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 20 for “"stray light"”.
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A direct measurement of intraocular stray light.
Thesis: M.S., Massachusetts Institute of Technology, Department of Physics, 1945
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Software and hardware improvements for digital solar magnetograph system
… to improve resolution, eliminate image noise and stray light effect. The efficiencies of different processing methods have been discussed and their Fourier spectra have been analyzed. After noise deduction and stray light elimination, the processed magnetograms have been proved to be much better …
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Development and Improvement of Spectroscopic Techniques for Atmospheric Composition Measurements from Ground and Space
… data produced by the Brewer Spectrophotometer. Stray light in the Brewer instrument causes an underestimation of daily ozone values especially in the northern latitudes where, at certain times of the year, measurements must be made at large solar zenith angles. This section focuses on a …
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Absorption of sunlight by atmospheric sodium
… has been built which is sensitive only to light in a very narrow spectral region near the sodium D-line8. The light is scattered by sodium vapour at low density and the scattered light recorded by a photoelectric spectrometer. The latter resolves the two lines and allows the effect of stray …
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Transition Edge Sensors for Far-Infrared Space Science
… I implement techniques to shield detectors from stray light, stray magnetic fields and electromagnetic interference, critical to realising optimal performance both in ground-based test systems and ultimately in space, with a particular emphasis on thermal design to eliminate stray light. I …
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Bidirectional Reflectance Measurements of Low-Reflectivity Optical Coating Z302
Black coatings essentially absorb incident light at all wavelengths from all directions. They are used when minimal reflection or maximum absorption is desired and therefore are effective in applications that require control of stray light. Our motivation stems from the use of black coating Lord …
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The design and construction of a photoelectric spectrophotometer for analytical research
… monochromator using a helium spectrum tube as a light source, the wave length scale was found to be linear;Seven separate amplifiers were constructed, of which one was finally used. It suffered less from random currents and drift than did the other six, but was still so erratic that results could …
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Crosstalk and Signal Integrity in Ring Resonator Based Optical Add/Drop Multiplexers for Wavelength-Division-Multiplexing Networks
… EMC issues are due to backscatter, crosstalk, stray light, and substrate modes. This thesis has focused on the crosstalk in Optical Add/Drop Multiplexers (OADMs) as an EMC problem. The main research question is: “How can signal integrity be improved and crosstalk effects mitigated in …
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Raman scattering in heavy rare earth metals
Inelastic light scattering spectra were measured in MBE grown single crystal films of Dysprosium, Erbium and yttrium. In order to measure the weak Raman signals of metals a single grating monochromator was designed and constructed and added to an existing double grating monochromator to improve the …
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Optical Characterisation of Astronomical Submillimetre Receivers including ALMA Bands 5 and 9
… resonant cavities are also analysed. A complex stray light baffle structure is introduced within the cavity and its effect upon the system is quantified.
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Improving measurements in perimetry for glaucoma
… instruments to the optical artefact of stray light that might be caused by media opacity. This is clinically important because cataract and degraded optical media is a leading cause of false-referral for glaucoma. This work, being the first of its kind, indicates that the MMDT has …
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Cone Beam Optical Computed Tomography-Based Gel Dosimetry
… inherent difficulty of managing the effects of stray light pertubation in the optical attenuation-to-dose calibration.
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High resolution spectropolarimetric diagnostics of weak, small-scale magnetic fields in the solar photosphere
… GREGOR resolutions and the impact of unpolarized stray light contamination, spatial resolution and signal-to-noise is considered. A LPF exhibiting very similar magnetic flux density at its centre as those observed by the GRIS-IFU is studied. Thus, it is demonstrated that MHD simulations are …
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Predicting Surface Scatter Using A Linear Systems Formulation Of Non-paraxial Scalar Diffraction
… including x-ray and EUV imaging, the design of stray light rejection systems, and reflection modeling for rendering realistic scenes and animations of physical objects in computer graphics. Rayleigh-Rice (small perturbation method) and Beckmann-Kirchoff (Kirchhoff approximation) theories are …
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The Wide-Field Infrared Transient Explorer (WINTER): a new near-infrared time-domain survey
… touches upon all aspects of the instrument, highlighting the major subsystems I directed, including detailed instrument design and modeling, project requirements flowdown, kilonova follow-up science simulations, testing of new detectors alongside the development of custom readout firmware and …
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Evaluation and Application of Max-DOAS Methods for Monitoring Aerosols, NO2, and SO2 in Urban and Industrial Environments
… is challenging due to the effects of stray light, potential interference by O3 absorption, and low solar intensity in wavelength regions where SO2 absorption features are strong. Based on the experiments, the use of a short-pass filter and a fitting window of 307.5 < <319 nm are …
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Measurement of some radiative properties of solar absorber materials
… to use and also allows it to be housed within a light-tight enclosure that minimizes problems with stray light. Extensive measurements have been made using laser sources at λ - 633 nm and λ - 1152 nm on the same set of samples of solar absorbers (selective and non-selective) studied with the …
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Peripher induzierte Pulsation eines fovealen Nachbildes: Nachweis eines weitreichenden neuronalen Effektes
Ich dokumentiere einen bemerkenswerten weitreichenden Effekt der von der Netzhautperipherie auf die Fovea wirkt. Als Sonde verwende ich ein von einem Fotoblitz erzeugtes, foveales Nachbild. Ein solches Nachbild erscheint dunkel, wenn es vor einem hellen Hintergrund gesehen wird, und hell, wenn es …
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Discomfort glare, light scatter, and scene structure
… in working conditions. As part of this process, light in the work place was recognised as an important environmental factor. In the early years of the 20th century it was also recognised that in providing adequate lighting for a particular working environment, there was a need to avoid the …
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GHOST IMAGE ANALYSIS FOR OPTICAL SYSTEMS
… images are caused by the inter-reflections of light from optical surfaces that have transmittances less than unity. Ghosts can reduce contrast, provide misleading information, and if severe can veil parts of the nominal image. This dissertation develops several methodologies to simulate ghost …