International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004 
  
  
   
  
  
  
  
  
   
  
  
  
   
   
   
    
    
  
  
  
  
  
   
   
  
  
  
  
  
   
   
   
    
  
  
   
   
    
   
  
  
    
Marking 
The sights 
Setting up the 
instrument 
Topographic support 
Stereoscopic images 
Scannings 
Digital views with 
Nikon D100 
calibrated and 
mounted on the Laser 
scanner 
Operating methods for surveys of the three archways 
Topography-Photogrammetry 
Survey of the test area requires 6 stereoscopic 
models and the marking must be made to cover the 
entire object. This survey technique requires an 
aerial platform is necessary. 
The sights used for topography and 
photogrammetry are sights that can be collimated 
and recognized in the images. 
The principal characteristic is the verticality of the 
primary axis, made possible by the thoric level 
present in the instrument. 
The framing grids are the same. There are 32 
support points, located across the entire survey 
area. The points are distributed uniformly across 
the stereoscopic overlap areas of every model. In 
the event of interlinking models, the points are 
located in the overlapping area of the models. In 
the same way, in the event of triangulation to 
independent models it is necessary to put the 
transition points in the overlapping areas of the 
models. 
To cover the area, 12 photograms are necessary to 
form 6 models: 3 high models to carry out with an 
aerial platform and 3 low models to carry out from 
the street level. 
The images are defined as "normal" 
It corresponds to the stereoscopic images 
The main operating differences of the two methods used for survey are described in the table below. 
Laser-scanning 
Only a few points on the lower part must be 
marked to orient the scanning and only a single 
scan is necessary to cover the test area. In this case, 
the survey is done at street level. 
The laser scanner sights are the same as topography 
and photogrammetry but are supplied with a 
reflecting part to allow automatic extraction of the 
coordinates of the targets from the point clouds. 
Only the spherical level of the base is used to setup - 
the instrument. 
The framing grids are the same. The reflecting 
targets consist of 8 known coordinates and 4 
unknown coordinates located only at the level of 
the campaign range. The targets are positioned not 
only on the object but also in the surrounding area 
and are visible in the various scannings, thanks to 
the speed of acquisition and the possibility to 
survey with a very large angular range (360? in 
horizontal). This enables us to forego marking 
inaccessible areas. Instead of reinforcing the system 
of the models-scannings with points located on a 
vertical plane is reinforced with points on a 
horizontal plane. 
Terrestrial scannings 
It is done in three phases: 
a) panoramic scanning to verify the position and 
the exact coverage of the object, 
b) full-blown scanning (detail scan), 
c) scanning to very high definition of the 
individual markers (reflector scans). 
The camera is mounted onto the laser scanner and 
follows its movements. The internal and external 
orientation in the laser scanner system are known. 
The images are automatically taken at regular 
intervals registering the angular parameters of the 
laser scanner. As a result, the parameters of 
external orientation of the photograms are known. 
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