数字近景摄影测量中人工标志点快速自动匹配

针对数字近景摄影测量中的人工标志点快速自动匹配问题,提出了一种基于双片空间前方交会的匹配算法。首先,通过计算投影线间的最短距离确定一组初始匹配点;然后通过双片空间前方交会计算相应物方点坐标;最后反求该物方点坐标在其他像片上的像点坐标,通过比较该像点与初始匹配点的坐标差确定同名像点。两组实验均证明,该算法计算速度快,具有高匹配率和低误匹配率。     

基于核面约束的近景摄影测量影像人工标志点匹配方法

提出了一种基于已知点和核面约束的近景摄影测量人工标志点分组匹配算法。首先利用定向棒点和编码标志点等已知点对所有像片进行分组;然后按三张一组进行组合,并计算各组合的几何质量;最后选择几何质量最好的部分像片进行组合,按核面约束进行匹配。实验证明,该算法匹配100余张像片1、0 000余像点的速度约为5 s,像点匹配率高于95%,误匹配率低于0.1‰,满足近景摄影测量的要求。     

近景摄影测量中人工标志点及其定位方法综述

数字近景摄影测量中人工标志点的识别和子像素定位是进行同名点匹配和三维重建的基础。通过对目前常用的圆形标志点、方形对顶角标志、十字形标志的特点和常用子像素定位方法及定位精度的分析,总结出了上述各种人工标志点的适用范围。     

多基线-数字近景摄影测量

根据交会精度与影像匹配自动化的需要,与当今航空数码相机沿航线方向视场角偏小的事实,阐述了大重叠、多基线摄影测量的必要性及其现实意义;重点介绍了利用非量测相机进行多基线的正直、交向摄影方法与数据处理的特点,特别是“多基线交向摄影”,通过多次、多相机对三峡工程地下电站尾水边坡进行拍摄试验,获得了传统非量测相机难以比拟的、非常满意的结果。     

多基线数字近景摄影测量在建筑立面提取中的应用

多基线数字近景摄影测量利用旋转或平行摄影方式,通过相邻光束交会角小来提高匹配精度和速度,以短基线大重叠度增加总体交会角来提高点位解算精度,为解决匹配、交会角和精度3者之间的矛盾提供了有效的途径,且具有不接触对象、精度高、外业简单等优点,被越来越多地应用于实际的工程中。最后采用多基线数字近景摄影测量完成某建筑物立面的提取,满足规范的要求,验证了多基线数字近景摄影测量具有良好的工程应用价值。     

近景摄影测量技术在数字城市中的应用

介绍了基于近景摄影测量技术建立数字城市的方式以及实际成果应用现状,并以故宫古代建筑物的数字化测绘和古代建筑遗迹为研究对象,结合激光扫描成像测量技术,探索了一种建立数字城市的新方法。     

数字近景摄影测量在古建筑物重建中的应用研究

讨论了一种建立古建筑复杂表面构件的三维模型的方法.在工程作业现场,用数码相机 PC机 摄影测量软件 CAD的方法建立复杂构件的DSM.实践证明,这种方法是非常有效的.     

基于GPS的近景测量定位方法研究

本文介绍了基于GPS的近景测量定位方法所需硬件的集成方式及功能,分析了该方法定位的基本原理,并对试验结果进行了分析,验证该方法的可行性及定位精度.利用交向摄影方式,用一台相机,分别在两个摄站点获取同一范围的影像,利用数字罗盘测相机的姿态,GPS测摄站点坐标,利用单片后方交会及像对前方交会解求待定地物点的三维坐标,为不易...     

数字近景摄影测量建筑容积率调查技术研究

城市建筑容积率是城市土地利用集约化程度的一个重要标志。基于遥感影像进行容积率调查的方法应用范围广,但误差较大。本文将数字近景摄影测量技术应用于精准容积率调查,研究了基于数字地图的单张像片参数以及顾及空间固定条件的立体像对前方交会方法,实现高精度的三维坐标获取。本文将普通数码相机和PDA相结合,辅助以GPS和全站仪等,实现了价格低廉、应用灵活快速的容积率调查集成系统,能够现场完成数据采集、存储。     

旋转多基线数字近景摄影测量

提出了一种全新的数字近景摄影测量方法——旋转多基线数字近景摄影测量。该方法通过应用旋转摄影增大了摄影视场角,应用“多基线”的摄影方式增大了摄影交会角,提高了交会精度,并且解决了近景摄影测量中大交会角影像难以实现自动匹配的困难。同时,该方法将传统的区域网空中三角测量应用于近景摄影测量,用于影像外方位元素的解算,在提高精度的同时减少了外业工作量,提高了生产效率。     

