The algorithm is explained in detail , based on classifying ccd image , the normal is obtained . the gray barycenter on the normal is contour point 该方法首先对图像分类，对直线段，圆弧段采取不同方法计算出法线，求出法线上的灰度重心点，从而将此点作为轮廓点。
We can achieve the recognition of airport through describing the shape of it with straight - line segments and distinguishing different objects with the length of the lines 通过用直线段来描述机场跑道的形状，以直线段的长度来区分不同的目标，可以达到识别机场目标的目的。
For the closed - curves consist of arcs and line segments , we present a fast approach to find intersections of closed - curve by extending park ' s polygonal chains intersection algorithm 对于圆弧和直线段组成的封闭曲线求交，本文通过拓展park多边形链求交方法提出了一个圆弧和直线段组成的封闭曲线求交方法。
This dissertation is about taking use of the merit of the traveling wave principle , exciting a traveling wave in a ring type stator with two tangential paths , generating the linear movement of the ultrasonic motor 本文研究利用行波原理的优点,在具有两个直线段的长环形结构中激励出行波,使马达产生直线运动的超声波直线马达。
By using multiple knot insertion techniques , cusps and straight - line segments allow to arise in the nuat b - spline interpolating curve , and its slackness and smoothness can be controlled by the change of the parameter 2 .通过重节点插入技术构造了带有尖点或直线段的混合插值曲线,分析了混合因子对插值曲线松弛性的调节作用
We extend this method to the problem of a domain which boundary is an open arc or an open segment . in this paper , we simulate the singularity of solution in extreme point of open arc or open segment by singular element 本文还把此方法推广到求解区域边界是直线段或者开弧段的情况，采用引入奇异边界单元的方法来模拟解在开边界端点附近的奇异性。
It is important to improve efficiency of curve intesection algorithm . in addition , a lot of curves are composed of arcs and line segments in engineering , such as the contour lines in machining fields 这是一个一般性方法，由于在离散的过程中通常会产生大量的小直线段，使得它的求交效率不高，因此提高求交效率是曲线求交方法研究中的一个关键问题。
A survey on recent progress in database research . journal of computer science and technology , 2003 , 18 : 538 - 552 . 23 papadopoulos a , manolopoulos y . parallel processing of nearest neighbor queries in declustered spatial data Ii引入了一个新颖的度量metric来减少查找空间，即将点到最小边界矩形mbr之间的距离扩展成直线段或轨迹段到mbr之间的距离。
Because straight - line segments represent the edge structure of the straight linear objects and meet the three properties as moving , rotating and scale inflexibility , it ' s effective for describing the shape of runways of the airport 由于直线段反映了目标的直线状结构特性，同时满足平移、旋转和尺度不变性的三个属性，这用来描述机场跑道的形状特征有效。
In the multiple - layered test for injection wells , a lot of pressure falloff curves in the single layers are hard to show a radial flow straight line due to the perturbative phenomena of multilayer reservoir , low permeability or short test time 摘要在注水井分层测试中，由于油藏的低渗透性或者测试时间相对较短等原因，各层的压力恢复曲线难以出现径向流直线段。
