500 research outputs found
Live User-guided Intrinsic Video For Static Scenes
We present a novel real-time approach for user-guided intrinsic decomposition of static scenes captured by an RGB-D sensor. In the first step, we acquire a three-dimensional representation of the scene using a dense volumetric reconstruction framework. The obtained reconstruction serves as a proxy to densely fuse reflectance estimates and to store user-provided constraints in three-dimensional space. User constraints, in the form of constant shading and reflectance strokes, can be placed directly on the real-world geometry using an intuitive touch-based interaction metaphor, or using interactive mouse strokes. Fusing the decomposition results and constraints in three-dimensional space allows for robust propagation of this information to novel views by re-projection.We leverage this information to improve on the decomposition quality of existing intrinsic video decomposition techniques by further constraining the ill-posed decomposition problem. In addition to improved decomposition quality, we show a variety of live augmented reality applications such as recoloring of objects, relighting of scenes and editing of material appearance
Development of Combined Opto-Acoustical Sensor Modules
The faint fluxes of cosmic neutrinos expected at very high energies require
large instrumented detector volumes. The necessary volumes in combination with
a sufficient shielding against background constitute forbidding and complex
environments (e.g. the deep sea) as sites for neutrino telescopes. To withstand
these environments and to assure the data quality, the sensors have to be
reliable and their operation has to be as simple as possible. A compact sensor
module design including all necessary components for data acquisition and
module calibration would simplify the detector mechanics and ensures the long
term operability of the detector. The compact design discussed here combines
optical and acoustical sensors inside one module, therefore reducing
electronics and additional external instruments for calibration purposes. In
this design the acoustical sensor is primary used for acoustic positioning of
the module. The module may also be used for acoustic particle detection and
marine science if an appropriate acoustical sensor is chosen.
First tests of this design are promising concerning the task of calibration.
To expand the field of application also towards acoustic particle detection
further improvements concerning electromagnetic shielding and adaptation of the
single components are necessary.Comment: 4 pages, 2 figures, ARENA2010 proceeding
Reconstruction methods for acoustic particle detection in the deep sea using clusters of hydrophones
This article focuses on techniques for acoustic noise reduction, signal
filters and source reconstruction. For noise reduction, bandpass filters and
cross correlations are found to be efficient and fast ways to improve the
signal to noise ratio and identify a possible neutrino-induced acoustic signal.
The reconstruction of the position of an acoustic point source in the sea is
performed by using small-volume clusters of hydrophones (about 1 cubic meter)
for direction reconstruction by a beamforming algorithm. The directional
information from a number of such clusters allows for position reconstruction.
The algorithms for data filtering, direction and position reconstruction are
explained and demonstrated using simulated data.Comment: 7 pages, 13 figure
EgoCap: Egocentric Marker-less Motion Capture with Two Fisheye Cameras (Extended Abstract)
Marker-based and marker-less optical skeletal motion-capture methods use an outside-in arrangement of cameras placed around a scene, with viewpoints converging on the center. They often create discomfort by possibly needed marker suits, and their recording volume is severely restricted and often constrained to indoor scenes with controlled backgrounds. We therefore propose a new method for real-time, marker-less and egocentric motion capture which estimates the full-body skeleton pose from a lightweight stereo pair of fisheye cameras that are attached to a helmet or virtual-reality headset. It combines the strength of a new generative pose estimation framework for fisheye views with a ConvNet-based body-part detector trained on a new automatically annotated and augmented dataset. Our inside-in method captures full-body motion in general indoor and outdoor scenes, and also crowded scenes
Position reconstruction of acoustic sources with the AMADEUS Detector
This article focuses on techniques for position reconstruction of acoustic
point sources with the AMADEUS setup consisting of 36 acoustic sensors in the
Mediterranean Sea. The direction reconstruction of an acoustic point source
utilizes the information of the 6 small-volume hydrophone clusters of AMADEUS
individually. Source position reconstruction is then done by combining the
directional information of each cluster. The algorithms for direction and
position reconstruction are explained and demonstrated using data taken in the
deep sea.Comment: 4 pages, 7 figures, to appear in the proceedings of the 3rd
International Workshop on the Acoustic and Radio EeV Neutrino detection
Activities, Rome, Ital
A Versatile Scene Model with Differentiable Visibility Applied to Generative Pose Estimation
Generative reconstruction methods compute the 3D configuration (such as pose and/or geometry) of a shape by optimizing the overlap of the projected 3D shape model with images. Proper handling of occlusions is a big challenge, since the visibility function that indicates if a surface point is seen from a camera can often not be formulated in closed form, and is in general discrete and non-differentiable at occlusion boundaries. We present a new scene representation that enables an analytically differentiable closed-form formulation of surface visibility. In contrast to previous methods, this yields smooth, analytically differentiable, and efficient to optimize pose similarity energies with rigorous occlusion handling, fewer local minima, and experimentally verified improved convergence of numerical optimization. The underlying idea is a new image formation model that represents opaque objects by a translucent medium with a smooth Gaussian density distribution which turns visibility into a smooth phenomenon. We demonstrate the advantages of our versatile scene model in several generative pose estimation problems, namely marker-less multi-object pose estimation, marker-less human motion capture with few cameras, and image-based 3D geometry estimation
