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 20 of 90 for “"point spread function"”.
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Point Spread Function Engineering in Fluorescence Spectroscopy
Die Synthese von Mikroskopie und Fluoreszenzspektroskopie hat das Mikroskop in ein vielseitiges Werkzeug zur funktionelle Analyse biologischer Systeme verwandelt. In dieser Arbeit wird untersucht, ob und wie kürzlich entwickelte Techniken zur Manipulation von Punktabbildungsfunktionen neue …
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Point Spread Function Engineering for Scene Recovery
… them can be effectively characterized by their point spread functions (PSFs): the intensity distribution on an image sensor as a response to a point light source in a scene. This thesis explores the techniques to characterize, evaluate and optimize computational cameras via PSF engineering for …
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Measuring the point spread function of a light microscope
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
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Three-Dimensional Imaging using a Novel Rotating Point Spread Function Imager
… while simultaneously encoding depth in the point spread function (PSF) itself allows an imaging solution which is less time consuming and less data intensive than the inefficient multiscan based conventional 3D imaging. Light-field cameras also achieve 3D imaging in a snapshot, but at the …
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Long exposure point spread function estimation from solar adaptive optics loop data
… and post-processing with a good estimate of the point spread function (PSF) is required. PSF estimates are impossible to measure directly during solar observations due to the lack of point sources in the field-of-view. Moreover, the highly variable day-time seeing conditions require the estimated …
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Distortion correction in magnetic resonance imaging using the simulated point spread function
… field inhomogeneity. Previously, the measured point spread function (PSF) has been shown to be effective in correcting this distortion. In this work, we reconstruct an image quickly and address the distortion with a point spread function that was generated entirely through simulation using the …
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Point-Spread Function Assessment of SG-DBR Based Swept Source for OCT Imaging
… sources that can affect the quality of the OCT point-spread function (PSF). Based on these noise sources, software is developed to simulate the waveforms in an SS-OCT system and determine the factors that limit width of the PSF central peak and the broadband skirts. Design curves are then …
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Development of Three-Dimensional Super-Resolution Imaging Using a Double-Helix Point Spread Function
… novel techniques, including the double-helix point spread function (DHPSF). A bespoke microscope platform employing the DHPSF transformation was built, achieving ~10 nm lateral and ~20 nm axial localisation precision over a ~4 μm axial depth. Until recently, the DHPSF has been limited by …
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Point Spread Function Reconstruction for the Adaptive Optics System ALFA and its Application to Photometry
… the time- and space-variant nature of the system point spread function (PSF). Generally, the PSF information cannot be taken from the images due to anisoplanacy and/or overexposure of the guide star. It is therefore highly desirable to obtain an independent estimate of the PSF at each position in …
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A low complexity representation of the coherent point spread function in the presence of aberrations and arbitrarily large defocus
… the diffraction integral for evaluating the point spread function. The new method is based on the use of higher order Airy functions along with Zernike and Taylor expansions. Our approach is applicable when we are considering a finite, arbitrary number of aberrations and arbitrary large …
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First Visible Wavelength Lightcurves for the Northern Hemispheres of Titania and Oberon
… the effects of stray Uranian light using point spread function photometry. I modelled Uranus with a Lorentzian with the same full width at half max as the stellar point spread function. I also determined that Uranus’s profile is poorly modeled with a Gaussian or with the stellar empirical …
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Estimation theoretical image restoration
… Poisson noise process, we derived an objective function to estimate the unknown object and point spread function (psf) parameters. We have found that, without constraint enforcement, this blind deconvolution algorithm tended to converge to the trivial solution: delta function as the estimated …
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PSF Sampling in Fluorescence Image Deconvolution
… the effect of convolving the volume with the point spread function. However, these algorithms fall short in several areas such as noise amplification and stopping criterion. In this paper, we try to reconstruct an explicit volumetric representation of the fluorescence density in the sample and …
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Scanning standing-wave illumination microscopy : a path to nanometer resolution in X-ray microscopy
… SWI fluorescence microscopy is developed. The point spread function is remarkably well-suited to Fourier analysis and can be analyzed using graphical techniques. Phase alignment is accomplished by maximizing the intensity of light scattered or fluoresced by a point-like particle using an …
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Extending imaging depth of multiphoton microscopy
… Due to the distortion of the wavefront, the point spread function at the focal point becomes broadened resulting in degraded resolution and lower signal. With an adaptive optics system, which consists of a wavefront camera and deformable mirror, the wavefront distortion can be measured and …
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Generic camera calibration for omnifocus imaging, depth estimation and a train monitoring system
… imaging and 3D scene depth from focus and point spread function calibration. In camera calibration, we propose five new calibration methods for cameras whose imaging model can represented by ideal perspective projection with small distortions due to lens shape (radial distortion) or …
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Accurate characterization of nanophotonic grating structures
… of the device using a Modulation Transfer Function, MTF, technique. MTF is commonly measured using either the line pair method or the slant edge method. This thesis proposes a new method to measure MTF using single pixel illumination and point spread function. Results from the two systems …
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Evaluation of null subtraction imaging and interpolation techniques for ultrasound B-mode
… while the -6 dB beamwidth calculated from the point-spread function may be much smaller than that of conventional techniques, these methods often do not perform as well on the Sparrow test for resolution. Another challenge presented by high-resolution techniques is related to the limited …
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A Search for Low-Amplitude Variability Among Population I Main Sequence Stars
… to the quality of the photometric results. Point Spread Function (PSF) fitting is the best method available for measuring accurate magnitudes within crowded fields of stars, while high-precision differential photometry is the preferred technique for removing the effects of atmospheric …
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Development of an immersion maskless lithography system
… through the experimental reconstruction of its point spread function. Finally, lithography results obtained with the iZPAL system are compared to those obtained with the non-immersion ZPAL system, demonstrating the improvement in resolution, exposure latitude, and depth-of-focus achieved with …
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