Title:
Variational image processing algorithms for the stereoscopic space-time reconstruction of water waves
Variational image processing algorithms for the stereoscopic space-time reconstruction of water waves
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Author(s)
Gallego Bonet, Guillermo
Advisor(s)
Yezzi, Anthony
Fedele, Francesco
Fedele, Francesco
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Abstract
A novel video observational method for the
space-time stereoscopic reconstruction of
dynamic surfaces representable as graphs, such
as ocean waves, is developed. Variational
optimization algorithms combining image
processing, computer vision and partial
differential equations are designed to address
the problem of the recovery of the shape of an
object's surface from sequences of synchronized
multi-view images. Several theoretical and numerical paths are discussed to solve the
problem. The variational stereo method
developed in this thesis has several advantages
over existing 3-D reconstruction algorithms.
Our method follows a top-down approach or
object-centered philosophy in which an explicit
model of the target object in the scene is
devised and then related to image
measurements. The key advantages of our
method are the coherence (smoothness) of the
reconstructed surface caused by a coherent
object-centered design, the robustness to noise
due to a generative model of the observed
images, the ability to handle surfaces with
smooth textures where other methods typically
fail to provide a solution, and the higher
resolution achieved due to a suitable graph
representation of the object's surface. The
method provides competitive results with
respect to existing variational reconstruction
algorithms. However, our method is based upon
a simplified but complete physical model of the
scene that allows the reconstruction process to
include physical properties of the object's
surface that are otherwise difficult to take into
account with existing reconstruction
algorithms. Some initial steps are taken toward
incorporating the physics of ocean waves in the
stereo reconstruction process. The developed
method is applied to empirical data of ocean
waves collected at an off-shore oceanographic
platform located off the coast of Crimea,
Ukraine. An empirically-based physical model
founded upon current ocean engineering
standards is used to validate the results. Our
findings suggest that this remote sensing
observational method has a broad impact on
off-shore engineering to enrich the
understanding of sea states, enabling improved
design of off-shore structures. The exploration
of ways to incorporate dynamical properties,
such as the wave equation, in the
reconstruction process is discussed for future
research.
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Date Issued
2011-01-19
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Resource Type
Text
Resource Subtype
Dissertation