SIMPLE PHOTOGRAMMETRIC METHODS WITH ARPENTEUR
3-D PLOTTING AND ORTHOIMAGE GENERATION: THE I MAGE PROCESS
Pierre Drap*, Pierre Grussenmeyer **, Gilles Gaillard***
* MAP-GAMSAU unir CNRS 694, Ecole d’Architecture, Marseille, France
Pierre.Drap@gamsau.archi.fr
** ENSA1S-LERGEC, Photogrammetry and Geomatics Group, Strasbourg, France
Pierre.Grussenmeyer@ensais.u-strasbg.fr
***STRATOS Documentation
GillesGaillard@compuserve.com
KEYWORDS: Architectural Photogrammetry, Archaeology, Digital Images, Java, Orthoimage
ABSTRACT
This paper focuses on an original approach to architectural survey whereby the measuring step, driven by an architectural model, is
left to the architect’s or the archaeologist’s initiative, with reduced participation by the photogrammetric expert. A new set of tools
to this end is available in the Web-based tool ARPENTEUR (Architectural PhotogrammEtry Network Tool for Education and
Research).
Surveys are accomplished with the so-called I-MAGE process (Image processing and Measure Assisted by Geometrical primitive)
which enables the user, for instance, to obtain 3-D measurements while digitizing a single image with "no loss" of accuracy. I-
MAGE is a new measuring method for digitizing 3-D points, based on the coupling of image correlation and the expected shape of
objects. Shapes are primitive surfaces or partial surfaces like planes, cylinders, cones and spheres. We have developed the I-MAGE
process to assist the plotting phase: the homologous point is determined by the system using both the image orientation and the
geometrical primitive computed on a set of 3D points already measured.
On the other hand, so far, accuracy has not always been the principal purpose of surveys in archaeology and architecture. Each
photograph contains a tremendous amount of qualitative information which is not often used to its full potential. We suggest,
therefore, the full use of all the information made available during the photogrammetric process, such as: camera orientation results,
3-D primitive surface computation, and rectification or projection of the images onto the primitives. The result is a scaled image
containing all of the qualitative information. Accuracy is then a consequence of the hypothesis made when nearing the real surface
with a primitive. We present as an example an orthoimage generation from a rubbed vault (estimated with a cylindrical primitive) at
the frigidarium in the Thermes de Cluny, at the Museum of the Middle-Ages, Paris.
1. ARPENTEUR PROJECT DESCRIPTION
ARPENTEUR is a digital photogrammetry software package running on the Web jointly developed by MAP-
gamsau (a laboratory of the French National Science Council) at the School of Architecture at MARSEILLES and
the Photogrammetry and Geomatics Group of ENSAIS-STRASBOURG. The package is intended to be used as a
Web-based tool since photogrammetric and modeling concepts are embedded in Web technology and Java IM
programming language. Two kinds of servers are available:
• A HTTP server (Hyper Text Transfer Protocol) is used for the connection to computers equipped with ARPENTEUR. There are
presently two possibilities: one in Strasbourg and one in Marseilles. A user can create a workspace to access his / her own data
or example projects.
• An FTP server is used to upload or download data between the (remote) server and the local computer. Data or result fdes can
be handled by this means.
Several example, configuration, or help files are also available on the ARPENTEUR Web page (http://www.arpenteur.net).
The goals of the project are as follows:
• As software for education and research, the JavaTM programming language includes tools and technology that allows diverse
workgroups of several developers or users, using diverse hardware platforms, to work together free ol software installation
costs;
• Due to the specialization of the two principal partners in Strasbourg and Marseilles, the modeling tools have been developed for
close-range applications, mainly for the description of architectural information;
• ARPENTEUR is, above all, a photogrammetric tool and its aim is to provide not only different orientation solutions for
photogrammetrists, but also simple tools for non-specialists using desktop computers.
Proceedings 18 th International Symposium CIPA 2001
Potsdam (Germany), September 18 - 21, 2001
