distortion and decentering parameters required; can effects be considered 
constant from one exposure to another; will a variety of cameras be used? 
One important aspect of multistation configurations is that they may, unlike 
aerial photographs, allow the determination of the three inner orientation 
parameters (hence the application of the method to the self calibration of 
close range cameras as indicated by Kenefick eft af (1972), K&lbl (1972), 
Bhatti (1973) and Faig (1975). This last feature may be of great value in 
certain close range applications, although the question remains whether 
the inner orientation can be considered constant for all exposures. An 
important advantage of multistation configurations is that the geometry of 
the set-up allows the determination of the self calibration (additional) 
parameters without the inclusion of any control information. In addition, 
the large redundancy present (Fig. 2) means that substantial sets of 
additional parameters can be carried without substantially reducing the 
degrees of freedom. 
The detection of gross errors should be an important aspect of any analytical 
work, but once again the stereophotogrammetric "norm" is lacking in one 
particular respect. Each image on a stereopair of photographs is related 
to a single epipolar line. Any error directed along such lines will not be 
detectable (unless associated with a control point) because ray intersection 
still occurs (Fig. 3). Such an error will result in the object noint being 
incorrectly positioned in its epipolar (basal) plane. (This is why, of 
course, in "conventional" photogrammetry y-parallax indicates a relative 
orientation error whereas x-parallax does not.) 
1004 ; 
50 
redundancy (r) 
  
  
  
T V T T T v T 3 ', T ' T T 1 T 
5 10 
number of object points (nj) 
Fig. 2 Redundancy in a multistation configuration without any control 
information (ie. a multistation relative orientation). It is assumed that 
all Np object points image on all photographs. ng is the number of 
photographs. Note that the minumum number of points required is four if 
Ng> 3. 
239