共查询到20条相似文献，搜索用时 78 毫秒
1.
P. A. E. Stewart 《The Photogrammetric Record》1986,12(67):5-24
The presence of air and liquid, or two phase flow, in gas turbine oil or fuel systems poses performance analysis problems. Conventional instrumentation is invasive and, by its presence, changes the nature of the flow itself In order to analyse a system comprehensively, a number of non-invasive measurements are preferable. One of the objectives of this project was to determine the feasibility of photogrammetry for this task. The study has fallen into two parts. The first part which has been completed, and is reported here, concerns an investigation of the problems of applying the photogrammetric technique by using stereoscopic images of two phase flow structures and measuring them using calibrated equipment. This has been successful and valuable experience has been gained. Images have been analysed and scientific data obtained. However the nature of the flow is transient and a series of isolated images do not describe the processes and may lead to ambiguities. For this reason, the opportunity provided by John Hadland Ltd. to use the Spin Physics SP2000 High Speed Video system in August, 1984 was taken; using calibrated twin video cameras, the first high speed digital video photogrammetric system was thus operated. Accuracies in three dimensions of better than 0.5 mm are claimed for this experimental work at 1000 fiames s-I. 相似文献
2.
J.-D. Bonjour 《The Photogrammetric Record》1990,13(75):389-405
Several generations of photogrammetric workstations have followed one another since the analytical plotter was developed at the beginning of the 1960s. The outcome of this evolution, resulting from important developments in mini- and microcomputers, is illustrated today by more and more powerful photogrammetric workstations based on distributed processing architecture. This paper introduces present day architectures, as well as hardware and software aspects of the various components of these systems including graphics workstation, real time processor, superimposition system, correlation system and special input/output devices. Finally, an attempt is made to outline the prospects for further evolution. 相似文献
3.
I. J. Dowman 《The Photogrammetric Record》1990,13(75):331-345
This paper reviews the requirements and equipment for the photogrammetric restitution of digital data. Advances in computer technology have made it possible to process and display image data in very fast time; this has made real time movement of images on a display screen a reality and hence, together with stereoscopic viewing, a digital version of the analytical plotter. The necessary components are discussed and the implementations which have been made. The use of parallel processing for additional speed is also discussed and the alternatives of using standard workstations are considered. A system developed at University College London is described and some pointers to the future are provided. 相似文献
4.
W. Bösemann 《The Photogrammetric Record》1998,16(92):187-197
Digital photogrammetric systems have been introduced to solve various measurement problems in industrial applications for many years, ever since high resolution CCD cameras and powerful computer technologies have been available. For a successful implementation of a digital photogrammetric system into the production line, not only does the actual measurement task have to be solved but also a complete integration of the system into the production process usually has to be supplied by the system manufacturer. Three examples of successful implementations of photogrammetric systems for industrial automation and process control are presented in this paper. 相似文献
5.
倾斜摄影测量技术在大比例尺地形图测绘中的应用 总被引：5，自引：0，他引：5
作为国际测绘领域近些年新兴的高新技术,倾斜摄影测量技术已应用于城市快速三维建模中。由于目前常用的大比例尺地形图测绘方法不能同时满足快速成图的时间和成本要求,本文提出了一种利用倾斜摄影测量技术测绘大比例尺地形图方法,充分发挥无人机倾斜摄影测量技术灵活、成本低、高效的优点,倾斜影像可自动生成三维模型和点云,简化了后续绘图工作。评定试验得到的岢岚县大比例尺地形图可知,成果平面精度达到0.140 m,高程精度达到0.150 m,符合大比例尺地形图精度要求,适合快速测绘小区域大比例尺地形图。 相似文献
6.
A case study at the Norwegian Institute of Land Inventory (NIJOS) demonstrates that photogrammetry is an effective method for collecting data for geographical information systems (GIS). The process of establishing a photogrammetric data capture system is explained with special attention devoted to financial and personnel considerations. It is argued that photogrammetric data capture is viable provided that a stereodigitiser is used in conjunction with a modular solution GIS. 相似文献
7.
目前,数字航摄的像控网布设是困扰很多作业单位和技术人员的问题,2012年将要发布实施的行业规范对此仍然缺少实质性的阐述,而数字航摄已经成为航空摄影资料获取的主要手段。本文结合2012年辽宁省开展的1∶10 000基本地形图更新项目,系统地阐述了辽宁省基于数字航摄的像控网布设试验方案的建立及技术要求。 相似文献
8.
