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accuracy of different resolution images, a sampling experiment
of different resolution images is performed. In this experiment,
other than continues sampling, only the integer sampling is
considered. The MS image pixel size is 16 times of PAN image
pixel size. Figure 1 from case 1 to case 10, 10 figures show
different sampling error of comer. The equal probability of
sampling error is supposed. The statistical result is showed in
table 1.
• Center in PAN image
• C enter in MS image
i-i MS image
□ PAN image
® Ground object
É$ Object extension
Case 4
Figure 1, Sampling error of corner, case 3 and case 4.
■ C enter in PAN image
• C enter mMS image
!_J MS image
□ PAN image
Ground object
Obj e et e xtension
Case 9 Case 10
Figure 1, Sampling error of comer, case 9 and case 10.
Table 1 shows that the average sampling error of comer is 2.82
pixels (PAN).
No
Deviation
Probability
1
3.53
1/3
2
3.53
1/3
3
6.78
1/3
4
0.71
1
5
1.58
1/2
6
3.81
1/2
7
2.91
1
8
1.58
1
9
2.55
1
10
3.53
1
11
3.53
1/3
12
3.53
1/3
13
4.95
1/3
Weighted mean deviation=2.82 (pixels)
Table 1. Sampling error of comer and its probability
Figure 2 shows the different sampling error of gravity center in
different situation. The statistical result of sampling error of
gravity center is showed in table 2.
■ Center in PAN image
• Center in MS image
l-i MS image
□ PAN image
S Ground object
Figure 2, Sampling error of gravity center, case 1 and case 2.
Table 2 shows that the average sampling error of gravity center
is 1.12 pixels (PAN). This figure is much smaller than that of
comer by 60 percent. That means the gravity center is more
suitable than comers to be used as tie points, because the
gravity center has higher geometric accuracy than comer.
