Fig. 6 a View from Arc de Triomphe, Paris (France). b A tourist looking in our telescope (ver-
4.5 System Initialization
Our aim is that our telescope should be used anywhere in the world. But we had
to develop a procedure to position it ideally. Our system calibration relies on an
estimation of the intrinsic parameters of the pinhole camera model by simplifying
the calibration pattern process. We use classical methods such as proposed in
Gravir-Imag and Sturm ( 1997 ), Tsai ( 1986 ), and Zhang ( 1998 ), and we adjust
them to suit our environment (variable focal length of our camera). For further
details about our calibration procedure one can refer to Chendeb et al. ( 2013 ).
5 Experimenting and Using of the Telescope
An experimentation has been set up on the “ Arc de Triomphe ” ( Paris, France ) dur-
ing the festival “ Futur en Seine ” and presented to tourists (Fig. 6 a).
5.1 Mechanical Architecture
Our telescope is linked to a computer which launches the application. We can
visualize on the screen of the computer what the subjects/tourists get to see
through the Telescope Fig. 6 b. This application consists of displaying information
balloons hovering above the historical buildings in the real landscape.
Those information balloons are more accurate when the subject/tourist zooms
in the landscape with the telescope. For Example, the Fig. 7 a shows pictograms in
information balloons, the Fig. 7 b shows information balloons with the name of the
historical building. Figure 8 shows all the information that appears progressively
according the area of interest of the user.