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 16 of 16 for “"aberration correction"”.
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Adaptive Aberration Correction for Holographic Projectors
… Freeman designed a method to correct arbitrary aberrations. As ingenious as the method was, the calculations were extensively lengthy. Addressing this issue, a variant of OSPR suited for correcting spatially-varying aberration is presented. The algorithm combines the approaches of Cable, Buckley …
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New Approaches to Aberration Correction in Medical Ultrasound Imaging
… operators may be able to correct for most of the aberration encountered in soft tissues; that increasing aperture should not be viewed merely as a source of aberration, but as an opportunity to more fully correct it; and that the noise penalty for using complete data sets may not be as severe as …
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Tri-phase emulsions as tunable liquid lenses with aberration correction
… in fluid lens design is the minimization of aberrations that are related to refraction of light at spherical interfaces. These aberrations can in principle be compensated by systematic arrangement of multiple spherical interfaces in succession within a compound lens. Adapting this approch to …
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Computational optical coherence tomography for polarization-sensitive imaging, aberration correction, and wavefront measurement
… wavefront is often distorted by defocus and aberration, from either the imaging system or the sample itself, leading to poor image quality. Through a careful consideration of the optical theory and imaging hardware, computational imaging methods can correct these distortions through creative …
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Minimizing electron optical aberrations
"This thesis deals with topics of aberration reduction in high voltage ("""" 100 k V) electron optical instruments, especially used for lithography (SCALPEL) and high resolution electron microscopy (HREM). Since the invention by Berger and Gibson [1) in 1989, SCALPEL (SCattering with Angular …
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Demonstrating Reflectarray Behavior At Infrared
… stacking, and encourage direct integration of aberration correction. To demonstrate the feasibility of utilizing reflectarray technology at infrared (IR), a simple SMIR proof of concept has been successfully designed, fabricated, and tested. The SMIR is comprised of three independent arrays or …
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Direct ray tracing for low energy electron microscopy
… optical systems. It was used to calculate the aberration probe size of a low voltage scanning electron microscope mixed field objective lens, for which conventional methods of paraxial-perturbation breakdown. It was also used to plot through-the-lens scattered secondary electrons in such …
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Adaptive optics, aberration dynamics and accomodation control. An investigation of the properties of ocular aberrations, and their role in accomodation control.
… to study the dynamic correlation of ocular aberrations; and the application of an adaptive optics (AO) system to investigate the effect of the manipulation of aberrations on the accommodation control. The binocular SH sensor consists of one laser source and one camera to reduce system cost …
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In vivo human computed optical interferometric tomography
… Computed imaging techniques such as defocus and aberration correction in optical interferometric tomography, though, have remained in the research stage and have yet to become clinically-useful tools. One major challenge to be overcome for widespread acceptance is that of motion, or stability. As …
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Multivariate Analysis for Scanning (Transmission) Electron Diffraction
… research. The technologies of beam control, aberration correction, signal collection, and data processing have all improved in recent years, leading to a move away from the acquisition single-variable images. Instead it is increasingly common, in the field of analytical S(T)EM, for whole …
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Computational imaging in biology
… imaging, suppression of multiple scattering and correction of heavy optical aberrations, and label free contrast enhancement. Single pixel imaging allows for imaging at high speeds and extended wavelengths compared to traditional cameras. Pared together with computational and inverse problem …
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Prototyping Blue Phase Wavefront Correctors for Astronomical Adaptive Optics
… developed in the field of astronomy for the correction of aberrations introduced by the atmosphere when observing stars, planets and deep sky objects using telescopes based on Earth. This correction is usually applied with deformable mirrors, which have the benefit of being polarisation and …
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Adaptive optics stimulated emission depletion microscope for thick sample imaging
… thickness of biological structures, the aberrations increase and signal-to-noise (SNR) decreases. This becomes even more evident in the super-resolution imaging, as the nanoscopic techniques are especially sensitive to aberrations and low SNR.<br/><br/>The aim of this work is to propose …
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Atomic resolution studies of oxide superlattices and ultrathin films
… techniques have been significantly improved by aberration correctors, which reduce the probe size to 1 Å, or less. Aberration correctors have thus made it possible to resolve individual atomic columns, and possibly probe the electronic structure at atomic scales. Separately, using electron probe …
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Quantitative Automated Object Wave Restoration in High-Resolution Electron Microscopy
… of new methods for determining the relative aberrations in a set of images and the absolute symmetric aberrations in the restored wave. Both are based on the analysis of the phase information in the Fourier domain and give each Fourier component a weight independent of its strength. This …