MagicMouse: an Inexpensive 6-Degree-of-Freedom Mouse
HIT Lab NZ
Lincoln University, New Zealand
HIT Lab NZ
An inexpensive computer input device was developed that allows
the user to operate within both 2D and 3D environments by
simply moving and rotating their fist.
Position and rotation
around the X, Y and Z-axes are supported, allowing full six
degree of freedom input.
This is achieved by having the user
wear a glove, to which is attached a square marker.
and rotation of the hand is tracked by a camera attached to the
computer, using the ARToolKit software library.
calibration, normalisation and mapping of the data converts hand
motion into meaningful operations within 2D and 3D
Four input scenarios are described, showing that
the mapping of the position and rotation data to 2D or 3D
operations depends heavily on the desired task.
Input Device, six degrees of freedom, camera, 2D, 3D
With the constant increase in availability and performance of 3D
graphics cards, there comes a parallel need to be able to
intuitively perform operations in 3D environments such as
navigation, and control.
These operations benefit from the ability
to translate along and rotate about the X, Y and Z axes, defined
here as Xpos, Ypos and Zpos, and Xrot, Yrot and Zrot
Previous research has shown that manipulation
operations are most effective with the ability to operate in six
degrees of freedom (DOF) simultaneously (WARE 1990).
Three-dimensional input devices are available in many forms,
but generally they are either limited or very expensive, or both.
The keyboard can be used to navigate in three dimensions, but it
is not designed for this, so it lacks both intuitive and analogue
Joysticks are the cheapest dedicated tools available, and
can be analogue; however, they only offer more than 3 DOF by
adding "hat" buttons (mini joysticks) and sliders, which are not
always very intuitive.
A variety of ultrasound, magnetic,
mechanical and radio frequency devices can be attached to a hand
to track it, but most only determine position, require the user to be
tethered to the machine and are expensive.
This paper offers a cheap, intuitive, 6 DOF alternative using a
black cardboard square, a standard USB video camera and some
computer vision software (ARTOOLKIT 2002).
The MagicMouse has two key software components: ARToolKit
which generates a transformation matrix representing the hand;
and functions that extract Xpos, Ypos, Zpos, Xrot, Yrot and Zrot
from the matrix, normalise them to range from –1 to 1 (using
calibration data) and map them to a variety of operations.
ARToolKit is a free, open-source C software library that uses