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 11 of 11 for “"apodization"”.
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Discrete channel apodization method for the analysis of high-energy x-ray data.
Thesis. 1975. B.S. cn--Massachusetts Institute of Technology. Dept. of Physics.
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Null subtraction imaging technique for biomedical ultrasound imaging
… less distortion and fewer artifacts. In general, apodization is used to lower sidelobes in exchange for increasing the width of the mainlobe and thus decreasing lateral resolution. Null subtraction imaging (NSI) is a nonlinear image processing technique that uses different on-receive apodizations …
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Optical engineering of parallel optical data storage
… that modifications to the reference beam, or apodization, can substantially mitigate the effects of interpage crosstalk, a fundamental noise source in volume holographic storage.
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Nanometer-precision electron-beam lithography with applications in integrated optics
… in the waveguide sidewalls. This design allows apodization of the filter response by lithographically varying the grating depth. Measured transmission spectra show greatly reduced sidelobe levels for apodized devices compared to devices with uniform gratings.
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On-Chip Planar Lens Architectures for Optical Beam Steering
… including double-layer grating designs and apodization schemes for the grating fill-fraction. Both devices are fabricated using a wafer-scale fabrication process and pave the way for two-dimensional optical beam steering with low electronic complexity and a large field of view. Lastly, …
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Gratings With Multiple, Independently Apodized Layers
… of the index modulation, a process called apodization. Apodizing different layers of the grating using different apodizing functions is proposed for adding more degrees of freedom to the design. An approach to designing a two-layer separately apodized grating that yields virtually the same …
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Fast Registration of Tabular Document Images Using the Fourier-Mellin Transform
… eliminated by background removal, meaning that apodization (tapering down to zero at the edge of the image) is not needed for accurate recovery of the rotation parameter, allowing the entire image to be used for registration. An effective new optimization to the median filter is presented. …
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Hybrid mode coupling for enhanced sensing and integrated photonics
… coupler based on a high contrast overlay and apodization for fiber-to-chip that yields greater than 90% coupling efficiency over a broad bandwidth. The efficient diffractive coupling mechanism is due to the presence of a dual-layer grating and constructive interference between the grating …
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Optical Performance and Prototyping of a Liquid Lens Laser Communications Transceiver
… to incorporate diffusers, the benefits of apodization, optimizing the receive path, and strategies to beacon using nutation. Characterization of prototype 1550 nm (optical C-band) optimized lenses from Corning Varioptic are also characterized. Preliminary simulation results for steering …
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Evaluation of null subtraction imaging and interpolation techniques for ultrasound B-mode
In biomedical ultrasound imaging, many attempts have been made to improve the lateral resolution through various adaptive and non-adaptive techniques. While each technique has its advantages and disadvantages, there are some challenges common to all methods. In particular, improvements in lateral …