(U,V, W) : 
/\Camera Station 
cV 
       
  
(S,T,0) 
Principal pt. 
Appendix A 
STEREO BLOCKS 
  
  
d 
SI^ 
T 
  
  
  
  
Sá 
  
  
  
  
  
—— > 
1" Strip 
direction 
  
  
  
  
  
  
  
  
  
  
  
e photo pts 
® principal pts (unobserved) 
used as "dummy" photo pts 
  
space angle subtended at 
air station, giving one 
observation equation. 
"Exploded" stereoblock diagram 
4. For a block of n strips each of m photos, there are:- 
m(n+1) photo pts 
mn camera stations 
mn principal pts 
2. If h of these are height control points and k are ground 
control points, then:- 
a) if the points are held rigidly at these values, 
there are in all 
n(11m-8) observation equations in the remaining 
m(8n+3)=-h-2k variables; 
b) if the points are allowed to vary, but are kept as 
close as possible to these values, there are now:- 
n(11m-8)+h+2k observation equations in all m(8n+3) 
variables, 
or c) if some are held rigidly (e.g. ground control) 
while others are held as close as possible 
(e.g, height control), the result is something 
between the two previous situations. 
In any case, the framework is over-rigid by (3m-8)(n-1!)*h*2k-8 
conditions.