共查询到20条相似文献，搜索用时 31 毫秒
1.
Relative orientation is one of the fundamental steps in forming a photogrammetric model. Whilst relative orientation is straightforward in most cases of aerial photogrammetry this may not be the case in close range photogrammetry where the nature of the photographs and the cameras being used often raise unfamiliar problems. This paper addresses the problem of performing relative orientation of non-metric photographs under unstable conditions where there are no ground control points and the ray intersection geometry is poor. The relative orientation problem is approached from several viewpoints, including a method that relies on little information about the exterior or relative orientation parameters. The solution is based on an iterative process, in which a set of three virtual control points (VCPs) is created, using photo coordinates and range ratios. The validity of the VCPs is checked during every iteration by an estimation of the coplanarity condition using two or more conjugate checkpoints. During the iteration a database is formed, which is then used to obtain a net of VCPs that fulfil the coplanarity condition for the checkpoints. The VCPs are then used to compute the "relative" exterior orientation by space resection. The proposed method was tested on both simulated and real photographs and was found to have some advantages over more commonly used techniques. 相似文献
2.
对射影空间中摄影测量的一些基本问题进行了研究,建立了射影空间中物像之间的共线条件关系式、物像之间的直接关系式以及同名像点之间的共面条件关系式。 相似文献
3.
This paper is concerned with using linear features in aerial triangulation. Without loss of generality, the focus is on straight lines with the attempt to treat tie lines in the same fashion as tie points. The parameters of tie lines appear in the block adjustment like the tie points do. This requires a unique representation of lines in object space. We propose a four-parameter representation that also offers a meaningful stochastic interpretation of the line parameters. The proposed line representation lends itself to a parameterized form, allowing use of the collinearity model for expressing orientation and tie line parameters as a function of points measured on image lines. The paper describes in detail the derivation of the extended collinearity model and discusses the advantages of this new approach compared to the standard coplanarity model that is used in line photogrammetry. The intention of the paper is to make a contribution to feature-based aerial triangulation on the algorithmic level. 相似文献
4.
Surface Matching and Change Detection Using a Modified Hough Transformation for Robust Parameter Estimation 总被引：3，自引：0，他引：3
Many photogrammetric and GIS applications, such as city modelling, change detection and object recognition, deal with surfaces. Change detection involves looking for differences between two surface models that are obtained from different sensors, for example an optical sensor and a laser scanner, or by the same sensor at different epochs. Surfaces obtained through a sampling process may also have to be compared for future processing (for example transformation parameter estimation and change detection). Surface matching is therefore an essential task in these applications. The matching of surfaces involves two steps. The first step deals with finding the correspondences between two surface points and/or patches. The second step requires the determination of transformation parameters between the two surfaces. However, since most surfaces consist of randomly distributed discrete points and may have different reference systems, finding the correspondences cannot be achieved without knowing the transformation parameters between the two surfaces. Conversely, deriving the transformation parameters requires the knowledge of the correspondence between the two point sets. The suggested approach for surface matching deals with randomly distributed data sets without the need for error prone interpolation and requires no point-to-point correspondence between the two surfaces under consideration. This research simultaneously solves for the correspondence and the transformation parameters using a Modified Iterated Hough Transform for robust parameter estimation. Several experiments are conducted to prove the feasibility and the robustness of the suggested approach, even when a high percentage of change exists. 相似文献
5.
The integration of topographic data sets is defined as the process of establishing relationships between corresponding object instances in different, autonomously produced, topographic data sets of the same geographic space. The problem of integrating topographic data sets is in finding these relationships, considering the differences in content and abstraction. A conceptual framework is developed. Components of this framework are ontologies and sets of surveying rules. New in this approach is the introduction of a reference model. A reference model belongs uniquely to the combination of topographic data sets to be integrated. The framework is tested on two topographic data sets with area instances (polygons) which have crisp and complete boundaries and are not displaced for cartographic reasons. The overall conclusion is that the ontology-based framework is feasible, if (1) there is (at least partial) knowledge of the surveying rules, and (2) the data sets can be synchronized in time. The application of this framework is most suitable for object classes with instances that are easy to identify and have a limited spatial extent (e.g., buildings). 相似文献
6.
