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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004 
S. EXPERIMENTAL RESULTS [ r 
741400 
The LIDAR data used in this research covers an area in Hsin- e: 
Chu Science-based Industrial Park of north Taiwan. The data | 
was obtained by Leica ALS 40 system. The discrete LIDAR 2741300 | 
points were classified into ground points and surface points | 
previously. The average density of LIDAR data is about 1.6 | 
     
   
   
   
         
    
      
pts/m°. The ground resolution of QuickBird multispectral jv 
satellite image and aerial image are 2.8m and 0.1m, respectively. | 
The related parameters are shown in Table 1. 2741100 | 
In building detection, the surface points and ground points from en 00 ber uu us 
LIDAR data are rasterized to DSM and DTM both with a pixel 250400 250500 260600 250700 250800 250900 251000 251100 
size of 0.5m. The DSM and DTM are shown in Figure 6 and Figure 7. Digital terrain model 
Figure 7. The QuickBird multispectral image and aerial image 
are rectified into orthoimage by using the LIDAR DSM. The 
orthoimages of QuickBird and aerial photo are shown in Figure 
8 and Figure 9 respectively. The segmentation result is shown 
in Figure 10. The classification result is shown in Figure 11. A 
1/1000 scale topographic map was used to evaluate the 
classification results. The 1/1000 topographic map is shown in 
Figure 12. As we compared the classification results and 
topographic map, most of the building regions are accurately 
extracted. The small buildings are normally with low elevation 
and less texture information. Hence, most of the undetected 
buildings are the small ones. Considering different land covers, 
the classification accuracy is 94%. On the other hand, if we 
only considered buildings, the detection rate is 8196. The 
accuracy performance is demonstrated in Table 2. 
   
d 
   
  
  
  
  
  
  
Table 1. Related information of test images Figure 5, Aerial age 
LIDAR Optical Images 
Leica ALS40 Aerial QuickBird 
Image Image 
Acquire 2002.04 2002.03.20 .. 1.2002.10.17 
Date 
Resolution | 0.8m/point 0.1m/pixel 2.8m/pixel 
Data l.Surface points | color image | multispectra 
2.Ground points | image 
  
  
  
  
  
2741400- 
2741300 
  
2741200 
2741100 
    
2741000 A 
250400 250500 250600 250700 250800 250900 251000 251100 
Figure 6. Digital surface model