..
asin Conditions Initial Decisions Required Tools Possible Measures to
Improve Results
18 environmental ! type of photography photographic e. improvement of taking
conditions — aerial | equipment | equipment
— terrestrial
J | - close-range I | ® control oi inner f
PRE EE TEE - under-water, etc. |l | | orientation of camera
Y ties of object | | |
: | enhancement of object
tion method of data M details, e.g. by
) reduction | | lighting effects
| — from single Photo |
graphs a
object data re- —- from stereo pairs * | additional data to
| M strengthen outer €
quested photogramme- Orientation
y I | tric instrumen-|| :
: tation
) method of svatuation/| | 7 :
; changing environmen-
) T: ep SES i | HH tal conditions, e.g.
t ) v nolviisul ) computer by climatizing
y programs |
accuracy re- |
quirements | general statement ofl|l Specialized camera
L_ approach & methods | set-up, e.g. change
ny Le cs re Lire rel Of gable combination
are accuracy a priori accuracy to Y Of TCU optique
r E. equirements | be expected P graphs
| 11filled ^
2 no—434 reconsideration of chosen Specialisation of
approach & methods investi- © computer programs
- gation of ways to improve d
der yes results Bl
, i combination of photo-
detailed formulation grammetry and other
of working procedure measuring techniques
es
: Table T
Measures to Improve the Results
S For improvement and control of intermittent steps and final results numerous experiments
were made, some of which were incorporated into the working procedure that finally evolved. These
S were :
- The environmental conditions were improved by concreted platforms for the geodetic instruments
for control point determination. The models were photographed at night in order to avoid vibrations,
- Areas of the net which could not be covered by vertical photography were filled in with oblique
photos taken with the VEROPLAST.
- The SINAR camera was recalibrated prior to photography on an optical bench,
a-
t - A special lighting scheme was chosen to enhance object details and certain points were fitted out
'ator.
with auxiliary devices (see also [1]).
- The inner orientation of the taking camera was controlled by recalibrating it from the actual
measuring photographs. The procedure and the computer program used was basically that of
HARLEY [2]. It proved to be advantageous to extend Harley's original version to permit the cal-
culation of the corrections to the observations and the inverse weight matrix for the unknowns,
Also two additional unknowns for linear plate deformation in two directions were incorporated,
These were later dropped again after they proved to be insignificant, In order to have good approxi-
mate coordinates for the projection center, the mid-point of the aperture was marked on the outside
of the objective and the mark was intersected in the course of geodetic control point determination,
35]
