石窟寺三维数字化档案建设方法与技术探讨

文物是不可再生的文化资源,需采用现代科技手段对其进行数字化保护,延续人类历史文明。本文以彬县大佛寺石窟为例,在已有基础地理信息数据、三维激光扫描数据、立面影像数据的基础上,运用CAD建模技术、三维激光扫描技术、虚拟现实技术构建石窟寺三维立体模型,借助CityMaker软件对模型数据、基础地理信息数据及文档资料进行管理。在此基础上,采用基于GIS组件的二次开发方法,借助于CityMaker SDK组件进行三维数字化档案系统开发,探索石窟寺三维数字化档案的建设方法。结果表明,本文提出的方法实现了对石窟寺三维数字化档案的管理,客观详实地记录了石窟寺现状,为文物部门的管理工作提供了便利。     

结合特征分量构建和面向对象方法提取高分辨率卫星影像阴影

针对高分辨率卫星影像,提出一种特征分量构建与面向对象结合的阴影提取方法。分析遥感阴影光谱特性,构建彩色不变特征C3、亮度特征I、主成分第一特征量PC1以及蓝色波段和近红外波段归一化比率特征RATIOb_nir,增强阴影信息。采用线性变换将几个特征分量Digital Number(DN)值归一化到相同范围,对这几个分量进行综合分析。以I和PC1分量为输入对影像进行多尺度分割,建立包括波段均值、标准差、最大差异等特征的规则集,实现面向对象的阴影信息提取。选取20幅QuickBird影像为例进行阴影提取实验,平均总体精度为97%,平均用户精度为96%,平均Kappa系数为0.94。实验结果表明,相对传统基于像素信息提取方法,本文方法提取阴影斑块完整,无破碎图斑;相对基于原始光谱的面向对象方法,本文方法提取精度更高。     

An improved geopositioning model of QuickBird high resolution satellite imagery by compensating spatial correlated errors

A lot of studies have been done for correcting the systematic biases of high resolution satellite images (HRSI), which is a fundamental work in the geometric orientation and the geopositioning of HRSI. All the existing bias-corrected models eliminate the biases in the images by expressing the biases as a function of some deterministic parameters (i.e. shift, drift, or affine transformation models), which is indeed effective for most of the commercial high resolution satellite imagery (i.e. IKONOS, GeoEye-1, WorldView-1/2) except for QuickBird. Studies found that QuickBird is the only one that needs more than a simple shift model to absorb the strong residual systematic errors. To further improve the image geopositioning of QuickBird image, in this paper, we introduce space correlated errors (SCEs) and model them as signals in the bias-corrected rational function model (RFM) and estimate the SCEs at the ground control points (GCPs) together with the bias-corrected parameters using least squares collocation. With these estimated SCEs at GCPs, we then predict the SCEs at the unknown points according to their stochastic correlation with SCEs at the GCPs. Finally, we carry out geopositioning for these unknown points after compensating both the biases and the SCEs. The performance of our improved geopositioning model is demonstrated with a stereo pair of QuickBird cross-track images in the Shanghai urban area. The results show that the SCEs exist in HRSI and the presented geopositioning model exhibits a significant improvement, larger than 20% in both latitude and height directions and about 2.8% in longitude direction, in geopositioning accuracy compared to the common used affine transformation model (ATM), which is not taking SCEs into account. The statistical results also show that our improved geopositioning model is superior to the ATM and the second polynomial model (SPM) in both accuracy and reliability for the geopositioning of HRSI.     

