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1.
提出了一种全自动、多模态的信息融合解决方案用于配准视频图像和磁跟踪数据。该配准方案将用于内窥镜图像的三维数字成像系统以对人体的三维解剖结构的外观和尺度进行重建,特别是用于微创手术。多模态标定方法如下:首先医生将磁跟踪器插入并固定于内窥镜的工作通道;然后利用该器械组对一个棋盘格模板的各个视角进行若干秒的采集;内窥镜坐标和磁跟踪器坐标的相对关系(平移和旋转)就可以立刻得到。在手术过程中,磁跟踪器显示的读数将可以自动用来推算出内窥镜的坐标(位置和朝向),并有利于重建器官的三维结构。虽然目前已有一些深入研究的算法用于从图像中推算相机的运动,他们通常非常容易受到图像分析、误差积累、结构形变等的影响。从实验结果分析可知,该方案提出使用磁跟踪器推算相机运动参数的方法可行且提高了精度。此外,该方法不需要特殊的训练或者昂贵的设备。  相似文献   

2.
基于灭点理论和平面控制场的相机标定方法研究   总被引:3,自引:0,他引:3       下载免费PDF全文
给出了一种基于灭点理论和平面控制场的相机解析自标定方法。在系统分析平面场景灭点几何的基础上,依据灭点理论并结合2维场景的共线方程严密论证和推导了平面控制场中相机外方位元素初值的实用算法。给出了一种圆形标志点的快速检测及定位方法,提出了一种基于计算可靠性矩阵QVVP的自检校光束法平差中各类观测值权值的确定方法。实验证明了该相机标定方法的正确性和有效性,为相机标定探索了一种可行的方法。  相似文献   

3.
A method for estimating a Lipschitz constant of the entropy operator of the Boltzmann type is suggested. Examples of the use of the obtained estimates in problems for restoring images by projections are given.__________Translated from Avtomatika i Telemekhanika, No. 7, 2005, pp. 54–65.Original Russian Text Copyright © 2005 by Popkov, Rublev.This work was supported by the Program “Branch of Information Technologies and Computer Systems” and the Russian Foundation for Basic Research, project no. 02-01-00198a.  相似文献   

4.
The object of the present paper is the investigation and study of (fuzzy) hyperideals in H v - semigroups. Regular equivalence relations play in H v - semigroup theory a role analogous to congruences in semigroup theory, so we introduce fuzzy regular equivalence relations on H v -semigroups and then we study fuzzy Rees regular relations on H v -semigroups. Using this ideas, we establish a relation between fuzzy hyperideal of an H v -semigroup H and fuzzy hyperideal of a quotient H v -semigroup of H. Some characterizations of them are then shown.   相似文献   

5.
6.
The method is suggested for the investigation of the existence, uniqueness, and localization of singular points of the DSEO class under consideration. The stability conditions are found “in the small” and “in the large.” Examples of the use of the obtained conditions are given.  相似文献   

7.
The influence of doping upon the phase change characteristics of Ge2Sb2Te5 (GST) has been determined with a variety of techniques including four-point-probe electrical resistance measurements, grazing incidence X-ray diffraction (XRD), X-ray reflectometry (XRR) and a variable incident angle spectroscopic ellipsometer (VASE) and a static tester. Doping with Bi, Sn or In maintains the NaCl-type crystalline structure of GST but expands the lattice due to the larger atomic radii. Sufficient optical contrast is exhibited and can be presumably correlated with the pronounced density change upon crystallization. In the Bi and Sn doped case transition temperatures are reduced with regard to the undoped case. Ultra-fast crystallization within 10 ns is demonstrated, which is correlated with a single NaCl-structure phase and a lower transition temperature arising from the weaker bonds. In the In doped case, however, crystallization is retarded, which can be correlated with the observed phase separation and the increased transition temperature.  相似文献   

8.
Given a closed, convex set X\subseteq \bbR n , containing the origin, we consider the problem (P) : max {c^\T x\colon x ∈ X} . We show that, for a fixed dimension, n , and fixed \eps , 0 <\eps<1 , the existence of a combinatorial, strongly polynomial \eps -approximation separation algorithm for the set X is equivalent to the existence of a combinatorial, strongly polynomial \eps -approximation optimization algorithm for the problem (P) . Received June 5, 1996; revised September 25, 1997.  相似文献   

