Search results for "Surface reconstruction"
showing 10 items of 23 documents
Quality Assessment of Reconstruction and Relighting from RTI Images: Application to Manufactured Surfaces
2019
In this paper, we propose to evaluate the quality of the reconstruction and relighting from images acquired by a Reflectance Transformation Imaging (RTI) device. Three relighting models, namely the PTM, HSH and DMD, are evaluated using PSNR and SSIM. A visual assessment of how the reconstructed surfaces are perceived is also carried out through a sensory experiment. This study allows to estimate the relevance of these models to reproduce the appearance of the manufactured surfaces. It also shows that DMD reproduces the most accurate reconstruction/relighting to an acquired measurement and that a higher sampling density don't mean necessarily a higher perceptual quality.
Low-Cost Optical Mapping Systems for Panoramic Imaging of Complex Arrhythmias and Drug-Action in Translational Heart Models.
2017
[EN] Panoramic optical mapping is the primary method for imaging electrophysiological activity from the entire outer surface of Langendorff-perfused hearts. To date, it is the only method of simultaneously measuring multiple key electrophysiological parameters, such as transmembrane voltage and intracellular free calcium, at high spatial and temporal resolution. Despite the impact it has already had on the fields of cardiac arrhythmias and whole-heart computational modeling, present-day system designs precludes its adoption by the broader cardiovascular research community because of their high costs. Taking advantage of recent technological advances, we developed and validated low-cost opti…
High Quality Reconstruction of Dynamic Objects using 2D-3D Camera Fusion
2017
International audience; In this paper, we propose a complete pipeline for high quality reconstruction of dynamic objects using 2D-3D camera setup attached to a moving vehicle. Starting from the segmented motion trajectories of individual objects, we compute their precise motion parameters, register multiple sparse point clouds to increase the density, and develop a smooth and textured surface from the dense (but scattered) point cloud. The success of our method relies on the proposed optimization framework for accurate motion estimation between two sparse point clouds. Our formulation for fusing it closest-point and it consensus based motion estimations, respectively in the absence and pres…
Reflectance-based surface saliency
2017
In this paper, we propose an original methodology allowing the computation of the saliency maps for high dimensional RTI data (Reflectance Transformation Imaging). Unlike most of the classical methods, our approach aims at devising an intrinsic visual saliency of the surface, independent of the sensor (image) and the geometry of the scene (light-object-camera). From RTI data, we use the DMD (Discrete Modal Decomposition) technique for the angular reflectance reconstruction, which we extend by a new transformation on the modal basis enabling a rotation-invariant representation of reconstructed reflectances. This orientation-invariance of the resulting reflectance shapes fosters a robust esti…
Surface Reconstruction Based on a Descriptive Approach
2000
The design of complex surfaces is generally hard to achieve. A natural method consists in the subdivision of the global surface into basic surface elements. The different elements are independently designed and then assembled together to represent the final surface. This method requires a classification and a formal description of the basic elements. This chapter presents a general framework for surface description, based on a constructive tree approach. In this tree the leaves are surface primitives and the nodes are constructive operators.
Calculations of the atomic structure of the KNbO3 (110) surface
2000
Abstract The O-terminated KNbO 3 (110) surface is modeled using a semi-empirical shell model and two different short-range interatomic potentials. We find this surface to be unstable with respect to a strong reconstruction and K-termination. This conclusion is confirmed by preliminary calculations using the ab initio linear combination of atomic orbitals (LCAO) formalism.
Box 5: Surface Crystallography Terminology
2009
The crystalline nature of the surface differs from the bulk because atoms on the surface experience a different force field due to unterminated bonds, oxidation by adatoms etc. [1]. Free energy minimisation leads to reconstruction of the surface layer from the bulk by formation of dimers and displacement of atoms from their normal sites.
Model of the catalyticA+B→0reaction with surface reconstruction
2002
The $A+\stackrel{\ensuremath{\rightarrow}}{B}0$ reaction model with a surface reconstruction is analyzed. It is compared with another similar model for the ${A+1/2B}_{2}\ensuremath{\rightarrow}0$ reaction [V. N. Kuzovkov et al., J. Chem. Phys. 108, 5571 (1998)], which mimics the CO oxidation reaction on the Pt surfaces. The effect of monomer B adsorption instead of dimer ${B}_{2}$ is examined. It is shown that qualitative system features such as reactant concentration oscillations are independent of this substitution.
Hand Held 3D Scanning for Cultural Heritage: Experimenting Low Cost Structure Sensor Scan
2017
In the last years 3D scanning has become an important resource in many fields, in particular it has played a key role in study and preservation of Cultural Heritage. Moreover today, thanks to the miniaturization of electronic components, it has been possible produce a new category of 3D scanners, also known as handheld scanners. Handheld scanners combine a relatively low cost with the advantage of the portability. The aim of this chapter is two-fold: first, a survey about the most recent 3D handheld scanners is presented. As second, a study about the possibility to employ the handheld scanners in the field of Cultural Heritage is conducted. In this investigation, a doorway of the Benedictin…
Density functional study of gold atoms and clusters on a graphite (0001) surface with defects
2006
Adsorption of gold atoms and clusters $(N=6)$ on a graphite (0001) surface with defects has been studied using density functional theory. In addition to perfect graphite (0001), three types of surface defects have been considered: a surface vacancy (hole), a pyridinelike defect comprising three grouped nitrogen atoms, and a substitutional doping by N or B. Results for Au and ${\mathrm{Au}}_{6}$ indicate that the surface vacancy can form chemical bonds with Au as the three nearby carbons align their dangling bonds towards the gold particle (binding energy 2.4--$2.6\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$). A similar chemically saturated holelike construction with three pyridinic N atoms resul…