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LASER SCANNING AND PHOTOGRAMMETRY FOR THE DOCUMENTATION OF A 
LARGE STATUE - EXPERIENCES IN THE COMBINED USE 
Ch. Ioannidis, Maria Tsakiri 
School of Rural and Surveying Engineering, National Technical University of Athens, Greece 
(email: cioannid@survey.ntua.gr, mtsakiri@central.ntua.gr) 
KEYWORDS: Cultural Heritage, Laser Scanning, Modelling, Archaeology, Close range photogrammetry, Monuments in seismic 
areas, Data capture, Statue 
ABSTRACT: 
Cultural heritage applications involve measurements at different possible scales. While photogrammetry and metric surveying 
techniques can be suitable for archaeological sites and buildings, they present certain disadvantages for smaller and more complex 
objects such as statues. Laser scanning technology with its automated data capture capabilities is bringing new perspectives and can 
satisfy most requirements of this type of applications. This paper describes a practical example based on the combined use of digital 
photogrammetry and laser scanning techniques with an aim to create a geometrically accurate 3D model of the ancient statue of 
Hermes of Praxiteles, which is housed in the archaeological museum of Olympia in Greece. A comparative evaluation of the two 
techniques in the data capture and modelling of the statue is discussed and typical results of the models are presented. 
1. INTRODUCTION 
Throughout 20 th century, photogrammetry has almost been the 
exclusive technique implemented for the geometric recording 
and documentation of large monuments and complex irregular 
structures, such as statues. Sensitive and fragile objects, 
consisting of a variety of surfaces usually with many curves and 
holes, could be restituted in analog or digital 3D form through 
photographic imaging as a non-contact method. However, the 
restrictions of stereoscopic photography in combination with 
the complexity of the object, poses several limitations for the 
detailed recording of objects, which in an indirect way can also 
affect the obtained accuracy. 
The recent advances in terrestrial 3D laser scanning have 
indicated that this technique has the potential to serve as a 
powerful tool for architectural and archaeological recording. 
The advantages manifest specifically for the recording of 
complex objects, such as sculptures and statues. Examples of 
applications using laser scanning techniques with encouraging 
results are found in Adolfsson (1997), Beraldin et al. (2000), 
Levoy et al. (£000), Rocchini et al. (2001), Henz (2002). 
Terrestrial scanners may be categorized into two groups: 
• Triangulation scanners, which consist of a laser and a CCD 
housed in a single unit. The CCD is used to record the 
displacement of a stripe of laser light projected onto an 
object. Usually the seamier to object distance is less than 2m 
(close-range scanners). This type of scanners has geometrical 
resolution and accuracy better than 1mm. • 
• Time of flight scanners (terrestrial LIDAR), which use a 
pulsed laser to measure the range to a point on an object’s 
surface. There are several manufacturers who currently 
provide scanners of this type, like Cyra Technologies, 
Callidus Precision systems, MENSI, Riegl Laser 
Measurement Systems, Zolleral Froehlich etc, which have 
range distance between 2-100 m and resolution of few mm 
(Kern, 2001). These systems do not provide satisfactory 
accuracies for applications requiring recording of complex 
monuments. In addition, the speed of data acquisition is 
much slower compared to the triangulation scanners. 
The development of varying types of scanners cannot imply 
that the 3D documentation of sizeable and complex objects, 
such as large statues, has become trivial or that scanning can 
replace all other imaging techniques. On the contrary, there are 
several technical difficulties associated with the use of 
scanning, such as data management due to the huge quantities 
of data generated on-site, and requirements for sophisticated 
processing capable of performing registration and merging of 
large numbers of scans. Furthermore, the type and format of the 
products generated by scanning techniques, such as point 
clouds, triangle meshes and 3D models, are different to those 
usually expected or are familiar with by the end users like 
architects, archaeologists or conservators. 
Figure 1. The Hermes statue as is exhibited in the museum