9.
In order to examine the flow field and the radial segregation of silicon (Si) in a Ge x Si1-x melt with an idealized Czochralski (Cz) configuration, we conducted a series of unsteady three-dimensional (3-D) numerical simulations under zero-gravity conditions. The effect of convection driven by surface tension on the free surface of the melt was included in the model, by considering thermal, as well as solutal Marangoni convection. The concentration and flow fields at several stages during crystal growth are presented for several temperature differences, driving the Marangoni convection. The simulation results indicate that the flow and concentration fields are axisymmetric for Ma T < 625 and become oscillatory and 3-D for higher values. It was found that the maximum Si concentration difference at the growth interface decreases as thermal Marangoni number increases due to higher flow velocities in the vicinity of the interface. However, temporal fluctuations of Si concentration at the interface increase at higher thermal Marangoni numbers. The effects of aspect ratio (A r) were also considered in the model. It was found that the aspect ratio of the melt in the crucible has a prominent influence on the flow pattern in the melt which, in turn, effects the Si concentration at the growth interface.  相似文献   

10.
The structural transformation and transformation kinetics of Sb x Se100−x films (60 ≤ x ≤ 70) were studied to investigate the feasibility of applying Sb x Se100−x alloys in phase-change nonvolatile memories. The temperature-dependent van der Pauw measurements, Hall measurements, X-ray diffraction and a static tester were used to investigate the electrical properties and crystallization behavior of the Sb x Se100−x films. The sheet resistance difference between amorphous and crystalline state was higher than 104 Ω per square According to Hall measurement, Sb x Se100−x films have p-type conduction and the Hall mobility and carrier concentration increases with the increase in Sb content. The crystalline structure of the metastable phase of Sb x Se100−x alloys, which plays a major roll in fast crystallization, is similar to that of Sb2Te (rhombohedral structure). The transition temperature, sheet resistance and activation energy for transformation decrease as the amount of Sb increases in the Sb x Se100−x film. Applying the Kissinger method, the activation energies for crystallization were in the range from 1.90 ± 0.15 to 4.16 ± 0.28 eV. The desired crystallization speed can be obtained by a systematic change of the composition owing to the variation of the activation barrier with stoichiometry.  相似文献   

11.
We discuss the following problem which arises in robot motion planning, NC machining and computer animation: Given are a fixed surface Ψ and N positions Φi of a moving surface Φ such that the Φi are in point contact with Ψ. Compute a smooth and fair Euclidean gliding motion Φ(t) of the surface Φ on the surface Ψ which interpolates (or approximates) the given positions Φi at time instances ti. First we generalize interpolatory variational subdivision algorithms for curves to curves on surfaces. Second we study an unconstraint motion design algorithm which we then extend to the main contribution of this paper, an algorithm for the design of a motion constraint by a contacting surface pair. Both motion design algorithms use a feature point representation of the moving surface, subdivision algorithms for curves, instantaneous kinematics, and ideas from line geometry. Geometric methods are used for the numerical solution of the arising optimization problems.  相似文献   

12.
In previous centuries, several technical fields that are now engineering disciplines exhibited problems analogous to those frequently observed in software development today. This paper presents selected examples of experiences from some of those fields, especially electrical telegraphy and telephony during the second half of the 19th and the early 20th centuries, and compares them with difficulties, major mistakes, and so on, arising in software development today. It is the thesis of this paper that software development today is in a pre-engineering phase, analogous in many respects to the pre-engineering phases of the now traditional engineering disciplines. From observations regarding similarities between experiences in those fields in the past and software development today, questions are raised regarding lessons that software developers might learn from those earlier experiences of others-in particular, from the solutions they found to their problems. Some answers are suggested  相似文献   

13.
 Torsion classes of MV-algebras are defined as radical classes which are closed with respect to homomorphisms; in this paper we investigate their relations to radical classes of lattice ordered groups and to varieties of MV-algebras. Supported by Grant VEGA 1/9056/02.  相似文献   

