- Plane 3 
Plane 4 
‘Plane 2 
-— Plane 1 
  
  
ver Fe n ER | e 
n side of the building 
  
    
finding points of known coordinates, through the 
stereorestitution or by measuring on the old plans, which 
were at the same time recognisable on the photos. So, the 
rectification was done by following the method of “known 
directions in space”. In this case, it should be determined: 
- the position of the vanishing points, as intersection of 
bundles of lines having vetrical and horizontal directions 
(parallel in the object) 
- the position of the principal point, by measuring the 
fidutial marks, or in the case they do not exist, as here, 
- nn by knowing the ratio between one horizontal and one 
Fig. 3 Rectified image of plane 2 of the western side vertical distance. These distances are defined on the 
(at scale 1:100) object and measured on the image. 
The whole work was done by using two software 
packages, alternatively: 
a. A S/W package was especially written in AutoLisp, in 
AutoCAD environment where the whole rectification is 
completed (image input in tif format). This S/W 
algorithm executes the calculations needed for: 
- the determination of the vanishing point coordinates, 
by using the equations of vertical and horizontal lines, 
that are parallel in the space and are defined by the 
digitization of their edges on the screen 
- the dermination of the rectification parameters, by 
using two perpenticular distances of known length, or 
in a more general case the ratio between an 
horizontal and a vertical length (the formula is 
broadly known and described in plenty 
A S i Wc photogrammetric papers, i.e. Barnard, 1982/ Novak, 
a € 1992) 
  
Fig. 4 Rectified image of plane 3 of the western side - the determination of the coordinates of the facade 
(at scale 1:100) details, which belong to the particular plane and are 
18 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996