[Flightgear-users] webcam-only headtracker addon (WIP)

[Melchior F. <mf...@ao...>]

Head trackers determine the position and orientation of the computer user's
head, and use this information to modify the view in the artificial 3D world.
Usually, this requires a sensor (e.g. a webcam) and special markers mounted
on a helmet or cap. This can be colored/reflective points or even (IR)LEDs.

There's a (F/OSS) implementation of a head-tracker that only requires a
webcam, without the head gear: EHCI[0] (based on OpenCV[1]). It works with
a face detection algorithm. See the following link for a demo. It shows the
analyzed face features on the left side, and an overlaid 3D head on the
right side.

  http://www.youtube.com/watch?v=BovphSjw_tI

Unfortunately, it doesn't work as well as the film implies. The guy took
care of not turning the head too far and keeping the face rectangle nicely
on screen. If one doesn't do that, then the orientation quickly drifts off,
and one has to reset the tracker.

Anyway, in the hope to see further EHCI improvements in the future, I've
written an fgfs addon that uses the tracker information to control the
pilot's view. It's a separate application that communicates via UDP socket
with fgfs, and there are no changes to fgfs (2.0!) necessary. See the README
for further info:

  $ git clone git://gitorious.org/fg-ehci-headtracker/fg-ehci-headtracker.git

Maybe someone is interested in this *and* can perhaps even send me patches
for improvements/fixes.  :-)

Note that the EHCI library is a bit strange (to put it politely), which
explains some of the fg-tracker weirdness. Also note, that you have to
use it in not too dark environment (or maybe use an IR spot, haven't tried
that yet). And I assume you should have a dual core/cpu machine at least.
The tracker uses quite some cpu power for image processing, so it shouldn't
run on the same cpu/core as fgfs.

m.


PS: don't expect too much!

[0] http://sourceforge.net/projects/opencvlibrary/
[1] http://code.google.com/p/ehci/