3维不规则空间对象的求交和距离运算及其在矿山透水性分析中的应用

讨论了3维不规则空间对象和栅格集合的求交运算和距离运算的概念及其数学描述方法,设计了相应的算法,并分析了这些运算在矿山透水性分析中的应用方式和应用步骤.     

3维不规则空间对象的求交和距离运算其在矿山透水性分析中的应用

讨论了３维不规则空间对象和栅格集合的求交运算和距离运算的概念及其数学描述方法,设计了相应的算法,并分析了这些运算在矿山透水性分析中的应用方式和应用步骤。     

应用延迟累加的微弱GPS信号捕获算法

针对在弱信号环境下传统算法无法进行捕获的问题,提出了一种改进算法。该算法在双块零拓展(double block zero padding,DBZP)算法的基础上,采用延迟累加的方法,首先将DBZP算法相关运算结果中被舍弃的部分暂存,然后对延迟1ms的接收信号进行相关运算,得到相应的相关运算结果,将其与存储的运算结果进行相干累加,并将相干累加结果作为捕获模块输出与门限值进行比较。改进算法在增加极少运算量的前提下,通过提高相关运算结果的利用率,增加了数据观测量。仿真结果表明,改进算法能够提高捕获算法处理增益,在捕获载噪比为17dB-Hz的信号时,检测概率能够达到91%。     

疏浚中基于Matlab的土方量计算方法

通过比较疏浚测量中计算土方量所采用的平均水深方法和不规则三角网法,结合工程实例,提出了一种基于插值运算的软件算法,并对三者进行了对比分析,得出程序算法在疏浚测量计算土方量工作中的特点和优势。     

矢量地形图要素边线直角化方法研究

针对矢量地形图数据中要素边线直角化问题,分析了最小二乘法的优缺点,提出了最小二乘法以外的一种新的解决方案--边线中点固定算法,该方法的优势在于算法模型简洁、运算速度快,适用于大数据量的处理和运算。本文详细描述了该解决方案的实现过程,并分析了其存在的不足和适用范围。     

基于谱运算的复相关函数法在干涉复图像配准中的应用

复图像配准是干涉SAR处理中的关键步骤之一,要求配准精度达到0.1个像元的水平,而控制点的精确定位是复图像配准中的核心环节.尽管前人提出采用复相关系数法、信噪比法、平均扰动函数法等算法,但他们都是基于滑动窗口的算法,运算效率低.在分析前人算法的基础上,引入基于谱运算的复相关函数算法实现控制点的亚像元级精确定位,分析比较了算法的计算复杂度.应用该算法对我国某地区ERS-2的SLC数据进行了实验,生成了干涉图像,并进行了相干性分析,证明了该算法的可行性和稳健性.实验研究证明即使在主从图像时间间隔较大、相干性差的情况下,应用该算法也能获得干涉条纹图.     

统计费用网络流相位解缠并行处理

针对雷达干涉测量(InSAR)相位解缠中的单机计算资源不足和相对运算效率不高的问题,提出了数据并行处理策略。以统计费用网络流相位解缠为例,分析了该算法的数据划分方法,构建了并行运算实验系统,实现了统计费用网络流相位解缠并行处理,并从解缠效果、内存使用量和运算效率3个方面对实验结果进行了分析。     

基于形态学重构运算的地面目标识别算法

针对在热红外遥感图像上识别背景复杂的地面目标较为困难这一问题,提出了基于形态学重构运算的地面目标识别算法。该算法首先对形态学重构运算的背景抑制原理及其算法的适应性进行了分析,并将该算法应用于对原始图像的背景抑制与处理;然后,对处理后的图像进行分割,获得感兴趣的目标区域;最后,通过对感兴趣区域特征的提取与匹配识别目标。实验结果表明,该方法能从复杂自然场景中有效地识别出目标。     

遥感图像栅格—2DRE四叉树结构变换算法

本文提出并分析了一个栅格—四叉树结构间的变换算法。栅格和四叉树这两种结构各适用于某些特定的运算,各有其优、缺点,能够互相补充。栅格结构是最常见的图像数据结构,而四又树是近年来才得到广泛的注意和应用,从而有了很大发展的一种新的数据结构。在本文中,简述了四叉树的发展,并对变换算法的基础及算法作了详细的阐述,进而对其进行了评价和分析。     

提高星载GPS接收机RAIM算法运行效率的方法研究

文中分析最小二乘残差方法和奇偶空间方法的原理和方法,分别针对两种方法中的故障检测统计量构造、可用性判断、故障检测与故障识别等4个模块的运算量进行比较。提出一种基于最小二乘方法构造检测统计量的奇偶空间改进方法,该方法能够提高RAIM算法运算效率,并利用工程样机对算法进行实际验证。试验结果,表明在满负荷运算的情况下,即在导航星数目为12颗时,改进算法的运行时间仅为24.8 ms,相比最小二乘残差方法和奇偶空间方法运行时间分别减少64 ms和10 ms,运算效率更高,更加适合星载GPS接收机使用。     

Efficiency Evaluating of Automatic Lineament Extraction by Means of Remote Sensing (Case Study: Venarch,Iran)

One of the main geological evidence for many ore-bearing deposits and mineralized regions is the existence of points in highly fractured zones and the fragmentation intensity resulted from development of hydrothermal alteration along the fractures, the process leading to the occurrence of ore deposits. In this paper, a new algorithm has been proposed including a set of image processing techniques for detection the lineaments in satellite images by means of programming in MATLAB environment. The set of utilized methods includes line segment extraction by EDLine algorithm, merging line segments by Tavares method and linking the resulting line segments based on the collinearity and proximity criterion. The tectonic structures were stabilized by B-Spline curve fitting. The proposed algorithms were implemented on the ASTER image of a structurally multiple fractured region located in the central Iran, and the lineament map of Venarch area has been depicted. The results obtained from the proposed algorithms indicate a high accuracy of the operations detection of 80% for the reference map lineaments and the overall accuracy of the method is effectively reported as 62%. Combination of the above algorithms proposes a new method that precisely resulted in obtaining image processing of geological evidence for increasing the accuracy and decreasing the risk, before any field operations.     

