I think the normal way to do something like that is known as "image correlation matching". Googling that phrase should provide some reference material.
On Thu, May 21, 2009 at 1:22 PM, Philip Rosedale <phi...@lindenlab.com>wrote: > Have you seen this video... http://www.youtube.com/watch?v=r7Gn2TyEyHw > > It is a cheap logitech camera tracking a head and head rotation really well > (which you can see by the registration quality of the video overlay). > > This is what we want - simple head position and movement tracking from a > camera. I suppose we could just use the logitech API but that would > restrict us to their cameras. I believe that the code they ship with their > cameras is based on OpenCV? Hence the question. > > Philip > > > Jan Ciger wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Philip Rosedale wrote: > > > Has anyone here worked with camera-based gesture recognition before? > How about OpenCV? Is OpenCV the best package for extracting basic head > position/gesture information from a camera image stream? Merov and I > are pondering a Snowglobe project to detect head motion from simple > cameras and connect it to the SL Viewer. > > > I have done something like that. First of all, OpenCV is does not do any > gesture recognition. It is an image processing library and you need to > know quite a bit about computer vision to be able to use it > meaningfully. I have found this book indispensable for > that:http://oreilly.com/catalog/9780596516130/ , plus a good basic computer > vision textbook. > > If you want to track the orientation of the head with a webcam, that is > doable - NaturalPoint is selling infrared webcams that track either a > single point or a simple rig on your head and translate that to mouse > motion. That is easy enough to do. If that is all you want to do > (translate head motion to 2DOF mouse-like signal), OpenCV is even an > overkill - capture image, threshold it to extract the marker and measure > where it is compared to the initial position. Then use that difference > to steer camera. > > The main issue you will have will be a cross-platform video capture > library. I have yet to find one that is not too buggy and actually works > without doing crazy stuff. OpenCV has some code for capturing video, but > that is mainly for debugging and shouldn't be used for production (it is > *really* buggy and slow). > > On the other hand, if you want to do something more complex - e.g. full > 6DOF tracking, OpenCV is a good starting point. For example, I have the > Minoru 3D webcam (http://www.minoru3d.com/) connected to a 3D tracker on > Linux that allows me to track both the position and orientation in space > - - like a 3D mouse. The tracker is made using OpenCV. However, > calibrating that is not something for an average Joe to do ... > > Regards, > > Jan > > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.9 (GNU/Linux) > Comment: Using GnuPG with Mandriva - http://enigmail.mozdev.org > > iD8DBQFKFbPZn11XseNj94gRAmdkAJ9fbD8bpCVqK3KtJ1FTunFVSmVMTgCfRuvB > VABbYQzKrgfLkcCI8i8iclk= > =kMun > -----END PGP SIGNATURE----- > > > > _______________________________________________ > Policies and (un)subscribe information available here: > http://wiki.secondlife.com/wiki/SLDev > Please read the policies before posting to keep unmoderated posting > privileges >
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