eaa te a aaa is lo e iot ud asa Rt Ri Rl iia 
d t VOR RAM, ro 
t Bs si 
bhai ital 
Asad: 
sip x 
  
  
   
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
   
   
deformations will thus be eliminated at the absolute ori- 
entation. This is, however the case only when we deal with 
near vertical pictures of a rather even ground. If there 
are large elevation differences in the model, or if oblique 
photography is used, the deformations in the model will 
not be completely eliminated by the absolute orientation. 
Similar conditions are also found in terrestrial photo- 
granmetry. À careful centering of the images is of impor- 
tance to the aerial triangulation, and this operation im- 
plies & condition, which has to be taken into account for 
the performance of correct adjustment procedures. 
From several points of view it is desirable to have 
a convenient and well defined method for the adjustment 
of the discrepancies, which arize in the centering pro- 
cedure, The images are, to begin with, empirically centered 
in the projectors. The discrepancies may then be measured 
in the instrument as x- and y-differences. The adjustment 
of the discrepancies is then executed in accordance with 
the method of the least squares. From the general solution 
of the normal equations, such corrections to the transla- 
tions, the rotations and the image scale are obtained, that 
will reduce the square sum of the residual x- and y-diffe- 
rences to a minimum, In this way, it is easy to control 
the accuracy of the empirical adjustment at the centering 
of the images. From numerically computed corrections to 
the degrees of freedom, corrections to x- and y-parallaxes 
of the model can easily be found. 
If the fiducial marks are placed in the corners of 
the image, as is for instance the case with the Wild RC 5 
camera, the adjustment of the discrepancies according to 
the method of the least squares gives the following cor- 
rections to the four degrees of freedom (see fig. 1) 
ax, = zfs 
ay,