The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B5. Beijing 2008 
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Figure 4. Spatial intersection of multi-perspective panoramas 
3. DATA ACQUISITION AND 3-D MAPPING TESTS 
Experiments were performed under different situations to test 
the system as well as determine the optimal configuration of the 
camera as to exposure time, aperture and other parameters. 
For example, when taking pictures outdoors, exposure time can 
range from 8,000 ms to 20,000 ms according to actual weather 
conditions. For indoor image acquisition, a 30,000 ms exposure 
time is usually selected. And under fluorescent lights, a 
fluorescent-cut filter is used on the camera lens. Sample 
panoramas taken with the prototype are shown in Figure 6. 
Figures 7 and 8 show examples of a preliminary 3-D mapping 
test using a pair of 180° stereo panoramas that cover an area of 
relatively simple terrain (Figure 7). Image matching was 
performed using cross-correlation followed by a Least-Squares 
Matching. After corresponding points were found, ground 
positions were calculated using Equations 4 and 5. 
Consequently, a DTM was generated by Kriging interpolation. 
Then an orthophoto was produced by back-projection using 
Equation 4. The derived mapping results are shown in Figure 8. 
The calibration of the camera is pending at this time. 
(a) Left-eye view (b) Right-eye view (c) Spatial intersection 
Figure 5. Top view of the stereo geometry 
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P** 
v - 
(a) Desert site near Reno, Nevada 
(b) Ohio State University Stadium 
Figure 6. Sample panoramas taken with the prototype 
■HI 
(a) Left panorama ( 180°) 
(b) Right panorama (180°) 
Figure 7. Partial stereo panoramas used for 3-D mapping