THE MODEL FOR DIGITAL GEOMETRIC RECTIFICATION 
The mathematical model represented in chapter two can 
successfully be used for digital rectification. To recon- 
struct the unknown exterior orientation parameters a least 
squares adjustment is formulated with two groups of obser- 
vation equations according to equations (5) and (6). Each 
control point leads to two observation equations of the 
following type: 
  
  
  
  
  
0 3 o 9 9 9 
N XS o Yo ea i * 
| 9X3 9X; 9 Xi 9X; 
| = Au, + s. A rgo CN. t cuc AX k + 
| eri an. rig axi ALCUN (7a) 
| ay k o; al: o» 
| 0, o,k 
| a o o 9 0 
| i * yao SB E oF, od, 0 
| 
| Yi ay, yi yi 
— ^ Auk + 5 Ad + o AK, + oi. AX k + 
30; de. "Kr roc aX os 
k Pk k o,k 
alat e MAT (7b 
4x. kt 7g Moxc yi ) 
T , 32 , 
o,k o,k 
Equations (7) are derived from equations (5) by Taylor 
extensions. Vxá and Vy; are the residuals of the image 
coordinates x and y which are assumed as the observations 
of the adjustment. 
Interpreting the n, as fictitious observations of amount