i BE 
  
  
  
PHOTOGRAMMETRIC ENGINEERING 
on to the photomultiplier tubes, where the de- 
tail in each diapositive plate was recorded. 
These dichroic mirrors permit viewing the 
stereoscopic model by the operator in the 
customary complementary colors, red and 
green, since the red and green lights are able 
to pass through the mirrors and project the 
diapositive images on to the platten. When 
placed in any xy position within the model, 
the unit is capable of arriving at the z position 
in most instances. Also, at any position in the 
model the instrument is capable of removing 
the y parallax automatically at any point by 
pushing a button corresponding to the pro- 
jector motion desired. This permits the pro- 
jector to be semi-automatically oriented. 
The Photographic Survey Corporation of 
Canada has completed a business arrange- 
ment with the Benson Lehner Corporation of 
Los Angeles, California, for fabricating this 
equipment called a Stereomat, and placing it 
on the commercial market. 
While these developments were in process, 
another closely related development proved 
successful. In 1953, Mr. Russell Bean pro- 
duced the first working model of his Ortho- 
photoscope, although it had been somewhere 
between his mind and the drawing board for 
the previous 17 years. Combination of this de- 
vice with an automatic contouring or pro- 
filing instrument shows considerable promise 
in automatizing the stereoplotting process. 
With the objective of taking advantage 
quickly of new developments, the Army Map 
Service conceived the Integrated Mapping 
System. The first model of this project is now 
being procured for AMS by USERDL. This 
system is automatic in some phases and man- 
ual in others. 
Indicative of our time in which scientific 
advancement is accelerating at an astounding 
rate. we have had considerable study and in- 
vestigation going on with the objective of 
combining many if not all the steps of map- 
ping into one overall system, even before cer- 
tain steps have been perfected within them- 
selves. There appears to be some merit to this 
since there is always the possibility of a short 
cut or the elimination of some step, without 
wasting time on its development. The system 
developed by Paul Rosenberg Associates for 
the USAERDL. during the past few years is 
indicative of this. The electronic geodetic con- 
trol ties, information sensing, and immediate 
transmission from the airborne vehicle to 
compilation center, electronic computation, 
stereoplotting and printing are all included in 
this automatic system. In this development, 
automatic recognition and discrimination be- 
4 
tween images of individual features has also 
been under study. This seems highly im- 
probable to achieve. However, if sensors can 
be developed with sensitivity of a sufficient 
degree to indicate differences in features 
electronically, computers of adequate storage 
capacity could make the idea possible. 
It is my understanding that the Stereomat, 
the Helava plotter, an Orthophotoscope and 
possibly other devices are being included in a 
development of an overall system. Early suc- 
cess from such approaches as these is highly 
desirable, but from the most optimistic view- 
point, considerable study and experimenta- 
tion. still lies ahead before practical applica- 
tion is possible. 
The one other step which is needed seems 
to be the ability to deliver the mapping data 
from where it is compiled to wherever 
needed almost instantaneously, and in a form 
most advantageous to the user. This also ap- 
pears difficult but since, in the developments 
that have been mentioned, all tend to convert 
information from graphic or visual to some 
electronic form, this step may be achieved 
with ease at some time in the future. 
In summation a few general points seem in 
order. From the research and development 
progress being made everywhere, mapping 
will be performed at a more rapid rate in the 
future. Perhaps present day techniques and 
equipment will seem as obsolete in the future 
as gathering images of the earth’s surface by 
plane-table compared to aerial photogram- 
metry today. But this will not occur over 
night. Components of a system, and even one 
overall system, may be produced which oper- 
ate automatically in a satisfactory menner, 
but until the system or systems have been 
thoroughly proven from the practical and eco- 
nomic standpoint, experience proven methods 
and equipment should be retained. 
REFERENCES 
a. Ester, R. D., “Automatic Contouring.” March 
1957. PHOTOGRAMMETRIC ENGINEERING. 
b. Rosenberg, Paul, ‘Information Theory and 
Electronic Photogrammetry.” September 1955, 
PHOTOGRAMMETRIC ENGINEERING. 
c. Bean, R. K., “Development of the Orthophoto- 
scope.” September 1955, PHOTOGRAMMETRIC 
ENGINEERING. 
d. Williams, R. E. and Paul Rosenberg, ‘The 
PRA TSS for Electronic Photogrammetry.” 
December 1956, PHOTOGRAMMETRIC ENGINEER- 
ING. 
e. Williams, R. E., “The Automatic Map Com- 
pilation System. March 1959, PHOTOGRAM- 
METRIC ENGINEERING. 
Hobrough, G. L., “Automatic Stereo Plotting.” 
December 1959, PHOTOGRAMMETRIC ENGI- 
NEERING.