234 research outputs found
Exploring Causal Relationships in Visual Object Tracking
Causal relationships can often be found in visual object tracking between the motions of the camera and that of the tracked object. This object motion may be an effect of the camera motion, e.g. an unsteady handheld camera. But it may also be the cause, e.g. the cameraman framing the object. In this paper we explore these relationships, and provide statistical tools to detect and quantify them, these are based on transfer entropy and stem from information theory. The relationships are then exploited to make predictions about the object location. The approach is shown to be an excellent measure for describing such relationships. On the VOT2013 dataset the prediction accuracy is increased by 62 % over the best non-causal predictor. We show that the location predictions are robust to camera shake and sudden motion, which is invaluable for any tracking algorithm and demonstrate this by applying causal prediction to two state-of-the-art trackers. Both of them benefit, Struck gaining a 7 % accuracy and 22 % robustness increase on the VTB1.1 benchmark, becoming the new state-of-the-art
Real-time spectroscopy of solar pp neutrinos using Nd-150
The potential real-time spectroscopy of solar pp neutrinos using Nd-150 as
target is investigated. The threshold of 196 keV would be the lowest of all
solar neutrino experiments running so far. Experimental rates and parameters
are discussed, about 580 SNU can be expected from pp-neutrinos and another 367
SNU from Be-7. Furthermore, it is investigated whether charged current
reactions might cause a new background component for future double beta decay
experiments based on a large amount of Nd-150.Comment: 9 pages, 1 figur
Positronic lithium, an electronically stable Li-e ground state
Calculations of the positron-Li system were performed using the Stochastic
Variational Method and yielded a minimum energy of -7.53208 Hartree for the L=0
ground state. Unlike previous calculations of this system, the system was found
to be stable against dissociation into the Ps + Li channel with a binding
energy of 0.00217 Hartree and is therefore electronically stable. This is the
first instance of a rigorous calculation predicting that it is possible to
combine a positron with a neutral atom and form an electronically stable bound
state.Comment: 11 pages, 2 tables. To be published in Phys.Rev.Let
Distribution and ecology of wild lettuces Lactuca serriola L. and Lactuca virosa L. in central Chile
Wild lettuces (Lactuca L.) may provide valuable genetic resources for crop breeding, but are also significant invasive weeds. Monitoring populations of these species is important, therefore, both to inform genetic resource conservation efforts as well as for non-native plant species control. We explored the occurrences, distributions, and characteristics of populations of wild Lactuca species in central Chile through field surveys in 2016 and 2017, significantly adding to the available information on these species in the region. We documented two species - prickly lettuce (Lactuca serriola L.) and opium (bitter) lettuce (Lactuca virosa L.) in 204 localities. Occurrence only of L. serriola was recorded at 166 sites, only L. virosa at 21 sites, and both at 17 sites. Prickly lettuce was observed equally in urban areas and along transport corridors outside cities. Population sizes varied from a few plants to hundreds of individuals. Opium lettuce was recorded most frequently along roads outside cities, with population sizes of several individuals to a dozen. Species succession in different elevational gradients was observed along three roads: R 60 (Los Andes – Portillo), G-27 (Cajón Maipú), and 115 (Lago Colbún – Lago del Maule). These observations indicate that: i) both allochthonous (Euroasian) wild Lactuca species occur and are able to regenerate in central Chile; ii) L. serriola forms dense populations in urbanized areas; iii) both species can expand along transport corridors to high elevations; iv) the spread of L. virosa and persistence of dense populations in elevations above 2,000 m a.s.l. prove the invasiveness of this species in extreme climates; v) both species should be monitored (and treated) both in urbanized and agricultural areas, as well as in unique local mountainous areas
From Multiview Image Curves to 3D Drawings
Reconstructing 3D scenes from multiple views has made impressive strides in
recent years, chiefly by correlating isolated feature points, intensity
patterns, or curvilinear structures. In the general setting - without
controlled acquisition, abundant texture, curves and surfaces following
specific models or limiting scene complexity - most methods produce unorganized
point clouds, meshes, or voxel representations, with some exceptions producing
unorganized clouds of 3D curve fragments. Ideally, many applications require
structured representations of curves, surfaces and their spatial relationships.
This paper presents a step in this direction by formulating an approach that
combines 2D image curves into a collection of 3D curves, with topological
connectivity between them represented as a 3D graph. This results in a 3D
drawing, which is complementary to surface representations in the same sense as
a 3D scaffold complements a tent taut over it. We evaluate our results against
truth on synthetic and real datasets.Comment: Expanded ECCV 2016 version with tweaked figures and including an
overview of the supplementary material available at
multiview-3d-drawing.sourceforge.ne
Commissioning of the vacuum system of the KATRIN Main Spectrometer
The KATRIN experiment will probe the neutrino mass by measuring the
beta-electron energy spectrum near the endpoint of tritium beta-decay. An
integral energy analysis will be performed by an electro-static spectrometer
(Main Spectrometer), an ultra-high vacuum vessel with a length of 23.2 m, a
volume of 1240 m^3, and a complex inner electrode system with about 120000
individual parts. The strong magnetic field that guides the beta-electrons is
provided by super-conducting solenoids at both ends of the spectrometer. Its
influence on turbo-molecular pumps and vacuum gauges had to be considered. A
system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter
strips has been deployed and was tested during the commissioning of the
spectrometer. In this paper the configuration, the commissioning with bake-out
at 300{\deg}C, and the performance of this system are presented in detail. The
vacuum system has to maintain a pressure in the 10^{-11} mbar range. It is
demonstrated that the performance of the system is already close to these
stringent functional requirements for the KATRIN experiment, which will start
at the end of 2016.Comment: submitted for publication in JINST, 39 pages, 15 figure
- …