共查询到20条相似文献，搜索用时 31 毫秒
1.
G. R. Hoffman 《The Photogrammetric Record》1995,15(86):205-216
The use of digital imagery, acquired through charge-coupled devices (CCDs) either by the scanning of hard copy film or direct capture through the use of a CCD camera, has fundamentally changed the photogrammetric environment. In order to fully exploit these digital image data, the photogrammetrist must employ system design, implementation philosophies and processing methodologies different from those of traditional film based photogrammetry. It is now possible for these new photogrammetric systems to be operated from low cost, high performance PC and Macintosh class commercial hardware, using vendor supplied software for user developed applications. This paper explores lessons learned and experiences gained from low cost, digital photogrammetric system development and CCD image exploitation. Examples and discussion presented in this paper include: (1) integration of user developed applications with commercial hardware and software; (2) user interface design; (3) validation of processing algorithms within the digital image domain; (4) system calibration; (5) digital image data handling, management and storage; and (6) image data compression. The film based photogrammetric system provides the point of departure to digital photogrammetry. Technical knowledge, system design and implementation and CCD image exploitation provide the experience. 相似文献
2.
In this paper, different ways of performing large scale mapping of built up areas are discussed. Emphasis is placed on large scale representation through digital orthophotographs as the visualization medium of the real world. In an application, the process of creating perspective views of an orthophotograph draped on the digital terrain model of the study area is described; these views include the blocks of the built environment as three dimensional objects. The cartographic product is derived from a pair of overlapping aerial photographs processed through photogrammetric and GIS software packages. Finally, the perspective view of the digital orthophotograph is assessed as a large scale visualization tool for the communication of spatial information. 相似文献
3.
Stereoscopic softcopy photogrammetric systems were originally as expensive as analytical stereoplotters, which prohibited their use in most small production firms. At the lower end of the cost spectrum, the functioning of these systems has previously been somewhat limited. Advances in computing technology and software architecture have now made an economic replacement of analogue stereoplotters a reality. A reasonably priced, high performance, off the shelf production solution is now possible on standard PC hardware. This paper provides a comparison of analogue and digital photogrammetry for a production work flow, commencing after scanning the films and progressing through project set up, orientations, stereodisplay and feature collection, DTM collection and editing, finally ending prior to orthophotography production. The underlying breakthrough software architecture making an effective digital system possible at moderate cost is described in detail and the benefits of such a system compared with analogue plotters are highlighted. 相似文献
4.
陈鹰 《武汉大学学报(信息科学版)》1988,(4)
本文从王之卓教授关于“数字图象处理将是摄影测量的一个新的作业领域”的观点出发,介绍了用数字图象处理的方法解决摄影测量问题方面的某些进展,主要是:快速数字微分纠正,影象增强与镶嵌,数字立体正射影象图,LANDSAT和SPOT卫星图象的参量估计与星历数据的利用。 相似文献
5.
F. Ackermann 《The Photogrammetric Record》1984,11(64):429-439
A procedure for digital image correlation is described which is based on least squares window matching. The immediate aim is high precision parallax assessment, point transfer, and point measurement. Experiments and theory have confirmed the high accuracy potential of the method. By implementation of charge coupled device (CCD) video cameras in an analytical plotter, an experimental hardware and software configuration has been established with which the operational on line application of digital image correlation for conventional photogrammetric measuring tasks can be tested. First results of calibration and performance of the system are presented. They allow optimistic conclusions as to the further development and practical application of digital image processing in photogrammetry. 相似文献
6.