《ISPRS Journal of Photogrammetry and Remote Sensing》2007,61(6):355-370
Point cloud acquisition by using laser scanners provides an efficient way for 3D as-built modelling of industrial installations. Covering such an installation with point cloud data often requires data acquisition from multiple standpoints. Before the actual modelling can start the transformation parameters of all scans need to be determined. Two methods to register point clouds of industrial scenes with different coordinate definitions are presented. Corresponding object models in different scans are used to determine the translation and rotation parameters of the scans. The first method, called Indirect method, is a two-step approach as object fitting and registration of the scenes is done separately. The second method, called Direct method simultaneously determines the shape and pose parameters of the objects as well as the registration parameters. Both methods are designed such that optimal use can be made of the knowledge of shapes present in industrial environments. Compared to ICP the presented approach combines registration and modelling and thus avoids the accumulation of errors. Furthermore, the simultaneous registration of multiple scans is possible. The presented approaches are based on non-linear least squares and provide quality measures in the form of covariance matrix of the estimated parameters, which can be used to decide if more scans are needed, and how and where they should be captured. Results are presented on some point cloud data-sets from actual industrial sites, where registration was done without using any artificial targets. 相似文献
7.
提出了一种基于横向切片的地物可量测性三维重构方法,利用平面单应变换和未标定的多视图完成三维重建。通过对重构物体成像进行轮廓约束及场景约束,假设一组平行平面切割重构地物,通过单应变换得到切片的轮廓线构成物体的形状,进而恢复各层轮廓线的三维值,并加入参考高度,求得重构物体的高度。实验证明了此方法对规则与不规则物体的重建均有效,使得整个三维的求解过程具有可测量性。 相似文献
8.
两种SAR数据目标定位的比较 总被引：2，自引：2，他引：0
和以前的定位方法相比,距离-多普勒(R—D)定位法因不需要选地面参考点进行定位,在许多遥感应用方面具有独特的优势和重要意义。本文论述了利用卫星星历数据和雷达回波数据的距离-多普勒信息对SAR图像目标定位的原理,并对相对位置定位算法的计算公式进行了推导。通过该定位方法对Radarsat和ERS图像目标进行了定位,详细说明了轨道参数、斜距参数、多普勒参数等获取方法,比较了这两种数据目标定位具体算法和精度的差异。 相似文献
9.
无地面控制点的星载SAR影像直接对地定位研究 总被引：2，自引：0，他引：2
针对星栽合成孔径雷达（SAR）对地面目标的定位问题，分析了在无地面控制点的情况下，利用距离-多普勒（R-D）模型和地球模型进行对地定位的理论与方法，给出了在无地面控制点（GCP）而有数字高程模型的情况下利用R-D模型进行对地定位的求解方法。用天津地区ERS-1数据进行实验，其结果与当地地形图进行比较，精度在50m以内，表明该文提出的方法是正确、可行的。 相似文献
10.
11.
We present an automatic approach for object extraction from very high spatial resolution (VHSR) satellite images based on Object-Based Image Analysis (OBIA). The proposed solution requires no input data other than the studied image. Not input parameters are required. First, an automatic non-parametric cooperative segmentation technique is applied to create object primitives. A fuzzy rule base is developed based on the human knowledge used for image interpretation. The rules integrate spectral, textural, geometric and contextual object proprieties. The classes of interest are: tree, lawn, bare soil and water for natural classes; building, road, parking lot for man made classes. The fuzzy logic is integrated in our approach in order to manage the complexity of the studied subject, to reason with imprecise knowledge and to give information on the precision and certainty of the extracted objects. The proposed approach was applied to extracts of Ikonos images of Sherbrooke city (Canada). An overall total extraction accuracy of 80% was observed. The correctness rates obtained for building, road and parking lot classes are of 81%, 75% and 60%, respectively. 相似文献
12.
