International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004 
  
  
  
  
Figure 1. DesenRec 1.0 photogrammetric software shortcut 
Herein, the monument used as target is a small cylindrical 
tower placed next to the old Turia riverbed (Figure 2). This 
tower has an approximate radius of two meters and it is about 
six meters in height. 
  
  
Figure 2. Pictures of the small tower (front and back) 
The main request was to plot the whole exterior shape of the 
tower up to a detailed map scale (1:50). 
3.1 Preliminaries 
Previous to the tower development, it was mandatory to take 
some pictures on the job, as well as measuring some ground 
control points. A total of eight digital images were taken 
around the tower with a CANON EOS D60 digital camera; a 
15 mm principal distance was selected for this purpose, 
Maximum image resolution was chosen: 3.072 x 2.048 
pixels. 
After, some basic surveying tasks were carried out in order to 
determine some object points, both on the ground and on the 
small tower. All the ground control information was least- 
squares adjusted. Finally, only the points fitting the outer 
cylindrical shape were used to compute the best circular 
section of the cylinder (simplified tower). Output parameters 
were the centre of the cylinder as well as the radius. The 
whole set of parameters was determined by DesenRec, and 
there was no need to input any approximate parameters. 
Figure 3 shows the control points distribution used for the 
adjustment. 
  
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Figure 3. Top view of the outer part of the cylinder after 
defining the best circle passing through control 
points. 
The mean square error of unit weight after the adjustment 
was only 1.2 cm. Once the cylindrical shape was established 
in 3D, a distortion model was computed. Thus, it was 
possible to analyse the monumental structural deformation 
(Figure 4). Contour line number 0 in Figure 4 means that 
there is no discrepancy between the ‘real’ surface and the 
analytical one. 
From the previous data, it was inferred that the lineal 
development of the small tower should be 12.428 m. The 
height of the tower was 6.023 m. Therefore, the best fitted 
and developed tower surface could be easily computed. 
3.2 Processing 
The processing stage takes into account the photogrammetric 
and digital processing purposes. The first one, dealing with 
the determination of the interior and exterior orientation 
parameters to spatially relate the image to the object 
(Tortosa, 2003). The second one, filtering and correcting the 
radiometric image values, and, last but not least, allowing the 
image extraction of right patches from the developed images. 
    
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