Experiences with Analytical and Digital Stereoplotters

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.     

Photogrammetry Education for Multidisciplinary Geomatics in China

IntroductionThe word photogrammetry comes from Greekwords photos ( meaning “light”) , gramma( meaning that which is drawn or written) andmetron ( meaning“to measure”) . It originallysignifies measuring graphically by means oflight[1].The development o…     

Photogrammetry education for multidisciplinary geomatics in China

After briefly reviews the history of photogrammetry education in China, the development of undergraduate and graduate program, and the corresponding curricula design are analyzed by use of the data from Wuhan University in which the photogrammetry is awarded as the state-level key discipline. The academic educational program of photogrammetry in universities has trained students to perform tasks in all fields of the photogrammetric profession. In recent years, the nature of photogrammetry is changing and multidisciplinary geomatics are developing very rapidly, the educational program of photogrammetry has also changed in new concepts and structures to adapt very new technologies and the extension of the field. Finally, the prospect of photogrammetry education for the requirements of multidisciplinary geomatics is proposed. The growing interest in fast and accurate 3D spatial data collection (such as city modeling and digital earth) results in the increasing need of photogrammetry as principal tool, photogrammetric courses are therefore requested to be up-to-date and to become one kind of the fundamental professional courses for university geomatics and remote sensing degree programs.     

The Measurement of River Channel Morphology Using Digital Photogrammetry

This paper seeks to review the progress that is being achieved by fluvial geomorphologists in making use of digital photogrammetry for river channel research. Fluvial geomorphology is first placed in a basic historical context from which the failure to make full use of the potential of photogrammetry is noted. A review is then given of the ways in which fluvial geomorphologists are now making use of photogrammetry, recognizing that the development of digital approaches has both made photogrammetry a more cost-effective tool and also introduced a range of new research questions. The main objective of this paper is to demonstrate the importance of these questions and to illustrate some of the ways in which they are being addressed. Special attention is given to the issue of data quality, which is frequently (and perhaps conveniently) ignored.     

Low Cost Digital Rectification on A PC

Digital photogrammetric techniques have opened fresh horizons and have enabled photogrammetry to become a more user friendly tool for a wide range of applications. However cost remains a critical issue, because new digital photogrammetric workstations and their related software are considered expensive. This paper examines the problem of digital rectification and presents low cost solutions involving the use of commercial off the shelf software packages, which include graphics and painting software, image processing tools and a CAD system. Additionally, specially developed software performing vector rectification is described and discussed. All the packages have been used for rectifying digital images and the results are presented. An attempt is also made to assess the accuracy and reliability of the results. Finally, several alternative digital products are presented, mainly concerning the use of the methods described in the restitution of cultural monuments.     

CCD Image System Design And Exploitation: Experiences And Lessons Learned

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.     

An automatic procedure for co-registration of terrestrial laser scanners and digital cameras

Driven by progress in sensor technology, algorithms and data processing capabilities, close range photogrammetry has found a wide range of new application fields over the past two decades. Particularly, the emergence of terrestrial laser scanner has contributed to the close range photogrammetry “popularization” through many promising new applications. Nevertheless, a central issue in many of these developments is the integration of sensor technology with reliable data processing schemes to generate highly automated photogrammetric measurements systems.This paper presents a flexible approach for the automatic co-registration of terrestrial laser scanners (TLS) and amateur digital cameras (DC) to be used effectively in practice. Particularly, the developed approach deals with two different images: a camera image acquired with a DC and a range image obtained with a TLS. To this end, an open-source tool “USAlign” has been developed for testing the different experiments.     

The `Digital Projector': Raytracing as a tool for digital close-range photogrammetry

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).     

Medical photogrammetric measurement: overview and prospects

Since the earliest days of photogrammetry, there have been photogrammetrists who have directed research effort towards medical measurement. Although the specific motivation for these studies has not always been disclosed, it is probably because of the various benefits that photogrammetry can offer to humanity as a painless and non-invasive means of providing medical practitioners with spatial measurement relating to the human body. The intention of this paper is to reflect on the place of the many medical developments within the photogrammetric world. The various photogrammetric applications in medicine are summarised to identify the characteristics of medical photogrammetry, and it becomes evident that medical photogrammetrists have developed a range of body measurements using widely varying photogrammetric techniques, in response to the demands for specialised spatial measurement tools for a wide variety of medical ends. This volume of research activity has made medical measurement a substantial and varied sector of non-mapping photogrammetry. It is also clear that there are numerous challenges to the design of medical photogrammetric systems. They must give paramount consideration to the human patients and their comfort; they must yield not simply spatial data about the body but rather specific medical information. At the same time, it is of concern that non-photogrammetric scientists and engineers have developed medical measurement systems based on both photogrammetric and other optical techniques. Fortunately, photogrammetrists can also contribute to medical problems through their spatial data experiences. It is concluded that the many distinctive challenges mean that medical photogrammetry has not yet been as successful at changing the world as the extensive efforts applied to it suggest, but nevertheless, medical photogrammetry deserves to be recognised as a category of close range photogrammetry which remains a valuable pursuit which should not be abandoned because of any difficulties.     