主成分判别分析分类方法在地理国情普查样本解译中的应用

提出了一种主成分判别分析分类方法。通过在地理国情普查样本解译中的应用实验证明,主成分判别分析分类方法能够利用少量的样本实现更优的分类精度。     

Analysis of ASTER data for mapping bauxite rich pockets within high altitude lateritic bauxite,Jharkhand, India

Bauxite deposits of Jharkhand in India are resulted from the lateritization process and therefore are often associated with the laterites. In the present study, ASTER (Advanced Space borne Thermal Emission and Reflection Radiometer) image is processed to delineate bauxite rich pockets within the laterites. In this regard, spectral signatures of lateritic bauxite samples are analyzed in the laboratory with reference to the spectral features of gibbsite (main mineral constituent of bauxite) and goethite (main mineral constituent of laterite) in VNIR–SWIR (visible-near infrared and short wave infrared) electromagnetic domain. The analysis of spectral signatures of lateritic bauxite samples helps in understanding the differences in the spectral features of bauxites and laterites. Based on these differences; ASTER data based relative band depth and simple ratio images are derived for spatial mapping of the bauxites developed within the lateritic province. In order to integrate the complementary information of different index image, an index based principal component (IPC) image is derived to incorporate the correlative information of these indices to delineate bauxite rich pockets. The occurrences of bauxite rich pockets derived from density sliced IPC image are further delimited by the topographic controls as it has been observed that the major bauxite occurrences of the area are controlled by slope and altitude. In addition to above, IPC image is draped over the digital elevation model (DEM) to illustrate how bauxite rich pockets are distributed with reference to the topographic variability of the terrain. Bauxite rich pockets delineated in the IPC image are also validated based on the known mine occurrences and existing geological map of the bauxite. It is also conceptually validated based on the spectral similarity of the bauxite pixels delineated in the IPC image with the ASTER convolved laboratory spectra of bauxite samples.     

GPS高程拟合的方法比较

GPS高程拟合的方法有很多,各有其优点和适用范围。本文在最小二乘估计算法的基础上,讨论主成分估计法和半参数模型估计法及各自的优点,并利用六参数模型的最小二乘估计、主成分估计和半参数模型三种拟合方法对GPS高程进行拟合,通过实例计算结果比较分析,得出半参数估计方法优于其他方法,在一定条件下精度高的优点。最后得出半参数估计方法精度达毫米级,论证了其在实际应用中的优越性。     

Technical research on object-oriented software development platform for multimedia communication

This paper proposes a new method based on principal component analysis to find the direction of an object in any pose. Experiments show that this method is fast, can be applied to objects with any pixel distribution and keep the original properties of objects invariant. It is a new application of PCA in image analysis.     

中国九大古都旅游竞争力研究——以大同为例

对中国九大古都旅游业的发展情况进行比较,选取3个二级指标（城市旅游基础设施竞争力、城市旅游发展现状竞争力和城市旅游生态环境竞争力）25个三级指标,构建古都旅游竞争力评价指标体系.采用主成分分析法对各古都2011年旅游竞争力进行排名,结果显示九大古都旅游业发展不平衡,大同旅游业竞争力较弱,应采取挖掘文化内涵、开发旅游资源、打造旅游产品、加强区域合作、发挥政府作用、加大宣传力度、提高服务质量等措施实现旅游业的可持续发展.     

Visualization and level-of-detail of metadata for interactive exploration of Sensor Web

There are several issues with Web-based search interfaces on a Sensor Web data infrastructure. It can be difficult to (1) find the proper keywords for the formulation of queries and (2) explore the information if the user does not have previous knowledge about the particular sensor systems providing the information. We investigate how the visualization of sensor resources on a 3D Web-based Digital Earth globe organized by level-of-detail (LOD) can enhance search and exploration of information by easing the formulation of geospatial queries against the metadata of sensor systems. Our case study provides an approach inspired by geographical mashups in which freely available functionality and data are flexibly combined. We use PostgreSQL, PostGIS, PHP, and X3D-Earth technologies to allow the Web3D standard and its geospatial component to be used for visual exploration and LOD control of a dynamic scene. Our goal is to facilitate the dynamic exploration of the Sensor Web and to allow the user to seamlessly focus in on a particular sensor system from a set of registered sensor networks deployed across the globe. We present a prototype metadata exploration system featuring LOD for a multiscaled Sensor Web as a Digital Earth application.