S.A.B. Kim
2 DATA
AL Each pair of SPOT stereo-images cover an area of 60 km x 60 km. Stereo-matching is an area-based one using the
epipolar correlation criterion (Kim, 2000). About 20 GPS measurements are used as ground control points. To save
computing time, stereo-matching is performed at every 5 pixel, thus the output resolution is 50 m. The stereo-match
results are transformed into elevation using a camera model by Orun and Natarajan (1994). Gaussian interpolator of
Kim et al. (1999) produces a DEM shown in Fig. 1a.
nted,
s that
iders,
Even
s are
buted
r not
ation
0 km
ints.
Fig. 1 Limitations of conventional interpolation methods (a) generated by Gaussian interpolator without intelligent
ation methods and (b) PCI DEM over a 60 km x 60 km area in Seoul/KyungKi region, S. Korea. The coast is on the left.
ning,
alues
ating | 3 CENTER-OF-GRAVITY (COG) AND EMPTY-CENTER-INDEX (ECI)
urac |
y COG and ECI are used to remove unrealistic outstretch of elevation along an image boundary. Interpolated values
Foley whose COG or ECI fail to meet threshold values are removed.
tered
0 km
ation
POT
villa PF
Iging oam e Y x
along | fis 3
|
'oast;
lified
total
idex)
lance . ARN % :
ed of [p iy)
I and
g the
ation,
This
ently Fig. 2 Illustration of ‘center-of-gravity’ (COG, left) Fig. 3 Distribution of COG (dotted) and ECI (solid) computed
their and ‘empty-center-index’ (ECI, right). ECI may be over a 35 km x 30 km area. The total number of COG (and
regarded as a 1D version of COG (1D being in the ECI) samples is 471,000.
radial direction). The shaded area is where stereo-
match succeeded, while the white area is not. The
outer circle indicates an interpolation radius.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B3. Amsterdam 2000. 497