Therefore, the stereo models of the previous and following 
strips are determined to be the best combination for the RPM 
from the viewpoint of processing cost. 
  
approach. Case (4) was confirmed to perform the processing 
within the same or shorter amount of time than when the RPM 
is not used. Based on this improvement, case (4) using the RPM 
and DTM as a reference, with only a high resolution in the 
coarse-to-fine approach, is deemed the most applicable method 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Aiea # of W/O All Stereo CUR Phy from a quantitative examination. 
Pts. RPM Models Strip FF Strips 
A 126 0.913 0.862 0.833 0.823 # of W/O 
: 2 
B 290 0.986 0.769 0.937 0.722 Area | pEMPrs. | RPM | e (3) e 
C 1049 0.877 0.739 0.836 0.799 A 668876 535 836 638 793 505 
D 730 0.752 0.646 0.736 0.698 B 786400 1149 1583 1275 1448 818 
E 1161 0.711 0.643 0.664 0.616 C 896213 1337 1735 1456 1610 821 
Unit : m D 961074 666 1667 1058 1273 740 
Table 2 The mean square of the elevation gap E 1000578 862 1936 1282 1516 910 
Unit : Second 
# of W/O All Stereo CUR PREV Table 6 Comparison of the processing times 
Area ; and 
Pts. RPM Models Strip ; 
FF Strips Mb ; 
3.2.0 Qualitative Evaluation 
A 126 15 13 14 14 ; 
B 290 106 89 97 89 An examination of the effectiveness of the RPM was performed 
C 1049 185 132 168 165 qualitatively by checking the distribution of the mismatched 
D 730 153 122 149 126 points on a color-shaded map created from the DEM extracted 
E 1161 263 239 253 232 using the matching process. 
(combinations of stereo models) 
Table 3 The number of mismatched points 3.22.1 Comparison based on the variations in the 
(combinations of stereo models) stereo model combinations for the RPM 
3212 Comparison of the restricted application of the The changes in the color-shaded maps with variations in the 
RPM in the coarse-to-fine approach 
For the use of the RPM with the stereo models of the previous 
and following strips, the changes in the accuracy of the DEM 
and in the processing times are examined using a restricted 
application of the RPM in the coarse-to-fine approach. The 
mean squares of the elevation gaps are shown in Table 4, and 
the numbers of mismatched points are shown in Table 5. 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Arca id SO (1) (2) 3) (4) 
A 126 0.913 0.823 0.924 0.941 0.769 
B 290 0.986 0.722 1.049 0.737 0.770 
C 1049 0.877 0.799 0.875 0.813 0.817 
D 730 0.646 0.698 0.663 0.629 0.680 
E 1161 0.711 0.616 0.679 0.604 0.624 
Table 4 Mean square of the elevation gap 
(Restriction in the resolution stage 
in the coarse-to-fine approach) 
# of W/O 
Area Pis RPM (1) (2) (3) (4) 
A 126 15 14 14 16 11 
B 290 106 97 106 88 90 
C 1049 185 168 186 152 157 
D 730 153 126 130 122 135 
E 1161 263 232 249 228 241 
Unit: m 
Table 5 The number of mismatched points 
(Restriction in the resolution stage 
in the coarse-to-fine approach) 
Based on Tables 4 and 5, compared to the cases without the 
use of the RPM, the accuracy of the DEM is improved with the 
application of the RPM for (1) all resolution stages, (3) high- 
resolution stages, or (4) when using the DTM as a reference. 
Table 6 shows the changes in the processing time with 
variations in the application of the RPM in the coarse-to-fine 
stereo model combinations for the RPM are shown in Figure 6. 
PREV and 
FF Strips 
Ortho W/O All stereo CUR 
photo RPM Models Strip 
       
   
    
0 500m (a)Mountain (area A). 
Aero photo by GSI Japan(2008) 
    
  
  
(b) Rice fields (area B) 
0 200m 
Figure 6 Comparison of elevation 
with RPM changing stereo model 
The squares in the figure indicated mismatched points in a 
mountainous area and rice fields generated without the use of 
the RPM. These mismatched points are removed by the RPM 
with a combination of all stereo models and only the stereo 
models of the previous and following strips. 
From a qualitative evaluation using color-shaded maps, the 
accuracy was confirmed to be improved from the use of the 
RPM when using combinations of all stereo models and only 
stereo models of the previous and following strips, which is the 
same result as from the quantitative evaluation. Also, for the 
distribution of mismatches, there are slight gaps between the 
two cases. 
170 
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