This paper describes work undertaken to measure deformation of a pavement within the Newcastle University Rolling Load Facility (NUROLF). Precise three dimensional measurements of the pavement have been produced from stereo-imagery taken with diVerent cameras, using both analytical and digital photogrammetric instrumentation. The photogrammetric measurements, and those from the existing system consisting of an array of linear voltage displacement transducers, have been compared with measurements produced using a digital level. Encouraging results have been achieved and photogrammetry has been shown to be capable of producing a similar accuracy to the existing system. There are many advantages associated with a photogrammetric survey but attempts to establish a permanent, automated photogrammetric system for the rolling load facility at a reasonable cost have so far been unsuccessful. It is anticipated that, with the falling cost of high resolution digital sensors, such a system will soon be possible. 相似文献
7.
Manuel A. Aguilar Fernando J. Aguilar Francisco Agüera 《The Photogrammetric Record》2005,20(112):335-350
Generating maps of small areas using conventional aerial photography is of great interest for small engineering firms. The main problem is the high cost of the sophisticated digital photogrammetric workstations usually employed. In this paper, a low-cost close range photogrammetric software package is used to measure the three-dimensional coordinates of points on the land surface from a photogrammetric flight at a scale of approximately 1:5000. Furthermore, the influence of the type of scanner used to digitise photographs (consumer-grade or photogrammetric scanner), the resolution of the digital images and the number of control points required are examined. The root mean square errors obtained at the check points, using a low-cost close range software package, scanning aerial images with a photogrammetric scanner and 24 ground control points, were around 116 mm for X and Y coordinates, and 191 mm for Z. These levels of accuracy allow the generation of planimetric maps at a scale of 1:1500 and topographic maps with a contour interval of around 1 m. When the images were scanned with a consumer-grade scanner, the root mean square errors were around 150 mm for X and Y, and 271 mm for Z. 相似文献
8.
Using a multidisciplinary project studying surging glaciers in Svalbard as a reference, this paper examines some of the ways in which photogrammetry can be used as a research tool by glaciologists. Photogrammetric compilations of two of the glaciers under study were produced from 1990 aerial photography. Photogrammetry was regarded primarily as a source of digital elevation models in this project, rather than as a cartographic tool. Problems encountered in applying photogrammetry to the arctic terrain are considered and a methodology devised to ameliorate these problems by maximizing the available data is described. The results of the photogrammetric work are presented and difficulties in quantifying the accuracy of the photogrammetric data are examined. Examples of the ways in which the photogrammetrically derived digital data have been used for glaciological analysis and visualization are discussed. 相似文献
9.
This paper discusses the use of near vertical aerial photographs archived onto Kodak Photo CD in the production of a digital elevation model of the Isle of May, Scotland. Control for the survey was obtained using differential GPS receivers and the photogrammetric processing was carried out using low cost PC hardware and software. The elevation model is being used in a GIS to enable the spatial analysis of the island's seal population. 相似文献
10.
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
11.
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
12.
《ISPRS Journal of Photogrammetry and Remote Sensing》1999,54(1):35-40
In close-range applications, digital methods are increasingly used. In addition to the software and techniques which were adopted from aerial photogrammetry, new strategies for the restitution and presentation of digital data have been developed. The `Digital Projector' is a strictly photogrammetric approach using raytracing techniques and off-the-shelf software to provide 3D models with complete texture. It works regardless of the shape of the object while allowing digital presentation (`photomodels') with numerous derivative results (e.g., orthoimages and animations). 相似文献
13.
Some exciting developments have been made recently, in the field of digital image rectification, which are of interest to both the photogrammetric specialist and non-specialist. This paper outlines the technical processes involved in generating digitally rectified images, as well as raising some of the issues that are becoming apparent when applying this modern technology to archaeological and architectural presentation. 相似文献
14.
