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Search Results: 1 - 10 of 13207 matches for " Surface Reconstruction "
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Survey of Surface Reconstruction Algorithms  [PDF]
Amin Alqudah
Journal of Signal and Information Processing (JSIP) , 2014, DOI: 10.4236/jsip.2014.53009
Abstract:

Surface reconstruction is a problem in the field of computational geometry that is concerned with recreating a surface from scattered data points sampled from an unknown surface. To date, the primary application of surface reconstruction algorithms has been in computer graphics, where physical models are digitized in three dimensions with laser range scanners or mechanical digitizing probes (Bernardini et al., 1999 [1]). Surface reconstruction algorithms are used to convert the set of digitized points into a wire frame mesh model, which can be colored, textured, shaded, and placed into a 3D scene (in a movie or television commercial, for example). In this paper, we discuss some computational geometry preliminaries, and then move on to a summary of some different techniques used to address the surface reconstruction problem. The coming sections describe two algorithms: that of Hoppe, et al. (1992 [2]) and Amenta, et al. (1998 [3]

Transplante de membrana amniótica
Moreira, Hamilton;Oliveira, Cinara S. de;
Arquivos Brasileiros de Oftalmologia , 2000, DOI: 10.1590/S0004-27492000000400012
Abstract: amniotic membrane transplantation has been used as an alternative for ocular surface reconstruction. indications for amniotic membrane transplantation include persistent epithelial defects, pterygium, stevens-johnson syndrome, ocular cicatricial pemphigoid, chemical burns and pseudo-phakik bullous keratopathy.
The reconstruction of fossil planation surface in China
Jinliang Feng,Zhijiu Cui
Chinese Science Bulletin , 2002, DOI: 10.1360/02tb9101
Abstract: On the basis of results of relative subjects, the fossil planation surface has been discussed by the authors from the point of geomorphologic view. The discussion contents included the characteristic information, research methods, paleotopography (gradient and altitude) and other problems about fossil planation surface. The recognition and reconstruction of fossil planation surface mainly rely on the following characteristic information: (i) the character of erosion unconformity surface; (ii) the paleo-weathering crust and residual deposits; (iii) the paleo-karst and filled deposit in the paleo-karst under the unconformity surface, and (iv) the character and environment of sediment above the unconformity surface. According to the above-mentioned characteristic information, the authors recognized and reconstructed two stages of fossil planation surface on Paleo-land of North China and Yangtze Paleo-land. These two fossil planation surfaces formed from Middle Ordovician to Lower Carboniferous and from Lower Permian to Upper Permian respectively. The paleo-gradient of fossil planation surface changed within 0.31‰–1.32‰, mostly less than 1.0‰ According to the developing depth of paleo-karst, the authors considered that in Suqiao buried-hill region of Paleo-land of North China, the paleo-altitude is 300 m or so above paleo-sea-level. The authors hope that the research is in favor of discussion about rising scale and process of the Tibetan Plateau. Besides, the research of fossil planation surface can provide a theoretical base for relative research, such as the reconstruction of paleoenvironment, the evolution and drift of paleo-continent, the formation and distribution of weathering ore deposits, the reservior and prospection of oil and gas, etc.
Surface reconstruction on stishovite SiO2, HfO2 and rutile TiO2 (001)

Tang Fu-Ling,Yue Rui,Lu Wen-Jiang,

中国物理 B , 2011,
Abstract: This paper systematically investigates the surface reconstruction processes and patterns on stishovite SiO2, HfO2 and rutile TiO2 (001) by using classical molecular dynamics. It is found that these three surfaces relax instead of reconstruction at 0 K, and have little possibility to reconstruct below 40 K. Above 40 K, surface reconstructions take place as collective atomic motion which can be speeded by higher temperature or compressed strain. Several reconstruction patterns with approximate surface energies are found, and electrostatic potentials on them are also provided in comparison with possible microscopic results.
Investigation of the Hysteretic Phenomena in RHEED Intensity Change in the Study of Surface Reconstruction
ákos Nemcsics,Jen? Takács
Acta Polytechnica Hungarica , 2010,
Abstract: This paper describes a study of the RHEED intensity change against temperaturein case of GaAs and InAs surfaces. RHEED as a technique is a widely used monitoringmethod for observing molecular-beam-epitaxial (MBE) growth. The reconstruction andother changes of the surface can be investigated by observing the RHEED pattern. Both thestatic and the dynamic RHEED-s are very complex phenomena, but these effects can beused as versatile tools for in-situ monitoring of the growth of the epitaxial layer, in spite ofthe fact that we do not know much about the details of its nature. Our observations showedthat the specular beam intensity of RHEED had changed with the change of the surfacetemperature. We investigated the changes of the GaAs and InAs (001) surfaces by using thiseffect. The change in intensity follows the observed surface reconstruction. This change inthe RHEED intensity against temperature shows hysteretic properties, with a differentcharacter for each material. So far, the explanations for these phenomena were different inboth cases. Here, we explain these hysteretic phenomena in general terms with the T(x)hyperbolic model for coupled hysteretic systems, which is applicable to both materials.Experimental results presented in the paper are in good agreement with the modelpredictions.
Combination of Deterministic and Stochastic Aproaches to the Image Reconstruction
Jarmila Dedkova
Advances in Electrical and Electronic Engineering , 2008,
Abstract: In this paper is described a new algorithm based on the combination of deterministic and stochastic approaches to the reconstruction process of the surface conductivity distribution to obtain the best results. The images of the electrical surface conductivity distribution can be reconstructed from voltage measurement captured on the boundaries of an object. The image reconstruction problem is an ill-posed inverse problem of finding such surface conductivity that minimizes the suitable optimisation criterion. The advantages of a new approach are compared with properties of deterministic and stochastic approaches during the same image reconstructions. It will be shown that proposed algorithm is a very effective way to obtain the satisfying identification of cracks in special structures called honeycombs.
基于变分水平集方法的散乱数据曲面重构研究
Surface Reconstruction from Scattered Data Based on Variational Level Set Method
 [PDF]

