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 19 of 19 for “"signed distance"”.
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Signed distance registration for depth image sequence
… of depth data. Thus, from our analysis of ideal signed distance functions, we propose a new method for finding the closest point to the surface given a signed distance function and its gradient. Utilizing Implicit Moving Least Squares (IMLS) and our analysis, we propose a new algorithm that …
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Differentiable volume rendering using signed distance functions
… to represent geometry within the scene as a signed distance function. We also present methods for performing gradient descent upon distance fields while preserving Lipschitz continuity. Unlike most differentiable mesh-based renderers, our renderer can optimize between geometry of different …
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A GPU Accelerated Signed Distance Voxel Modeling System
… of solids represented by interpolated grids of signed distance values. The basic format of values on a grid is consistent with the format of an image stack that would be obtained from a volumetric imaging system such as magnetic resonance, positron emission tomography (PET), etc. or sent to a …
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Mesh Differentiable Rendering for Real-World Scenes
… these shells are extracted from an underlying signed distance field. Then, the shells are independently rasterized and the resulting images are alpha-composited using opacities derived from the shells' per-vertex signed distance values. Notably, the shells' vertex positions are updated only via …
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Universal Atrial Coordinate (UAC) for Wall Motion Deep Learning
… (UAC) system. Wall motion, quantified from Signed Distance Fields (SDF) and decomposed via fast Fourier transform (FFT), showed coordinated low-frequency contraction in SR and reduced amplitude with higher-frequency content in AF. The framework enables anatomy-independent motion comparison …
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Robust object pose estimation with point clouds from vision and touch
… articulated object tracker based on signed-distance functions. This tracker runs at 12 Hz using an online depth reconstruction algorithm for the GelSight tactile sensor and a modified second-order update for the tracking algorithm. The tracker provides robust pose estimates of small …
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Manufacturability and Analysis of Topologically Optimized Continuous Fiber Reinforced Composites
… concepts from elementary geometry and the Signed Distance Function of a topologically optimized domain. The manufacturable fiber paths are represented using Non-Uniform Rational Basis Splines, which can be readily conveyed to a 3D-printer.</p> <p>The second algorithm then calls a meshing …
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Acceleration of Eulerian Multi-Material Methods on Highly Parallel Compute Architectures
… a narrow band, the Ghost Fluid Method (GFM), and signed-distance function generation from multiple external geometry file types. Additionally, we present the main problems involved in scaling multi-material interaction simulations across multiple GPUs, and provide solutions to these problems which …
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On analysing deformable (moving) objects
… and flexible approach which is particularly designed to extract deformable timely shape sequences. It is also recognised that existing methods are either too general, and thus inaccurate, or too specific, thereby limited in usability.<br/><br/>This thesis suggests a learning model for gait …
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From Bones to Bytes
… sheep and gazelle tali, while the newly proposed signed distance field descriptor (SDFD) emerged as a strong balance between performance, runtime, and interpretability. In summary, this thesis demonstrates that computational methods can meaningfully augment archaeozoological analysis across …
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Variational multiscale method for coupled systems: free-surface flows and stratified turbulence
… on the implicit interface marker (e.g., signed distance field) results in an interface that traverses through the elements. Applying VMS method to the coupled system results in an interface stabilization term. It is shown that the structure of the stabilization term leads to the so-called …
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Algebraic level sets for CAD/CAE integration and moving boundary problems
… functions are typically dependent on the distance from the evolving boundaries. For boundaries defined by free form curves or surfaces, the distance fields have to be constructed numerically. This may require either a polytope approximation to the boundary and/or an iterative solution to …
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Vector Distance Transform Maps for Autonomous Mobile Robot Navigation
… environments can be represented using the vector distance transform for mobile robot localization, and show that it is a superior representation compared to alternatives such as occupancy grid maps and other distance transform variants such as the unsigned distance transform and the signed …
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Computational Fluid Dynamics with Embedded Cut Cells on Graphics Hardware
… We implement a fast and robust narrow band signed distance field generator for graphics cards based on the Characteristic/Scan Conversion algorithm for stereolithography files. The thesis presents an augmented approach to handle commonly occurring complex configurations and we show that the …
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Quasi-Monte Carlo and Picard Iteration Algorithms for the Nonlinear Hydrodynamics, Dynamics and Controls of Wave Energy Converters
… A mesh-free geometric representation using signed distance functions circumvents the numerically sensitive mesh-mesh surface intersection at each time step, and a continuously differentiable boundary blur accelerates the QMC convergence. These algorithms have been implemented in a …
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Hybrid modelling of heterogeneous volumetric objects.
… objects are boundary representation, distance-based representations, function representation and voxels. These representations work well for modelling homogeneous (solid) objects but they all have significant drawbacks when dealing with heterogeneous objects. In particular, boundary …
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Multiphysics Model of Hypervelocity Impact and Impact Induced Plasma Formation
… An extended level-set method with dual signed distance functions is employed to track interfaces, accommodating large deformation, contact, and separation between materials. The Euler equations are solved using a high-resolution finite volume method. Interfacial fluxes are computed using …
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Image restoration from noisy and limited measurements with applications in 3D imaging
The recovery of image data from noisy and limited measurements is an important problem in image processing with many practical applications. Despite great improvements in imaging devices over the past few years, the need for a fast and robust recovery method is still essential, especially in fields …