Some bright folk, mainly from Stanford University (one from Cornell), have demonstrated a technique to produce photographic images without the use of a camera. The technique exploits Helmholtz reciprocity to allow an image to be recreated from the point of view of the projector that’s lighting the scene, even though there’s no camera at that location. Additionally, it allows the scene to be relit arbitrarily (now that sounds like something I could use!) Quite deep (man) but very interesting. There’s a movie file too, which I haven’t finished downloading yet and a large PDF of the complete paper.
[Update: make sure you see the movie – it’s worth it. BitTorrent download link]