ALBERT

Notes: 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.

Notes: Detailed understanding of the processes which control river bank erosion requires high resolution information concerning temporal changes in bank morphology. This paper describes the successful use of digital photogrammetry to extract high resolution digital elevation models (DEMs) from terrestrial oblique stereopairs of rapidly eroding river banks, using the commercial software package Erdas Imagine. This software was developed for use with aerial photography and satellite imagery; problems relating to the use of oblique terrestrial images are discussed and solutions presented. Photography was acquired using semi-metric cameras, mounted on tripods and positioned about 15m from the eroding bank. Data for DEM point spacings of 20mm were obtained, with accuracies of approximately ±12mm in depth. Digital photogrammetry can permit faster analysis, provide better accuracies and involve less ground disturbance than conventional methods of monitoring river channel change. Most importantly, DEM generation is considered to be more useful than traditionally acquired points or profiles for landform monitoring strategies.

Notes: This paper assesses the feasibility of estimating water levels using digital photogrammetry. A common problem during an extreme flood event is that automated water level recorders do not record the highest water levels, as a result of instrument malfunctioning. This paper explores two possible solutions to this problem based upon data acquired using synoptic remote sensing methods. The first method requires: (a) high-resolution elevation data (for example, in the form of a digital elevation model for the floodplain); and (b) information on the planimetric position of the maximum flood extent, such as from debris lines (known as wrack lines) visible on aerial imagery flown after the event. The planimetric data can then be used to segment the topographic data in order to identify water level elevations. The second method uses a digitial photogrammetric approach and is suitable where no topographic data are available, but aerial imagery is available, flown after the event. Provided this imagery is of the right scale, digital photogrammetric analysis may be used to identify the elevations of wrack lines visible on the imagery. In this paper, the second of these options is compared with the first. The research shows that desktop photogrammetric methods, using 1:4500 scale imagery, can yield water level estimates that are precise to ±0·147 m, on the basis of check data obtained from lidar data. This is a worst possible estimate of the acquired precision given uncertainties in the lidar data. When compared with the first option, based upon segmenting lidar data using flood outlines, the photogrammetric approach was found to be preferable given both the quality of the lidar and uncertainties over how to segment it.

Notes: Aerial photography for archaeology has been developing its approaches and techniques over the past 100 years so that it now integrates the results of reconnaissance with extensive interpretative and analytical surveys. This paper introduces the philosophy and approach of the English Heritage (EH) Aerial Survey team, covering aerial reconnaissance and the National Mapping Programme (NMP), as well as the potential developments and opportunities in Europe. In the 1980s there was a debate over the nature of the evidence derived from aerial photographs, especially how to describe archaeological features. As part of NMP a classification and recording system has been devised which meets most of the users’ needs, be they national organisations, county archaeologists, commercial contractors or university-based researchers. The maps and records produced by NMP are used to further our understanding of the past human settlement in England, not only at the individual site level, but also in regional or landscape contexts. This paper provides an overview of the current progress of NMP and acts as an entrée for explaining the current research and recording of archaeological landscapes throughout Europe. Recent developments in Britain and Europe have provided the opportunity for a greater priority to be given to aerial survey and accelerating programmes of mapping. In Europe the ending of the cold war has allowed greater access to aerial photographs and the possibility of beginning new reconnaissance, as well as introducing new forms of remote sensing. All these developments have led to a transformation of our understanding of prehistoric, Roman and medieval archaeology.

Notes: The design and performance of a computer assisted system for aerial triangulation, mapping and digital data output are described with examples of practical applications. The economic and human considerations are reviewed after three years' experience with the system in production.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn décrit le plan et le fonctionnement d'un système d'ordinateur assisté pour la triangulation aérienne, le rendement des données digitales et cartographiques, avec exemples de leurs applications pratiques. On explore les considérations économiques et humaines après 3 ans d'expérience avec le système en production.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungAuf bau und Leistungsfähigkeit eines rechnergestützten Systems zur Aerotriangulation, Kartenherstellung und digitalen Datenausgabe werden unter Angabe von Beispielen zur praktischen Anwendung beschrieben. Nach dreijähriger Produktionserfahrung wird ein Überblick über ökonomische und menschliche Probleme gegeben.

Notes: This paper considers a few aspects of the influence which Professor E. H. Thompson had upon the development of analytical techniques in photogrammetry, a field in which he was a prolific leader. The writer gives a purely personal view of Thompson's influence on his own studies, mainly in analytical aerial triangulation, over the period of their association.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméCette communication considère quelques aspects de l'influence qu'eut le professeur E. H. Thompson sur le developpement des techniques analytiques en photogrammétrie, un domaine dans lequel il fut un leader proliphique. L'auteur donne une vue purement personnelle de l'influence de Thompson sur ses propres études, en particulier sur la triangulation aérienne analytique, au cours de leur association.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungIm Beitrag werden einige wenige Gesichtspunkte bezüglich des Einflusses, den Prof. E. H. Thompson auf die Entwicklung analytischer Verfahren in der Photogrammetrie ausübte, einem Gebiet auf dent er eine herausragende Persönlichkeit war, erörtert. Dabei wird eine rein persönliche Ansicht bezüglich des Einflusses von Thompson auf die Arbeiten des Autors wiedergegeben, insbesondere in der analytischen Aerotriangulation während der Zeit, wo sie gemeinsam gearbeitet haben.

Notes: This article provides a brief description of the functions and capabilities of an image generating system developed by Linotype-Paul Limited for the Royal Aircraft Establishment, Farnborough.〈section xml:id="abs1-2"〉〈title type="main"〉Résumé Cet article donne une courte description des fonctions et des possibilités d'un système generateur d'images developpé par Linotype-Paul Limited pour Royal Aircraft Establishment, Farnborough.〈section xml:id="abs1-3"〉〈title type="main"〉Zusammenfassung Kurze Beschreibung der Funktionen und Fähigkeiten eines bilderzeugenden Systems, das bei der Linotype-Paul Limited für das Royal Aircraft Establishment in Farnborough entwickelt wurde.

