85 research outputs found
Beyond Geo-localization: Fine-grained Orientation of Street-view Images by Cross-view Matching with Satellite Imagery
Street-view imagery provides us with novel experiences to explore different
places remotely. Carefully calibrated street-view images (e.g. Google Street
View) can be used for different downstream tasks, e.g. navigation, map features
extraction. As personal high-quality cameras have become much more affordable
and portable, an enormous amount of crowdsourced street-view images are
uploaded to the internet, but commonly with missing or noisy sensor
information. To prepare this hidden treasure for "ready-to-use" status,
determining missing location information and camera orientation angles are two
equally important tasks. Recent methods have achieved high performance on
geo-localization of street-view images by cross-view matching with a pool of
geo-referenced satellite imagery. However, most of the existing works focus
more on geo-localization than estimating the image orientation. In this work,
we re-state the importance of finding fine-grained orientation for street-view
images, formally define the problem and provide a set of evaluation metrics to
assess the quality of the orientation estimation. We propose two methods to
improve the granularity of the orientation estimation, achieving 82.4% and
72.3% accuracy for images with estimated angle errors below 2 degrees for CVUSA
and CVACT datasets, corresponding to 34.9% and 28.2% absolute improvement
compared to previous works. Integrating fine-grained orientation estimation in
training also improves the performance on geo-localization, giving top 1 recall
95.5%/85.5% and 86.8%/80.4% for orientation known/unknown tests on the two
datasets.Comment: This paper has been accepted by ACM Multimedia 2022. The version
contains additional supplementary material
Generic two-phase coexistence in nonequilibrium systems
Gibbs' phase rule states that two-phase coexistence of a single-component
system, characterized by an n-dimensional parameter-space, may occur in an
n-1-dimensional region. For example, the two equilibrium phases of the Ising
model coexist on a line in the temperature-magnetic-field phase diagram.
Nonequilibrium systems may violate this rule and several models, where phase
coexistence occurs over a finite (n-dimensional) region of the parameter space,
have been reported. The first example of this behaviour was found in Toom's
model [Toom,Geoff,GG], that exhibits generic bistability, i.e. two-phase
coexistence over a finite region of its two-dimensional parameter space (see
Section 1). In addition to its interest as a genuine nonequilibrium property,
generic multistability, defined as a generalization of bistability, is both of
practical and theoretical relevance. In particular, it has been used recently
to argue that some complex structures appearing in nature could be truly stable
rather than metastable (with important applications in theoretical biology),
and as the theoretical basis for an error-correction method in computer science
(see [GG,Gacs] for an illuminating and pedagogical discussion of these ideas).Comment: 7 pages, 6 figures, to appear in Eur. Phys. J. B, svjour.cls and
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Enhanced absorption Hanle effect on the Fg=F->Fe=F+1 closed transitions
We analyse the Hanle effect on a closed transition. Two
configurations are examined, for linear- and circular-polarized laser
radiation, with the applied magnetic field collinear to the laser light
wavevector. We describe the peculiarities of the Hanle signal for
linearly-polarized laser excitation, characterized by narrow bright resonances
at low laser intensities. The mechanism behind this effect is identified, and
numerical solutions for the optical Bloch equations are presented for different
transitions.Comment: to be published in J. Opt. B, special issue on Quantum Coherence and
Entanglement (February 2001
Interacting Electrons on a Fluctuating String
We consider the problem of interacting electrons constrained to move on a
fluctuating one-dimensional string. An effective low-energy theory for the
electrons is derived by integrating out the string degrees of freedom to lowest
order in the inverse of the string tension and mass density, which are assumed
to be large. We obtain expressions for the tunneling density of states, the
spectral function and the optical conductivity of the system. Possible
connections with the phenomenology of the cuprate high temperature
superconductors are discussed.Comment: 14 pages, 1 figur
International Labor Migration, Economic Growth and Labor Markets - The Current State of Affairs
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