International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B3. Istanbul 2004 
4.2 Generation of a Composite True Orthoimage 
True orthoimages can be synthesized into one composite true 
orthoimage where occluded areas of one image are 
compensated with other true orthoimages. For each pixel 
coordinates (/, /) , Composite true orthoimage /orth(i, j) can 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
be created from true orthoimages /orth, (i, j) with the following n 
equation: 
S Wi, j,k) x lorth, (i, J) 
lorth(i, j) = A— — KE 
Zw, ik) 
k=1 | 
where w(i, j,k) is any proper weight function which satisfies: AB 
lorth, (i, j) 2 0 2 w(i, j,k)=0 Coc 
coll 
5. TEST AND RESULTS m 
atc 
The algorithm has been tested with aerial images and digital of h 
map data shown in Table 1. Building polygons are extracted refe 
from LIDAR data automatically (Oda, K., et. al., 2004). The top eme 
three images in Figure 6 shows original images. True 
orthoimages are shown in Figure 6 (2), where occluded areas a 
are filled with black colour. Figure 6 (3) shows the composite figu 
true orthoimage where occluded areas compensated with other acci 
true orthoimages. For this sample with 1589 x 2797 pixel?, 
processing time of the true orthoimages is 1.25min per image INT 
with a Pentium 4 processor. The composite image is 
synthesized from 6 true orthoimages and its processing time is i 
0.66min. 
pop 
Table 1. Data used in the test. Rav 
Items Attributes thes 
Target area Shinjuku, Tokyo(1.2kmx600m) basi 
Aerial Number/Courses | 30 photos / 3 courses nav 
Images 1/8000 ah: 
(80% overlap and 60% sidelap) "e 
Scale 1/8000 lin 
Overlap/ Sidelap | 80% / 60% 
Features on the | DEM created from LIDAR data qua 
ground 
Digital | Features above | Building polygons automatically The 
map the ground. extracted from LIDAR data and esti 
edited with a digital stereo Hiat 
plotter (Oda, K., et. al., 2004). esti 
EPI 
the 
.References 
Oda, K., Takano, T., Doihara, T., and Shibasaki, R., Automatic mez 
Building Extraction and 3-D City Modeling from LIDAR data in : 
Based on Hough Transromation, ISPRS2004, Commission III, info 
PS WG III/8. rece 
GPS 
mox 
Her 
inst 
mea 
the 
(3) Composite true orthoimage con 
Figure 6. A sample of true orthoimage generation. xd 
626