+10 
  
  
  
  
-10— 
  
Fig. 3. Total lens distortion curve for the unit Aviogon camera + infra filter 
determined by means of the "y-parallax method", applied to two consecutive pairs 
of stereoscopic pictures. 
3.3 Vertical Parallaxes 
When dealing with a pair of stereoscopic pictures with certain lens 
distortion, it may be stated that co-pertinent rays in the two pictures 
originating from a point on the object intersect no longer when the 
pencil of rays in the stereo-instrument is reconstructed but cross in 
space. Thus, in the intersecting plane illustrated in fig. 4, a discrepancy 
will result in a parallax p which be divided into the horizontal compo- 
nent p, and the vertical component p, [14]. 
By means of vector symbols this relation may be written [11]. 
— => — 
D DL D tutte Soa (1) 
^ ^ 
If the unit vectors are symbolized by p, and p, we get 
— —> A 
P | P, | Ph 
> + AU S RN. di Wit ul (2) 
and p, = |p, | "P,