Some Thoughts on the Emergence of Digital Close Range Photogrammetry

This presentation offers some thoughts on the emergence (that is essentially to say the commercial acceptance and exploitation) of close range digital photogrammetric systems. The discussion is restricted to systems based on standard photogrammetric processes involving digital frame imagery. Systems are classified into three tiers which are distinguished not only by accuracy and cost, but also by the degree to which a technology transfer has taken place from the specialist photogrammetrist to the non-specialist user. This technology transfer, it will be argued, has facilitated dramatic growth in the application of low accuracy, low cost three dimensional modelling systems in areas such as heritage recording, multimedia, process plant documentation and forensic photogrammetry. Along with automation, this technology transfer has also largely accounted for the wider use of high accuracy, high cost, off line and real time vision metrology systems in large scale industrial metrology. Rapid growth in these two system categories is then contrasted against the more modest advances being witnessed in the traditional close range photogrammetric service sector. Prospects for the future are also touched upon.     

多基线数字近景摄影测量在建筑工程中的应用

多基线数字近景摄影测量与传统近景摄影测量相比,具有短基线、大重叠度的特点,短基线使得相邻光束交会角较小,易于提高影像匹配精度;大重叠度使得首尾交会角较大,从而可提高空间点定位精度。该方法有效地解决了影像匹配、交会角和点定位精度三者之间存在的矛盾。首先,利用非量测数码相机进行多基线平行摄影,借助Lensphoto软件实现建筑物立面点坐标的量测,并将其与高精度莱卡全站仪测量结果进行精度对比,最后分析控制点个数与点位精度之间的关系。实验表明,多基线近景摄影测量在建筑工程测量中可以取得较高的点位精度,控制点个数的增加会提高点位精度,但存在一定极限。     

基于Lensphoto系统的土石方计算方法应用

土石方计算工程的实际意义非常重大,因而选择基于多基线数字近景摄影测量系统的土石方计算方法进行了研究,并通过实例与其他常用土石方计算方法进行了比较,结果表明多基线近景摄影测量技术在土石方计算中具有速度快、精度高、工作流程简单等特点.     

近景摄影测量的控制

论述了近景摄影测量中实施控制的目的、分类与方法,提示可以多方法地建立物方空间坐标系,建议统一转角系统舍去地面摄影测量系统,指明控制的测定精度要求,提出建立特高精度工业控制网的理论与方法,总结了几种特殊的控制方法。     

An Application of Close Range Photogrammetry In Dolphin Studies

Dolphins are agile animals and are very difficult to measure at sea. However, for the conservation of threatened or endangered species, measurement may be vital because it allows a demographic analysis of the population. Hector's dolphin (Cephalorhynchus hectori) is a rare species living only in coastal waters around New Zealand where it is studied from small boats. This paper describes a stereophotogrammetric technique developed to measure body length accurately at sea without having to capture the individual. Constant calibration with the use of a control frame allowed accurate body length measurements of dolphins to be made with this low cost system, with a measurement error of 4 per cent to 6 per cent of actual length.     

Assessment of Dem Quality for Characterizing Surface Roughness Using Close Range Digital Photogrammetry

This paper presents a procedure for assessing the quality of a digital elevation model (DEM) which has been applied to the output of a normalized cross correlation based stereomatching algorithm. Using semimetric photography of natural gravel river bed surfaces acquired in the field, digital photogrammetry was used to extract DEMs automatically for use in characterizing surface roughness properties. The procedure for assessing DEM quality involves examination of (i) ortho-images, to provide a qualitative check on stereomatching performance; (ii) DEM collection statistics which quantify the percentage of correctly matched pixels as a function of those interpolated; and (iii) height differences between check points, measured using independent field survey, and corresponding DEM points. The concepts of precision, accuracy and reliability are defined in the context of DEM quality assessment and methods are outlined which can be used to assess these variables. The assessment is conducted for two adjacent stereopairs with similar characteristics, considering the effects of both DEM collection parameters and different lens models upon DEM quality. Results show that digital photogrammetry, in conjunction with independent field survey, can be used successfully for extracting high resolution, small scale DEMs from natural gravel surfaces. Components (i) and (ii) of the quality assessment suggest the need to optimize DEM collection parameters, although the effects of not using a properly specified lens model were minimal at this scale. Method (iii) showed that increasing stereomatching success does not necessarily lead to more accurately estimated DEM points. However, the use of method (iii) remained difficult because of the scale of the photogrammetric application being used; check point positioning within the photogrammetric co-ordinate system was only possible to ±10 mm which, for a gravel bed surface, was associated with elevation variance of a similar, sometimes greater, magnitude. The next stage of this research will require the use of higher quality check data, possibly from laser profiling.     

工业现场近景数字摄影视觉精密测量

研究了基于近景数字摄影原理的现场三维精密视觉测量方法,对其核心技术:数字成像器件模型及标定、高精度亚像素图像处理算法以及光学编码与精密测头技术进行了深入的讨论,给出了实现思路,为工业现场近景数字摄影精密测量系统的设计提供了理论依据。