CLOSE RANGE ORTHOIMAGE USING A LOW COST DIGITAL CAMCORDER
E. Tsiligiris 3 , M. Papakosta 3 , C. Ioannidis b , A. Georgopoulos c
3 Surveying Engineer, Post-graduate Student, National Technical University of Athens - tsili@hol.gr
b Ass. Prof., Lab. of Photogrammetry, National Technical University of Athens - cioannid@survey.nyua.gr
c Prof., Lab. of Photogrammetry, National Technical University of Athens, Greece - drag@central.ntua.gr
KEYWORDS: Digital Camcorder, Close Range, Orthoimage, Heritage Recording
ABSTRACT:
Video recording and digital photogrammetry are usual techniques to achieve monument morphological and metric documentation
respectively. An all at once approach provides significant cost and time saving, especially when dealing with complicated objects,
which demand multiple photography for their full coverage. Based on this consideration, this paper examines the possibilities of
using a low cost digital camcorder to supply imagery in order to create large-scale orthoimages of a site with adequate geometric
accuracy and radiometric quality, through the usual photogrammetric procedures. The first step of this research is the calibration of
the camcorder at an appropriate test field applying a bundle adjustment. Then, an application took place on one side of the Gate of
Adrianos monument. Still images were captured through a DV card. The manual generation of a DSM and the creation of
orthoimages derived from different initial still images took place in a SSK. Z/I Imaging digital photogrammetric workstation. A
comparison of the achieved accuracy, completeness and cost of this method’s products with the conventional orthophotos of the
monument, which were derived from photos taken with photogrammetric cameras, was made. Finally, limitations of the specific
camcorder’s use, for the geometric documentation of the monuments, are also described.
1. INTRODUCTION
During the last years digital photogrammetry became a very
useful tool not only for site recording but especially for
architectural geometric documentation. Many applications exist
in the relevant literature, in which metric or semi-metric
analogue cameras and non-metric digital cameras are used.
Video is an other alternative tool for the documentation of
monuments, in various levels, starting from simple digital
image recording up to the 3D extraction of metric information.
Videometry has developed significantly since 1990 mainly in
the field of industrial applications or for the monitoring of
dynamic phenomena (Tournas, 2003), and in the field of
architectural applications as well. The video capabilities for the
recording and visualizing both real and computer generated
scenes or the readily available output of every CAD,
photogrammetric or visualization tool or even the production of
geo-referenced 3D video (Sechidis et al, 2001), show that it is a
powerful and promising tool for archaeological applications.
Moreover, the development of the Mini-DV and Micro MV-
Network technology is more than rapid making the digital
camcorder to be a low cost solution.
According to the above it was decided that a test should be
performed. The main aim was to investigate the capability of
digital amateur videos for providing usual photogrammetric
products, such as an orthoimage. The application of this work
was carried out on the east side of the Gate of Adrianos
monument, considering as main theme of the camcorder’s
orthoimage, part of a column capital. This monument was built
in the 2 nd century by the Roman emperor Adrianos at the
entrance of the ancient city of Athens. This impressive
construction measures approximately 14 m in breadth and 17 m
in height. It consists of two parts. A lower one which presents a
majestic arch - the main city gate- and an upper part, which is
lighter, ornamented with pillars. Today it is located at
Figure 1. Grayscale Orthoimage of the east side of Gate of
Adrianos and an ortho-detail of the specific column
capital
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