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THE DEVELOPMENT OF A DIGITAL PHOTOGRAMMETRIC SOFTCOPY KIT FOR
EDUCATIONAL PURPOSES
L. Coelho?^
* The Military Institute of Engineering, Cartographic Engineering Department, Praca General Tibürcio 80, Rio de
Janeiro/RJ — Brazil — Icoelho Q universiabrasil.net
^ 4^ Surveying Division — Avenida Marechal Bittencourt 97, Compensa, Manaus/AM - Brazil —
Icoelho @universiabrasil.net
Commission VI, WG VI/2
KEY WORDS: Photogrammetry, Developing Countries, Learning, Teaching, Education, Software.
ABSTRACT:
This paper shows the current efforts in order to develop a digital photogrammetric softcopy kit which intends to provide a link
between theory and practice in the field of Photogrammetry. These efforts have started in 2002, with the development of the first
modules of the E-Foto kit: image viewer, project configuration, camera parameters, interior orientation and digital mensuration. The
project was based upon a two-principle approach: freedom of software and self-teaching. This means that all software are delivered
under à free license (in this case, the GNU GPL), which turns it accessible to users who might compile and use it, study its code or
even develop new modules for it. The second principle relies on a considerable amount of teaching material that accompanies the
software, including an on line help. the e-book on Digital Photogrammetry and the project's support homepage. Based on these
resources, the user will be able to study the main photogrammetric principles, how they work and how to use them. Its main
objective is to diminish the gap that exists nowadays between the teaching of Photogrammetry and Remote Sensing in universities
and Research Institutions of developing countries and the high-tech expensive systems that are used under the spatial data production
environment. Currently, there are five modules ready to use, in English and Portuguese, and one under development. Both Linux
and Windows versions are available. Thee-book on Digital Photogrammetry is available only in Portuguese and is distributed as a
series of portable document files (pdf's).
1.INTRODUCTION
1.1 Photogrammetry: a Brief History
Photogrammetry can be regarded as "the science and
technology of obtaining spatial measurements and other
geometrically reliable derived products from photographs"
(Kiefer, Lillesand, 2000). Simply put, it concerns any kind of
reconstruction of the tri-dimensional space through bi-
dimensional images.
Photogrammetry, nowadays, has many uses, such as:
architecture, quality control, 3-D modeling and, of course,
cartography. By the way, during many years, it was considered
the most practical form of obtaining reliable topographie maps.
That's why most mapping agencies still rely on its use for such
purposes.
Its main mathematical principles were established many years
ago, and first implemented through optical and mechanical
instruments. Those were, of course, very expensive, and the
technology concerning their design and construction was
somehow hidden. Science is a stone wall and one cannot build
it all at once — that's why most photogrammetric instruments
were built by the already active optical instruments industries
who had the expertise in implementing complex machinery.
Those who have tried to start building such aviographs from the
scratch did not succeed.
Most solutions were limited only to specific types of cameras
and because of that, they were not very versatile. Everything
had to be specifically designed for that particular
photogrammetric system, otherwise, it could not be used.
Those reasons (and many others) made photogrammetry a very
expensive science. Poor countries had problems in acquiring
those instruments. and in most cases they were at first
destinated to their mapping agencies. University and research
centers most of the time had to deal with second-hand
equipment. This contributed to the lack of knowledge many
professionals presented when having to use the most modern
photogrammetric instruments.
In the early nineties, however, a huge revolution was seen. It
was the first time that computers were powerful enough to
handle efficiently large image files. This turned available the
first completely computer-based photogrammetric systems,
which made, for the first time, Photogrammetry independent
from optical and mechanical implementations. This new field
(Digital Photogrammetry) relied on three basic principles:
computer hardware (advanced enough for near-real time image
processing), photogrammetric software — (mathematical
implementations of the principles long ago discovered) and
knowledge (to implement and use the software). Even at that
time, the sum of all three factors was considerably cheaper than
a single mechanical instrument. Some companies, many of
them still new to that field of science. have invested heavily on
digital implementations for photogrammetric principles, and
lead the market to completely change the way tri-dimentional
photogrammetric data were produced.
Unfortunately, prices remained high and the access to digital
stations continued to be limited only to those who could afford
it. However, the technology was now open to everyone who
had those three principles (hardware, software and trained
personnel) already described.
Based on previous experience, the idea or developing a
photogrammetric softcopy kit at the Military Institute of
Engineering was born. The details concerning its development
will be better described on next topic.
1.2 The E-FOTO Project