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EXPLORING A BYZANTINE CRYPT THROUGH A HIGH-RESOLUTION TEXTURE 
MAPPED 3D MODEL: COMBINING RANGE DATA AND PHOTOGRAMMETRY 
J - A Beraldin *, M. Picard , S.F. El-Hakim , G. Godin 3 , C. Latouche 3 , V. Valzano b , A. Bandicra h 
a Institute for Information Technology, National Research Council Canada, Ottawa, Ontario, Canada, K1A OR6 
b SIBA Coordination, University of Lecce, Lecce, Italy, 73100 - siba@siba2.unile.it 
Commission V, Working Group V/2 
KEY WORDS: Cultural Heritage, Virtual Reality, Laser scanning, Three-dimensional, Reconstruction, Texture, Registration, 
Photo-realism. 
ABSTRACT: 
In recent years, high-resolution recording of heritage sites has stimulated a lot of research in fields like photogrammetry, computer 
vision, and computer graphics. Numerous algorithms and methodologies have been proposed in the literature. In practice, what a 3D 
photographer needs is a commercially available solution to this so-called as-built documentation. In this paper, we present an 
effective approach for photo-realistic 3D model building from the combination of photogrammetry and 3D range data. The method 
is applied to the virtualization of a Byzantine Crypt where geometrically correct texture mapping is essential to render the 
environment accurately in order to produce enticing virtual visits, apply virtual restoration techniques on the frescoes and remove 
architectural elements that have been added over the years so that the site can then be viewed in the correct historical context. A 
movie entitled “CARPINIANA” was created in order to demonstrate the results. 
1. INTRODUCTION 
The capacity to create, display, manipulate, archive and share a 
digital representation of the shape and appearance of an 
existing object (as-built documentation) finds a most 
challenging class of applications in high-resolution recording of 
heritage-related objects and sites. Once the object or site has 
been “virtualized”, one can use immersive technologies to 
study or to promote a cultural site using a virtual 3D visit. 
However, beyond photo-realistic rendering, a 3D model 
contains a wealth of information that can be analyzed and 
enhanced. Features that are small or only visible from a 
distance can be interactively examined, thus, allowing the study 
of fine details such as tool marks or surface texture. 
Furthermore, sites that must be closed for conservation reasons 
can still be studied and visited once a 3D model has been 
created. Computer-based visual enhancement and analysis 
techniques can be applied to the digital model in all of these 
situations. One such application is found in virtual restoration 
of an historical site. As opposed to "traditional" restoration that 
is performed on the physical object or site (usually not 
reversible), virtual restoration is applied directly onto the 
digital copy hence reversible. For instance, it allows the 
optimization of the legibility of textual and artistic informative 
data, without turning to interventions often traumatic for the 
original copy (SIBA Web Site). Or in some instances, 
architectural elements that have been added over the years can 
be removed and the digital 3D model of a site can then be 
viewed in the correct historical context. 
As a way to demonstrate the proposed modeling method, we 
selected a Byzantine Crypt (see Fig.l). Though not part of a 
typical tourist itinerary in Italy, this rupestrian site contains 
amongst the oldest Byzantine frescoes that signed and dated. It 
is known as the Crypt of Santa Cristina and is located in 
Carpignano Salentino in Apulia (Bandiera 1980). This Crypt 
measures about 16.5 m by 10 m by 2.5 m. This one thousand 
year old crypt presented many challenges from the technical 
and historical point of view. The Crypt also contains an altar 
and three pillars added during the Baroque period. In order to 
model a complete site like this Crypt, a 3D photographer would 
have to be skilled in a number of 3D modeling procedures. The 
3D photographer could be a specialist that does this type of 
work on contract basis. Or, in cases where the property of data 
is of concern, it can even be a technician directly link to the 
agency requesting the work. Whichever case it may be, the 
combination of range data with photogrammetry was examined 
from a user point of view. Numerous papers have dealt with 
this issue, but one problem remains to be addressed i.e. the 
availability of commercial tools for both 3D modeling and 
high-resolution texture mapping onto dense 3D models. Very 
few solutions exist on the market addressing this issue. We 
report an effective approach based on commercial software to 
the problem of high-resolution photo-realistic texture mapping 
onto a 3D model generated from range images. Section 2 
presents an overview of the processing pipeline and section 3 
describes the elements used in that pipeline. Section 4 shows 
how these elements were put together for the Byzantine Crypt. 
Finally, concluding remarks appear in section 5. 
a) b) 
Figure 1. Byzantine Crypt IX-X, a) the two outside entrances, b) 
view of the interior located underground. 
* Corresponding author. J-A Beraldin, angelo.beraldin@nrc.ca, http://www.vit.iit.nrc.ca NRC 44916 
Currently completing its Master’s thesis (Université Laval, Qué, Canada) as a guest worker at the NRC Ottawa