Notes: Problems are sometimes encountered during the relative orientation of close range photography which has a limited usable format and a large Z range. Computer simulations and practical tests with both a comparator and a plotting instrument are used to investigate the problems and possible inaccuracies. Systematic errors in the photogrammetric model are revealed.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn rencontre souvent des difficultés lorsqu'on forme un modèle avec des clichés pris à courte distance, à format réduit et lorsque l'objet présente quelque profondeur. On a approfondi ces problèmes en utilisant conjointement simulations et essais pratiques; on a prouvé ainsi que les déformations du modèle étaient systématiques.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungMitunter ergeben sich bei der relativen Orientierung von Nahbereischsbildern Probleme, weil das nutzbare Bildformat klein und der z-Bereich gross sind. Mit Hilfe von Computer-Simulationen und praktischer Tests mit einem Komparator bzw. einem Auswertegerät wurden die Probleme und mögliche Ungenauigkeiten untersucht. Dabei wurden systematische Fehler in dem photogrammetrischen Modell aufgedeckt.

Notes: Three investigations of the suitability of photogrammetry as a method of measurement are described, in the fields of marine, mechanical and structural engineering. Analytical solutions for a single model, a strip and a block of photographs are discussed.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn décrit trois tentatives de recours à la photogrammétrie en métrologie industrielle, dans les industries de la marine, de la mécanique, et des structures métalliques. On discute l'intérêt des solutions analytiques pour le couple, la bande ou le bloc de photos.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungBeschreibung von drei Untersuchungen bezüglich Eignung der Photogrammetrie als Messverfahren im Schiffbau, im Maschinenbau und im Bauwesen. Diskussion analytischer Lösungen für das Einzelmodell, die Bildreihe und den Block.

Notes: The concept of optimum interpolation is briefly explained. The use of polynomial and non-polynomial stepwise regression for obtaining optimum or near optimum interpolation is illustrated. Least squares collocation is presented as an advanced method for optimising stepwise regression whenever the latter does not achieve desired optimum interpolation for given terrain. A Fortran IV program, written to illustrate an optimum interpolation algorithm using stepwise regression and collocation, is found to produce better results than existing interpolation methods. Other applications of such an algorithm are also discussed.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn expose brièvement le concept d'interpolation optimale, ainsi que les méthodes d'approximation polynomials ou autres qui permettent de la réaliser localement au mieux. On présente la collocation comme une méthode permettant de parachever l'interpolation; on a trouvé effectivement, avec un programme écrit en Fortran IV, que les résultats obtenus ainsi étaient meilleurs. On envisage aussi d'autre types d'applications de cet algorithme.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungKurze Erläuterung des Begriffs der optimalen Interpolation. Skizzierung der Anwendung von schrittweiser Regression mit Hilfe von Polynomen oder anderen Verfahren zur Ermittlung optimaler oder genähert optimaler Inter-polationen. Die Kollokation nach kleinsten Quadraten wird als verbesserte Methode zur Optimierung der schrittweisen Regression dargestellt, wenngleich letztere keine optimale Interpolation für ein gegebenes Gelände liefert. Ein Rechenprogramm in Fortran IV, das zur Veranschaulichung eines optimalen Interpolations-Algorithmus mit Hilfe der schrittweisen Regression und Kollokation geschrieben wurde, lieferte bessere Ergebnisse als vorhandene Interpolationsmethoden. Andere Anwendungen eines solchen Algorithmus werden ebenfalls erörtert.

Notes: A panel of speakers, knowledgeable in the problems of photogrammetry in the Third World, led a discussion which considered the place of sophisticated photogrammetric equipment in the Third World, problems of technician and management training, the desire for self reliance, and the needs of map revision.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméUne confrontation entre photogrammètres sur le sujet photogrammétrie et tiers-monde; équipement, instruction des techniciens, problèmes d'organisation, désir d'autonomie, révision des cartes.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungEin Forum von Kennern der Probleme der Dritten Welt führte eine Diskussion über den Platz moderner Geräteausrüstungen in diesen Ländern, über Probleme der Ausbildung von Technikern und Führungskadern und erörterte den Wunsch nach Selbstbestätigung und die Notwendigkeit zur Laufendhaltung von Karten.

Notes: The problems associated with the depiction of a particular irrigation area by both line map and orthophotomap are described and the results compared.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméDes problèmes soulevés par la description d'une aire d'irrigation à l'aide d'une carte ou d'une ortho-photocarte: comparaison des résultats.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungBeschreibung der Probleme, die bei Auswahl sines Bewässerungsgebietes an Hand von Strich- und Orthophotokarten auftraten und Vergleich der Ergebnisse.

Notes: In 1981, a metric camera will be launched into space on a European Space Agency Spacelab mission. This paper examines the specification for this mission and the expected results. Other developments are also considered. These include the American large format camera and long focal length imaging systems.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméEn 1981, une chambre métrique sera lancée dans l'espace (mission Spacelab de l'organisation européenne spatiale). On examine ici les buts et les résultats attendus, ainsi que de futurs développements; chambre américaine à grand format, systèmes à longues focales.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungIm Jahre 1981 soll sich an Bord des Europäischen Spacelab-Satelliten eine Messkammer befinden. Im Artikel werden die Anforderungen an dieses Projekt und die zu erwartenden Ergebnisse diskutiert. Desgleichen werden auch andere Entwicklungen, worunter sich die amerikanische Grossformat-Kammer und langbrennweitige Systeme befinden, erörtert.