Members of the Institute of Engineering Surveying and Space Geodesy, University of Nottingham have been working on a collaborative project with staff of the British Geological Survey and the National Remote Sensing Centre Air Photo Group. During this project, experience of using the Intergraph ImageStation and ERDAS Imagine has been obtained. This paper presents some of these experiences which highlight the merits and limitations of digital photogrammetry at this present time. These are important issues not only for photogrammetrists but also for those coming into contact with photogrammetric operations through their potentially increasing availability in general image processing software. Although based on the authors' experiences, the paper also intends to provide a summary of digital photogrammetric systems and therefore issues are presented in a general way. 相似文献
9.
通过分析倾斜航摄仪的特点,提出一种面向倾斜影像的三维影像分辨率,介绍了3个方向分辨率概念以及推导了斜视影像分辨率的计算公式。结合当前市场上主流的倾斜航摄仪配置,分析了其影像分辨率变化的特点。本文得出的结论对航空摄影设计有重要指导意义,为影像量测精度分析打下了基础。 相似文献
10.
J. E. Juliá 《The Photogrammetric Record》1997,15(90):923-928
A photogrammetric plotting system based upon digitizing tablets, a personal computer and a CAD system is proposed. The system, which is capable of working stereoscopically with the aid of a mirror stereoscope, can perform inner, relative and absolute orientations, and functions like an image space plotter. Simultaneous plotting is achieved because the system runs from Autocad through a program written in Autolisp. In this way, all the CAD editing capabilities can be used and the final map can be transferred without problems into several well known geographic information systems. Applications in terrestrial photogrammetry are also possible. The accuracy depends directly on that of the digitizing tablets and it can be improved significantly with proper compensation of systematic deformations. 相似文献
11.
R. A. Kirwan 《The Photogrammetric Record》1997,15(90):875-881
The main activities carried out by Ordnance Survey Ireland are focused on the production and maintenance of both small and large scale topographic databases. In 1980, photogrammetric methods were extensively adopted to carry out these tasks, based on analytical procedures. A review of operating practices in 1992 led to the introduction of digital systems. The technical complexities of the installation of digital hardware and software in a production environment are reported in this paper. An expanded role for the photogrammetric department also required the acquisition of new skills by its personnel. Experience has shown that further development, based on co-operation between vendor and user, must continue in the digital field. 相似文献
12.
森林植被碳储量的空间分布格局及其动态变化是陆地生态系统碳收支核算的基础。作为森林地上生物量的重要指示因子,森林高度的精确估算是提高森林植被碳储量估算精度的关键。现有研究已证明,由专业星载摄影测量系统获取的立体观测数据可用于森林高度提取,但光学遥感数据最大的问题是受云雨等天气因素的影响严重。区域森林地上生物量产品的生产需要充分挖掘潜在数据源。国产高分二号卫星(GF-2)虽然不是为获取立体观测数据而设计的专业星载摄影测量系统,但其获取的图像空间分辨率可达0.8 m,且具备±35°的的侧摆能力,在重复观测区域可构成异轨立体观测。本文以分别获取于2015年6月20日和2016年7月19的GF-2数据作为立体像对,其标称轨道侧摆角分别为0.00118°和20.4984°,以激光雷达数据获取的林下地形(DEM)和森林高度(CHM)为参考,对利用GF-2立体观测数据进行森林高度提取进行了研究。通过对立体处理得到的摄影测量点云的栅格化得到DSM,以激光雷达数据提供的DEM作为林下地形,得到了GF-2的CHM。结果表明GF-2提取的CHM与激光雷达CHM空间分布格局较为一致,两者之间存在明显的相关性,像素对像素的线性相关性(R2)达到0.51,均方根误差(RMSE)为3.6 m。研究结果表明,在林下地形已知的情况下,GF-2立体观测数据可用于森林高度估算。 相似文献
13.
The use of large-format digital cameras in aerial photogrammetry is leading to great improvements in photogrammetric production. Since they were first introduced about 10 years ago, the technological community has been testing and investigating the conditions under which this major change can be consolidated. But a certain (and understandable) bias may be noticed in the efforts that developers, researchers and clients are undertaking. Almost all of the efforts aim at checking the quality of automated measurements and very little attention has been directed to stereoscopic measurements by human operators, which, nevertheless, still represent an important task that needs to be carried out in the production chain. This paper presents the results from a number of tests (13 operators from a variety of enterprises) performed to check the stereoscopic precision of Vexcel UltraCamD camera images compared with Leica RC30 film images. The main conclusion to be drawn from the empirical data is that stereoscopic precision does not depend on the type of camera. 相似文献
14.
