International Archives of Photogrammetry and Remote Sensing, Vol. 32, Part 7-4-3 W6, Valladolid, Spain, 3-4 June, 1999 
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ERS ascending image ERS descending image 
ERS ascending ortho-image ERS descending ortho-image 
Fig. 11. Geocoding example of ERS SAR data acquired from 
ascending and descending orbits. 
4.4. MBC Example 
For the geocoded Landsat TM and the uncorrected SPOT input 
image of the Oetztal test area, a geocoding experiment using the 
MBC technique was made. Based on some tie-points manually 
measured in this image pair, a coarse relation between the data 
to be registered was established and was subsequently used in 
the image matching procedure. 
The result of coregistering the SPOT image is shown in Figure 
13. The matching accuracy was again determined by means of 
automatic image matching. The results are summarised in Table 
6. In comparison to Table 4 and Table 5 it can be seen, that the 
achieved accuracy for these data is superior to standard 
geocoding (see Table 4) and comes close to the one achieved 
after fine-registration (see Table 5). 
Table 6. Matching accuracy of geocoded Landsat TM and 
coregistered SPOT image after manual coarse 
registration 
East (pel) 
North (pel) 
Distance (pel) 
Mean 
-0.08 
-0.07 
0.58 
Std. Dev. 
0.55 
0.47 
0.42 
JERS-SAR reference image 
Fig. 12. Example of image-to-image registration through 
transformation of a geocoded JERS-OPS image to the 
geometry of a JERS-SAR image. 
The MBC procedure was also applied to the SPOT XS image to 
test the feasibility of fully automatic geocoding as pointed out 
in section 3.3.2. The SPOT image was first coarsely geocoded 
using initial imaging models and then coregistration was 
applied with regard to the geocoded Landsat TM image. The 
matching accuracy was again checked by image matching and 
led to the statistical values shown in Table 7. As it can be 
concluded from these values, the accuracy of such fully 
automatic geocoding can come close to the interactive method 
using parametric imaging models, provided again that the image 
data are sufficiently similar. 
Table 7. Matching accuracy of geocoded Landsat TM and 
coregistered SPOT image after automatic coarse 
registration 
East (pel) 
North (pel) 
Distance (pel) 
Mean 
-0.08 
0.02 
0.74 
Std. Dev. 
0.80 
0.62 
0.65