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See detailImage quality and high contrast improvements on VLT/NACO
Girard, J. H. V.; O'Neal, J.; Mawet, D. et al

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2012)

NACO is the famous and versatile diffraction limited NIR imager and spectrograph at the VLT with which ESO celebrated 10 years of Adaptive Optics. Since two years a substantial effort has been put in ... [more ▼]

NACO is the famous and versatile diffraction limited NIR imager and spectrograph at the VLT with which ESO celebrated 10 years of Adaptive Optics. Since two years a substantial effort has been put in understanding and fixing issues that directly affect the image quality and the high contrast performances of the instrument. Experiments to compensate the non-common-path aberrations and recover the highest possible Strehl ratios have been carried out successfully and a plan is hereafter described to perform such measurements regularly. The drift associated to pupil tracking since 2007 was fixed in october 2011. NACO is therefore even more suited for high contrast imaging and can be used with coronagraphic masks in the image plane. Some contrast measurements are shown and discussed. The work accomplished on NACO will serve as reference for the next generation instruments on the VLT, especially the ones working at the diffraction limit and making use of angular differential imaging (i.e. SPHERE, VISIR, and possibly ERIS). [less ▲]

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See detailImage Quality evaluation for 124I in the microPET Focus 120 scanner using the NEMA NU4-2008 phantom
Bahri, Mohamed Ali ULiege; Warnock, Geoffrey ULiege; Taleb, Dounia ULiege et al

Conference (2011, January 17)

Physical properties of iodine-124 such as its high positron energy, corresponding large positron range in tissue and the fraction of the single γ-photons emitted may have detrimental effects on the PET ... [more ▼]

Physical properties of iodine-124 such as its high positron energy, corresponding large positron range in tissue and the fraction of the single γ-photons emitted may have detrimental effects on the PET image quality. The purpose of this work was to evaluate the image quality for iodine-124 in the small animal microPET Focus 120 scanner using the NEMA NU4-2008 image quality phantom. Although the 2 ns timing window gives higher recovery coefficients and slightly lower spill-over ratios and combined with the 350-590 keV energy window gives the lowest spill-over ratio, the combination of the 350-650 keV and 6 ns windows seems to be the best compromise to obtain images with high contrast and low noise content. [less ▲]

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See detailImage quality in Coronary CT Angiography: Challenges and technical solutions.
Ghekiere, Olivier; Salgado, Rodrigo; Buls, Nico et al

in British Journal of Radiology (2017)

Multidetector CT angiography has become a widely accepted examination for non-invasive evaluation of the heart and coronary arteries. Despite its ongoing success and worldwide clinical implementation, it ... [more ▼]

Multidetector CT angiography has become a widely accepted examination for non-invasive evaluation of the heart and coronary arteries. Despite its ongoing success and worldwide clinical implementation, it remains an often-challenging procedure in which image quality, and hence diagnostic value, is determined by both technical and patient-related factors. Thorough knowledge of these factors is important to obtain high quality examinations. In this review, we discuss several key elements that may adversely affect coronary CT angiography image quality as well as potential measures that can be taken to mitigate their impact. In addition, several recent vendor-specific advances and future directions to improve image quality are discussed. [less ▲]

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See detailImage Quality, Accuracy of Attenuation and Scatter Corrections of the microPET Focus 120 Using the NEMA NU4-2008 Phantom
Bahri, Mohamed Ali ULiege; Plenevaux, Alain ULiege; Seret, Alain ULiege

Poster (2008, October)

This work aimed at evaluating the image quality and the accuracy of attenuation and scatter corrections methodologies provided with the microPET Focus 120 scanner. The protocol used here is described in ... [more ▼]

This work aimed at evaluating the image quality and the accuracy of attenuation and scatter corrections methodologies provided with the microPET Focus 120 scanner. The protocol used here is described in the forthcoming NEMA NU4-2008 document. This study included 1 h transmission experiments, with two sources (68Ge and 57Co, both one half-live old), in coincidence mode (Ge) with and without windowing, and singles mode (Ge and Co). Transmission data with Co were also collected for shorter acquisition times (515/1030/2060 s). Transmission with scatter correction, and emission with attenuation with or without scatter correction, slices were reconstructed using 2D-FBP (ramp filter). The uniformity, the recovery coefficients (RC) and the accuracy of corrections were evaluated as described in the NEMA document. We also determined the attenuation coefficient (AC) for water using the methodology applied to measure the mean pixel value for the emission slices of the uniform part of the phantom. The Co single mode measurements provided a mean AC for water closer to the theoretical value than the Ge measurements either in single or in coincidence mode even for the shortest acquisition time. Moreover, the lowest coefficients of variation per pixel of the uniform slices were measured for attenuation corrected data based on Co measurements. Also, spill-over ratio for non-emitting air and water compartments reflected a higher capability of this attenuation correction method for scatter correction. The RC measured on emission image corrected only for attenuation did not show any significant difference linked to the transmission measured methods. However, higher RC values were noted for Ge coincidence with windowing when emission data were corrected for both attenuation and scatter. Hence, Co singles transmission seems to be the most suitable method for attenuation correction on the microPET Focus 120 scanner. [less ▲]

