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bundle adjustment after measuring the machine coordinate
with the precise measuring instrument of coordinate. After
choosing 1 model of the photographs taken by making the
fight altitude different, we calculated 3 dimensional
coordinates about 8-15 ground object points with 4 ground
control points per model, and table 2 is the RMSE about
ground object points at each flight height.
Table 2. RMSE according to flight height
RMSE(mm)
X Y Z pT
22.9 18.3 92.7 97.2
34.6 223 884 97.5
435 31.4 207.0 213.8
59.4 55,1 334.1 3437
870 87.3 528.9 5430 |
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100 150 200 250 400
Height(m)
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Figure 2. RMSE according to flight height
To illustrate this after comparing it by flight height, it is
like the figure 2. The reduction rate of positional error(P) of
the result measured from the photo taken by lowering the
altitude of about 24%, 40% and 54% with 200m, 150m and
100m on the basis of the flight height, 250m was about
38%, 72% and 72% respectively. And, in case of
photographing by rising the altitude to 400m, the increase
rate of RMSE of about 60% is showing. To compare this
by classifying plane error(X, Y) and positional error(P), the
difference of plane position at the flight altitude, 100m was
about 29mm, and the positional error was about 100mm.
Table 3. RMSE of ground object points
height | endlap RMSE(mm)
(m) (26) X Y Z P
80 471.317. 1645 1740
70 336. 180 771... 86.0
Ee 60 225 158 55.1 615
[o d . 50 21) 146 416 488
80 594 55.1 3341-3386
250 70 332. 293 1754 1809
60 263 187 1537 1571
Ev d mx 227 166 1433 1460
In case of photographing by rising the flight altitude to
about 30%, 60%, 120% and 250%, the increase rate of
RMSE of plane position showed about 40%, 80%, 180% and
300%, and the increase rate of positional RMSE showed the
bigger aspect in comparison with the increase rate of
RMSE of plane. Thus, it can be seen that the flight
altitude has big influence on accuracy. In case the flight
altitude, 250m, the scale limit to consider only plane
accuracy was 1/500, and the scale limit to consider space
accuracy was 1/2000. And, in case of the flight altitude,
400m, we could obtain the map of scale, 1/700 and 1/3000
in accordance with plane accuracy and space accuracy. So,
with the photography within the flight altitude, 400m. that
the naked eye control is possible also, we could obtain the
geography information of large scale which is demanded.
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Figure 3. RMSE according to the endlap(h=150m)
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End lap (%) (Height = 250m)
Figure 4. RMSE according to the endlap(h=250m)
Table 3 is the result to have calculated 3 dimensional
coordinate of 5-10 ground object points with 3 GCPs and
to have extracted the RMSE about 2 photos photographed
by making the endlap different at the flight height, 150m
and 250m respectively. Then, to compare and illustrate this
is like figure 3 and figure 4. As the result to have
- measured the photo taken by reducing the endlap by about
10% from 80%, the RMSE is showing the tendency that
about 44%, 65% and 72% reduce.
This shows that the accuracy of point positioning is
improved according as the rate of height of base line(B/H)
for photography increases. Then, in case of aerial
photography, the endlap over 50% is essential as the ideal
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996