Notes: A close range photogrammetric system, developed around a 35 mm Pentax camera fitted with a wide angle lens (f = 21 mm) and an early Zeiss wide angle multiplex, has proved useful for both instruction and research. Student exercises involve all phases of photogrammetry, from establishing ground control to plotting, and permit the integration of useful statistical routines for data analysis. Research applications have centred on the topographic mapping of microscale landforms at scales of 1: 1 to 1: 10 with accuracies of ± 1 mm to ± 5 mm.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméUn système mis au point pour la photogrammétrie à courte distance, et dont les éléments essentiels sont une chambre Pentax (f = 21 mm) et un Zeiss grand angle multiplex, a fait la preuve de son utilité tant pour l'instruction que pour la recherche. Les exercices proposés aux étudiants comportent toutes les phases réelles, depuis l'établissement d'un canevas d'appui jusqu'à la restitution. Les applications à la recherche sont centrées sur la cartographie des microreliefs à des échelles variant de 1: 1 à 1: 10 avec des exactitudes variant de ± 1 mm à± 5 mm.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungEin Aufnahme- und Auswertesystem zur Nahphotogrammetrie, bestehend aus einer 35 mm Pentax Kamera, die mit einem Weitwinkelobjektiv (f= 21 mm) ausgerüstet war, und ein alter Weitwinkel-Multiplex von Zeiss haben sich bei der Ausbildung und Forschung als nützlich erwiesen. Bei den studentischen Übungen werden alle Phasen der Auswertung von der Passpunktbestimmung im Gelände bis zur Stereokartierung erfasst, wobei es auch möglich ist, statistische Tests zur Datenanalyse einzubeziehen. Die Forschungsarbeiten konzentrierten sich auf die Herstellung topographischer Karten von kleinmassstäbigen Geländeformen in den Massstäben 1: 1 bis 1: 10 mit Genauigkeiten von ± 1 mm bis ± 5 mm.

Notes: Stimulated by promising overseas results with colour aerial photography and encouraged by its potential for solving local problems, the Forests Commission, Victoria, embarked on a series of trials with colour photography in 1965. Early results showed great promise and resulted in further work. This paper describes the methods and results of 70 mm and 35 mm trials concerned with the evaluation of various photographic films. An important aim of the study was to build up a working knowledge of the techniques of using aerial films other than conventional panchromatic black and white and to assess their value under Australian conditions.〈section xml:id="abs1-2"〉〈title type="main"〉Résumé Stimulés par les résultats obtenus outre-mer en matière de photo aérienne en couleur, et disposant d'un potentiel adéquat, le Forests Commission, Victoria a entrepris en 1965 une série d'essais, dès le départ très encourageants. On décrit ici les essais d'évaluation de différents types de film (70 mm et 35 mm); le but était de se familiariser avec la couleur et d'en étudier les conditions d'emploi sous les latitudes australiennes.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungAngeregt durch erfolgversprechende Ergebnisse mit Farbluftbildern in Übersee und ermutigt durch die Möglichkeiten zur Lösung lokaler Probleme unternahm die Forstkommission in Viktoria (Australien) eine Reihe von Versuchen mit Farbaufnahmen im Jahre 1965. Diese Versuche erwiesen sich vielversprechend und wurden fortgesetzt. Im Artikel werden die Verfahren und Ergebnisse von Versuchen mit 70 mm und 35 mm Aufnahmen zur Bewertung verschiedener photographischer Materialien beschrieben. Ein wichtiges Ziel der Untersuchung war das Erlangen von Kenntnissen über die Verfahren zur Verwendung nichtkonventioneller panchromatischer Schwarz-Weiss-Filme und deren Bewertung unter australischen Bedingungen.

Notes: This paper revisits the basic mathematical formulation of ortho-image (digital orthophoto) generation. The main objective is to provide an approach for predicting the accuracy of an ortho-image, according to the accuracy of the digital elevation model (DEM), control points and image measurements, the configuration of fiducial, tie and control points, and the ground slope. The approach is based on applying the well-known law of error propagation to the mathematical model of ortho-image generation. Although it may seem intuitive for professionals in the field of photogrammetry, such an approach is essential in the era when specialists in other fields use off-the-shelf software packages for ortho-image generation. Simulations with the derived approach show that the accuracy of the ortho-image is more sensitive to errors in image measurement of fiducial, tie and control points and ground coordinates of control points, than to DEM errors. Non-standard configurations of fiducial, tie and control points further impair the accuracy. In addition, certain combinations of point location and ground slope might lead to unacceptably large error on the ortho-image.

Notes: The attempts by A. S. Macdonald in the late 1980s and by J. A. Allan in the mid-1990s to integrate the UK societies and professional organisations within the spatial science field are described. The Photogrammetric Society, noting a long-term decline in its membership, set up an internal working group in 1997 to consider the future of the Society. A lengthy questionnaire to all individual members produced a 57% response and mandatory support for renewed action on greater inter-society cooperation.A further effort to produce a wide amalgamation of bodies in the UK spatial science field on the Macdonald/Allan models failed for lack of support nationally. As a smaller step, perhaps to be extended later, a merger with the Remote Sensing Society was eventually agreed. The subsequent lengthy and delicate negotiations necessary to bring about a successful merger between these two mature, independently minded learned societies are described. The two societies were formally merged on 1st April 2001.The author was a member of both the Photogrammetric and the Remote Sensing Societies and chaired the External Affairs Committee of the Photogrammetric Society preceding the merger.

Notes: Professor F. Ackermann was specially invited to contribute an article to mark the 50th issue of The Photogrammetric Record. As the only photogrammetrist to have received both the Brock and von Gruber awards of the International Society for Photogrammetry, he is particularly well qualified to express his views on the past and future development of photogrammetry.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméLe professeur Ackermann a été invitéàécrire un article pour fêter la sortie du 50ème numéro. Seul photogrammètre cumulant médaille de Brock et médaille de von Gruber, il était particulièrement qualifié pour juger du passé et préjuger de l'avenir de la photogrammétrie.〈section xml:id="abs1-3"〉〈title type="main"〉Zusammenfassung Professor Ackermann wurde gezielt eingeladen, um einen Beitrag anlässlich des Erscheinens der 50. Ausgabe des Photogrammetric Record beizusteuern. Als einziger Photogrammeter, der sowohl den Brock- als auch v. Gruber-Preis der ISP erhalten hat, ist er besonders qualifiziert, seine Ansichten über Vergangenheit und Zukunft der Photogrammetrie zu äussern.

