Calibration method for multi-line structured light vision sensor based on Plücker line

For the rapid calibration of multi-line structured light system,a method based on Plücker line was proposed.Most of the conventional line-structured light calibration methods extract the feature points and transform the coordinates of points to obtain the plane equation.However,a large number of points lead to complicated operation which is not suitable for the application scenarios of multi-line structured light.To solve this issue,a new calibration method was proposed that applied the form of Plücker matrix throughout the whole calibration process,instead of using the point characteristics directly.The advantage of this method is that the light plane equation can be obtained quickly and accurately in the camera coordinate frame.Correspondingly a planar target particularly for calibrating multi-line structured light was also designed.The regular lines were transformed into Plücker lines by extending the two-dimensional image plane and defining a new image space.To transform the coordinate frame of Plücker lines,the perspective projection mathematical model was re-expressed based on the Plücker matrix.According to the properties of the line and plane in the Plücker space,a linear matrix equation was efficiently constructed by combining the Plücker matrices of several coplanar lines so that the line-structured light plane equation could be furtherly solved.The experiments performed validate the proposed method and demonstrate the significant improvement in the calibration accuracy,when the test distance is 1.8 m,the root mean square(RMS)error of the three-dimensional point is within 0.08 mm.

超Grassmannian流形上的超Plücker映射

■表示■-维向量空间中的■-维子空间构成的超Grassmannian流形。本文研究超Grassmannian流形上的超Plücker映射,刻画了■和■上的超Plücker映射的齐次坐标矩阵。

A Line Complex-Based Evolutionary Algorithm for Many-Objective Optimization

In solving many-objective optimization problems(MaO Ps),existing nondominated sorting-based multi-objective evolutionary algorithms suffer from the fast loss of selection pressure.Most candidate solutions become nondominated during the evolutionary process,thus leading to the failure of producing offspring toward Pareto-optimal front with diversity.Can we find a more effective way to select nondominated solutions and resolve this issue?To answer this critical question,this work proposes to evolve solutions through line complex rather than solution points in Euclidean space.First,Plücker coordinates are used to project solution points to line complex composed of position vectors and momentum ones.Besides position vectors of the solution points,momentum vectors are used to extend the comparability of nondominated solutions and enhance selection pressure.Then,a new distance function designed for high-dimensional space is proposed to replace Euclidean distance as a more effective distancebased estimator.Based on them,a novel many-objective evolutionary algorithm(MaOEA)is proposed by integrating a line complex-based environmental selection strategy into the NSGAⅢframework.The proposed algorithm is compared with the state of the art on widely used benchmark problems with up to 15 objectives.Experimental results demonstrate its superior competitiveness in solving MaOPs.

基于Plücker直线的LiDAR点云配准法

高精度的LiDAR点云配准是实现点云数据整体性和保证空间目标三维表面拓扑重建的关键,本文提出了基于Plücker直线的LiDAR点云配准模型,利用Plücker直线表示LiDAR待配准点云与基准点云间的同名直线,根据同名Plücker直线重合的几何拓扑关系,建立Plücker直线共线条件方程,再用最小二乘法确定待配准LiDAR点云与基准点云间的相对位姿参数。结果表明,Plücker直线共线条件配准模型几何约束性较强,配准精度较高。

利用Plücker直线的点云与立体影像配准

现有的基于直线特征的点云与立体影像配准未充分利用直线的几何拓扑关系,针对几何约束强度弱的问题,提出一种基于Plücker直线的配准方法.将点云与立体影像的同名直线用Plücker坐标表示,分别以立体影像的Plücker直线与摄影中心组成的平面作为基本单元,通过同名平面的连续螺旋运动,使同名平面相交于控制直线,构建Plücker直线共面条件方程.实验结果表明,该方法简洁明了,几何约束性强,配准精度高.

基于Plücker直线的机载LiDAR点云与航空影像的配准

机载LiDAR点云与航空影像的配准是地物提取的关键。本文提出了基于Plücker直线的机载LiDAR点云与航空影像的配准模型。基于三维线空间线变换Plücker直线方程,确定点云和影像中的同名直线间的相对位姿关系,建立Plücker直线共面条件方程,通过影像上的Plücker直线在三维线空间中的螺旋运动,实现像点到其对应LiDAR点的坐标变换。结果表明,Plücker直线共面条件配准模型简洁,将旋转和平移统一处理,避免了两者间的耦合误差,提高了配准精度,为获取高质量的地球三维空间信息提供了技术支持。

Plücker Coordinate System of Screws and the Study of Generating Gears

After an introductiou of the Plucker coordinate geometry, a discussion is made of the expression of screws in Plucker coordiuates and the addition of screws’ As a result, the geometry or geuerating gears is re-studied and a formula is derived for calculating the axode leugth or hypoid gears’