“天绘一号”传输型摄影测量与遥感卫星 总被引：1，自引：1，他引：0
介绍了“天绘一号”卫星的总体方案、技术特点、研制历程和应用概况, 重点介绍了“天绘一号”卫星的技术特点和应用前景, 以便用户了解、熟悉“天绘一号”卫星, 更好使用其各种影像产品, 更好发挥卫星的应用效能。“天绘一号”卫星摄影定位与测图系统采用LMCCD(Line Matrix Charge Coupled Device)测绘体制, 由前视、正视和后视3台全色CCD相机, 3台星敏感器以及1台GPS接收机组成;其中正视相机焦平面上还设计有4个小面阵CCD器件, 用于提高摄影定位的高程精度。卫星摄影测量基高比为1。卫星通过一个高强度、高刚度和高稳定度的测绘光学平台, 将3台测绘相机、3台星敏感器和1台多光谱相机集成为一体, 满足了测绘任务对星敏感器与相机间几何角度关系的高精度及高稳定度要求。在轨测试结果表明, 卫星摄影定位精度优于任务指标要求, 可满足无地面控制点条件下测制全球1:50000比例尺地图要求。 相似文献
15.
C. S. Fraser 《The Photogrammetric Record》1998,16(91):37-50
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. 相似文献
16.
航空摄影测量是当今大比例尺地形图制作使用最多的手段之一,航空摄影测量的生产周期短,精度指标高,成本较低,尤其适宜工期较为紧张的项目.为了确保宜兴“高铁新城”等建设的顺利开展,宜兴市规划局委托作者及其单位组织实施了区域范围内大比例尺地形测绘的项目任务.该项目采用先进的航测技术,综合利用江苏省全球导航卫星连续运行参考站综合服务系统（Jiangsu Continuously Operating Reference Stations,JSCORS）、全球定位系统（Global Positioning System,GPS）、高精度的电子水准仪、JX4等航测设备进行生产,即好又快的完成生产任务,为宜兴高铁新城的建设,提供了优良的技术保障.本文对项目实施过程中涉及到的技术方案设计、主要精度指标及其所取得的社会经济效益进行了探讨,以期为类似航测项目的开展提供借鉴. 相似文献
17.
Y. D. Huang 《The Photogrammetric Record》1998,16(91):97-104
The calibration of phototheodolites such as the Wild P32/T2 combination sometimes involves determining not only the camera interior orientation parameters but also the camera-to-theodolite parameters. The latter become particularly important when the theodolite set orientation parameters are to be used as observations, especially as known quantities for data reduction in subsequent photogrammetric applications. This paper presents experiments to determine these parameters for a Wild P32 camera using a new camera-on-theodolite method, with details of results achieved. 相似文献
18.
Since 1990, the Center for Mapping at Ohio State University has been developing mobile mapping systems to automate and accelerate the collection of digital map data. These systems integrate the global positioning system (GPS) with inertial navigation units and imaging sensors to produce digital geographic data. They are modular and can be installed on various platforms, such as vans, trains and aeroplanes. New developments with the imaging system and the fully integrated data-processing environment are discussed in this article. The stereovision system enables the user to obtain three dimensional co-ordinates of any object in the field of view of the camera. Digital and video images, together with GPS positions, are stored in an object-oriented database, which merges data collected by airborne and terrestrial mapping platforms. Exploiting the enormous amount of information contained in the digital stereoscopic imagery is a challenging topic of current and future research. 相似文献
19.
TAO Chuang LIN ZongjianTAO Chuang Doctoral Candidate School of Information Engineering WTUSM Wuhan China 《地球空间信息科学学报》1998,(1)
We are involved in an embarrassing situation that the limited capa-bility of automated feature extraction in digital photogrammetric systems cannotsatisfy the increasing needs for rapid acquisition of semantic information for appli-cations.Facing this challenge,a new tactic,Human-Computer Collaborative（HCC）tactic,and a corresponding new method,Operator-Object Directed（OOD）method,are proposed for the design of a system for feature extractionfrom large scale aerial images.We hold that in almost all technical complex sys-tems,full automation will be neither technically feasible nor socially acceptable.The system should be designed to optimize through the cooperative operation withtwo agents in the system:the human and the computer. 相似文献
20.
R. Farrand 《The Photogrammetric Record》1967,5(29):373-380
Some applications of photogrammetric techniques do not require the high standard of accuracy in instrumentation which we have come to associate with air survey. The comparator now described provides a simple solution to a particular problem. It requires neither a skilled operator nor stereoscopic vision, and could be used by the average office draughtsman. 相似文献