一种建立包裹圆提取建筑物LiDAR点云边缘点的新算法

为提高变换域通信系统多址接入性能,降低系统误比特率,提出基于改进型Logistic混沌序列的变换域扩频编码通信系统。利用扩频序列优选原则,选取改进型Logistic混沌序列作为扩频序列,对m序列产生的随机相位矢量进行相位编码形成扩频基函数的扩频随机相位矢量。仿真结果表明,该扩频基函数具有更好的随机性,产生的扩频随机相位矢量互(自)相关性能优于传统基函数产生的随机相位矢量;在2个用户和多用户条件下,其信噪比增益和误比特性能都要优于传统基函数和基于Gold序列的扩频基函数,显著提高系统抗干扰性能,能更好地实现TDCS多址接入。

An algorithm of building pack circle to extract LiDAR edge point

The data of Light Detection And Ranging(LiDAR)is discrete three-dimensional point cloud, and the 3D laser foot points belonging to the same building have the characteristics of random distribution. Because of varied and complex shape of building, and complex environment around building, it results in that extracting borderline of building become more difficult. Extracting borderline, the most important is extracting the edge point. In the paper, a new algorithm of extracting the edge point is presented. Firstly, set an specific radius and threshold. Secondly, regard the first point as the centre of a circle and build a pack circle. Thirdly, acquire the distance between the centre and other points, and count the number in the pack circle. And then, go on repeating the operation throughout all point in the point cloud. Finally, compare the point number in every pack circle with threshold, to extract the edge point. By means of simulation, compared to alpha shape algorithm, this algorithm can reduce the running time based on a good effect.