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The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B5. Beijing 2008 
The digital camera resolution (1024x768) provides a good allows to overlap the point clouds to the images and to snap to 
quality of the images collected and a suitable photogrammetric the points surveyed with the laser-scanner, as shown in Figure 5. 
use of the images. 
2.3 Survey products 
The products obtained with the Road-Scanner are the following: 
1. 3D-routes and topologically connected road graphs, 
according to the GDF specifications and compatible with the 
most common Geographical Information Systems. 
2. Facility management database, containing all the road 
components: road size, signs, posters, lamps, pavements, 
sidewalks, guard-rails, tunnels, retaining walls, etc. 
3. Geo-referenced images acquired with the video system in 
JPEG or AVI format, used in the post-processing phase, are 
also delivered to the end user for virtual inspection of the 
road network. Virtual inspections through the consultations 
of movie are highly regarded by the public administration 
because they allow a quick and easy check of the status of 
the road network. 
4. Road pavement roughness (IRI - International Roughness 
Index), surveyed with the Dynatest profiler certified ASTM 
E950 Class 1. 
5. Road cross sections surveyed with the FARO helicoidal 
laser-scanner. The resulting sections have an angular range 
of 320°, and a distance range of 80 m, at a 10-20 step 
(variable by vehicle speed). The clouds of scan-points are 
geo-referenced. 
The different data can be processed using the photogrammetric 
application Road-SIT Survey, developed by Siteco Informática 
S.r.l., and with the FARO special applications or with the most 
widespread CAD and GIS products. 
The software suite allows the operator to determine the 
coordinates of all requested items, as shown in paragraph 1.2. 
Moreover all the data collected can be exported in standard 
DXF/DWG files and imported in the most common CAD 
software for the production of tables and drawings (Figure 4). 
Figure 4 - A CAD drawing generated with the Road-Scanner 
system 
All the GPS/IMU data, vehicle positions and orientations, are 
stored in a Microsoft Access database, The geo-referenced 
images are stored in motion pictures in AVI format, accessible 
from the photogrammetric application. The user interface 
Figure 5. Snapping to point clouds overlapped to images 
So it’s possible to determine the coordinates of the items both 
by using photogrammetric approach and by the laser points, by 
a specific “snap” tool. 
2.4 Survey operations 
The survey was performed during October 2007 in both 
directions. Part of the area is located in the historical City 
centre of Bologna that maintains the medieval structure and 
presents urban canyons. Some areas are characterized by very 
poor sky visibility, not good for GPS precise positioning. 
For this reasons a pre-survey campaign was performed some 
days before in order to find the best places to receive GPS 
signal along the project track. This expedient has permitted to 
plan many stops in these areas, during the survey, with the aim 
to reduce widely the INS drift in case of GPS outages. 
In order to avoid traffic problems and obstacle such as parked 
cars or moving vehicles the complete track was a priori divided 
into some stretches and the roads were closed to private and 
public traffic. 
All the underground track develops in urban area so, in order to 
have a more suitable description of the territory, the step 
between images has been set to one meter (e.g. for road 
inventory a three meters step was used). 
In order to obtain the best results and a most detailed laser 
survey the vehicle speed was never greater than 20 km/h. This 
permits to acquire a scan line every 15-18 cm, as the Laser 
Scanner mirror rotation speed is set to 30 Hz. Every scan line is 
composed by 4000 scan points. This allows to survey with high 
accuracy the street area and all the requested data. 
In order to check the accuracy of the coordinates obtained 
through photogrammetry and laser scanner, a survey campaign 
in RTK mode was performed after the MMS campaign. In 
figure 6 two pictures represent some points identified in the 
images by MMS and measured using RTK. The location of