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 13 of 13 for “"Fourier Optics"”.
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Three-dimensional strong acousto-optic interaction theory
… the interaction. The first method is called the Fourier-Optics approach and applies directly to a nondiffracting sound column. An incident light beam propagates through the cell by alternating between interaction and diffraction. The second method is called the Wave-Equation approach because it …
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Numerical modeling and ray tracing of SPatIal Frequency modulation for Imaging
… presents the first full geometric and physical optics characterization of aberrations and the performance of a simple system that implements SPatIal Frequency modulation for Imaging (SPIFI). SPIFI utilizes a chirped frequency mask that modulates the intensity of light along a single axis at a …
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Tailoring the angular and spectral reflectance characteristics of color-dynamic films by modifying their photonic texture and topcoat roughness
… distribution of incident and reflected light. Fourier optics concepts are harnessed for modeling and predicting the optical characteristics of the materials as a function of their photonic texture and topcoat roughness. The model is verified with data obtained by imaging the angular scattering …
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Visual pathology rectification
… Another possible method is the use of geometric optics. Optics describe the properties of a ray of light as it propagates through an optical system. These properties are described in a transfer matrix, which is then used to improve an image for a visual impaired user. Results show that while …
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Terahertz time domain methods for material characterization of layered dielectric media
… phenomena at interfaces, wave propagation and Fourier optics. Because material characterization is an inverse problem solution, optimization and root finding methods were required to that effect. The optimization method utilized was the Nelder-Mead Simplex method while the root finding method …
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Quantification of the Depth-of-Field in a Self-Aligned Focusing Schlieren System
… system is characterized experimentally using a Fourier optics framework based on the modulation transfer function (MTF) and point spread function (PSF). Depth-dependent MTF measurements from a slanted-edge target and PSF measurements from a 100 µm pinhole target show that the depth response of …
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Single Molecule Localisation with Fourier Light Field Microscopy
… are captured using a lenslet array in the Fourier plane of a fluorescence microscope. The 3D localisation of each fluorophore is then computed in post-processing. An in-depth description of the principles of the proposed technique is first presented, followed by an investigation into how …
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Metamaterials for Computational Imaging
… and compressed imaging using the language of Fourier optics, and derive the forward model needed to apply computational imaging to the metaimager system. We describe the details of the metamaterials used to construct the metaimager and their application to metamaterial antennas. The …
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Active hyperspectral imaging of chemicals on surfaces
… imaging was examined using simulations based on Fourier optics and information from sources such as Goodman [6], [17]. Speckle is a limiting factor in hyperspectral imaging because it is noise that scales with the signal, and thus cannot be eliminated by increasing the signal strength. Equations …
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Diffraction-based Optical Architectures for Processing One-dimensional Data
… and actually mark an improvement over classical optics (CO) apparatus. This thesis seeks to answer several of these questions, through a variety of analytic, simulation-based and experimental methodologies. It is shown analytically, first in a scalar and then in a vectorial framework, that …
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Advanced imaging via multiplexed sensing and compressive sensing
… i.e., four-dimensional correlator in Fourier optics. This random lens has much higher light-gathering power and higher imaging quality than other simple implementations, such as coded aperture, random pinhole array and random mirror array. In addition to sparsity and total variation, …
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DEVELOPMENT OF OPTICAL IMAGE ENCRYPTION TECHNIQUES FOR INFORMATION SECURITY
The wide spread use of networking and internet has led to remarkable research efforts in the area of information security. This thesis is to develop new techniques for optical image encryption, and to overcome some existing problems in conventional cryptosystems. Several works have been …
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Low-Cost Spatial Light Modulator for Applications in Free-Space Optical Communication
… (SLMs) are core components deployed for Adaptive Optics (AO) to compensate for atmospheric distortions. AO is an enabling technology for Free-Space Optical Communication, whose performance is severely degraded by the atmosphere. This thesis proposes two low-cost AO strategies: (1) repurposing …