2,353 research outputs found
Multi-scale 3-D Surface Description: Open and Closed Surfaces
A novel technique for multi-scale smoothing of a free-form 3-D surface is presented. Complete triangulated models of 3-D objects are constructed automatically and using a local parametrization technique, are then smoothed using a 2-D Gaussian filter. Our method for local parametrization makes use of semigeodesic coordinates as a natural and efficient way of sampling the local surface shape. The smoothing eliminates the surface noise together with high curvature regions such as sharp edges, therefore, sharp corners become rounded as the object is smoothed iteratively. Our technique for free-form 3-D multi-scale surface smoothing is independent of the underlying triangulation. It is also argued that the proposed technique is preferrable to volumetric smoothing or level set methods since it is applicable to incomplete surface data which occurs during occlusion. Our technique was applied to closed as well as open 3-D surfaces and the results are presented here
Multi-Scale Free-Form Surface Description and Curvature Estimation
A novel technique for multi-scale smoothing of a free-form 3-D surface is presented. Complete triangulated models of 3-D objects are constructed at our center [4] and using a local parametrization technique, are then smoothed using a 2-D Gaussian filter. Our method for local parametrization makes use of semigeodesic coordinates as a natural and efficient way of sampling the local surface shape. The smoothing eliminates the surface noise together with high curvature regions such as sharp edges, therefore, sharp corners become rounded as the object is smoothed iteratively. Our technique for free-form 3-D multi-scale surface smoothing is independent of the underlying triangulation. It is also argued that the proposed technique is preferrable to volumetric smoothing or level set methods since it is applicable to incomplete surface data which occurs during occlusion. The technique was applied to simple and complex 3-D objects and the results are presented here
On universal decoherence under gravity: a perspective through the Equivalence Principle
In Nature Phys. 11, 668 (2015) (Ref. [1]), a composite particle prepared in a
pure initial quantum state and propagated in a uniform gravitational field is
shown to undergo a decoherence process at a rate determined by the
gravitational acceleration. By assuming Einstein's Equivalence Principle to be
valid, we demonstrate, first in a Lorentz frame with accelerating detectors,
and then directly in the Lab frame with uniform gravity, that the dephasing
between the different internal states arise not from gravity but rather from
differences in their rest mass, and the mass dependence of the de Broglie
wave's dispersion relation. We provide an alternative view to the situation
considered by Ref. [1], where we propose that gravity plays a kinematic role in
the loss of fringe visibility by giving the detector a transverse velocity
relative to the particle beam; visibility can be easily recovered by giving the
screen an appropriate uniform velocity. We finally propose that dephasing due
to gravity may in fact take place for certain modifications to the
gravitational potential where the Equivalence Principle is violated.Comment: 5 pages, 3 figure
Quantum variational measurement in the next generation gravitational-wave detectors
A relatively simple method of overcoming the Standard Quantum Limit in the
next-generation Advanced LIGO gravitational wave detector is considered. It is
based on the quantum variational measurement with a single short (a few tens of
meters) filter cavity. Estimates show that this method allows to reduce the
radiation pressure noise at low frequencies () to the level
comparable with or smaller than the low-frequency noises of non-quantum origin
(mirrors suspension noise, mirrors internal thermal noise, and gravity
gradients fluctuations).Comment: 12 pages, 4 figures; NSNS SNR estimates added; misprints correcte
Increasing future gravitational-wave detectors sensitivity by means of amplitude filter cavities and quantum entanglement
The future laser interferometric gravitational-wave detectors sensitivity can
be improved using squeezed light. In particular, recently a scheme which uses
the optical field with frequency dependent squeeze factor, prepared by means of
a relatively short (~30 m) amplitude filter cavity, was proposed
\cite{Corbitt2004-3}. Here we consider an improved version of this scheme,
which allows to further reduce the quantum noise by exploiting the quantum
entanglement between the optical fields at the filter cavity two ports.Comment: 10 pages, 7 figure
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