CI PA 2003 XIX 11 ' International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
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Figurel : Definition of the coordinate system of a RIEGL LMS-Z360 
Laser Scanner (above). Scanner equipped with digital camera 
mounted on top (below). 
Project Coordinate System (PRCS) is the major 
coordinate system used within RiSCAN PRO. For 
example, PRCS can be an already existing coordinate 
system at the scan site, e.g., a facility coordinate 
system. RiSCAN PRO requires that all geometry data 
within this project coordinate system can be 
represented by single precision numbers (7 significant 
digits). For example, is mm accuracy is required, the 
maximum coordinates should be less than 10 km. 
Global Coordinate System (GLCS) is the coordinate 
system into which the project coordinate system is 
embedded. Usually, coordinates in the global system 
may contain very large numbers. 
Camera Coordinate System (CMCS) is the 
coordinate system of the camera mounted on top of the 
scanner system providing high-resolution images. 
Figure 2 shows an example for the coordinate systems 
GLCS, PRCS, and SOCS. The object is a building seen 
from a bird’s view. A project coordinate system is 
defined with the y pr - axis being parallel to the long 
side of the building and the origin of the PRCS 
coinciding with one corner of the building. PRCS has 
to be a right-handed system. GLCS in the example is a 
left-handed system, e.g., northing, easting and 
elevation. A number of scan positions are indicated by 
spi, where the scanner has been set up for data 
acquisition (see the detailed description on scan 
positions below). Each scan position has it’s own local 
coordinate system (SOCS) sketched by the axes * p i, 
Yspl> Zspl • 
In almost all applications data acquisition is based on 
taking scans from different locations in order to get a 
more or less complete data set of the object’s surface 
without gaps or “scan shadows”. The different scan 
locations are addressed as Scan Positions. When 
starting a new project, i.e., starting a new data 
acquisition campaign, the user initialises a new scan 
position before acquiring data from the scanner. This 
scan position will hold all data acquired at that specific 
setting up of the scanner. 
A scan position is characterized by it’s own local 
coordinate system (SOCS), i.e., the position and the 
orientation of the scanner within the project coordinate 
system. Position and orientation can generally be 
described by 6 parameters (3 for position, 3 for 
rotation) or by a transformation matrix. RiSCAN PRO 
makes use of a 4 x 4 matrix (Msop) addressed as SOP 
information (SOP for sensor’s orientation and 
position). The matrix consists of 9 parameters 
reflecting the rotation (r u to r 33 ) and 3 parameters for 
the translation (ti to |). The use of homogeneous 
coordinates allows computation of rotation and 
translation in a single matrix multiplication. The