Notes: This paper presents the prototype of a low-cost terrestrial mobile mapping system (MMS) composed of a van, two digital video cameras, two GPS receivers, a notebook computer, and a sound frame synchronisation system. The imaging sensors are mounted as a stereo video camera on top of the vehicle together with the GPS antennae. The GPS receivers and the notebook computer are configured to record data referred to the vehicle position at a planned time interval. This position is subsequently transferred to the road images. This set of equipment and methods provide the opportunity to merge distinct techniques to make topographic maps and also to build georeferenced road image databases. Both vector maps and raster image databases, when integrated appropriately, can give spatial researchers and engineers a new technique whose application may realise better planning and analysis related to the road environment. The experimental results proved that the MMS developed at the São Paulo State University is an effective approach to inspecting road pavements, to map road marks and traffic signs, electric power poles, telephone booths, drain pipes, and many other applications important to people's safety and welfare. A small number of road images have already been captured by the prototype as a consequence of its application in distinct projects. An efficient organisation of those images and the prompt access to them justify the need for building a georeferenced image database. By expanding it, both at the hardware and software levels, it is possible for engineers to analyse the entire road environment on their office computers.

Notes: In 1976 the author succeeded the late Professor E. H. Thompson as editor of The Photogrammetric Record, having been assistant editor since 1965. Here he sets out, on the occasion of its 50th issue, some of the details which fashion the content and appearance of the Record.〈section xml:id="abs1-2"〉〈title type="main"〉Résumé En 1976 l'auteur devient, après feu le professeur Thompson, rédacteur en chef du Photogrammetric Record; il était son adjoint depuis 1965. A l'occasion du 50eme numéro, il expose les conceptions qui président au contenu et à l'aspect de la revue.〈section xml:id="abs1-3"〉〈title type="main"〉Zusammenfassung Im Jahre 1976 wurde der Autor Nachfolger von Professor E. H. Thompson als Redakteur der Zeitschrift Photogrammetric Record, nachdem er schon seit 1965 als stellvertretender Herausgeber tätig war. Anlässlich des Erscheinens des 50. Heftes beleuchtet er einige Einzelheiten, die Inhalt und Aufmachung des Record formen.

Notes: Lidar and photogrammetry have both been evaluated for detecting shortterm coastal change using the Black Ven mudslide, Dorset as a case study. A lidar-generated digital elevation model (DEM) was obtained and initially compared with a DEM generated using available 1:7500 scale aerial photography and automated digital photogrammetry. The quality of these two data sets was assessed using a third DEM, derived using a total station and conventional ground survey methods. The vertical accuracies (rms error) of the lidar and photogrammetry were 0.26m and 0.43m respectively, although both data sets displayed a tendency to generate heights slightly lower than the elevation of the terrain surface. The quality of the two data sets was then assessed with respect to local slope angle. The accuracy of photogrammetrically derived elevations varied with slope and more so than in the case of lidarFrom these basic tests, lidar has proved to be more accurate than photogrammetry for soft-cliff. monitoring. Further research is required to establish whether this trend is applicable to other data sets and specifically for photogrammetric data acquired using larger scale imagery

Notes: An understanding of the evolution of cracks in concrete structures due to long term natural deformation is important to civil engineers, but quantitative measurements can be difficult to make. However, digital imaging offers a potential solution. This short paper illustrates the operational application of automated image processing techniques for accurate, multi-temporal crack measurements. The first part of this paper provides an overview of automatic feature extraction, essential for automatic crack detection. The latter part describes the methods developed for detecting and measuring cracks. Due to the long term nature of the application, operational results have yet to be finalised, although sample results are presented

Notes: Antarctica, with its vast areas of snow, presents unusual problems to the photogrammetrist and the cartographer. The paper describes two methods used by the Directorate of Overseas Surveys to overcome these problems and to produce 1: 250 000 scale mapping. The first part of the paper gives an account of the use which was made of tricamera photography, with particular emphasis on the adaptation of Williamson multiplex equipment to operate with the oblique elements of tricamera photography. The second part of the paper, after outlining some of the fundamental principles of ERTS 1 (Landsat) imagery, goes on to describe the application of these principles when utilising imagery in the production of much needed image and line maps of Antarctic areas. Accuracies achieved by the two methods and their relative economies are discussed.〈section xml:id="abs1-2"〉〈title type="main"〉Résumé L'Antarctique, avec ses vastes étendues de neige, pose des problèmes particuliers au photogrammètre et au cartographe. On décrit ici deux méthodes utilisées par le Directorate of Overseas Surveys pour produire la carte au 1: 250 000. La première consiste à employer pour la prise de vues une chambre triple, associée pour la restitution à un multiplex Williamson modifié pour I'exploitation des vues obliques. La deuxième consiste en une tentative d'utilisation des images satellitaires ERTS 1 (Landsat). On analyse Vexactitude et le prix de revient des deux méthodes.〈section xml:id="abs1-3"〉〈title type="main"〉Zusammenfassung Die Antarktis bietet dem Photogrammeter und Kartographen mit ihren riesigen Schneeflächen ungewöhnliche Probleme. Im Artikel werden 2 vom Directorate of Overseas Surveys angewandte Verfahren beschrieben, um diese Schwierigkeiten zu überwinden und Karten im Massstab 1: 250 000 herzustellen. Im 1. Teil der Arbeit wird über die Anwendung von Dreikammer-Aufnahmen berichtet, wobei insbesondere auf die Adaption des Williamson-Multiplexgerätes zur Auswertung der dabei mit aufgenommenen Schrägbilder eingegangen wird. Im 2. Teil des Artikels werden die grundlegenden Prinzipien der ERTS (Landsat)-Aufnahmen skizziert und deren Anwendung zur Herstellung der dringend benötigten Bild- und Linienkarten antarktischer Gebiete beschrieben. Die mit den beiden Verfahren erzielten Genauigkeiten und ihre relative Wirtschaftlichkeit werden diskutiert.

