Search results for " images"
showing 10 items of 202 documents
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…
An automatic filtering algorithm for SURF-based registration of remote sensing images
2017
International audience; The registration of remote sensing images has been often a necessary step for further analyses of images taken at different times, different viewing geometry or with different sensors. For this task there exists many approaches. This paper focuses on the feature-based category of image registration methods. Particularly, we propose an improvement of the SURF algorithm on the point matching step. Indeed, in order to achieve a correct registration, a good matching of feature point is required. However The presence of outliers lead to a fail in the registration. Therefore, in this paper, we introduce an efficient method devoted to the detection and removal of such outli…
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…
Turbidity analysis in Sicilian coastal zones by means of remote sensing images and spectroradiometric measurements
2009
Water turbidity has a wide range of variability both spatially and temporally. Rivers transport sediments to the river mouth following a seasonal behaviour and occasionally during flood events (Doxaran et al., 2006; Pribble et al., 2001). Once in the sea, sediments are spatially driven by currents, and re-suspended by waves from the bottom, changing water turbidity in the tidal and sub-tidal zones (Cloern et al., 1989; Uncles et al., 2002; Wolanski & Spagnol, 2003). Moreover human activities such as transport and dredging occasionally and locally influence turbidity magnitude and distribution (Schoellhamer, 1996). In recent years the pollution of the maritime environment suggests that only …
Graph-based minimal path tracking in the skeleton of the retinal vascular network
2012
This paper presents a semi-automatic framework for minimal path tracking in the skeleton of the retinal vascular network. The method is based on the graph structure of the vessel network. The vascular network is represented based on the skeleton of the available segmented vessels and using an undirected graph. Significant points on the skeleton are considered nodes of the graph, while the edge of the graph is represented by the vessel segment linking two neighboring nodes. The graph is represented then in the form of a connectivity matrix, using a novel method for defining vertex connectivity. Dijkstra and Floyd-Warshall algorithms are applied for detection of minimal paths within the graph…
Multi-modal Medical Image Registration by Local Affine Transformations
2018
Image registration is the process of finding the geometric transformation that, applied to the floating image, gives the registered image with the highest similarity to the reference image. Registering a pair of images involves the definition of a similarity function in terms of the parameters of the geometric transformation that allows the registration. This paper proposes to register a pair of images by iteratively maximizing the empirical mutual information through coordinate gradient descent. Hence, the registered image is obtained by applying a sequence of local affine transformations. Rather than adopting a uniformly spaced grid to select image blocks to locally register, as done by s…
Noise Filtering Using Edge-Driven Adaptive Anisotropic Diffusion
2008
This paper presents a method aimed to noise removal in MRI (Magnetic Resonance Imaging). We propose an improvement of Perona and Malik's anisotropic diffusion filter. In our schema, the diffusion equation of the filter has been modified to take into account the edges direction, This allows the filter to blur uniform areas, while it better preserves the edges. Both quantitative and qualitative evaluation is presented and the results are compared with other methods.