基于测量数据的植物建模

测量数据,即图像和激光扫描数据,是建模真实植物的可靠依据.然而,由于植物结构复杂、自遮挡严重,相机或激光扫描仪只能感知部分可靠数据且扫描数据中噪声较多,导致从该类数据恢复植物模型极为困难.文中提出通过检测尖点特征,如带叶片植物的叶尖以及纯枝干植物的枝稍,重建植物模型的方法.该方法能够从多视点图像中便捷重建带叶片植物模型,从含噪声激光数据中重建不带叶片的纯枝干模型.实验证实了所提特征检测算法的正确性以及植物重建算法的有效性.     

基于SketchUp的建筑物实景三维模型重建

随着三维激光扫描仪的价格不断下降,激光扫描技术的不断完善和数据处理方法的不断提升,三维激光扫描技术应用越来越广泛。本文通过STONEX X500Plus三维激光扫描仪采集传习馆点云数据,利用SketchUp软件,详细介绍建筑物三维建模的主要技术流程,实现建筑物点云数据实景三维建模。     

基于QT的机载三维激光扫描仪软件系统设计

随着测绘技术的发展,利用机载三维激光扫描仪获取点云数据,从点云数据中提取模型信息成为现代测绘技术的一种发展趋势. 点云数据处理的相关应用也越来越多,点云数据的处理软件参差不齐,需求和功能也各不相同. 针对上述问题,在基于QT编程平台下,利用PCL开发机载三维激光扫描仪点云数据处理软件,集中处理点云数据. 该系统由点云数据读写、三维显示、点云滤波、网格重构、点拾取、点云分割及NARF关键点提取等功能模块组成. 各模块采用面向对象的思想设计,功能易于扩展,以完成进一步的测绘工作. 实践表明,该系统具有良好的工程实用价值,可以快速完成机载三维激光扫描仪的数据处理工作.     

应用于三维点云数据去噪的改进C均值算法

针对三维激光扫描仪采集到的点云数据中离群点不易区分和去噪难度大的问题,提出了一种改进的C均值算法。通过分析三维点云数据特征,在传统C均值算法中引入模糊聚类权重因子,降低类内距离和拉大类间距离,有效增强了离群点特征以降低识别难度。进而将识别出的噪声分类别处理,利用改进的C均值算法去除大尺度噪声,构造双边滤波算法去除小尺度噪声数据。与密度聚类算法、正交整体最小二乘平面拟合和基于特征选择的双边滤波点云去噪等算法相比,去噪准确度分别提升了7.3%、6.5%和6.0%,实验结果表明该算法可以有效去除大尺度噪声并能较好地保留有效数据。     

数据预处理技术在劳动保障信息系统中的应用

数据挖掘是一种知识发现技术,近年来得到了快速的发展。数据预处理是数据挖掘过程中的一个重要步骤,尤其是在对包含有噪声、空缺,甚至是不一致数据进行数据挖掘时,更需要进行数据的预处理,以提高数据挖掘对象的质量,并最终达到提高数据挖掘所获模式知识质量的目的。本文讨论了在劳动保障数据挖掘工作中,如何应用数据预处理技术。     

地面三维激光扫描点云数据处理及建模

本论文以昆明理工大学呈贡校区“昆明理工大学”石碑作为目标场景,利用地面三维激光扫描仪Maptek I-Site 8200SR获取目标场景的点云数据,使用Maptek I-Site Studio 6.0对点云数据进行预处理,包括点云数据的配准、去噪及精简;通过提取特征点云同时结合AutoCAD2014、3ds Max实现对目标场景的建模。研究三维激光扫描点云数据预处理的方法步骤及模型构建过程,通过分析数据处理及建模结果,结合当前的研究状况探讨了模型的相关应用,并展望进一步的研究方向以及工作内容。     