Huiye Ma Nicole Ronald Theo A. Arentze Harry J. P. Timmermans 《Journal of Geographical Systems》2013,15(4):427-451
Agent-based simulation has become an important modeling approach in activity-travel analysis. Social activities account for a large amount of travel and have an important effect on activity-travel scheduling. Participants in joint activities usually have various options regarding location, participants, and timing and take different approaches to make their decisions. In this context, joint activity participation requires negotiation among agents involved, so that conflicts among the agents can be addressed. Existing mechanisms do not fully provide a solution when utility functions of agents are nonlinear and non-monotonic. Considering activity-travel scheduling in time and space as an application, we propose a novel negotiation approach, which takes into account these properties, such as continuous and discrete issues, and nonlinear and non-monotonic utility functions, by defining a concession strategy and a search mechanism. The results of experiments show that agents having these properties can negotiate efficiently. Furthermore, the negotiation procedure affects individuals’ choices of location, timing, duration, and participants. 相似文献
13.
M. Hotine 《Journal of Geodesy》1966,40(3):195-224
The properties of conformal transformations developed in the previous paper (Hotine 1965) are used to construct triply orthogonal
coordinate systems from a scalar N. Classical doctrine on the subject requires that N should satisfy a third-order partial
differential equation known as the Darboux equation, whereas no such restriction seems necessary in the conformal approach.
If the Darboux equation is not a condition for triple orthogonality, but a property of the space, as this investigation suggests
may be the case, then the effect on the geometry of the gravitation field would be considerable. It is accordingly important
to resolve the question.
The properties of triply orthogonal systems are worked out in some detail and are valid in all cases where a triply orthogonal
system exists, whether or not the Darboux equation is a necessary condition.
Some formulae in the differential geometry of curves and surfaces are required which are not to be found in the standard literature.
For this reason, as well as to provide a clear statement of the conventions adopted, it has been necessary to provide a condensed,
but connected, account of this subject in an appendix. References to the Appendix are in the form (10A). Inevitably in a connected
account, some well-known relations are recovered, but they are usually arrived at by a new and shorter route and do serve
to illustrate the method. 相似文献
14.
15.
The determination of the attitude, the position and the intrinsic geometric characteristics of the camera is recognised as the fundamental photogrammetric problem. It can be summarised as the determination of camera interior and exterior orientation parameters, as well as the determination of 3D coordinates of object points. The term "exterior orientation"of an image refers to its position and orientation related to an exterior (object space) coordinate system. Several methods can be applied to determine the parameters of the orientation of one, two or more photos. The orientation can be processed in steps (as relative and absolute orientation) but simultaneous methods (such as bundle adjustments) are now available in many software packages. Several methods have also been developed for the orientation of single images. They are based in general on geometric and topological characteristics of imaged objects.
This paper presents a survey of classical and modern methods for the determination of the exterior parameters in photogrammetry, some of which are available as software packages (with practical examples) on the Internet. The methods presented are classified in three principal groups. In the first, a selection of approximate methods for applications that do not require great accuracy is presented. Such methods are also used to calculate values required for iterative processes. In the second group, standard point–based methods derived from collinearity, coplanarity or coangularity conditions are briefly reviewed, followed by line–based approaches. The third group represents orientation methods based on constraints and on concepts of projective geometry, which are becoming of increasing interest for photogrammetrists. In the last section, the paper gives a summary of existing strategies for automatic exterior orientation in aerial photogrammetry. 相似文献
This paper presents a survey of classical and modern methods for the determination of the exterior parameters in photogrammetry, some of which are available as software packages (with practical examples) on the Internet. The methods presented are classified in three principal groups. In the first, a selection of approximate methods for applications that do not require great accuracy is presented. Such methods are also used to calculate values required for iterative processes. In the second group, standard point–based methods derived from collinearity, coplanarity or coangularity conditions are briefly reviewed, followed by line–based approaches. The third group represents orientation methods based on constraints and on concepts of projective geometry, which are becoming of increasing interest for photogrammetrists. In the last section, the paper gives a summary of existing strategies for automatic exterior orientation in aerial photogrammetry. 相似文献
16.
Erik W. Grafarend Ivan I. Mueller Haim B. Papo Burghard Richter 《Journal of Geodesy》1979,53(3):195-213
Modern high accuracy measurements of the non-rigid earth are to be referred to four-dimensional, i.e., time- and space-dependent
reference frames. Geodynamic phenomena derived from these measurements are to be described in a terrestrial reference frame
in which both space- and time-like variations can be monitored. Existing conventional terrestrial reference frames (e.g. CIO,
BIH) are no longer suitable for such purposes.
The ultimate goal of this study is the establishment of a reference frame, moving with the earth in some average sense, in
which the geometric and dynamic behavior of the earth can be monitored, and whose motion with respect to inertial space can
also be determined.
