(drv)y vertical parallax of the distortion in the left-hand 
picture 
dr h the distortion of the right-hand picture 
(dr h ) H horizontal parallax of the distortion in the right-hand 
picture 
(dr h ) v vertical parallax of the distortion in the right-hand 
picture 
(dr) H the sum of horizontal parallaxes in a pair of pictures 
(dr) v the sum of vertical parallaxes in a pair of pictures 
The curvature of the earth is assumed to be corrected according to 
formula (6): 
B 
B 
In a pair of pictures with the centre-points 0/ — ^ and 0/ + 2 
we have: 
dr 
V 
(7) 
B 
2RH + x 2 + (y + -y) 2 
B 
B 
B 
dr v(y + Tp 
) [x 2 + (y + 2 ) 2 ] 
(dr v )„ 
B ( 7 h > 
2RH + x 2 + (y 4 y ) 2 
B 
dr v • x 
B 
x [x 2 + (y + y) 2 ] 
B 
2RH + x 2 + ( y — y) 2 
(8) 
489