Multi-vessel stenting during primary percutaneous coronary intervention for acute myocardial infarction. A single-center experience
BACKGROUND: Recanalization of the culprit lesion is the main goal of primary angioplasty for acute ST-segment elevation myocardial infarction (STEMI). Patients presenting with acute myocardial infarction and multivessel disease are, therefore, usually subjected to staged procedures, with the primary percutaneous coronary intervention (PCI) confined to recanalization of the infarct-related artery (IRA). Theoretically at least, early relief of stenoses of non-infarct-related arteries could promote collateral circulation, which could help to limit the infarct size. However, the safety and feasibility of such an approach has not been adequately established. METHODS: In this single-center prospective study we examined 73 consecutive patients who had an acute STEMI and at least one or more lesions > or = 70% in a major epicardial vessel other than the infarct-related artery. In the first 28 patients, forming the multi-vessel (MV) PCI group, all lesions were treated during the primary procedure. In the following 45 patients, forming the culprit-only (CO) PCI group, only the culprit lesion was treated during the initial procedure, followed by either planned-staged or ischemia-driven revascularization of the non-culprit lesions. Fluoroscopy time and contrast dye amount were compared between both groups, and patients were followed up for one year for major adverse cardiac events (MACE) and other significant clinical events. RESULTS: The two groups were well balanced in terms of clinical characteristics, number of diseased vessels and angiographic characteristics of the culprit lesion. In the MV-PCI group, 2.51 lesions per patient were treated using 2.96 +/- 1.34 stents (1.00 lesions and 1.76 +/- 1.17 stents in the CO-PCI group, both p < 0.001). The fluoroscopy time increased from 10.3 (7.2-16.9) min in the CO-PCI group to 12.5 (8.5-19.3) min in the MV-PCI group (p = 0.22), and the amount of contrast used from 200 (180-250) ml to 250 (200-300) ml, respectively (p = 0.16). Peak CK and CK-MB were significantly lower in patients of the MV-PCI group (843 +/- 845 and 135 +/- 125 vs 1652 +/- 1550 and 207 +/- 155 U/l, p < 0.001 and 0.01, respectively). Similar rates of major adverse cardiac events at one year were observed in the two groups (24% and 28% in multi-vessel and culprit treatment groups, p = 0.73). The incidence of new revascularization in both infarct- and non-infarct-related arteries was also similar (24% and 28%, respectively, p = 0.73). CONCLUSION: We may state from this limited experience that a multi-vessel stenting approach for patients with acute STEMI and multi-vessel disease is feasible and probably safe during routine clinical practice. Our data suggest that this approach may help to limit the infarct size. However, larger studies, perhaps using drug-eluting stents, are still needed to further evaluate the safety and efficiency of this procedure, and whether it is associated with a lower need of subsequent revascularization and lower costs
Involvement of formyl peptide receptors in the stimulatory effect of crotoxin on macrophages co-cultivated with tumour cells
Crotoxin (CTX) is the main neurotoxic component of Crotalus durissus terrificus snake venom. It inhibits tumour growth and modulates the function of macrophages, which are essential cells in the tumour microenvironment. the present study investigated the effect of CTX on the secretory activity of monocultured macrophages and macrophages co-cultivated with LLC-WRC 256 cells. the effect of the macrophage secretory activities on tumour cell proliferation was also evaluated. Macrophages pre-treated with CTX (0.3 mu g/mL) for 2 h were co-cultivated with LLC-WRC 256 cells, and the secretory activity of the macrophages was determined after 12, 24 and 48 h. the co-cultivation of CTX-treated macrophages with the tumour cells caused a 20% reduction in tumour cell proliferation. the production of both H2O2 and NO was increased by 41% and 29% after 24 or 48 h of co-cultivation, respectively, compared to the values for the co-cultures of macrophages of control. the level of secreted IL-1 beta increased by 3.7- and 3.2-fold after 12 h and 24 h of co-cultivation, respectively. Moreover, an increased level of LXA(4) (25%) was observed after 24 h of co-cultivation, and a 2.3- and 2.1-fold increased level of 15-epi-LXA(4) was observed after 24 h and 48 h, respectively. Boc-2, a selective antagonist of formyl peptide receptors, blocked both the stimulatory effect of CTX on the macrophage secretory activity and the inhibitory effect of these cells on tumour cell proliferation. Taken together, these results indicate that CTX enhanced the secretory activity of macrophages, which may contribute to the antitumour activity of these cells, and that activation of formyl peptide receptors appears to play a major role in this effect. (C) 2013 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq)PAPInstituto Nacional de Ciencia e Tecnologia em ToxinasButantan Inst, Lab Pathophysiol, BR-05503900 São Paulo, BrazilUniversidade Federal de São Paulo, Lab Inflammat & Vasc Pharmacol, BR-09913030 Diadema, SP, BrazilUniv São Paulo, Fac Med, BR-01246000 São Paulo, BrazilUniv São Paulo, Inst Biomed Sci, Dept Anat, BR-05508900 São Paulo, BrazilUniv São Paulo, Inst Biomed Sci, Dept Physiol & Biophys, BR-05508900 São Paulo, BrazilButantan Inst, Special Lab Pain & Signaling, BR-05503900 São Paulo, BrazilUniversidade Federal de São Paulo, Lab Inflammat & Vasc Pharmacol, BR-09913030 Diadema, SP, BrazilFAPESP: 09/52330-9Instituto Nacional de Ciencia e Tecnologia em Toxinas: INCTTOX 2008/57898-0Web of Scienc
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