Facade Reconstruction of Destroyed Buildings Using Historical Photographs 
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p* p* p* p* 
-*3 '4 r l r % 
From the model assumption it follows that P is located on the line Q 2 Q 2 between the two vanishing points. Applying the PPT we get 
the image points P\', P 2 ', P 2 ' and P 4 and P 5 \ PP, Pi' and P 8 ', respectively, in a transformed image /'. If we use Q 2 , Q3, and the true 
value for P as parameters of the PPT, the planes E 2 and £ 3 are correctly rectified implying 
p'p’ p'p' 
r \ ‘2 _ r i ‘2 
p;p; Pz p a 
and 
p*p* 
r 5 r b 
P* P* 
*7 Y 8 
P'P ' 
r 5 ' 6 
P'P' 
r l • r 8 
p'p' P'P' 
Thus 1 2 = - 5 6 must hold. 
p'p' p'p' 
Gj r 4 r l ■* 8 
Consider now the function 
/t(x,7, , P 2 , P 3 , P 4 , P 5 , P 6 , P 7 , P 8 ,0 2 , Ö3,/) 
P'P' p'p 1 
r l r l r 5 r 6 
P'P' P'P' 
‘3 r 4 r l r % 
with free parameters x and y as principal point candidates from the range Q 2 Q 2 and points P\ to P$ extracted from the image. The 
function is zero just at the true principal point co-ordinates (X,Y). Determination of (X,Y) is achieved by interval separation starting 
from Q 2 and Q 3 . The value for/we obtain according to formula (2). 
Figures 6 and 7 show two examples of destroyed historical buildings which are desired to be reconstructed. Figures 6 shows the 
Municipal theatre in Athens (Greece) which was analysed for reconstruction (Karras 1999) as well as the Kommandantur in Berlin 
(Germany) in Fig. 7 (Hemmleb 1999, van den Heuvel 2001). 
Fig. 6: Left: historical image of the totally destroyed Municipal theatre in Ath 
ens, right: points forming an equal length ratio on both facade planes 
Fig. 7: View of the Kommandantur in Berlin 
(Germany) from the Meydenbauer archive 
In both images the two visible facades of the buildings were rectified using the presented method. The resulting images are shown in 
Figs. 8 and 9. 
Fig. 8: Rectified facades of the Municipal theatre