- Name of the technology: FreeTrack
- Link: http://www.free-track.net/english/
- Price: Free
- Popularity: NA
- Minimal physical requirements: The patient has to be able to move his eyes freely.
FreeTrack is a free optical motion tracking application for Microsoft Windows, released under the GNU General Public License. Its main function is inexpensive head tracking in computer games and simulations but can also be used for general computer accessibility, in particular hands-free computing. Tracking is sensitive enough that only small head movements are required so that the user's eyes never leave the screen.
Head motions are tracked with six degrees of freedom (6DOF), specifically; yaw, pitch, roll, left/right, up/down and forward/back. This is done by means of a video capture device, typically a webcam, which is placed in front of the user and tracks a rigid point model headpiece. This point model usually consists of infrared LEDs but can also be normal LEDs and even retroreflective material illuminated by a source of infrared light.
FreeTrack can output head tracking data directly using TrackIR™, SimConnect and FSUIPC interfaces, programs that support these interfaces are regarded as having FreeTrack support. General input devices can also be emulated, specifically mouse, keyboard, and joystick (via PPJoy).
To operate properly, Freetrack needs markers in order to represent the position of your head in space.
Depending on the selected mode ,Freetrack will need 1 (Single Point mode), 3 (3 Points Clip mode, 3 Points Cap) or 4 (4 Points Cap mode) markers.
These markers, located on a support (usually a cap for Single Point and 4 Points Cap modes, or a clip fastened on your headset for 3 Points Clip mode) are in fact Light Emitting Diodes (LEDs). Detected by your webcam, they allow the Freetrack software to convert your head movements in data flow which can be used by your game/simulator.
In order to use Freetrack day or night, choice of IR (Infrared) LEDs is advised. Thus, your webcam (equiped with an infrared filter) will only detect the markers and will not be affected by other light sources.
The vast majority of webcams are appropriate for Freetrack use.
The main advantage of this system, is his low cost (less than about ten euros), assuming you already own a webcam. In the other case, you'll have to count a webcam's price in the Grand total.
As an infra-red filter, a good tip is to use two or three dark photograph negatives (or better, not exposed) superimposed and installed in front of the cam lens.