International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B3. Istanbul 2004 
  
The different items of PLP-CAM have to be synchronized 
exactly, because each systems works independently. The block 
chart in Figure 2 shows the approach. Using event markers 
solves the problem by generating time stamps. These markers 
are stored by POS and combine a measurement event with 
absolute GPS-time (e.g. starting a scanning line). 
   
  
  
  
  
  
  
3D-LS 
POS 
GPS ANTENNA 
mo 
æ Ivent Marker2 m 7 
A 
  
  
Ivent Marker 1 
  
  
  
Figure 2. Synchronization 
3. FUSION OF M1 AND 3D-LS DATA 
To investigate the fusion of panoramic and laser data first 
experiments were carry out in a laboratory environment. Here, 
only the panoramic camera M2 and 3D-LS were used. 
3.1 Experimental Set-up 
In order to study the problems arising by fusion of data sets of 
the panoramic camera and the 3D-LS, both instruments took an 
image of a special prepared scene, which were covered with 
well-defined control points. The panoramic camera was 
mounted on a tripod. After recording completion the camera 
was dismounted and 3D-LS was mounted on the tripod without 
changing the tripod's position. 3D-LS was used in the imaging 
mode scanning a field of view (FOV) of 40? x 26? comprising 
1600 x 1000 pixels. Each pixel is described by the quadruple 
Cartesian coordinates plus intensity (x, y, z, I). The M2-image 
covered a FOV of approximately 30? x 60? with 5000 x10000 
pixels. 
    
Figure 3. Special prepared laboratory 
508 
66 control points. were available in a distance of 6 m. Lateral 
resolution of laser and panoramic scanner is 3 mm and 1.05 mm 
respectively, which is a suitable value for fusion of the data sets. 
For the coordinate determination of the signalised points an 
independent approach was done. Using image data from a DCS 
460 camera and bundle block adjustment program Australis. 
The lateral accuracy of about 30 points is 0.5 mm and depth 
accuracy about 3 mm. 
    
Figure 4. PANCAM on tripod 
3.2 Modeling and Calibration 
Laser scanner and panoramic camera work with different 
coordinate systems and must be adjust one to each other. The 
laser scanner delivers Cartesian coordinates; where as M2 puts 
out data in a typical photo image projection. Although, both 
devices were mounted at the same position one had to regard 
that the projection centre of both instruments were not located 
exactly in the same position. Therefore a model of panoramic 
imaging and a calibration with known target data is required. 
X 
  
  
Figure 4. Panoramic imaging (see text) 
The imaging geometry of the panoramic camera is characterized 
by the rotating CCD-line, assembled perpendicular to the x-y 
plane and forming an image by rotation around the z-axis. The 
modelling and calibration of panoramic cameras was 
investigated and published recently (Schneider, 2002 & 2003, 
Klette, 2001 & 2003). 
For camera description and calibration we use the approach 
shown in Figure 4. The CCD-line is placed in the focal plate 
perpendicular to the z-axis and shifted with respect to the y'-Z 
coordinate origin by (y's,z'o). The focal plate is mounted in the 
camera at a distance x', which is suitable to the object geometry. 
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