基于地面三维激光扫描数据的快速建模

三维激光扫描技术具有速度快、精度高、自动化程度高并且不与物体直接接触等诸多优点,现已应用于古建筑保护、数字城市、工业生产、地形测绘等不同领域。本文利用地面三维激光扫描仪对校内樱花园手形建筑物进行扫描,获取该目标物的点云数据,并对获取的点云数据进行拼接、去噪处理。同时,利用点云数据处理软件Geomagic对目标物进行快速的三维模型重建并达到了预期的效果。     

基于地面三维激光扫描仪的塔式建筑物变形监测研究

针对传统变形监测手段面对高大的塔式建筑物时观测困难的问题,以云南大学呈贡校区塔式建筑物为研究对象,采用Leica P40地面三维激光扫描仪对其进行两期三维点云数据采集,经点云数据绝对定向、拼接与融合等数据处理后,构建两期点云数据模型,对两期数据进行模型拟合与点位差异分析.结果表明:该塔式建筑物整体未发生明显水平位移与沉降,墙体表面存在脱落可能.该结论表明基于地面三维激光扫描仪的高塔建筑物形变分析可行.     

基于回光强度的地面三维激光扫描仪测距误差模型

地面三维激光扫描仪是一种新型测量仪器,其核心优势是非接触、速度快、精度高,应用领域非常广泛,而使用之前的设备检校极为重要。影响地面三维激光扫描仪测距精度的因素很多,本文的研究以地面三维激光扫描仪测距原理及误差来源为基础,提出一种稳健的曲线拟合算法对点云数据进行处理,建立了基于回光反射强度的地面三维激光扫描仪测距误差模型,经实验验证取得了良好效果。     

基于三维激光扫描仪的校园建筑物建模研究

三维激光扫描仪可以连续、自动、快速获取目标物表面的采样点数据。论述三维激光扫描仪工作原理、数据处理流程。以校园建筑物为例,给出三维数据获取、数据处理、模型建立的基本方法和结果。探讨采用点云数据进行数字校园的方法。     

人物雕塑模型三维表面建模方法探究

三维激光扫描是一种通过激光测距方式实现三维物体表面空间数据获取的技术。本文介绍了一种利用三维激光扫描技术并结合相应软件对人物雕塑模型三维表面进行重建的方法。该方法通过三维激光扫描仪获取目标模型表面精确的点云数据,在对点云粗拼接的基础上进行精确拼接,以三角网的形式重构雕塑表面,并结合逆向软件进行纹理映射及其接缝处理以实现3D模型表面重建。结果表明,利用该方法可以实现对人物雕塑模型3D表面的快速有效重建。     

浅谈机载激光雷达数据处理

机载激光雷达是激光探测及测距系统,它集成了GPS、IMU、激光扫描仪。其中主动传感系统(激光扫描仪)利用返回的脉冲可获取探测目标高分辨率的距离、坡度、粗糙度和反射率等信息,而被动光电成像技术可获取探测目标的数字成像信息,经过地面的信息处理而生成逐个地面采样点的三维坐标,最后经过综合处理而得到沿一定条带的地面区域三维定位与成像结果。     

基于Cyclone和PolyWorks的三维建模实现

从数据采集到数据处理,再到最后的模型重建,以实例详细介绍了地面激光扫描三维建模的整个流程。利用LeicaHDS6000地面激光扫描仪进行点云数据采集,针对规则和不规则建筑物的特点,分别基于Cyclone和PolyWorks软件实现了三维建模。     

基于三维激光扫描的校园建筑物三维建模研究

"数字校园"建设是科技发展的必然趋势,为加快这一进程,本次研究将地面三维激光扫描技术应用到大学校园。本文以Z+F IM AGER 5010c地面三维激光扫描仪采集到的吉林建筑大学基础实验楼数据为基础,运用3ds max、Auto CAD、Point Cloud等建模软件建立三维模型。同时将依据点云数据建立的实体模型与实际测量数据进行对比和精度分析,验证了地面三维激光扫描仪在建筑物三维模型建立中的精度和可靠性。     

结合机载和地面LiDAR数据的建筑物重建技术

机载LiDAR数据虽然能够快速地获取建筑的顶面信息,但是不能够有效地获取建筑物的侧面信息。地面三维激光扫描仪能够有效地获取建筑物的立面信息,但获取建筑的顶面信息较困难。针对机载和地面LiDAR数据在精细建模中存在的问题,采用机载地面LiDAR数据相结合的方式对建筑物进行精细的建模,实验结果表明,采用该法能够实现建筑物的精细建模。     

无人机影像点云与地面激光点云配准的三维建模方法

地面激光扫描仪(Terrestrial Laser Scanner,TLS)能够快速地获取高大建筑物侧面点云数据,但较难获取其顶部点云数据。无人机(unmanned aerial vehicles,UAV)通过搭载五镜头倾斜摄影相机,能在短时间内获取高大建筑物的顶部影像,并基于摄影测量原理生成建筑物顶部的三维点云。文中针对高大建筑物的三维建模,首先通过UAV影像构建三维点云信息,然后将UVA影像点云与TLS点云数据进行配准后构建其三维模型。以云南师范大学呈贡校区武之楼为例,分别采用单一源的两种数据进行三维建模,并与两种配准后的数据进行三维建模作比较,实例结果表明,配准后的数据建模更完整,效果更好,能更完整地表现出建筑物的信息。     

