13,195 research outputs found
Tracking-Based Non-Parametric Background-Foreground Classification in a Chromaticity-Gradient Space
This work presents a novel background-foreground classification technique based on adaptive non-parametric kernel estimation in a color-gradient space of components. By combining normalized color components with their gradients, shadows are efficiently suppressed from the results, while the luminance information in the moving objects is preserved. Moreover, a fast multi-region iterative tracking strategy applied over previously detected foreground regions allows to construct a robust foreground modeling, which combined with the background model increases noticeably the quality in the detections. The proposed strategy has been applied to different kind of sequences, obtaining satisfactory results in complex situations such as those given by dynamic backgrounds, illumination changes, shadows and multiple moving objects
Real-time shot detection based on motion analysis and multiple low-level techniques
To index, search, browse and retrieve relevant material, indexes describing the video content are required. Here, a new and fast strategy which allows detecting abrupt and gradual transitions is proposed. A pixel-based analysis is applied to detect abrupt transitions and, in parallel, an edge-based analysis is used to detect gradual transitions. Both analysis are reinforced with a motion analysis in a second step, which significantly simplifies the threshold selection problem while preserving the computational requirements. The main advantage of the proposed system is its ability to work in real time and the experimental results show high recall and precision values
Neural ODEs with stochastic vector field mixtures
It was recently shown that neural ordinary differential equation models
cannot solve fundamental and seemingly straightforward tasks even with
high-capacity vector field representations. This paper introduces two other
fundamental tasks to the set that baseline methods cannot solve, and proposes
mixtures of stochastic vector fields as a model class that is capable of
solving these essential problems. Dynamic vector field selection is of critical
importance for our model, and our approach is to propagate component
uncertainty over the integration interval with a technique based on forward
filtering. We also formalise several loss functions that encourage desirable
properties on the trajectory paths, and of particular interest are those that
directly encourage fewer expected function evaluations. Experimentally, we
demonstrate that our model class is capable of capturing the natural dynamics
of human behaviour; a notoriously volatile application area. Baseline
approaches cannot adequately model this problem
Entanglement detachment in fermionic systems
This article introduces and discusses the concept of entanglement detachment.
Under some circumstances, enlarging a few couplings of a Hamiltonian can
effectively detach a (possibly disjoint) block within the ground state. This
detachment is characterized by a sharp decrease in the entanglement entropy
between block and environment, and leads to an increase of the internal
correlations between the (possibly distant) sites of the block. We provide some
examples of this detachment in free fermionic systems. The first example is an
edge-dimerized chain, where the second and penultimate hoppings are increased.
In that case, the two extreme sites constitute a block which disentangles from
the rest of the chain. Further examples are given by (a) a superlattice which
can be detached from a 1D chain, and (b) a star-graph, where the extreme sites
can be detached or not depending on the presence of an external magnetic field,
in analogy with the Aharonov-Bohm effect. We characterize these detached blocks
by their reduced matrices, specially through their entanglement spectrum and
entanglement Hamiltonian
Acorns for fattening free-range pigs (OK-Net Ecofeed Practice Abstract)
- The fattening performance is very much influenced by the age of pigs and their compensatory growth; hence, pigs should be as old as possible (≥1 year) and adapted to grazing.
- Grass is necessary as a source of protein to compensate for the low protein levels in acorns.
- The food conversion rate is 10.5 kg of whole acorns of Q. i. rotundifolia to gain 1 kg, besides the contribution of grass; to establish the stocking rate, consider that an adult evergreen oak produces ≈11 kg of acorns/year).
- Iberian pigs peel acorns to avoid the high content of tannins in the shell. However, during peeling, approxi-mately 20% of the kernel can be wasted
Kernel bandwidth estimation for moving object detection in non-stabilized cameras
The evolution of the television market is led by 3DTV technology, and this tendency can accelerate during the next years according to expert forecasts. However, 3DTV delivery by broadcast networks is not currently developed enough, and acts as a bottleneck for the complete deployment of the technology. Thus, increasing interest is dedicated to ste-reo 3DTV formats compatible with current HDTV video equipment and infrastructure, as they may greatly encourage 3D acceptance. In this paper, different subsampling schemes for HDTV compatible transmission of both progressive and interlaced stereo 3DTV are studied and compared. The frequency characteristics and preserved frequency content of each scheme are analyzed, and a simple interpolation filter is specially designed. Finally, the advantages and disadvantages of the different schemes and filters are evaluated through quality testing on several progressive and interlaced video sequences
Tipificación, caracterización y análisis-descomposición cromático de barnices incoloros, aplicados a maderas de construcción
Analizar las prestaciones de una serie de barnices, supuestamente incoloros y aplicados sobre una serie de maderas: roble, lauán blanco y tablero mdf, y utilizando técnicas de descomposición cromática, mediante el empleo de microscopio óptico de reflexión, para poder obtener un abanico gráfico de histogramas con valores numéricos de luminosidad y composición cromática, y de esta forma comprobar que los supuestos barnices que se venden como incoloros, no son totalmente incoloros sino que muestran tendencias a virar hacia alguno de los colores básicos. Paralelamente a la caracterización cualitativa de cada uno de los barnices, sobre cada especie de madera, se ensayan procedimientos que podrían usarse en el ejercicio profesional, en nivel intermedio entre el absoluto rigor científico y la opinión individual. De modo que, mientras se busca en la composición del barniz la explicación a cada comportamiento, y se evalúa su idoneidad para una madera determinada, se está ponderando también la fiabilidad, la utilidad y la rapidez, del procedimiento empleado
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