Figure 6 
In the orientation phase, the results obtained are compared with 
the results of the images corrected by distortion while using the 
original images; the software used, considering the calibration 
certificate in the interior orientation, enables comparison of the 
different residues in the calculation. 
The portion done to this point has envisaged carrying out the 
survey only in the area of the floor of the right nave, in order to 
test out techniques, methods and solutions. 
The diagram of the shots taken of the photogrammetric block is 
grouped into three strips made length-wise in the nave; the 
individual photographic shots have been done with the camera 
mounted on a mobile tripod, at a height of about 2.5 m (Figure 
7) which gives the starting images, where one pixel is equal to 1 
mm of the real object. The artificial lighting system for the 
shots is comprised of halogen lights with temperatures 
sufficient to taking indoor shots. 
  
Figure 7 
The choice of aerial triangulation as a calculation instrument in 
orienting the block has enabled reduction to the minimum of the 
entity of the topographic operations to the ground, reducing 
them to the measure of points necessary for the successful 
outcome of the calculation. 
The diagram for positioning the points was ideated in order to 
choose the planar-altimetric control points along the perimeter 
of the block and the altimetric points along the chains 
perpendicular to the direction of the strips. The measurements 
have been taken using a TCA 2003 by Leica. 
Digital photogrammetric software technologies were used. The 
digital photogrammetric systems can now take advantage of the 
  
increasingly advanced technology hardware and development of 
increasingly specific and effective software algorithms. 
For this particular job, we used the digital photogrammetric 
system, Orthoengine PCI, installed on a nominal elaborator 
equipped with stereoscopic vision, double monitor and a 
trackball, plus a mouse, for controlling the collimating mark. 
The stereoscopic vision system uses alternated liquid crystal 
polarisation and passive goggles and is located in front of the 
main monitor. 
Management of the images is based on a pyramid system of 
memorisation (Image Minification) in which the original image 
is used to create other resampled images with a lower geometric 
resolution, in order to more quickly handle the zoom and 
handling functions. 
The following phases are used in the system: 
e acquisition of the images 
e interior orientation 
e aerial triangulation 
e generation of the DTM 
e realization of the orthophoto 
Files relating to images of the photogrammetric shots taken and 
saved in the TIFF format have been imported into the 
rectification system with insertion of parameters relative to the 
calibration certificate of the camera; in the event the images are 
devoid of distortion, the values relative to the distortion of the 
lens are set at zero. At the end of this phase, the system 
automatically creates the image pyramid for every shot. 
Interior orientation consists of collimating the corners of the 
images; the procedure is partially automated, and after 
collimating the first two corners, the software prompts the 
position of the other corners. 
In the triangulation phase, the control points acquired are 
collimated thanks to the topographical survey campaign and tie 
points are distributed (Figure 8) according to the appropriate 
structure of the overlapping areas of the models. 
fle Project Preparation Extraclion Products Ouipot Preferences Took — 
Figure 8 
Final compensation is preceded by a procedure called "Blunder 
Detect" where the individual phases involved in the calculation 
(connection of the models, the strips, distribution of the support 
points) are tested. 
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