53 research outputs found

    Efficient Online Surface Correction for Real-time Large-Scale 3D Reconstruction

    Full text link
    State-of-the-art methods for large-scale 3D reconstruction from RGB-D sensors usually reduce drift in camera tracking by globally optimizing the estimated camera poses in real-time without simultaneously updating the reconstructed surface on pose changes. We propose an efficient on-the-fly surface correction method for globally consistent dense 3D reconstruction of large-scale scenes. Our approach uses a dense Visual RGB-D SLAM system that estimates the camera motion in real-time on a CPU and refines it in a global pose graph optimization. Consecutive RGB-D frames are locally fused into keyframes, which are incorporated into a sparse voxel hashed Signed Distance Field (SDF) on the GPU. On pose graph updates, the SDF volume is corrected on-the-fly using a novel keyframe re-integration strategy with reduced GPU-host streaming. We demonstrate in an extensive quantitative evaluation that our method is up to 93% more runtime efficient compared to the state-of-the-art and requires significantly less memory, with only negligible loss of surface quality. Overall, our system requires only a single GPU and allows for real-time surface correction of large environments.Comment: British Machine Vision Conference (BMVC), London, September 201

    Detection of delirium by family members in the intensive care unit: Translation, Cross-Cultural adaptation and validation of the Family Confusion Assessment Method for the German-Speaking area

    Full text link
    Aim: The aim of this study was the translation, cross-cultural adaptation and validation of the Family Confusion Assessment Method in critically ill patients. Background: Delirium is a frequently unrecognized disorder in critically ill patients. Visiting family members might be the first to notice subtle changes in a patient's cognition and behaviour. The Family Confusion Assessment Method was developed to detect delirium by family members, but has not been available for the German-speaking area yet. Design: A prospective validation study was conducted between January 2020 and October 2020. Methods: The Family Confusion Assessment Method was translated into German according to the Principles of Good Practice for the Translation and Cultural Adaptation Process for Patient-Reported Outcomes. Subsequently, we compared the Family Confusion Assessment Method with the Confusion Assessment Method for the Intensive Care Unit in critically ill patients and their family members in a medical intensive care unit in Germany. Results: We included 50 dyads of critically ill patients and their family members. The prevalence of delirium measured by Confusion Assessment Method for the Intensive Care Unit was 44%. Cohen's kappa coefficient was 0.84. The German Family Confusion Assessment Method had a high sensitivity of 95.5% and specificity of 89.3%. The positive predictive value and negative predictive value were 87.5% and 96.2% respectively. Conclusions: These findings suggest that the German Family Confusion Assessment Method is an accurate assessment tool for delirium detection in the intensive care unit by family members. Furthermore, the results indicate that family members may identify delirium by the Family Confusion Assessment Method without prior training. Impact: Collaborating medical staff with patients' family members to detect delirium in the intensive care unit may lead to early recognition of delirium. Keywords: Family Confusion Assessment Method; delirium; family members; intensive care unit; nurses; validation study

    Physical studies of Centaurs and Trans-Neptunian Objects with the Atacama Large Millimeter Array

    Full text link
    Once completed, the Atacama Large Millimeter Array (ALMA) will be the most powerful (sub)millimeter interferometer in terms of sensitivity, spatial resolution and imaging. This paper presents the capabilities of ALMA applied to the observation of Centaurs and Trans-Neptunian Objects, and their possible output in terms of physical properties. Realistic simulations were performed to explore the performances of the different frequency bands and array configurations, and several projects are detailed along with their feasibility, their limitations and their possible targets. Determination of diameters and albedos via the radiometric method appears to be possible on ~500 objects, while sampling of the thermal lightcurve to derive the bodies' ellipticity could be performed at least 30 bodies that display a significant optical lightcurve. On a limited number of objects, the spatial resolution allows for direct measurement of the size or even surface mapping with a resolution down to 13 milliarcseconds. Finally, ALMA could separate members of multiple systems with a separation power comparable to that of the HST. The overall performance of ALMA will make it an invaluable instrument to explore the outer solar system, complementary to space-based telescopes and spacecrafts.Comment: Accepted for publication in Icarus (23 pages, 7 figures

    Hierarchical and fractal structuring in polymer processing

    No full text
    \u3cp\u3eThe potential of structuring thermoplastic polymers by convection only, using a combination of static mixer elements, which easily produce stratified structures with thousands of layers, and the black box concept that serves to elegantly combine materials in standard co-extrusion technology is investigated. The aim is to obtain an alternative for routes that try to structure organic matter such as polymers down to submicrometer levels, usually via self-organization based on phase separation. Structure is characterized by its complexity, here defined by the level of hierarchy. Horizontal stratification, parallel to the surface, is level 0. Vertical stratification connected to horizontal surface layers, is level 1. A series of horizontal stratifications in distinct places vertically connected to the surface layers is level 2. Higher levels of hierarchy finally result in dendritic structures that are fractal. Applications of complex structures with a huge interface and guaranteed cocontinuity throughout the whole cross section of the products are found in, for example, membranes for fuel cells and gas separators, and in miniaturizing electronic and optical devices such as photovoltaic cells. (Figure presented.).\u3c/p\u3

    Hierarchical and fractal structuring in polymer processing

    No full text
    The potential of structuring thermoplastic polymers by convection only, using a combination of static mixer elements, which easily produce stratified structures with thousands of layers, and the black box concept that serves to elegantly combine materials in standard co-extrusion technology is investigated. The aim is to obtain an alternative for routes that try to structure organic matter such as polymers down to submicrometer levels, usually via self-organization based on phase separation. Structure is characterized by its complexity, here defined by the level of hierarchy. Horizontal stratification, parallel to the surface, is level 0. Vertical stratification connected to horizontal surface layers, is level 1. A series of horizontal stratifications in distinct places vertically connected to the surface layers is level 2. Higher levels of hierarchy finally result in dendritic structures that are fractal. Applications of complex structures with a huge interface and guaranteed cocontinuity throughout the whole cross section of the products are found in, for example, membranes for fuel cells and gas separators, and in miniaturizing electronic and optical devices such as photovoltaic cells. (Figure presented.)

    Analyse des sols et réponse de quelques céréales tropicales sèches à la fumure potassique

    Full text link
    Up to one third of children with epilepsy develop drug-resistant epilepsy, while in selected cases surgi- cal treatment plays an important role. In this review we describe the indications for temporal lobe surgery and corpus callosotomy, the technical aspects of these surgeries, and morbidity and outcome following these procedures

    High-Performance Polyethylene Fibers “Al Dente”: Improved Gel-Spinning of Ultrahigh Molecular Weight Polyethylene Using Vegetable Oils

    No full text
    We demonstrate that the major drawbacks of so-called gel spinning and solid-state processing of “virgin”, i.e. never molten or fully dissolved, ultrahigh molecular weight polyethylene (UHMW PE) to produce ultrahigh modulus and ultrahigh strength fibers and films, which are the unfavorably low polymer concentrations in highly flammable solvents typically employed in the former process and low production rates in the latter, can be largely avoided by employing relatively poor—as opposed to good—solvents, including, among others, fatty acids and natural oils omnipresent in, for example, fruits, nuts, and seeds, which have additional major recovery and environmental advantages.ISSN:1520-5835ISSN:0024-929
    corecore