Notes: This paper gives the results of an investigation into the use of different sampling rates and models for the interpolation of perspective-centre coordinates in GPS-assisted aerial triangulation. Industry-standard models and rigorous signal reconstruction filtering have been implemented for two largescale photogrammetric blocks. GPS sampling rate was found to have the most impact on bundle adjustment results in terms of the perspective-centre residuals. However, the accuracy of object-space point coordinates was found to be invariant to both GPS sampling rate and interpolation method

Notes: The author has been involved in the manufacture of photogrammetric instruments for nearly 30 years. In particular, he was associated with the Thompson-Watts plotter and, at the present time, is concerned with the production of the CP1 and EMPD instruments which owe a great deal to his design and innovatory skills. This paper summarises his experiences and views of the production of photogrammetric equipment in England.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméPendant 30 ans l'auteur a participéà l'élaboration d'appareillages pour la photogrammétrie: en particulier les restituteurs Thompson–Watts; et maintenant les appareils CP1 et EMPD qui lui doivent beaucoup. Il condense ici l'expérience et les idées qu'il a dans ce domaine.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungDer Autor ist seit fast 30 Jahren an der Herstellung photogrammetrischer Auswertegeräte beteiligt. Insbesondere verbunden war er mit dem Thompson–Watts Plotter und befasst sich gegenwärtig mit der Fertigung der Geräte CP1 und EMPD, an denen er durch seine schöpferischen Fähigkeiten grossen Anteil hat. In dem Artikel werden seine Erfahrungen und Ansichten bei der Produktion photogrammetrischer Geräte in England zusammengefasst.

Notes: The author is one of the members of the International Committee for Architectural Photogrammetry (CIPA) which met in London during European Architectural Heritage Year. He describes architectural applications of photogrammetry in Poland.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméL'auteur est membre du Comité International de Photogrammétrie Architecturale (C/PA) réuni à Londres à l'occasion de l'Année du Patrimoine Architectural Européen. Il donne des exemples d'applications de la photogrammétrie à l'architecture en Pologne.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungDer Autor ist eines der Mitglieder des Internationalen Komitees für Architekturphotogrammetrie (CIPA), das während des Europäischen Jahres für Denkmalpflege in London tagte. Er beschreibt Anwendungen der Photogrammetrie in der Architektur in Polen.

Notes: Books reviewed:S. Openshaw and R. J. Abrahart, GeocomputationM. Craglia and H. Onsrud, Geographic Information Research: Transatlantic PerspectivesP. J. Halls, Spatial Information and the EnvironmentJ. Sievers and T. Schneider, Second International Symposium on Geographical Names: Geonames 2000J. C. Leachtenauer and R. G. Driggers, Surveillance and Reconnaissance Imaging Systems: Modelling and Performance PredictionP. A. Longley, M. F. Goodchild, D. J. Maguire and D. W. Rhind, Geographic Information Systems and ScienceY. Q. Chen and Y. C. Lee, Geographical Data AcquisitionK. Borre, Plane Networks and their Applications.A. Hirschfield and K. Bowers, Mapping and Analysing Crime Data: Lessons from Research and PracticeO. Koelbl, Proceedings of the Oeepe Workshop on Automation in Digital Photogrammetric ProductionRICS Books, Vertical Aerial Photography and Derived Digital Imagery: Client Specification GuidelinesD. E. Reeve and J. R. Petch, Gis Organisations and People: A Socio-Technical Approach

Notes: Le microscope électronique à balayage donne l'image de la surface d'un objet situé dans une boîte à spécimen où a été fait le vide. Un fin pinceau d'électrons balaie la surface synchroniquement avec un tube cathodique dont l'intensité est modulée en fonction du signal secondaire émanant du spécimen. Le système présente une grande profondeur de champ; on peut donc obtenir différentes perspectives du spécimen en le photographiant sous diverses inclinaisons (perspectives qui sont centrales, mais cependant justiciables d'être traitées comme parallèles pour de forts grandissements) et donc le restituer spatialement. On donne dans la première partie les limitations pratiques de l'appareillage, ainsi que le type et les causes de distorsion de l'image. Dans la deuxième partie, on décrit les caractéristiques d'un appareil de restitution adaptéà un cas standard: grandissement des deux clichés d'un stéréogramme: fixe-angle d'ouverture du faisceau perspectif négligeable (c'est le cas pour de forte grossissements) et convergence relative des deux positions de la plaque porte-spécimen est fixe.〈section xml:id="abs1-2"〉〈title type="main"〉Zusammenfassung Das Abtast-Elektronen-Mikroskop liefert Bilder der Oberfläche von Objekten, die sich in einer Vakuum-Kammer befinden. Ein feiner Elektronenstrahl tastet die Oberfläche in Synchronisation mit einer Kathodenstrahlröhre ab, deren Lichtpunkthelligkeit von dem sekundären Elektronensignal, das von der Probe ausgeht, moduliert wird. Das System gestattet eine grosse Schärfentiefe und erlaubt dadurch verschiedene Projektionen des zu photo-graphierenden Musters durch Neigung desselben zwischen aufeinanderfolgenden Aufnahmen. Aus der Kenntnis der Geometrie der Projektion (die eine Zentralprojektion ist, jedoch für sehr stark vergrösserte Bilder annähernd als Parallel- oder Orthogonalfall behandelt werden kann) ist es daher möglich, zu dreidimensionalen Analysen durch Messung von Parallaxen zu kommen. Teil I der Arbeit handelt von den praktischen Problemen, die sowohl aus den Grenzen für die mechanische Konstruktion von Muster-Halterungen und Auswertegeräten als auch den Verzerrungen der Bilder resultieren. Teil II beschäftigt sich mit praktischen Gesichtspunkten der bewährten Auswerteinstrumente, die speziell für die Lösung eines standard-isierten Problems der Elektronenmikroskopie konstruiert wurden. Bei diesen wird die Vergrösserung der beiden Halbbilder eines Stereobildpaars konstant gehalten, der Divergenzwinkel der peripheren “Strahlen”, die sich aus dem zentralen “Strahl” ergeben, wird als vernachlässigbar angesehen (was bei Bildern mit starker Vergrösserung der Fall ist) und die Neigungswinkeldifferenz zwischen den zwei Lagen der Probe ist konstant.