PLS算法在激光诱导击穿光谱分析炉渣成分中的应用

炉渣成分的实时在线检测是目前金属冶炼企业迫切需求的一项技术.本文利用激光诱导击穿光谱技术结合偏最小二乘回归模型对炉渣中的CaO、MgO、Al2O3和Fe进行定量分析.采用背景修正和基于等离子体成像强度的谱线归一化法对光谱进行预处理,有效提高了光谱强度的准确性和稳定性.利用25块已知成分的炉渣样品建立偏最小二乘回归定量分析模型,并用其预测另外5块样品成分.CaO、MgO、Al2O3和Fe预测结果的平均相对误差分别为4.7%、11.5%、17.9%和12.5%.实验结果表明,激光诱导击穿光谱结合偏最小二乘回归方法可实现炉渣成分实时在线检测.

基于主成分分析和PLS算法的弧线管污垢特性研究

搭建了弧线管污垢特性实验平台,用于测量相应的污垢参数。基于主成分分析理论和偏最小二乘算法(PLS)建立了弧线管的污垢特性方程。该方程以弧线管的出入口温度、壁温及流速等参数作为模型的自变量,以污垢热阻值作为因变量。利用交叉验证原则以提取最佳主成分个数。通过对预测方程的检验,结果表明:所建5自变量预测方程能较好地实现对弧线管污垢特性的预测,而且明显优于6自变量模型。

Link Budget Design for RF Line-of-Sight via Theoretical Propagation Prediction

Line-of-sight (LOS) link planning condition has been observed to have effects on the atmospheric factor which cause crucial signal loss. The main objective of the planning was to improve a set of a link using point to point condition to assist the performance in emerging its strategy for handling the fixed WLAN service. The purpose of this paper is to provide a quick description of various propagation loss mechanisms on Link Budget Tool (LBT). LBT is customized to create point to point link for local area network (LAN) through radio frequency range operating between 2.400 GHz and 5.800 GHz. This software is able to define the effect of signal loss and expected performances according to the distances between link propagation conditions based on a number of system parameters.

PLS-CADD在输电线路运行维护中的应用

随着我国输电线路数量不断增加,以人工为主的运行维护方式已逐渐无法适应时代要求。基于Li-DAR技术的输电线路管理软件PLS-CADD在输电线路管理方面有其独特的优势。通过LiDAR技术获取的线路走廊三维数据,利用PLS-CADD软件建立输电线路三维模型,计算出不同工况下的线路运行状态,能够实现线路走廊及设备本体的三维浏览、三维测量和危险点的智能检测,分析线路走廊内导线与植被、建筑物、交叉跨越等净空距离,进而确定线路运行状态是否安全,对线路安全性进行有效评估预警,从而安全高效地保障输电线路正常运行,使得线路运维所投入的人力、物力达到最小化。使用该软件对昌门500 kV输电线路进行了线路建模及智能检测,为线路的运行维护提供指导,对该技术的推广具有典型的示范作用。

PLS-CADD相关数据格式转换与工程应用研究

国内主流平断面图绘制软件为SLCAD架空送电线路平断面图处理及定位CAD系统(SLCAD),多数国外业主要求使用PLS-CADD(Power Line Systems-Computer Aided Design and Drafting)绘制平断面图,为提高工作效率,国外输电线路工程需要不同软件间的数据格式转换。文章分析了SLCAD和PLS-CADD两种软件的文件格式,研究并实现了SLCAD向PLS-CADD的数据格式转换,通过国外工程实例验证了其可靠性和高效性。

17集总动力学模型和线性PLS模型在连续重整装置芳烃收率在线预测上的应用

本论文将17集总反应动力学模型和线性回归模型用于在线预测工业级连续重整装置的芳烃收率。首先对17集总模型进行了简化处理从而提高模型计算速度,然后使用偏最小二乘法(PLS)对线性回归模型的参数进行估计,从而提高模型求解精度和稳定性。离线验证结果证明两个模型都是非常适合的。在此基础上,提出了有效的在线预测和在线校正策略,两个模型的在线预测精度分别是0.52wt%(重量百分数)和0.39wt%,与离线模拟精度几乎相当。两个模型可以同时用于在线预测,发挥各自的优势。

基于柬埔寨500kV线路ORG的PLS成图转换方法应用研究

基于柬埔寨500 k V线路,结合SL-CAD软件与PLS-CADD软件格式特点,详细研究了两者格式转换的实现方法,在VS环境下编写ORG-PLS程序实现SL-CAD平台到PLS-CADD平台的转换。转换程序的实现,解决了国内设计人员使用PLS-CADD不熟练的弊端,满足设计在ORG平台开展计算与排位,在PLS-CADD平台校验、出图的要求,避免了因人工编辑而出现的差错,大大提高了勘测设计的工作效率,实现了国内输电线路测量数据处理软件与国际主流线路排位软件的衔接。

