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PHOTO INTERPRETATION PICTURE, COLWELL 99 
scarcely be discerned by a ground observer; furthermore they are far more readily seen 
on this photography than on conventional high altitude photography. 
Colwell (1956) has demonstrated that for certain types of photo interpretation it is 
desirable to obtain either still or motion picture photography from low altitudes and 
  
Fig.6. An example of the image enhancement made possible by LogEtronic 
printing (right photo) in contrast with conventional printing (left photo) 
from the same negative. For further details see article by Craig (1955). 
(Photo courtesy LogEtronics, Inc.) 
from precisely situated camera stations. When attempting to obtain such photography 
from fixed wing aircraft, he found that their relatively high rate of travel and limited 
maneuverability posed serious problems in (1) framing the target properly, (2) photo- 
graphing it from the correct camera stations, (3) minimizing image blur, and (4) ob- 
taining sufficient overlap to permit either stereoscopic or motion-picture viewing of the 
photo images. He found that each of these problems could readily be overcome through 
employment of a helicopter, or in some instances a dirigible, as the aerial camera plat- 
form. The main advantage of the helicopter was its greater maneuverability, permitting 
  
  
  
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