A human version of the classic arcade game Pacman, superimposing the
virtual 3D game world on to city streets and buildings, is being
developed by researchers at Singapore.
Players equipped with a wearable computer, headset and goggles can
physically enter a real world game space by choosing to play the role
of Pacman or one of the Ghosts.
A central computer system keeps track of all their movements with the
aid of GPS receivers and a wireless local area network.
The Human Pacman was developed by Adrian David Cheok and his team at
the Mixed Reality Lab, National University of Singapore.
Merging different technologies such as GPS, Bluetooth, virtual
reality, wi-fi, infrared and sensing mechanisms, the augmented
reality game allows gamers to play in a digitally-enhanced maze-like
version of the real world.
It has been selected as one of the world's top 100 high-impact and
visionary technologies and will showcased at the Wired NextFest 2005
in Chicago, US, which runs from June 24 to 26.
Combining both real and virtual elements, the game allows the human
Pacman to 'see' virtual cookies with the aid of the special headset
scattered on the street which the player can then 'eat' by walking
The game as seen through the eyes of a player
Ghosts get to 'devour' the player by tapping them on the shoulder
when they catch up to them within the game area.
In return, Pacman gets the ability to temporarily neutralise them and
add to his virtual powers when he finds and picks up Bluetooth-
embedded physical sugar jars scattered in the real world environment
by a game coordinator.
The player's locations are also wirelessly updated to a virtual 3D
Pac-world where online gamers can view their progress and participate
by helping either Pacman or the Ghosts through text messaging.
Test runs were conducted on the university campus within a 70m by 70m
game zone. With a four-player minimum, a typical game was played out
in about 10 to 20 minutes.
Other institutions focused on creating similar games include the
University of Southern Australia, which has developed an augmented
reality (AR) version of the Quake game.
Accuracy and positioning are some of the major challenges facing
researchers creating deployable AR versions of complex games.
"Most attempts at AR games, like AR Pacman or AR Quake, rely on
having very accurate models of the physical world such as the trees,
cars, buildings, etc. which is practically impossible," said Blair
MacIntyre, Director of the Augmented Environments Lab at Georgia
The main challenge of course lies in placing the models in the
right place, so that, for example, we won't see a Pacman walking into
the wall of a castle
Adrian David Cheok, Mixed Reality Lab
"First, the world is just too complicated, and second, it changes too
much - cars and people move, trees grow, etc."
The research team at Singapore says though that a totally accurate
real world model is not necessary.
"What we seek is to create an alternate version of representing the
real-world by some fantasy landscape," says Mr Cheok.
"An office blocked could be replaced by a castle. We do not really
need to have an accurate model of the environment, just a rough gauge
"The main challenge of course lies in placing the models in the right
place, so that, for example, we won't see a Pacman walking into the
wall of a castle."
With current positioning technologies, this kind of accuracy is still
a major issue. Typical GPS receivers have an accuracy of about 10 to
30 meters, but for a flawless gaming experience augmented reality
games need the error margin to be within the millimetre range.
Tracking players also becomes impossible when they get too close to
high-rise buildings that block GPS signals.
To combat these issues, the Singapore team selected a wide open space
as the game area and with advanced Long Range Kinematic (LRK) GPS
technology they say they are able to maintain a maximum error level
of 30 cm.
The more conventional way to play Pacman
If a player's position is lost, the system tries to get the player's
orientation through a digital compass, detect the number of steps
taken, and predict their current position.
"This is by no means a foolproof method, as the errors do
accumulate," says Mr Cheok. "However, it does serve as a feasible
temporary solution in case of GPS-signal loss."
However the real drawbacks to creating commercial AR games are the
An entire system costs anywhere from $10,000 to $20,000. It is
expected to take a number of years before the technology can be truly
affordable to the average gamer.
Some of the AR gaming technology developed at the University of South
Australia is being modified for consumer use.
The researchers have created a start up company called A-Rage that
plans to launch augmented reality game engines into market with a
target price tag of AUD$500, by the end of 2006.
Experts believe AR technology will revolutionize the gaming
experience creating an arena where people move about, socialising and
interacting with each other instead of being glued to a computer
"These games symbolize the dawn of an era where real and virtual
interactive experience will form part of the routine of our daily
lives, allowing users to indulge in the seamless links across
different domains be it for entertainment or socialising," says Mr