3.5 Relative Orientation 
At least two pairs of parallel vectors are available at each 
photograph. As a pair of parallel vectors defines a plane, the 
relative orientation of two metric images_ can be calculated as 
recommended in 2.1 /2/. As the vectors vi, Vi and v2, Va do not form 
the same plane, it is suggested to use those vectors whose plane lies 
vertically or horizontally at the object. So the reference system is 
equivalent with a local geodetic system (Fig. 7). 
  
  
Fig. 7: Two reference systems defined by pairs of 
parallel vectors 
4 PRACTICAL TEST 
As test object the building of the ‘Vienna Music Association’ was 
chosen /5/. Four pictures vith the numbers M2, M4, M5, M6 were taken 
with a Hasselblad EL camera which has an image format of 6 x 6 cm. 
The image coordiantes of twelve object points (Fig. 8) were measured 
and transformed to the center of the photograph. The results of the 
interior orientation calculated by the methods described in this paper 
are given in Tab. 1: 
  
INTERIOR ORIENTATION SPECIFICATIONS 
  
  
Xo Yo Co photogr. points method 
(mm) (mm) (mm) 
0.00 0.00 49.49 M4 M5 M6 1,2,13,14 2.2 
0.00 0.00 50.86 M4 M5 M6 -- It -- 3.3 
1.42 -0.06 50.48 M2 [9 30 i015 3.3 
0.00 0.00 50.66 M2 15,16 3,3 
0.53 -0.36 50.57 M2 free 3.3 
0.00 0.00 51.29 M2 12,13,14 3.3 
0.40 -0.32 50.63 M2 1,2,9,10,11,12,1* 3.3 
ie 
-0.19 -0.69 51.81 M2 M4 M6 1,2,3,4 3.3 
  
  
  
  
  
- 537 =~