基于多传感器融合的车载三维测量系统时空配准

在车载三维测量系统中,为了快速、实时、完整地获取数字城市中所需要的三维空间信息,集成了全球定位系统(GPS)、激光扫描仪(LS)等多种传感器,其中,数据的处理应用了多传感器数据融合原理。各传感器间的空间配准和时间配准是多传感器数据信息有效融合的关键。通过解算各传感器坐标系间关系和利用激光扫描仪的时间记录功能、GPS时间打标功能解决了空间配准和时间配准问题,成功地应用于"近景目标三维测量技术",取得了预期的效果,并给出了实验结果。     

激光光斑中心精确定位算法研究

研究激光光斑精确定位问题,传统的亚像素定位算法,面临抗干扰能力弱、定位精度低和软件实现复杂等问题.为了满足变形测量系统中对激光光斑中心精确定位的要求,提出了基于重心的曲线拟合亚像素定位算法.在重心法的基础上,引人了曲线拟合算法来提高激光光斑中心定位的精度.由于加人了图像预处理环节,有效的降低了噪声干扰,增强了算法的抗噪声性能.算法仅对图像中少量的数据点进行计算,不但语言描述简单,而且能大大节省系统资源.仿真结果表明算法是一种实用的精确定位算法,提高变形测量系统的精度要求.     

三维激光扫描仪分辨率的测试方法

为获取便携式三维激光扫描仪分辨率与扫描范围间的量化关系,以Creaform公司的Handyscan EXAscan扫描仪获取标准块在不同分辨率等级下的点云数据,应用逆向校核软件Geomagic Qualify测试试验数据样本,并采用方差分析和加权平均的统计方法分析样本数据。试验结果显示,EXAscan扫描仪的四级分辨率与扫描范围间均呈线性关系,且拟合度均超过0.979,该测试方法可快速有效地判别三维激光扫描仪的分辨率水平。     

基于模糊增强的激光大气传输光斑预处理算法

介绍了激光大气传输测量基本模型,对激光大气传输特性测量过程中引入的噪声进行分析,分析了传统模糊增强算法特点及其不足,针对不足进行隶属度函数改进,提出了利用均值滤波和改进的模糊增强进行激光大气传输光斑预处理算法,并利用该算法对实验中的图像进行处理,结果表明,相比于常见激光图像预处理算法,该算法可以有效增强图像对比度,改善图像质量.     

Laser-scanning vibrometry for ultrasonic transducer development

A laser-scanning vibrometer can be used for measuring even the smallest motions of the active area of ultrasonic transducers. Additionally, a new method for measuring and visualising the acoustic sound waves, emitted from such transducers, is developed. The new method, too, is based on laser-scanning vibrometry and allows the contact-less measurement of ultrasound fields with high spatial resolution. The combination of both techniques permits to analyse and optimise the acoustic behaviour of ultrasonic transducers. Moreover, the method is qualified for investigating and presenting numerous acoustic phenomena.     

Visualizing soil surfaces and crop residues

A test case for visualizing field and laboratory data pertaining to soil erosion and infiltration is examined. Several visualization techniques were used to derive image data from an experiment in which the effect of a sequence of five rainfalls on a laboratory-formed soil surface was measured. The base data are millimeter-resolution elevation models generated using a laser-scanning device. The surfaces generated by the laser scanner are visualized as perspective views. Changes in the soil surface with cumulative rainfall are examined by visualizing differences between successive laser-scanned surfaces. The modeling of straw coverage, which can influence infiltration, overland flow, and erosion, using a random process model is discussed     

Automated inspection planning of free-form shape parts by laser scanning

The inspection operation accounts for a large portion of manufacturing lead time, and its importance in quality control cannot be overemphasized. In recent years, due to the development of laser technology, the accuracy of laser scanners has been improved significantly so that they can be used in a production environment. They are noncontact-type-measuring devices and usually have the scanning speed that is 50–100 times faster than that of coordinate measuring machines. This laser-scanning technology provides us a platform that enables us to perform a 100% inspection of complicated shape parts. This research proposes algorithms that lead to the automation of laser scanner-based inspection operations. The proposed algorithms consist of three steps: firstly, all possible accessible directions at each sampled point on a part surface are generated considering constraints existing in a laser scanning operation. The constraints include satisfying the view angle, the depth of view, checking interference with a part, and avoiding collision with the probe. Secondly, the number of scans and the most desired direction for each scan are calculated. Finally, the scan path that gives the minimum scan time is generated. The proposed algorithms are applied to sample parts and the results are discussed.     