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See detailImage Reconstruction from Strip Integrals in Computer-aided X-ray Tomography
Verly, Jacques ULiege; Bracewell, Ronald N.

Conference (1979, August)

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See detailImage reconstruction in X-ray tomography
Toye, Dominique ULiege; Fransolet, Emmanuelle; Léonard, Angélique ULiege et al

Scientific conference (2004, August)

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See detailImage sans Texte. Le vase de Leukôn
Morard, Thomas ULiege

Scientific conference (2015, November 09)

Detailed reference viewed: 16 (1 ULiège)
See detailIMAGE SATELLITAIRE - Planche IX.1 du Deuxième Atlas de Belgique
Cornélis, Bernard; Binard, Marc ULiege

Cartographic material (1996)

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See detailImage satellitaire de la Belgique – Commentaire de la planche IX-1 (en 4 langues)
Donnay, Jean-Paul ULiege; Cornélis, Bernard

in Comité Belge de Géographie (Ed.) Atlas National de Belgique (1996)

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See detailL'image scientifique : de la visualisation à la mathématisation et retour
Dondero, Maria Giulia ULiege

in Nouveaux Actes Sémiotiques (2009)

Cet article soumet à investigation les rôles des images dans la production en laboratoire et dans la littérature scientifique de l’astrophysique et de la physique théorique. D’un côté l’image en ... [more ▼]

Cet article soumet à investigation les rôles des images dans la production en laboratoire et dans la littérature scientifique de l’astrophysique et de la physique théorique. D’un côté l’image en astrophysique fonctionne en tant qu’instrument d’enregistrement des données permettant de caractériser un phénomène (régime autographique) : dans ce cas l’image transforme les traces d’un phénomène en un objet (nébuleuse, supernova, etc.), produit d’une négociation, qui sera ensuite accepté, stabilisé et institutionnalisé à l’intérieur de la discipline. De l’autre côté, l’image peut aussi devenir un instrument d’investigation, voire un terrain de travail visant la production d’autres iconographies et ainsi d’autres objets. Ce dernier fonctionnement de l’image relève du régime allographique (voir Nelson Goodman, Les langages de l’art. Pour une théorie des symboles, 1968) : dans ce cas l’image se présente comme un texte d’instructions pour la production d’autres images : elle devient un texte générateur et permet une mathématisation des données. En prenant ensuite en considération les recherches en physique théorique sur les trous noirs, notre article étudie la relation entre équations et visualisation. On étudie plus précisément la première iconographie des trous noirs proposée par l’astrophysicien Jean-Pierre Luminet en 1979. Les travaux de Luminet qu’on analyse dans notre article montrent l’effort de construction d’une iconographie d’un objet théorique ni visible ni photographiable tel les trous noirs, et la nécessité de visualiser les résultats des équations pour faire avancer les hypothèses et la connaissance de ces phénomènes. Enfin, l’image en physique théorique, produite par des équations, montre le pouvoir que la visualisation a de mettre en scène un objet pluriel, voire un certain type de trous noirs, et de devenir ainsi une image modèle mais toujours ultérieurement manipulable (diagramme). [less ▲]

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See detailL’image scientifique : Pratiques de production, visualisation et interpretation
Dondero, Maria Giulia ULiege

in Nouveaux Actes Sémiotiques (2008)

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See detailImage scientifique et énonciation du temps
Dondero, Maria Giulia ULiege

in Visible (2009), 5

Detailed reference viewed: 56 (3 ULiège)
See detailImage(s) de soi, image(s) de l’autre
Lanneau, Catherine ULiege

Conference (2010, October 16)

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See detailImage, imagination et mathématique chez Descartes et Leibniz
Bouquiaux, Laurence ULiege

in Visible (2012)

