Browsing by Subject "Registration"
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Item (2016-2017) Joint Resolution 1: A Joint Resolution in Support of Adding a "Past Syllabi" and "CV" Tab to the UT Registration Web Page(2016-10-18) Dror, Jonathan; Walsh, BishopItem Perception pipeline for remote tunnel inspection rover(2019-05) Mcmahon, Conor Alexander; Landsberger, Sheldon; Pryor, Mitchell WayneArchitectural structures require routine structural inspections, and these checks are increasingly performed by remote robotic systems. Inspections often meet all of the traditional "three D's" of robotics - Dull, Dirty, and Dangerous - and may be highly suited to automation. Underground tunnel systems present a particularly important opportunity for robots because these systems may have environmental hazards which make human deployment untenable. Unfortunately, tunnels are also a challenging environment for robots because they feature high self-similarity which makes localization along the tunnel axis difficult, in particular for cases where rough terrain renders odometry information unreliable. Here a platform-agnostic pipeline is presented for tunnel mapping and inspection. This system features tools to automatically segment the various concrete surfaces of the tunnel and individually analyze them for damage. A novel feature-based registration routine is also presented to overcome the localization challenges inherent in tunnels. The pipeline was validated using a LiDAR-based sensor tree and its performance in terms of registration and depth mapping accuracy was extensively tested. The registration methods utilized here do not depend on odometry or the use of registration targets and were shown to outperform contemporary approaches which are standard in industry.Item Spectral recomposition and multicomponent seismic image registration(2012-05) Cai, Yihua, 1978-; Fomel, Sergey B.; Hardage, Bob A.; Wilson, Clark R.Spectral recomposition splits a seismic spectrum into Ricker components. It provides a tool for imaging and mapping temporal bed thicknesses and geologic discontinuities. I propose an application of separable, nonlinear, least-squares estimation in spectral recomposition. Employing the Gauss-Newton method, this approach estimates fundamental signal parameters such as peak frequencies and amplitudes. I applied spectral recomposition to multicomponent seismic data, which provides new perspectives of seismic attributes and multicomponent data interpretation. Correlating S-wave reflection with P -wave reflection is one of the very first steps in multicomponent data interpretation. In a given stratigraphic interval of a geologic section, registration correlates P and S-wave profiles to determine ts /tp ratios, which are equivalent to Vp /Vs ratios for vertical propagation paths. The registration process is largely driven by the availability of dipole sonic logs. However, dipole sonic logs are not as common as standard sonic logs and tend to be affected by various borehole factors. Therefore, new techniques are needed for accurate P P and P S correlation and registration. Assuming P P and P S reflection events have been correctly positioned laterally in migrated images, and the difference between P P wave image and P S wave image can be explained only by vertical transformation, I adopt a multistep approach to register PP and PS images automatically. Setting PP time as a coordinate system, I was able to squeeze P S traces accordingly while keeping the signal pattern of P S wave data. Local seismic attributes, such as the local similarity, help improve registration accuracy.