14.
In this paper, a scheme is proposed for the preparation of the tripartite W state or W-like state of nonidentical particles. In our scheme, our required resources include two atoms and one cavity field, which makes our system become simple. Because each party included by W state has its own two possible states, and is not identical each other, one can easily distinguish them. Furthermore, we teleportate an unknown state of cavity field by using this W state as quantum channels. Our scheme of preparation employing a single high-Q superconducting cavity turns out to be attractive to realize based on present or future cavity QED techniques. Partially supported by Natural Science Foundation of Jiangxi, China, under Grant No. 0612006 and by the Scientific Research Foundation of Jiangxi Provincial Department of Education, China, under Grant No. [2007]191.  相似文献   

15.
Plasmodium of Physarum polycephalum is a large cell capable of solving graph-theoretic, optimization and computational geometry problems due to its unique foraging behavior. Also the plasmodium is a unique biological substrate that mimics universal storage modification machines, namely the Kolmogorov–Uspensky machine. In the plasmodium implementation of the storage modification machine data are represented by sources of nutrients and memory structure by protoplasmic tubes connecting the sources. In laboratory experiments and simulation we demonstrate how the plasmodium-based storage modification machine can be programmed. We show execution of the following operations with the active zone (where computation occurs): merge two active zones, multiply active zone, translate active zone from one data site to another, direct active zone. Results of the paper bear two-fold value: they provide a basis for programming unconventional devices based on biological substrates and also shed light on behavioral patterns of the plasmodium.  相似文献   

16.
The aim of this paper is to introduce the notion of fuzzy prime ideals of pseudo-MV algebras and investigate some of its properties.   相似文献   

17.
We present a simple theory of actions against the background of branching time, based on which we propose two versions of an extended stit theory, one equipped with particular actions and the other with sets of such actions. After reporting some basic results of a formal development of such a theory, we briefly explore its connection to a version of branching ETL.  相似文献   

18.
L is a language for specifying properties of reactive systems. Such properties are considered as sets of words over the alphabet defined by a specification. Properties that correspond to complements of such sets are not expressible in the language L. An approach is proposed to constructing formulas of the language L that specify approximations of complements of sets defined in L. These investigations were partially supported by INTAS grant 05-1000008-8144. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 18–26, November–December 2007.  相似文献   

19.
We present a method for construction of an approximate basis of the trace space H 1/2 based on a combination of the Steklov spectral method and a finite element approximation. Specifically, we approximate the Steklov eigenfunctions with respect to a particular finite element basis. Then solutions of elliptic boundary value problems with Dirichlet boundary conditions can be efficiently and accurately expanded in the discrete Steklov basis. We provide a reformulation of the discrete Steklov eigenproblem as a generalized eigenproblem that we solve by the implicitly restarted Arnoldi method of ARPACK. We include examples highlighting the computational properties of the proposed method for the solution of elliptic problems on bounded domains using both a conforming bilinear finite element and a non-conforming harmonic finite element. In addition, we document the efficiency of the proposed method by solving a Dirichlet problem for the Laplace equation on a densely perforated domain.  相似文献   

20.
跟随我国电力体制的深入改革,输电线路的构建规模持续扩大,经济的高速发展、社会的不断进步和人民生活水平的逐步提高都对电力系统运行的安全性提出了更高要求,为了跟上当前这种形式,满足全社会不断提高的用电需求,供电企业必须增强对输电线路安全质量的管控。国网龙岩供电公司以“一六八”新时代发展战略体系为核心,基于“互联网+”和“大数据”技术的发展,以完善传统巡检模式的不足为导向,以推动输电交互式巡检安全质量管控为引领,构建以“过程管控”为目的的输电交互巡检管控模式,搭建“工学一体”的信息交流平台,形成“全程记录”巡检数据库体系,全方位提升巡检工作安全质量及效率。该管控体系应用后,确实能确保巡检数据完整性,减少缺陷隐患漏报率,缩短现场紧急事件响应时间、新人培训上岗时间、常用报表统计时间等,能全面提升巡检安全质量。  相似文献   

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