The research took the whole summer, and I spent most of my fall semester daydreaming about the project instead of paying attention in class. I targetted early March because that's when UIUC holds the annual Engineering Open House, where I presented my work to hundreds of kids, college students, and research professors. All the work is done by the vision algorithms that read the webcam input. Research-wise, the most important element is that I only use one camera and can get 3D information from the 2D image. Most researchers use a stereo-pair of cameras, where the camera disparity allows 3D reconstruction just as our two eyes do.
Color is used to determine the lightsabre's position.
I train the program on color images of the lightsabre, which is a bright neon-green. After that, I can easily determine the ends of the lightsabre. Now we have the 2D positions of both ends of the lightsabre. If I stopped there, that would be just as far as the RealityFusion guys go. As far as I can tell, they only use 2D images for 2D control.