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The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008
Figure 2. ASTER image and control points for correction
Figure 3. SPOT5 image and control points for correction
Figure 4. IKONOS image and control points for correction
After selecting control points, correct original image by
quadratic polynomial method for correction, and resample by
Nearest-neighbor, then select 16 control points in ASTER image,
16 control points in ETM, 16 control points in SPOT5, 18
control points in IKONOS. Research on the corrected points
precision in different types of remote sensing images, through
compare the test points coordinate in topographic map with the
corrected images. The result can be referenced to Table 1.
Method of
correction
ASTER
ETM
SPOT5
IKONOS
Nearest-
neighbor
25.0m
27.8 m
20.9m
6.7 m
Table 1. the corrected points precision of four remote sensing
images
2.2 Research on precision of geometric correction of remote
sensing images by data of portable GPS.
Obvious ground features are selected as portable GPS control
points, select obvious cross junction etc. 22 control points in
sum, for geometric correction of ASTER, ETM, SPOT5, and
IKONOS, the ways are ditto (except Nearest-neighbor), the
correction images are omitted. Then select 22 control points in
ASTER image, 21 control points in ETM, 18 control points in
SPOT5, 18 control points in IKONOS, evaluate the point
precision of the selected points which are considered as test
points, the detailed result can be referenced to Table 2.
Method of
correction
ASTER
ETM
SPOT5
IKONOS
Nearest-
neighbor
20.0m
25.7 m
23.8m
10.1 m
Table 2 .the precision result of correction by data of portable
GPS
Compared with the corrected points precision of calculated
control points in topographic map, for ASTER and ETM image,
the corrected precision is a little higher by data of portable GPS,
it shows that the control points are collected by portable GPS
can replace calculating on 1:50000 topographic map; however,
for SPOT5 and IKONOS image, the corrected precision is lower
by data of portable GPS. So it is not suit to use surveying
control points by portable GPS as correcting SPOT, IKONOS
images.
2.3 Research on precision of geometric correction of remote
sensing images by data of GPS for specialized.
Collect 26 control points in field by GPSRTK (Trimble5700),
and select 16 of all to make geometric correction for ASTER,
ETM, SPOT5 and IKONOS images, the ways are ditto. Then
select 21 control points in ASTER image, 17 control points in
ETM, 15 control points in SPOT5, 16 control points in
IKONOS. Evaluate the point precision of the selected points
which are considered as test points, the detailed result can be
referenced to Table 3.
Method of
correction
ASTER
ETM
SPOT5
IKONOS
Nearest-
neighbor
17.9m
22.4 m
13.2m
4.8 m
Table 3. the points precision of correction by data of GPSRTK
Compared with the corrected points precision of calculated
control points in topographic map, the corrected precision are
all improved by data of GPSRTK, but the improved level of