pretation and integral interpretation. Details are listed in Appen 
dix 1. The experimental work will be completed in the near future. 
"International" Test 
The "international" test is a project of the 
Working Group "Experimental Research in Photo-Interpretation" of 
Commission VI of the International Society for Photogrammetry 
/V, /3/. 
The work is performed according to the integral interpretation 
method. Details are listed in Appendix 2. 
OUTLOOK ON' FUTURE TASKS 
The mathematical description of the two interpretation methods 
shows the need for further development. Among others, the introduc 
tion of a concept of value into information processing seems neces 
sary if (what is to be aspired after) the concept interpretation 
result is to be understood as the number and value of the single 
interpretation data. First general mathematical formulations as to 
this matter are already available /4/. The results obtained by the 
aforementioned experimental work are considered an adequate data 
material for a theory still to be developed in this connection. 
Apperception of image content, image processing, and automated 
photo-interpretation are additional tasks the performance of which 
should be pushed forward. 
Apperception of Image Content 
Each photograph can be broken down into a finite number of areas 
of a certain tone ("tonal areas"). However, on a photograph we do not 
"see" tonal areas but we see "gestalten" (image gestalten) / 5 /. In 
recognizing these image gestalten, we must differentiate between the 
recognition of form and the recognition of meaning. Further parameter 
important for the process of interpretation are: the application of 
analogue arguments, the "attitude" of the interpreter, the influence 
of the given objective upon the interpreter, etc. /6/. Since the 
photograph is the starting basis of each interpretation, fundamental 
research in photo-interpretation should turn its attention at a still 
greater rate to the question: 
How does the human being looking at a photographically recorded 
image absorb the content of the image i.e. how does the appercep 
tion of the image content function (particularly in case of an 
aerial photograph)? 
We hereby have to examine whether single components of the evidently 
very complex process of apperception should be or must be considered 
in the further development of the methods of photo-interpretation. 
Furthermore, the process of apperception will probably be an impor*- 
tant, if not an essential basis of automated photo-interpretation 
aspired after. In the sense of informatics, we are confronted here 
with a system the efficiency of which surpasses by far all hitherto 
known technical systems of information acquisition and information 
processing.