The
Beginnings of Audience Interaction
Below
is an excerpt from the online portfolio of former Carnegie Mellon CS undergraduate
Daniel Maynes-Aminzade. His work pioneered
some of the technologies and techniques used in Audience Interaction-based
projects in the ETC.
The original
porfolio can be found at http://www.monzy.org/audience
The
Cinematrix Interactive Entertainment System
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At
SIGGRAPH in 1991, Loren and Rachel Carpenter unveiled an interactive
entertainment system that allowed members of a large audience
to control an onscreen game using red and green reflective paddles.
In the spirit of this approach, I developed a variety of techniques
that enabled members of an audience to participate, either cooperatively
or competitively, in shared entertainment experiences. These techniques
allow audiences with hundreds of people to control onscreen activity
by (1) leaning left and right in their seats, (2) batting a beach
ball while its shadow is used as a pointing device, and (3) pointing
laser pointers at the screen. All of these techniques can be implemented
with inexpensive, off the shelf hardware. |
Audience movement
tracking allows audience members to control an onscreen game without
the use of physical props. We position a camera at the front of
the auditorium and point it at the audience. We then encourage the
members of the audience to move in certain ways, and analyze the
streaming video to control an onscreen game. For example, audience
members can lean left or right in their chairs to steer a race car
or move a paddle in the video game Pong. Here
are videos of a large audience playing
Pong (7 MB) and
Pole Position (11 MB), a classic car racing game. |
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Another technique
uses pixel differencing to determine the amount of motion in the
crowd. In this "chase" game, the left side of the
audience controls the coyote and the right side controls the roadrunner.
The more that a side of the audience moves, the faster their character
runs. The small image inserts on either side of the screen
show the two sides of the audience, and the bar graphs above them
show the level of audience activity on each side. |
The
common crowd activity of batting a beach ball before a concert
provided the inspiration for another interaction technique. We
project a game on the front screen of a movie theater, and as
the audience bats a beach ball into the air, the ball casts a
shadow on the screen. We point a camera at the screen and use
computer vision techniques to track the ball’s shadow. This tracking
allows the audience to play interactive games using the shadow
of the ball as a cursor.
Here
is a video
of the show (10 MB). |
Missile Command
using beach ball shadow
tracking. The beach ball (top left) casts a
shadow (bottom right) which acts as a cursor.
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It is not uncommon
for members of a large movie theater audience to shine laser pointers
at the movie screen before the film begins. By pointing a camera
at the screen and tracking the dots, we can create compelling interactive
entertainment experiences. The red dots can be attached to a collaborative
paint program or a game that encourages maze navigation or rapid
flocking of laser points to particular locations. At right
is an example of a game in which the audience is encouraged to uncover
a series of hidden images using their laser pointers. This
video
(13 MB) shows the game in action. |
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Whack-A-Hamster
is another game that uses laser pointers as input devices.
The audience directs their laser points at the hamsters to "whack"
them. Here is a sample video
(18 MB). |
I have also used
laser tracking to carry out live audience polls and trivia.
This
is a video showing a poll (9MB), and this
video (10 MB) shows a trivia question. The audience members
use their lasers to point at choices, and the bar graphs continually
update to show the audience's preferences until the time limit is
reached. |
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Shadow tracking
works well with many different objects. The game pictured
at left allows the audience to raise and lower a surface by "holding
it up" with shadows. When this game is shown in a large
auditorium, the audience members in the front row are given pool
noodles (long, cylindrical Styrofoam rods) that they hold in front
of the screen to create shadows. The top of each shadow is
actually the control point on a spline, and the audience attempts
to modify the surface so that the ball bounces into the target.
This
video (11 MB) shows my former research advisor giving it a try. |
Once the shadow
tracking was in place, it was easy to replicate this popular game,
shown at last year's Siggraph. The participants can hold up
the falling cascade of letters using their shadows. Here is
a sample
video (23 MB). |
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