22,480 research outputs found
Cluster-Wise Ratio Tests for Fast Camera Localization
Feature point matching for camera localization suffers from scalability
problems. Even when feature descriptors associated with 3D scene points are
locally unique, as coverage grows, similar or repeated features become
increasingly common. As a result, the standard distance ratio-test used to
identify reliable image feature points is overly restrictive and rejects many
good candidate matches. We propose a simple coarse-to-fine strategy that uses
conservative approximations to robust local ratio-tests that can be computed
efficiently using global approximate k-nearest neighbor search. We treat these
forward matches as votes in camera pose space and use them to prioritize
back-matching within candidate camera pose clusters, exploiting feature
co-visibility captured by clustering the 3D model camera pose graph. This
approach achieves state-of-the-art camera localization results on a variety of
popular benchmarks, outperforming several methods that use more complicated
data structures and that make more restrictive assumptions on camera pose. We
also carry out diagnostic analyses on a difficult test dataset containing
globally repetitive structure that suggest our approach successfully adapts to
the challenges of large-scale image localization
The IACOB project: A grid-based automatic tool for the quantitative spectroscopic analysis of O-stars
We present the IACOB grid-based automatic tool for the quantitative
spectroscopic analysis of O-stars. The tool consists of an extensive grid of
FASTWIND models, and a variety of programs implemented in IDL to handle the
observations, perform the automatic analysis, and visualize the results. The
tool provides a fast and objective way to determine the stellar parameters and
the associated uncertainties of large samples of O-type stars within a
reasonable computational time.Comment: 8 pages, 2 figures, 1 table. Proceedings of the "GREAT-ESF Stellar
Atmospheres in the Gaia Era Workshop
Real returns on government debt: a general equilibrium quantitative exploration
We extend and apply computable general equilibrium methods to the study of economies
with both aggregate uncertainty and uninsured household-specific uncertainty. In our
economies the government issues two types of assets: a small denomination, non-interest
bearing asset, which we call currency, and a large denomination, interest bearing asset,
which we call T-bills. We find that a real interest rate behavior similar to that observed
in the U.S. can be sustained as equilibrium behavior in our class of economies. We also
find that policy induced real interest rate changes that are perceived as being permanent
have significant real effects and that these effects take a few years to be fully realized
Graphene coherent states
In this paper, we will construct the coherent states for a Dirac electron in
graphene placed in a constant homogeneous magnetic field which is orthogonal to
the graphene surface. First of all, we will identify the appropriate
annihilation and creation operators. Then, we will derive the coherent states
as eigenstates of the annihilation operator, with complex eigenvalues. Several
physical quantities, as the Heisenberg uncertainty product, probability density
and mean energy value, will be as well explored.Comment: 17 pages, 32 figure
Homogenization results for chemical reactive flows through porous media
This paper deals with the homogenization of a nonlinear problem mod-elllng chemica! reactive flows through periodically perforated domains. The chemical reactions take place on the walls of the porous médium. The effective behavior of these reactive flows is described by a new elliptic boundary-value problem contalning an extra zero-order term which captures the effect of the chemical reactions
- …