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International Archives of the Photogrammetry, Remote Sensing and Spatial [Information Sciences, Vol XXXV, Part B5. Istanbul 2004 
  
3.4 Analysis (Prasat Suor Prat N1 Tower) 
3.4.1 Purpose: The dismantlement and repair construction 
of Prasat Suor Prat N1 Tower in Angkor, Cambodia has been 
enforced by the JSA (Japanese Government Team for 
Safeguarding Angkor) since the middle of September 2002 
(Fig.9). The tower is neighbouring a bank of a pond, and suffers 
the danger of collapse. The method for repair to be employed is 
to take apart all components and to repair the broken 
components and the foundation. Then these components will be 
assembled and reconstructed according to the state of its 
founded period.* * Before the dismantlement, the authors made 
laser scanning of the tower in order to obtain its 3D digital data, 
in August 2002. Then using 3D data of the tower, the 
inclinations of the structure were investigated. 
  
Fig.9 Prasat Suor Prat NI Tower 
3.4. Work process: Prasat Suor Prat N1 Tower is a large- 
scale laterite and sandstone made structure with a height of 18m. 
And there is an air well inside of the structure. In order to get 
the overall 3D data of the tower, it was necessary to build 
scaffolds along the exterior and interior walls of the tower 
(Fig.10,11). ** All measurements (using Cyrax2500) were 
completed in about two weeks and the 3D data of exterior and 
interior walls of the tower were obtained.* * Using 3D data of 
the tower, the inclinations of the structure were investigated. 
First, the intersection of the diagonal lines of the structure's four 
corners of the same layer was identified and assumed to be the 
central point on the layer. Then, the central points of different 
layers were connected by lines, and their inclinations were 
defined as the structure's inclinations (£ig./2). In the same way, 
ups-and-downs of corners on each layer were defined as that of 
the layer. 
   
Fig. 10 Exterior Scaffold Fig. 11 Interior Scaffold 
  
+ 9 M S 9 N 
North Side East Side 
Fig.13 The Inclinations and Ups-and-downs of the Structure 
3.43 Results: As the result of investigation on the 
inclinations of 3D model, it was found that the tower is leaning 
toward northwest direction, which was the same as the finding 
by the verification of manual measurement conducted 
beforehand — (Fig.13). The results of  ups-and-downs 
measurement showed the numerical value mostly interlocked 
with the inclinations. 
It is a valuable result that the same tendency of inclinations and 
ups-and-downs was found between different methods. 
Although it was expected that the numerical value changes with 
methods, it was proved that laser scanning and manual 
measurement can supplement each other in order to increase the 
reliability of accuracy. By making use of advantages of each 
method, combined use of those methods will bring about even 
more valuable and useful results. 
3.5 Exhibition (12 Divine Generals at Shin Yakushi-ji 
Temple) 
3.5.1 Purpose: The 12 Divine Generals at Shin Yakushi-ji 
temple were created more than 1250 years ago (excluding I 
Divine General) arranged on a giant circular podium around 
Main Buddha, Yakushi-Nyorai (Fig.14).** As the 12 Divine 
Generals are made of clay, they have a very weak fault to 
vibration.* * One of 12 Divine Generals unfortunately collapsed 
at time of earthquake in 1854 and the present statue was made 
in 1931. It is unpredictable when sudden crises may occur to 
precious cultural properties. Therefore, these statues were 
recorded as 3D digital models by laser scanner (Fig./5).**In 
order arouse interest in general public with regard to laser 
scanning technology and preservation of cultural properties, the 
authors made CG animation and created DVD content.