233 
curves 
i 
dR 
Fig. 8 - The estimated characteristic distortion 
curves and the Rollei calibration curve 
Cerfificate curve 
The Principal Point is estimated as intersection of 
straight lines passing through the distortion vectors 
making an estimation not very accurate, as can be seen 
in table 2. 
Fig. 9 - The estimated calibrated distortion curves 
versus the Rollei calibration curve. 
The test have been performed both with the non- 
corrected terrain co-ordinates both with those with the 
correction for relief displacement. The interpolation 
accuracy was as in table 1. 
Table 1-No relief displacement correction vs. 
correction 
Test 1 
Test 2 
Test 3 
<7q nocorr 
0.112 e-5 
0.113 e-5 
0.115 e-5 
(TQ with corr 
0.109 e-5 
0.108 e-5 
0.107 e-5 
Hypothesis 
testing 
Ho 
Ho 
Ho 
For instance in testl : 
• With no relief correction Sigma-naught = 0.112 
e-5 mm 
• With correction Sigma-naught = 0.109 e-5 mm. 
Making a hypothesis testing with a significance level 
of alfa= 5%, the null hypothesis is true. 
That means that the Flatness of the wall is not critical 
for the present conditions (for lack of planarity 
^ 1/2000 & for angle of field ^ 90°). 
Table 2 Results of the estimate 
DISTORTION COEFFICIENTS 
Ro=20.0 mm 
Ri 
r 2 
r 
Princ. point 
(mm) 
ROLLEI 
0.207e-4 
-0.97e-8 
? 
0.12 
-0.24 
TEST 1 
0.18e-4 
-0.99e-8 
-0.98 
1.75 
0.78 
TEST2 
0.21e-4 
-0.13e-7 
-0.98 
0.49 
-1.16 
TEST 3 
0.15e-4 
-0.86e-8 
-098 
0.69 
-0.63 
Ro=23.0 mm 
TEST 1 
0.24e-4 
-0.12e-7 
-0.97 
TEST 2 
0.26e-4 
-0.13e-7 
-0.97 
TEST 3 
0.21e-4 
-0.11e-7 
-0.98 
In this manner the found point is likely to be near to 
the point of best symmetry. 
The estimated distortion coefficients R1 and R2 are 
highly correlated (r = -0.97-f--0.98), so that the 
comparison with the Rollei coefficients is not really 
meaningful.