{ e] { X Yn Zt i JA } 
21 
where: n = 1f,...,N > - number of ground control points, 
t — line number, j - pixel possition in the line Cimage 
visualization is required for determination of these 
coordinates). 
The set of coordinates X n° Yan? <n CD TM of freely distributed 
points Cwhich inform about terrain relief) is denoted as: 
{x} = {* tw 2) 
where: m - 1,...,M - number of DT M points. 
The terrain relief information < T given by interpolation 
using two dimensional third order splines [Zavijalow 1980]. 
&.1. Correction functions 
For the images to be corrected two empirically established 
functions are used [Pyka 1985]: 
a2 basic 
dX'zs f CX',Y'2 - A * AX'- A Y'« AX" “+ AX'Y + AY? + 
x o 
1 e 4 5 
Cia 
T » 3 » 2, 9 2 » 2 ‚+ 
+ AgX + AX v. AX Y’ 5+ AX "ev 
9? om 9 ? Um » » »2 » ? » 2 
dY £ CX Y B5* B,X * BY + BX + BX Y°+ BY + 
3 2 3 2,,2 95»2 4,,9 Cru» 
* BgX + BOX Y'« Bg! * BX Yt. B,oX y. B, ,* ¥ +... 
where: dX’, dY' - corrections changing pixel possition Con the 
reference plane shown in Fig.1) to correct place Cpoint R', 
X', Y' - ground coordinates calculated according to the 
collinearity equations for scanner imagery [Konecny, 19711, 
using exterior orientation data ,<Q and image pixel rdi, jd 
coordinates à and / of control points. 
bd) auxiliary 
t =F CX,¥YD =C.-C,X -C.Y - CX?’ - C xy - cy? 
x 1 4 
O 2 3 5 
2 y Cæ2ad 
- Cet - CX Y 
Se ; = " 2. a 2 n. 
J ED Do D,X D_Y Dx D XY DAY 
8 a 8 2,2 can) 
Dex - DR Y - DgXY - Dx y iv 
X,Y-ground coordinates of control points determined in set ORO 
The coefficients A,B,C,D of basic and auxilliary correction 
functions are obtained by least square solution of equations 
C15 and (2) for N ground control points. 
Registered during the flight attitude parameters Cexternal 
orientation elements) are not errorfree and have systematic 
character [Schuhr and Konecny,1984]. Therefore, simple formulae 
C10 can be used satisfactorily for computation of correction 
vectors dX'dY; and to eliminate the errors from the data <Q 
121