Search results for "RECONSTRUCTION"

Performance evaluation of a high resolution dedicated breast PET scanner

2016

Purpose: Early stage breast cancers may not be visible on a whole-body PET scan. To overcome whole-body PET limitations, several dedicated breast positron emission tomography (DbPET) systems have emerged nowadays aiming to improve spatial resolution. In this work the authors evaluate the performance of a high resolution dedicated breast PET scanner (Mammi-PET, Oncovision). Methods: Global status, uniformity, sensitivity, energy, and spatial resolution were measured. Spheres of different sizes (2.5, 4, 5, and 6 mm diameter) and various 18 fluorodeoxyglucose (18F-FDG) activity concentrations were randomly inserted in a gelatine breast phantom developed at our institution. Several lesion-to-ba…

Reconstruction of the weight-bearing surface of the foot with free flaps

2015

Sea Surface Temperatures and Paleoenvironmental Variability in the Central Mediterranean During Historical Times Reconstructed Using Planktonic Foram…

2019

The ongoing anthropogenic‐induced warming assessment requires a robust background from regional sea surface temperature (SST) reconstructions. Planktonic foraminifera have yielded valuable insights into late Quaternary SST dynamics, but the techniques to estimate SST from fossil assemblages have only rarely been used in very recent sedimentary records (the last 2,000 years). Here we use two transfer function methods, modern analog technique and artificial neural networks, to reconstruct SST variability in two cores from the Central Mediterranean Sea that span the last five centuries. Both cores show similar and considerable changes in the planktonic foraminifera assemblages. However, the in…

Graphic proposal for the great hall of the Palace of the Counts of Oliva

2021

[EN] The now-demolished Palace of the Counts of Oliva, in the province of Valencia (Spain), was an outstanding example of late Gothic and early Renaissance architecture and art. Its great hall was particularly impressive, with rich, complex decoration that constituted a cultural milestone linked recently to the ‘Germanías’, or Brotherhoods. Through research conducted in image and document collections, a graphic reproduction of the room has been produced, with special emphasis on its frieze. The procedures and techniques used in this process are examined here, before a final contemplation of the possible uses for these results.

Textureless macula swelling detection with multiple retinal fundus images

2011

Retinal fundus images acquired with nonmydriatic digital fundus cameras are versatile tools for the diagnosis of various retinal diseases. Because of the ease of use of newer camera models and their relatively low cost, these cameras can be employed by operators with limited training for telemedicine or point-of-care (PoC) applications. We propose a novel technique that uses uncalibrated multiple-view fundus images to analyze the swelling of the macula. This innovation enables the detection and quantitative measurement of swollen areas by remote ophthalmologists. This capability is not available with a single image and prone to error with stereo fundus cameras. We also present automatic alg…

Spatial Diagnostics of Hg/Ar and Hg/Xe Discharge Lamps by Means of Tomography

2011

In this work, the diagnostics using tomography in Hg/Xe and Hg/Ar capillary lamps is presented. First, the imaging of the lamps was performed using selected emission lines of mercury, argon and xenon in different operation conditions. Thus the tomographic reconstruction was made, to determine the spatial distribution of the emitting Hg and rare gas atoms. Significant differences of the distribution of the emitting atoms have been found in vertical and horizontal operation positions. The emitting mercury atoms in the state 73S1 were differently distributed within the lamp in the vertical and horizontal lamp positions. The radial profile has demonstrated a substantial depletion of the popula…

Robust Light Field Watermarking by 4D Wavelet Transform

2020

Unlike common 2D images, the light field representation of a scene delivers spatial and angular description which is of paramount importance for 3D reconstruction. Despite the numerous methods proposed for 2D image watermarking, such methods do not address the angular information of the light field. Hence the exploitation of such methods may cause severe destruction of the angular information. In this paper, we propose a novel method for light field watermarking with extensive consideration of the spatial and angular information. Considering the 4D innate of the light field, the proposed method incorporates 4D wavelet for the purpose of watermarking and converts the heavily-correlated chann…

Low-cost approximate reconstructing of heterogeneous microstructures

2016

We propose an approximate reconstruction of random heterogeneous microstructures using the two-exponent power-law (TEPL). This rule originates from the entropic descriptor (ED) that is a multi-scale measure of spatial inhomogeneity for a given microstructure. A digitized target sample is a cube of linear size L in voxels. Then, a number of trial configurations can be generated by a model of overlapping spheres of a fixed radius, which are randomly distributed on a regular lattice. The TEPL describes the averaged maximum of the ED as a function of the phase concentration and the radius. Thus, it can be used to determine the radius. The suggested approach is tested on surrogate samples of cer…

Field Reconstruction for Modeling Multiple Faults in Permanent Magnet Synchronous Motors in Transient States

2021

Conventional field reconstruction model (FRM) for electrical machines has proved its main strength in efficient computations of magnetic fields and forces in healthy permanent magnet synchronous machines (PMSM) or faulty machines in steady states. This study aims to develop a magnet library of different magnet defects and include inter-turn short-circuit (ITSC) in the FRM for PMSM. The developed FRM can model a combination fault between ITSC, and magnet defect in a PMSM in transient states. Within the framework, an 8-turn ITSC was modelled in both finite element analysis (FEA) and FRM, and then identified by the extended Park’s vector approach. The air-gap magnetic field reproduced b…

An efficient method for fully automatic 3D digitization of unknown objects

2013

Our goal is to develop a complete and automatic scanning strategy with minimum prior information about the object shape. We aim to establish a methodology for the automation of the 3D digitization process. The paper presents a novel approach to determine the Next Best View (NBV) for an efficient reconstruction of highly accurate 3D models. Our method is based on the classification of the acquired surfaces into Well Visible and Barely Visible combined with a best view selection algorithm based on mean shift, which avoids unreachable positions. Our approach is applicable to all kinds of range sensors. To prove the efficiency and the robustness of our method, test objects are first scanned man…