h the aid of 
tained very 
| particular, 
ications, for 
speed and 
rather easy 
otogramme- 
ay — a very 
1mend some 
1gress about 
ular, X-ray 
is of the 
| connection 
: have to be 
can find the 
arly in con- 
Parkinson's 
deep in the 
e aid of two 
through the 
rrect spot to 
e hands im- 
sting to see. 
add one or 
Which have 
'st, I would 
within these 
ite distance. 
r calibration 
of fixing the 
found that 
; required it 
nera against 
otted results 
pass points 
'eliable cali- 
of medium 
been over- 
:t that some 
tained from 
pplication is 
of accuracy. 
iachines of a 
jeras which 
large distor- 
pe of distor- 
er this after- 
ance to the 
of the siting 
le variety of 
ipework in- 
Those pipes 
ind a photo- 
  
  
N 
| 
Ë 
| 
DISCUSSION 73 
grammetric interpretation of what exists gives 
the industry an idea of the size of pipe required 
to replace them, how the pipe should be bent 
to fit the apparatus and other information of 
that nature. Here a plotted accuracy at 1 : 1 
scale need be no better than a quarter of an 
inch. 
I was interested in Professor Burkhardt's 
camera using extension rings. We have a similar 
camera in use on a lathe bed and we have inter- 
changeable rings for various lenses of various 
focal lengths; with our combination we can get 
from 10 inches to 4 feet within our focussing 
range, but we do change the lenses as well. 
Another interesting application of this work 
which I have been given recently is in high 
temperature work. It has come to my notice that 
a certain errosion in the whorls of refractory 
furnaces takes place, and the rate of errosion 
seems to be dependent upon the position in the 
furnace chimney. The temperatures are up to 
800? C to 1000* C and, therefore, the only way 
we have determined of measuring this errosion 
is by photogrammetric methods. 
The same instantaneous record is required, 
for instance, to investigate the pools which exist 
during welding. There is always a pool or a 
little well formed during the welding process 
which disappears on solidification, and the only 
information one can get as far as I can see on 
that is to have an instantaneous pair of photo- 
graphs at the time the weld is molten. 
Prof H. L. CAMERON: There is one other 
application of photogrammetry which I would 
like to mention. Listening this afternoon I am 
afraid some of us are a bit in danger of getting 
lost among the microns. There is a great deal of, 
you might say, cut and try engineering which 
has to do with measuring things to a very rough 
degree of accuracy, but if a method can be 
devised to do this it is sufficient for the job. I 
have in mind a problem we had in Canada last 
year, where we had to evaluate the accuracy of 
the Decca navigator by taking a single photo- 
graph of a strict point on the ground and simul- 
taneously photographing the Decca meter in the 
aircraft. The idea being originally that the centre 
of the photograph would be the plumb point be- 
neath the aircraft and a simple measurement 
would give them the closeness to the point at 
Which they were aiming. Unfortunately, the pho- 
tographs were not vertical and it was necessary 
to devise a means to get a plumb point by one 
photograph. After some thought the following 
method was devised. 
Vertical objects — and we have all seen 
Archives 6 
photo images of vertical objects — in vertical 
photographs give you a foreshortened version 
of the object itself, for example, a large smoke- 
stack. If this vertical object image is projected 
it will be the projection of a plane containing a 
series of vertical lines along the plane in the 
photo and on the ground. If you take two ver- 
tical objects not in the same straight line the 
intersection of the two projections will give you 
the plumb point. This was tried out and I am 
happy to report it worked very well; they were 
able to locate the plumb point relative to the 
ground point and they evaluated the Decca. I 
am not an agent for the Decca company but I 
will say that the Decca is extremely accurate. 
This sort of, you might say, feet and inches 
photogrammetry should not be forgotten in the 
consideration of extreme accuracy which we 
have been talking about throughout many of 
these discussions. On the other hand, I am not 
looking down the proverbial nose at the extreme 
accuracy, but I think the other end of the scale 
should be considered: one end where you are 
doing it in feet and yards and the other end 
where you are doing it in microns. I think there 
is something to be said for the gunners at the 
battle of Trafalgar, who were instructed to take 
about a shovelful of powder and put it in their 
guns. 
Herr Prof BURKHARDT: Meine Herren Kol- 
legen. Ich danke für die Ausführungen. Sind 
noch weiter Wortmeldungen, Ich glaube, wir 
müssen allmählich zum Schluss kommen, und 
ich darf noch sagen, dass wir die kürzlichen Be- 
richte in folgender Weise für die Resolution zu- 
sammenfassen können. 
A. Die Röntgenmedizin. Sind Sie einverstan- 
den, dass also als künftiger Schwerpunkt für die 
Weiterarbeit der Kommission V zu empfehlen 
ist — Röntgenmedizin. 
B. Nahphotogrammetrie, insbesondere die An- 
wendung in der Archaelogie und Architektur- 
aufnahme. Also dann haben wir auch gleich die 
verschiedenen anderen Berichte miterfasst, wie 
zB von Herrn Kowalczyk und von Herrn More- 
land. Die Probleme sind ja ähnlich. Und dann 
wäre C. noch die Ozeanographie, worin Herr 
Cameron ja die Absicht hat, einmal die Strö- 
mungen des Golfstroms zu bestimmen. Also 
wenn man diese drei Arbeiten, die sich wohl am 
meisten abzeichnen in dieser Arbeit für die 
Weiterarbeit empfiehlt, dann werden wir der 
Kommission V, glaube ich, nur nützlich sein. 
Und dann wurde von Herrn Hallert vorgeschla- 
gen, als vierten Punkt noch aufzunehmen, dass 
die Kommission allen Kollegen, die in diesem