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USING OF NON-EXPENSIVE 3D SCANNING INSTRUMENTS
FOR CULTURAL HERITAGE DOCUMENTATION
‘Karel Pavelka, 2 Tomas Dolansky
'Head of Laboratory of Photogrammetry, Tel.:+420224354951, Fax:+420224310774, E-mail: pavelka@fsv.cvut.cz
2 Dept. Mapping and Cartography,Tel.:+420224354605, Fax:+420224310774, E-mail: dolansky@fsv.cvut.cz
Czech Technical University in Prague, Faculty of Civil Engineering,
Dept. Mapping and Cartography, Thäkurova 7, 166 29, Prague 6, Czech Republic
KEY WORDS: 3D documentation, laser scanning
ABSTRACT:
In the framework of co-operation between the Laboratory of Photogrammetry of the Department of Mapping and Cartography, the
Department of Special Geodesy and the Laboratory of Quantitative Methods of Monuments Research (Faculty of Nuclear Physics
and Physical Engineering), new methods of 3D objects documentation are tested on school level. There are two types of 3D scanners
under development: the first type uses triangulation method: the laser is used only as a point or profile marker (rotating platform
system) and the system with 2 cameras and image projector as a structured light source. The second type uses a pure laser technology
“time of flight”. Three small devices for 3D object co-ordinates capturing are being developed at present at the CTU in Prague. The
aim of this research is to develop a small inexpensive device for special purposes of 3D documentation. A combination of several
electronic parts such as CCD camera, laser marker, computer and distance measuring device and laser sensor head (time of flight)
has been used for the instrument development.
1. NEW DEVICES FOR 3D OBJECT MEASURING
In the framework of co-operation between the Laboratory of
Photogrammetry and the Laboratory of Quantitative Methods of
Monuments Research (Faculty of Nuclear Physics and Physical
Engineering), new methods of 3D objects documentation as a
part of the project are tested. Two devices for 3D object co
ordinates capturing are being developed at present. The aim of
the project is to develop a small inexpensive device for special
purposes of 3D documentation. By combining several electronic
parts such as CCD camera, laser marker, computer and distance
measuring device, a new laser sensor has been developed. There
are only few possibilities how to construct laser based 3D
sensors. The principle of these devices is the same: the laser
beam is used as an object point marker (single point or line on
object) and the laser track is recorded by using of a small CCD
camera. The camera and laser position are convergent to the
object, 3D co-ordinates can be computed from laser-camera
basis.
marked object points the real 3D co-ordinates are computed.
The scanning process is demonstrated on Fig.3.
Figure 1. The rotating platform and laser
2. LASER SYSTEM WITH CCD CAMERA AND
ROTATING PLATFORM
For small objects such as small sculptures, vessels or models a
system with rotating platform has been constructed. A laser
beam optically modified to a thin line on the object is recorded
from a basis with CCD camera. A maximum of 25 frames per
second can be used. The measured object is situated on a
rotating platform with a possibility to change the rotating
velocity. All the images are stored on a PC and processed by
using of special software. From the image co-ordinates of
