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3D-RECONSTRUCTION & RE-PRODUCTION IN ARCHAEOLOGY 
M. Ioannides a , A. Wehr 2 3 
a Higher Technical Institute, P.O. Box 20423, CY-1521 Nicosia, Cyprus - gammat@cytanet.com.cy 
b Institute of Navigation, University of Stuttgart, Breitscheidstr.2, D-70174 Stuttgart, Germany - 
wehr@nav.uni-stuttgart.de 
KEY WORDS: Imaging 3D-laser Scanning, CW-laser, Scanning Geometry, 3D-digitization, 3D-Reconstruction, point clouds 
processing, CAD-modeling, Reverse Engineering, Cultural Heritage Recording 
ABSTRACT: 
First an imaging 3D-Laser Scanner (3D-LS) will be presented and its functioning will be explained. The scanning mechanism of the 
3D-LS is realized by two Galvanometer Scanners. Using such a scanning device it is possible to program various scanning patterns 
depending on the application. Therefore, the scanner can be applied for the digitization of small sculptures as well as for digitizing 
interiors of rooms. It has been shown that the 3D-LS is an excellent tool for 3D-Reconstruction. However, using laser scanners for 
digitizing comprehensively archaeological items means that several hundreds of Megabytes must be efficiently processed. This 
problem will be addressed in the second part. It will be shown, how laser scanner data must be processed to obtain NC-programs for 
re-production in archaeology. Here the Advanced Surface Modeling Software Package (ASMOS) developed by the University of 
Stuttgart and the Higher Technical Institute is applied. Also the problem reconstructing solids by using 3D-LS data from different 
overlapping views will be addressed and examples will be presented. Various examples will demonstrate that 3D-LS can be well 
applied in 3D-reconstruction and re-production if sophisticated and powerful software packages are available for processing the 3D- 
LS image data efficiently. 
1. INTRODUCTION 
In the last years 3D-Laser Scanners (3D-LS) have been used 
more and more in 3D-reconstruction and reproduction, because 
very precise 3D-data can be measured in very short time 
intervals. Due to the high point density not only 3D-surface 
models can be generated but also real 3D surface images can be 
derived if intensity data are available. 
In the beginning of 3D surface digitization either with 
photogrammetric means or tactile machines a modeling of the 
surveyed surface was required, because the number of 
measurement points was very limited. Today the problem is 
vice versa. The user obtains a huge amount of data which very 
often contains redundant information. 3D point clouds 
containing more than a million measurement points are typical 
for laser scanner data sets. In order to reduce superfluous data 
again surface models must be generated. This means 
sophisticated processing software is necessary to obtain valid 
data for CAD modeling or even rapid prototyping. As soon as 
CAD data are available 3D-reconstruction can be carried out by 
commercially available CAD software. In this processing level 
reconstruction of volumes are also possible. Therefore, in this 
paper main emphasis will be laid on the modeling 
postprocessing algorithms and software respectively. However, 
before all sorts of algorithms and procedures are discussed and 
analyzed, a 3D-LS developed by the Institute of Navigation will 
be explained. The scanning pattern can be customized by 
software modifications. Therefore, the 3D-LS covers a large 
field of applications as e.g. scanning of sculptures, small objects 
and interiors of rooms. 
2. 3D-LASER SCANNER 
Over the past years the Institute of Navigation of the University 
of Stuttgart has developed several imaging 3D laser scanners 
using continuous wave (cw) semiconductor lasers as 
transmitters and carrying out the slant range measurement by 
applying the phase difference measurement principle which is 
also known as side-tone ranging. Here the intensity of the light 
Figure 1. Principle 3D-LS Setup 
of the cw-semiconductor laser is modulated by the drive current 
with high frequency signals. As the phase difference between 
the transmitted and from the object surface backscattered laser 
light is proportional to the two-way slant range depth 
information can be directly measured. Using high modulation