共查询到19条相似文献,搜索用时 156 毫秒
1.
2.
3.
铅垂线辅助的大比例尺城区空三自动转点 总被引:1,自引:0,他引:1
利用城区航空影像中存在的大量铅垂线,提出了一种铅垂线辅助的多影像匹配算法.该算法应用于大比例尺城区的空三自动转点,大大提高了自动转点的成功率. 相似文献
4.
依据灭点理论,推导了空间铅垂线与航空影像的空间姿态角之间的关系及其相应的误差方程式,并分析了铅垂线辅助的单像空间后方交会和单模型绝对定向中所需的控制点数。最后,通过实际数据的试验研究了铅垂线辅助的单像空间后方交会和单模型绝对定向的精度与可靠性。试验结果表明,在传统的单像空间后方交会和单模型绝对定向中引入铅垂线约束条件,不仅定向精度与传统的基于控制点的绝对定向精度相当,而且可以减少所需的控制点数以及定向精度对控制点分布的依赖性。 相似文献
5.
吴立果 《测绘与空间地理信息》2021,44(8):188-190
空中三角测量是测绘生产中的重要环节,在甘南州北部1:10000地形图测绘中,空中三角测量使用ADS100相机获取的航空影像,采用无控制点约束的区域网平差方法,克服了高原山区影像难以获取的困难,摆脱了像控点施测困难对测绘生产的影响,显著提高了测绘生产的效率,降低了生产成本. 相似文献
6.
针对传统无人机影像空中三角测量需要大量外业控制点的问题,提出通过高分辨率遥感卫星影像空间定位获取地面点坐标,并将这些地面点作为无人机影像的控制点来源,以此辅助无人机空中三角测量。在基于RPC模型的高分辨率遥感影像空间定位的基础上,采取多种控制点布设方案进行了无人机影像空中三角测量,并对比分析了各布控方案对试验精度的影响及原因。试验结果表明,在不采用外业实测控制点的情况下,只用高分辨率遥感影像空间定位得到的加密点作全局控制,平差后检查点平面精度可达到0.629 m,高程精度可达到0.823 m,如果要保证更高的空三精度,可在测区四周及中心增加少量外业实测控制点。 相似文献
7.
8.
9.
10.
《测绘科学》2020,(1):116-122
针对摄影测量中因连接点数目过多而导致空中三角测量过程耗时久的问题,该文提出了一种在像方进行的基于贪心策略的连接点筛选方法,能够有效的提高空中三角测量的处理速度。首先对影像进行特征点提取与匹配,采用并查集的方法对特征点进行多视追踪,然后对每张影像上参与匹配的特征点构建点与点的距离索引表。接着,依照该文提出的基于贪心策略的方法对常用的连接点筛选方法进行改进,筛选出正确且具有代表性的连接点子集,减少连接点的数量,降低光束法平差的计算量,从而完成空中三角测量。通过近景和航空影像数据集上的实验结果表明,该文筛选方法能够控制连接点的数量和分布,可以在保证像点和检查点精度的基础上,将空中三角测量的计算速度提高3~4倍。 相似文献
11.
12.
Xiuxiao Yuan Jianhong Fu Hongxing Sun Charles Toth 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(6):541-550
In traditional GPS-supported aerotriangulation, differential GPS (DGPS) positioning technology is used to determine the 3-dimensional coordinates of the perspective centers at exposure time with an accuracy of centimeter to decimeter level. This method can significantly reduce the number of ground control points (GCPs). However, the establishment of GPS reference stations for DGPS positioning is not only labor-intensive and costly, but also increases the implementation difficulty of aerial photography. This paper proposes aerial triangulation supported with GPS precise point positioning (PPP) as a way to avoid the use of the GPS reference stations and simplify the work of aerial photography.Firstly, we present the algorithm for GPS PPP in aerial triangulation applications. Secondly, the error law of the coordinate of perspective centers determined using GPS PPP is analyzed. Thirdly, based on GPS PPP and aerial triangulation software self-developed by the authors, four sets of actual aerial images taken from surveying and mapping projects, different in both terrain and photographic scale, are given as experimental models. The four sets of actual data were taken over a flat region at a scale of 1:2500, a mountainous region at a scale of 1:3000, a high mountainous region at a scale of 1:32000 and an upland region at a scale of 1:60000 respectively. In these experiments, the GPS PPP results were compared with results obtained through DGPS positioning and traditional bundle block adjustment. In this way, the empirical positioning accuracy of GPS PPP in aerial triangulation can be estimated. Finally, the results of bundle block adjustment with airborne GPS controls from GPS PPP are analyzed in detail.The empirical results show that GPS PPP applied in aerial triangulation has a systematic error of half-meter level and a stochastic error within a few decimeters. However, if a suitable adjustment solution is adopted, the systematic error can be eliminated in GPS-supported bundle block adjustment. When four full GCPs are emplaced in the corners of the adjustment block, then the systematic error is compensated using a set of independent unknown parameters for each strip, the final result of the bundle block adjustment with airborne GPS controls from PPP is the same as that of bundle block adjustment with airborne GPS controls from DGPS. Although the accuracy of the former is a little lower than that of traditional bundle block adjustment with dense GCPs, it can still satisfy the accuracy requirement of photogrammetric point determination for topographic mapping at many scales. 相似文献
13.
14.
15.
GPS辅助光束法平差的理论精度 总被引:1,自引:0,他引:1
袁修孝 《武汉大学学报(信息科学版)》1998,(4)
采用一组带GPS导航数据的实际航摄资料,通过平差计算出精度矩阵Qxx的数值,对GPS辅助光束法平差的理论精度变化规律进行了全面讨论。以此为基础,从理论上给出最佳区域网的大小、地面控制点的布设等实用技术要求。此外,还探讨了GPS用于单航线航空摄影测量加密的可行性和具体实施方案。 相似文献
16.
结合某测区天绘影像无控空中三角测量的任务,在分析无控空中三角测量技术流程的基础上,针对天绘卫星影像的特点,对自由网平差之前的连接点选择与调整、空三前后的精度检测等关键步骤的技术要点进行了探讨。本文所讨论的技术流程和方法均在此次空三任务中得到了较好的运用与验证。 相似文献
17.
研究非量测CCD数码相机应用于航空摄影测量的技术方法.采用基于自检校光束法平差严格标定非量测CCD数码相机;提出基于相对定向、三视张量、自由光束法平差、区域网光束法平差的空中三角测量流程.实验表明,严格标定的数码相机,可以应用于大比例尺航空摄影测量. 相似文献
18.
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
19.
L. P. Adams 《The Photogrammetric Record》1968,6(32):188-195
Some methods of adjusting the vertical height errors produced in a strip of aerial triangulation are discussed and a semi-graphic method of adjustment suggested. 相似文献