751 research outputs found
Non-Rigid Puzzles
Shape correspondence is a fundamental problem in computer graphics and vision, with applications in various problems including animation, texture mapping, robotic vision, medical imaging, archaeology and many more. In settings where the shapes are allowed to undergo non-rigid deformations and only partial views are available, the problem becomes very challenging. To this end, we present a non-rigid multi-part shape matching algorithm. We assume to be given a reference shape and its multiple parts undergoing a non-rigid deformation. Each of these query parts can be additionally contaminated by clutter, may overlap with other parts, and there might be missing parts or redundant ones. Our method simultaneously solves for the segmentation of the reference model, and for a dense correspondence to (subsets of) the parts. Experimental results on synthetic as well as real scans demonstrate the effectiveness of our method in dealing with this challenging matching scenario
Naturalness and stability of the generalized Chaplygin gas in the seesaw cosmon scenario
The seesaw mechanism is conceived on the basis that a mass scale, , and
a dimensionless scale, , can be fine-tuned in order to control the dynamics
of active and sterile neutrinos through cosmon-type equations of motion: the
seesaw cosmon equations. This allows for sterile neutrinos to be a dark matter
candidate. In this scenario, the dynamical masses and energy densities of
active and sterile neutrinos can be consistently embedded into the generalized
Chaplygin gas (GCG), the unified dark sector model. In addition, dark matter
adiabatically coupled to dark energy allows for a natural decoupling of the
(active) mass varying neutrino (MaVaN) component from the dark sector. Thus
MaVaN's turn into a secondary effect. Through the scale parameters, and
, the proposed scenario allows for a convergence among three distinct
frameworks: the cosmon scenario, the seesaw mechanism for mass generation and
the GCG model. It is found that the equation of state of the perturbations is
the very one of the GCG background cosmology so that all the results from this
approach are maintained, being smoothly modified by active neutrinos.
Constrained by the seesaw relations, it is shown that the mass varying
mechanism is responsible for the stability against linear perturbations and is
indirectly related to the late time cosmological acceleration.Comment: 24 pages, 6 figure
Mass varying dark matter in effective GCG scenarios
A unified treatment of mass varying dark matter coupled to cosmon-{\em like}
dark energy is shown to result in {\em effective} generalized Chaplygin gas
(GCG) scenarios. The mass varying mechanism is treated as a cosmon field
inherent effect. Coupling dark matter with dark energy allows for reproducing
the conditions for the present cosmic acceleration and for recovering the
stability resulted from a positive squared speed of sound c_{s}^{\2}, as in
the GCG scenario. The scalar field mediates the nontrivial coupling between the
dark matter sector and the sector responsible for the accelerated expansion of
the universe. The equation of state of perturbations is the same as that of the
background cosmology so that all the effective results from the GCG paradigm
are maintained. Our results suggest the mass varying mechanism, when obtained
from an exactly soluble field theory, as the right responsible for the
stability issue and for the cosmic acceleration of the universe.Comment: 17 pages, 3 figure
Perturbative approach for mass varying neutrinos coupled to the dark sector in the generalized Chaplygin gas scenario
We suggest a perturbative approach for generic choices for the universe
equation of state and introduce a novel framework for studying mass varying
neutrinos (MaVaN's) coupled to the dark sector. For concreteness, we examine
the coupling between neutrinos and the underlying scalar field associated with
the generalized Chaplygin gas (GCG), a unification model for dark energy and
dark matter. It is shown that the application of a perturbative approach to
MaVaN mechanisms translates into a constraint on the coefficient of a linear
perturbation, which depends on the ratio between a neutrino energy dependent
term and scalar field potential terms. We quantify the effects on the MaVaN
sector by considering neutrino masses generated by the seesaw mechanism. After
setting the GCG parameters in agreement with general cosmological constraints,
we find that the squared speed of sound in the neutrino-scalar GCG fluid is
naturally positive. In this scenario, the model stability depends on previously
set up parameters associated with the equation of state of the universe. Our
results suggest that the GCG is a particularly suitable candidate for
constructing a stable MaVaN scenario.Comment: 27 pages, 9 figure
The Revival of the Unified Dark Energy-Dark Matter Model ?
We consider the generalized Chaplygin gas (GCG) proposal for unification of
dark energy and dark matter and show that it admits an unique decomposition
into dark energy and dark matter components once phantom-like dark energy is
excluded. Within this framework, we study structure formation and show that
difficulties associated to unphysical oscillations or blow-up in the matter
power spectrum can be circumvented. Furthermore, we show that the dominance of
dark energy is related to the time when energy density fluctuations start
deviating from the linear behaviour.Comment: 6 pages, 4 eps figures, Revtex4 style. New References are added. Some
typos are corrected. Conclusions remain the sam
Separating Reflection and Transmission Images in the Wild
The reflections caused by common semi-reflectors, such as glass windows, can
impact the performance of computer vision algorithms. State-of-the-art methods
can remove reflections on synthetic data and in controlled scenarios. However,
they are based on strong assumptions and do not generalize well to real-world
images. Contrary to a common misconception, real-world images are challenging
even when polarization information is used. We present a deep learning approach
to separate the reflected and the transmitted components of the recorded
irradiance, which explicitly uses the polarization properties of light. To
train it, we introduce an accurate synthetic data generation pipeline, which
simulates realistic reflections, including those generated by curved and
non-ideal surfaces, non-static scenes, and high-dynamic-range scenes.Comment: accepted at ECCV 201
Spatial Electron-hole Separation in a One Dimensional Hybrid Organic-Inorganic Lead Iodide.
The increasing efficiency of the inorganic-organic hybrid halides has revolutionised photovoltaic research. Despite this rapid progress, the significant issues of poor stability and toxicity have yet to be suitably overcome. In this article, we use Density Functional Theory to examine (Pb2I6) · (H2DPNDI) · (H2O) · (NMP), an alternative lead-based hybrid inorganic-organic solar absorber based on a photoactive organic cation. Our results demonstrate that optical properties suitable for photovoltaic applications, in addition to spatial electron-hole separation, are possible but efficient charge transport may be a limiting factor
Stereo Computation for a Single Mixture Image
This paper proposes an original problem of \emph{stereo computation from a
single mixture image}-- a challenging problem that had not been researched
before. The goal is to separate (\ie, unmix) a single mixture image into two
constitute image layers, such that the two layers form a left-right stereo
image pair, from which a valid disparity map can be recovered. This is a
severely illposed problem, from one input image one effectively aims to recover
three (\ie, left image, right image and a disparity map). In this work we give
a novel deep-learning based solution, by jointly solving the two subtasks of
image layer separation as well as stereo matching. Training our deep net is a
simple task, as it does not need to have disparity maps. Extensive experiments
demonstrate the efficacy of our method.Comment: Accepted by European Conference on Computer Vision (ECCV) 201
Wigner Function Evolution of Quantum States in Presence of Self-Kerr Interaction
A Fokker-Planck equation for the Wigner function evolution in a noisy Kerr
medium ( non-linearity) is presented. We numerically solved this
equation taking a coherent state as an initial condition. The dissipation
effects are discussed. We provide examples of quantum interference, sub-Planck
phase space structures, and Gaussian versus non-Gaussian dynamical evolution of
the state. The results also apply to the description of a nanomechanical
resonator with an intrinsic Duffing nonlinearity.Comment: 10 pages, 11 figure
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