Notes: The article describes an experiment in which a production block of aerial triangulation, observed by the method of independent models, was repeatedly computed using differing amounts and configurations of control. The block was recomputed to investigate the effects of control errors, of dispensing with the tie strips and of applying different weights to control and tie points. The connexion between the quality of the join of individual models and that of the adjusted block was also investigated.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn décrit une série d'essais effectués sur un bloc de production de triangulation aérienne analytique traité par la méthode des modèles indépendants, destinés àétudier l'influence du nombre et de la configuration des points du canevas d'appui, l'effet d'erreurs sur les points d'appui, l'effet des bandes transversales, et du choix des poids pour les points d'appui et de liaison. On a aussi examiné la corrélation entre la qualityé de l'enchaînement des modèles individuels et celle du bloc compensé.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungBeschreibung eines Versuchs, bei dem ein Aerotriangulationsblock aus der Produktion, der nach der Methode der unabhängigen Bildpaare beobachtet worden war, wiederholt bei verschiedenen Anzahlen und Anordnungen von Passpunkten berechnet wurde. Die Berechnungen erfolgten zur Abschätzung der Einflüsse von Passpunktfehlern. Weiter wurde der Anschluss zu Nachbarstreifen und die Anwendung verschiedener Gewichte für Pass- und Verbindungspunkte untersucht. Desgleichen wurde der Zusammenhang zwischen der Qualität des Zusammenschlusses einzelner Modelle und der des ausgeglichenen Blockes untersucht.

Notes: A plot of relative parallax measurements in a student exercise is proposed for revealing errors in parallax bar readings taken from a stereo-pair of aerial photographs. The sensitivity of the computed heights to measurement error is also evaluated.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn propose un tracé graphique des mesures de parallaxe pour mettre en évidence des erreurs de lecture à la barre de parallaxe.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungEs wird eine Auswertung relativer Parallaxenmessungen bei einer studentischen Übung vorgeschlagen, um Fehler der an einem Stereomikrometer vorgenommenen Ablesungen aufzudecken, die an Hand eines Luftbildpaars erfolgten. Der Einfluss des Messfehiers auf den Höhenfehler wird ebenfalls abgeschätzt.

Notes: Earth observation satellites with 1m resolution, such as Space Imaging's Ikonos system, offer the photogrammetric and remote sensing communities a significant new means for geospatial information collection. These satellites possess the potential for pixel-level geopositioning precision and promise timely, highly automated generation of two dimensional (2D) and three dimensional (3D) spatial information products. This paper concentrates on the pursuit of optimal accuracy and considers an essential first step in the evaluation of the Ikonos imaging system, namely the metric integrity of the sensor system. In the absence of sensor calibration information (the camera model), an empirical evaluation approach has been adopted. This involves an assessment of 2D transformations between image and planar object space. It is shown that based on results obtained in the Melbourne Ikonos Testfield, 2D geopositioning to 0.5 m accuracy is possible from the base-level “Geo”product when a modest amount of good quality ground control is available and sub-pixel image mensuration is achieved. These findings are applicable to both near-nadir imagery and oblique stereo images. Moreover, the results obtained suggest that there are no significant geometric perturbations in the sensor system and initial image processing, which augurs well for the successful application of non-collinearity based 3D orientation and triangulation models for Ikonos imagery.

Notes: Many photogrammetric and GIS applications, such as city modelling, change detection and object recognition, deal with surfaces. Change detection involves looking for differences between two surface models that are obtained from different sensors, for example an optical sensor and a laser scanner, or by the same sensor at different epochs. Surfaces obtained through a sampling process may also have to be compared for future processing (for example transformation parameter estimation and change detection). Surface matching is therefore an essential task in these applications. The matching of surfaces involves two steps. The first step deals with finding the correspondences between two surface points and/or patches. The second step requires the determination of transformation parameters between the two surfaces. However, since most surfaces consist of randomly distributed discrete points and may have different reference systems, finding the correspondences cannot be achieved without knowing the transformation parameters between the two surfaces. Conversely, deriving the transformation parameters requires the knowledge of the correspondence between the two point sets. The suggested approach for surface matching deals with randomly distributed data sets without the need for error prone interpolation and requires no point-to-point correspondence between the two surfaces under consideration. This research simultaneously solves for the correspondence and the transformation parameters using a Modified Iterated Hough Transform for robust parameter estimation. Several experiments are conducted to prove the feasibility and the robustness of the suggested approach, even when a high percentage of change exists.

