几何基础

High-level features including corners, doors and openings are identified and extracted which is the base for metric-topological map building.

在先验几何地图的基础上，本文讨论墙角、房门和通路等高级环境特征的辨识和提取，依据几何和拓扑环境模型实现几何—拓扑混合地图的构建。

Moreover, if the optimization problem has certain special feature, the simpler relaxation methods can be provided. For example, considering a generalized geometric programming problem, relevant relaxation linear programming can be obtained using its special structure. Based on the branch and bound method, a linear relaxation algorithm of global optimization is presented for generalized geometric programming, and the convergence of the algorithm is also proven.

此外，当优化问题具有某种特殊性质时，我们能给出更加简便的松弛化方法，如考虑广义几何规划问题，能充分利用其特殊结构，建立了广义几何规划问题的松弛线性规划问题；在分枝定界技术的基础上，提出了一个求广义几何规划全局解的线性松弛算法；证明了算法的收敛性。

In Chapter 1,some elementary knowledge was introduced,such as theBernstein-Bezier representation for polynomials,conform triangulation,theconditions of convexity for Bézier spline surfaces,the funtional andgeometric continuity condition for neibour Bézier surface patches etc.,specially,based on the Liu-Ding-Yuan Theorem for geometric continuity,some simple and practical conditions were obtained.

第一章介绍一些基本知识，如多项式的Bernstein-Bézier表示，相容三角剖分的定义，Bézier三角样条曲面保凸的条件，相邻Bézier曲面片函数连续和几何连续的条件等，特别地，在刘鼎元关于几何连续条件的一般定理的基础上，导出了几个较简单的实用的一阶几何连续条件。

Chapter 1 briefs the relation between invariance and computer vision and summarizes the research and application of invariance in computer vision. Chapter 2 first derives the transformations of three camera models, then makes the correpondences between the models and three typical geometrical transformation groups by analysing the transformations respectively. The correspondences supply the theoretical basis for applying geometrical invariants to resolve the problems of computer vision. In Chapter 3, we describe the geometrical invariant theory and prove some geometrical invariants of coplanar points, lines or conics by algebraic method. In order to use the invariants of conic pairs to describe general 2D shapes, we discuss the perspectively invariant representation of planar curves using conies in detail. A system consisted of two TMS320C25 and based on moment invariants is introduced in Chapter 5. The system can recognize more than 30 different shapes of object model or more than 10 plane models with similar shape in real time.

第一章简述了不变性与计算机视觉的关系，以及计算机视觉中的不变性研究和应用概况；第二章推导了计算机视觉中常用三种投影模型的变换关系，通过对这三种变换关系的分析，分别建立了这三种投影模型和几何学中的三种变换群之间的一一对应关系，为几何不变性在计算机视觉中的应用提供了理论基础；在第三章中，我们介绍了几何不变性的理论，并且用代数方法证明了共面点、直线、二次曲线的几何不变量和射影不变量；为了把二次曲线的不变量用于一般二维形状描述，在第四章中我们详细地讨论了用二次曲线实现一般平面曲线的透视不变性表示的方法；第五章介绍了用两片TMS320C25构成的、基于不变矩形特征的运动目标实时识别系统。

Furthermore,this course is benefitial to study differential topology, Riemannian Geometry, Lie group and Nonlinear Analysis etc.

为进一步学习微分几何、微分拓扑、几何分析、黎曼几何、李群、低维拓扑和非线性分析等相关课程奠定良好的基础，并为阅读当代数学文献创造条件。

This article also points out that"existence of squares","Out-In Complementary Principle","the principle of limit","Liu-Zu cross -section princeple","the area formula for rectangle and the volume formula for cuboid" determine the nature and lay the foundation of geometry in ancient China.

提出了我国古代论证几何所依据的原始命题，指出"存在正方形"连同"出入相补原理"、"极限原理"、"刘－祖截面原理"以及长方形面积公式和长方体体积公式确定了我国古代几何的性质，奠定了我国古代几何的基础。

The relationship of the optimal geometric distribution of the constellation and the positioning error is given.