The study is conducted in several parts. In the first part problems related to reference directions are investigated, while
subsequent parts deal with positions, i.e., with reference origins and scale. Only the first part is treated in this paper.
The approach is based on the fact that reference directions at an observation point on the earth surface are defined by fundamental
vectors (gravity, earth rotation, etc.), both space and time variant. These reference directions are interrelated by angular
parameters, also derived from the fundamental vectors. The interrelationships between these space- and time-variant angular
parameters are illustrated in a commutative diagram, tower of triads, which makes the derivation of the various relationships
convenient. In order to determine the above parameters from observations using least squares techniques, a model tower of
triads is also presented to allow the formation of linear observation equations. Although the model tower is also space and
time variant, its variations are described by adopted parameters representing our current knowledge of the earth. 相似文献
17.
建立实用的遥感图像分析系统涉及诸多因素，其中，形成有效的目标提取算法体系和设立适于目前人工智能水平的基于知识的框架是两个核心问题。本文提出了一种利用对光谱特征空间分布进行可视化图形处理的新的分类方案，继而以光谱、纹理和空间知识对分类结果进行优化。这种集可视化分析、栅格ＧＩＳ处理功能和人类判读专家知识于一体的系统为解决遥感图像地物识别这一复杂问题提供了有效途径。 相似文献
18.
最佳DEM分辨率的确定及其验证分析 总被引：2，自引：0，他引：2
在玛尔挡地区格网DEM的数据上选择实验样区,以不同分辨率情况下DEM数据对地表模拟表达的逼近程度为研究对象,最优逼近时的栅格单元大小的临界值就是所求的最佳分辨率。在分析坡度中误差法和公式法等常见方法的基础上,借鉴坡度中误差的思想,选取区域地形粗糙度K、剖面线长度SL两个定量指标来综合分析确定该地区格网DEM的最佳分辨率。在ArcGIS平台上对方法进行了实验验证,得出分别以2m和8m作为玛尔挡地区1∶10 000和1∶50 000 DEM生产时是最佳分辨率的结论。研究表明这种解决办法不仅可以克服GIS空间分析中DEM分辨率确定的盲目性和随意性,而且能确保基于DEM的各种空间分析的精度,为相关研究提供重要的参考价值。 相似文献
19.
The major contribution of this paper relates to the practical advantages of combining Ground Control Points (GCPs), Ground Control Lines (GCLs) and orbital data to estimate the exterior orientation parameters of images collected by CBERS-2B (China–Brazil Earth Resources Satellite) HRC (High-resolution Camera) and CCD (High-resolution CCD Camera) sensors. Although the CBERS-2B is no longer operational, its images are still being used in Brazil, and the next generations of the CBERS satellite will have sensors with similar technical features, which motivates the study presented in this paper. The mathematical models that relate the object and image spaces are based on collinearity (for points) and coplanarity (for lines) conditions. These models were created in an in-house developed software package called TMS (Triangulation with Multiple Sensors) with multi-feature control (GCPs and GCLs). Experiments on a block of four CBERS-2B HRC images and on one CBERS-2B CCD image were performed using both models. It was observed that the combination of GCPs and GCLs provided better bundle block adjustment results than conventional bundle adjustment using only GCPs. The results also demonstrate the advantages of using primarily orbital data when the number of control entities is reduced. 相似文献
20.
简单面目标与带孔洞面目标间拓扑关系的层次表达方法 总被引：1，自引：1，他引：0
带孔洞的面目标是现实中较为常见的一类复杂目标,它们之间的拓扑关系要比简单面目标复杂得多.本文基于空间划分和目标分解的思想,利用点集(拓扑学)理论中的邻域概念详细分析和描述带孔洞面目标的点集拓扑分量,这种描述方法实质上是简单面目标点集拓扑分量描述的一种自然延展.进而,对简单面目标间拓扑关系的描述和区分方法进行了扩展,层次地分析和区分简单面目标与带孔洞面目标间的拓扑关系.相比于Egenhofer等人提出的代数描述和间接表达方法,本文提出的方法是一种直接描述和层次表达的方法,并且与简单面目标间拓扑关系的表达方法是相统一的. 相似文献