DMC数字航摄在大比例尺地形图成图中的应用

数字航空摄影具有从测量到成图的全过程数字化的优点。结合1∶2000地形图DMC全数字摄影测量项目对面阵CCD航摄像机用于大比例尺航测成图的基本要求进行了分析研究,提出数字像机的几何标定、数字摄影的质量检验和生产作业规范制订的必要性。     

INDUSTRIAL PHOTOGRAMMETRY: NEW DEVELOPMENTS AND RECENT APPLICATIONS

Over the past decade, photogrammetry has been increasingly applied as a precise three dimensional measuring tool in industrial and engineering works. Analytical photogrammetry is now routinely employed in tasks of measurement as diverse as machine tool inspection and fixture checking, structural deformation monitoring, the provision of control databases to guide industrial robots and the measurement of structures in earth orbit. Traditional photogrammetric techniques and instrumentation are usually inappropriate for industrial work and the development of complete, fully integrated close range photogrammetric systems has recently gained considerable impetus. This paper details some of the significant new developments in industrial photogrammetry, with particular reference to technological advances in the Simultaneous Triangulation and Resection System (STARS) designed by Geodetic Services, Inc. for industrial photograininetry. Practical aspects of industrial measurement are also presented in a review of some of the varying tasks that GSI has carried out in recent years. Emphasis is placed on demonstrating the flexibility, accuracy, reliability and economy of photogrammetry, as well as the progress made in automating this measurement technique.     

High Resolution Still Video Camera for Industrial Photogrammetry

Still video cameras are easy to handle, portable, digital image acquisition devices for close range photogrammetry. They allow fast object recording without being connected to a computer. As an example of the new camera type, the high resolution Kodak DCS200 is presented in this paper, combined with the DPA digital photogrammetric station used for image measurement and object reconstruction. The performance of this three dimensional measurement system is illustrated by calibration results as well as applications to high precision dimensional inspection in industry.     

开放型摄影测量实验基地的设计与建立

摄影测量技术的学习和掌握离不开实验。文中提出建立开放型摄影测量实验基地模式,该基地应该具有如下功能:航空摄影,航测控制测量与调绘,数码相机检校,航测内业处理与测图。在该基地上,学生可以根据摄影测量的学习内容,选择相关实验项目,理论联系实际地学习掌握摄影测量基本理论和方法;学生也可以在基地上自主设计、模拟摄影测量生产过程,训练摄影测量技能,并进行摄影测量试验研究。该实验基地的设计理念和建立模式,将为高校现有摄影测量课程的教学和实验提供一种创新形式。     

PHOTOGRAMMETRIC DIGITISING AND EDITING UNDER COMPUTER CONTROL

Digitising from a photogrammetric instrument can be controlled by a unit specially designed for this purpose, or by a digital control computer. In the latter case, the digitising system is more flexible since alterations and additions to the real-time programs can easily be made to effect different digitising applications. The control computer can also be used in processing the digitised data. The use of such digital control in photogrammetry is as yet limited. The reasons are examined. The characteristics and real-time requirements of a computer controlled digitising system are stated. Different digitising and recording modes, identification numbers and editing arrangements are then given to illustrate the flexibility and limitations of such a system.     

摄影测量和数字图象处理的某些进展

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。     

浅谈VirtuoZo AAT自动空中三角测量的几点体会

随着信息技术和计算机技术的迅速发展,数字摄影测量已取代传统的模拟摄影测量和解析摄影测量,使摄影测量进入数字化时代。VirtuoZo全数字摄影测量系统在测绘工作中的广泛使用,节省了大量的人力,提高了工作效率,减少大量作业时间,提高产品精度。笔者总结了实际作业中常见的问题及解决方法,以供大家参考。     

DIGITAL IMAGE PROCESSING IN PHOTOGRAMMETRY

This review of digital image processing refers to the pioneer work of Helava and Hobrough which has influenced the most recent trends in photogrammetry. The author goes on to discuss aspects of digital image acquisition, storage and display, as well as digital photogrammetric procedures and systems.     

The Z/I Imaging Digital Camera System

Market needs for airborne and spaceborne imagery used in photogrammetry and GIS applications are changing. Fundamental changes in sensors, platforms and applications are currently taking place. Most recently, new high resolution spaceborne sensors have become available. Besides classical photogrammetry, new thematic applications will drive the future image market. Savings in cost and time, together with the need for higher and reproducible radiometric resolution or spectral information will push forward the change from analogue to digital imagery. High resolution satellites will compete with airborne film-based photography and digital camera systems.
With the availability of a digital airborne camera, it is possible to completely close the digital chain from image acquisition to exploitation and data distribution. The key decision regarding the camera design in this case is whether a linear or area array sensor should be used. In view of the high geometric accuracy requirements in photogrammetry, Z/I Imaging has focused development on a digital camera based on an area sensor. An essential aspect of this decision was not only the aerial camera system, but also the entire photogrammetric process to the finished photographic or mapping product. If this point of view is adopted, it becomes clear that the development of a digital camera involves more than simply exchanging film for silicon. Aspects such as data transfer rates, in-flight data processing and storage, image archiving, georeferencing, colour fusion, calibration and preprocessing have the same influence on the economic assessment of a digital camera system. This paper describes current development activities and application aspects of a digital modular airborne camera system.     

颅面整形简易摄影测量系统

近景摄影测量的理论和方法应用于医学领域,是其应用范围的扩展。本文介绍了一种适用于颅面整形的简易摄影测量方法的原理、设备配置、操作方法及数据获取与处理过程,并从多种途径对该方法进行可靠性分析。     

VirtuoZo全数字摄影测量工作站处理数码影像的生产应用

全数字摄影测量主要应用于生产数字地形图及数字地面高程模型（DEM）和数字正射影像图（DOM）。某市及周边地区1：l000地形图航测项目,利用DMC一110摄影仪进行摄影获取的影像数据,使用VirtuoZo数字摄影测量工作站,阐述进行航测内业绘制地形图的全面流程。DMC技术将发挥更大的优势,在数字摄影测量中得到越来越广泛的应用。