SPACE-TIME PHOTOGRAMMETRIC DETERMINATIONS
FOR OPTIMIZING THE RIVER NAVIGATION
Ovidiu Andrei
and
Eugen Cotovanu
Romanian Committee of Photogrammetry
ABSTRACT
The photogrammetrical space - time
measurements, with synchronized taking of
photograms, spread on large spaces, find
themselves a direct application in the
technical field, namely in the optimizing
study of the river navigation. It refers
to the photogrammetrical measurements con-
cerning a naval convoy in moving state,
while inscribing in a curve of the Danube
navigation channel, at the hydroelectrical
complex of the Iron Gates With the pur-
pose of making at the same time a study of
the achieved precision in such space - time
measurements, simultaneous telemetrical
measurements were made. They were synchro-
nized with the taking of photograms, so
that finally a comparison of the results
achieved by two methods, be possible.
The photogrammetry, as a discipline
dealing with a phenomenon or object ren-
dering and sizing, on the basis of photo-
grams, in order to determine their shape
and position in space, and time, has been
concentrated mainly on the space measuring
of objects.
Either in the case of air photogram-
metry or the ground one, having in view
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both the design activity and the laborato-
ry researches, the object which is to be
measured has often a fixed position against
a, three-dimensional reference system, or
its movement is so slowly that it may be
considered motionless taking into account
the time of taking photograms. o
This characteristic of the photo-
grammetry was considered as & limit be-
cause it excluded the phenomena with ra-
pid movement out of the field of photo-
grammetric measurements.
To extend the photogrammetric mea-
surements in the space-time range is an
important problem and it complies with
the ever growing technical necessity of
an accurate measuring of the moving phe-
nomena as far as the respective movement
is faster and more complicated.
We can give exemples such as the
problem of wave behaviour necessary to
the ship design and the location of har-
bours or sea platforms for oil extractiors
or the problem of controlling the ship
launchings from the docks, or to study on
models the way of the moving boat etc.
In most cases the measurements of
phenomena in motion i8 limited to the use
of some mechanical,eleetromagnetical or
electronic devices placed in different
points in order to record the phenomenon
development in these points.
No matter how much fine and rigorous
such an operation would be, the final re-
sults is a measurement of isolated points
which only by interpolation could give the
phenomenon interpretation on the whole of
his movement.
An interpolation implies an approxi-
mation which is the less accurate the smal-
ler the number of points used at interpo-
lation is.
Using the photogrammetry in the
space - time range eliminates this short-
coming. The advantages of this system con-
sists of & general recording which enables
us to obtain very important information.
From stereophotogrammetric point of
view the problem of a space-time measure-
ment has two different aspects.
One of them refers to the determination
of the moving object shape and position at
