NA SENDA DA IMAGEM A Representação ea Tecnologia na Arte

Fig. 15. Viewpoint 2 gesture 2-5-4-5-2
VI. NAVIGATION
We didn’t want to use key pressing to navigate – it
would not be natural we noticed that when a user wants to
go forward he moves the mouse forward, towards the top
of the screen. The same kind of logic applied to the right,
left and backward movement. We thought that the user
should move in the virtual city with the same kind of
movement with the light.
Fig. 16. The navigation strips are illustrated in the diagram
When the user raises his/her hand intending to go
forward, the pointer should be near the top of the screen,
so I detected that position. A narrow strip (50 pixels high)
near the top, and applying the same principle to the left,
right and bottom.
The user just has to move the light in the direction he
wants to go, without leaving the web cam field of view.
VII. CONCLUSIONS AND FUTURE
DIRECTIONS
O. Tracker and Performance
The ideal solution would be to have just one window
on which no live video image is captured. Something like
where only the light was being captured on a black
background for instance. This would speed up the process
very much, because in reality we don’t need to see myself,
we only need to see the location of the light, the quadrants,
and the sensitive areas for the navigation.
The next step would be the development of special
hardware for light tracking and colour recognition, the
same way other peripherals work (mouse, trackball,
joystick), just feeding light position into the system. This
way the computer just handles the interaction.
P. Tracker feedback
The second real problem was to find a way to translate
the light position to the city program. One of the
alternatives was to copy/paste the modified DirectX
program into the Open GL Performer program. All those
libraries in conflict with each other made it a
pandemonium. So we started surfing the Microsoft
website trying to find some way to communicate between
programs. We kept on looking until we finally found
something very interesting: there was a way to simulate
mouse input, just by calling a function with x,y positions
and a button status. It is somewhat heavy on performance
but it works very well and I can test the city with the
mouse, and turn the tracker on when needed. It takes over
the mouse making the city think the mouse is moving. The
best solution would be a light mouse, specifically
programmed for a webcam.
Q. Functionality
For future developments, we want to do the gestures
only with fingers, so that the interaction gets more natural.
With this solution using a torch the task is not so intuitive
and the undertaking can get arduous after a while of
gesturing because of the webcam’s narrow field of view.
The other big constraint is the size of the monitor, as
we have to concentrate very hard so that my light doesn’t
get out of the field of view of the web cam. It would be
great to have a big screen so that the capturing window
could be larger as well.
We think the way to extend this system to a more
natural interface is to use a big projection screen, far away
from the user (a few meters), so the narrow field of view
of the webcam is no longer a problem. Also the user can
now make wide gestures, without worrying about if he/she
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