I'd call it a stretch to say these guys invented it. There is quite a bit of literature on this technique, e.g. http://research.nokia.com/files/hile_landmark_m

I'd call it a stretch to say these guys invented it. There is quite a bit of literature on this technique, e.g. http://research.nokia.com/files/hile_landmark_mum08.pdf http://research.nokia.com/files/hile_landmark_mum08.pdf