(514) 
Lens Lens 
q 
  
  
  
  
  
  
  
  
Left hand photo 
N 
NEight hand photo 
Fig. 1. 
EXPLANATION OF FIGURE 1. 
This figure is an isometric drawing of the two photographs of a stereo pair, showing 
the spatial relationships of uy and ,. These two points are chosen instead of u and (Figure 3) 
because all displacement of uj is in the direction of dip, and the proof of the various 
relationships is greatly facilitated. 
This figure emphasizes the relationships on the left-hand photograph. 
The following are definitions and explanations of the various lines and points: 
c, photo center of the left-hand photograph. 
c, photo center of the right-hand photograph. 
b, adjusted photo base, based on the elevation of 1. 
f focal length of the camera lens. 
u, theoretical point in space, corresponding to U,, of Figure 2. 
u, photo position of us on left-hand photograph. 
k photo position of u, on the right-hand photograph. 
u, corrected horizontal position of u_ adjusted to the datum plane passing through. 
u,u, or dh the difference in height between 1, and u». 
ku, or dp the difference in parallax between 1, and u,. 
u,u, the net radial displacement in direction of dip u_ on the left-hand photograph, 
based on the datum plane passing through. 
u, k the net radial displacement in direction of dip of u_ on the right-hand photo- 
graph, based on the datum plane passing through. 
je constructed equal and parallel to ku,. 
jk constructed equal and parallel to c, 1,. 
From equation I and from the given equality of bı + dp = bu the follow- 
ing equation is derived. 
AD dp 
(bs dpud b» 
(Equation II) 
To solve for dh in equation II, the difference in parallax between u and |, 
and the adjusted photo base (either bu or bi) must be known, as well as the 
focal length (f). 
dh =- 
  
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Us