2 
In all such cases, the photogrammetric technique is not and can not be 
strictly conventional. The geometry of the projection cannot always be 
central perspective and the application cannot be related to mapping or 
surveying. These throw out newer challenges. However, inspite of the 
non-conventional nature, the general working system is similar to the 
topographical applications (see Fig 1). 
  
INPUT (Object) Object 
Control* 
+ 
DATA ACQUISITION Camera (+ CRT*,Sensor*,etc.) 
+ 
Instrument 
Model (Opto-mechanical, Digital) 
DATA PROCESSING (Data: 1, 2 or 3 dimensional) 
AND ANALYSES + 
| Computer* 
OUTPUT (Information) Graphical, Numerical, Statistical 
  
  
  
Note: Items marked * may be optional in some cases 
Figure 1 : The General Working System, Chain of Operations 
WORKING SYSTEMS 
The general working system and the chain of operations are given in 
Fig 1. Between the Input (object) and the Output (information) in the 
working system, one passes through the Data Acquisition and the Data Pro- 
cessing & Analysis phases. It may be noted that in the data acquisition 
phase, the provision of control (and the associated cost-considerations) 
in the classical topographical sense may not be required generally. Like- 
wise, in various applications one may not require mensuration instruments 
at all; ie., direct graphical and qualitative information may be adequate 
for such applications. Furthermore, computer utilization may not be 
needed in many cases of data processing. Yet, one of the major trends in 
the development of non-topographic applications of photogrammetry during 
the past several years has been the increasing use of electronic comput- 
ers for data processing. The computer utilization can be viewed in the 
following (for further interesting ideas, see Wong [11); 
Data Collection: 
1) Digitizing existing charts obtained from analogical/graphical 
photogrammetric techniques; 
2) Measurements of photo-coordinates at a comparator; or 
3) Digitizing spatial coordinates from a 3-D (stereo) model at a 
stereoplotting instrument (also analytical plotter).