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