/ith
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rite
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oun
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ject
tial
on
- computing measured coordinates of
zones from digitizer coordinate system
to coordinate system of photographs;
- computing of coordinates of
zones'centres relatively the principal point
of photographs ;
- computing and transfer of homologe-
ous points coordinates from common
photo to next photos for forward and
lateral overlaps.
When the work with a digitizer is finished,
the following files in chosen directory are
open: HEADLINE (*.prJ) and NUMBERS
OF COORDINATES (beg.*), containing
numbers of photos , quantity and numbers
of points and their coordinates. When
project designing is finished these files are
removed to the directory, where works on
STEREOANAGRAPH analytical plotter will
be carried out.
2.2. Measuring of stereopair
coordinates
This process is the main one in the new
technology. Differently from the
technology, used at enterprices it allows
to realize a digital transfer of tie points and
exclude both the process of artificial
marking and essential expensive
equipment: point marking instrument PUG
(Swiss), Transmark and Interpretaskop
(Germany), NT and DSI (Russia).
A STEREOANAGRAPH analytical plotter
permits to get higher instrumental
precision of measurings till 3 mkm and an
automated process for driver of floating
marks to zones of stereoviewing
(observed) points, process of coordinates
point transfer, processes of recording and
numbering of points, checking of errors on
all steps of photo measurment .
The core of new technology is a procedure
of measuring of separate stereopair. To
avoid frequent repetition of this procedure
439
data for adjustment of strip network were
formed. In turn photogrammetric block
includes totality of the strips. There is a
special feature for tie points of lateral
overlap in the new technology. The points
of lateral overlap (that at the same time are
tie points in forward overlap) finally were
calculated during process of mesuring of a
previous strip. To begin the next strip it is
necessery to transfer tie points from
stereopair of previous strip.
Interior orientation of stereopair
(diapositives) is carried out for reformation
of coordinate system during digital point
transfer and computing of coordinates of
the principal point of photos. The
procedure is carried out semiautomaticly.
Carriages of the analytical plotter are
reached automaticly to zones of all fiducial
marks.
First, an operator- revolving manual
Steering-wheel combines the floating mark
with a fiducial mark on the left photo, than
on the right one . After that he records
measuring coordinates as it was said
above. Process of fiducial marks mesuring
is rather important because all processes
suches like digital point transfer and block
adjustment's accuracy for spare networks
depend on accuracy of their measuring.
Choice and measuring of point coordinates
are carried out under control of data file of
project designing. Software controls
succesively approaches floating marks to
centres of zones on the left and riglt
photos, marked on contact paper photos
during the project designing. Viewing the
centres of zone, an operator selects
points for bridging.
Maybe an operator with some causes will
not choose the same point, that was
selected in the project and it will situate
out of marked zone. It is only possible if
there is an additional checking of its
image on neighbouring photos on zones
of forward and lateral overlaps. Order of
measuring of a stereo pair point on the
left and right photos with stereo veiwing is
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996