TOGRAPHS
), Close Range,
tally destroyed, is
/ consist the most
> of such pictures
the building/object
is presented. The
, gave a 3D digital
; a CAD package.
egree of accuracy
ical Archive of the
llections, special
s of the area of
) resulted to the
es, most of them
Jllding, taken from
ales and on dates
ntury until the date
| important of them
roduced, so that
ide
of the area during
30's. Only one pair
proved useful for
taken in 1965, at a
of the building, in
of the building at a
vestern side of the
d in 1921
“a scale of 1:50,
at a scale of 1:50,
r changing the use
Nautical Museam
the first floor at a
of the second floor
ing old plans of the
compared with the
rtant of them are
e upper part of the
e facade plans
1996
e the windows which are shown on the upper part of the
western side and in fact never constructed
e the structure of the tile ceilings instead of cement-made
ones on the eastern and western side of the building
e the structure of a ventilator on the ceiling of the tower-
clock, which is not shown in any one of the facades
e certain details on the sides of the tower-clock
e certain differences on the windows.
Besides, no other plan of the northern side of the building
was found.
3. PHOTOGRAMMETRIC DATA PROCESSING
The determination of the necessary digital data (3D
coordinates of characteristic points) for the completion and
the correction of the existing plans of the facades is
accomplished. The procedure followed consists of
e analytical processing of the stereopair of airphotos and
e digital rectification of various planes of the facades on
the amateur pictures.
3.1 Analytical Processing of the airphotos
The X, Y, Z coordinates of the main characteristic points
of the building, which were recognisable on the stereopair
of airphotos of 1965, such as the corners of the building in
various hights, on the balconies, ceilings, clock etc, were
determined. The coordinate calculation was made on an
analytical photogrammetric instrument. For the orientation
of the stereopair the coordinates of 5 control points were
measured by field surveying methods with an accuracy of
a few centimeters. These control points are clearly
Figure 1. Old amateur photograph of the northeastern side of the building
^ +
defined, easily recognisable on the airphotos, located on
the surrounding area of the building and belong to
permanent structures that have remained unchanged since
1965. The characteristic points of the building that have
been determined by stereorestitution are 120 in total and
their coordinates have been calculated with an accuracy of
15-25 um on the photo scale, or of 10-15 cm on the
ground.
3.2 Digital Rectifications
Digital Rectifications of all planes of each of the four sides
of the building have been accomplished by using the
calculated coordinates of the characteristic points and
metric information derived from the existing plans. The
hardware used was a standard IBM-compatible PC with
80486 microprocessor and 8 Mb of RAM.
For this purpose, the seven forementioned most important
amateur photos were scanned with a 600 dpi resolution.
Since each side of the building consists of more than five
planes (see Fig. 2 & 6), occasionally certain sides had to
be produced by a combination of rectified planes taken
from more than one pictures, in order to avoid hidden parts
or large tilts or parts of small scale. The scales of the
scanned photos are between 1:100 and 1:300. Since a
magnified papercopy was used the image quality of the
analog photos was comparatively poor, so a careful
radiometric image processing of the scanned images
(contrast and brightness enhancement, edge detection etc)
was made.
In most rectification planes the determination of control
points was impossible, because there was a difficulty in
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996