inbul 2004
0. 3, table
; the value
ages with
geometric
he images,
on, further
on for the
jared with
e a known
nage rays
way, the
mputation
t the two-
id 338m3.
e 4).
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
Zus Z ta, Mi Zu =Z, ) (7)
where Z,, mean value of the manually measured DTM
Lyi DTM-height no. i of the manually measured DTM
Zi DTM-height no. i of the destination DTMy
| rms [m] |
140.1
d images
para meters
334m2, 338m3
n of image
;tor 2x)
, we have
ese DTMs
{ap and a
a way that
n the two
in section
sht change
ent initial
Lommel-
tial DTMs
v, that the
our pixels
metres. It
rect result
je average
m scale factor
do height offset
. DTM parameter — | — Analysis and accuracy parameter
‘Scale factor m | Offset ay [m] | Iterations Zeim] | nus[m] —
Ta 0.0 4 -192 140.1
0.5 0.0 9 -84 [463
Ten 0.0 7 9.5 150.5
F 1 360.0 6 36.3 148.4
0.5 360.0 18 14.2 145.4
1 720.0 12 35.4 148.4
BS 720.0 ZF" 6 -| 1431 4
TS 1080.0 18 16.5 142.3
0.5 1080.0 16 214 143.6
RE 1440.0 29 11.6 AA ea
edit he: 1440.0 26 i1 LO d 11229.
nl 1800.0 17 1801.9 1807.9
0.5 1800.0 83 14.5 147.0
] 2160.0 10 21845...|] 21902
0.5 2160.0 18 2174.5 2181.4
Table 5. Radius of convergence using two images
4. CONCLUSIONS
The represented work on MI-SFS shows that the derivation of a
high-resolution DTM of real digital planetary images by means
of MI-SFS is feasible. The one-image and multiple-image
analyses are carried out using imagery from the lunar mission
Clementine. The obtained results shows that MI-SFS is a
method which is able to close the gaps in DTMs determined
with other reconstruction methods. Furthermore we show, that
the required initial values have a radius of convergence of about
four pixels (in this case of about 1440 metres).
The computation with one of the images was not successful. In
this case we developed a simple, and successful method which
modified the observed grey values. In order to do so, we also
needed an initial-DTM of the area, and although we have not
yet explicitly checked this assumption, we believe that we can
compute the grey value modification based on the DTM which
serves as initial height values for the whole approach.
In future we will intensify our investigations to simultaneously
process two and more images within MI-SFS. We will also try
to increase the geometric accuracy by introducing more
sophisticated object surface models (one times one pixel DTMs
with appropriate smoothness constraints, breakline and
occlusion detection modules). We also plan to integrate the line
sensor geometry into the algorithm, to use other planetary data,
€. HRSC data. In addition, the next important step is the
combination of image matching with MI-SFS into a combined
method. A precondition for such a combination is a separation
of the surface under consideration into parts with constant
albedo (MI-SFS) and into parts with variable albedo (image
matching). This task remains a challenge of the whole approach
Which we will try to tackle using texture analysis.
WI
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6. ACKNOWLEDGEMENT
This work was developed within the priority program "Mars
and the terrestrial planets" financed by the Deutsche
Forschungsgemeinschaft (DFG) under the project number HE
1822/10. The support is gratefully acknowledged. Thanks also
go to DLR for providing the Clementine data, and to the
employees of the ISIS Support Center at the United States
Geological Survey (USGS) for their aid in the radiometric
calibration of the Clementine images.