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See detailImage-based Finite Element Mesh Generation for Microstructures
D'Otreppe, Vinciane ULiege; Mengoni, Marlène ULiege; Boman, Romain ULiege et al

Conference (2011, November 14)

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See detailIMAGE-FUV multispectral observation of theta auroras.
Hubert, Benoît ULiege; Gérard, Jean-Claude ULiege; Mende, S. B. et al

Conference (2002, May 01)

The theta aurora is an auroral structure presenting a sun-aligned transpolar arc. Five different dynamic evolution of the transpolar arcs are known, some of them being symmetrical to each other, leaving ... [more ▼]

The theta aurora is an auroral structure presenting a sun-aligned transpolar arc. Five different dynamic evolution of the transpolar arcs are known, some of them being symmetrical to each other, leaving three basically different types of transpolar auroral features. The theta aurora was previously studied with in-situ particles detectors onboard polar orbiting satellites and by ultraviolet imagers. Previous imaging works focused on the electron aurora. We use the FUV imagers onboard the IMAGE spacecraft to study separately the proton and electron contributions to the transpolar arcs at the global scale. The imagers of the IMAGE-FUV experiment remotely sense the electron aurora with the WIC and SI13 imagers observing respectively the N[SUB]2[/SUB]-LBH and OI-135.6 nm emission, while the SI12 spectrographic imager measures the Doppler-shifted Lyman-ë± emission which is solely due to the auroral proton precipitation. The three different types of transpolar aurora will be analyzed using the IMAGE-FUV imagers. In particular, the relative contribution of proton and electron to the excitation of the theta aurora will be presented. [less ▲]

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See detailImage-guided failure assessment of human trabecular bone - Inverse finite element modelling for characterization of elastic properties
Zwahlen, Alexander; Christen, David; Ruffoni, Davide ULiege et al

in BIOMEDICAL ENGINEERING-BIOMEDIZINISCHE TECHNIK (2013), 58(1),

Local interpretation of micro finite element (mu FE) simulations has become important in different fields of bone biomechanics. Although on an apparent level mu FE has successfully been validated against ... [more ▼]

Local interpretation of micro finite element (mu FE) simulations has become important in different fields of bone biomechanics. Although on an apparent level mu FE has successfully been validated against experiments, local validations are sparse and limited by imaging resolution. At the tissue level heterogeneity of Young's modulus has been reported. Although non-uniform material distribution have been shown to only have a minor influence on the apparent material properties, its impact on local material behaviour is largely unknown. By combining image-guided failure assessment (IGFA) using synchrotron-based-micro-computed tomography, strain mapping and inverse mu FE modelling, we present an experimental and computational framework which will allow studying local effects of intratrabecular heterogeneity of the Young's modulus. [less ▲]

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See detailImage-guided neurosurgery ...
Verly, Jacques ULiege

Scientific conference (2004)

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See detailImage-guided surgery: the engineer’s view- point
Verly, Jacques ULiege; Vigneron, Lara M.; Kavec, Martin et al

Scientific conference (2005)

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See detailLas imágenes de España, de Franco y de la monarquía en las guías turísticas del Patrimonio Nacional (1959-1987)
Vanden Berghe, Kristine ULiege; Maddens, Bart

in Ayer. Revista de historia Contemporánea (2008), 70(2), 241-262

In this article, a discourse analysis is presented of the tourist guides published by the ‘Patrimonio Nacional’ or National Heritage, charged with the administration and preservation of the Spanish royal ... [more ▼]

In this article, a discourse analysis is presented of the tourist guides published by the ‘Patrimonio Nacional’ or National Heritage, charged with the administration and preservation of the Spanish royal sites. The analysis focuses on the guides published during the Franco era and the transition. These guides portray Spain as a nation with a deep-seated monarchist tradition, which was however usurped by the ‘decadent’ Borbon dynasty. At the same time the figure of Franco is subtly associated with the monarchy and somehow inserted in the royal imagery, both on the iconographical and textual levels. Most radically, two sites which bear no relationship with the monarchy – the Palacio de la Isla in Burgos and the Valley of the Fallen – are discursively incorporated in the royal heritage. By creating a link between Franco and the monarchist tradition, the regime attempted to enhance its legitimacy. Franco’s semi-regal status assured that his rise to power was viewed not so much as a result of a chance occurrence of circumstances but rather as a preordained succession. In the guides published during the transition, the association between Franco and the monarchy is still present, but the ideology is hidden behind a more historic discourse, a result of which Franco appears as a half forgotten historic figure. [less ▲]

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