在分析定位误差的基础上，研究了星座最佳几何配置，以及几何位置相对较好、星的个数较少的4颗卫星的定位问题，并给出了星座的最佳几何分布与定位误差的关系仿真。

Based on the inverse mapping with linear deformation, the geometric mapping was used to carry out the second element transformation in order to avoid the abnormality of the stiffness matrix and to improve the stability and the convergence of the numerical calculations.

在现有线性变形逆向映射法的基础上，采用几何映射法计算变换单元，避免单元刚度矩阵出现畸形，提高钣金展开有限元逆算法的稳定性和收敛速度，对几何映射法与投影法所计算的变换单元进行了对比，数值计算结果表明用几何映射法计算的初始估算展开料形状更接近于最终的钣金件展开形状。

Based on the summarizing of the exiting algorithms of the texture mapping and antialiasing, this paper goes deeply into the basic theory and processing of texture mapping. The texture compress algorithm which can satisfy the need of the memory and time is given for the stochastic sampling in the inverse texture mapping; the geometry transformation in the texture mapping are discussed and the concepts of the unitary parametrization and the patch parametrization is proposed, some kinds of the unitary parametrization methods of parametric surfaces and the geometry transformation in the patch parametrization are also presented; in order to solve the aliasing in the parametrization of intermediate surface-sphere in two-part texture mapping, an area-preserving transformation is presented also; to improve the quality of the graph the aliasing in the texture mapping is analyzed from the aspect of signal process, and the modified summed-area tables algorithms is proposed; the distortion of the scanline conversion algorithms under perspective transformation is analyzed and the proper interpolation algorithm is presented so the aliasing problem of the polyhedral object after the unitary parametrization is efficiently solved.

本文在总结现有的纹理映射和反走样算法的基础上，深入研究了纹理映射的基本原理与过程，根据反向纹理映射对纹理随机采样的特殊要求，提出了一种可满足存储空间和寻址时间的纹理压缩存储算法；通过对纹理映射中几何变换理论的进一步深入探讨，提出了整体参数化和面片参数化的概念，并给出了参数化曲面的各种整体参数化方法和面片参数化的几何变换形式；针对现有的两步映射算法所存在的中间曲面—球面的参数化问题，提出一种等积映射方法，较好地实现了由非参数化面片拼接而成的多面体表面的纹理映射；从信号采样的角度深入分析了纹理映射中走样产生的原因，提出了改进的区域求和表算法，使图形生成的效果有所提高；还分析了一般的扫描线算法在透视变换中所存在的问题，提出了一种正确的插值算法，从而解决了整体参数化后多面体表面纹理映射的几何变形问题。

Based on analysis and compare of all kinds of precept-sorting of feature of plastic product for the different structural plastic product, a 3D feature library of plastic product was built on the platform by integrating Feature-Modeling technique with parametric technique. The feature schleps its information of non-geometry by database-externed technique of the entity. After building the database of plastic material, the module of choice of plastic material is developed by technology of ODBC. The plastic product can be sculpted by calling of feature of plastic product and inputting parameters interactively.

针对不同结构类型的塑件，在全面分析、比较塑件特征分类的各种方案的基础上，采用三维特征建模技术和参数化技术，建立了注塑产品的三维特征库；应用实体扩展数据库技术，使特征携带非几何信息；再在建立塑料物性数据库的基础上，采用ODBC技术，开发了塑料材料选择模块；通过塑件特征的调用和人机交互输入参数的方法进行塑件三维造型，再把塑件的三维实体和塑件的非几何信息结合起来，生成塑件全信息模型。

Lugalbanda was a god and shepherd king of Uruk where he was worshipped for over a thousand years.

Lugalbanda 是神和被崇拜了一千年多 Uruk古埃及喜克索王朝国王。

I am coming just now,' and went on perfuming himself with Hunut, then he came and sat.

我来只是现在，'歼灭战perfuming自己与胡努特，那麼，他来到和SAT 。