Search results for " Images."
showing 10 items of 193 documents
The use of very high-resolution images for mapping of Posidonia oceanica reef
2020
Posidonia oceanica is an endemic Mediterranean seagrass that forms wide and dense meadows from the surface up to about 40 m depth. P. oceanica can develop on matte, a typical terraced structure built up by itself, consisting of intertwined rhizomes, roots and sediment, which may allow shoots to reach the sea surface, where may form typical reefs (récif barrière) considered “natural monuments”. These structures have received increasing attention for the potential ecosystem services they provide in protecting the coasts from erosion, forming new habitats (coastal lagoons) and contributing to carbon sink. P. oceanica reefs are particularly exposed to the expected increase in temperature and to…
Teacher Agency and Futures Thinking
2022
Problems encountered in top-down school reforms have repeatedly highlighted the significance of teachers’ agency in educational change. At the same time, temporality has been identified as a key element in teachers’ agency, with teachers’ beliefs about the future and experiences of the past shaping their agentic orientations. However, research on teachers’ future orientations is typically limited to short-term trajectories, as opposed to long-term visions of education. To address this, we draw on a futures studies perspective to give more explicit attention to teachers’ long-term visions of their work. We argue that the method of future narratives, already well…
QR-Factorization Algorithm for Computed Tomography (CT): Comparison With FDK and Conjugate Gradient (CG) Algorithms
2018
[EN] Even though QR-factorization of the system matrix for tomographic devices has been already used for medical imaging, to date, no satisfactory solution has been found for solving large linear systems, such as those used in computed tomography (CT) (in the order of 106 equations). In CT, the Feldkamp, Davis, and Kress back projection algorithm (FDK) and iterative methods like conjugate gradient (CG) are the standard methods used for image reconstruction. As the image reconstruction problem can be modeled by a large linear system of equations, QR-factorization of the system matrix could be used to solve this system. Current advances in computer science enable the use of direct methods for…
Comparison of stereo vision techniques for cloud-top height retrieval
2007
This paper presents an ongoing study for the estimation of the cloud-top height by using only geometrical methods. In agreement with some recent studies showing that it is possible to achieve reliable height estimations not only with the classical methods based on radiative transfer, this article includes a comparison of performances of a selected set of vision algorithms devoted to extract dense disparity maps or motion fields from Infra Red stereo image pairs. This collection includes both area-based techniques and an optical flow-based method and the comparison is accomplished by using a set of cloudy scenes selected from the Along-Track Scanning Radiometer (ATSR2) database. The first gr…
Selection of optimal narrowband multispectral images for face recognition
2015
Face recognition systems based on ’conventional’ images have reached a significant level of maturity with some practical successes. However, their performance may degrade under poor and/or changing illumination. Multispectral imagery represents a viable alternative to conventional imaging in the search for a robust and practical identification system. Multi- spectral imaging (MI) can be defined as a ’collection of several monochrome images of the same scene, each of them taken with additional receptors sensitive to other frequencies of the visible light or to frequencies beyond the visible light like the infrared region of electro- magnetic continuum. Each image is referred to as a band or …
AYLAN E COLONIA. DALLA GUERRA AI MIGRANTI AL RESPINGIMENTO DEI REFUGEES
2017
This contribution aims to shed light on the specific mechanism of migrant categorization implemented by the so-called «Hotspot approach», which was launched by the EU Agenda on Migration in May 2015. This approach is here envisaged as a response to the current changes in the composition of migration towards Europe. Provisions contained in EU and Italian policy documents are compared with concrete practices enacted on the ground by investigating two case studies: the initial opening of the Hotspot at Milo, in Trapani, and the first months of functioning of the Hotspot on Lampedusa. The empirical research covers the period between the last months of 2015 and the beginning of 2016. The short-t…
Histoire de l'art et anthropologie, 3. Exégèse textuelle, exégèse visuelle. Autour du processus de la chose, " res ", dans le haut Moyen Âge
2009
À l'intersection de l'exégèse biblique et de l'étude iconographique des formes et des figures dans les codex d'époque carolingienne, nous soulignons la rencontre, au premier regard, plutôt imprévue, mais nullement improbable, dans le champ de l'analogie, entre les allégories pensées par les théologiens, tels Bède le Vénérable (673 ?-735), Ambroise Autpert († 784), Raban Maur (v. 783-856) et Haymon d'Auxerre (fl. 840-860), autour des livres bibliques de l'Exode (28, 15-21), d'Ézéchiel (28, 13) et de l'Apocalypse (21, 18-21), et les matières précieuses, les gemmes, ainsi que les autres composantes utilisées dans les reliures sculptées en ivoire, autour des riches manuscrits réalisés pour le s…
Application unit for the administration of contrast gases for pulmonary magnetic resonance imaging: optimization of ventilation distribution for3He-M…
2014
Purpose MRI of lung airspaces using gases with MR-active nuclei (3He, 129Xe, and 19F) is an important area of research in pulmonary imaging. The volume-controlled administration of gas mixtures is important for obtaining quantitative information from MR images. State-of-the-art gas administration using plastic bags (PBs) does not allow for a precise determination of both the volume and timing of a 3He bolus. Methods A novel application unit (AU) was built according to the requirements of the German medical devices law. Integrated spirometers enable the monitoring of the inhaled gas flow. The device is particularly suited for hyperpolarized (HP) gases (e.g., storage and administration with m…
Semi-automatic registration of retinal images based on line matching approach
2013
Accurate retinal image registration is essential to track the evolution of eye-related diseases. We propose a semiautomatic method based on features relying upon retinal graphs for temporal registration of retinal images. The features represent straight lines connecting vascular landmarks on the retina vascular tree: bifurcations, branchings, crossings, end points. In the built retinal graph, one straight line between two vascular landmarks indicates that they are connected by a vascular segment in the original retinal image. The locations of the landmarks are manually extracted to avoid the information loss due to errors in a retinal vessels segmentation algorithms. A straight line model i…
Lost in space? Using geo-narratives to interpret land use changes in a rural landscape of inner Sicily
2021
Intercropping landscapes characterised by the presence of certain plant features (i.e. old-century olive trees) are usually considered traditional landscapes, extremely important for their biocultural heritage. Olive agroforestry systems were widespread in the past throughout Sicily. Recent evolution processes involving intensification have switched to olive grove monocultures. Here we present ongoing work on the application of geo-narratives to interpret transformation dynamics of land use practices in a rural landscape of inner Sicily. Based on the assumption that spatial patterns are the expression of transformation processes, where the spatial variation of human activities is a signific…