A New Method of Applying Polygon Boolean Operations Based on Trapezoidal Decomposition

Boolean operations between planar polygons are fundamental operations in the GISciences. In this paper, a new algorithm based on trapezoidal decomposition is used to perform Boolean operations. Using this method, Boolean operations between polygons are transformed into Boolean operations between decomposed trapezoids. It is comparatively easier to process the simple trapezoids than arbitrary polygons. This new method avoids the complex computation of the spatial relationship between the polygons' edges in the traditional algorithms, thus making the procedure more efficient and easier to understand. In addition, the proposed algorithm can work with concave polygons and those with holes.     

非线性最小残差绝对值和最小平差的遗传算法

遗传算法是一种基于自然选择和自然遗传学机理的全局优化搜索算法。文章在扼要介绍遗传算法的基础上,设计了非线性残差绝对值和最小的遗传算法,并将其运用于非线性残差绝对值和最小的平差模型中,并通过实例验证了该算法的有效性。     

孔径为4的全球六边形格网系统索引方法

从集合论的角度描述基于正八面体的、孔径为4的六边形格网系统,通过对偶、中心剖分两项基本操作建立不同层次六边形格网集合与三角形格网集合之间的递推、包含和层次关系。定义三轴整数格网坐标系描述三角面上六边形格网单元的位置,通过若干定理解决了格网索引的核心问题,如单元笛卡尔坐标的计算,邻近、孩子、父亲单元的判定。据此设计了单元索引算法并通过对比实验进行验证。实验结果表明,本文提出索引算法的平均执行效率约是同类算法的600倍,因而更适合计算机处理。     

SIMD correlator library for GNSS software receivers

Software receivers have had a discernable impact on the GNSS research community. Often such receivers are implemented in a compiled programming language, such as C or C++. A software receiver must emulate the digital signal processing (DSP) algorithms executed on dedicated hardware in a traditional receiver. The DSP algorithms, most notably correlation, have a high computational cost; this burden precludes many software receivers from running in real time. However, the computational cost can be lessened by utilizing single instruction multiple data (SIMD) operations found on modern ×86 processors. The following demonstrates how C/C++ compatible code can be written to directly utilize the SIMD instructions. First, an analysis is carried out to demonstrate why real time operation is not possible when using traditional C/C++ code is carried out. Secondly a tutorial outlines how to write and insert ×86 assembly, with SIMD operations, into C/C++ code. Performance gains achieved via SIMD operations are then demonstrated, and pseudo code outlines how SIMD operations can be employed to perform correlation. Finally, a C/C++ compatible SIMD enabled arithmetic library is added to the GPS Toolbox for use in software receivers.     

遗传算法及其在图像阈值选取中的应用

论述了遗传算法的基本原理、操作和特点,并以图像阈值选取中的最大类间方差法为例,给出用遗传算法优化图像阈值选取的步骤和方法,实验结果表明了这一方法的有效性。     

MATLAB Algorithm Availability Simulation Tool

This paper describes a set of MATLAB functions currently being developed for Space Based Augmentation System (SBAS) availability analysis. This toolset includes simulation algorithms that are constantly being developed and updated by various working groups. This set of functions is intended for use as a fast, accurate, and highly customizable experimental test bed for algorithm development. A user-friendly interface has also been developed for the tool. It is open source and can be downloaded from the Stanford GPS Research Laboratory web site (). Therefore, it provides a common ground for different working groups to compare their results. This paper demonstrates the utility of this toolset by analyzing the SBAS service volume models for the Conterminous United States. The paper describes the functionality provided within the software, and shows an example set of contour plots which are the means for investigating how different algorithms and parameters impact availability.     

1∶250000水系要素综合缩编技术方法

针对国家空间数据基础设施建设的需求,本文介绍了适应于不同空间特征水系的河流选取、湖泊合并、毗邻等基本综合操作,并提取水系综合相关算法和技术思想,结合地形数据的基本特点及应用需求,给出了一套可行的1∶250 000水系综合实施策略。所研究的成果可应用于小比例尺地形数据的综合生产任务。     

基于C＋＋类的快速实现测量数据数值计算的方法研究

采用面向对象的程序设计思想,基于C＋＋语言实现了矩阵类,避免了用二维数组来处理矩阵运算时遇到的大量繁琐问题。同时,在矩阵类的基础上实现了线性方程组类,对几种常用的求解线性方程组的算法进行了封装,便于进行频繁的调用。     

格网DEM坡度计算模型的相似性研究

当DEM的精度和分辨率确定后,坡度坡向计算结果取决于计算模型。本文设计了逐栅格单元的相对差等级评价方法,并结合基于整体的频率图和XY散点图评价指标,定量揭示了坡度计算模型之间的异同。主要结论为:①坡度计算模型有离散和连续之分,连续型模型能给出更加符合实际的坡度坡向计算结果;②坡度计算结果与计算点数有关,点数越多,计算结果越稳定;③算法间的差异随DEM分辨率的增大而增大。最后本文给出了实际应用中的坡度计算模型。