Full text: New perspectives to save cultural heritage

H. Mara and M. Kampel 
Pattern Recognition and Image Processing Group, Institute for Automation, Vienna University of Technology, 
FavoritenstraBe 9/1832, A-1040 Vienna, Austria, Fax: +43(1)58801-18392 
e-mail: {mara, kampel}@prip.tuwien.ac.at 
KEY WORDS: Cultural Heritage, Automation, Development, Processing, Reconstruction, Profile-Line, Pottery. 
Motivated by the requirements of the present archaeology, we have been developing an automated archivation system 
for archaeological classification and reconstruction of ceramics. Our system works with the profile of an archaeological 
fragment, which is the cross-section of the fragment in the direction of the rotational axis of symmetry. Ceramic fragments 
are recorded automatically by a 3D-measurement system based on structured light. The input data for the estimation of 
the profile is a set of points produced by the acquisition system. The profile is used to reconstruct the original pot. 
Our approach consists of several steps, starting by calculating the proper orientation, which describes the exact positioning 
of the fragment on the original vessel. Next the profile line is computed and several measurements, like the diameter and 
height of the vessel. After evaluating the profile line a virtual pot is reconstructed. 
The performance of the proposed algorithm was tested on real data and the results are presented in this paper. 
Today’s archaeology requires the storage, reconstruction 
and classification of ceramics, which is done manually. So 
we were motivated to develop an automated system, which 
meets the requirements for automation. A large number of 
ceramic fragments, called sherds, are found at every ex 
cavation site (Figure 1). The physical characteristics of 
archaeological pottery are used in archaeometry (Leute, 
1987) to assess cultural groups, population movements, 
inter-regional contacts, production contexts, and technical 
or functional constraints. Therefore an analytical tool with 
a defined methodology is required for classification of ar 
tifacts (Orton et al., 1993). 
Fragments are documented by being photographed, mea- 
Figure 1: Boxes filled with ceramics stored in archives. 
sured, and drawn; then they are classified. The purpose of 
classification is to get a systematic view on the excavation 
perform archaeological research. The correct profile and 
the correct axis of rotation are thus essential to reconstruct 
and classify archaeological ceramics. 
Archaeologists use characteristic points of the profile line 
and their distance ratios to determine which type of ves 
sel a sherd belongs to (Orton et al., 1993). Figure 2 shows 
the characteristic points of a manual drawn profile line of 
a complete object. The characteristic points shown are the 
inflection points (IP), local maxima (MA), local minima 
(MI), the outermost point, where the profile line touches 
the orifice plane (OP), the outermost point, where the pro 
file line touches the base plane (BP) and the point, where 
the profile line touches the axis of rotation. A detailed set 
of rules for the classification based on the characteristic 
points was discussed in (Mara et al., 2002). 
Figure 2: Manual drawing of a pot, with manually esti 
mated characteristic points 
Traditional archaeological classification is based on the so- 
called profile of the object, which is the cross-section of 
the fragment in the direction of the rotational axis of sym 
metry. This profile line has to be the longest elongation 
The next Section describes the processing of the data start 
ing with the acquisition of the 3D-data. Then the pro 
file line and its estimation using the rotational axis is de 
scribed. In Section 3 experiments and results based on real 
around a sherd parallel to its rotational axis. A two-dimensionaldata-sets, are shown. Finally an outlook tor future work is 
plot of the profile line holds all the information needed to presented.

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