extracting information from frequently low-resolution and complex EPR spectra. Simulation programs that provide a series of parameters, characteristic of the investigated system, have been used to achieve this goal. This work describes the general aspects of one of those programs, the NLSL program, used to fit EPR spectra
Química Nova. Publicado em: 2007-10
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8. Simulação numérica para difusão anisotrópica / Numerical simulation to anisotropic diffusion
The present work build a computational model using the finite volumes method for unstructured meshes, with the purpose of calculating the hydraulic load in a porous medium, considering it material non - homogeneous and anisotropic. The Anisotropy is a characteristic of many materials found in the nature and it depends on the property studied in this material
Publicado em: 2006
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9. Robust anisotropic diffusion filtering of functional magnetic resonance imaging. / Ressonância magnética funcional com filtragem pela difusão anisotrópica robusta.
Esta dissertação apresenta os principais métodos estatísticos para analisar as séries temporais de fMRI com o objetivo de detectar regiões ativadas e caracterizar o erro envolvido nessa decisão. Na análise de imagens funcionais, devido à baixa razão sinal-ruído, torna-se necessário o uso de técnicas elaboradas de processamento. O resultado da ap
Publicado em: 2005
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10. Nanoestruturas e efeitos de tamanho na epitaxia de compostos III-V
In this work we discuss issues related to two different methods to obtain epitaxially grown semiconductor nanostructures. The samples were grown by Chemical Beam Epitaxy (CBE) and characterized by High Resolution Transmission Electron Microscopy (HRTEM), Atomic Force Microscopy (AFM) and Reflection High-Energy Electron Diffraction (RHEED). In the first part
Publicado em: 2001
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11. Propriedades Ópticas de Semicondutores Orgânicos à Base de Polímeros Emissores de Luz / Optical proprieties of organic semiconductors based on light emitting polymers.
In this work, we studied the optical proprieties of absorption and emission of luminescent conjugated polymers based on poly(p-phenylene vinylene) (PPV). This material was processed in thin films by casting, spin-coating, self-assembled (SA) e Langmuir-Blodgett (LB) techniques, available in the Grupo de Polímeros Bernhard Gross, where the samples were chara
Publicado em: 2001
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12. ENHANCED DIFFUSION AND ELECTRICAL BEHAVIOR OF MISFIT DISLOCATIONS IN EPITAXIAL Si/Si(Ge)
This dissertation addresses enhanced or \"pipe\" diffusion of dopants along localized misfit dislocations (MD) using a \"model\" misfit dislocation structure at epitaxial Si/Si(Ge) interfaces and provides basic information on the merits of applicability of novel bandgap engineered devices. Pipe diffusion is modeled and explored to create pipe-like one dimens
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 1994