阿克苏河-塔里木河水系水质污染遥感监测与评价

 采用Landsat TM数据分析了阿克苏河—塔里木河断面水质污染状况,通过波段的DN值和常规监测数据建立能反映水质状况的 污染物监测模型。结果发现,将2000年常规监测数据代入模型后,与遥感数据的结果基本吻合| 重建阿克苏河—塔里木河的连续水体 污染变化曲线,得出污染物浓度随着远离上游而增加。     

Monitoring drought dynamics in the Aravalli region (India) using different indices based on ground and remote sensing data

The hard-rock hilly Aravalli terrain of Rajasthan province of India suffers with frequent drought due to poor and delayed monsoon, abnormally high summer-temperature and insufficient water resources. In the present study, detailed analysis of meteorological and hydrological data of the Aravalli region has been carried out for the years 1984–2003. Standardised Precipitation Index (SPI) has been used to quantify the precipitation deficit. Standardised Water-Level Index (SWI) has been developed to assess ground-water recharge-deficit. Vegetative drought indices like Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) and Vegetation Health Index (VHI) have been computed using NDVI values obtained from Global Vegetation Index (GVI) and thermal channel data of NOAA AVHRR satellite. Detailed analyses of spatial and temporal drought dynamics during monsoon and non-monsoon seasons have been carried out through drought index maps generated in Geographic Information Systems (GIS) environment. Analysis and interpretation of these maps reveal that negative SPI anomalies not always correspond to drought. In the Aravalli region, aquifer-stress shifts its position time to time, and in certain pockets it is more frequent. In comparison to hydrological stress, vegetative stress in the Aravalli region is found to be slower to begin but quicker to withdraw.     

使用FME与VBA提取机场方格网高程数据

因受机场工程设计软件的测量数据容量限制,基于LiDAR采集、点云分类后得到的地面点云数据LAS不能完整应用于目前设计软件进行设计计算。本文通过对拟选技术方案的筛选,提出了利用FME Workbench数据处理功能,结合VBA编程获取外部方格网平面数据的方法。该方法在FME Workbench中实现了地面点云数据构建TIN、采用逐点内插方法从TIN中提取方格网高程数据、等高线生成及相应图形处理与成果输出。最终通过实际算例证明了该方法的有效性。     

Landslide risk analysis between Giri and Tons Rivers in Himachal Himalaya (India)

The area around Sataun in the Sirmur district of Himachal Pradesh, India (falling between the rivers Giri and Tons; both tributaries of the Yamuna River) was studied for landslide vulnerability on behalf of the inhabitants. The study was made using extensive remote sensing data (satellite and airborne). It is well supported by field evidence, demographic and infrastructural details and aided by Geographic Information System (GIS) based techniques. Field observations testify that slope, aspect, geology, tectonic planes, drainage, and land use all influence landslides in the region. These parameters were taken into consideration using the statistical approach of landslide hazard zonation. Using the census data of 1991, vulnerability of the populace to the landslide hazard was accessed. As most of the infrastructure in the region is concentrated around population centres, population data alone was used for vulnerability studies.     

Gravity Changes Before Large Earthquakes in China: 1998-2005

Although it is well known that coseismic gravity changes take place during an earthquake, previous research has not yielded convincing evidence demonstrating that significant gravity changes occur before large earthquakes. Furthermore, even if we suspect that gravity changes occur before large earthquakes, we have yet to demonstrate how to consistently observe these changes for useful earthquake forecast that would bring benefits to society. We analyzed ground gravity survey data obtained in 1998, 2000, 200...     

GNSS系统及其技术的发展研究

阐述了国际上卫星导航系统的总体发展,对美、俄、欧、中的四大全球系统,以及相关的区域系统和增强系统进行了简单的介绍,研究分析了GNSS系统及其技术的发展趋势,同时分析了我国Compass全球系统面临的机遇和挑战,并提出了我国未来工作的建议.     

“4D”技术及其应用

介绍“４Ｄ”（即数字地面模型、数字正射影像、数字栅格地图和数字线划地图）系列产品的生产流程、关键技术、及其在耕地保护、防灾减灾救灾和城市规划等方面的应用方法。     

Virtual Australia: its key elements – know,think, communicate

Abstract

Virtual Australia is not a well-defined or agreed concept. This discussion paper conceptualises Virtual Australia as a ‘virtual [digital] model containing and representing all non-trivial objects and their contextual environment – from blue sky to bedrock – in real world Australia’. It describes a scenario for Virtual Australia, one or two decades from now, in which the locations and conditions of non-trivial objects and their environment are updated automatically through a combination of remote sensing and wireless communication technologies in support of a ‘Supranet’. It then examines the concept of the ‘Supranet’ – a pervasive information network based largely on wireless technology linking the physical world to a virtual model in real time – and develops and discusses three principal characteristics of the Supranet: the ability to have or collect specific information (know); the ability to process information (think); and the ability to communicate that information. If, in the near future, any or all non-trivial devices are to some extent able to know, think and communicate, the potential for object autonomy will be realised.     

自动车辆定位导航系统中传感器的误差分析

对国界定位导航系统中几种常见的辅助传感器所产生的误差进行了分析，导出了不同传感器的误差模型。这些误差模型是估计车辆位置的扩展卡尔曼滤波器的基础，同时也为选择适当的传感器提供了理论根据。