D. P. Chapman 《The Photogrammetric Record》2000,16(95):763-779
As the performance of megapixel digital imaging systems continues to improve, the rapid growth of high-end consumer markets drives prices ever lower. When such cameras are married with emerging, desktop "photogrammetric" software packages, the close range photogrammetric community is faced with many new challenges and opportunities. The dramatic changes in the technological arena are matched by a rapidly changing business environment in which concepts such as "Partnering" and "Supply chain management" have become key themes. As organizations of all sizes seek to thrive within this new business landscape, there appears to be a willingness to think more flexibly about the client-supplier relationship and the sharing of risks and rewards. This, in turn, has encouraged the development of highly customized measurement solutions across a wide range of market sectors. In each of these solutions the emphasis is not on a generic photogrammetric product, but on a highly tailored system tightly coupled to existing workflows, and focused on the specific needs of the client. Such systems pose particular challenges to their designers, since they are frequently operated by users with relatively little photogrammetric background and yet must always meet the challenging requirement of producing an output which is "fit for purpose". Thus this paper hopes to show how novel megapixel imaging systems can be configured to deliver flexible measurement systems capable of millimetric level accuracy within the challenging engineering environments typical of the nuclear and process industries (hence the microsievert component of the title). 相似文献
15.
Joint development work by LH Systems and Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Center) has produced encouraging results using forward, nadir and backward looking linear arrays on the focal plane to provide panchromatic imagery and geometric information, supplemented by further arrays to acquire multispectral imagery suitable for both high precision photogrammetric mapping and image processing for interpretative purposes. The geometric characteristics of line scanner imagery necessitate line-by-line rectification for aircraft tilts and shifts. Satisfactory execution of this process is enhanced by using supplementary data from high performance, on-board GPS and inertial measurement systems. Similarly, high demands are placed on other sub-systems, such as the camera mount, lens, electronics and storage technology. In addition to rectification for aircraft tilts and shifts, rectification for terrain characteristics is also required in order to generate colour and false colour composite images, since the various multispectral arrays are in different places on the focal plane. The special geometry affects triangulation. Thereafter, the imagery can be processed using existing software packages from both photogrammetry and remote sensing.
The concept has been demonstrated in several successful test flights and the production model is scheduled for market introduction at the ISPRS Congress in July 2000. The imagery from the new sensor will fulfil many market requirements between the highest resolution film imagery (<0.1 m) and high resolution space imagery (1m to 10 m). The sensor's unique blend of multispectral information with high quality geometric information will give rise to numerous new applications. 相似文献
The concept has been demonstrated in several successful test flights and the production model is scheduled for market introduction at the ISPRS Congress in July 2000. The imagery from the new sensor will fulfil many market requirements between the highest resolution film imagery (<0.1 m) and high resolution space imagery (1m to 10 m). The sensor's unique blend of multispectral information with high quality geometric information will give rise to numerous new applications. 相似文献
16.
J. Dold 《The Photogrammetric Record》1998,16(92):199-212
In the past few years the automation of digital industrial photogrammetric systems has increased dramatically. Due to digital image processing software, coded targets and automatic matching methods, a huge number of photogrammetric measurement tasks can be fully automated. In many cases a "one button click" is enough to provide the three dimensional co-ordinates of measured points without any manual interaction, immediately after acquiring the images. The technology of intelligent cameras is a logical step towards automated photogrammetric measurements. An intelligent camera, which has an integrated computer, analyses the image immediately after it is taken. This technology provides not only a much shorter processing time for the images but also more control over the measurement process just when it is needed, during image acquisition. This takes place in the form of real time feedback.
This paper describes the role of a digital intelligent camera in the automation of an industrial photogrammetric measurement system and gives an overview of existing automation techniques in industrial photogrammetry. As an example of an intelligent camera, the performance of the new INCA digital intelligent camera, developed and manufactured by Geodetic Services, Inc. (GSI) and distributed by Leica, is described. 相似文献
This paper describes the role of a digital intelligent camera in the automation of an industrial photogrammetric measurement system and gives an overview of existing automation techniques in industrial photogrammetry. As an example of an intelligent camera, the performance of the new INCA digital intelligent camera, developed and manufactured by Geodetic Services, Inc. (GSI) and distributed by Leica, is described. 相似文献
17.
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
18.
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
19.