104 research outputs found

    The role of ephemeris and GPSs distribution in high resolution satellite images modeling.

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    The geometric resolution of the images coming from the new generation satellites is almost competitive with that found in the traditional aerial photograms. The aim of this work is to define the role of satellite ephemerides and to optimise the number andvdistribution of Ground Control Points (GCPs) for the image registration. A zone of the Campania region in Italy has been used as a test area: it is characterized by a mountainous area without constructions and by flat land areas densely inhabited. The images that have been used relate to different epochs and different satellites such as Spot5, Ikonos2 and QuickBird. Spot5 images have also been used to generate automatic Digital Elevation Models (DEMs). The assessment of DEM precision has been carried out by comparison with raster DEMs from cartography. The GCPs coordinates have been obtained from a GPS network made up of almost hundred and some of them are used as Check Points (CPs). Different tests have been performed, either varying the number of GCPs or hypothesizing the presence or absence of satellite ephemeris. Some numerical evaluations confirm that the use of the satellite ephemeris greatly reduces the amount of residuals on the CPs; in the case of Spot5 images this improvement becomes even more evident

    Procedimento per la generazione e l'analisi di segnali di elettrochemiluminescenza e relativo sistema

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    La presente invenzione si riferisce a un procedimento per la generazione e l‟analisi di segnali di elettrochemiluminescenza, che comprende le operazioni di generare uno stimolo in una cella elettrochimica comprendente un elettrodo di lavoro comprendente nanotubi di carbonio in contatto con una soluzione da misurare, cui è applicato detto stimolo, e rilevare e analizzare un segnale di elettrochemiluminescenza rappresentativo di radiazione di elettrochemiluminescenza emessa da detta soluzione in risposta a detto stimol

    The use of chest magnetic resonance imaging in interstitial lung disease: A systematic review

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    Thin-slices multi-detector computed tomography (MDCT) plays a key role in the differential diagnosis of interstitial lung disease (ILD). However, thin-slices MDCT has a limited ability to detect active inflammation, which is an important target of newly developed ILD drug therapy. Magnetic resonance imaging (MRI), thanks to its multi-parameter capability, provides better tissue characterisation than thin-slices MDCT. Our aim was to summarise the current status of MRI applications in ILD and to propose an ILD-MRI protocol. A systematic literature search was conducted for relevant studies on chest MRI in patients with ILD. We retrieved 1246 papers of which 55 original papers were selected for the review. We identified 24 studies comparing image quality of thin-slices MDCT and MRI using several MRI sequences. These studies described new MRI sequences to assess ILD parenchymal abnormalities, such as honeycombing, reticulation and ground-glass opacity. Thin-slices MDCT remains superior to MRI for morphological imaging. However, recent studies with ultra-short echo-time MRI showed image quality comparable to thin-slices MDCT. Several studies demonstrated the added value of chest MRI by using functional imaging, especially to detect and quantify inflammatory changes. We concluded that chest MRI could play a role in ILD patients to differentiate inflammatory and fibrotic changes and to assess efficacy of new ILD drugs

    Spectroscopic response and charge transport properties of CdZnTe detectors grown by the vertical Bridgman technique

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    In this work, we present the results of spectroscopic investigations on CdZnTe (CZT) detectors grown by the boron oxide encapsulated vertical Bridgman technique (IMEM-CNR, Parma, Italy). The detectors, with different thicknesses (1 and 2.5 mm), are characterized by the same electrode layout (gold electroless contacts): the anode is a central electrode (2 × 2 mm 2 ) surrounded by a guard-ring electrode, while the cathode is a planar electrode covering the detector surface (4.1 × 4.1 mm 2 ). The results of electrical investigations point out the low leakage currents of these detectors even at high bias voltages: 38 nA/cm 2 (T = 25°C) at 10000 V/cm. The time-stability and the spectroscopic response of the detectors, at different temperatures and fluxes, were investigated. 241 Am spectra were measured up to 1 Mcps. The detectors were compared with the traveling heater method (THM) CZT grown detectors (Redlen), fabricated with the same electrode layout. These activities are in the framework of an Italian research project on the development of energy-resolved photon counting (ERPC) systems for high flux energy-resolved X-ray imaging

    The use of chest magnetic resonance imaging in interstitial lung disease: a systematic review

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    Thin-slices multi-detector computed tomography (MDCT) plays a key role in the differential diagnosis of interstitial lung disease (ILD). However, thin-slices MDCT has a limited ability to detect active inflammation, which is an important target of newly developed ILD drug therapy. Magnetic resonance imaging (MRI), thanks to its multi-parameter capability, provides better tissue characterisation than thin-slices MDCT.Our aim was to summarise the current status of MRI applications in ILD and to propose an ILD-MRI protocol. A systematic literature search was conducted for relevant studies on chest MRI in patients with ILD.We retrieved 1246 papers of which 55 original papers were selected for the review. We identified 24 studies comparing image quality of thin-slices MDCT and MRI using several MRI sequences. These studies described new MRI sequences to assess ILD parenchymal abnormalities, such as honeycombing, reticulation and ground-glass opacity. Thin-slices MDCT remains superior to MRI for morphological imaging. However, recent studies with ultra-short echo-time MRI showed image quality comparable to thin-slices MDCT. Several studies demonstrated the added value of chest MRI by using functional imaging, especially to detect and quantify inflammatory changes.We concluded that chest MRI could play a role in ILD patients to differentiate inflammatory and fibrotic changes and to assess efficacy of new ILD drugs

    NON-CURRENT EPHEMERIS FOR APPROXIMATED CALCULATIONS

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    Some methods providing the opportunity to obtain a star's altazimuth coordinates from non-current right ascension and declination are discussed

    Stazione astronomica con teodolite elettronico: metodologie operative e di calcolo

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    Viene testato un teodolite elettronico Wild T2000 per il rilievo di dati astronomici finalizzati al computo della deviazione della verticale. L'avvento degli strumenti elettronici ha rivoluzionato non poco le operazioni di rilievo e di calcolo ponendo alcuni interrogativi sulla gestione della enorme mole di dati che vengono acquisiti in tempi prima impensabili. Il calcolo delle coordinate astronomiche è stato effettuato in doppio modo utilizzando le classiche metodologie delle rette d'altezza e rette d'azimut

    DSM da stereocoppie SPOT

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    This paper presents some of the results obtained in the field of the automatic extraction of digital surface models (DSM) using two satellite stereo-pairs images, SPOT 4 and SPOT 5, elaborated by means of a commercial software . With reference to the first stereo pair the comparison with a reference DTM is according to the standards; relatively to the second one results are not acceptable for the bad geometric configuration and for the presence of remarkable radiometric differences in the two images
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