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.
Results
Showing 1 to 20 of 78 for “"image contrast"”.
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Computational Techniques for Advancing Photoacoustic Microscopy
… metabolism. However, challenges related to image contrast, spatial resolution, and functional analysis hinder its broad applications in biomedicine. This dissertation presents innovative computational techniques to address these challenges. Specially, a sparse coding-based technique is …
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Developments in 2D NMR relaxometry and its application to biological tissue
… 2D relaxation spectra can be used to optimise image contrast, which is an outstanding problem in clinical MRI. Indeed clinical MRI lacks well established and accurate methods for optimising image contrast and fails to exploit much of the potential available to the NMR practitioner. In this …
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Diffusional effects in magnetic resonance imaging and microscopy
… content of nuclear magnetic resonance (NMR) images have recently been sought through the development of new contrast mechanisms for magnetic resonance imaging (MRI) and NMR microscopy. This thesis addresses the role of molecular diffusion in NMR and develops new methods to obtain image …
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Monte-Carlo simulations of positron emission tomography based on liquid xenon detectors
… Focus 120). A NEMA-like cylinder phantom and an image contrast phantom were simulated with both scanners to compare performance characteristics. A Compton reconstruction algorithm was developed for the LXe scanner, and its performance and limitations studied.
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The characterization of a mouse model of transient stroke using ex vivo MR microscopy and in vivo MR imaging
… therapeutic treatment of stroke. Currently, MR contrast agents have been widely used in clinics for disease diagnosis and treatment evaluation, and in basic research to achieve better anatomical structure visualization and to understand pathological mechanisms of various human diseases in animal …
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DEVELOPMENT OF NON-CONTACT MICROSPHERE CONFOCAL SCANNING MICROSCOPE
… to 110 nm, the axial resolution to 100nm and image contrast to 71%, while retaining the key features of the conventional confocal microscope, such as no damage to samples, 3D in-vivo imaging and the ability to work in different environments.
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Haze measurements through image analysis
… approaches to haze measurements are explored. Images of haze were taken in fifteen minute intervals in June, 2013. These images were analyzed to obtain image contrast, and power spectral density functions. The power spectral density functions were characterized by maximum power, full width at …
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Parallel radiofrequency transmission for 3 Tesla and 7 Tesla magnetic resonance imaging
… imaging technique with high soft tissue contrast. MR scanners are characterized by their main magnetic field strength. Commercially available clinical MR scanners commonly have main field strengths of 1.5 and 3 Tesla. Researchers increasingly explore clinical benefits of higher field …
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Design, development and characterization of an integrated multispectral polarimetric sensor system
… sensor, such a sensor is anticipated to improve image contrast with sensor-fusion post processing. In addition, it will offer portability and robustness because of its integrated nature.
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An optical/digital incoherent image processing system for an extended depth of field
… of the system, this method results in a loss of image contrast. An annular pass filter can be used to restore this loss in contrast. A simple hybrid optical/digital image processing system in which a TV camera is coupled with an annular aperture is considered. The annular-pass filtering to …
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SECONDARY ELECTRON SPECTROSCOPY INSIDE THE SCANNING ELECTRON MICROSCOPE AND ITS MATERIAL SCIENCE APPLICATIONS
… electrons inside it, used mainly for topographic image of a sample’s surface, contain valuable information in the emitted energy spectrum. In this thesis, we extract out this spectral information by using an electron energy analyser attachment. We first present experimental secondary electron (SE) …
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Model-based quantitative combinatorial optical microscopy for extracting clinical imaging biomarkers
… techniques based on unique, yet complementary, contrast mechanisms have emerged. While each imaging modality is able to elucidate certain properties of the particular sample under study, an integrated approach in which all modalities are acquired in a simultaneous, co-registered manner can prove …
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New considerations for compact cyclotrons
… that the ⁷Li(p,n)⁷Be reaction could improve image contrast by employing a superconducting cyclotron capable of 3.8 MeV, 414 [mu]A proton beam and liquid lithium target.
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Investigation of Advanced Material Through Digital Volume Correlation Measurement Techniques
… with micro-particles to acquire the sufficient image contrast. A rigid body displacement test is then utilized to evaluate the errors associated with each particle, narrow DVC parameters, and select between particles. Utilizing this methodology displacement and strain fields were obtained for …
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MIMO radar: signal processing, waveform design, and applications to synthetic aperture imaging
… (MIMO) radar techniques to improve the image quality and area-coverage rate of synthetic aperture imaging systems. A signal processing architecture for MIMO radar is used to understand the applicability of MIMO for synthetic aperture radar (SAR) and synthetic aperture sonar (SAS) …
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A robust digital image watermarking using repetition codes against common attacks
… using repetition code (3, 1) inside the cover image pixels based on Discrete Cosine Transform (DCT) embedding technique. The proposed methods have undergone several simulation attacks tests in order to check up and compare their robustness against various attacks, like salt and pepper, speckle, …
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Ultrahigh resolution optical coherence tomography for the detection of early stage neoplastic pathologies
… promise to improve tissue differentiation and image contrast. Previous ex vivo, benchtop ultrahigh resolution OCT imaging studies suggest that differentiation of architectural morphology associated with pathology is feasible. This thesis covers the development and investigation of ultrahigh …
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Real-time quantitative phase imaging for cell studies
… Several methods have been developed to improve contrast in cell imaging, including use of exogenous contrast agents such as fluorescence microscopy, as well as utilizing properties of light-specimen interaction for optics design, to reveal the endogenous contrast, such as phase contrast …
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Using a voxel-based krogh cylinder array to simulate microvascular contrast enhancement
… simulate microscopic and voxel-based dynamic contrast enhancement in magnetic resonance imaging. Specifically, errors imposed by the traditional two-compartment model are reduced by introducing a novel Krogh cylinder network. The two-compartment model was developed for macroscopic …
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Polarization-dependent wavelength-selective structures for multispectral polarimetric infrared imaging
… for object detection, object recognition, and image contrast enhancement. Mosaicked multispectral-polarimetric filter technology, using CMOS-type metallo-dielectric grating structures, is presented as a potential solution in which the spectral filtering and polarization filtering functions are …
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