共查询到20条相似文献,搜索用时 194 毫秒
1.
2.
3.
基于三角划分的多连通域图形匹配研究 总被引:1,自引:0,他引:1
由若干个多边形通过组合产生的具有多个连通域的多连通域图形识别问题是工程图纸识别与理解所要解决的重要问题。首先,通过建立包围多边形、连通多边形概念,完成对多连通域图形的表示;然后,依据最近距离、无遮挡、包含原则添加辅助线,实现三角划分,解决了包含连通的定位问题。在匹配过程中,首先通过匹配包围多边形实现多连通域图形的外轮廓定位;然后通过匹配连通多边形删除连通域,逐步收缩图形,实现图形匹配。应用此方法,解决了多连通域图形的旋转、缩放匹配问题,在汽车线束图纸识别中取得了良好的应用效果。 相似文献
4.
5.
针对理论上属于NPC问题的非规则件优化排样问题,论文提出一种基于小生境技术的自适应遗传模拟退火算法与基于内靠接临界多边形最低点的启发式布局算法相结合的方法。考虑到算法中交叉概率和变异概率的选择影响到算法收敛性,提出了自适应的交叉概率和变异概率,通过基于小生境技术的遗传模拟退火算法对非规则件排样的最优顺序和各自的旋转角度进行优化搜索。将非规则件定位在有缺陷原材料和非规则件多边形的内靠接临界多边形最低点以实现个体的解码,同时避开了原材料表面缺陷。排样实例表明,该优化排样算法行之有效,具有广泛的适应性。 相似文献
6.
简单多边形方向及顶点凹凸性的快速判定 总被引:4,自引:1,他引:4
基于简单多边形方向与顶点凹凸性的内在联系,采用极值点性质判定多边形方向,通过多边形顶点坐标判定其拓扑映射点之间的位置关系,结合以上两方面对顶点的凹凸性作出判断。对基于拓扑映射的多边形顶点凹凸判别算法作出有效的改进,避免了原算法申大量的重复计算。实践证明,有效的减少计算次数,提高了效率。 相似文献
7.
为提高多点声源工况的定位精确度及简化设备,对传统波束形成算法进行改进。引入改进扫描中的扫描向量并结合遗传算法对求解域内的非线性方程组进行求解,从而提高定位精度。基于改进算法,在消声室内采用空间星型(Y型)传感器阵列对不同声源进行定位,并将结果与传统算法定位结果进行比较。由比较可见:当多个声源相距较近时,这些源等效于单一点源,两种算法定位结果基本一致;但当声源相互距离增大时,改进算法可以有效提高定位精度,并准确定位多个源的位置。 相似文献
8.
9.
10.
11.
A rigorous vector analysis is performed to investigate the structure of the scan field produced by a rotating polygon, and it is shown that the scan field is asymmetric to the ray reflected by the polygon at a neutral scan position. Some fundamental aspects of the polygon scanning systems are addressed, such as the scan duty cycle, the locus of the scan center, the depth of the scan field, and the off-axis defocus in convergent beam scanning. 相似文献
12.
13.
14.
Howard D. Cohen 《International journal for numerical methods in engineering》1980,15(3):470-476
An algorithm is given to discretize a polygon or curved surface into triangular arrays. The method first involves the manual division of the array into quadrilaterals with specified numbers on rows and columns. The individual points are then filled in automatically and elements are automatically generated. A point of particular importance is that the number of columns or rows may be made to change. A subroutine is given to perform this task. 相似文献
15.
论文提出了一种高效稳定的多边形裁剪算法,算法支持带内环的平面简单多边形,同时也支持多边形的“并”和“差”等布尔运算.首先,设计了算法所需的数据结构;其次,基于直线扫描转换Bresenham算法原理提出了边网格划分的有效算法,并应用一个简单的方法避免不同网格内边的重复求交;最后,将交点分类为普通交点和顶交点,并针对这两类交点构造了不同的跟踪策略,在跟踪过程中交替、递归地应用这两个策略来确保算法处理特殊情况时的稳定性.与其它同类算法的比较表明,新算法具有更高的效率. 相似文献
16.
Walters CT 《Applied optics》1995,34(13):2220-2225
A general two-dimensional ray-trace analysis is presented for the motion of a geometric focal point over a flat surface provided by a postobjective rotating polygon laser beam scanner. The exact defocus equation is derived for any value of the neutral scan position deflection angle and the polygon rotation angle. The scan nonlinearity is derived for the special case of a zero neutral scan deflection angle. Geometric parameters were found that reduce the peak-to-peak defocus by more than an order of magnitude from that found in previous design approaches. Conditions were also found that reduce scan nonlinearity to less than 2 × 10(-4). Practical limitations, such as large polygons and beam obscurations, encountered in the implementation of postobjective scanning are discussed. 相似文献
17.
18.
In this paper, a hybrid approach, employing both genetic and heuristic algorithms, is proposed for nesting of different rectangular parts in multiple rectangular sheets with the objective of utilizing the sheet material effectively. The proposed genetic approach gives the best sequence of sheets and parts to generate an effective nested pattern with a heuristic algorithm. The heuristic approach arranges each of the parts in the bottom-left-most position of the sheet(s) by considering the sequence of sheets and parts given by the genetic algorithm. The effectiveness of the proposed approach is shown by comparing the results obtained with the present approach to those obtained by Jakobs' (1996, European Journal of Operational Research , 88 , 165-181) approach when all the parts are nested in a single sheet. Finally, the application of the current approach for nesting of rectangular parts in multiple sheets is illustrated. 相似文献
19.
生成正多边形和圆的新算法 总被引:1,自引:0,他引:1
针对正多边形各顶点坐标的计算,构造了新的递推公式并加以证明。以新公式为基础给出了正多边形和圆生成算法,并对算法误差进行了分析。计算正多边形每个顶点需要两次乘法和两次加法,优于目前"多边形逼近法"所采用的顶点计算方法。算法具有构造简单、执行速度较快和精度高的特点。理论分析和上机验证算法可行,完全可以满足常规的应用。 相似文献
20.
The efficient nesting of shapes is an important consideration in industries as diverse as ship building and shoe making. Optimum layouts yield significant savings in material, and consequently lead to lower unit cost of components. This paper considers how any shape, including concavities and circular sections, can be approximated to a polygon and determines the hexagonal paver that circumscribes this convex polygon for minimum area addition. Previous studies have shown that no convex polygon with more than six sides can be fitted side by side to give continuous surface covering of a plane. 相似文献