MULTISPECTRAL AERIAL PHOTOGRAPHY AS AN IMAGE 
INTERPRETATION TRAINING AID 
Theodore C. Vogel 
U. S. Army Engineer Topographic Laboratories 
Fort Belvoir, Virginia 22060 
Introduction 
Broadband multispectral or multiband photography can be defined 
as isolating the electromagnetic energy reflected from an object or 
scene into a given number of spectral bands and recording each sepa- 
rately on black and white film*. Operationally, multispectral 
photography requires a number of basic tasks not common to conven- 
tional aerial photography: (1) color separation, accomplished during 
acquisition; (2) film processing and generation of film positive; and 
(3) recombination of the film positives in an additive color projec- 
tion system. Analysis of multispectral photography usually occurs on 
the viewing screen and not from a photograph. 
This method of aerial photography is credited to Clark Maxwell 
who in 1861 discovered that visual perception of a color could be 
simulated by the correct mixture of three different light sources, 
blue, green, and red. He also demonstrated that these primary 
colors could be mixed in varying proportions to produce every color. 
Purpose: The purpose of this paper is to identify and describe an 
existing aerial photographic acquisition system that is capable of 
producing multi-film/filter photography for use as image interpre- 
tation keys and interpreter training aids. 
Background: With the increased reliance placed on aerial imagery as 
a method for the collection and evaluation of terrain and environ- 
mental information, the number of well-trained image interpreters 
has dwindled to the point where the demand has far exceeded the 
supply. Although the development of computer-based, automated image 
data extraction systems has and will in the future greatly alleviate 
this situation, humans still function as the "workhorse" for obtaining 
information from aerial imagery. With the wealth of different film 
and film/filter combinations available today, in conjunction with the 
  
1 p. .6. Orr, "Multiband Color Photography," Manual of Color Aerial 
Photography, Smith and Anson, Eds., American Society of Photo- 
grammetry, p. 444, 1968.