朱云云, 朱华平
Journal of Image and Signal Processing (JISP) , 2016, DOI: 10.12677/JISP.2016.52007
Abstract:
工程学和医学等领域中的很多问题进行抽象后可转化为散乱数据的光滑曲面重构问题。在散乱数据附近设定初始轮廓,将初始轮廓间接地表示为水平集函数的零水平集形式,最终将初始活动轮廓的演化转化成水平集函数的演化。定义一个以水平集函数为自变量的能量泛函来度量它与散乱点的逼近程度,利用改进的变分水平集方法演化初始轮廓,达到重构目的。本文中,一是对Heaviside函数进行改进,使初始轮廓能更好的收敛于目标轮廓;二是给出了模型数值计算的具体过程,并以二维实例说明散乱数据重构的效果。
A lot of problems in the field of engineering and medicine after abstraction can be converted into scattered data reconfiguration problems. We set initial contour near the scattered data, expressed as the zero level set of the level set function, which will eventually turn the evolution of initial active contour into the evolution of the level set function. We define an energy functional who takes the level set function as its independent variable, to measure approximation degree with the scattered data, and use the improved variational level set method to evolve the initial contour and achieve reconstruction. In this paper, firstly, putting forward an improved Heaviside function to make the initial contour can better converge in the target contour; secondly, the specific process of numerical calculation model is given, and a two-dimensional example illustrates the effect of the scattered data reconstruction.
Scanning tunneling microscopy study of surface reconstruction induced by N adsorption on Cu (100) surface

Dou Wei-Dong,Zhang Han-Jie,Bao Shi-Ning,

中国物理 B , 2010,
Abstract: The reconstructed structure of Cu (100) surface induced by atomic N adsorption is studied by using scanning tunneling microscopy (STM). The 2D structure of copper boundary between neighbouring N covered islands is found to be sensitive to the growth conditions, e.g. N+ bombardment time and annealing temperature. The copper boundary experiences a transition from nano-scale stripe to nano-particle when the substrate is continuously annealed at 623~K for a longer time. A well-defined copper-stripe network can be achieved by precisely controlling the growth conditions, which highlights the possibility of producing new templates for nanofabrication.
A smart surface from natural rubber: the mechanism of entropic control at the surface monitored by contact angle measurement
Sureurg Khongtong
Songklanakarin Journal of Science and Technology , 2006,
Abstract: Surface oxidation of crosslinked natural rubber provided a hydrophilic substrate (sticky surface) that became more hydrophobic (less sticky) when equilibrated against hot water. This unusual temperaturedependent surface reconstruction is interpreted as the result of recoiling of entropic unfavorable uncoiled chains induced when rubber surface was oxidized. Subsequent equilibration of these annealed samples against water at room temperature returned their original hydrophilicity. The degree of this surface reconstruction and its kinetics are also dependent on the amounts of crosslinking of the samples.
A Method for Surface Reconstruction Based on Support Vector Machine
Lianwei Zhang,Wei Wang,Yan Li,Xiaolin Liu
Journal of Computers , 2009, DOI: 10.4304/jcp.4.9.806-812
Abstract: Surface reconstruction is one of the main parts of reverse engineering and environment modeling. In this paper a method for reconstruct surface based on Support Vector Machine (SVM) is proposed. In order to overcome the inefficiency of SVM, a feature-preserved nonuniform simplification method is employed to simplify cloud points set. The points set is reduced while the feature is preserved after simplification. Then a reconstruction method based on segmented data is proposed to accelerate SVM regression process for cloud data. Firstly, the original sampling data set is partitioned to generate several training data subsets and testing data subsets. A segmentation technique is adopted to keep the continuity on the borders. Secondly regression calculation is executed on every training subset to generate a SVM model, from which a segmented mesh is obtained according to the testing data subset. Finally, all the mesh surfaces are stitched into one whole surface. Both theoretical analysis and experimental result show that the segmentation technique presented in this paper is efficient to improve the performance of the SVM regression, while keeping the continuity of the subset borders.
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