近红外光谱技术应用于利福昔明混悬剂的定量分析

为利福昔明混悬液建立一种快速有效的定量分析方法,按处方配制9组共54个模拟样本,挑选其中5组作为训练集,其余4组作为预示集,采集各样本的近红外光谱数据,利用多元线性回归法及PLS法对数据进行处理。结果显示,模拟样本中对主药利福昔明采用多元线性回归法,加样平均回收率为291.8%,RSD为65%,采用PLS法的加样平均回收率为100.1%,RSD为1.6%,说明近红外光谱结合PLS应用于利福昔明混悬液的定量分析是可行有效的。

Closed form of the inverse Plücker correspondence in line geometry

By mapping the homogeneous coordinates of two points in space to the Plücker coordinates of the line they determine, any transformation of type SL(4) upon points in space is mapped to a transformation of type SO0(3, 3), the latter being the connected component containing the identity of the special orthogonal transformation group of the linear space spanned by Plücker coordinates. This is the classical Plücker correspondence, two-to-one and onto. It has important applications in line geometry and projective transformations.While the explicit form of Plücker correspondence is trivial to present, its inverse in explicit form, which is also important in application, is not found in the literature. In this paper, we present a simple and unified formula for the inverse of the Plücker correspondence.

直线特征约束下利用Plücker坐标描述的LiDAR点云无初值配准方法

经典的基于点状特征匹配的地面激光雷达（light detection and ranging,LiDAR）点云配准算法实现过程中,点状特征的提取精度对算法运行结果的影响通常较大;基于迭代运算的LiDAR点云配准算法计算量大,对未知参数的初值依赖程度较高,在求解大转角刚体变换参数时算法不稳定。对此,提出了一种线状特征约束下基于Plücker直线坐标描述的LiDAR点云配准算法。立足于经典的向量代数与对偶四元数的相关理论与方法,分析并确定了Plücker直线坐标与对偶四元数之间的相互转换关系以及模型描述方法;以LiDAR点云配准前后同名线状特征的Plücker直线坐标相等为约束条件,构建了线状特征约束下基于Plücker直线坐标描述的刚体变换模型;立足于最小二乘基本准则,通过目标函数的极值化分析实现了线状特征约束下地面LiDAR点云配准参数的直接求解。实验结果表明,所构建的基于Plücker直线坐标描述的地面LiDAR点云配准模型,无需事先确定变换参数的初值,避免了多元函数的线性化过程,解除了参数结果对于迭代初值的依赖,理论上克服了迭代法在求解大转角相似变换参数时的算法不稳定问题。此外,较之单纯基于点状特征匹配的LiDAR点云配准算法,该算法可以有效地增强LiDAR点云配准过程的约束,达到提高配准质量的目的。

近红外光谱法快速测定三七总皂苷的方法研究

以中药为实例 ,提出用近红外光谱技术快速检测复杂物质分析体系中有效组分 .在 0 .133%～ 7.0 4 0 %浓度内 ,根据三七总皂苷在 75 0 0～ 4 0 0 0 cm- 1 的近红外吸收光谱 ,利用光纤远程传输技术 ,采用偏最小二乘算法建立校正模型 ,建立了在三七药材提取物中定量检测该物质的新方法 .交叉检验的最佳主因子数为 4 ,相关系数 R2 为99.4 3% ,交叉验证均方差为 0 .15 9% .该方法快速、准确、简便 ,适合于中药工业过程在线检测 .

非视距传播环境下对移动用户定位的AOA方法

非视距传播问题是移动定位中的一个关键问题.基于几何结构的单次反射统计信道模型,提出了一种减小非视距传播影响的AOA定位方法.该方法一方面利用所有的参数信息进行定位,使有限的资源得到充分利用,另一方面采用不等式约束减小移动台的可行区域,二者结合以提高非视距传播环境下的定位精度.仿真结果证明了该方法的有效性.

一种有效减小非视距传播影响的TOA定位方法

本文基于移动通信环境中非视距 (NLOS)传播时延服从指数分布的特性 ,提出了一种有效减小NLOS影响的定位方法 .该方法首先利用测量的波达时间 (TOA)和NLOS传播时延的统计特性估计由NLOS引起的附加时延 ;然后从测量的波达时间中减去附加时延 ,得到对LOS传播时间的估计 ,进而估计移动台的位置 ;最后 ,对不同时刻估计的移动台位置进行平滑处理 ,进一步减小NLOS的影响 .采用该方法对移动台的位置进行的估计是一种无偏估计 ,不需要增加系统成本 ,计算简单 ,是一种非常实用的定位方法 .仿真结果证明了该方法的有效性 .