基于激光扫描的储矿场散装物料计量系统

针对目前国内大型储矿场盘矿管理的实际情况,设计了一套基于激光扫描的散装物料计量系统。系统采用高精度的双激光测头对堆体进行高速连续扫描,通过建立数学模型实现矿堆的截面积计算进而积分得到堆体体积,此外还详细阐述了该系统的测量原理、方法及硬件软件结构,应用结果表明该系统测量速度快、精度高,市场应用前景十分广阔。     

地学数据标注和引用现状与存在的问题初探

科学数据引用是近年来逐渐兴起与成熟的一个领域,世界各国都对其进行了一系列相关工作。地学作为一门涉及范围极广的科学,在众多科研工作中积累了大量的科学数据。概述了我国科学数据共享体系的现状与存在的问题,以寒区旱区科学数据中心提供的数据施引文献库为例,分析了该中心数据集自2006~2013年(注:2013年数据不全)的被引情况。研究结果发现:科学数据集自公开到被广泛引用需要约2年的时间积累,2年之后被引情况大幅度增长。该数据集遥感数据最多,其次是土地和气象数据。但从被引情况来看,以遥感和气象被引次数居首,说明用户对此类数据的需求较大。     

GML 3.0应用模式的开发及应用研究

简单介绍了GML3．0,然后详细阐述了GML3．0的主要模式;论述了GML应用模式开发的若干技术问题;最后提出了基于GML的城市道路网络模型,并实现了基于GML的空间数据转换引擎。     

江苏省市际断面水文监测系统设计与研究

为实现水利工程联合运行、水污染联合防控探索,推进跨区域水生态补偿,形成河湖水环境治理良性发展机制,江苏省市际断面水文监测系统项目应运而生。采用水文现状调查与信息研究相结合的方法,设计基础设施、数据资源、应用支撑、业务应用 4 个层面,以及信息安全和标准规范两大体系的总体框架,分析基于数据汇聚平台与实验室数据资源的数据资源层、应用支撑层、业务应用层的主要建设内容,从而构建省域、市域、县域边界重要河段水量水质统一监测与监控系统。江苏省市际断面水文监测系统的设计与研究,不仅为江苏省流域的精密监测、精细管理、精准调度提供有力支持,也为省内外类似水文监测系统建设提供参考和借鉴。     

On the use of construct reliability in MIS research: a meta-analysis

This paper reports results of a meta-analysis of construct reliability measures reported in MIS research. Based on 418 measures from 63 articles published in four major journals, it is observed that although scales developed more recently are no more reliable than those developed in the 1980s, the reliability of most scales reported in the literature is above generally accepted levels. However, for scales used in basic research, more than 40% of them had a reliability lower than the minimal acceptable level, at least 0.80. Scales using interviews for data collection; with more items, obtained from previous studies; and generated from both literature review and interview, were found to have higher reliability. Other research design characteristics, including sample size, type of subjects, scale type, scale format and number of scale points, were found to be insignificant in affecting reliability. Implications of the findings are discussed and guidelines for researchers on the design of their research methodologies with respect to having scales with the level of reliability suitable for the types of research at hand are provided.     

Preliminary guidelines for empirical research in software engineering

Empirical software engineering research needs research guidelines to improve the research and reporting processes. We propose a preliminary set of research guidelines aimed at stimulating discussion among software researchers. They are based on a review of research guidelines developed for medical researchers and on our own experience in doing and reviewing software engineering research. The guidelines are intended to assist researchers, reviewers, and meta-analysts in designing, conducting, and evaluating empirical studies. Editorial boards of software engineering journals may wish to use our recommendations as a basis for developing guidelines for reviewers and for framing policies for dealing with the design, data collection, and analysis and reporting of empirical studies.