Browsing by Subject "Optical"
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Item Evaluation of a Deep Plan Office Space Daylit with an Optical Light Pipe and a Specular Light Shelf(2009-05-15) Upadhyaya, KapilThis research developed the Optical Light Pipe (OLP) as a feasible solution to solve the problem of insufficient daylighting in deep plan office spaces for predominantly sunny climates. It further combined the OLP with a Specular Light Shelf (SLS) to achieve uniform daylighting. This research was performed with an experimental setup of two 1:4 scale models of deep plan office spaces, modified from an earlier research on optical light pipe at College Station, TX. Blinds and shading devices were installed on the south fa?ade to provide daylight to the front zone of a 20 feet by 30 feet office module. The back zone was daylit by the OLP hidden in the plenum. The existing OLP design was optimized through computer aided ray-tracing. The SLS design was based on an earlier prototype designed at Lawrence Berkeley National Labs (LBNL). Results were based on observations made on clear and cloudy sky days between February 3rd and March 17th. The OLP achieved more than 300 lux of average workplane illuminance for 7.4 hours, when global horizontal illuminance was greater than 40,000 lux. It also achieved 200 lux of illuminance higher than an earlier prototype (Martins-Mogo, 2005) on workplane between 1000hrs and 1630hrs. It exhibited a glare free daylight distribution with luminance ratios well within prescribed limits on most of the vertical surfaces, with a relatively uniform illuminance distribution on back taskplane. OLP was better than windows with blinds and shading at providing diffuse daylight in backzone on a cloudy day, when global horizontal illuminance was greater than 20,000 lux. The OLP used in combination with SLS achieved more than 500 lux of average workplane illuminance for 6 hours, when global horizontal illuminance was greater than 40,000 lux. SLS also produced more uniform illuminance levels on the workplane at all times and on the leftwall at most times. However, it produced non-uniform luminance distribution on walls and ceiling and luminance ratios higher than allowable limits on the sidewall for some morning hours, and hence needed further refinement in design.Item Measuring liquefaction-induced deformation from optical satellite imagery(2014-05) Martin, Jonathan Grant; Rathje, Ellen M.Liquefaction-induced deformations associated with lateral spreading represent a significant hazard that can cause substantial damage during earthquakes. The ability to accurately predict lateral-spreading displacement is hampered by a lack of field data from previous earthquakes. Remote sensing via optical image correlation can fill this gap and provide data regarding liquefaction-induced lateral spreading displacements. In this thesis, deformations from three earthquakes (2010 Darfield, February 2011 Christchurch, and 2011 Tohoku Earthquakes) are measured using optical image correlation applied to 0.5-m resolution satellite imagery. The resulting deformations from optical image correlation are compared to the geologic conditions, as well as field observations and measurements of liquefaction. Measurements from optical image correlation are found to have a precision within 0.40 m in all three cases, and results agree well with field measurements.Item Noise characterization of devices for optical computing(Texas Tech University, 1999-05) Storrs, Samuel MarkOptical computing has proven useful in several specialized applications. However, the general development of optical computing is limited by the computational inaccuracies typically found in optical information processing. One source of these inaccuracies is the noise generation and transformation properties of optical devices. The signal and noise models of optical devices are inadequate for information processing system development and optimization. This is specifically true for spatial light modulators. Progress in optical computing requires more accurate models of these optical devices and their signal and noise characteristics. System modeling of optical devices is complicated by the multiple-port and nonlinear nature of those devices. In this dissertation, the Volterra series model is shown to adequately represent a multiple-port, mildly nonlinear device and is adapted to represent a spatial light modulator. Furthermore, a method is described to experimentally measure the Volterra series model characteristics directly. We develop a three-input, single-output, second-order Volterra series model for a spatial light modulator and describe an experimental method to measure the nonlinear transfer functions using sinusoidal perturbation and synchronous detection with a lock-in amplifier. We review the spectral noise transformation properties of Volterra systems and adapt these results to the multiple-input case. The spectral noise transformation characteristics of optical devices are shown to be calculated directly from the Volterra system model using the nonlinear transfer functions. These techniques are applied to experimentally measure the Volterra series model characteristics of a Hughes 4050 liquid crystal light valve and estimate closed-form expressions for the nonlinear transfer functions. The validity of the model characteristics and spectral noise transformation is demonstrated by comparing predicted spectral noise characteristics with measured device performance.