Notes: It is well recognised that data volume represents a huge overhead for softcopy photogrammetry. For example, a file size of 100 Mbytes will be generated from a black and white aerial photograph if digitised with a resolution of 20μm. Large data volumes not only create storage problems but also affect the speed of image processing. As a consequence, data compression of image data is a matter of great significance. This paper describes an investigation into the effects of image compression on the accuracy of digital terrain models (DTMs) extracted from the compressed images. The JPEG system implemented in the Z/I Imaging ImageStation digital photogrammetric workstation (DPW) was used in the study. A systematic test has been carried out on the effect of different levels of JPEG compression (with Q-factors from 1 to 100) on the resulting DTM, which is automatically generated by the DPW using Match-T software. An analysis of the results from the two sites tested shows that image compression tends to cause more significant degradation when the image texture is richer, but that recommendations on Q-factors for use with the ImageStation appear to err on the side of caution. This analysis leads to some tentative conclusions and recommendations both for future investigation and for photogrammetric practice.

Notes: This paper describes an approach to single image automatic orientation and point determination by using current ortho-images and a DTM, and the experience gained in its implementation. The procedure proposed automatically extracts and matches feature points in evenly distributed patches on aerial images and ortho-images. A large number of image measurements (up to several thousand) are obtained in this process and are included in a robust space resection to determine the orientation parameters of the aerial image. For point determination with a single image, a method is formalised which integrates the DTM interpolation into the space resection so that the 3D ground coordinates of the image points can be determined in a unified mathematical model. Tests and analyses of this method show that the large number of automatic image measurements relieves the requirement for complicated and precise feature extraction and matching methods. The ground points obtained from single image intersection have an accuracy of approximately 1 pixel in planimetry, which fulfils the requirement for ortho-image updating. The elevation accuracy is mainly dependent on the quality of the current DTM and the interpolation method applied to it.

Notes: The paper describes several problems in bubble chamber optics which have counterparts in photogrammetry.〈section xml:id="abs1-2"〉〈title type="main"〉RésuméOn décrit quelques problèmes relatifs à l'optique de la chambre à bulle, qui font écho à des problèmes analogues de photogrammétrie.〈section xml:id="abs1-3"〉〈title type="main"〉ZusammenfassungIm Artikel werden einige Probleme der Optik von Blasenkammern beschrieben, die ihre Gegenstücke in der Photogrammetrie haben.

Notes: The Photogrammetric Society s'honore d'avoir reçu la Visite en mars 1974 du directeur du congrès de la SIP. L'exposé du professeur Halonen a traité de plusieurs aspects de l'actuelle recherche finlandaise en photogrammétrie. A noter le rapport contenant les contributions de deux de ses collègues, J. Hakkarainen et H. Salmenperä sur les problèmes de distorsion et de compensation de blocs.〈section xml:id="abs1-2"〉〈title type="main"〉Zusammenfassung Im Mërz 1974 hatte die Photogrammetric Society die Ehre, den Kongressdirektor der IGP zu empfangen. In einem Vortrag befasste sich Prof. Halonen mit Problemen der gegenwärtig in Finnland durchgeführten photogrammetrischen Forschungsarbeiten. Der folgende Bericht enthält Beiträge seiner zwei Kollegen, J. Hakkarainen und H. Salmenperä, über besondere Probleme der Objektivverzeichnung und Blockausgleichung.

Notes: The Photogrammetric Society was honoured to be addressed by the Congress Director of the International Society for Photogrammetry during March 1974. Professor Halonen's lecture covered several aspects of current photogrammetric research in Finland. The following account contains contributions by two of his colleagues, J. Hakkarainen and H. Salmenperä, on specific aspects of lens distortion and block adjustment.

Notes: A method for computing a spatial intersection of an arbitrary number of rays is demonstrated. The method assumes that the intersection is performed after the photographs have been oriented. It can be used to advantage in various problems, especially when dealing with the determination of coordinates of a point from more than two photographs. The co-ordinates are computed from an adjustment procedure and they refer to a point whose weighted distances from the respective rays are minimised, thus basing the whole solution on a sound geometrical principle. In addition, the method permits the derivation of accuracy estimates for the solved values.

Notes: A critical problem in hydraulics research is accurate measurement of fluvially worked sediments, both in the field and in scaled representations of field situations in laboratory flumes. Such measurement must provide information on individual grain characteristics, and their organisation into structures referred to as bedforms. Existing measurement approaches are based upon mechanical or laser profiling devices, which are both expensive and take considerable time to acquire data, particularly where information is required at very high densities. This paper demonstrates how conventional automated terrain model extraction software, combined with image acquisition using a Kodak DCS460 digital camera, has been effective in generating digital elevation models of complex bed morphology. This has reduced time spent collecting data in the flume and has allowed data collection at much higher spatial and temporal densities. Application of the method is illustrated by research carried out at Hydraulics Research Wallingford. Issues discussed include configuration of photographs and control coordinates; appropriate camera calibration methods; stability of inner orientation of the Kodak DCS460; and accuracies obtained. Comparisons with independent check data reveal that accuracies of ±2.5mm have been achieved using a camera-to-object distance of 4.2 m.

Notes: Motion capture systems based on photogrammetric principles have gained wider use over recent years for applications ranging from clinical gait analysis to the creation of character animation for video games and the motion picture industry. Fast and robust determination of target trajectories is of crucial importance to the provision of optimal performance in the recovery of motion analysis parameters via multi-camera, real-time videometric systems. In this paper, the target path generation sequence is discussed, followed by an account of the formulation of a kinematic model based on the alpha-beta-gamma filter/predictor. A brief description of the photogrammetric feature correspondence determination follows, together with an account of the 2D and 3D marker tracking procedures that were adopted. Finally, initial experimental test results are summarised. These results indicate that the methods developed can provide robust performance and an operational speed which is fast enough to allow real-time 3D target tracking at standard video frame rates and beyond.

