Search results for "Three-Dimensional"
showing 10 items of 370 documents
Comparison of basis functions for 3D PET reconstruction using a Monte Carlo system matrix.
2012
In emission tomography, iterative statistical methods are accepted as the reconstruction algorithms that achieve the best image quality. The accuracy of these methods relies partly on the quality of the system response matrix (SRM) that characterizes the scanner. The more physical phenomena included in the SRM, the higher the SRM quality, and therefore higher image quality is obtained from the reconstruction process. High-resolution small animal scanners contain as many as 103?104 small crystal pairs, while the field of view (FOV) is divided into hundreds of thousands of small voxels. These two characteristics have a significant impact on the number of elements to be calculated in the SRM. …
Luoghi urbani scomparsi e architetture mai realizzate nella riconfigurazione 3D del Rione Conceria di Palermo
2018
L'oggetto di studio è lo scomparso Rione Conceria all'interno del Centro Storico di Palermo. È una vasta area urbana, che si estende lungo la Via Maqueda, Via Roma, Corso Vittorio Emanuele e Via Bandiera, che storicamente faceva parte di un unico sistema urbano che cuciva il mercato del Capo con il Mercato della Vucciria. Le operazioni urbanistiche del secolo scorso (il taglio di via Roma, il il progetto di riorganizzazione dell'intero rione, la costruzione della Galleria delle Vittorie) hanno cancellato quasi definitivamente sia le sue presenza architettoniche che l'impianto del suo tessuto viario. The object of study is the disappeared Rione Conceria inside the Historical Center of Palerm…
Immagine urbana e qualità dello spazio nel rilievo tridimensionale di due borgate storiche palermitane
2014
Lo sviluppo dei software di rappresentazione digitale ha comportato una significativa evo- luzione dei modelli rappresentativi, aprendo contemporaneamente la strada a nuove que- stioni di natura non soltanto operativa, ma anche sostanziale. L’assenza di scala di riduzione, la tridimensionalità in “real time”, l’immersività e l’interattività dello spazio virtuale sono infatti ben più di semplici novità strumentali: si pongono come nuovi codici, introducono una visibilità simultanea e onnicomprensiva, definiscono il modello che si viene a elaborare come un “alter” dello spazio indagato, autonomo e parallelo alla realtà stessa, ben più insomma del ruolo di “model- lo” del reale al quale la rap…
Vascular Endothelial Growth Factor-Releasing Microspheres Based on Poly(ε-Caprolactone-PEG-ε-Caprolactone)-b-Poly(L-Lactide) Multiblock Copolymers In…
2020
Pancreatic islet transplantation is a promising advanced therapy that has been used to treat patients suffering from diabetes type 1. Traditionally, pancreatic islets are infused via the portal vein, which is subsequently intended to engraft in the liver. Severe immunosuppressive treatments are necessary, however, to prevent rejection of the transplanted islets. Novel approaches therefore have focused on encapsulation of the islets in biomaterial implants which can protect the islets and offer an organ-like environment. Vascularization of the device’s surface is a prerequisite for the survival and proper func- tioning of transplanted pancreatic islets. We are pursuing a prevascularization s…
Augmented Reality of the Middle Ear Combining Otoendoscopy and Temporal Bone Computed Tomography
2018
International audience; HYPOTHESIS:Augmented reality (AR) may enhance otologic procedures by providing sub-millimetric accuracy and allowing the unification of information in a single screen.BACKGROUND:Several issues related to otologic procedures can be addressed through an AR system by providing sub-millimetric precision, supplying a global view of the middle ear cleft, and advantageously unifying the information in a single screen. The AR system is obtained by combining otoendoscopy with temporal bone computer tomography (CT).METHODS:Four human temporal bone specimens were explored by high-resolution CT-scan and dynamic otoendoscopy with video recordings. The initialization of the system…
Coxsackievirus B3-Induced Cellular Protrusions: Structural Characteristics and Functional Competence▿†
2011
ABSTRACT Virus-induced alterations in cell morphology play important roles in the viral life cycle. To examine the intracellular events of coxsackievirus B3 (CVB3) infection, green monkey kidney (GMK) cells were either inoculated with the virus or transfected with the viral RNA. Various microscopic and flow cytometric approaches demonstrated the emergence of CVB3 capsid proteins at 8 h posttransfection, followed by morphological transformation of the cells. The morphological changes included formation of membranous protrusions containing viral capsids, together with microtubules and actin. Translocation of viral capsids into these protrusions was sensitive to cytochalasin D, suggesting the …
Analysis of the depth of field of integral imaging displays based on wave optics.
2013
In this paper, we analyze the depth of field (DOF) of integral imaging displays based on wave optics. With considering the diffraction effect, we analyze the intensity distribution of light with multiple micro-lenses and derive a DOF calculation formula for integral imaging display system. We study the variations of DOF values with different system parameters. Experimental results are provided to verify the accuracy of the theoretical analysis. The analyses and experimental results presented in this paper could be beneficial for better understanding and designing of integral imaging displays.
Modelling Polycrystalline Materials: An Overview of Three-Dimensional Grain-Scale Mechanical Models
2014
International audience; A survey of recent contributions on three-dimensional grain-scale mechanical modelling of polycrystalline materials is given in this work. The analysis of material micro-structures requires the generation of reliable micro-morphologies and affordable computational meshes as well as the description of the mechanical behavior of the elementary constituents and their interactions. The polycrystalline microstructure is characterized by the topology, morphology and crystallographic orientations of the individual grains and by the grain interfaces and microstructural defects, within the bulk grains and at the inter-granular interfaces. Their analysis has been until recentl…
3D part inspection path planning of a laser scanner with control on the uncertainty
2011
International audience; This article concerns the measurement process of mechanical parts using laser scanners. From the point of view of industrial applications, the objective is to guarantee the measurement accuracy during the scanning with regard to the geometrical product specifications. The proposed method can be summarized as follow: the first step consists of analyzing the interval of tolerance for the different specifications and to attribute to every geometrical entity a maximal uncertainty of measurement. This uncertainty depends on the angle of incidence between the laser plane and the scanned surface. In the second step, an approach based on the concept of visibility is used fro…
Path Planning in Inspection Process of 3-D Parts Used the Visibility Technique
2006
International audience; In this paper presents a new method for digitalization of parts with non-contact sensor remains nevertheless complex. It is not completely solved today, in particular from a metrological point of view. In this article, we consider the determination of the trajectory planning within the framework of the control of dimensional and geometrical specifications. The sensor used in this application is a laser planner scanner with CCD camera oriented and moved by a CMM. Thus, we seek to determine which are the best possible orientations of the sensor with respect to the geometrical specifications of the measured part, giving the admissible measurement uncertainties. The deve…