A time-of-scan laser triangulation technique for distance measurements

This paper reports the development of an electro-optic device for relative distance measurement. The time-of-scan triangulation technique has been used as measurement principle and a rotating mirror employed as beam deflection system. A calibration technique is needed to calculate the geometrical parameters of the system. The device has an accuracy of 100 μm, a working distance of 20 cm and a range of 10 mm. The accuracy obtained depends on the instability of the rotation speed of the mechanical scanner that affects the measurement of the scanning time.     

N‐flips in even triangulations on the sphere

A triangulation is said to be even if each vertex has even degree. For even triangulations, define the N‐flip and the P2‐flip as two deformations preserving the number of vertices. We shall prove that any two even triangulations on the sphere with the same number of vertices can be transformed into each other by a sequence of N‐ and P2‐flips. © 2005 Wiley Periodicals, Inc. J. Graph Theory     

面聚类网格简化新算法

三维物体表面重建广泛采用三角网格方法,密集的数据采样可以重建出精确的三维表面,但是庞大的数据量不利于多分辨率三维实时显示和三维物体网络传输,因此三维表面网格简化是迫切需要解决的问题之一.近年来表面简化问题得到了广泛地研究.本文提出基于面聚类的网格简化新算法,通过最小化最大类内距离算法进行面聚类实现区域划分,然后提取区域特征,进而根据特征点和边对区域进行受限三角剖分.实验说明本文提出的面聚类网格简化算法在保持三维表面几何拓扑特征的基础上取得了很好的简化效果.     

三角形网格基活动图像编码研究——基本框架和I帧编码

本文结合实验结果,深入讨论了三角形网格基活动图像编码方法的基本框架和帧内编码问题。文中全面比较了DTM+MD的帧内编码方法和JPEG方法的性能,表明采用DTM+MD作帧内编码具有更好的主客观质量。     

Bivariate C1 Cubic Spline Spaces Over Even Stratified Triangulations

It is well-known that the basic properties of a bivariate spline space such as dimension and approximation order depend on the geometric structure of the partition. The dependence of geometric structure results in the fact that the dimension of a C ¹ cubic spline space over an arbitrary triangulation becomes a well-known open problem. In this paper, by employing a new group of smoothness conditions and conformality conditions, we determine the dimension of bivariate C ¹ cubic spline spaces over a so-called even stratified triangulation.     

Estimation of the Bezout number for piecewise algebraic curve

A piecewise algebraic curve is a curve determined by the zero set of a bivariate spline function.In this paper.a coniecture on trianguation is confirmed The relation between the piecewise linear algebraiccurve and four-color conjecture is also presented.By Morgan-Scott triangulation, we will show the instabilityof Bezout number of piecewise algebraic curves. By using the combinatorial optimization method,an upper     

Smooth surface reconstruction via natural neighbour interpolation of distance functions

We present an algorithm to reconstruct smooth surfaces of arbitrary topology from unorganised sample points and normals. The method uses natural neighbour interpolation, works in any dimension and accommodates non-uniform samples. The reconstructed surface interpolates the data points and is implicitly represented as the zero set of some pseudo-distance function. It can be meshed so as to satisfy a user-defined error bound, which makes the method especially relevant for small point sets. Experimental results are presented for surfaces in .     

Hamilton cycles in plane triangulations

We extend Whitney's Theorem that every plane triangulation without separating triangles is hamiltonian by allowing some separating triangles. More precisely, we define a decomposition of a plane triangulation G into 4‐connected ‘pieces,’ and show that if each piece shares a triangle with at most three other pieces then G is hamiltonian. We provide an example to show that our hypothesis that each piece shares a triangle with at most three other pieces' cannot be weakened to ‘four other pieces.’ As part of our proof, we also obtain new results on Tutte cycles through specified vertices in planar graphs. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 138–150, 2002     

基于线结构光的三维测量系统关键技术研究

提出了一种基于线激光、工业相机 、步进电机和 计算机的结构光的单目视觉三维扫描测量系统,阐述了其工作原理,建立几何数学模型,搭 建了系统试验平台,并基于灰度平方加权重心法提取光条中心。实验结果表明, 系统测量误差小于±0.03mm,光条中心提取精度达到亚像素级,满 足工业测量应用需求。