Notes: For the conservation of historic monuments, there may be considerable value in automating the methods of detection and analysis of surface condition and deterioration. This paper describes tests using a range of multiband and multispectral images for the assessment of architectural façade cover by means of supervised image classifications. From the spectral training sets, both pairwise distances (the Euclidean distance and the Jeffries-Matusita (J-M) distance) are calculated and are used to predict the a posteriori accuracy of image classification. Furthermore, the effects of increasing the number of spectral bands (blue, green, red and near-infrared) in the supervised maximum-likelihood classification procedures are also analysed, as are the benefits of applying principal components. The resultant multiband datasets increased both the J-M distance and the classification accuracy of the architectural façade, and thus enabled better identification and recognition of the different kinds of façade-cover features.

Notes: The author describes the photogrammetric equipment in use by the Royal Commission on Historical Monuments (England), the methods used and the work that is being done in architectural recording. The difficulties and the possibilities of future architectural work in the United Kingdom are discussed and the achievements of some other countries in this field are reviewed.

Notes: Several problems are encountered when collecting traffic information by conventional methods and which leave scope for the development of more comprehensive techniques. This paper reviews the potential of different types of photography as an effective means of obtaining comprehensive traffic information. Comparisons between conventional methods and photographic methods are made. The different types of available photography are discussed, together with their uses in the field of traffic data acquisition. Finally, the paper assesses the use of automatic and semiautomatic methods of photographic data analysis in this context.

Notes: Book reviews in this article:PHOTOGRAMMETRIC GUIDE. By J. Albertz and W. Kreiling.THE READJUSTMENT OF THE RETRIANGULATION OF GREAT BRITAIN, AND ITS RELATIONSHIP TO THE EUROPEAN TERRESTRIAL AND SATELLITE NETWORKS. By V. Ashkenazi, P. A. Cross, M. J. K. Davies and D. W. Proctor.GUIDE TO SITE SURVEYING. Edited by R. Hewitt.PHOTOGRAMMÉTRIE GÉNÉRALE. By H. Bonneval.

Notes: The Ordnance Survey makes extensive use of air survey in its mapping programmes at scales of 1 : 1250, 1 : 2500 and 1 : 10 000. A short history of the development of air survey within the Ordnance Survey leads into a description of current methods including the flying, processing and aerial triangulation tasks as well as the plotting of the maps by instrumental or graphical means.

Notes: The paper describes a method for the automatic determination of height profiles in the stereomodel. The model is scanned automatically in epipolar planes. The photographic densities are recorded. The density values are correlated, either on or off line, to obtain the height profiles. The method was developed for the analytical plotter but can be applied to other photogrammetric instruments.

Notes: The author reminisces upon a career of almost 40 years as a practising surveyor photogrammetrist, both as a Royal Engineer officer and as a director of a commercial survey organisation. The reminiscences include service with the Survey of India, war time operations in the Middle East and South East Asia Command, and commercial surveys of all types in developing countries. Professional service with international surveying and photogrammetric organisations is also mentioned, with particular reference to the fraternal aspects of international photogrammetry.

Notes: Methods and results of practical applications of block adjustment by independent model cadastral surveys are described. The wider implications of the results are assessed in conjunction with current research trends in the adjustment of extremely large blocks for small scale mapping and in the use of the bundle adjustment method.

Notes: 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.

Notes: A study of coastal marshland using panchromatic vertical aerial photography suggested that October was the best season of the year for the interpretation of vegetation while February was most suitable for examining topographical or pedological features. False colour film was used to isolate certain plants from bare mudflats where it was impossible to identify these by differences in texture or height.

Notes: The paper considers the experimental comparison of a method of aerial triangulation in previous experimental use by Eden and the standard Ordnance Survey method using stereocomparators. The accuracy of plan fixations was high by both methods, with Eden's method providing the better result. A comparison is made of the times taken under experimental conditions for both methods.

Notes: The paper discusses aspects of air photography and electronic processes which produce imagery by infra-red radiation and by radar waves. After preliminary comments on lenses, laboratory techniques and colour photography, the author indicates certain advantages in simultaneous photography using black and white, infra-red and colour films. Moreover, information is given on simultaneous photography by satellite and the paper terminates with a resume of methods that are used to obtain imagery by infra-red radiation and by radar.

Notes: Automatic surface reconstruction by means of digital image matching essentially involves computation in both image and object spaces. In image space, image matching is performed according to certain radiometric and geometric similarity criteria for conjugate point determination. The matching operations may therefore be regarded as decision–making processes. In practice, however, the similarity criteria for conjugate point determination demonstrate non–deterministic behaviour. Thus, the nature of these decision–making processes is more compatible with fuzzy reasoning concepts. In object space, on the other hand, surface reconstruction procedures, which operate on the basis of previously determined conjugate points, are essentially deterministic in nature and hence demand rigorous geometric modelling. In this paper, a new approach for automatic surface modelling is proposed, based on two different mathematical treatments: a fuzzy logic reasoning method for the conjugate point determination in image space; and a robust finite elements approach for the surface modelling in object space. Tests carried out on real data demonstrate the high potential of the strategy proposed.

Notes: The paper describes how a computer can be programmed to form triangles from points, having x, y and z co-ordinates and selected in an arbitrary manner, to calculate the area of each triangle and to determine the volume of the prism above or below the triangle. The sum of these volumes gives the total volume of a body.

Notes: The author traces the development of the use of photogrammetry in the Swiss cadastre, showing how the methods had to be adapted to meet the regulations designed for ground surveys. He shows how ground and photogrammetric measurements are adjusted together to enable the high accuracy requirements to be met.

Notes: The paper describes an experiment using three different methods for the production of control for topographic mapping from super-wide angle photography. The result showed that aerial triangulation by independent models observed on a Wild A9 would show economic advantages in cartographic effort required, control requirements, and accuracy attained in contouring. The experiment also indicated that great benefit in heighting accuracy is derived from the addition of tie strips flown at right angles to the main photographic cover at a suitable interval and that heights supplied by airborne profile recorder are not sufficiently accurate to be economically advantageous where close interval contours are a requirement.