Photogrammetrie ausserordentlich typisch ist. 
Ich arbeite in Berlin, wie ich schon einmal aus- 
geführt habe, mit einem Architekten, einem 
Kollegen zusammen, und wir machen Bau- 
aufnahmen, die von Architekturstudenten aus- 
gewertet werden, und es zeigt sich, dass am 
Stereoplanigraphen, den wir in Berlin zur Ver- 
fügung haben, die Genauigkeit gerade eben aus- 
reicht, um die Forderungen in der Genauigkeit 
von Details zu erfüllen. Zum Beispiel die genau- 
en Proportionen von Simskanten und Sims- 
gestaltungen wirklich wiederzugeben. Es kommt 
bei allen diesen Problemen mehr auf die Nach- 
bargenauigkeit, also auf die Detailsgenauigkeit 
an. Und es ist in dem Zusammenhang sehr 
wichtig, dass man das optimale Basisverhältnis 
wählt. Wir haben Basisverhältnisse zwischen 
1 : 4 und 1 : 10 angewandt, wobei einem Basis- 
verhältnis 1 : 10 schon verhàáltnismàássig grosse 
relative Fehler der Rechenergebnisse mit Tiefe 
entsprechen. 
Sind zu diesen Fragen noch Wortmeldungen? 
— Herr Kollege Hallert? 
Mr B. HALLERT: Since there are a few 
moments I would like to say something about 
medical experiments which have been done in 
Sweden, particularly with respect to X-ray 
photogrammetry. One example is: how do we 
chew? How do we move our under-jaw? It 
depends on the construction of the joint, and 
we must take measurements if we want to find 
the truth. In this case a stroboscope was used 
together with an open stereo camera in a dark 
room. The stroboscope was flashing at 6 flashes 
a second and simultaneously an X-ray camera 
took X-ray photographs right through the head. 
It was then possible to determine very accurately 
how the jaw moved. 
Further, there is the problem of what 
happens to the jaw when a tooth is taken out. 
This is a problem that has also been investigated 
with the aid of repeated X-ray photography and 
simple co-ordinate transformations between the 
photographs which have been taken time after 
time. 
Again, what happens within the tenth of a 
second when two cars collide? In other words, 
what happens in an automobile collision? That 
has also been studied with the aid of a strobo- 
scope which flashed 300 flashes a second, 
having a test car with relecting details and an 
open stereocamera close by. The car collided in 
that case with a barrier. There is a publication 
given to this Congress with a report on these 
measurements, which are impossible to make 
reliable in other ways than with photogramme- 
72 DISCUSSION 
try. People tried earlier to do it with the aid of 
auxiliary meters, etc, but only obtained very 
poor results and the accuracy, in particular, 
could not be studied in that way. 
There are also a lot of other applications, for 
instance, determination of current, speed and 
direction of current, etc, which are rather easy 
to perform and doubtless where photogramme- 
try has — and in the future will play — a very 
important role. I would like to recommend some 
of the publications given to this Congress about 
such special applications, in particular, X-ray 
photogrammetry which certainly is of the 
greatest importance, for instance, in connection 
with operations on the brain. Points have to be 
located first and then the surgeon can find the 
correct place. This is used particularly in con- 
nection with the treatment of Parkinson’s 
disease, when there is a point very deep in the 
brain that has to be burned with the aid of two 
electrodes which are put in right through the 
head and which must meet at the correct spot to 
cure the disease; the shaking of the hands im- 
mediately stops and it is very interesting to see, 
Dr E. Miskın: I would like to add one or 
two remarks to many of the subjects which have 
been dealt with this afternoon. First, I would 
like to take the question of accuracy within these 
cameras which have optics at a finite distance. 
Firstly, one has the problem of their calibration 
and, secondly, one has the problem of fixing the 
objects for the calibration. I have found that 
where work of medium accuracy is required it 
is quite sufficient to calibrate the camera against 
the plotting machine, and if the plotted results 
agree with the calibrated results for pass points 
then one can take that as being a reliable cali- 
bration of the camera for a work of medium 
accuracy. 
One point which has, I think, been over- 
looked in our discussions is the fact that some 
plotting and some data which is obtained from 
this close range photogrammetric application is 
not needed to a very high degree of accuracy. 
In that case one could use plotting machines of a 
very simple nature and have cameras which 
have a high resolution but possibly large distor- 
tion characteristics relative to the type of distor- 
tion to which we have referred earlier this after- 
noon. 
I would refer you in this instance to the 
industrial use in the chemical field of the siting 
of pipes. You are well aware of the variety of 
sizes, shapes and bends in the pipework in- 
stallations of chemical factories. Those pipes 
and boilers are frequently replaced and a photo- 
  
  
   
     
   
   
   
   
   
   
   
   
   
   
   
   
   
   
    
  
    
   
   
    
   
   
   
   
   
   
   
  
   
   
   
   
    
  
    
  
   
   
   
   
   
   
    
   
   
   
   
    
    
    
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