Information Technology Reference
In-Depth Information
3.2
Marker Detection Module
The marker detection module has the infrared floodlight at the center, and the infrared
cameras are placed symmetrically. By using infrared light, it is possible to reliably
detect the markers unaffected by light from the projector in the darkroom.
The infrared floodlight and infrared camera are positioned facing vertically upward
ceiling means because it is believed that in this way occlusion will not occur when the
user peers into the center of the system from above the device. And the use of two
cameras is in order to widen the field of recognition.
3.3
AR Markers
With the 1.8m square size of the performance stage and the efficiency of the projec-
tors used on this occasion, 1.3m above the floor was the highest point in the projec-
tors' projection range. Therefore, as a marker that the camera could recognize up to
this point, an 80mm-square AR marker was placed in the center of a 95mm-square
acrylic plate.
To estimate the marker's position and orientation, an ARToolKit was used, which
could estimate position and orientation at 30fps.
3.4
Fireworks Device
The fireworks device (figure 4) plays audio in time with the fog dispersal and image.
The fireworks device is fitted with an ultrasonic oscillator, water storage tank, ventila-
tion fan, mbed (microcontroller), speaker, vibration speaker, wireless module, battery,
microSD, MP3 decoder IC, and AR marker, and can be controlled wirelessly.
These components are controlled by the internal microcontroller with the signal
sent from a computer. The fog is generated using the ultrasonic oscillator, and about
90ml of water is spouted as fog per hour. Furthermore, the form of fog screen from
user's view is approximately inverted triangle of which height is 0.15m and base is
0.15m. About 10 users can see the contents on the fog simultaneously. The water tank
can hold about 40ml of water so fog can be generated for a maximum of about 20
minutes. Fitting vibration speakers, which emit sounds when it vibrate and are at-
tached to the device, mean that the user experiences vibration simultaneously with
audio playback. Ventilation from the fan ensures that the fog doesn't disperse and the
projected image is vivid.
3.5
Contents
For the purposes of the test, the experience lasts for three minutes. During that time,
six visual contents are shown and switched every 30 seconds. Each time, the visual
contents are displayed in the order: flames, cherry blossom petals, sunflower, fire-
works, Japanese maple leaf, and snowflake. This sequence was first carried out like a
regular fireworks display, and subsequently became a conscious representation of the
four seasons.
