三角网至规则格网的快速生成方法及其应用

三角网至规则格网的生成在地形内插和遥感影像配准中小面元微分纠正等方面都具有重要应用。其关键在于快速准确地搜索每个格网点所在的三角形,然后根据三角网顶点信息内插每个格网点的信息。针对格网点在三角网中的定位和内插计算量大的问题,本文提出了一种自适应扫描线填充算法以快速准确地搜索定位出每个格网点所在的三角形;针对地形内插或者小面元微分纠正中每个三角形具有相同运算的特点,采用GPU技术实现了TIN格网内插以及小面元微分纠正并行加速。分别采用大范围自动空三获取的三维点进行地形内插以及大尺寸遥感影像进行微分纠正实验,结果表明本文方法可以有效提高效率。     

大面阵数字航空相机DMZ影像预处理研究

对国产新型内拼式大面阵数字航测相机DMZ原型系统获取的数字影像进行几何预处理的方法进行了研究;在分析DMZ全色成像光路特点的基础上,提出了多相机联合的影像几何校正与缝合方法,生成等效虚拟立体影像。利用等效虚拟立体影像进行了3种布控方案的数字空三平差和精度分析,验证了该方法的正确性和可靠性,实现了对DMZ影像预处理的探索性研究。     

森林面积遥感估测研究

深入探讨了图像处理方法、分类原理等基本理论;依据研究区内植被的光谱特征,选择合适的遥感数据源并对数据进行预处理;通过对植被光谱特征、植被指数等关键因子的分析,选择特征提取的方法,进行了初步的计算机自动分类;根据分类结果,计算宣城市森林面积。不仅可以弥补人工实地调查中工作量大、调查周期长,资源数据速度慢、精度低等缺点,还可以发挥其信息量大、检测手段先进等优点,使得快速、准确地完成森林面积估算成为现实。     

国标矢量数据格式转换几何精度评估模型比较

通过对国标矢量数据转换过程的分析,研究转换过程中几何精度损失的具体问题,提出了三种用于检验转换过程中几何精度损失的评估模型。实验结果表明,该评估模型在不同数据量和数据难度的情况下所产生的结果和模型的复杂度有较大关系。     

IGS精密钟差文件的读取及加密方法

利用Fortran语言编程实现了精密钟差文件的读取及信息筛选;在此基础上,利用滑动式Lagrange插值方法对精密钟差进行了加密,并对结果进行分析与讨论,得出了几点有益的结论。     

非理想观测环境下精密单点定位应用研究

摘要-对非理想观测环境下,采用GPS精密单点定位技术施测1：10000像片控制点的可行性进行了研究,通过采用不同软件、不同案例、不同解算方法所获得的数据进行分析,得出了满足精度要求的结论,编写了适合云南高原山区的精密单点定位技术像控点施测技术规定。     

精密单点定位在ADS80快速正射影像图制作中的应用

利用精密单点定位技术可为ADS80相机获取的影像直接定向,在自动提取DEM的基础上直接进行正射影像纠正,从而省去空三工序,大幅度缩短成图周期。试验结果表明利用本方法生成的正射影像图可以满足相关精度要求。     

均值漂移粒子滤波的动态精密单点定位

粒子滤波以大量粒子计算为代价削弱动态精密单点定位的非线性方程线性化、非高斯噪声正态化造成的精度损失,这也带来计算效率较差的问题。针对计算效率低的问题,将均值漂移算法引入到粒子滤波,减少粒子选取个数,提高动态PPP中待估参数的计算效率。以某机载GPS数据为例,基于均值漂移算法的粒子滤波大大削减了粒子个数,计算效率有一定程度的提高。     

基于ENVI／IDL与ArcGIS Engine的GCP选取与实现

针对遥感图像几何校正中GCP选取受人为因素影响较大、分布与数量难以确定等问题,在分析图像局部特征的基础上,结合Voronoi图,基于ENVI／IDL与ArcGISEngine一体化开发技术,研究了一种具有半自动选取和空间分析功能的GCP选取方法。实验通过一幅面积为3278．47km。的遥感图像进行几何校正,结果表明本文研究的GCP选取方法可以将工作效率提高近一倍,总RMS可降低约0．3个像素,在实际生产中具有一定的参考意义。     

An improved approach for the production of satellite-based geospatial reference imagery

Abstract

An innovative and practical satellite image product is described that is ideal for applications in Northern Canada because of its wide area coverage and mapping-quality features. This product is generated from a new procedure developed at the Canada Centre for Remote Sensing (CCRS) for processing Landsat 7 imagery, and by extension, imagery from other Earth Observation satellites. By working with multiple satellite passes, each containing the equivalent of multiple scenes, the new procedure could dramatically reduce the turn-around time for generating georeferenced image products, and also increase their geometric and radiometric accuracy compared to those produced by the current methods. The objective of the process has been to generate satellite image mosaics covering large areas (e.g. >500 000 km²) with uniformly distributed errors at sub-pixel resolution. The paper discusses the theoretical basis of a photogrammetric adjustment for satellite imagery and the results obtained from several tests. The process is generic, involving a sensor model, a satellite orbit model and ground control information; thus it may be easily adapted to any satellite that allows for repeat coverage with overlapping paths. By performing an adjustment to correct the satellite position and attitude data prior to the production of orthoimage products, it is possible to create a mosaic with a single resampling process which minimises both the radiometric and geometric resampling artifacts. The results from three separate tests are presented, along with a discussion of the procedures that were followed in each case. All three tests have successfully demonstrated that sub-pixel sample size errors may be consistently obtained over large areas. A by-product process developed to support the measurement of ground control point coordinates for the satellite adjustment was the automatic matching of geographic features such as lakes and islands in vector data format. This has been a significant development in that it has eliminated manual intervention in the measurement of these features in the imagery, allowing the ground control for entire passes containing several scenes to be obtained in minutes instead of hours.