Andrew writes –
A while back, Roo Reynolds posted about his experiments with Reactivision. Reactivision is a really neat way of building whatâ€™re called tangible user interfaces; itâ€™s a bit of software which reads in video being captured by a webcam and tracks the position (and rotation) of special blobs called â€œfiducial markersâ€. In other words, it can work out where, in the cameraâ€™s field of vision, these objects are, and what way theyâ€™re facing.
Iâ€™ve mentioned this thing in passing before, actually, but I didnâ€™t think anything more of it at the time. Rooâ€™s post mentioned that the core vision library was open source, though, and thereâ€™s a Processing library, so one night on my way home from work, I decided to buy a cheap Â£20 webcam from Tesco.