基于粗DEM的立体SAR像对配准

影像配准是雷达立体摄影测量技术获取数字高程模型的一个关键步骤,也是一大难点。为了能够自动而又稳健地获取高精度的立体SAR像对配准结果,文中设计一种基于粗DEM、距离多普勒SAR构像模型和基于区域逐级窗口的立体SAR像对配准方法。该方法采用距离多普勒SAR成像模型和粗DEM获取像素级的粗略配准结果。在此基础上,采用基于区域的逐级窗口配准方法获取高精度的配准结果。文中最后利用立体SAR像对进行实验研究。实验结果表明,设计的立体像对配准方法可行,其配准精度可以达到子像素级,距离向为0.3像素左右,方位向为0.1像素左右,完全能够满足雷达立体测图的要求,而且该方法还具有很好的稳健性。     

使用SAR影像生成DEM的精度分析

雷达干涉测量(InSAR)和雷达立体测量(Radargrammetry)是使用SAR影像生成DEM的两种主动遥感新技术,前者利用反射雷达波的相位信息,而后者利用其灰度信息。本文利用ERS-1/2卫星对香港地区成像获取的SAR影像分别构成干涉像对和立体像对生成了DEM,并以外部DEM为参考,利用对比和统计方法分析了两种测量方法的精度情况和技术优势。     

自适应窗口的SAR立体影像匹配方法

针对SAR立体影像间几何畸变对影像匹配的影响,该文提出一种自适应窗口的SAR立体影像匹配方法。首先引入外部粗分辨率DEM,根据影像参数和DEM高程精度约束匹配搜索范围。然后采用归一化互相关和测度进行辅影像匹配窗口自适应扩展匹配,以保证主辅影像匹配窗口内的灰度信息一致;归一化互相关和值最大时的辅影像匹配窗口为最佳匹配窗口,最佳匹配窗口的中心点为获取的匹配点。最后利用双向一致性约束剔除误匹配点。试验结果表明,本文方法在山地区域能有效地增加正确匹配点数量,提高匹配正确率。     

DEM融合算法及其在困难地区测图中的应用

对于我国西部高山区,如横断山脉,高程起伏明显,常年被云雾覆盖,日照稀少,采用传统方法进行地形图测绘存在较大困难,依赖单一方法获取的DEM往往难以满足测图的精度要求。为充分利用不同传感器和不同方法生成的DEM的优点,本文根据各方法的特点,结合小比例尺地形图中低精度的DEM,基于绝对精度等先验知识确定优先级别、相关/干系数确定融合权重,提出了一种包括雷达干涉测量、光学立体摄影测量、不同侧视方向像对雷达立体测图生成的四种多源DEM的像素级融合算法。在横断山脉地区使用所提融合算法进行了实验,获得了一个总体精度得到提高的无缝DEM,实验结果表明新算法为地形复杂的测图困难地区DEM获取提供了一种可能的解决方案。     

含有DEM误差的立体正射影像对上高程量测精度探讨

在DEM支持下,通过引入投影视差光线,以数字正射影像为基础,制作立体辅助影像,并与原正射影像共同构建正射立体影像对,产生与实地相似的几何模型,进行立体观察与量测,可以量测地貌高程,是另外一种构建立体三维环境的思路.然而生成正射影像和辅助影像的原始DEM是含量有误差的.这种误差是否会对产生的立体正射影像对的高程量测结果产生粗差,进而是否影响立体正射影像对的后续使用,这是分析探讨的出发点.理论和实践证明,使用该DEM生成正射立体影像对的左右视差并不受DEM误差的影响,量测高程能够达到一定的精度要求.     

小基高比摄影测量方法及实验分析

传统摄影测量在影像分辨率给定的前提下,为获得尽可能高的高程精度,基本上都采用大基高比(0.6~1)的方案,以实现地形三维信息的可靠高精度的提取。在影像获取系统严格标定和影像匹配精度较高的情况下,小基高比摄影测量同样可以重建可靠的三维信息。文中从数学的角度探讨小基高比立体像对重建高程信息的可能性。对不同基高比的航空影像进行的实验表明,在特征明显区域小基高比立体像对可以获取可靠的高精度的高程信息。     

航空摄影立体像对的全自动影像匹配

在原始影像立体像对的基础上,实现DEM的全自动提取是"数字摄影测量”的最重要的技术,是"摄影测量”对"数字地球”科学体系的最大贡献.DEM全自动提取的关键技术就是立体像对的全自动影像匹配.作者经过多年的实践,分别实现了航空影像立体像对的全自动影像匹配和航天影像立体像对的全自动影像匹配.从自动内定向、自动相对定向、全数字影像匹配等3个子过程论述了实现航空影像DEM全自动提取技术的全过程,并且给出了试验的结果和分析.     

TerraSAR-X数据验证几何纠正影像促进SAR立体影像匹配的可行性

随着SAR的快速发展,国内外学者对SAR的研究越来越深入,SAR立体提取DEM就是其中一个热点。在SAR影像立体提取DEM过程中,SAR立体像对的匹配结果直接关系到提取DEM成果的质量,尤其在地形起伏较大的山区,SAR影像匹配难以获得理想匹配结果。基于此情况,本文提出将基于影响模拟获取的几何纠正影像运用于实现SAR立体影像匹配的设想,并通过实验来验证其可行性。本文利用Terra SAR-X星载SAR数据进行了实验,并通过对实验结果进行统计分析证实了设想的可行性,为解决地形复杂起伏较大的山区SAR影像匹配困难问题提出了一种新思路。     

从SAR影像提取DEM的方法研究

SAR影像自动提取地形信息是雷达遥感研究的一个热门课题,迄今为止,从SAR影像提取DEM的方法可以归结为四类:雷达角度测量,雷达立体测量,雷达干涉测量和雷达极化测量。对这几种方法一一作介绍,着重阐述雷达干涉测量提取DEM技术的原理,并给出DEM提取流程及实例分析。     

星载SAR图像数字测图技术研究

在分析雷达摄影测量技术的发展现状基础上,研究利用SAR立体像对进行摄影测量处理的一种新的理论与方法,主要特点在于利用等效共线方程精确重建SAR图像外方位元素、立体模型建立和误差改正,以及数字测图的实现。最后采用航天资料对以上理论进行验证,得到令人满意的结果。     

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.     

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.     

Toward seamless indoor-outdoor applications: Developing stakeholder-oriented location-based services

Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role.Our specific aim is to solve these issues.This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders.     

地理数据库的关系模型及其实现

本文从以图论观点分析地理实体入手,系统阐述了地理数据库关系模型的设计法和过程。作者于1984年4～9月间在微型机上设计建立了关系型地理数据库的实方验系统(RGDB)。该系统采用了本文提出的关系模型,采用了可动态扩库的子库组合结构,这种结构具有灵活性和提高空间利用率的优点。RGDB含有多种功能的数据操作命令,除了具有一般检索功能外,还能进行“开窗”选取和十分“自由”的映象选取。本文对RGDB系统的主要性能和实现途径作了扼要介绍。     

GIS空间数据的采集误差及其分析

本文详细阐述了GIS数据采集过程中的误差来源，重点分析了通过地图、遥感和摄影测量等方式采集数据所产生的误差及其特性，分析了其对GIS数据的影响与消减方法。