- 83 - 
can not be estimated. However, we can measure the bounding 
cuboid and compare it with the dimensions of the model. Table 
1 summarizes the results. The resulting models, shown from 
three views, are depicted in Figure 16. All models are built with 
an octree resolution of 256 3 and using 360 views. 
Vessel #1 
1 
> 
% 
• 
» 
m 
4 
V 
V 
Sherd #1 
Sherd ii2 
Figure 16. 3D models of two vessels, two sherds and a cup 
6. CONCLUSION 
Many In this paper a combination of a Shape from Silhouette 
method with a shape from Structured Light method was 
presented, which create a 3D model of on object from images of 
the object taken from different viewpoints. It showed to be a 
simple and fast algorithm, which is able to reconstruct models 
of arbitrarily shaped objects, as long as they do not have hidden 
concavities, i.e., concavities not visible in any of the input 
images. For concavities visible to the active system, results 
show that the computed volumes provide the correct model. The 
algorithm is simple, because it employs only simple matrix 
operations for all the transformations and it is fast, because even 
for highly detailed objects, a high resolution octree (256 3 
voxels) and a high number of input views (36), the 
computational time hardly exceeded 1 minute on a Pentium II. 
Already for a smaller number of views (12) the constructed 
models were very similar to the ones constructed from 36 views 
and they took less than 25 seconds of computational time. 
For archaeological applications, the object surface has to be 
smoothed in order to be applicable to ceramic documentation, 
for classification, however, the accuracy of the method 
presented is sufficient since the projection of the decoration can 
be calculated and the volume estimation is much more precise 
than the estimated volume performed by archaeologists. 
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8. ACKNOWLEDGEMENTS 
This work was partly supported by the Austrian Science 
Foundation (FWF) under grant PI 3385-INF, the European 
Union under grant 1ST-1999-20273 and the Federal Ministry of 
Education, Science and Culture.